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WO2014159456A1 - Régulateur de courant intégré permettant d'entretenir un courant de maintien d'un circuit atténuateur - Google Patents

Régulateur de courant intégré permettant d'entretenir un courant de maintien d'un circuit atténuateur Download PDF

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Publication number
WO2014159456A1
WO2014159456A1 PCT/US2014/023741 US2014023741W WO2014159456A1 WO 2014159456 A1 WO2014159456 A1 WO 2014159456A1 US 2014023741 W US2014023741 W US 2014023741W WO 2014159456 A1 WO2014159456 A1 WO 2014159456A1
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WO
WIPO (PCT)
Prior art keywords
current
power converter
controller
state
phase angle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2014/023741
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English (en)
Inventor
Peter Vaughan
Andrew Bruce Stuart SMITH
Ricardo Luis Janezic PREGITZER
Mingming Mao
Tiziano Pastore
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Power Integrations Inc
Original Assignee
Power Integrations Inc
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Filing date
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Publication of WO2014159456A1 publication Critical patent/WO2014159456A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC
    • H02M5/04—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters
    • H02M5/22—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M5/25—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M5/257—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

  • Embodiments of the present invention relate generally to power supplies. More specifically, examples of the present invention are related to control circuits for use with power supplies that include dimming circuitry.
  • ac high voltage alternating current
  • a device typically referred to as a power supply or as a power converter can be utilized in lighting systems to convert the high voltage ac input into a well regulated direct current (dc) output through an energy transfer element.
  • Switched mode power converters are commonly used due to their high efficiency, small size, and low weight to power many of today's electronics.
  • a switch included in a driver circuit of the power converter is utilized to provide the desired output by varying the duty cycle (typically the ratio of the on time of the switch to the total switching period), varying the switching frequency or varying the number of pulses per unit time of the switch in a power converter.
  • the switching frequency of a switched mode power converter is much greater than the line frequency of the high voltage ac input. In fact, the switching frequency may be orders of magnitudes greater than the line frequency.
  • a TRIAC dimmer circuit or a thyristor dimmer circuit, removes a portion of the ac input voltage to limit the amount of voltage and current supplied to an incandescent lamp.
  • phase dimming because it is often convenient to designate the position of the missing voltage in terms of a fraction of the period of the ac input voltage measured in degrees.
  • the ac input voltage is a sinusoidal waveform and the period of the ac input voltage is referred to as a full line cycle.
  • half the period of the ac input voltage is referred to as a half line cycle.
  • An entire period has 360 degrees, and a half line cycle has 180 degrees.
  • the phase angle is a measure of how many degrees (from a reference of zero degrees) of each half line cycle the dimmer circuit removes.
  • removal of half the ac input voltage in a half line cycle by a TRIAC dimmer circuit corresponds to a phase angle of 90 degrees.
  • removal of a quarter of the ac input voltage in a half line cycle may correspond to a phase angle of 45 degrees.
  • phase angle dimming works well with incandescent lamps that receive the altered ac line voltage directly, phase angle dimming typically creates problems for light emitting diode (LED) lamps driven by a switched mode power converter.
  • LED light emitting diode
  • Conventional regulated switched mode power converters are typically designed to ignore distortions of the ac input voltage and deliver a constant regulated output until a low input voltage causes them to shut off. As such, conventional regulated switched mode power converters cannot dim LED lamps. Unless a power converter for an LED lamp is specially designed to recognize and respond to the voltage from a TRIAC dimmer circuit in a desirable way, the dimmer circuit can produce unacceptable results such as flickering of the LED lamp.
  • a TRIAC dimmer circuit is a semiconductor component that behaves as a controlled ac switch. In other words, it behaves as an open switch to an ac voltage until it receives a trigger signal at a control terminal, which causes the switch to close. The switch remains closed as long as the current through the switch is above a value referred to as the holding current.
  • Most incandescent lamps use more than enough current from the ac power source to allow reliable and consistent operation of a TRIAC dimmer circuit.
  • the low current used by efficient power converters to drive LED lamps may not draw sufficient current to keep the dimmer circuit conducting for the expected portion of the ac line period.
  • a control circuit for use in a power converter that has a dimmer circuit coupled to an input of the power converter includes a current controller and a main controller.
  • the current controller controls a current through an energy transfer element of the power converter by cycling between a first and second states.
  • the main controller controls the current controller in a first mode where the first state of the current controller is an ON state and the second state is an OFF state such that an output of the power converter is regulated.
  • the main controller controls the current controller in a second mode where the first state is the ON state but the second state is a non-zero minimum current state to maintain an input current of the power converter that is equal to or greater than a holding current threshold of the dimmer circuit.
  • a power converter in another example, includes an energy transfer element and an integrated control circuit.
  • the integrated control circuit includes a current controller and a main controller.
  • the current controller controls a current through an energy transfer element of the power converter by cycling between a first and second states.
  • the main controller controls the current controller in a first mode where the first state of the current controller is an ON state and the second state is an OFF state such that an output of the power converter is regulated.
