WO2018151052A1 - Non-voltage-dropping power supply circuit and application circuit - Google Patents

Abstract

[Problem] In order to form an electronic switch for intermittently switching a commercial power supply using a power MOSFET, a drive power, although very small, is required and therefore a conventional circuit configuration has had the disadvantage of, for example, consuming power even during no-load time. Although a highly efficient rectification scheme using the power MOSFET exists, the scheme separately requires drive power and therefore cannot be treated as a two terminal diode. Accordingly, a simple method for obtaining a very small power for controlling ten and several volts has been desired. [Solution] Provided are a non-voltage-dropping power supply circuit, an electronic switch using a power MOSFET, and an ideal diode capable of being treated as a two terminal. The non-voltage-dropping power supply circuit can obtain a very small power without causing a voltage drop in such a way that: a resistor having a high resistance is connected to the gate of a depletion-type FET to cause an operation delay; and instantaneous charging is performed when the power supply voltage reaches a required voltage.

Description

Non-voltage drop type power supply circuit and its application circuit

The present invention relates to a method of configuring an electronic circuit and its application circuit that obtains a minute DC power by avoiding a voltage drop accompanying power consumption from a power source that changes in voltage.

When a commercial power source is to be electrically controlled, a very small amount of power is required. However, in the configuration of a generally used power supply circuit, the number of parts increases, power efficiency is low, and standby power is completely zero. I couldn't.
Since the rectifying Schottky barrier diode has a forward voltage drop of 0.3 to several volts, about 1% of the power handled is heat.
There is a circuit configuration method for reducing the forward voltage from 1/10 to 1/100 using a power MOSFET or the like, called an “ideal diode” that reduces the forward voltage and improves rectification efficiency. This is a so-called “synchronous rectification method”, which requires a separate driving power supply and cannot be handled as two terminals.

JPA-2003348750 DC power supply circuit and standby power circuit using the power supply WO2200332105 Standby power circuit JPA_200959308 DC power switch JPA_2012506693 JPA_2013255425 System and method for imitating ideal diode of power control device JPB_6137723 Non-voltage drop type power supply circuit and its application circuit JPB_6147402 DC power distribution system JPB_6191040 Ideal diode using complex voltage drop type power supply circuit

http://www.linear-tech.co.jp/product/LTC4357 Positive high voltage ideal diode controller (LTC4357) http: // www. linear-tech. co. jp / products / Ideal_Diode_Bridge Ideal diode bridge

・ When a commercial AC power supply is electrically opened and closed using a power MOSFET or the like, a minute power of several volt to several tens of volts is required for the control circuit. The voltage is too high.
Incorporation of a general DC power supply circuit consumes much more power than is necessary to control a power MOSFET, etc., and the number of parts increases and power is consumed even when there is no load. was there. (Patent Document 3)

-DC power supply with a simple circuit configuration, such as a circuit that uses an FET to lower the voltage, may be used, but power efficiency is low, and standby power when there is no load can be completely zero There were disadvantages such as not. (Patent Documents 1 and 2)

There is also a circuit configuration called an “ideal diode” that can reduce the forward voltage of the rectifying diode using a power MOSFET or the like. (Patent Document 4, Non-Patent Documents 1 and 2)
Although an “ideal diode” is configured using a power MOSFET or the like, since it is a so-called synchronous rectification method that requires a separate power source for the control circuit, it has a circuit configuration that cannot be made into two terminals.
Even if there is a power MOSFET having a withstand voltage of several thousand volts, it cannot be used for commercial AC rectification because the withstand voltage of the control integrated circuit is insufficient.

Furthermore, DC distribution is considered to be efficient because it can reduce unnecessary AC / DC conversion, but it cannot be expected to stop spontaneously once discharge has started, so a means to stop discharge is secured. It is necessary to keep it.
As one of the methods, a method of intermittently repeating intermittently is conceivable. However, as described above, the voltage is too high to rectify commercial 100V to 220V and use it as a power source for the control circuit, and the standby power is reduced to 0. There was a drawback that could not be made.

There has been a demand for a simple method for obtaining minute DC power with a simple circuit configuration.

FIG. 1A shows a non-voltage drop type power supply (80) having a first basic circuit configuration.
A voltage dividing resistor at the source (S) of the depletion type FET (85d) (a circuit configuration using an Nch MOSFET, which can also be constituted by a Pch MOSFET or a junction type FET with reversed polarity). (89, R1, R2) and the capacitor (C1) are connected in parallel, the voltage (V1) of the AC power supply (2) is applied to the drain (D) through the diode (82) for reverse voltage protection, and the gate ( G) is connected to the midpoint of the voltage dividing resistor (89, R1, R2).

Since it is a depletion type FET (85d), even if the voltage between the gate (G) and the source (S) is 0V, the current (I1) flows between the drain (D) and the source (S). Therefore, when the voltage of the AC power supply (2) is positive, the capacitor (C1) is charged by the current (I1).
When the voltage _{divided by the} voltage _dividing resistors (89, R1, R2) is applied to the gate (G) and reaches the gate threshold voltage (V _Gth ), it is between the drain (D) and the source (S). Is cut off and charging stops.
The charging voltage (Vc _chg ) of the capacitor (C1) can be adjusted by the ratio of the voltage _dividing resistors (89, R1, R2).
Vc _chg = V _Gth x R1 / (R1 + R2)

Here, when the resistance value of the voltage dividing resistor (89, R1, R2) is set high, the capacitance (86p, Cg) is between the gate (G) and the source (S) of the depletion type FET (85d). Since it exists, it operates under the influence of its time constant τ (the product of the parallel combined resistance value of the voltage dividing resistors R1 and R2 and the capacitance (86p, Cg) between the gate (G) and the source (S)). Since a delay occurs, the capacitor (C1) is charged to a voltage higher than the charging voltage (Vc _chg ).
τ = Cg × R1 × R2 / (R1 + R2)
The next charge is not performed until the voltage (V2) of the capacitor (C1) is consumed by the load (R _L ) and the _divided voltage becomes equal to or lower than the gate threshold voltage (V _Gth ).

