A drive control circuit and an auxiliary power supply

Abstract

The utility model discloses a drive control circuit and auxiliary power supply, wherein including voltage comparison circuit and switching circuit, voltage comparison circuit exports the pilot signal when the voltage of power supply end of its power supply chip is no less than the preset drive voltage of drive switch tube, to make switching circuit make the circuit between the drive signal output end of power supply chip and the control end of drive switch tube conduct, and then make the drive signal of power supply chip output to drive switch tube control. Visible, the circuit between the drive signal output end of power supply chip and the control end of drive switch tube only conducts when the voltage of power supply end of power supply chip is no less than the preset drive voltage of drive switch tube, thereby guaranteeing that the voltage of drive signal of power supply chip to drive switch tube control is enough big, avoids drive switch tube and overheats damage because the voltage of drive signal is small and can not completely conduct.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a drive control circuit and an auxiliary power supply. Background Technology

[0002] A photovoltaic (PV) inverter converts the direct current (DC) generated by photovoltaic (PV) solar panels into alternating current (AC) for grid connection or to power AC loads. The output of the PV string is connected to the DC input terminal of the inverter. Therefore, the DC power output from the PV string is collected on the DC bus of the inverter and then transmitted to the inverter bridge. The inverter inverts the DC bus voltage to output AC power. Typically, the magnitude of the DC power output from the PV modules changes due to variations in sunlight intensity, causing fluctuations in the DC bus voltage.

[0003] During operation, photovoltaic inverters require a stable power supply for their internal low-power circuits that perform control, monitoring, and protection functions. Therefore, current technology draws power from the inverter's DC bus and uses a power chip to control the drive switching transistors, converting the DC bus voltage into pulsed DC current to power the corresponding equipment. Since the power chip's operating power also comes from the DC bus voltage, its operating voltage fluctuates with changes in the DC bus voltage. Because the power chip has a wide operating voltage range, small fluctuations in the DC bus voltage do not affect its normal operation. However, the voltage of the drive signal used by the power chip to control the drive switching transistors is affected by the chip's operating voltage. If the drive signal voltage is lower than the stable operating voltage of the drive switching transistors, the transistors may not fully conduct, resulting in higher on-resistance and potentially causing overheating and damage. Utility Model Content

[0004] The purpose of this invention is to provide a drive control circuit and an auxiliary power supply. The circuit between the drive signal output terminal of the power chip and the control terminal of the drive switch transistor is only turned on when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switch transistor. This ensures that the voltage of the drive signal used by the power chip to control the drive switch transistor is large enough, and avoids the drive switch transistor from overheating and being damaged because it cannot be fully turned on due to a low voltage of the drive signal.

[0005] To solve the above-mentioned technical problems, this utility model provides a drive control circuit, including a voltage comparison circuit and a switching circuit;

[0006] The input terminal of the voltage comparison circuit is connected to the power supply terminal of the power chip, and is used to output a turn-on signal when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switching transistor.

[0007] The first terminal of the switching circuit is connected to the drive signal output terminal of the power chip, and the second terminal is connected to the control terminal of the drive switching transistor. The control terminal is connected to the output terminal of the voltage comparison circuit. When the conduction signal is received, the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor is turned on, so that the power chip outputs a drive signal to control the drive switching transistor.

[0008] Preferably, the voltage comparison circuit includes a first voltage divider resistor, a second voltage divider resistor, a pull-up resistor, and a voltage comparison unit;

[0009] The first end of the first voltage divider resistor and the first end of the pull-up resistor are connected, and are also connected to the power supply terminal of the power chip.

[0010] The second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor, and the second end of the second voltage divider resistor is grounded;

[0011] The control terminal of the voltage comparison unit is connected to the second terminal of the first voltage divider resistor, the first terminal of the voltage comparison unit is connected to the second terminal of the pull-up resistor, the second terminal of the voltage comparison unit is grounded, and the first terminal of the voltage comparison unit is connected to the control terminal of the switching circuit.

[0012] The voltage comparison unit is used to conduct the circuit between its first and second terminals when the voltage at its control terminal is not less than the preset conduction voltage, so as to output the conduction signal to the control terminal of the switching circuit.

[0013] The preset on-state voltage is the voltage across the second voltage divider resistor when the voltage at the power supply terminal of the power chip is the preset drive voltage.

[0014] Preferably, the voltage comparison unit is a TL431.