  • the main controller controls the current controller in a second mode where the first state is the ON state but the second state is a non-zero minimum current state to maintain an input current of the power converter that is equal to or greater than a holding current threshold of the dimmer circuit.
  • a main controller for use in a power converter includes a drive circuit, a phase detection circuit, and a linear control circuit.
  • the drive circuit generates a drive signal in response to a feedback signal representative of the output of the power converter.
  • the drive signal controls a power switch of a current controller of the power converter in either a first mode or in a second mode.
  • the phase detection circuit receives an input sense signal and generates a phase angle signal in response thereto.
  • the phase angle signal is representative of a phase angle of an input voltage of the power converter.
  • the linear control circuit generates a linear control signal which controls a controlled current source of the current controller of the power converter in response to the phase angle signal.
  • the linear control signal controls the controlled current source when in the second mode of operation.
  • the current controller is controlled in the first mode when the phase angle is less than a phase angle threshold and wherein the current controller is controlled in the second mode when the phase angle is greater than the phase angle threshold.
  • FIG. 1A is an example schematic diagram illustrating a power converter having a main controller coupled to receive an input sense signal representative of an input current of the power converter, in accordance with the teachings of the present disclosure.
  • FIG. IB is an example schematic diagram illustrating a power converter having a main controller coupled to receive an input sense signal representative of a dimmer output voltage of the power converter, in accordance with the teachings of the present disclosure.
  • FIG. 1C is an example schematic diagram illustrating a power converter having a main controller coupled to receive an input sense signal representative of rectified input voltage of the power converter, in accordance with the teachings of the present disclosure.
  • FIG. ID is an example schematic diagram illustrating a power converter having a main controller coupled to receive an input sense signal representative of an output current of the power converter, in accordance with the teachings of the present disclosure.
  • FIG. IE is an example schematic diagram illustrating a power converter having a main controller coupled to receive an input sense signal representative of an current through the energy transfer element of the power converter, in accordance with the teachings of the present disclosure.
  • FIGS. 2A-2C illustrate example waveforms of an ac voltage, a dimmer output voltage, and a rectified input voltage, in accordance with the teachings of the present disclosure.
  • FIGS. 3A-3D illustrate various example waveforms of the input current with respect to a phase angle of the input voltage operating in a first mode and a second mode, in accordance with the teachings of the present disclosure.
  • FIG. 4A illustrates a drain current of a current controller operating in a first mode of operation, in accordance with the teachings of the present disclosure.
  • FIG. 4B illustrates a drain current of a current controller operating in a second mode of operation, in accordance with the teachings of the present disclosure.
  • FIG. 4C illustrates drain current of a current controller operating in a third mode of operation, in accordance with the teachings of the present disclosure.
  • FIG. 5 is an example schematic diagram illustrating a power converter having a control circuit that includes a main controller and a current controller, in accordance with the teachings of the present disclosure.
  • FIG. 6 is an example functional block diagram illustrating a main controller, in accordance with the teachings of the present disclosure.
  • FIG. 7 is an example schematic diagram illustrating a power converter having a control circuit that includes a main controller and a current controller, in accordance with the teachings of the present disclosure.
  • FIG. 8 is an example functional block diagram illustrating a main controller, in accordance with the teachings of the present disclosure.
  • FIG. 9 is an example schematic diagram illustrating an isolated power converter, in accordance with the teachings of the present disclosure.
  • a TRIAC dimmer circuit is one example of a dimming circuit included in power supplies utilized in lighting applications.
  • the dimming circuit removes a portion of the ac input voltage to limit the amount of voltage and current supplied to a load (e.g., an incandescent lamp).
  • a load e.g., an incandescent lamp.
  • the load that is driven by a power converter includes an LED lamp, unless the power converter is specially designed to recognize and respond in a desirable way to a voltage having removed portions, the TRIAC dimmer circuit can produce unacceptable results such as flickering of the LED lamp.
  • LED lamps generally draw less current than incandescent lamps
  • the low current drawn by efficient power converters that drive LED lamps from the ac power source may not be enough current (i.e., the holding current) to keep a TRIAC dimmer circuit conducting for the expected portion of the ac line period.
  • the high frequency transition of the sharply increasing input voltage that occurs when the dimmer circuit fires during each half line cycle causes inrush input current ringing, which may drop below holding current.
  • a bleeder circuit may be utilized to keep the current through the TRIAC dimmer circuit above the holding current.
  • Conventional bleeder circuits may include a series damping resistor, which is coupled between the TRIAC dimmer circuit and the input of the power converter.
  • the series damping resistance conducts current (and therefore dissipates power) while a voltage is present. As such, use of a series damping resistance affects the efficiency of the overall power conversion system.
  • examples of power converters used in lighting systems with dimming circuitry may include a current controller that is coupled to control current through an energy transfer element of the power converter in order to regulate an output of the power converter.