FIG. 1B shows an operation waveform.
Charging is performed when the voltage (V1) of the AC power supply (2) rises, and after charging to a voltage higher than the charging voltage (Vc _chg ), the voltage (V _G ) rises with a delay, and the depletion type FET The gate threshold voltage (V _Gth ) of ( _85d ) is reached and a cut-off state is entered, and charging is completed.
Since the depletion type FET (85d) conducts when the voltage (V1) of the AC power supply (2) is low, there is little power loss during charging, and if the depletion type FET (85d) continues to be cut off after charging, Furthermore, even if the power supply voltage (V1) rises, the current (I1) does not flow, so that the power consumption due to the voltage drop is small.
Although the voltage (V2) across the capacitor (C1) varies depending on the characteristics of the depletion type FET (85d) used, a direct current of several volts to several tens of volts can be obtained.

As shown in FIG. 2 (a), a condenser gate (G) and between the source _{(S) (86p, C g} ) to adjust the time constant by adding a high-resistance (Rg) in series to the gate (G) You can also (In the case where the voltage dividing resistor 89 is not divided by R1 and R2, a high resistance Rg is essential.)
The series resistance (Rf), the voltage dividing resistance (89, R1, R2), the parallel capacitance (Cs), and the like indicate elements that impede pulsed charging of the non-voltage drop type power supply (80).
The operation waveform (V2) as shown in FIG. 2B is obtained, and the charging current (I1) collapses from the pulse shape, and the current (I1) continues to flow even when the power supply voltage (V1) rises.

Depending on the setting of the time constant, excessive charging is temporarily performed as shown in the operation waveform of the voltage (V2) in FIG. 2C, and stable charging in each cycle may not be performed.
A Zener diode (82z) and a resistor (Rz) indicate a method for reducing an excessive voltage.
When a junction type FET is used as the depletion type FET (85d), the influence of the leakage current of the gate (G) must be considered.

FIG. 3A shows a complex voltage drop type power supply (80j) having a second basic circuit configuration.
This is a method of rectifying the AC power supply (2) by using a capacitor (C0) with a capacitor (C0) and securing the power for the control circuit, and is a circuit configuration method that is generally widely used.
A complex voltage drop is performed by the capacitor (C0), and the voltage is rectified by the diodes (D1, D2) to obtain DC power in the capacitors (C1, C2).
Since the complex voltage drop due to the capacitor (C0) is used, no power consumption is involved.

If the output voltage of the complex voltage drop type power supply (80j) is not consumed, the voltage (V2 +, V2-) of the capacitors (C1, C2) increases every cycle of the AC power supply (2). The voltage reaches a maximum of 1.42 times the effective voltage of the AC power supply (2).
In order to stably obtain a voltage of several volts to several tens of volts, it is necessary to make a constant voltage by consuming surplus power with a Zener diode (82z) or the like.

With a small number of parts, a minute DC power can be obtained by a simple method while avoiding a voltage drop.
Micro DC power can be obtained with high power efficiency, and many application circuits can be provided.
It is possible to provide an ideal diode that can be completely made into two terminals and an electronic switch necessary for direct current distribution.

Non-voltage drop type power supply (80) (a) Basic circuit 1, (b) Operation waveform Operation inhibiting element (a) Adjustment element, (b) Operation waveform 1, (c) Operation waveform 2 Complex voltage drop type power supply (80j) (a) Basic circuit 2, (b) Operation waveform Ideal diode (82i, non-falling type) (a) circuit configuration, (b) operation waveform, (c) symbol notation, (d) external component, (e) bridge rectifier circuit, (f) full wave rectification waveform Ideal diode (82j, complex type) (a) circuit configuration, (b) operation waveform (ideal diode), (c) operation waveform (power supply unit), (d) rectified waveform (ideal diode), (e) rectified waveform ( Power supply part) Ideal diode (82j, complex type) (a) Symbol (NchMOSFET), (b) Symbol (PchMOSFET), (c) Bridge rectifier circuit, (d) Operation waveform Duplex ideal diode (82ii) (a) Circuit configuration, (b) Parallel connection of solar cells Redundant electronic switch (84) (a) Circuit configuration, (b) Operating waveform Electronic switch that operates autonomously (84) (a) Circuit configuration, (b) Operation waveform, (c) Symbol notation Electronic switch with short circuit (84) (a) Circuit configuration, (b) Operation waveform, (c) Symbol notation Application example to DC distribution system

<Application circuit 1>
FIG. 4A shows an ideal diode (82i) using a non-voltage drop type power supply (80) which is the first basic circuit configuration.
Since the enhancement type power MOSFET (85e-1) is used as the ideal diode (82i), the conduction direction of the parasitic diode (82p) (the anode (A) to the cathode (K)) is the conduction direction of the ideal diode (82i). Configure to be
The common line (80c) of the non-voltage drop type power supply (80) is connected to the source (S) of the enhancement type power MOSFET (85e-1) to be the anode (A) of the ideal diode (82i).

The power is supplied from the non-voltage drop type power supply (80) to the operational amplifier (83), and the voltage between the source (S) and drain (D) of the enhancement type power MOSFET (85e-1) is changed to the resistance (Rs). In addition to the operational amplifier (83), a polarity detector (83D) is configured.
Only when the direction of the current (I2) is negative (the conduction direction of the ideal diode (82i)), a positive voltage (V4) is applied to the gate (G), and the gate of the enhancement type power MOSFET (85e-1) (G ) To drive the enhancement-type power MOSFET (85e-1) to reduce the voltage drop.