[0015] Preferably, the voltage comparison circuit further includes a filter capacitor, the first end of which is connected to the first end of the second voltage divider resistor, and the second end of which is connected to the second end of the second voltage divider resistor.

[0016] Preferably, the switching circuit includes a control switch transistor, the first end of which is connected to the drive signal output terminal of the power chip, the second end of which is connected to the control terminal of the drive switch transistor, and the control terminal is connected to the output terminal of the voltage comparison circuit, for conducting when the conduction signal is received.

[0017] Preferably, the conduction signal is a low level;

[0018] The control switch is a PNP transistor.

[0019] Preferably, it further includes a current-limiting resistor, the first end of which is connected to the drive signal output terminal of the power chip, and the second end of which is connected to the first end of the control switch transistor.

[0020] To solve the above-mentioned technical problems, this utility model provides an auxiliary power supply, including the drive control circuit as described above, as well as a power chip and a drive switching transistor.

[0021] Preferably, it also includes a transformer, a charging capacitor, a charging resistor, and a reverse protection diode;

[0022] The first end of the charging resistor is connected to the first end of the DC bus capacitor, the second end of the charging resistor is connected to the first end of the charging capacitor, the first end of the charging capacitor is connected to the power supply terminal of the power chip, the first end of the charging capacitor is connected to the cathode of the anti-reverse diode, the anode of the anti-reverse diode is connected to the first end of the secondary coil of the transformer, the second end of the secondary coil of the transformer is connected to the second end of the charging capacitor and grounded, the first end of the primary coil of the transformer is connected to the first end of the DC bus capacitor, the second end of the primary coil of the transformer is connected to the first end of the drive switch transistor, the second end of the drive switch transistor is grounded, and the second end of the DC bus capacitor is grounded.

[0023] Preferably, it also includes a compensation voltage supply circuit;

[0024] The output terminal of the compensation voltage providing circuit is connected to the compensation terminal of the power chip, and is used to provide a compensation voltage to the power chip so that the power chip outputs a drive signal based on the compensation voltage.

[0025] This application provides a drive control circuit and an auxiliary power supply, including a voltage comparison circuit and a switching circuit. The voltage comparison circuit outputs a conduction signal when the voltage at the power supply terminal of its power chip is not less than a preset drive voltage of the drive switching transistor. This causes the switching circuit to connect the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor, thereby enabling the power chip to output a drive signal to control the drive switching transistor. Therefore, the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor only conducts when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switching transistor. This ensures that the voltage of the drive signal used by the power chip to control the drive switching transistor is sufficiently large, preventing the drive switching transistor from overheating and being damaged due to insufficient drive signal voltage preventing complete conduction. Attached Figure Description

[0026] To more clearly illustrate the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of a drive control circuit provided in this application;

[0028] Figure 2 A specific structural schematic diagram of a drive control circuit provided in this application;

[0029] Figure 3 This is a partial structural diagram of an auxiliary power supply provided in this application. Detailed Implementation

[0030] The core of this utility model is to provide a drive control circuit and an auxiliary power supply. The circuit between the drive signal output terminal of the power chip and the control terminal of the drive switch tube is only turned on when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switch tube. This ensures that the voltage of the drive signal used by the power chip to control the drive switch tube is large enough, and avoids the drive switch tube from overheating and being damaged because it cannot be fully turned on due to a low voltage of the drive signal.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0032] Please refer to Figure 1 , Figure 1 A schematic diagram of a drive control circuit provided in this application includes a voltage comparison circuit and a switching circuit;

[0033] The input terminal of the voltage comparator circuit is connected to the power supply terminal of the power chip, and is used to output a turn-on signal when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switch Q1.

[0034] The first terminal of the switching circuit is connected to the drive signal output terminal of the power supply chip, and the second terminal is connected to the control terminal of the drive switching transistor Q1. The control terminal is connected to the output terminal of the voltage comparator circuit. When a conduction signal is received, the circuit between the drive signal output terminal of the power supply chip and the control terminal of the drive switching transistor Q1 is turned on, so that the power supply chip outputs a drive signal to control the drive switching transistor Q1.