  • Embodiments discussed herein control the current controller to operate in multiple modes of operation. In a first mode, the current controller may be controlled to cycle between an ON state and an OFF state. In response to detecting that the input current of the power converter will soon fall below a holding current threshold, the current controller may then be operated in a second mode of operation, where the current controller cycles between the ON state and a non-zero minimum current state. The non-zero minimum current state of the current controller maintains the input current of the power converter to be equal to or greater than the holding current threshold of the dimmer circuit.
  • FIG. 1A is an example schematic diagram illustrating a power converter 100 having a main controller 118 coupled to receive an input sense signal 140 that is representative of an input current l w 130 of the power converter 100, in accordance with the teachings of the present disclosure.
  • the illustrated example of power converter 100 includes a current controller 106, an input capacitor Cnsr 109, a diode Dl 110, an energy transfer element LI 108, and an output capacitor Co 112. Also shown in FIG. 1A are a dimmer circuit 102, a rectifier 104, a load 114, and a sense circuit 116.
  • the illustrated example of current controller 106 includes a switch 120 (e.g., a power switch) and a current source 122.
  • FIG. 1A illustrates power converter 100 configured as a buck converter
  • various other types of power converter topologies may be implemented in accordance with the teachings herein.
  • power converter 100 may configured as any switch mode power converter topology including, for example, flyback, forward, boost, buck, half bridge, and full bridge, among many others including resonant types.
  • power converter 100 provides power to load 114 from an unregulated input voltage.
  • the input voltage is an ac input voltage V AC 124.
  • dimmer circuit 102 receives ac input voltage V AC 124 to produce dimmer output voltage V DO 126.
  • the dimmer output voltage V DO 126 is received by the rectifier 104 to produce a rectified input voltage Vnsr 128.
  • rectifier 104 includes a full- wave rectifier circuit.
  • FIGS. 2A-2C illustrate example waveforms of an ac input voltage 224, a dimmer output voltage 226, and a rectified input voltage 228, in accordance with the teachings of the present disclosure.
  • Ac input voltage 224, dimmer output voltage 226, and rectified input voltage 228 are possible representations of ac input voltage 124, dimmer output voltage 126, and rectified input voltage 128, respectively, of FIG. 1A.
  • ac input voltage V AC 224 is generally a sinusoidal waveform with a period denoted as a full line cycle T A c 248.
  • a full line cycle T A c 248 of ac input voltage V AC 224 is denoted as the length of time between every other zero-crossing.
  • a full line cycle spans 360 degrees, with 180 degrees between zero crossings.
  • the half line cycle 250 of the ac input voltage V AC 224 is denoted as the length of time between consecutive zero-crossings.
  • the phase angle ⁇ 252 is measured as how many degrees (from a reference of zero degrees) the dimmer circuit 102 disconnects the input voltage V AC 224.
  • dimmer circuit 102 disconnects the ac input voltage V AC 224 from power converter 100 when the ac input voltage V AC 224 substantially crosses zero voltage.
  • the dimmer circuit 102 reconnects ac input voltage V AC 224 with power converter 100 and the dimmer output voltage V DO 226 substantially follows the ac input voltage V AC 224.
  • the dimmer circuit 102 removes a portion of the ac input voltage 224 to provide the dimmer output voltage V DO 226 thus limiting the amount of power supplied to a load (such as an LED lamp).
  • FIG. 2C illustrates that at the beginning of each half line cycle 250, rectified input voltage Vnsr 228 is substantially equal to zero, corresponding to the time that the dimmer circuit 102 disconnects the ac input voltage V AC 224 from the power converter.
  • dimmer output voltage V DO 226 sharply changes from zero to substantially follow the ac input voltage V AC 224 when dimmer circuit 102 reconnects the ac input voltage 224.
  • the illustrated embodiment of current controller 106 includes switch 120 and controlled current source 122.
  • Current controller 106 is coupled to the cathode of the diode Dl 110 and to one terminal of energy transfer element LI 108.
  • Energy transfer element LI 108 is further coupled to an output capacitor Co 112.
  • the output capacitor Co 112 is coupled to the output return 111 to provide an output voltage Vo 132 across the output capacitor 112.
  • the load 114 is coupled to the output capacitor Co 112.
  • the anode of diode Dl 110, output capacitor Co 112, and the load 114 are coupled to the output return 111.
  • Current controller 106 is also coupled to input capacitor Cnsr 109.
  • the input capacitor Cnsr 109 is coupled to the rectifier 104 such that the voltage across the input capacitor Cnsr 109 is the rectified input voltage V I 128.
  • Rectifier 104 is further coupled to dimmer circuit 102, which in one example may include a triac dimmer circuit 113.
  • Dimmer circuit 102 is coupled to receive the ac input voltage V AC 124.
  • switch current I sw may pass through the switch 120 to energy transfer element LI 108, thereby charging output capacitor Co 112 and providing power to load 114.
  • switch 120 is open (i.e., OFF state)
  • inductor current Ip continues through the energy transfer element LI 108, capacitor Co 112, and load 114.