FIG. 4B shows operation waveforms of the circuit (a).
The upper stage shows the flow of current (I2) flowing from the drain (D) to the source (S) of the enhancement type power MOSFET (85e-1), and the lower stage shows the input voltage (V3, chain line) of the operational amplifier (83) and the operational amplifier (83). 83) (V4, solid line: voltage applied to the gate).
The current (I2) flowing through the enhancement type power MOSFET (85e-1) flows in the conduction direction of the parasitic diode (82p) (in the direction opposite to the arrow of I2), and is therefore expressed as negative.
When the voltage (V3) becomes negative, the operational amplifier (83) performs inversion amplification, and a positive voltage (V4) is applied to the gate (G).
When the direction of the current (I2) is reversed and the voltage (V3) becomes positive, the voltage (V4) of the gate (G) is quickly lowered to 0V and the enhancement type power MOSFET (85e-1) is shut off. To do.

In this example, an operational amplifier (83) that operates with a single power supply is used, but the fact that the direction of the current flowing through the on-resistance of several milliohms is reversed is detected by comparison in the negative voltage region of several millivolts. There is a need. For this reason, as shown in FIG. 4A, a high resistance (Rh) is connected to the inverting input terminal (−) of the operational amplifier 83, and a minute positive voltage is applied by the resistance voltage divider (Radj), so that the inverting input terminal The voltage of (-) is shifted to the positive voltage side.
When the voltage (V3) of the inverting input (−) of the operational amplifier (83) is positive, the output voltage (V4) goes to the ground potential, so that the internal resistance of the enhancement type power MOSFET (85e-1) increases. . As a result, the comparison input voltage further rises to provide positive feedback, so that the enhancement type power MOSFET (85e-1) goes to the cutoff state.

When the voltage (V3) is negative, if the internal resistance of the enhancement type power MOSFET (85e-1) decreases, the input voltage (V3) of the operational amplifier also decreases, so that negative feedback is provided, so the enhancement type power MOSFET The operation is performed so that the voltage between the drain (D) and the source (S) of (85e-1) maintains a constant value.
Further, since the on-resistance of the enhancement type power MOSFET (85e-1) increases when the current (I2) decreases, it is possible to obtain a condition that makes it easy to detect the direction change of the current because of the negative feedback. it can.
In order to increase the current capacity, a plurality of enhancement type power MOSFETs can be connected in parallel. Different voltage-dividing resistors are passed through the gates (G), for example, so that the voltages to be turned on are different, the loop gain is lowered, and the current direction change can be easily detected. (Suppresses excessive gain by adding FET.)

The ideal diode (82i) using the non-voltage drop type power supply (80) can handle the entire circuit as a two-terminal ideal diode (82i).
FIG. 4C is a symbolized representation of an ideal diode (82i) using a non-voltage drop type power supply (80).
An arrow extending from the cathode (K) (in the case of an Nch MOSFET) is a symbol of an ideal diode (82i) indicating that power is supplied to the internal circuit.

FIG. 4D is also a representation of the ideal diode 82i symbolized, but clearly shows that the capacitor C1 of the non-voltage drop type power supply 80 is externally attached. (There is no change that it can be handled as two terminals.)
FIG. 4 (e) represents a bridge rectifier circuit (24) constituted by an ideal diode (82i) using the symbols shown in FIG. 4 (d).
Since the diodes (Dc) and (Dd) connect the anodes (A), both the common lines (80c) have the same potential. Therefore, the non-voltage drop type power supply (80) can be shared with each other. it can. (Effective when configuring a module.)

In the diodes (Da) and (Db), since the arrow line for supplying power is on the cathode (K) side, the common line (80c) is not at the same potential, and the built-in non-voltage drop type power supply circuit (80) is provided. It cannot be shared.
When an ideal diode (82i, including a non-voltage drop type power supply (80)) is configured using an enhancement type power MOSFET of Pch, since the cathodes become a common line (80c), the diode (Da) It is possible to share the non-voltage drop type power supply (80) of (Db) with each other.
In this case, the operational amplifier (83) to be used is an operational amplifier that can operate with a single power source that operates normally even when the common-mode input voltage of the input terminals (+,-) becomes a voltage near the positive power supply voltage. It is necessary to use it.

When the ideal diodes (82i) configured using Nch and Pch enhancement type power MOSFETs (85e-1) are respectively diodes (Da, Dc), the terminals connected to the AC power supply 2 are connected to the common line (80c). Therefore, since both a positive power source and a negative power source can be used in the internal circuit, the dual power source can be used for the operational amplifier (83). (The same applies to the combination of the diodes Db and Dd.)
We have explained the symbol that the capacitor (C1) is externally attached. However, if the current consumption of the operational amplifier used is small, the capacity of the capacitor (C1) can be reduced. Is also possible.

In the rectifier circuit for obtaining direct current, the voltage of the smoothing capacitor (C2) is applied, so that the conduction angle of the current flowing in the forward direction is reduced, but the reverse voltage is applied to the ideal diode (82i) at the non-conduction angle. Therefore, power for driving the circuit can be obtained by the non-voltage drop type power supply (80).
The ideal diode (82i) of the application circuit 1 is limited to a use such as a rectifier circuit to which a reverse voltage is repeatedly applied.

<Application circuit 2>
FIG. 5A shows an ideal diode (82j) configured using a complex voltage drop type power supply (80j) and an Nch enhancement type power MOSFET (85e-1), which are the second basic circuit configuration.
The common line (80c) of the complex voltage drop type power supply (80j) is connected to the source (S) of the enhancement type power MOSFET (85e-1) to become the anode (A) of the ideal diode (82i) and the drain (D) Becomes the cathode (K).

