Brake power supply circuit, circuit board assembly and elevator control cabinet

Abstract

The utility model relates to the technical field of elevators, and discloses a brake power supply circuit, a circuit board assembly and an elevator control cabinet, the brake power supply circuit comprises a zero sequence current transformer, a first sampling resistor, an amplification unit, a comparison unit, a control unit, a rectification unit and a DC-DC converter; the first output end and the second output end of the zero sequence current transformer are connected with the first input end and the second input end of the rectification unit. The first output end and the second output end of the rectification unit are connected with the first input end and the second input end of the DC-DC converter. The first sampling end and the second sampling end of the zero sequence current transformer are connected with the two ends of the first sampling resistor, the two ends of the first sampling resistor are further connected with the first input end and the second input end of the amplification unit, the output end of the amplification unit is connected with the input end of the comparison unit, and the output end of the comparison unit is connected with the control unit. The control unit is connected with the control end of the DC-DC converter; therefore, the small-size design and the maintenance convenience of the elevator brake are both considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the elevator technical field, and particularly relates to a brake power supply circuit, a circuit board assembly and an elevator control cabinet. BACKGROUND

[0002] In an elevator system, a brake is a key component for safety. If a short circuit to ground occurs in the winding of the brake or a line providing power for the winding of the brake, the brake cannot work normally, and thus a safety-related problem occurs. Therefore, when a short circuit to ground occurs in the brake and the power supply circuit, the elevator system needs to provide a protection function to make the brake in a closed state and ensure safety.

[0003] In the prior art, a leakage protector or a fuse is usually added in the power supply circuit of the brake to realize protection against a short circuit to ground in the brake and the power supply circuit. However, the leakage protector occupies a large space in the system and has a high cost. The fuse is not recoverable when a fault occurs each time, and maintenance personnel need to configure different types of fuses, which is not conducive to on-site maintenance. Therefore, the prior art cannot take into account the small size design of the elevator brake and the convenience of maintenance when realizing the protection against a short circuit to ground in the brake and the power supply circuit. CONTENT OF THE INVENTION

[0004] The purpose of the embodiments of the present application is to provide a brake power supply circuit, a circuit board assembly and an elevator control cabinet, so as to take into account the small size design of the elevator brake and the convenience of maintenance.

[0005] To solve the above technical problems, the embodiment of the present application provides a brake power supply circuit, comprising: a zero sequence current transformer, a first sampling resistor, an amplification unit, a comparison unit, a control unit, a rectification unit, a DC-DC converter; the first input end and the second input end of the zero sequence current transformer are used as input interfaces of the brake power supply circuit; the first output end and the second output end of the zero sequence current transformer are connected with the first input end and the second input end of the rectification unit respectively, the first output end and the second output end of the rectification unit are connected with the first input end and the second input end of the DC-DC converter respectively, and the first output end and the second output end of the DC-DC converter are used as output interfaces of the brake power supply circuit; the output interfaces of the brake power supply circuit are configured to be connected with an elevator brake; the first sampling end and the second sampling end of the zero sequence current transformer are connected with the first end and the second end of the first sampling resistor respectively, the first end and the second end of the first sampling resistor are also connected with the first input end and the second input end of the amplification unit respectively, the output end of the amplification unit is connected with the input end of the comparison unit, the output end of the comparison unit is connected with the first end of the control unit, and the second end of the control unit is connected with the control end of the DC-DC converter.

[0006] The embodiment of the present application also provides a circuit board assembly, comprising: the brake power supply circuit as described above.

[0007] The embodiment of the present application also provides an elevator control cabinet, comprising: the circuit board assembly as described above.

[0008] In some embodiments, the amplification unit comprises: a second resistor, a third resistor, a fourth resistor, a fifth resistor and an operational amplifier AMP; the first end of the second resistor is used as the first input end of the amplification unit, the second end of the second resistor is connected with the positive input end of the AMP, the first end of the third resistor is used as the second input end of the amplification unit, and the second end of the third resistor is connected with the negative input end of the AMP; the first end of the fourth resistor is connected with the second end of the second resistor, and the second end of the fourth resistor is connected with a first power supply; the first end of the fifth resistor is connected with the second end of the third resistor, the second end of the fifth resistor is connected with the output end of the AMP, and the output end of the AMP is used as the output end of the amplification unit.