  • the inductor current I P then returns through diode Dl 110, thereby ramping down while energy stored in energy transfer element 108 discharges.
  • Main controller 118 includes terminals for receiving and/or providing the input sense signal 140, switch current sense signal 142, switch drive signal U D
  • input sense 140 is representative of the input current l w 130.
  • switch current sense signal 142 received by main controller 118, is representative of the switch current Isw through switch 120.
  • Switch drive signal U D 144 is provided to control the switching of switch 120.
  • Main controller 118 is configured to output a linear control signal U LC 146 for controlling current source 122.
  • main controller 118 is also coupled to receive a feedback signal U FB 138, which, in this example, is received from sense circuit 116.
  • feedback signal U FB 138 is representative of the output of power converter 100.
  • sense circuit 116 may be coupled to receive an output quantity signal Uo 136 that is representative of the output of the power converter 100, which may be output voltage Vo 132, output current Io 134, or a combination of the two.
  • Main controller 118 may maintain the minimum holding current for the triac 113 to operate properly and regulate output power supplied to load 114.
  • Main controller 118 also regulates power to load 114 by controlling current controller 106 based on the feedback signal 138.
  • Switch 120 is controlled in response to the switch drive signal U D 144.
  • Main controller 118 controls the operation of the power converter 100 with switch drive signal 144 to regulate the power delivered to load 114.
  • the main controller 118 utilizes the current controller 106 to provide current such that the input current does not fall below the minimum holding current of dimmer circuit 102.
  • Main controller 118 receives input sense signal 140 and determines whether the input current 1 ⁇ 2 130 may be close to falling below the holding current threshold.
  • main controller 118 provides the linear control signal 146 which enables the controlled current source 122.
  • input current 1 ⁇ 2 130 is substantially equal to the sum of the linear current I LNR and the switch current Isw-
  • controlled current source 122 provides additional current I LNR which then increases the input current l w above the holding current.
  • controlled current source 122 provides a constant linear current I LNR -
  • controlled current source 122 provides a variable linear current I LNR that changes with changes in the input sense signal 140.
  • current source 122 may provide a linear current I LNR that is inversely proportional to the magnitude of the input sense signal 140.
  • Main controller 118 may control current controller 106 in multiple modes of operation.
  • a first mode includes cycling switch 120 between an ON state and an OFF state while controlled current source 122 is disabled, such that the controlled current source 122 does not provide additional current.
  • the drain current I D when in the first mode of operation, the drain current I D , may return to zero each time switch 120 turns off (i.e., OFF state).
  • main controller 118 may change to controlling current controller 106 in a second mode of operation.
  • the second mode of operation includes cycling switch 120 between the ON state and the OFF state while current source 122 is enabled to provide the linear current I LNR .
  • current source 122 is enabled to provide linear current I LNR , such that the input current I IN 130 is maintained at least above the holding current threshold of dimmer circuit 102.
  • the drain current I D is equal to the switch current I sw plus the linear current I L N R -
  • main controller 118 may control current controller 106 in multiple modes of operation.
  • current controller 106 may include a third mode of operation in addition to the first and second modes discussed above.
  • main controller 118 may control the current controller 106 in the third mode of operation in response to a light load at the output of the power converter.
  • the input voltage may be low or the load may be small such that there may be little to no benefit in using the switching element.
  • switch 120 is held in the OFF state and current source 122 is driven in a linear mode to provide enough holding current at the input of power converter 100.
  • the drain current ID is simply equal to the linear current ILNR-
  • FIG. IB is an example schematic diagram illustrating a power converter 101 having a main controller 1 18 coupled to receive input sense signal 140.
  • Power converter 101 couples and operates similar to power converter 100 discussed above.
  • main controller 1 18 was coupled to receive an input sense signal 140 that is representative of the input current l w 130 and main controller 1 18 determines the mode of operation of current controller 106 based on a magnitude of the input current 1 ⁇ 2.
  • input sense signal 140 is representative of dimmer output voltage VDO 126.
  • main controller 1 18 of FIG. IB may determine the mode of operation based on the dimmer output voltage VDO 126.
  • main controller 1 18 includes a phase detection circuit to determine the phase angle of the dimmer output voltage VDO 126. Main controller 1 18 of FIG. IB, may then compare the determined phase angle against a phase angle threshold in order to determine the mode of operation. In one embodiment, a measured phase angle below the phase angle threshold corresponds to the first mode of operation, while a phase angle at or above the phase angle threshold corresponds to the second mode of operation.
  • FIG. 1C is an example schematic diagram illustrating a power converter 103 having main controller 1 18 coupled to receive input sense signal 140, in this embodiment, that is representative of rectified input voltage Vnsr 128.
  • Power converter 103 couples and operates similar to power converter 100 discussed above.
  • input sense signal 140 is representative of rectified input voltage Vnsr 128.
  • main controller 1 18 of FIG. 1C may determine the mode of operation based on rectified input voltage Vnsr 128.