Power is supplied from the complex voltage drop type power supply (80j) to the operational amplifier (83), and the voltage between the drain (D) and the source (S) of the enhancement type power MOSFET (85e-1) is changed to the resistance (Rs). In addition to the inverting input (−) and the non-inverting input (+) of the operational amplifier (83), a polarity detector (83D) is configured.
The diode (82, D3) is for protecting an overvoltage of the operational amplifier (83).

FIG. 5B shows the waveform of the rectification operation of the ideal diode (82j). The upper stage shows the flow of the current (I2) flowing from the drain (D) to the source (S) of the enhancement type power MOSFET (85e-1), and the lower stage shows the voltage (V3) of the inverting input terminal (−) of the operational amplifier (83). (Chain line) and the output voltage of the operational amplifier (83) (V4: solid line, also applied to the gate G).
Since the actual current (I2) flows in the conduction direction of the parasitic diode (82p), it is expressed as negative.

As shown in FIG. 5C, when the voltage (V3) of the inverting input terminal (−) of the operational amplifier (83) becomes negative (the direction of the current (I2) is the conduction direction of the parasitic diode (82p). ) Is inverted and amplified by the operational amplifier (83), and a positive voltage (V4) is applied to the gate (G) to make the enhancement type power MOSFET (85e-1) conductive.
When the direction of the current (I2) is reversed and the voltage (V3) becomes positive, the voltage (V4) applied to the gate (G) is quickly lowered to 0 V or less to cut off the power MOSFET (85e-1).
When the load (R _L ) is a pure resistance, as shown in FIG. 5C, only the positive half cycle of the AC power source (2) is applied to the capacitor (C0), and during this time, the capacitor (C0) is reciprocated in both directions. A current (I1) flows through.
During the positive half cycle of the AC power supply (2), the capacitors (C1, C2) are charged in sequence.

When a smoothing capacitor (C3) is added to the load of the ideal diode (82j), the conduction angle of the ideal diode (82j) becomes narrow as shown in FIG. With reference to the potential (V0) of the line (80c), the voltage (V1) applied to the ideal diode (82j) is, as shown in FIG. The voltage waveform is shifted in the positive direction.

The current (I1) flowing through the capacitor (C0) is proportional to the voltage of the AC power supply (2).
Therefore, since the ideal diode (82j) optimized for AC 1000V may be insufficient for driving when used at AC 100V, it is necessary to design the ideal diode (82j) for each range of operating voltage. is there.
In addition, the current (I1) flowing through the capacitor (C0) varies depending on the rectification method and the frequency (50 Hz, 60 Hz, etc.) of the AC power supply (2), so it is necessary to design for the application.

In the circuit of FIG. 5A, when connected to a power supply of AC 100V, 60 Hz and the capacitor (C0) is 0.1 μF, the operational amplifier (83) with a current consumption of about 0.5 mA can be driven.
When the operational amplifier (83) having a current consumption of about 0.1 mA is used, the capacitor (C0) can be reduced to 0.02 μF.

Since both positive and negative power supplies can be used, it is not necessary to limit the specifications of the operational amplifier (83) to be used.
Since the direction of the current (I2) flowing through the on-resistance of the enhancement type power MOSFET (85e-1) can be directly compared in the negative voltage region, the resistance component is connected to the positive input terminal (+) of the operational amplifier (83). A negative voltage of several millivolts is applied by a pressure device (Radj).

When the voltage (V3) of the inverting input terminal (−) of the operational amplifier (83) is negative, the voltage (V3) of the gate (G) decreases when the internal resistance of the enhancement type power MOSFET (85e-1) decreases. Therefore, since negative feedback occurs, the operation is performed so that the voltage between the drain (D) and the source (S) of the enhancement type power MOSFET (85e-1) maintains a constant value.
In addition, since the negative feedback is provided, the on-resistance of the enhancement type power MOSFET (85e-1) increases when the current (I2) decreases, but it is possible to obtain a condition for easily detecting the direction change of the current. it can.
The loop gain is adjusted to set the operating range of the ideal diode (82j) according to the application.

When the voltage (V3) of the inverting input terminal (−) of the operational amplifier (83) is positive, the inverting output (V4) is directed to the potential below the common line (80c), so that the enhancement type power MOSFET (85e-1 ) Goes to the shut-off state.
When the Pch enhancement type power MOSFET (85e-1) is used, the conduction direction is reversed, so that the display of the anode (A) and the cathode (K) in FIG. It is necessary to connect (Radj) to the positive voltage side and apply a positive voltage of several millivolts to the non-inverting input terminal (+).
The ideal diode (82j) using the complex voltage drop type power supply (80j) can handle the entire circuit as a two-terminal ideal diode (82j).

FIG. 6A is a symbolic representation of an ideal diode (82j) using an Nch enhancement type power MOSFET (85e-1) and a complex voltage drop type power supply (80j).
The symbol is an arrow with a capacitor symbol extending from the cathode (K), indicating that power is being supplied to the internal circuit.

FIG. 6B is a symbolized representation of an ideal diode (82j) using a Pch enhancement type power MOSFET (85e-1).
Compared with Nch, the anode (A) and the cathode (K) are interchanged, and the arrow changes to an arrow extending from the anode (A).
FIG. 6C shows the bridge rectifier circuit 24 using the symbols in FIG. 6A, and FIG. 6D shows its operation waveform.
Since the voltage of the smoothing capacitor (C3) is applied, the conduction angle of the forward current (I2) is reduced.
At the non-conduction angle, a reverse voltage is applied to each ideal diode (82j), so that power for driving the circuit can be obtained from the complex voltage drop type power supply (80j).

