TWM535439U - LED dimmer circuit device - Google Patents

Abstract

The invention provides an LED dimmer circuit device, which comprises a bridge rectifier, an initial power supply circuit, a storage circuit, a switch circuit, and a controller. The bridge rectifier is connected to a light source to rectify the current outputted from the light source so as to generate a high voltage DC power. The initial power supply circuit is connected to the bridge rectifier for receiving the high voltage DC power to provide a temporary DC voltage at the initialization stage of the LED dimmer circuit device. The storage circuit is connected to the initial power supply circuit to store the power of the temporary DC voltage. The switch circuit is connected to the bridge rectifier to adjust the brightness of the light source according to on/off state of the switch circuit. The controller is coupled to the switch circuit to turn off the switch circuit in a fixed period and then turn on the switch circuit for adjusting the brightness of the light source.

Description

Dimming circuit device for light emitting diode

The present invention relates to the technical field of light-emitting diodes, and more particularly to a light-emitting diode device for a light-emitting diode.

Due to advances in semiconductor manufacturing, many lighting devices are now being replaced by light-emitting diodes (LEDs). In the past, people were free to adjust the brightness of the light according to environmental changes and personal preferences, while also reducing the consumption of electricity. Most of the lighting devices in the home have been equipped with dimmers. Therefore, when the LED lamp is to replace the traditional dimming incandescent lamp, it is necessary to take into account the user who has already installed the dimmer, so that the user feels that the LED lamp is also used like an incandescent lamp, and the brightness can be adjusted at will, and the dimming process is not Any exceptions will occur.

Dual-adaptive controllable dimmers (TRIAC) are often used for brightness adjustment of light-emitting diodes (LEDs). Figure 1 is a circuit diagram of a conventional triac dimmer (TRIAC). As shown in FIG. 1, it includes a potentiometer R1, a fixed resistor R2, a capacitor C1, a bidirectional trigger switch DIAC, and a bidirectional controllable dimming device (TRIAC). The RC network consists of R1, R2 and C1. When the mains supply 110 is turned on, the current will be charged through R1 and R2 and then into C1. When the C1 voltage reaches the trigger voltage of the DIAC, the bidirectional trigger switch DIAC turns on, then the TRIAC dimmer is triggered to turn on, and begins to supply power to the light emitting diode (LED) 120.

The potentiometer R1 needle moves downward (R1 resistance becomes larger), the current flowing through C1 decreases, the voltage on C1 will slower to reach the trigger voltage of DIAC, and the TRIAC will be triggered to be slower. As a result, the input sinusoidal voltage is cut off a part, resulting in a decrease in the energy supplied to the light emitting diode (LED) 120 (lower brightness). The higher the resistance of R1, the lower the brightness of the bulb.

2A and 2B are voltage waveform diagrams of a conventional TRIAC dimmer. As shown in FIG. 2A, it is a full sinusoidal voltage waveform diagram of the mains power supply 110 or the input end of the light emitting diode (LED) 120. 2B is a voltage waveform across the light emitting diode (LED) 120 after being intercepted by a TRIAC dimmer.

For TRIAC dimmable light emitting diodes (LEDs) 120, the biggest problem at present is the compatibility of the dimmer LEDs 120. The original design of traditional TRIAC dimmers was to handle the power consumed by hundreds of watts of incandescent bulbs. A light-emitting diode (LED) 120 that consumes less than 20 W will interact with a dimmer composed of a high-power switching device. And it produces flicker.

When the brightness of the light-emitting diode (LED) 120 is low (ie, Iled is very low), the input current at the mains terminal (ie, the current flowing through the TRIAC) will be small and less than Ihold, at which point the TRIAC dimmer will turn off. Then the mains charges C1. When the voltage of C1 reaches the triggering voltage of DIAC, the conduction of DIAC causes the TRIAC to turn on again, and the LED 120 becomes bright again. However, the Iled is low, the current flowing through the TRIAC is less than Ihold. The TRIAC is turned off again, and the light-emitting diode (LED) 120 is extinguished again. This cycle will cause the light-emitting diode (LED) 120 to flicker. In order to prevent flicker, the current flowing through the TRIAC dimmer during the turn-on of the TRIAC dimmer is greater than the TRIAC dimmer's holding current (Ihold), otherwise the TRIAC will turn off and the LED ( LED) 120 will go out.

