Low-cost high-voltage bleeder circuit
By designing a discharge circuit with low-power MOSFETs connected in series, combined with Zener diodes and optocoupler control, the problems of high material cost and difficult selection in high-voltage discharge circuits are solved, achieving the effect of low-cost high-voltage discharge.
Patent Information
- Application Number
- CN202520112681.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-01-16
AI Technical Summary
The high voltage withstand requirements of power devices in high-voltage discharge circuits lead to high material costs and difficulty in selection, which is difficult to solve effectively with existing technologies.
The circuit design employs multiple low-voltage power MOSFETs connected in series at a low cost. It combines a unidirectional Zener diode, a drive optocoupler, a start-up MOSFET, a voltage divider circuit, and a resistor branch. Through the series connection of the power MOSFETs and resistors, protection is provided by a protection Zener diode and a reverse diode. Circuit control is achieved in conjunction with an NPN transistor and a filter capacitor.
It achieves low-cost high-voltage discharge, solves the problems of high material cost and difficulty in selection of high-voltage power devices, and improves the reliability and economy of the circuit.
Smart Images
Figure CN223942413U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power electronics and is applied to positive high voltage or negative high voltage discharge circuits. In particular, it relates to a novel low-cost discharge circuit with multiple low-voltage power consumption MOSFETs connected in series. Background Technology
[0002] Power devices in high-voltage discharge circuits, such as MOSFETs, are used in discharge applications. Figure 1 As shown. In high-voltage output applications, the withstand voltage of a single transistor needs to be particularly high. The higher the withstand voltage of a power device, the more expensive the materials become. For example, the price difference between a 1000V power MOSFET and a 4500V power MOSFET can be tens to hundreds of times. Furthermore, high-voltage power devices are scarce, making selection very difficult. Utility Model Content
[0003] To address the shortcomings of existing technologies, this invention provides a low-cost high-voltage discharge circuit.
[0004] The discharge circuit includes a unidirectional Zener diode, a driver optocoupler U10, a startup MOSFET, a voltage divider circuit, and multiple power-dissipating resistors, a drive resistor, a grounding resistor, and power-dissipating MOSFETs. The power-dissipating resistors are connected in series to form a resistor branch. The inputs and outputs of the power-dissipating MOSFETs are connected in series to form a power-dissipating MOSFET branch. The resistor branch is connected to the power-dissipating MOSFET branch. The gate (G) of the first power-dissipating MOSFET in the power-dissipating MOSFET branch is connected to the anode of the unidirectional Zener diode via a drive resistor. The cathode of the unidirectional Zener diode is connected to the junction between the resistor branch and the power-dissipating MOSFET branch. The gate of the first power-dissipating MOSFET is connected to the anode of the remaining resistors via another resistor. A driving resistor is connected to the gate (G) of the next power MOSFET, and so on until the gate of the last power MOSFET is connected. The source (S) of the last power MOSFET in the power MOSFET branch is grounded through a grounding resistor, and the gate (G) is grounded through another grounding resistor. One end of the controlled terminal of the driving optocoupler U10 is connected to VCC, and the other end is connected to the gate (G) of the last power MOSFET. The control terminal of the driving optocoupler U10 is used to receive external control levels. The DC power supply VCC is output as a voltage divider circuit and connected to the gate (G) of the start-up MOSFET. The source (S) of the start-up MOSFET is grounded, and the drain (D) is connected to the source (S) of the last power MOSFET.
[0005] In this configuration, the source (S) terminal of each power MOSFET is connected to the anode of a protection Zener diode, and the cathode of the protection Zener diode is connected to the gate (G) terminal of the power MOSFET.
[0006] In this configuration, a reverse diode is connected between the drain and source terminals of each power-consuming MOSFET.
[0007] Among them, a filter capacitor C64 is connected between the gate and source of the MOSFET.
[0008] This includes an NPN transistor Q7, resistors R59, R81, and R76, and a low-voltage power supply. The emitter of the NPN transistor Q7 is grounded, and its collector is connected to the cathode of the LED driving the optocoupler U10. The anode of the LED is connected to the low-voltage power supply via resistor R59. The base of the NPN transistor Q7 receives the external control level via resistor R76. Resistor R81 is connected between the base and emitter of the NPN transistor Q7.
[0009] In this circuit, a filter capacitor C67 is connected between the base and emitter of the NPN transistor Q7.
[0010] The circuit of this invention realizes the series discharge of multiple low-voltage MOS, and at the same time solves the problems of high material cost and difficulty in selecting power devices. Attached Figure Description
[0011] Figure 1 The discharge circuit of a conventional high-voltage single-power device is shown.
[0012] Figure 2 The power device series discharge circuit of this invention is shown. Detailed Implementation
[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.
