Discharging circuit and electronic equipment
By designing a discharge circuit including a first capacitor, a first switch tube, a first resistor, a voltage stabilization tube and a control module, the problem of rapid discharge of high-voltage electrolytic capacitors is solved, and safe constant current discharge when the equipment is powered off is realized, and high efficiency and low power consumption are maintained during normal operation.
Patent Information
- Application Number
- CN202421852105.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-07-30
AI Technical Summary
In the primary and secondary circuits of switching power supplies, the power of high-voltage electrolytic capacitors cannot be discharged quickly, resulting in production operators and after-sales maintenance personnel facing electric shock safety risks. The prior art realizes discharge by increasing the discharge resistance or increasing the static bias current, but this can lead to reduced product efficiency, increased no-load power consumption and increased temperature rise.
A discharge circuit is designed, the circuit including a first capacitor, a first switching tube, a first resistor, a voltage regulator tube and a control module. When the equipment is working normally, the control module makes the first switch tube in the off state and the capacitor does not discharge; when the equipment is powered off, the control module makes the first switch tube in the on state, and the voltage regulator tube and the first resistor jointly realize the constant current discharge of the first capacitor.
Constant current discharge of the first capacitor is achieved when the equipment is powered off to ensure safety, while almost no power consumption is consumed during normal operation of the equipment, avoiding reduced efficiency and increased temperature rise. By adjusting the parameters of the first resistor and the voltage stabilization tube, the discharge current can be finely adjusted, and the discharge time can be controlled and has high accuracy.
Smart Images
Figure CN222940702U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electronic circuits, and particularly to a discharge circuit and an electronic device. Background Art
[0002] There are large electrolytic capacitors in the primary and secondary circuits of a switching power supply. During the production process and after-sales maintenance, if the electricity on the high-voltage electrolytic capacitor cannot be discharged relatively quickly, it will pose a safety risk of electric shock to production operators and after-sales maintenance personnel.
[0003] In some power supply products with high safety requirements, it is required that after the power supply is cut off, the voltage on the high-voltage capacitor in the product circuit needs to drop below 60V within a short time. The prior art passively discharges the capacitor by adding a discharge resistor or increasing the static bias current in the circuit. This approach will bring defects such as a decrease in product efficiency, an increase in no-load power consumption, and an increase in product temperature rise. Summary of the Utility Model
[0004] To solve the above problems, this application provides a discharge circuit and an electronic device, which can perform constant-current discharge on a first capacitor when the device is powered off.
[0005] One technical solution adopted by this application is: to provide a discharge circuit, which includes: a first capacitor, the first end of the first capacitor is connected to a first voltage input terminal, and the second end of the first capacitor is connected to a second voltage input terminal; a first switching tube, the first end of the first switching tube is connected to the first end of the first capacitor; a first resistor, the first end of the first resistor is connected to the second end of the first switching tube, and the second end of the first resistor is connected to the second end of the first capacitor; a zener diode, the cathode of the zener diode is connected to the control terminal of the first switching tube, and the anode of the zener diode is connected to the second end of the first resistor; a control module, connected to the control terminal of the first switching tube, and the control module is configured to: provide a bias voltage to the control terminal of the first switching tube, or pull down the voltage of the control terminal of the first switching tube.
[0006] In one embodiment, the control module includes: a bias unit, the bias unit is connected to the control terminal of the first switching tube, and the bias unit is configured to provide a bias voltage to the control terminal of the first switching tube; a pull-down unit, the pull-down unit is connected to the control terminal of the first switching tube, and the pull-down unit is configured to pull down the voltage of the control terminal of the first switching tube.
[0007] In one embodiment, the bias unit includes: a second resistor, the first end of the second resistor is connected to the first end of the first switching tube, and the second end of the second resistor is connected to the control terminal of the first switching tube.
[0008] In one embodiment, the pull - down unit includes: a second switching transistor, a first end of the second switching transistor is connected to a control end of the first switching transistor, and a second end of the second switching transistor is grounded; a voltage - dividing module, a first end of the voltage - dividing module is configured to receive a control signal, a second end of the voltage - dividing module is grounded, and a voltage - dividing node of the voltage - dividing module is connected to the control end of the second switching transistor.