The ideal diode (82j) is limited to applications where a voltage in the reverse direction is repeatedly applied, such as a rectifier circuit of the AC power supply (2).
The breakdown voltage and capacity of the capacitor (C0) are selected according to the voltage range applied in the reverse direction.
In the figure, an example using a complex voltage drop type power supply (80j) having both positive and negative power supply configurations is shown. However, a capacitor (C1) and a Zener diode (Dz1) or a capacitor (C2) and a Zener diode (Dz2) are shown. By omitting any one of () and making a short circuit, a complex voltage drop type power supply circuit (80j) of a single power source of only positive or only negative can be configured.

Although the number of parts can be reduced slightly, in the case of a single power supply, the non-inverting input (+) of the operational amplifier (83) is connected to the common line (80c), and a resistor is connected to the inverting input (−). It is necessary to apply a voltage of several millivolts.
By replacing all or part of the Zener diode (82z) that consumes surplus power with LEDs, it can be used as a light source such as an indication of the operating state or a power indicator of a device incorporating the ideal diode (82j). .

<Application circuit 3>
FIG. 7A shows an ideal diode (82ii) configured by using a non-voltage drop type power supply (80) which is a first basic circuit and two enhancement type power MOSFETs (85e-1).
In the application circuit 1, in the backflow prevention diode used for connecting the solar cells of a plurality of systems in parallel, a forward current always flows, and thus driving power cannot be obtained.
The ideal diode (82ii) in FIG. 7A has a configuration in which the enhancement type power MOSFET (85e-1) is temporarily cut off and driving power is obtained from the voltage non-drop-type power supply (80).

Two enhancement type power MOSFETs (85e-1, 85e-2) can be used, and can withstand even when a voltage is applied in the reverse direction. After obtaining power, a voltage is applied to the gate (G) to make the two enhancement type power MOSFETs (85e-1, 85e-2) conductive.
The polarity of the differential input terminal of the operational amplifier (83) is opposite to that of the application circuit 1, and the two enhancement type power MOSFETs (85e-1, 85e-2) are simultaneously turned on according to the direction of the current. Since the interruption is performed, the direction of the current (I2) is the forward direction of the ideal diode (82ii).

When the voltage (V2) of the non-voltage drop type power supply (80) drops to the gate threshold voltage (V _Gth-3 ) of the MOSFET (85e-3), the MOSFET (85e-3) is cut off and the operational amplifier (83) Since the inverting input (−) becomes 0 V, the output is inverted to cut off the two enhancement type power MOSFETs (85e-1, 85e-2).
Although not shown in the figure, the voltage to be inverted can be adjusted by adding a voltage dividing resistor (89) to the gate (G) of the MOSFET (85e-3).

Due to the time constant τ between the high resistance (88, Rg) connected to the gate (G) of the MOSFET (85e-3) and the capacitance (86p, Cg) between the gate (G) and the source (S). Since an operation delay occurs, the capacitor (C1) can be charged excessively. (Since it competes with the time constant τ of the non-voltage drop type power supply (80), set it to the same level.)
The voltage between the drain (D) and the source (S) of the enhancement type power MOSFET (85e-1) rises at the time of interruption, but since it is cut off by the MOSFET (85e-3), the operational amplifier (83) is not affected. It doesn't reach.

In the case of the application circuit 3, it is possible to design by omitting the depletion type FET (85d) and the voltage dividing resistors (89, R1, R2) of the non-voltage drop type power supply (80).
In this case, the cathode (K) of the diode (82) and the capacitor (C1, + terminal) are directly connected.
However, it can be used as a switch to disconnect the solar cell system by disconnecting the switch (87, SW) in the figure, but it must be assumed that all voltages of the system are applied. The FET (85d) or the like cannot be omitted. (It can be omitted by changing the insertion point of the switch (87, SW).)

FIG. 7 (b) shows the solar diode panel (11) connected in parallel using the symbol of the ideal diode (82ii) (the bar structure of the diode symbol is outlined because the internal configuration is different). A connection example is shown.
When solar panels (11) of a plurality of systems are connected in parallel and the power conditioner (13) is operating at the optimum input voltage, a voltage increase of about 5% when one system is shut down (system When the voltage is 400 V, about 20 V) is expected, and driving power can be obtained by performing a short interruption of about several tens of milliseconds for each system.
In the case of a circuit configuration using two enhancement type power MOSFETs (85e-1, 85e-2), the common line (80c) cannot be shared with an external circuit.

<Application circuit 4>
FIG. 8A shows a first basic circuit configuration, a non-voltage drop type power supply (80) and two enhancement type power MOSFETs (85e-1 and 85e-2), which are turned on and off according to illuminance. An electronic switch (84) used for the AC commercial power supply (2).
FIG. 8B shows an operation waveform. (The broken line is an operation waveform when the illuminance is large.)

When the voltage of the AC power supply (2) is positive, the voltage of the non-voltage drop type power supply (80) is not exceeded by the diode (82-2) through the diode (82-1) and the resistor (88, Rs). Restricted to Further, the voltage (V3) is applied to the non-inverting input terminal (+) of the operational amplifier (83) through the voltage dividing resistors (89, R3, R4).
A voltage (V2) divided by the optical sensor (84s, CDS) and the resistor (88, Rh) is applied to the inverting input terminal (−) of the operational amplifier (83). When the illuminance is high, the resistance value of the optical sensor (84s, CDS) decreases, and the voltage (V2) of the inverting input terminal (−) increases.
The voltage divider resistors (89, R3, R4) are set so that the voltage at the non-inverting input terminal (+) does not exceed the voltage (V2) at the inverting input terminal (−) when the illuminance is high. Therefore, the output terminal of the operational amplifier (83) is 0 volts.