[0009] In some embodiments, the comparison unit comprises: a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first comparator, a second comparator, a first diode, a second diode; an anode of the first diode is connected to a cathode of the second diode, a node between the anode of the first diode and the cathode of the second diode is an input terminal of the comparison unit; a cathode of the first diode is connected to a first terminal of the sixth resistor, a second terminal of the sixth resistor is grounded, the cathode of the first diode is also connected to a first terminal of the seventh resistor, a second terminal of the seventh resistor is connected to a negative input terminal of the first comparator, a positive input terminal of the first comparator is configured to receive a first reference voltage; an anode of the second diode is connected to a first terminal of the eighth resistor, a second terminal of the eighth resistor is connected to a second power supply, the anode of the second diode is also connected to a first terminal of the ninth resistor, a second terminal of the ninth resistor is connected to a positive input terminal of the second comparator, a negative input terminal of the second comparator is configured to receive a second reference voltage; an output terminal of the first comparator and an output terminal of the second comparator are collectively an output terminal of the comparison unit; the output terminal of the first comparator and the output terminal of the second comparator are also collectively connected to a first terminal of the tenth resistor, a second terminal of the tenth resistor is connected to the second power supply.

[0010] In some embodiments, the zero sequence current transformer comprises: a first winding, a second winding, an induction winding; a first terminal of the first winding is a first input terminal of the zero sequence current transformer, a second terminal of the first winding is a first output terminal of the zero sequence current transformer; a first terminal of the second winding is a second input terminal of the zero sequence current transformer, a second terminal of the second winding is a second output terminal of the zero sequence current transformer; the induction winding is oppositely arranged with the first winding and the second winding respectively, a first terminal of the induction winding is a first sampling terminal of the zero sequence current transformer, a second terminal of the induction winding is a second sampling terminal of the zero sequence current transformer.

[0011] In some embodiments, the rectification unit comprises: a third diode, a fourth diode, a fifth diode, a sixth diode; an anode of the third diode is connected to a cathode of the fourth diode, a node between the anode of the third diode and the cathode of the fourth diode is a first input terminal of the rectification unit; an anode of the fifth diode is connected to a cathode of the sixth diode, a node between the anode of the fifth diode and the cathode of the sixth diode is a second input terminal of the rectification unit; a cathode of the third diode and a cathode of the fifth diode are collectively a first output terminal of the rectification unit; an anode of the fourth diode and an anode of the sixth diode are collectively a second output terminal of the rectification unit.

[0012] In some embodiments, the DC-DC converter includes: a switching transistor, an inductor, and a seventh diode; the source of the switching transistor serves as the first input terminal of the DC-DC converter, the drain of the switching transistor is connected to the first terminal of the inductor, and the second terminal of the inductor serves as the first output terminal of the DC-DC converter; a node between the drain of the switching transistor and the first terminal of the inductor is connected to the cathode of the seventh diode; the second input terminal of the DC-DC converter is connected to the second output terminal of the DC-DC converter, and any node between the second input terminal and the second output terminal of the DC-DC converter is connected to the anode of the seventh diode; the gate of the switching transistor serves as the control terminal of the DC-DC converter.

[0013] In some embodiments, the voltage of the first power supply is 1.65V.

[0014] In some embodiments, the amplification unit is configured to output an AC signal; the first reference voltage is the maximum voltage value of the AC signal, and the second reference voltage is the minimum voltage value of the AC signal.

[0015] The technical solution provided in this application has at least the following advantages:

[0016] This application detects the short-circuit current to ground of the elevator control cabinet using a zero-sequence current transformer. After sampling the short-circuit voltage to ground through a first sampling resistor, it is amplified by an amplification unit. The comparison unit makes a judgment based on the amplified voltage, and the control unit controls the start and stop of the DC-DC converter, thereby realizing the short-circuit protection function of the elevator control cabinet. At the same time, the entire brake power supply circuit occupies a smaller volume compared to existing leakage current protection devices, and the brake power supply circuit does not require fuses, which is beneficial for on-site maintenance. Thus, it takes into account both the small size design of the elevator brake and the convenience of maintenance. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a schematic diagram of the circuit structure of a brake power supply circuit according to an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the specific circuit structure of a brake power supply circuit according to an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0021] One embodiment of this application relates to a brake power supply circuit, the specific circuit structure diagram of which is shown below. Figure 1 As shown, the brake power supply circuit includes: a zero-sequence current transformer (ZCL) 101, a first sampling resistor R1, an amplification unit 102, a comparison unit 103, a control unit 104, a rectification unit 105, and a DC-DC converter 106.