[0009] In one embodiment, the voltage - dividing module includes: a third resistor, a first end of the third resistor is configured to receive a control signal, and a second end of the third resistor is connected to the control end of the second switching transistor; a fourth resistor, a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is grounded.
[0010] In one embodiment, the pull - down unit further includes: a diode, an anode of the diode is configured to receive a control signal, and a cathode of the diode is connected to the first end of the voltage - dividing module.
[0011] In one embodiment, the pull - down unit further includes: a second capacitor, a first end of the second capacitor is connected to the cathode of the diode, and a second end of the second capacitor is grounded.
[0012] In one embodiment, the second switching transistor is a MOS transistor, a first end of the MOS transistor is connected to the control end of the first switching transistor, a second end of the MOS transistor is grounded, and the control end of the MOS transistor is configured to receive a control signal.
[0013] In one embodiment, the second switching transistor is a triode, a first end of the triode is connected to the control end of the first switching transistor, a second end of the triode is grounded, and the control end of the triode is configured to receive a control signal.
[0014] The present application also provides an electronic device, and the electronic device includes the discharge circuit as described above.
[0015] One technical solution adopted by the present application is: to provide a discharge circuit, the discharge circuit includes: a first capacitor, a first end of the first capacitor is connected to a first voltage input terminal, and a second end of the first capacitor is connected to a second voltage input terminal; a first switching transistor, a first end of the first switching transistor is connected to the first end of the first capacitor; a first resistor, a first end of the first resistor is connected to a second end of the first switching transistor, and a second end of the first resistor is connected to the second end of the first capacitor; a voltage - stabilizing diode, a cathode of the voltage - stabilizing diode is connected to the control end of the first switching transistor, and an anode of the voltage - stabilizing diode is connected to the second end of the first resistor; a control module, connected to the control end of the first switching transistor, and the control module is configured to: provide a bias voltage to the control end of the first switching transistor, or pull down the voltage of the control end of the first switching transistor. In the above - mentioned manner, when the device is operating normally, the discharge circuit is in a cut - off state, with almost no power consumption, and has no negative impact on the working efficiency and temperature of the device. Only after the device is powered off, the discharge circuit will perform constant - current discharge on the first capacitor, and the discharge current is finely adjusted by adjusting the parameters of the first resistor and the voltage - stabilizing diode, so that the discharge time has high controllable accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] To more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.
[0017] Among them:
[0018] Figure 1 is a schematic structural diagram of the first embodiment of the discharge circuit provided by the present application;
[0019] Figure 2 is a schematic structural diagram of the second embodiment of the discharge circuit provided by the present application;
[0020] Figure 3 is a schematic structural diagram of the third embodiment of the discharge circuit provided by the present application;
[0021] Figure 4 is a schematic structural diagram of an embodiment of the electronic device provided by the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. In addition, it should be noted that for the convenience of description, only the parts related to the present application rather than all the structures are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.
[0023] The terms "first", "second", etc. in the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.
[0024] References herein to "embodiments" mean that the particular features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and is not necessarily referring to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0025] Refer to Figure 1 , Figure 1 FIG. 7 is a schematic structural diagram of a first embodiment of a discharge circuit 100 provided by the present application. The discharge circuit 100 includes: a first capacitor C1, a first switching transistor Q1, a first resistor R1, a zener diode D1, and a control module 10.
[0026] Among them, a first end of the first capacitor C1 is connected to a first voltage input terminal HV+, and a second end of the first capacitor C1 is connected to a second voltage input terminal HV-; a first end of the first switching transistor Q1 is connected to the first end of the first capacitor C1; a first end of the first resistor R1 is connected to a second end of the first switching transistor Q1, and a second end of the first resistor R1 is connected to the second end of the first capacitor C1; a cathode of the zener diode D1 is connected to a control end of the first switching transistor Q1, and an anode of the zener diode D1 is connected to the second end of the first resistor R1; the control module 10 is connected to the control end of the first switching transistor Q1, and the control module 10 is configured to: provide a bias voltage to the control end of the first switching transistor Q1, or pull down the voltage of the control end of the first switching transistor Q1.