When the illuminance decreases and the voltage (V2) of the inverting input terminal (−) decreases, the voltage (V3) of the non-inverting input terminal (+) increases, so that the operational amplifier (83 ) Rises to drive the one-shot pulse generator (84p).
The one-shot pulse generator (84p) drives the gates (G) of the two enhancement type power MOSFETs (85e-1 and 85e-2) and conducts them for a certain time (t).

As shown in the operation waveform of FIG. 8B, the electronic switch (84) in the operating state cuts off the current (I2) and charges the non-voltage drop type power supply (80).
The output pulse width (t) of the one-shot pulse generator (84p) is set slightly shorter than the cycle (T) of the AC power supply (2) so as not to hinder the charging of the non-voltage drop type power supply (80). .
In order to provide positive feedback to the non-inverting input terminal (+) of the operational amplifier (83) by the diode (82-3), the capacitor (C3) and the resistor (88, Rf), and to ensure the on-off transition, Has hysteresis.

<Application circuit 5>
FIG. 9A shows an electronic switch (84) composed of a first non-voltage drop type power supply (80) and an enhancement type power MOSFET (85e-1) as the first basic circuit configuration.
In order to distribute DC power safely, it is required that the discharge generated in the distribution section can be extinguished reliably.
The periodic pulse generator (84P) is built in, and the enhancement type power MOSFET (85e-1) is repeatedly turned on and off, and at the moment of interruption, the current (I1) flows to the non-voltage drop type power supply (80) to drive Power is obtained in the capacitor (C1).
When there is no load, the non-voltage drop type power supply (80) is completely stopped, so that useless power is not consumed.

FIG. 9B shows operation waveforms.
The voltage (V1) is the voltage of the power supply (1), the voltage (V4) is the voltage between the gate (G) and the source (S), and the current (I1) is the charge of the non-voltage drop type power supply (80). Current is shown.
When the power source (1) and the load (R _L ) are connected, a current (I1) flows, and driving power is obtained in the capacitor (C1).
Next, the periodic pulse generator (84P) conducts the enhancement type power MOSFET (85e-1) for a certain period of time, and supplies power to the load (R _L ).
When the enhancement type power MOSFET (85e-1) is cut off, the current (I1) flows, and driving power is obtained in the capacitor (C1), and this is repeated.
Since an intermittent direct current is output to the output terminal (80O) of FIG. 9A, the output of the application circuit 5 is a power supply (12) whose voltage changes.

FIG. 9C is a symbolized representation of the electronic switch (84) driven by the periodic pulse generator (84P).
When the periodic pulse generator (80P) is not built in, it is necessary to connect and use the power supply (12) whose voltage changes.
When the voltage of the output terminal (80O) does not decrease, such as a capacitive load, driving power may not be obtained.
Due to the influence of the parasitic diode (82p), the direction of the voltage applied to the electronic switch (84) is limited.

<Application circuit 6>
FIG. 10A shows a first non-voltage drop type power supply (80) and an N-ch enhancement type power MOSFET (85e-1), a P-ch MOSFET (85x), and a first basic circuit configuration. Equipped with an overcurrent detector (84I) and safety electrode current detector (84g) that operate with power from a non-voltage drop type power supply (80), or other sensors (earthquake, fire) not shown in the figure This is an electronic switch (84) that can be operated in various ways according to the above signal.

FIG. 10B shows an operation waveform.
The voltage (V1) is the voltage of the power supply (1), the voltage (V4) is the voltage between the gate (G) and the source (S), and the current (I1) is the charge of the non-voltage drop type power supply (80). The current (I3) indicates the current of the Pch MOSFET (85x).
When the power source (1) and the load (R _L ) are connected, a current (I1) flows, and driving power is obtained in the capacitor (C1).
The enhancement type power MOSFET (85e-1) is turned on for a certain period of time to supply power to the load.
When the enhancement type power MOSFET (85e-1) is cut off, if the load (R _L ) is capacitive, the voltage across the load is maintained, so there is a possibility that sufficient current (I1) does not flow. is there.

Therefore, immediately after the enhancement type power MOSFET (85e-1) is cut off, the Pch MOSFET (85x) is pulse-driven to short-circuit the load (R _L ) to obtain currents (I1, I3) for driving. It is the structure which ensures the electric power of.
Since driving of the Pch MOSFET (85x) requires a negative voltage, a negative pulse voltage is applied to the gate (G) by capacitive coupling (Cc, R4).
At the same time, a reverse voltage is applied to the ideal diodes (82i, 82j, 82ii) used on the load side by using the voltage accumulated in the capacitor (C6) to secure driving power. (Although not shown in the figure, when the enhancement type power MOSFET (85e-2) is provided, the enhancement type power MOSFET (85e-2) is turned on simultaneously with the Pch MOSFET (85x).)

Even if it is a capacitive load (R _L ), the current (I1) can be obtained with certainty, but even when there is no load, it is not shown in the figure because it continues to operate with power for driving. However, it is desirable to monitor the supply current (I2) to the load (R _L ) and stop the operation when there is no load.
In order to reliably detect a small current, the on-resistance was increased by forming a negative feedback path and controlling the voltage drop of the enhancement type power MOSFET (85e-1) to be a constant value around 10 millivolts. Even in the situation, if the voltage drop is several millivolts or less, it can be reliably detected that there is no load.

FIG. 10C represents a safety breaker (31) for direct current distribution that interrupts power using the symbol of the electronic switch (84).