In order to prevent the light-emitting diode (LED) 120 from flickering, the current flowing through the TRIAC dimmer must be greater than the holding current (Ihold). If the brightness of the light-emitting diode (LED) 120 is low, the current required is less than maintained. At current (Ihold), an additional circuit needs to be designed to allow the current flowing through the additional circuit (Ibleeder) plus the current flowing through the light-emitting diode (LED) 120 (Iled) to be greater than the holding current (Ihold), then The TRIAC will remain on and the LED bulb will not flash. This extra circuit consumes power and reduces power efficiency. .

The purpose of this creation is mainly to provide a dimming circuit device for a light-emitting diode, which can avoid the problem of flickering caused by the use of a two-way controllable dimmer. Due to the use of digital control, the brightness of the light source can be adjusted more linearly.

According to one of the features of the present invention, the present invention proposes a dimming circuit device for a light emitting diode, comprising a rectifying circuit, an initial power supply circuit, a storage circuit, a switch, and a controller. The rectifier circuit is coupled to a source of alternating current power to rectify the alternating current to a high potential DC power source. The initial power supply circuit is coupled to the rectifier circuit and receives the high potential DC power source to provide a temporary DC voltage when the dimming circuit device is activated. The tank circuit is connected to the initial power supply circuit, receives the temporary DC power source and stores energy. The switch is connected to the rectifier circuit, and the switch is turned on and off to adjust the brightness of the light source. The controller is coupled to the switch to adjust the waveform of the power source flowing through the light source according to an external input to turn off the switch for a fixed time, and then adjust the brightness of the light source.

FIG. 3 is a circuit diagram of a dimming circuit device 300 of the present invention. The dimming circuit device 300 of the LED includes a rectifying circuit 310, an initial power supply circuit 320, a tank circuit 330, a switch 340, a controller 350, and a first DC to DC converter 360. A steady state power switch circuit 370, a second DC to DC converter 380, a synchronous voltage dividing circuit 390 and an input device 395.

The rectifier circuit 310 is coupled to a source 301 powered by an alternating current to rectify the alternating current flowing through the source 301 into a high potential DC power source. The light source 301 is a light emitting diode (LED). One end of the light source 301 is connected to one end L of the mains, and the other end is connected to the rectifying circuit 310.

The rectifier circuit 310 is a bridge rectifier, and the rectifier circuit 310 includes first to fourth diodes D1-D4. The cathode of the first diode D1 is connected to the light source 301. The anode of the second diode D2 is connected to the light source 301, and the cathode thereof is connected to a first end point A. The anode of the fourth diode D4 is connected to the other end N of the mains, and its cathode is connected to the first end point A. The cathode of the third diode D3 is connected to the other end N of the mains, and its anode is connected to the anode of the first diode D1.

The initial power supply circuit 320 is coupled to the rectifier circuit 310 and receives the high potential DC power source to provide a temporary DC voltage when the dimming circuit device 300 is activated. The initial power supply circuit 320 includes a fifth diode D5, a first resistor R1, a second resistor R2, a first transistor T1, and a first capacitor C1.

The anode of the fifth diode D5 is connected to the first terminal A, and the cathode thereof is connected to one end of the first resistor R1 and the emitter of the first transistor T1. The other end of the first resistor R1 is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to a low potential Gnd. The base of the first transistor T1 is connected to one end of the first capacitor C1 and the other end of the first resistor R1, and a collector is connected to one end of the second resistor R2.

The tank circuit 330 is coupled to the initial power supply circuit 320, receives the temporary DC power source and stores energy. The energy storage circuit 330 includes a first senser diode Z1 and a second capacitor C2. The cathode of the first gated diode Z1 is connected to the other end of the second resistor R2, and its anode is connected to the low potential Gnd. One end of the second capacitor C2 is connected to the other end of the second resistor R2, and the other end thereof is connected to the low potential Gnd. The first register diode Z1 mainly embeds the temporary DC voltage of a second terminal B at a first voltage, and the first voltage is preferably 5-10 volts.

The switch 340 is connected to the rectifier circuit 310, and the switch 310 is turned on and off to adjust the brightness of the light source. The switch 340 includes a second transistor T2 and a third resistor R3. The second transistor T2 is preferably an insulated gate bipolar transistor (IGBT) having a collector connected to the first terminal A and an emitter connected to one end of the third resistor R3. The other end of the third resistor R3 is connected to the low potential Gnd. The second transistor T2 can also be a power component such as a MOSFET.