[0035] In existing technology, the drive signal output terminal of the power supply chip is directly connected to the control terminal of the drive switch Q1. When the power supply chip is powered on, it immediately outputs a drive signal to control the drive switch Q1, so that the drive switch Q1 is turned on or off based on the drive signal, thereby converting the DC bus voltage into pulsed DC current, thus providing auxiliary power to the devices in the photovoltaic inverter and enabling the photovoltaic inverter to perform voltage conversion. However, the power supply chip has a wide operating voltage range, such as 9V to 20V, but the voltage range required for the drive switch Q1 to be fully turned on is smaller. For example, when the voltage of the drive signal output by the power supply chip is 15V, the drive switch Q1 can be turned on normally, but once the voltage of the drive signal is less than 15V, the drive switch Q1 cannot be fully turned on, which will cause the on-resistance of the drive switch Q1 to increase, resulting in abnormal heating. However, the voltage of the drive signal output by the power supply chip is related to its supply voltage. When the voltage at the power supply terminal of the power supply chip is 10V, the power supply chip can power on and work normally, but the voltage of its output drive signal does not exceed 10V. At this time, although the drive switch Q1 can perform the on / off action, it cannot be fully turned on, which will cause abnormal heat generation. In addition, since the power supply chip also draws power from the DC bus, and the voltage on the DC bus fluctuates due to the fluctuations in the DC power output from the photovoltaic panel, the voltage at the power supply terminal of the power supply chip will also fluctuate accordingly, which in turn causes fluctuations in the voltage of the drive signal that controls the drive switch Q1.

[0036] Based on this, a switching circuit is provided between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor Q1 in this application. The switching circuit controls the conduction and cutoff of the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor Q1. The conduction and cutoff of the switching circuit are controlled by a voltage comparator circuit. Specifically, the input terminal of the voltage comparator circuit is connected to the power supply terminal of the power chip. When the voltage of the power supply terminal of the power chip is not less than the preset drive voltage of the drive switching transistor Q1, the voltage of the drive signal output by the power chip is sufficient to fully turn on the drive switching transistor Q1. At this time, the voltage comparator circuit outputs a conduction signal, which causes the switching circuit to connect the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor Q1. Then the power chip can control the conduction and cutoff of the drive switching transistor Q1. However, if the voltage at the power supply terminal of the power chip is less than the preset drive voltage of the drive switch Q1, the voltage comparison circuit will not output a turn-on signal. At this time, the switching circuit will also be turned off, thereby turning off the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switch Q1. Although the power chip is powered on, the drive switch Q1 remains in the off state to avoid abnormal heating due to the drive switch Q1 not being able to be fully turned on.

[0037] In summary, the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switch Q1 is only turned on when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switch Q1. This ensures that the voltage of the drive signal used by the power chip to control the drive switch Q1 is large enough, and prevents the drive switch Q1 from overheating and being damaged because the voltage of the drive signal is too small to be fully turned on.

[0038] Based on the above embodiments:

[0039] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the specific structure of a drive control circuit provided in this application. Figure 2 In this context, VCC is the voltage at the power supply terminal of the power chip, Vg is the drive signal output terminal of the power chip, and Vg1 is the control terminal for driving the switching transistor.

[0040] In a preferred embodiment, the voltage comparison circuit includes a first voltage divider resistor R10, a second voltage divider resistor R11, a pull-up resistor R12, and a voltage comparison unit;

[0041] The first end of the first voltage divider resistor R10 and the first end of the pull-up resistor R12 are connected and connected to the power supply terminal of the power chip.

[0042] The second end of the first voltage divider resistor R10 is connected to the first end of the second voltage divider resistor R11, and the second end of the second voltage divider resistor R11 is grounded.

[0043] The control terminal of the voltage comparator is connected to the second terminal of the first voltage divider resistor R10, the first terminal of the voltage comparator is connected to the second terminal of the pull-up resistor R12, the second terminal of the voltage comparator is grounded, and the first terminal of the voltage comparator is connected to the control terminal of the switching circuit.

[0044] The voltage comparison unit is used to conduct the circuit between its first and second terminals when the voltage at its control terminal is not less than the preset turn-on voltage, so as to output a turn-on signal to the control terminal of the switching circuit.

[0045] The preset turn-on voltage is the voltage across the second voltage divider resistor R11 when the voltage at the power supply terminal of the power chip is the preset drive voltage.