[0022] Specifically, the first and second input terminals of the zero-sequence current transformer 101 serve as the input interfaces of the brake power supply circuit; the first and second output terminals of the zero-sequence current transformer 101 are respectively connected to the first and second input terminals of the rectifier unit 105, and the first and second output terminals of the rectifier unit 105 are respectively connected to the first and second input terminals of the DC-DC converter 106, and the first and second output terminals of the DC-DC converter 106 serve as the output interfaces of the brake power supply circuit; the output interface of the brake power supply circuit is configured to connect to the elevator brake; the first and second sampling terminals of the zero-sequence current transformer 101 are respectively connected to the first and second terminals of the first sampling resistor R1, and the first and second terminals of the first sampling resistor R1 are also respectively connected to the first and second input terminals of the amplification unit 102; the output terminal of the amplification unit 102 is connected to the input terminal of the comparison unit 103; the output terminal of the comparison unit 103 is connected to the first terminal of the control unit 104; and the second terminal of the control unit 104 is connected to the control terminal of the DC-DC converter 106.

[0023] In this embodiment, the short-circuit current to ground of the elevator control cabinet is detected by the zero-sequence current transformer 101. After the short-circuit voltage to ground is sampled by the first sampling resistor R1, it is amplified by the amplification unit 102. The comparison unit 103 makes a judgment based on the amplified voltage, and the control unit 104 controls the start and stop of the DC-DC converter 106, thereby realizing the short-circuit protection function of the elevator control cabinet. At the same time, the entire brake power supply circuit occupies a smaller volume compared with the existing leakage current protection device. Furthermore, the brake power supply circuit does not require the installation of fuses, which is beneficial for on-site maintenance. Thus, the small size design and maintenance convenience of the elevator brake are taken into account.

[0024] Specifically, the zero-sequence current transformer 101 includes: a first winding L1, a second winding L2, and an induction winding L3; the first end of the first winding L1 serves as the first input terminal of the zero-sequence current transformer 101, and the second end of the first winding L1 serves as the first output terminal of the zero-sequence current transformer 101; the first end of the second winding L2 serves as the second input terminal of the zero-sequence current transformer 101, and the second end of the second winding L2 serves as the second output terminal of the zero-sequence current transformer 101; the induction winding L3 is respectively arranged opposite to the first winding L1 and the second winding L2, the first end of the induction winding L3 serves as the first sampling terminal of the zero-sequence current transformer 101, and the second end of the induction winding L3 serves as the second sampling terminal of the zero-sequence current transformer 101.

[0025] Specifically, the rectifier unit 105 includes: a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6; the anode of the third diode D3 is connected to the cathode of the fourth diode D4, and a node between the anode of the third diode D3 and the cathode of the fourth diode D4 serves as the first input terminal of the rectifier unit 105; the anode of the fifth diode D5 is connected to the cathode of the sixth diode D6, and a node between the anode of the fifth diode D5 and the cathode of the sixth diode D6 serves as the second input terminal of the rectifier unit 105; the cathodes of the third diode D3 and the fifth diode D5 together serve as the first output terminal of the rectifier unit 105; and the anodes of the fourth diode D4 and the sixth diode D6 together serve as the second output terminal of the rectifier unit 105. The DC-DC converter 106 includes: a switching transistor Q, an inductor L, and a seventh diode D7; the source of the switching transistor Q serves as the first input terminal of the DC-DC converter 106, the drain of the switching transistor Q is connected to the first terminal of the inductor L, and the second terminal of the inductor L serves as the first output terminal of the DC-DC converter 106; a node between the drain of the switching transistor Q and the first terminal of the inductor L is connected to the cathode of the seventh diode D7; the second input terminal of the DC-DC converter 106 is connected to the second output terminal of the DC-DC converter 106, and either node between the second input terminal and the second output terminal of the DC-DC converter 106 is connected to the anode of the seventh diode D7; the gate of the switching transistor Q serves as the control terminal of the DC-DC converter 106.