<Application circuit 7>
FIG. 11 shows a “DC power distribution system” that intermittently supplies power using an electronic switch (84) including a non-voltage drop type power supply (80) that is a first basic circuit configuration.
The DC power distribution system supplies intermittent power at different times from the power distribution board (3) through two lines of wiring, and combines them with ideal diodes (82i, 82j, 82ii) on the electrical equipment (6) side. It has a configuration that can receive no DC power. (In the case of the low-power electric device (6), it is operated by supplying one system. Similar to the single-phase three-wire wiring of the commercial AC power supply, it is applied to the high-power electric device (6). Reference 6)

In order to alternately interrupt the two systems, they must be synchronized with each other.
As shown in FIG. 11, when an electronic switch (84, Sa, Sb) using an Nch enhancement type power MOSFET is arranged on the positive electrode side of the DC power supply (1) to try to interrupt the circuit, two electronic switches Since the common line (80c, not shown in the drawing) of (84, Sa, Sb) is not common, a circuit for synchronization cannot be directly connected.

Although not shown in the figure, when a Pch enhancement type power MOSFET is used, the positive side of the DC power supply becomes a common line (except when 80c and two power MOSFETs are used). Can be easily connected.
As shown in FIG. 11, if a photocoupler (84c) or the like is used, it is possible to easily connect between circuits having different potentials. Therefore, in addition to opening / closing of the electronic switches (84, Sa, Sb), As shown in FIG. 11, the commercial AC power source (2) and the periodic pulse generator (84P) can be easily synchronized.

In order to introduce a DC power distribution system in an environment where a commercial AC power source (2) that is widely used is dominant, it is essential to ensure compatibility.
The electric device (6) that operates with the intermittent direct current (12) can be designed to operate with the non-smooth direct current (12) obtained by full-wave rectification of the commercial AC power supply (2).
Using a conversion plug and conversion outlet with a built-in bridge rectifier (24) of ideal diodes (82i, 82j, 82ii), electrical equipment (6) operating on DC can be connected to commercial AC power supply (2) is there.

When an electronic switch or the like is used for a commercial power supply, a minute DC power supply for driving is necessary.
The present application can provide a practical ideal diode or electronic switch by efficiently and easily obtaining a minute DC power, and driving a power MOSFET or the like using the power to provide a practical ideal diode or electronic switch. A rectifier circuit, a DC power distribution system, or the like can be configured.

1 DC power supply 11 Solar cell 12 Half-wave / double-wave rectification (non-smooth), intermittent DC
(Converter) 13 Power conditioner (DC / AC converter)
2 AC power supply
(Rectifier) 24 double-wave rectifier (bridge rectifier)
3 Wiring board 30 Main breaker 31 Safety breaker 3f Filter 4 Outlet 5 Plug 6 Electrical equipment 69 Internal circuit 8 Parts 80 Non-voltage drop type power supply 80j Complex voltage drop type power supply 80c Common line 80o Power supply output terminal 80O Output terminal (Output of application circuit) Terminal)
81 Power input terminal 82 Diode (D1, D2) 82p Parasitic diode
82i, 82j, 82ii Ideal diode (Da to Dd)
82b Bridge rectifier 82z Zener diode (Dz1, Dz2)
83 operational amplifier (for single power supply) 83D polarity detector
84 Electronic switch (S, Sp, Sa, Sb, Spa-Spb)
84c Photocoupler 84d FET driver
84g Safety electrode current detector 84I Overcurrent detector 84P Periodic pulse generator 84p One shot pulse generator 84s Various sensors (human sensor, illuminance sensor, etc.)
85d Depletion type FET (Nch)
85e 85e-1 to 3 enhancement type power MOSFET (Nch)
85x enhancement type MOSFET (Pch)
86 Capacitors (C0, C0a to C0d, C1, C1a to C1d, C2, C3, C4, C6, Cc, Ci)
86p Capacitance (Cg, C _G )
87 Switch (SW)
88 resistors (Rf, Rg, R _h , R _L , Rs, Rz)
89 _Voltage divider resistors (R1, R2, R3, R4, R _adj )
9 Others 90 Grounding (ground) 91 Case I Current (I1, I2)
V voltage (V1 to V4, V0: voltage reference, common line 80c)

Claims (7)