  • main controller 1 18 includes a phase detection circuit to determine the phase angle of the rectified input voltage Vnsr 128.
  • Main controller 1 18 of FIG. 1C may then compare the determined phase angle against a phase angle threshold in order to determine the mode of operation.
  • a measured phase angle below the phase angle threshold corresponds to the first mode of operation, while a phase angle at or above the phase angle threshold corresponds to the second mode of operation.
  • FIG. ID is an example schematic diagram illustrating a power converter 105 having a main controller 118 coupled to receive input sense signal 140, which in this embodiment is representative of an output current Io 134 of the power converter 105.
  • Power converter 105 couples and operates similar to power converter 100 discussed above.
  • input sense signal 140 is representative of output current Io 134.
  • main controller 118 of FIG. ID may determine the mode of operation based on a magnitude of output current Io 134.
  • output current I 0 is taken as the current through diode Dl 110.
  • the current through diode Dl 110 may be representative of an input (e.g., input current ITM 130) when switch 120 is not conducting (i.e., in the OFF state).
  • FIG. IE is an example schematic diagram illustrating a power converter 107 having main controller 118 coupled to receive input sense signal 140, which in this example is representative of an inductor current Ip through energy transfer element LI 108.
  • Power converter 107 couples and operates similar to power converter 100 discussed above.
  • input sense signal 140 is representative of inductor current I P .
  • main controller 118 of FIG. ID may determine the mode of operation based on a magnitude of inductor current Ip.
  • inductor current Ip through energy transfer element LI 108 may be representative of an input (e.g., input current l w 130) when switch 120 is conducting (i.e., in the ON state).
  • FIGS. 3A-3D illustrate various example waveforms of the input current 1 ⁇ 2 with respect to a phase angle of the input voltage operating in a first, second, and an optional third mode of operation, in accordance with embodiments of the present disclosure.
  • FIG. 3A illustrates waveforms of the input current 1 ⁇ 2 330 in a first and second mode of the current controller (e.g., current controller 106).
  • the vertical axis represents input current 1 ⁇ 2 330, while the horizontal axis represents the phase angle 352.
  • the phase angle 352 is a measure of how many degrees (from a reference of zero degrees) of each half line cycle the dimmer circuit removes the ac input voltage 124 from the power converter.
  • a first phase threshold is represented by ⁇ ⁇ 360.
  • FIG. 3A illustrates a thin dashed line representative of the switch current Isw and a thin solid line representative of the linear current I LNR .
  • the main controller may sense the phase angle of the triac to indirectly sense the input current.
  • the thick solid line is representative of the resultant input current ITM 330.
  • switch current I sw decreases due to the drop in available energy from dimmer circuit 102.
  • the current controller may operate in a first mode.
  • the input current is substantially equal to the switch current (shown as a dashed line) since the current controller is cycling between an ON state and an OFF state while the controlled current source is disabled such that the controlled current source is not providing additional current.
  • the input current 330 is shown as substantially following the switch current. As illustrated, the average input current decreases with an increasing phase angle.
  • phase threshold 360 Illustrated in FIG. 3A is a phase threshold 360 which is
  • the current controller may switch to operating in a second mode of operation.
  • the current controller cycles between the ON state and a non-zero minimum current state, such that the input current is substantially equal to the sum of the switch current Isw and the linear current I LNR -
  • the main controller controls the controlled current source such that the linear current increases I LNR as the phase angle increases.
  • the switch current Isw decreases at the same rate at which the linear current is increased, such that the resultant input current 1 ⁇ 2 is a constant value while the current controller in the second mode.
  • FIG. 3B illustrates waveforms of the input current l w 330 in a first and second mode of the current controller, in accordance with another embodiment of the present disclosure.
  • the main controller controls the controlled current source such that the linear current I LNR is
  • the input current 330 increases by the value of the linear current I LNR and then decreases at the same rate as the switch current decreases.
  • the linear current I LNR provides a fixed offset in the second mode of operation for the example shown in FIG. 3B.
  • the value of the linear current I LNR is substantially equal to the holding current I HOLD of the dimmer circuit.
  • FIG. 3C illustrates waveforms of the input current 1 ⁇ 2 330 in a first, second, and an optional third mode of the current controller, in accordance with another embodiment of the present disclosure.
  • the third mode of operation occurs in response to a light load.
  • phase angle 352 reaches the first phase threshold ⁇ 360
  • the current controller transitions from the first mode of operation to the second mode of operation.
  • current source 356 of the current controller 106 provides a linear current I LNR to the input current
  • the linear current I LNR is increased in response to increases in phase angle 352.
  • the current controller transitions to a third mode of operation.
  • Switch 120 In the third mode of operation, Switch 120 is open (i.e, OFF state) .
  • the input current is substantially equal to linear current I LNR , which is still increased in response to increases in phase angle 352. This indicates the current source is driven in linear mode to provide enough holding current to input current I IN 330 .