[0026] In practical applications, the first and second input terminals of the zero-sequence current transformer 101 are connected to the live wire L and neutral wire N of the input interface, respectively. When the elevator brake is working normally, the currents in the live wire L and neutral wire N are equal, and no current is generated in the induction winding L3. When the elevator brake is short-circuited to ground, the currents in the live wire L and neutral wire N are unequal, and a current is generated in the induction winding L3. This current signal is sampled by the first sampling resistor R1 and converted into a voltage signal. The signal is then amplified by the amplification unit 102 and compared by the comparison unit 103 to determine whether a limit is exceeded. If the limit is exceeded, the comparison unit 103 will output a fault signal. After receiving the fault signal, the control unit 104 controls the switch Q of the DC-DC converter 106 to turn off and enter a fault-locked state, thereby realizing the short-circuit protection function of the elevator brake to ground. Specifically, the switch Q is an NMOS transistor.

[0027] like Figure 2The diagram shown is a schematic of the specific circuit structure of the brake power supply circuit in this embodiment. The amplification unit 102 in this embodiment includes: a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and an operational amplifier AMP. The first end of the second resistor R2 serves as the first input terminal of the amplification unit 102, and the second end of the second resistor R2 is connected to the positive input terminal of the operational amplifier AMP. The first end of the third resistor R3 serves as the second input terminal of the amplification unit 102, and the second end of the third resistor R3 is connected to the negative input terminal of the operational amplifier AMP. The first end of the fourth resistor R4 is connected to the second end of the second resistor R2, and the second end of the fourth resistor R4 is connected to the first power supply. The first end of the fifth resistor R5 is connected to the second end of the third resistor R3, and the second end of the fifth resistor R5 is connected to the output terminal of the operational amplifier AMP. The output terminal of the operational amplifier AMP serves as the output terminal of the amplification unit 102.

[0028] Specifically, the comparator unit 103 includes: a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first comparator COMP1, a second comparator COMP2, a first diode D1, and a second diode D2; the anode of the first diode D1 is connected to the cathode of the second diode D2, and a node between the anode of the first diode D1 and the cathode of the second diode D2 serves as the input terminal of the comparator unit 103; the cathode of the first diode D1 is connected to the first terminal of the sixth resistor R6, the second terminal of the sixth resistor R6 is grounded, the cathode of the first diode D1 is also connected to the first terminal of the seventh resistor R7, the second terminal of the seventh resistor R7 is connected to the negative input terminal of the first comparator COMP1, and the positive input terminal of the first comparator COMP1 is... The device is configured to receive a first reference voltage VREF1; the anode of the second diode D2 is connected to the first terminal of the eighth resistor R8, the second terminal of the eighth resistor R8 is connected to the second power supply VCC, the anode of the second diode D2 is also connected to the first terminal of the ninth resistor R9, the second terminal of the ninth resistor R9 is connected to the positive input terminal of the second comparator COMP2, and the negative input terminal of the second comparator COMP2 is configured to receive the second reference voltage VREF2; the output terminals of the first comparator COMP1 and the second comparator COMP2 together serve as the output terminals of the comparison unit 103; the output terminals of the first comparator COMP1 and the second comparator COMP2 are also connected to the first terminal of the tenth resistor R10, and the second terminal of the tenth resistor R10 is connected to the second power supply VCC.

[0029] In practical applications, the first and second input terminals of the zero-sequence current transformer 101 are connected to the live wire L and neutral wire N of the input interface, respectively. When the elevator brake is working normally, the currents of the live wire L and neutral wire N are equal, and no current is generated in the induction winding L3. When the elevator brake is short-circuited to ground, the currents of the live wire L and neutral wire N are not equal, and a current is generated in the induction winding L3. The current signal generated in the induction winding L3 is converted into a voltage signal by sampling through the first sampling resistor R1.

[0030] The amplifier circuit 102 consists of a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and an operational amplifier AMP. The second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the operational amplifier AMP form a differential signal amplifier circuit. The differential signal amplifier circuit amplifies the voltage across the first sampling resistor R1. The amplified voltage is alternating current. By connecting a first power supply with a voltage of 1.65V to the second terminal of the fourth resistor R4, the zero point of the alternating current can be raised to 1.65V, so that the amplified alternating current can be within the positive voltage range, so that the subsequent comparison unit 103 can perform threshold comparison.