[0046] In the voltage comparison circuit, the first voltage divider resistor R10 and the second voltage divider resistor R11 are connected in series between the power supply terminal and the ground terminal of the power chip. The voltage at the control terminal of the voltage comparison unit is the voltage across the second voltage divider resistor R11. When the voltage at the power supply terminal of the power chip is less than the preset drive voltage, the voltage across the second voltage divider resistor R11 is less than the preset turn-on voltage, and the voltage comparison unit does not conduct. The voltage at the control terminal of the switching circuit is pulled up by the pull-up resistor R12 to the voltage at the power supply terminal of the power chip. Although the voltage at the power supply terminal of the power chip is less than the preset drive voltage at this time, the voltage at the power supply terminal is enough to make the power chip work, and it has not yet fallen to the power chip's turn-off voltage. If the voltage VCC at the power supply terminal of the power chip is not less than the preset drive voltage, then the voltage across the second voltage divider resistor R11 will not be less than the preset turn-on voltage. The voltage comparator unit will then conduct, pulling the control terminal of the switching circuit low. This will turn on the switching circuit and connect the drive signal output terminal of the power chip to the control terminal of the drive switch Q1. Figure 2 Vg and Vg1 are connected in the equation.

[0047] In a preferred embodiment, the voltage comparator is a TL431.

[0048] The TL431 is an adjustable precision reference voltage source. As a voltage comparator, the R terminal of the TL431 is the input terminal of the voltage comparator unit, and the A terminal is the output terminal of the voltage comparator unit, which is connected to the control terminal of the switching circuit. The K terminal of the TL431 is grounded. When the voltage at the R terminal of the TL431 is greater than its internal reference voltage, the A and K terminals of the TL431 conduct, thereby pulling down the level of the control terminal of the switching circuit, and thus conducting between the first and second terminals of the switching circuit. Therefore, by setting the resistance values ​​of the first voltage divider resistor R10 and the second voltage divider resistor R11, when the supply voltage of the power chip is the preset drive voltage, the voltage across the second voltage divider resistor R11 is the preset conduction voltage, which is also the reference voltage of the TL431. For example, if the preset drive voltage is 12V and the reference voltage of TL431 is 2.5V, then by setting the resistance values ​​of the first voltage divider resistor R10 and the second voltage divider resistor R11, the voltage across the second voltage divider resistor R11 can be set so that when the power supply voltage of the power chip is 12V, the voltage across the second voltage divider resistor R11 is 2.5V.

[0049] Therefore, the TL431 can provide a high-precision, low-drift reference voltage, and its preset turn-on voltage can be easily set by two external resistors. It has a wide range of applications and is very low in cost.

[0050] In a preferred embodiment, the voltage comparison circuit further includes a filter capacitor C6, the first end of which is connected to the first end of the second voltage divider resistor R11, and the second end of which is connected to the second end of the second voltage divider resistor R11.

[0051] In this embodiment, a filter capacitor C6 is also connected in parallel across the second voltage divider resistor R11 to prevent oscillation in the circuit and to filter out reference source noise, resistor thermal noise, and high-frequency noise coupled to the REF terminal from the outside, thereby improving the voltage quality injected into the control terminal of the voltage comparator circuit.

[0052] In a preferred embodiment, the switching circuit includes a control switch Q2. The first terminal of the control switch Q2 is connected to the drive signal output terminal of the power supply chip, and the second terminal is connected to the control terminal of the drive switch Q1. The control terminal is connected to the output terminal of the voltage comparator circuit and is used to turn on when a conduction signal is received.

[0053] By connecting the control switch Q2 between the drive signal output terminal of the power chip and the control terminal of the drive switch Q1, it is ensured that the control switch Q2 is turned on when the voltage comparator circuit outputs a turn-on signal, thereby ensuring that the drive switch Q1 can be fully turned on.

[0054] In a preferred embodiment, the conduction signal is low level;

[0055] The control switch Q2 is a PNP transistor.

[0056] A PNP transistor is selected as the control switch Q2. When the voltage comparator does not output a conduction signal, that is, when the signal output by the voltage comparator is not low, the control switch is not turned on, that is, the PNP transistor is in the off state, so as to ensure that the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switch Q1 is turned off.

[0057] In a preferred embodiment, a current-limiting resistor R14 is also included. The first end of the current-limiting resistor R14 is connected to the drive signal output terminal of the power supply chip, and the second end of the current-limiting resistor R14 is connected to the first end of the control switch Q2.

[0058] In this embodiment, an additional current-limiting resistor R14 is set to prevent the large current surge at the power chip from affecting the normal operation of the drive switch Q1 and to ensure the safety of the drive switch Q1.