  • FIG. 3D illustrates waveforms of the input current 1 ⁇ 2 330 in a first, second, and optional third mode of the current controller.
  • the main controller controls the current source in the second and third modes of operation such that the linear current ILNR is substantially constant with an increasing phase angle 352.
  • the linear current I LNR provides a fixed offset for the example shown in FIG. 3D.
  • FIG. 4A illustrates a drain current I D 407 of a current controller operating in a first mode of operation, in accordance with the teachings of the present disclosure.
  • Drain current I D 407 is one possible representation of drain current I D of FIGS. 1A-1E.
  • the main controller is operating in discontinuous conduction mode (DCM).
  • the vertical axis denotes the drain current I D 407 while the horizontal axis represents time.
  • the switching period of each waveform is denoted by T s 470.
  • the on time period i.e., the time that current controller 106 is in the ON state each switching period Ts
  • T ON 472 The on time period (i.e., the time that current controller 106 is in the ON state each switching period Ts) is denoted by T ON 472.
  • the off time period (i.e., the time that current controller 106 is in the OFF state each switching period Ts) is denoted T 0FF 474.
  • switch 120 is cycled on and off while current source 122 is disabled, such that current source 122 does not provide additional current.
  • the drain current I D is equal to the switch current Isw-
  • switch current I sw increases.
  • switch current I sw decreases and substantially falls to zero.
  • FIG. 4B illustrates the drain current I D of a current controller operating in a second mode of operation, in accordance with the teachings of the present disclosure.
  • the main controller controls current source 122 to provide a constant current I LNR 423, while switch is cycled on and off.
  • the current controller 106 includes an ON state that is maintained for an on time period T ON 472.
  • the drain current I D is substantially equal to the switch current I sw plus the linear current I LNR 423.
  • current controller 106 also includes a non-zero minimum current state that is maintained for a minimum current time period T MIN J 474.
  • the drain current I D is still equal to the switch current Isw plus the linear current I LNR 423, but since the switch is off, the switch current Isw is substantially zero, thereby resulting in a drain current I D that is equal to the linear current I LNR 423.
  • the linear current I LNR 423 is added during the second mode of operation maintain the input current ITM of the power converter at or above a holding current of the dimmer circuit.
  • the magnitude of the linear current I LNR 423 is substantially equal to or greater than the minimum holding current requirements of the dimmer circuit (e.g., dimmer circuit 102).
  • FIG. 4C illustrates drain current I D of the current controller operating in a third mode of operation, in accordance with the teachings of the present disclosure.
  • the third mode of operation includes main controller 118 disabling switch 120, such that switch 120 is kept open and switch current I sw is substantially equal to zero.
  • main controller 118 enables current source 122 such that current controller 106 provides a current I LNR 423 that is equal to or greater than a minimum holding current requirement of the triac.
  • FIG. 5 is an example schematic diagram illustrating a power converter 500 having a control circuit 501 that includes a main controller 518 and a current controller 506, in accordance with the teachings of the present disclosure.
  • Power converter 500 couples and operates similar to power converter 100 discussed above.
  • main controller 118 provides separate control signals to switch 120 and controller current source 122.
  • main controller 518 provides a single combined drive signal U D /U LC 545 to current controller 506.
  • current controller 506 includes a metal oxide semiconductor field effect transistor (MOSFET) that functions as both a switch and a controlled current source.
  • MOSFET metal oxide semiconductor field effect transistor
  • main controller 518 when in the first mode of operation, main controller 518 generates combined drive signal U D U LC to cycle the MOSFET between an OFF state and an ON state, where the ON state includes driving the MOSFET to be fully on (e.g., in a saturation region of the MOSFET).
  • main controller 518 When in the second mode of operation, main controller 518 generates combined drive signal U D /U LC to cycle the MOSFET between the ON state and a non-zero minimum current state, where the non-zero minimum current state includes driving the MOSFET to be partially on (e.g., in a linear region of the MOSFET).
  • Input sense signal 540 can be represented by any of the embodiments mentioned previously with regards to FIGS. 1A-1E. As shown in the example of FIG. 5, main controller 518 and current controller 506 may be combined onto a single integrated circuit 501.
  • FIG. 6 is an example functional block diagram illustrating a main controller 618, in accordance with the teachings of the present disclosure.
  • Main controller 618 is one possible implementation of main controller 518 of FIG. 5.
  • the illustrated example of main controller 618 includes a phase detection 676, reference generator 678, error amplifier 684, linear control circuit 680, and drive circuit 686.
  • Main controller 618 includes terminals for the input sense signal 640, switch current sense signal 642, switch drive signal U D 645, and feedback signal U FB 638.
  • Phase detection 676 is coupled to receive the input sense signal 640.
  • the phase detection circuit 676 determines the phase angle from the input sense signal 640 and outputs a phase angle signal 652.
  • the phase angle signal 652 is representative of the phase angle of the dimmer circuit at the input of the power converter.
  • Reference generator 678 and linear control circuit 680 are coupled to receive the phase angle signal 652.