[0031] The comparator unit 103 consists of a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first comparator COMP1, a second comparator COMP2, a first diode D1, and a second diode D2. The sixth resistor R6, seventh resistor R7, eighth resistor R8, ninth resistor R9, tenth resistor R10, first comparator COMP1, second comparator COMP2, first diode D1, and second diode D2 form a window-type comparator. The output signal of the amplification unit 102 passes through the first diode D1 and the seventh resistor R7 and enters the inverting input terminal of the first comparator COMP1, where it is compared with the first... The first comparator COMP1 outputs a low level when the voltage is higher than the first reference voltage VREF1. The output signal of the amplifier circuit 102 passes through the second diode D2 and the ninth resistor R9 and enters the non-inverting input of the second comparator COMP2, which is compared with the second reference voltage VREF2. When the voltage is lower than the second reference voltage VREF2, the output of the second comparator COMP2 outputs a low level. After receiving the low-level signal output by the comparator unit 103, the control unit 104 turns off the switch of the DC-DC converter 106 and locks it in the off state, thereby realizing the output short-circuit protection function.

[0032] It should be noted that the amplification unit 102 is configured to output an AC signal. The AC signal only needs to meet one of the following conditions: higher than the first reference voltage VREF1 and lower than the second reference voltage VREF2. Therefore, in this embodiment, the first reference voltage VREF1 is set as the maximum voltage value of the AC signal, and the second reference voltage VREF2 is set as the minimum voltage value of the AC signal. That is, when the AC signal exceeds the range defined by the sine wave of the AC signal, the comparison unit 103 will output a low-level signal to make the control unit 104 turn off the switching transistor of the DC-DC converter 106, thereby realizing the short-circuit protection function to ground of the elevator control cabinet.

[0033] Another aspect of this application provides a circuit board assembly, including: a brake power supply circuit as described in any of the above embodiments.

[0034] It is not difficult to see that this embodiment is a circuit board assembly embodiment corresponding to the circuit embodiment, and this embodiment can be implemented in conjunction with the circuit embodiment. The relevant technical details mentioned in the circuit embodiment are still valid in this embodiment, and will not be repeated here to reduce repetition. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the circuit embodiment.

[0035] Furthermore, in order to highlight the innovative aspects of this application, no units that are not closely related to solving the technical problems proposed in this application are introduced in this embodiment, but this does not mean that there are no other units in this embodiment.

[0036] Another aspect of this application provides an elevator control cabinet, including: a circuit board assembly as described in the above embodiment.

[0037] The above division of various components is only for clarity of description. In implementation, they can be combined into one component or some components can be split into multiple components. As long as they include the same logical relationship, they are all within the scope of protection of this patent.

[0038] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A brake power supply circuit, characterized in that, include: Zero-sequence current transformer, first sampling resistor, amplification unit, comparison unit, control unit, rectification unit, DC-DC converter; The first and second input terminals of the zero-sequence current transformer serve as the input interfaces of the brake power supply circuit; the first and second output terminals of the zero-sequence current transformer are respectively connected to the first and second input terminals of the rectifier unit, and the first and second output terminals of the rectifier unit are respectively connected to the first and second input terminals of the DC-DC converter; the first and second output terminals of the DC-DC converter serve as the output interfaces of the brake power supply circuit; the output interfaces of the brake power supply circuit are configured to connect to the elevator brake. The first sampling terminal and the second sampling terminal of the zero-sequence current transformer are respectively connected to the first terminal and the second terminal of the first sampling resistor. The first terminal and the second terminal of the first sampling resistor are also respectively connected to the first input terminal and the second input terminal of the amplification unit. The output terminal of the amplification unit is connected to the input terminal of the comparison unit. The output terminal of the comparison unit is connected to the first terminal of the control unit. The second terminal of the control unit is connected to the control terminal of the DC-DC converter.