[0027] Specifically, the first capacitor C1 is an energy storage capacitor. When the discharge circuit 100 is powered normally, the control module 10 causes the signal at the control end of the first switching transistor Q1 to be pulled down to ground, and the first switching transistor Q1 is in an off state. No current flows through the first switching transistor Q1, and the high voltage on the first capacitor C1 will not be discharged. The entire circuit has almost no loss and has no impact on the working efficiency, no-load power consumption, and temperature rise of the device. When the power supply of the discharge circuit 100 is disconnected, the control module 10 causes the signal at the control end of the first switching transistor Q1 to be pulled up by the bias voltage, and the first switching transistor Q1 is in a conducting state. The zener diode D1 clamps the voltage at the control end of the first switching transistor Q1 to the zener voltage value of the zener diode D1. At the same time, due to the negative feedback effect of the first resistor R1, the first switching transistor Q1 enters the linear working region to perform constant current discharge on the first capacitor C1.
[0028] Optionally, the first switching transistor Q1 can be a MOS transistor, specifically an NMOS transistor, and its operating state is controlled by the voltage signal of the gate (i.e., the control terminal) of the NMOS transistor. When the gate voltage signal is at a high level, the NMOS transistor is in the conducting state. When the gate voltage signal is at a low level, the NMOS transistor is in the off state. In other embodiments, the first switching transistor Q1 can also be a semiconductor device such as a PMOS transistor or a triode, which will not be listed one by one here.
[0029] Specifically, the smaller the resistance value of the first resistor R1, the easier it is for the current passing through the first resistor R1 (i.e., the current at the second terminal of the first switching transistor Q1) to increase, and at the same time, a larger current is allowed to pass through the first switching transistor Q1. A small resistance value means that the voltage drop of the first resistor R1 is small, leaving a larger voltage space for the first capacitor C1 to discharge. Therefore, the discharge current will be relatively large. When the regulated voltage value of the voltage regulator diode D1 increases, it allows a higher voltage to be applied to the control terminal of the first switching transistor Q1, and the conduction degree of the first switching transistor Q1 is higher. At the same time, the higher control terminal voltage will cause the channel resistance of the first switching transistor Q1 to decrease, thereby allowing a larger current to pass through.
[0030] In one embodiment, when the parameters of the voltage regulator diode D1 are fixed, the discharge current of the first capacitor C1 can be increased by reducing the resistance value of the first resistor R1, and vice versa, the discharge current of the first capacitor C1 can be reduced. When the parameters of the first resistor R1 are fixed, the discharge current of the first capacitor C1 can be increased by increasing the regulated voltage value of the voltage regulator diode D1, and vice versa, the discharge current of the first capacitor C1 can be reduced.
[0031] It can be understood that in the above manner, when the device is operating normally, the control module 10 controls the first switching transistor Q1 to be in the cut-off state, so that the first capacitor C1 does not enter the discharge state, which is equivalent to the discharge circuit 100 being in the cut-off state, and the circuit has almost no power consumption, having no negative impact on the operating efficiency and temperature of the device. Only after the device is powered off, the control module 10 controls the first switching transistor Q1 to be in the conducting state, and the discharge circuit 100 will perform constant current discharge on the first capacitor C1, and the discharge current can be finely adjusted by adjusting the parameters of the first resistor R1 and the voltage regulator diode D1, so that the controllable accuracy of the discharge time is high.
[0032] Refer to Figure 2 and Figure 3 , Figure 2 and Figure 3 are schematic structural diagrams of the second and third embodiments of the discharge circuit 100 provided by the present application. The discharge circuit 100 includes: a first capacitor C1, a first switching transistor Q1, a first resistor R1, a voltage regulator diode D1, and a control module 10.
[0033] Among them, the first end of the first capacitor C1 is connected to the first voltage input terminal HV+, and the second end of the first capacitor C1 is connected to the second voltage input terminal HV-; the first end of the first switching transistor Q1 is connected to the first end of the first capacitor C1; the first end of the first resistor R1 is connected to the second end of the first switching transistor Q1, and the second end of the first resistor R1 is connected to the second end of the first capacitor C1; the cathode of the voltage stabilizing diode D1 is connected to the control terminal of the first switching transistor Q1, and the anode of the voltage stabilizing diode D1 is connected to the second end of the first resistor R1; the control module 10 is connected to the control terminal of the first switching transistor Q1, and the control module 10 is configured to: provide a bias voltage to the control terminal of the first switching transistor Q1, or pull down the voltage of the control terminal of the first switching transistor Q1.