The controller 350 is coupled to the switch 340, and according to an external input, after the switch 340 is turned off for a fixed time, the switch 340 is turned on, thereby adjusting the waveform of the power flowing through the light source 301, and adjusting the light source. brightness. A pin P1 of the controller 350 is connected to the switch 340 via a seventh resistor R7, a fourth transistor T4, and an eighth resistor R8.

The first DC to DC converter 360 is coupled to the initial power supply circuit 320 and the tank circuit 330 to convert the temporary DC voltage into an operating DC voltage suitable for the controller 350. The operating DC voltage of the controller 350 is preferably 5 volts.

The steady state power switch circuit 370 is coupled to the rectifier circuit 310 and the controller 350. The controller 350 turns the switch 340 on and then turns the steady state power switch circuit 370 on to provide a steady state DC voltage.

The steady state power switch circuit 370 includes a sixth diode D6, a fourth resistor R4, a third transistor T3, and a second gate diode Z2. The anode of the sixth diode D6 is connected to the first terminal A, and the cathode thereof is connected to one end of the fourth resistor R4 and the emitter of the third transistor T3. The other end of the fourth resistor R4 is connected to the base of the third transistor T3 and a pin P2 of the controller 350. The collector of the third transistor T3 is connected to the cathode of the second arrester diode Z2. The anode of the second gated diode Z2 is connected to the low potential Gnd.

The second DC to DC converter 380 is coupled to the tank circuit 330 and the steady state power switch circuit 370 to boost the steady state DC voltage to the temporary DC voltage and to the tank circuit 330.

The synchronous voltage dividing circuit 390 is connected to the rectifying circuit 310, the initial power supply circuit 320, and the controller 350. The controller 350 is configured to detect the phase of the high-potential DC power supply according to the synchronous voltage dividing circuit 390. . The synchronous voltage dividing circuit 390 includes a fifth resistor R5 and a sixth resistor R6. One end of the fifth resistor R5 is connected to the first end point A, and the other end is connected to one end of the sixth resistor R6 and a pin P3 of the controller 350. One end of the sixth resistor R6 is connected to the low potential Gnd.

The input device 395 is connected to the controller 350. The controller 350 turns off or turns on the switch 340 according to the input of the input device 395, thereby adjusting the waveform of the power source flowing through the light source, and adjusting the brightness of the light source. The input device 395 is comprised of buttons 396, 397. In other embodiments, the input device 395 can be an infrared receiving device to receive an infrared control signal transmitted by an infrared remote controller (not shown). The input device 395 can also be a radio frequency receiving device for receiving a radio frequency control signal transmitted by a radio frequency remote controller (not shown). The radio frequency receiving device can be a Bluetooth radio frequency receiving device for receiving a Bluetooth control signal transmitted by a Bluetooth remote control (not shown).

Initially, due to rectification of rectifier circuit 310, the potential of first terminal A can be considered a high potential DC voltage, which is approximately one hundred volts. Therefore, the fifth diode D5 is turned on, and the first transistor T1 is also turned on. Current flows through the second resistor R2 and charges the second capacitor C2. At the same time, current flows through the first resistor R1 and charges the first capacitor C1.

Since the first capacitor C1 is charged, the voltage of the third terminal C gradually rises, causing the base voltage of the first transistor T1 to be close to its emitter voltage, so after charging the first capacitor C1 for a period of time, the first power The crystal T1 will turn off. Since the second capacitor C2 has been previously charged, the controller 350 is powered by the second capacitor C2 via the first DC to DC converter 360.

When the controller 350 completes initialization, it will set the pin P2 to a low potential, so the third transistor T3 will be turned on. Therefore, the second DC to DC converter 380 boosts the steady state DC voltage at the fourth terminal point D to the temporary DC voltage and stores it in the tank circuit 330. That is, after the first transistor T1 is turned off, the second capacitor C2 is charged by the steady state power switch circuit 370 and the second DC to DC converter 380. Since the first voltage of the second terminal B is preferably 5-10 volts, the switch 340 is turned on. After the switch 340 is turned on, the voltage of the first terminal A is lowered. Therefore, when the third transistor T3 is turned on, the second register diode Z2 and the second DC-to-DC converter 380 are not used. cause some damages.