2. The brake power supply circuit according to claim 1, characterized in that, The amplification unit includes: a second resistor, a third resistor, a fourth resistor, a fifth resistor, and an operational amplifier AMP; The first end of the second resistor serves as the first input terminal of the amplification unit, the second end of the second resistor is connected to the positive input terminal of the AMP, the first end of the third resistor serves as the second input terminal of the amplification unit, and the second end of the third resistor is connected to the negative input terminal of the AMP. The first end of the fourth resistor is connected to the second end of the second resistor, and the second end of the fourth resistor is connected to the first power supply; the first end of the fifth resistor is connected to the second end of the third resistor, and the second end of the fifth resistor is connected to the output end of the AMP, and the output end of the AMP serves as the output end of the amplification unit.

3. The brake power supply circuit according to claim 1 or 2, characterized in that, The comparison unit includes: a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first comparator, a second comparator, a first diode, and a second diode; The anode of the first diode is connected to the cathode of the second diode, and a node between the anode of the first diode and the cathode of the second diode serves as the input terminal of the comparison unit. The cathode of the first diode is connected to the first terminal of the sixth resistor, the second terminal of the sixth resistor is grounded, the cathode of the first diode is also connected to the first terminal of the seventh resistor, the second terminal of the seventh resistor is connected to the negative input terminal of the first comparator, and the positive input terminal of the first comparator is configured to receive a first reference voltage. The anode of the second diode is connected to the first terminal of the eighth resistor, the second terminal of the eighth resistor is connected to the second power supply, the anode of the second diode is also connected to the first terminal of the ninth resistor, the second terminal of the ninth resistor is connected to the positive input terminal of the second comparator, and the negative input terminal of the second comparator is configured to receive the second reference voltage. The output terminals of the first comparator and the second comparator together serve as the output terminal of the comparison unit. The output terminals of the first comparator and the second comparator are also connected to the first terminal of the tenth resistor, and the second terminal of the tenth resistor is connected to the second power supply.

4. The brake power supply circuit according to claim 1, characterized in that, The zero-sequence current transformer includes: a first winding, a second winding, and an induction winding; the first end of the first winding serves as the first input terminal of the zero-sequence current transformer, and the second end of the first winding serves as the first output terminal of the zero-sequence current transformer. The first end of the second winding serves as the second input terminal of the zero-sequence current transformer, and the second end of the second winding serves as the second output terminal of the zero-sequence current transformer. The induction winding is respectively arranged opposite to the first winding and the second winding. The first end of the induction winding serves as the first sampling end of the zero-sequence current transformer, and the second end of the induction winding serves as the second sampling end of the zero-sequence current transformer.

5. The brake power supply circuit according to claim 1, characterized in that, The rectifier unit includes: a third diode, a fourth diode, a fifth diode, and a sixth diode; The anode of the third diode is connected to the cathode of the fourth diode, and a node between the anode of the third diode and the cathode of the fourth diode serves as the first input terminal of the rectifier unit. The anode of the fifth diode is connected to the cathode of the sixth diode, and a node between the anode of the fifth diode and the cathode of the sixth diode serves as the second input terminal of the rectifier unit. The cathodes of the third diode and the fifth diode together serve as the first output terminal of the rectifier unit. The anodes of the fourth diode and the sixth diode together serve as the second output terminal of the rectifier unit.

6. The brake power supply circuit according to claim 1, characterized in that, The DC-DC converter includes: a switching transistor, an inductor, and a seventh diode; The source of the switching transistor serves as the first input terminal of the DC-DC converter, the drain of the switching transistor is connected to the first terminal of the inductor, and the second terminal of the inductor serves as the first output terminal of the DC-DC converter; a node between the drain of the switching transistor and the first terminal of the inductor is connected to the cathode of the seventh diode. The second input terminal of the DC-DC converter is connected to the second output terminal of the DC-DC converter, and either the second input terminal or the second output terminal of the DC-DC converter is connected to the anode of the seventh diode; the gate of the switching transistor serves as the control terminal of the DC-DC converter.

7. The brake power supply circuit according to claim 2, characterized in that, The voltage of the first power supply is 1.65V.

8. The brake power supply circuit according to claim 3, characterized in that, The amplification unit is configured to output an AC signal; the first reference voltage is the maximum voltage value of the AC signal, and the second reference voltage is the minimum voltage value of the AC signal.

9. A circuit board assembly, characterized in that, include: The brake power supply circuit as described in any one of claims 1 to 8.

10. An elevator control cabinet, characterized in that, include: The circuit board assembly as described in claim 9.

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