[0059] Please refer to Figure 3 , Figure 3 The schematic diagram of a partial structure of an auxiliary power supply provided in this application includes the drive control circuit as described above, as well as a power supply chip U1 and a drive switch Q1.

[0060] For a description of the auxiliary power supply provided by this utility model, please refer to the above embodiments; this utility model will not be described in detail again.

[0061] As a preferred embodiment, it also includes a transformer T1, a charging capacitor, a charging resistor, and a reverse protection diode;

[0062] The first end of the charging resistor is connected to the first end of the DC bus capacitor C1, the second end of the charging resistor is connected to the first end of the charging capacitor, the first end of the charging capacitor is connected to the power supply terminal of the power chip, the first end of the charging capacitor is connected to the cathode of the anti-reverse diode, the anode of the anti-reverse diode is connected to the first end of the secondary coil of transformer T1, the second end of the secondary coil of transformer T1 is connected to the second end of the charging capacitor and grounded, the first end of the primary coil of transformer T1 is connected to the first end of the DC bus capacitor C1, the second end of the primary coil of transformer T1 is connected to the first end of the drive switch Q1, the second end of the drive switch Q1 is grounded, and the second end of the DC bus capacitor C1 is grounded.

[0063] In this embodiment, when the power supply terminal of the power chip draws power from the DC bus, a charging resistor is first connected between the DC bus capacitor C1 and the charging capacitor. The power supply terminal of the power chip is connected to the first end of the charging capacitor. The DC bus capacitor C1 first charges the charging capacitor. As the voltage across the charging capacitor rises, the voltage at the power supply terminal of the power chip also rises until it reaches the operating voltage of the power chip, at which point the power chip is powered on. However, if the voltage at the power supply terminal of the power chip does not reach the preset drive voltage at this time, the switching circuit remains off, the drive switch Q1 also remains off, the primary winding of the transformer T1 is disconnected, and the auxiliary power supply has no voltage output. As the voltage across the charging capacitor rises, the voltage at the power supply terminal of the power chip also rises until it reaches the preset drive voltage, at which point the switching circuit is turned on, and the power chip can output a drive signal to the drive switch Q1. The turning on and off of the drive switch Q1 causes a voltage to be applied to the primary winding of the transformer T1 for voltage output. Because an anti-reverse diode is installed between the charging capacitor and the secondary coil of transformer T1, the current will not flow to the secondary coil of transformer T1 during the charging process of the charging capacitor. After the drive switch Q1 is turned on, the secondary coil of transformer T1 senses the voltage on the primary coil to continue charging the charging capacitor and maintain the voltage across the charging capacitor.

[0064] It should be noted that the charging resistor can be formed by connecting two resistors with large resistance values ​​in series, that is, it includes the first charging resistor R1 and the second charging resistor R2. The charging capacitor can include the first charging capacitor C2 and the second charging capacitor C7. The first end of the second charging capacitor C7 is connected to the power supply terminal of the power chip. The anti-reverse diode also includes the first anti-reverse diode D1 and the second anti-reverse diode D4.

[0065] The transformer's multiple secondary coils are also connected to the load via D2 and C3, and via D3 and C4, respectively.

[0066] As a preferred embodiment, a compensation voltage supply circuit is also included;

[0067] The output of the compensation voltage supply circuit is connected to the compensation terminal of the power chip to provide a compensation voltage to the power chip, so that the power chip outputs a drive signal based on the compensation voltage.

[0068] In this embodiment, an additional compensation voltage supply circuit is provided for the power chip to provide compensation voltage. The power chip outputs a drive signal based on the compensation voltage to further ensure the complete conduction of the drive switch Q1.

[0069] like Figure 3Taking a compensation voltage of 12V as an example, the compensation voltage providing circuit includes a third voltage divider resistor R6 and a fourth voltage divider resistor R8 connected in series between the compensation voltage and the ground terminal. The control terminal of TL431a is connected to the connection point between the third voltage divider resistor R6 and the fourth voltage divider resistor R8. The supplementary filter capacitor C5 and the supplementary filter resistor R7 are connected in series between the connection point between the third voltage divider resistor R6 and the fourth voltage divider resistor R8 and the second terminal of optocoupler U2. The first terminal of TL431a is connected to the compensation voltage through a first compensation pull-up resistor R4 and a second compensation pull-up resistor R5 connected in series. The second terminal of TL431a is grounded. The first terminal of optocoupler U2 is connected to the connection point between the first compensation pull-up resistor R4 and the second compensation pull-up resistor R5. The third terminal of optocoupler U2 is connected to the comp terminal of power chip U1 and connected to the VREF terminal of power chip U1 through a compensation current limiting resistor R9 to input the compensation voltage to the VREF terminal of power chip U1. The fourth terminal of optocoupler U2 is grounded.