When a user wants to adjust the brightness, when the button 397 is pressed down, the switch 340 sets the pin P1 to a high level for a certain period of time. The specific time is preferably one millisecond (ms). Since the pin P1 is at a high potential, the fourth transistor is turned on, and the voltage of the fifth terminal E is made low, causing the second transistor T2 to be turned off. Thereby, the current loop between the second diode D2 and the third diode D3 is turned off, thereby lowering the brightness of the light source 301.

When the second transistor T2 is turned off, the potential of the first terminal A rises to more than one hundred volts. Therefore, before the controller 350 turns off the switch 340, the controller 350 first sets the pin P2 to a high potential to turn off the steady state power switch circuit 370 to protect the steady state power switch circuit 370 and the second. DC to DC converter 380.

After one millisecond (ms), the controller 350 first sets the pin P1 to a low level to turn on the second transistor T2, and then turns on the steady state power switch circuit 370. In the meantime, the steady state power switch circuit 370 is turned off, but the second capacitor C2 will still supply power to the controller 350 due to energy storage.

In other embodiments, the controller 350 can set the second transistor T2 to have a 50% duty cycle during a duty cycle. When a user presses the button 396, the controller 350 increases the second power. The crystal T2 is turned on. When the user presses the button 397, the controller 350 reduces the on-time of the second transistor T2, thereby adjusting the brightness of the light source 301.

Since the clocks of the existing controllers are all tens or even hundreds of MHz, the ON time of the controller 350 for the second transistor T2 can be controlled quite accurately. Therefore, the controller 350 can generate a fairly linear response to the user pressing the buttons 396, 397, that is, the user can adjust the brightness of the light source 301 in a linear manner.

As can be seen from the foregoing description, the problem of flickering caused by the use of a bidirectional controllable dimming device (TRIAC) can be avoided in this case. There is also no need to design an extra circuit to prevent flicker. At the same time, the digital control mode can be used to make the brightness adjustment of the light source 301 more linear.

The above-described embodiments are merely examples for convenience of description, and the scope of the claims is intended to be limited to the above embodiments.

R1‧‧‧ potentiometer
R2‧‧‧ resistance
C1‧‧‧ capacitor
DIAC‧‧‧bidirectional trigger switch
TRIAC‧‧‧Two-way controllable dimmer
300‧‧‧Photodiode dimming circuit device
310‧‧‧Rectifier circuit
320‧‧‧Initial power supply circuit
330‧‧‧ Energy storage circuit
340‧‧‧Switcher
350‧‧‧ Controller
360‧‧‧First DC to DC Converter
370‧‧‧ Steady-state power switch circuit
380‧‧‧Second DC to DC converter
390‧‧‧Synchronous voltage divider circuit
395‧‧‧ Input device
One end of L‧‧‧ utility
N‧‧‧ The other end of the mains
D1-D4‧‧‧first to fourth diodes
A‧‧‧first endpoint
D5‧‧‧ fifth diode
R1‧‧‧first resistance
R2‧‧‧second resistance
T1‧‧‧first transistor
C1‧‧‧first capacitor
Gnd‧‧‧ low potential
Z1‧‧‧First Jenus diode
C2‧‧‧second capacitor
Vdd‧‧‧High potential
Gnd‧‧‧Grounding
B‧‧‧second endpoint
T2‧‧‧second transistor
R3‧‧‧ third resistor
P1-P5‧‧‧ pin
R7‧‧‧ seventh resistor
T4‧‧‧ fourth transistor
R8‧‧‧ eighth resistor
D6‧‧‧ sixth diode
R4‧‧‧fourth resistor
T3‧‧‧ third transistor
Z2‧‧‧Second-Secondary
R5‧‧‧ fifth resistor
R6‧‧‧ sixth resistor
396, 397‧‧‧ button
C‧‧‧ third endpoint
D‧‧‧ fourth endpoint
E‧‧‧ fifth endpoint

Figure 1 is a circuit diagram of a conventional triac dimmer (TRIAC). 2A and 2B are voltage waveform diagrams of a conventional TRIAC dimmer. 3 is a circuit diagram of a dimming circuit device of a light-emitting diode of the present invention.