A depletion type FET (85d, Nch and Pch MOS type and junction type field effect transistors; the same applies hereinafter), a capacitor (86, C1), and a diode (82),
The drain (D) of the depletion type FET (85d) is connected to the power input terminal (81) through the diode (82).
The gate (G) is connected to the voltage dividing resistor (89, R1, R2) through the resistor (88) or directly.
A source (S) is connected to one of the voltage dividing resistors (89, R1), the capacitor (86, C1) and the output terminal (80o).
Connecting the capacitor (86, C1, other terminal) and the other one of the voltage dividing resistors (89, R2) to a common line (80c), respectively;
Configure a circuit that outputs the common line (80c) and the output terminal (80o),
When the voltage of the power input terminal (81) becomes a voltage around the required voltage,
Capacitance (86p, Cg, C _G ) between the gate (G) and the source (S) of the depletion type FET (85d) and a resistor (the resistor 88 and the voltage dividing resistor) in series with the gate (G) Due to the operation delay due to the time constant τ with respect to the combined resistance value of the capacitor 89, through the depletion type FET (85d), the voltage dividing ratio of the voltage dividing resistor (89, R1, R2) to the capacitor (86, C1) A non-voltage drop type power supply (80) characterized in that a DC power is obtained by avoiding a voltage drop accompanied by power loss by charging to a voltage higher than a determined voltage.
Non-voltage drop type power supply (80) and enhancement type power MOSFET (85e, Nch and Pch MOS field effect transistors, including a plurality of FETs of the same type connected in parallel to increase current capacity, and so on. )
The drain (D) is connected to the non-voltage drop type power supply (80) and the power supply input terminal (81).
The source (S) is connected to the common line (80c) and the output terminal (80O), respectively.
An electronic switch (84) controlled by applying a voltage between the source (S) and the gate (G) of the enhancement type power MOSFET (85e-1) by the electric power obtained from the non-voltage drop type power source (80). The application circuit of the non-voltage drop type power supply (80) according to claim 1, wherein
Non-voltage drop type power supply (80) and enhancement type power MOSFET (85e, Nch and Pch MOS field effect transistors, including a plurality of FETs of the same type connected in parallel to increase current capacity, and so on. ) 2 (2 sets if a plurality of FETs are connected in parallel),
The source (S) and gate (G) of the two (two sets) enhancement type power MOSFETs (85e-1, 85e-2) are connected and connected in series,
On the other hand, the drain (D) of (85e-1) is connected to the non-voltage drop type power supply (80) and the power input terminal (81).
Connect the drain (D) of the other (85e-2) to the output terminal (80O) and the sources (S) of both (85e-1, 85e-2) to the common line (80c),
Control is performed by applying a voltage between the source (S) and the gate (G) of the enhancement type power MOSFETs (85e-1, 85e-2) by the electric power obtained from the non-voltage drop type power supply (80). The application circuit of the non-voltage drop power supply (80) according to claim 1, characterized in that it constitutes an electronic switch (84) capable of dealing with bidirectional voltages.
Non-voltage drop type power supply (80) and enhancement type power MOSFET (85e, Nch and Pch MOS type field effect transistors. Including those connected in parallel and those connected in series, and the same). Prepared,
An environment in which an unnecessarily high voltage is not applied to the non-voltage drop type power supply (80) (the applied voltage is lower than the withstand voltage of the components of the internal circuit, or after storing the necessary voltage power, the voltage non-drop In an environment where the enhancement type power MOSFETs (85e-1, 85e-2) connected in parallel with the type power supply (80) are made conductive and an excessive voltage is not applied). The depletion type FET (85d) constituting the non-voltage drop type power supply (80) is omitted (the depletion type removed by removing the resistor (88) and the voltage dividing resistor (89) connected to the gate (G)). The wiring to the drain (D) and the source (S) of the FET (85d) is directly connected.)
The application circuit of the non-voltage drop type power supply (80) according to any one of claims 1 to 3.
Non-voltage drop type power supply (80), enhancement type power MOSFET (85e, Nch and Pch MOS field effect transistors. Including those in which FETs of the same type are connected in parallel and in series, and both. The same shall apply hereinafter), and an enhancement type MOSFET (85x, Pch and Nch MOS field effect transistors, which are different from the enhancement type power MOSFET (85e-1)).
The non-voltage drop type power supply (80) and the enhancement type power MOSFET (85e-1) are connected in parallel, and connected in series between the power supply and a load (R _L ), and
The enhancement type MOSFET (85x) is connected in parallel to the load (R _L ),
Shuts off the enhancement type power MOSFETs (85e, 85e-1);
By conducting between the drain (D) and the source (S) of the enhancement type MOSFET (85x), power is obtained from the non-voltage drop type power supply (80) regardless of the load (R _L ). And
The application circuit of the non-voltage drop type power supply (80) according to any one of claims 1 to 4.
Non-voltage drop type power supply (80) and enhancement type power MOSFET (including those in which 85e, Nch and Pch MOS field effect transistors are connected in parallel and connected in series, and both are applied. The same applies hereinafter) and ,
A current direction detector (including those composed of 83D, operational amplifier 83, etc., the same shall apply hereinafter)
When voltage is applied to the non-voltage drop type power source (80) connected in series between the power source and the load (R _L ), the power of the voltage necessary for driving is accumulated,
The direction of current is detected by the current direction detector (83D), and the conduction direction of the parasitic diode (82p) of the enhancement type power MOSFET (85e-1, 85e-2) connected to the output terminal (80O) is detected. Only when a current flows, a voltage is applied between the source (S) and the gate (G) to make the drain (D) and the source (S) conductive.
An ideal diode (82i, 82ii) that can be handled as two terminals is configured.
The application circuit of the non-voltage drop type power supply (80) according to any one of claims 1 to 4.
A capacitor (C0, C1, C2), a diode (D1, D2), and a Zener diode (Dz1, Dz2);
The midpoint of the diodes (D1, D2) connected in series is connected to the power input terminal (81) via the capacitor (C0), and one end is connected to the other end of the diode (D1, D2) with a common line ( 80c) is connected to the capacitors (C1, C2) and the Zener diodes (82z, Dz1, Dz2), and outputs a positive and negative DC power, a dual power supply type complex voltage drop power supply circuit (80j), and
Either the capacitor (C1) and the zener diode (82z, Dz1) or the capacitor (C2) and the zener diode (82z, Dz2) of the complex voltage drop type power supply circuit (80j) is omitted, and the common line (80c) And a single power supply type complex voltage drop type power supply circuit (80j) that outputs positive-only or negative-only DC power,
A polarity detector (83D) configured using any of the complex voltage drop type power supply circuit (80j), the operational amplifier (83), and the like, and an enhancement type power MOSFET (85e: Nch and Pch MOSFETs, the same type). Including MOSFETs connected in parallel. The same shall apply hereinafter.)
The drain (D) and source (S) of the enhancement type power MOSFET (85e-1) are connected to the power input (81) and the common line (80c), respectively.
The voltage between the drain (D) and the source (S) is applied to the inverting input (−) of the operational amplifier (83) constituting the polarity detector (83D) through a circuit (Rs, D3, Radj) such as overvoltage protection. And non-inverting input (+) respectively,
The direction of the current (voltage) flowing through the enhancement type power MOSFET (85e-1) is detected by the polarity detector (83D), and the voltage applied to the gate (G) is controlled to control the conduction direction of the parasitic diode (82p). An ideal diode (82j) that can be treated as a two-terminal device that conducts a drain (D) and a source (S) by applying a voltage between the source (S) and the gate (G) only when a current flows through ).

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