  • the reference generator output signal changes with respect to changes in the phase angle.
  • Reference generator 678 is coupled to the inverting terminal of the error amplifier 684.
  • the output of reference generator 678 is coupled to be received by the inverting terminal of the error amplifier 684.
  • error amplifier 684 may be a comparator that compares the reference signal 682 with the feedback signal 638.
  • the non-inverting terminal of the error amplifier 684 is coupled to receive the feedback signal U FB 638.
  • the output of the error amplifier 684 is coupled to the drive circuit 686.
  • Drive circuit 686 is coupled to receive both the switch current sense 642 signal and the linear control circuit signal 646.
  • Drive circuit 686 generates a drive signal 645 in response to the output of error amplifier 684, linear control signal 646, and switch current sense signal 642.
  • Linear control circuit 680 is coupled to receive the phase angle signal 652.
  • linear control circuit 680 may also receive the feedback signal U FB 638 to compare in conjunction with phase angle 652.
  • the linear control signal 646 sets the value at which to drive the switch to maintain the minimum input holding current based on phase angle 652.
  • Linear control circuit 680 can also control the output current I 0 by keeping it proportional to the phase dimming angle based on the feedback signal U FB 638.
  • Phase detection 676 determines the phase angle from the input sense signal 640 and provides the phase angle signal 652 for the reference generator 678 and linear control circuit 680.
  • Reference generator 678 generates a reference voltage U REF 682 based on the phase angle provided by the phase angle signal 652.
  • Error amplifier 684 outputs an error voltage from the reference generator and feedback signal U FB 638. Based on the error voltage, the drive circuit 686 varies the drive signal U D 645 to regulate the output.
  • the changes in drive signal U D 645 may include but not limited to, the on/off time, frequency, and duty cycle.
  • FIG. 7 is an example schematic diagram illustrating a power converter 700 having a control circuit 701 that includes a main controller 718 and a current controller 706, in accordance with the teachings of the present disclosure.
  • Power converter 700 couples and operates similar to power converter 100 discussed above.
  • this example of current controller 706 includes a MOSFET switch 720 and a controlled current source (i.e., MOSFET 790 and JFET 788).
  • JFET 788 is coupled to MOSFET 790, where the JFET includes a control terminal coupled to the common reference of the current controller.
  • the JFET 788 is an example of a current source to power converter 700.
  • the JFET 788 is one embodiment that provides the minimum holding current for the triac.
  • the linear current may be a constant value.
  • the linear current is proportional to changes in the phase angle.
  • the embodiment of FIG. 7 may reduce the dependence of an external bleeder circuit to take enough extra current from the input of the power supply to keep the triac conducting.
  • An external bleeder circuit may be undesirable because the bleeder circuit would dissipate energy (in the form of heat) and require the use of extra components with associated penalties in cost and efficiency.
  • aspects of the present invention discussed herein reduce the overall amount of components required. Accordingly, embodiments of the present disclosure provide the required amount of current, as needed, to maintain proper operation of the triac, while also regulating the output of the power converter, without the need for external components, such as a bleeder circuit.
  • FIG. 8 is an example functional block diagram illustrating a main controller 818, in accordance with the teachings of the present disclosure.
  • Main controller 818 is one possible implementation of main controller 718 of FIG. 7.
  • Main controller 818 operates and couples similar to main controller 618, discussed above, except that main controller 818 generates a drive signal 844 that is separate and distinct from a generated linear control signal 846.
  • Phase detection 876 is coupled to receive the input sense signal 840.
  • Reference generator 878 and linear control circuit 880 are coupled to receive the phase angle signal 852.
  • Reference generator 878 is coupled to the inverting terminal of the error amplifier 884.
  • the non-inverting terminal of the error amplifier 884 is coupled to receive the feedback signal L1 ⁇ 2 838.
  • the output of the error amplifier 884 is coupled to the drive circuit 686.
  • Drive circuit 886 is also coupled to receive the switch current sense 842 signal and linear control circuit signal 846.
  • Drive circuit 886 generates a drive signal 844.
  • Linear control circuit 880 receives the feedback signal U FB 838.
  • FIG. 9 is an example schematic diagram illustrating an isolated power converter 900, in accordance with the teaching of the present disclosure.
  • FIG. 9 illustrates an embodiment of main controller 918 and current controller 906 incorporated into a power converter 900 having flyback power converter topology.
  • This illustrated example of power converter 900 includes current controller 906, energy transfer element 908, input return 911, output capacitor CI 912, output diode Dl 915, sense circuit 916, output return 917, main controller 918, and clamp 919.
  • Energy transfer element 908 is shown as including a primary winding 909 and a secondary winding 913.
  • Current controller 906 is shown as including a switch 920 and a controlled current source 922.
  • load 914 coupled to the output of power converter 900.
  • load 914 includes one or more light emitting diodes (LEDs).
  • LEDs light emitting diodes
  • the power converter 900 utilizes the energy transfer element Tl 908 to transfer voltage between the primary 909 and the secondary 913 windings.