300‧‧‧Photodiode dimming circuit device

310‧‧‧Rectifier circuit

320‧‧‧Initial power supply circuit

330‧‧‧ Energy storage circuit

340‧‧‧Switcher

350‧‧‧ Controller

360‧‧‧First DC to DC Converter

370‧‧‧ Steady-state power switch circuit

380‧‧‧Second DC to DC converter

390‧‧‧Synchronous voltage divider circuit

395‧‧‧ Input device

One end of L‧‧‧ utility

N‧‧‧ The other end of the mains

D1-D4‧‧‧first to fourth diodes

A‧‧‧first endpoint

D5‧‧‧ fifth diode

R1‧‧‧first resistance

R2‧‧‧second resistance

T1‧‧‧first transistor

C1‧‧‧first capacitor

Gnd‧‧‧ low potential

Z1‧‧‧First Jenus diode

C2‧‧‧second capacitor

Vdd‧‧‧High potential

Gnd‧‧‧Grounding

B‧‧‧second endpoint

T2‧‧‧second transistor

R3‧‧‧ third resistor

P1-P5‧‧‧ pin

R7‧‧‧ seventh resistor

T4‧‧‧ fourth transistor

R8‧‧‧ eighth resistor

D6‧‧‧ sixth diode

R4‧‧‧fourth resistor

T3‧‧‧ third transistor

Z2‧‧‧Second-Secondary

R5‧‧‧ fifth resistor

R6‧‧‧ sixth resistor

396,397‧‧‧ buttons

C‧‧‧ third endpoint

D‧‧‧ fourth endpoint

E‧‧‧ fifth endpoint

Claims (10)

A dimming circuit device for a light emitting diode, comprising: a rectifying circuit connected to a light source powered by an alternating current to rectify the alternating current into a high potential DC power source; an initial power supply circuit connected to the rectifying circuit Receiving the high-potential DC power source to provide a temporary DC voltage when the dimming circuit device is activated; a tank circuit connected to the initial power supply circuit, receiving the temporary DC power source and storing energy; a switcher connected to The rectifier circuit adjusts the brightness of the light source by turning on and off the switch; and a controller coupled to the switch to turn off the switch for a fixed time according to an external input, and then turn on The switch adjusts the waveform of the power source flowing through the light source to adjust the brightness of the light source. The dimming circuit device of the light emitting diode according to claim 1, further comprising: a first DC to DC converter connected to the initial power supply circuit and the energy storage circuit to The temporary DC voltage is converted into an operating DC voltage suitable for the controller. The dimming circuit device of the light-emitting diode according to claim 1, further comprising: a steady-state power switch circuit connected to the rectifier circuit and the controller, wherein the controller turns on the switch The steady state power switch circuit is further turned on to provide a steady state DC voltage; and a second DC to DC converter is coupled to the tank circuit and the steady state power switch circuit to boost the steady state DC voltage The temporary DC voltage is applied to the tank circuit. The dimming circuit device of the light emitting diode according to claim 3, wherein the controller turns off the steady state power switch circuit to protect the steady state power switch before the switch is turned off. The circuit and the second DC to DC converter. The dimming circuit device of the light emitting diode according to claim 1, further comprising: a synchronous voltage dividing circuit connected to the rectifying circuit, the initial power supply circuit, and the controller, the control According to the synchronous voltage dividing circuit, the phase of the high-potential power source is detected; and an input device is connected to the controller, and the controller turns off or turns on the switch according to the input of the input device, thereby The waveform of the power source flowing through the light source is adjusted, and the brightness of the light source is adjusted. The dimming circuit device of the light emitting diode according to the first aspect of the invention, wherein the rectifying circuit comprises first to fourth diodes. The dimming circuit device of the light emitting diode according to claim 1, wherein the initial power supply circuit comprises a fifth diode, a first resistor, a second resistor, and a first transistor. , a first capacitor. The dimming circuit device of the light emitting diode of claim 1, wherein the energy storage circuit comprises a first arrester diode and a second capacitor. The dimming circuit device of the light emitting diode according to the first aspect of the invention, wherein the switch comprises a second transistor and a third resistor. The dimming circuit device of the light emitting diode according to the fourth aspect of the invention, wherein the steady state power switch circuit comprises a sixth diode, a fourth resistor, a third transistor, and a first Ergena diode.