[0034] Optionally, the control module 10 includes: a bias unit 11 and a pull-down unit 12. The bias unit 11 is connected to the control terminal of the first switching transistor Q1, and the bias unit 11 is configured to provide a bias voltage to the control terminal of the first switching transistor Q1; the pull-down unit 12 is connected to the control terminal of the first switching transistor Q1, and the pull-down unit 12 is configured to pull down the voltage of the control terminal of the first switching transistor Q1.
[0035] Optionally, the bias unit 11 includes: a second resistor R2. The first end of the second resistor R2 is connected to the first end of the first switching transistor Q1, and the second end of the second resistor R2 is connected to the control terminal of the first switching transistor Q1. Among them, the second end of the second resistor R2 is configured to provide a bias voltage to the control terminal of the first switching transistor Q1 to control the first switching transistor Q1 to enter the conducting state.
[0036] Optionally, the pull-down unit 12 includes: a second switching transistor Q2 and a voltage dividing module 121. The first end of the second switching transistor Q2 is connected to the control terminal of the first switching transistor Q1, and the second end of the second switching transistor Q2 is grounded; the first end of the voltage dividing module 121 is configured to receive a control signal, the second end of the voltage dividing module 121 is grounded, and the voltage dividing node of the voltage dividing module 121 is connected to the control terminal of the second switching transistor Q2.
[0037] Optionally, the second switching transistor Q2 can be a MOS transistor, specifically an NMOS transistor. The first end of the MOS transistor is connected to the control terminal of the first switching transistor Q1, the second end of the MOS transistor is grounded, and the control terminal of the MOS transistor is configured to receive a control signal.
[0038] Optionally, the second switching transistor Q2 can also be a triode (not shown in the figure). The first end of the triode is connected to the control terminal of the first switching transistor Q1, the second end of the triode is grounded, and the control terminal of the triode is configured to receive a control signal.
[0039] Optionally, the voltage dividing module 121 includes: a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is configured to receive a control signal, and the second end of the third resistor R3 is connected to the control end of the second switching transistor Q2; the first end of the fourth resistor R4 is connected to the second end of the third resistor R3, and the second end of the fourth resistor R4 is grounded.
[0040] Specifically, when the normal power supply of the discharge circuit 100 is on, the control signal is at a high level. After the voltage of the control signal is divided by the third resistor R3 and the fourth resistor R4, it is sent to the control end of the second switching transistor Q2 through the voltage dividing node, so that the second switching transistor Q2 is in the conducting state, and the voltage at the control end of the first switching transistor Q1 is pulled down to ground by the second switching transistor Q2; when the power supply of the discharge circuit 100 is disconnected, the control signal is at a low level, and the voltage at the voltage dividing node is also at a low level, so that the second switching transistor Q2 is in the cut-off state. At this time, the voltage at the control end of the first switching transistor Q1 is provided by the second end of the second resistor R2 and is pulled up to a high level, and the first capacitor C1 starts to discharge through the first switching transistor Q1.
[0041] In some alternative embodiments, as Figure 3 shown, Figure 3 the discharge circuit 100 shown and Figure 2 the main difference between the discharge circuit 100 shown is that the relevant descriptions of the diode D2 and the second capacitor C2 are added. Therefore, the diode D2 and the second capacitor C2 will be mainly described below. For other components in the discharge circuit 100, please refer to Figure 2 the relevant description of the embodiment shown, for example Figure 3 the voltage dividing module 121 in Figure 2 can refer to the description of the voltage dividing module 121 in
[0042] Optionally, the pull-down unit 12 further includes: a diode D2. The anode of the diode D2 is configured to receive a control signal, and the cathode of the diode D2 is connected to the first end of the voltage dividing module 121.
[0043] Optionally, the pull-down unit 12 further includes: a second capacitor C2. The first end of the second capacitor C2 is connected to the cathode of the diode D2, and the second end of the second capacitor C2 is grounded.