[0070] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes said element.

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A drive control circuit, characterized in that, Includes voltage comparison circuits and switching circuits; The input terminal of the voltage comparison circuit is connected to the power supply terminal of the power chip, and is used to output a turn-on signal when the voltage at the power supply terminal of the power chip is not less than the preset drive voltage of the drive switching transistor. The first terminal of the switching circuit is connected to the drive signal output terminal of the power chip, and the second terminal is connected to the control terminal of the drive switching transistor. The control terminal is connected to the output terminal of the voltage comparison circuit. When the conduction signal is received, the circuit between the drive signal output terminal of the power chip and the control terminal of the drive switching transistor is turned on, so that the power chip outputs a drive signal to control the drive switching transistor.

2. The drive control circuit as described in claim 1, characterized in that, The voltage comparison circuit includes a first voltage divider resistor, a second voltage divider resistor, a pull-up resistor, and a voltage comparison unit; The first end of the first voltage divider resistor and the first end of the pull-up resistor are connected, and are also connected to the power supply terminal of the power chip. The second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor, and the second end of the second voltage divider resistor is grounded; The control terminal of the voltage comparison unit is connected to the second terminal of the first voltage divider resistor, the first terminal of the voltage comparison unit is connected to the second terminal of the pull-up resistor, the second terminal of the voltage comparison unit is grounded, and the first terminal of the voltage comparison unit is connected to the control terminal of the switching circuit. The voltage comparison unit is used to conduct the circuit between its first and second terminals when the voltage at its control terminal is not less than the preset conduction voltage, so as to output the conduction signal to the control terminal of the switching circuit. The preset on-state voltage is the voltage across the second voltage divider resistor when the voltage at the power supply terminal of the power chip is the preset drive voltage.

3. The drive control circuit as described in claim 2, characterized in that, The voltage comparison unit is TL431.

4. The drive control circuit as described in claim 2, characterized in that, The voltage comparison circuit further includes a filter capacitor, the first end of which is connected to the first end of the second voltage divider resistor, and the second end of which is connected to the second end of the second voltage divider resistor.

5. The drive control circuit as described in any one of claims 1-4, characterized in that, The switching circuit includes a control switch transistor. The first end of the control switch transistor is connected to the drive signal output terminal of the power chip, and the second end is connected to the control terminal of the drive switch transistor. The control terminal is connected to the output terminal of the voltage comparator circuit and is used to turn on when the conduction signal is received.

6. The drive control circuit as described in claim 5, characterized in that, The conduction signal is at a low level; The control switch is a PNP transistor.

7. The drive control circuit as described in claim 5, characterized in that, It also includes a current-limiting resistor, the first end of which is connected to the drive signal output terminal of the power chip, and the second end of which is connected to the first end of the control switch transistor.

8. An auxiliary power supply, characterized in that, The device includes the drive control circuit as described in any one of claims 1-7, and further includes a power supply chip and a drive switching transistor.

9. The auxiliary power supply as described in claim 8, characterized in that, It also includes transformers, charging capacitors, charging resistors, and reverse protection diodes; The first end of the charging resistor is connected to the first end of the DC bus capacitor, the second end of the charging resistor is connected to the first end of the charging capacitor, the first end of the charging capacitor is connected to the power supply terminal of the power chip, the first end of the charging capacitor is connected to the cathode of the anti-reverse diode, the anode of the anti-reverse diode is connected to the first end of the secondary coil of the transformer, the second end of the secondary coil of the transformer is connected to the second end of the charging capacitor and grounded, the first end of the primary coil of the transformer is connected to the first end of the DC bus capacitor, the second end of the primary coil of the transformer is connected to the first end of the drive switch transistor, the second end of the drive switch transistor is grounded, and the second end of the DC bus capacitor is grounded.

10. The auxiliary power supply as described in claim 8, characterized in that, It also includes a compensation voltage supply circuit; The output terminal of the compensation voltage providing circuit is connected to the compensation terminal of the power chip, and is used to provide a compensation voltage to the power chip so that the power chip outputs a drive signal based on the compensation voltage.

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