[0014] The discharge circuit includes a unidirectional Zener diode, a driver optocoupler U10, a startup MOSFET, a voltage divider circuit, and multiple power-dissipating resistors, a drive resistor, a grounding resistor, and power-dissipating MOSFETs. The power-dissipating resistors are connected in series to form a resistor branch. The inputs and outputs of the power-dissipating MOSFETs are connected in series to form a power-dissipating MOSFET branch. The resistor branch is connected to the power-dissipating MOSFET branch. The gate (G) of the first power-dissipating MOSFET in the power-dissipating MOSFET branch is connected to the anode of the unidirectional Zener diode via a drive resistor. The cathode of the unidirectional Zener diode is connected to the junction between the resistor branch and the power-dissipating MOSFET branch. The gate of the first power-dissipating MOSFET is connected to the anode of the remaining resistors via another resistor. A driving resistor is connected to the gate (G) of the next power MOSFET, and so on until the gate of the last power MOSFET is connected. The source (S) of the last power MOSFET in the power MOSFET branch is grounded through a grounding resistor, and the gate (G) is grounded through another grounding resistor. One end of the controlled terminal of the driving optocoupler U10 is connected to VCC, and the other end is connected to the gate (G) of the last power MOSFET. The control terminal of the driving optocoupler U10 is used to receive external control levels. The DC power supply VCC is output as a voltage divider circuit and connected to the gate (G) of the start-up MOSFET. The source (S) of the start-up MOSFET is grounded, and the drain (D) is connected to the source (S) of the last power MOSFET.
[0015] When powered on, transistor Q6 is turned on first, and then the external OFF_1 signal controls the drive of optocoupler U10, which provides the drive signal for the power-consuming MOSFETs. Q5→Q3→Q2→Q1 are turned on in sequence, and finally the energy on the bus is consumed through the resistor.
[0016] Furthermore, the source (S) terminal of each power MOSFET is connected to the anode of a protection Zener diode, and the cathode of the protection Zener diode is connected to the gate (G) terminal of the power MOSFET, serving as the gate-source (GS) protection for the power MOSFET. A reverse diode is connected across the drain (DS) terminals of each power MOSFET.
[0017] Furthermore, a filter capacitor C64 is connected between the gate and source of the MOSFET.
[0018] The discharge circuit also includes NPN transistor Q7, resistor R59, resistor R81, resistor R76, and low-voltage power supply;
[0019] The emitter of NPN transistor Q7 is grounded, and its collector is connected to the cathode of the LED driving optocoupler U10. The anode of the LED is connected to a low-voltage power supply via resistor R59. The base of NPN transistor Q7 receives the external control level via resistor R76. Resistor R81 is connected between the base and emitter of NPN transistor Q7. NPN transistor Q7 amplifies the current, driving the LED to turn on and off. Filter capacitor C67 is connected between the base and emitter of NPN transistor Q7.
[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.
Claims
1. A low-cost high-voltage discharge circuit, characterized in that: This circuit includes a unidirectional Zener diode, a driver optocoupler U10, a startup MOSFET, a voltage divider circuit, and multiple power-dissipating resistors, driver resistors, grounding resistors, and power-dissipating MOSFETs. The power-dissipating resistors are connected in series to form a resistor branch, and the inputs and outputs of the power-dissipating MOSFETs are sequentially connected in series to form a power-dissipating MOSFET branch. The resistor branch is connected to the power-dissipating MOSFET branch. The gate (G) of the first power-dissipating MOSFET in the power-dissipating MOSFET branch is connected to the anode of the unidirectional Zener diode via a driver resistor. The cathode of the unidirectional Zener diode is connected to the junction between the resistor branch and the power-dissipating MOSFET branch. The gate of the first power-dissipating MOSFET is connected to the anode of the remaining power-dissipating MOSFET via another driver resistor. The moving resistor is connected to the gate (G) of the next power MOSFET, and so on until the gate of the last power MOSFET is connected. The source (S) of the last power MOSFET in the power MOSFET branch is grounded through a grounding resistor, and the gate (G) is grounded through another grounding resistor. One end of the controlled terminal of the drive optocoupler U10 is connected to VCC, and the other end is connected to the gate (G) of the last power MOSFET. The control terminal of the drive optocoupler U10 is used to receive external control levels. The DC power supply VCC is output as a voltage divider circuit and connected to the gate (G) of the start-up MOSFET. The source (S) of the start-up MOSFET is grounded, and the drain (D) is connected to the source (S) of the last power MOSFET.
2. The low-cost high-voltage discharge circuit according to claim 1, characterized in that: The source (S) of each power MOSFET is connected to the anode of a protection Zener diode, and the cathode of the protection Zener diode is connected to the gate (G) of the power MOSFET.
3. The low-cost high-voltage discharge circuit according to claim 2, characterized in that: A reverse diode is connected between the drain and source of each power MOSFET.
4. The low-cost high-voltage discharge circuit according to claim 1, characterized in that: Connect a filter capacitor C64 between the gate and source of the MOSFET to start it up.
5. The low-cost high-voltage discharge circuit according to claim 1, characterized in that: The circuit includes an NPN transistor Q7, resistors R59, R81, and R76, and a low-voltage power supply. The emitter of the NPN transistor Q7 is grounded, and its collector is connected to the cathode of the LED driving the optocoupler U10. The anode of the LED is connected to the low-voltage power supply via resistor R59. The base of the NPN transistor Q7 receives the external control level via resistor R76. Resistor R81 is connected between the base and emitter of the NPN transistor Q7.
6. The low-cost high-voltage discharge circuit according to claim 5, characterized in that: A filter capacitor C67 is connected between the base and emitter of the NPN transistor Q7.