  • the clamp circuit 919 is coupled to the primary winding 909 to limit the maximum voltage.
  • Switch 920 is opened and closed in response to the drive signal 944. It is generally understood that a switch that is closed may conduct current and is considered on, while a switch that is open cannot conduct current and is considered off.
  • the switch SI 920 may be a transistor such as a metal-oxide- semiconductor field-effect transistor (MOSFET).
  • main controller 918 may be implemented as a monolithic integrated circuit or may be implemented with discrete electrical components or a combination of discrete and integrated components.
  • the switching of the switch 920 produces a pulsating current at the rectifier Dl 915.
  • the current in the rectifier Dl 915 is filtered by the output capacitor CI 912 to produce a substantially constant output voltage Vo 932, output current I 0 934, or a combination of the two at the load 914.
  • the power converter 100 further comprises circuitry to regulate the output which is exemplified as output quantity Uo 936.
  • the sense circuit 916 may sense the output quantity Uo 936 from an additional winding (not shown) included in the energy transfer element Tl 908.
  • the galvanic isolation could be implemented by using devices such as an opto-coupler, a capacitor or a magnetic coupling.
  • the sense circuit 916 senses the output quantity Uo 934 of the power converter 900 to provide the feedback signal U FB 938 to the main controller 918.
  • the feedback signal U FB 938 may be a voltage signal or a current signal and provides information regarding the output quantity Uo 936 to the main controller 918.
  • the main controller 918 receives the switch current sense input signal 942 which relays the switch current Isw in the switch 920.
  • the main controller 918 may receive the input sense signal 940.
  • Input sense signal 940 can be represented by any of the embodiments mentioned previously with regards to FIGS. 1A-1E.
  • Main controller 918 may maintain the minimum holding current for the triac to operate properly and regulate output power supplied to load 914.
  • Main controller 918 controls current controller 906 in a similar manner as described in FIGS. 1A-1E.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

L'invention concerne un circuit de commande utilisable dans un convertisseur de puissance qui a un circuit atténuateur couplé à une entrée du convertisseur de puissance et qui comprend un régulateur de courant et un régulateur principal. Le régulateur de courant régule un courant au moyen d'un élément de transfert d'énergie du convertisseur de puissance en alternant cycliquement entre un premier état et un second état. Le régulateur principal commande le régulateur de courant dans un premier mode où le premier état du régulateur de courant est à un état actif et le second état est à un état inactif de sorte qu'une sortie du convertisseur de puissance est régulée. Le régulateur principal commande le régulateur de courant dans un second mode où le premier état est l'état actif et le second état est un état de courant minimal non nul pour maintenir un courant d'entrée du convertisseur de puissance qui est supérieur ou égal à un seuil de courant de maintien du circuit atténuateur.
PCT/US2014/023741 2013-03-12 2014-03-11 Régulateur de courant intégré permettant d'entretenir un courant de maintien d'un circuit atténuateur Ceased WO2014159456A1 (fr)

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US61/777,339 2013-03-12

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12227086B2 (en) 2021-02-18 2025-02-18 Power Integrations, Inc. Active discharge of an electric drive system
US12323052B2 (en) 2021-02-18 2025-06-03 Power Integrations, Inc. Active discharge of an electric drive system

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US20080018261A1 (en) * 2006-05-01 2008-01-24 Kastner Mark A LED power supply with options for dimming
WO2011042510A2 (fr) * 2009-10-07 2011-04-14 Lemnis Lighting Patent Holding B.V. Système d'éclairage à gradation d'intensité
US20110241557A1 (en) * 2009-10-26 2011-10-06 Light-Based Technologies Incorporated Holding current circuits for phase-cut power control
US20120280629A1 (en) * 2010-04-20 2012-11-08 Power Integrations, Inc. Dimming control for a switching power supply
US20130049622A1 (en) * 2011-08-31 2013-02-28 Power Integrations, Inc. Load current management circuit

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Publication number Priority date Publication date Assignee Title
US20080018261A1 (en) * 2006-05-01 2008-01-24 Kastner Mark A LED power supply with options for dimming
WO2011042510A2 (fr) * 2009-10-07 2011-04-14 Lemnis Lighting Patent Holding B.V. Système d'éclairage à gradation d'intensité
US20110241557A1 (en) * 2009-10-26 2011-10-06 Light-Based Technologies Incorporated Holding current circuits for phase-cut power control
US20120280629A1 (en) * 2010-04-20 2012-11-08 Power Integrations, Inc. Dimming control for a switching power supply
US20130049622A1 (en) * 2011-08-31 2013-02-28 Power Integrations, Inc. Load current management circuit

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12227086B2 (en) 2021-02-18 2025-02-18 Power Integrations, Inc. Active discharge of an electric drive system
US12323052B2 (en) 2021-02-18 2025-06-03 Power Integrations, Inc. Active discharge of an electric drive system

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