[0044] In one embodiment, the control signal can be input through the D / C (Direct Current) control pin. The control signal received by the D / C control pin can be an analog signal (such as a voltage signal) or a digital signal. For example, the D / C control pin can also be connected to modules such as the PFC (Power Factor Correction) module and the LLC resonant module to receive PWM (Pulse Width Modulation) pulse signals. The diode D2 and the second capacitor C2 can perform functions such as freewheeling, protection, and filtering on the PWM pulse signal.
[0045] Refer to Figure 4 , Figure 4 FIG. is a schematic structural diagram of an embodiment of an electronic device provided by the present application. The electronic device 1000 includes a discharge circuit 100, which is as described in the above embodiment and will not be elaborated here.
[0046] In several implementation manners provided by the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation manners described above are only illustrative. For example, the division of the modules or units is only a logical function division, and there can be other division manners in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
[0047] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0048] In addition, the functional units in each embodiment of the present application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.
[0049] The above are only the implementation manners of the present application, and do not limit the patent scope of the present application. Any equivalent structural or equivalent process transformation made by using the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.
Claims
1. A discharge circuit, characterized in that: The discharge circuit comprises: A first capacitor, wherein a first end of the first capacitor is connected to a first voltage input end, and a second end of the first capacitor is connected to a second voltage input end; A first switch tube, wherein a first end of the first switch tube is connected to a first end of the first capacitor; a first resistor, wherein a first end of the first resistor is connected to a second end of the first switch tube, and a second end of the first resistor is connected to a second end of the first capacitor; A voltage regulator tube, wherein a cathode of the voltage regulator tube is connected to the control end of the first switch tube, and an anode of the voltage regulator tube is connected to the second end of the first resistor; A control module is connected to the control end of the first switch tube, and the control module is configured to: provide a bias voltage to the control end of the first switch tube, or pull down the voltage of the control end of the first switch tube.
2. The discharge circuit according to claim 1, characterized in that: The control module comprises: A bias unit, the bias unit is connected to the control end of the first switch tube, and the bias unit is configured to provide a bias voltage to the control end of the first switch tube; A pull-down unit is connected to the control end of the first switch tube, and the pull-down unit is configured to pull down the voltage of the control end of the first switch tube.
3. The discharge circuit according to claim 2, characterized in that: The bias unit includes: a second resistor, a first end of the second resistor is connected to the first end of the first switch tube, and a second end of the second resistor is connected to the control end of the first switch tube.
4. The discharge circuit according to claim 2, characterized in that: The pull-down unit comprises: A second switch tube, wherein a first end of the second switch tube is connected to a control end of the first switch tube, and a second end of the second switch tube is grounded; A voltage divider module, wherein a first end of the voltage divider module is configured to receive a control signal, a second end of the voltage divider module is grounded, and a voltage divider node of the voltage divider module is connected to a control end of the second switch tube.
5. The discharge circuit according to claim 4, characterized in that: The voltage divider module comprises: a third resistor, wherein a first end of the third resistor is configured to receive the control signal, and a second end of the third resistor is connected to the control end of the second switch tube; A fourth resistor, wherein a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is grounded.
6. The discharge circuit according to claim 4, characterized in that: The pull-down unit further includes: a diode, an anode of the diode is configured to receive the control signal, and a cathode of the diode is connected to the first end of the voltage dividing module.
7. The discharge circuit according to claim 6, characterized in that: The pull-down unit further includes: a second capacitor, a first end of the second capacitor is connected to the cathode of the diode, and a second end of the second capacitor is grounded.
8. The discharge circuit according to claim 4, characterized in that: The second switch tube is a MOS tube, a first end of the MOS tube is connected to the control end of the first switch tube, a second end of the MOS tube is grounded, and the control end of the MOS tube is configured to receive the control signal.
9. The discharge circuit according to claim 4, characterized in that: The second switch tube is a triode, a first end of the triode is connected to the control end of the first switch tube, a second end of the triode is grounded, and the control end of the triode is configured to receive the control signal.
10. An electronic device, characterized in that: The electronic device comprises the discharge circuit as claimed in any one of claims 1 to 9.