Protection circuit of series switch tube and LED driving power supply
By designing a series switch protection circuit in the LED driver power supply, the problems of insufficient turn-on and turn-off time and short-circuit damage of the switch are solved, and effective protection of the switch is achieved.
Patent Information
- Application Number
- CN202423116985.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2034-12-17
AI Technical Summary
In existing LED driver power supplies, the turn-on and turn-off times of the switching transistors are difficult to meet the requirements, and they are easily damaged by spike currents or mis-conduction during short circuits.
A protection circuit for a series-connected switching transistor is designed, including a main control module, a level conversion module, a short-circuit self-locking protection module, and a clamping protection module. The switching transistor is turned on and off by control signals, and the self-locking protection function is triggered in abnormal conditions.
It effectively protects the switching transistor, avoids damage from peak currents during short circuits, and prevents false triggering, thus improving the reliability and safety of the switching transistor.
Smart Images
Figure CN223744951U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of LED drive power supply more specifically, relate to a protection circuit and LED drive power supply of series connection switch tube. BACKGROUND
[0002] In LED drive power supply, some drive power supply needs to enhance the drive ability, or low level passes through the circuit conversion and realizes the use high level voltage drive post stage switch tube. In these drive circuits, or for enhancing its current drive ability, or for low level realizes "conversion" high level drive. This design in some singlechip application scene, through the level output of MCU (3.3-5V), through the circuit "conversion" drive post stage 20V or so high voltage drive switch tube, realizes low level to high level drive. However, this way has the following problems:
[0003] The switch tube conduction and turn-off have certain time, and the existing mode only realizes through the simple increase of resistance in the circuit, this obviously can not meet the requirement of turn-off time in special occasions, and when the switch tube in series connection in the circuit short-circuit, often all because the spike current generated in the moderate time and damage. Meanwhile, the switch tube drive voltage in series connection in the circuit is insufficient and can lead to switch tube micro conduction, or the pulse drive voltage can misdirect the switch tube, and further produce pulse current and damage the switch tube. UTILITY MODEL CONTENTS
[0004] The utility model provides a protection circuit and LED drive power supply of series connection switch tube for solving the technical problems of prior art.
[0005] The utility model adopts the technical scheme in the technical problem is solved: construct a protection circuit of series connection switch tube, include: main control module, level conversion module, short circuit self locking protection module and clamping protection module,
[0006] The main control module is connected with the level conversion module, the short circuit self locking protection module is connected with the level conversion module, the source electrode of power switch tube and the clamping protection module respectively, the clamping protection module is connected with the level conversion module and the gate electrode of power switch tube respectively, and the drain electrode of power switch tube is connected with the output negative pole of LED drive power supply.
[0007] The main control module is used for output control signal,
[0008] The level conversion module is used for conduction or turn-off according to the control signal to control the conduction or turn-off of the power switch tube,
[0009] The short-circuit self-locking protection module is used for triggering a self-locking protection function and shutting down the power switch tube when a rear-stage circuit of the power switch tube is abnormal.
[0010] The clamping protection module is used for clamping protection of the power switch tube after the short-circuit self-locking protection module triggers the self-locking protection function.
[0011] The level conversion module comprises a first switch circuit, a second switch circuit and a third switch circuit.
[0012] An input end of the first switch circuit is connected to a driving voltage, output ends of the first switch circuit are connected to input ends of the short-circuit self-locking protection module and the clamping protection module, a control end of the first switch circuit is connected to an output end of the second switch circuit, an input end of the second switch circuit is connected to the main control module, and the third switch circuit is connected to an output end of the second switch circuit.
[0013] The first switch circuit comprises a first resistor, a second resistor, a third resistor and a first switch tube; the second switch circuit comprises a fourth resistor, a fifth resistor and a second switch tube; and the third switch circuit comprises a sixth resistor, a seventh resistor, a thirteenth resistor and a third switch tube.
[0014] A first end of the first resistor is connected to the driving voltage, a second end of the first resistor is connected to a first end of the first switch tube and a first end of the second resistor, a second end of the second resistor is connected to a second end of the third resistor and a second end of the second switch tube, a second end of the first switch tube is connected to a first end of the third resistor, a third end of the first switch tube is connected to a first end of the thirteenth resistor, the short-circuit self-locking protection module and the clamping protection module;
[0015] A first end of the fifth resistor is connected to the main control module, a second end of the fifth resistor is connected to a first end of the fourth resistor and a first end of the second switch tube, a third end of the second switch tube and a second end of the fourth resistor are grounded.
[0016] A first end of the sixth resistor is connected to a second end of the second switch tube, a second end of the second resistor and a second end of the third resistor, a second end of the sixth resistor is connected to a first end of the seventh resistor and a first end of the third switch tube, a second end of the seventh resistor and a third end of the third switch tube are grounded, and a second end of the third switch tube is connected to a second end of the thirteenth resistor.
[0017] The first switch tube, the second switch tube and the third switch tube are all MOS tubes in the protective circuit of the series switch tube.
[0018] The first end of the first switch tube is the drain of the MOS tube, the second end of the first switch tube is the gate of the MOS tube, and the third end of the first switch tube is the source of the MOS tube.
[0019] The first end of the second switch tube is the gate of the MOS tube, the second end of the second switch tube is the drain of the MOS tube, and the third end of the second switch tube is the source of the MOS tube.
[0020] The first end of the third switch tube is the gate of the MOS tube, the second end of the third switch tube is the drain of the MOS tube, and the third end of the third switch tube is the source of the MOS tube.
[0021] The short-circuit self-locking protection module comprises a current limiting circuit, a voltage dividing circuit and a self-locking protection circuit in the protective circuit of the series switch tube.
[0022] The current limiting circuit is connected in series with the power switch tube, the voltage dividing circuit is connected in parallel with the current limiting circuit, one end of the self-locking protection circuit is connected with the voltage dividing circuit, and the other end of the self-locking protection circuit is connected with the level conversion module.
[0023] The current limiting circuit comprises an eighteenth resistor in the protective circuit of the series switch tube.
[0024] The eighteenth resistor is connected in series with the power switch tube.
[0025] The first end of the tenth resistor is connected with the first end of the twelfth resistor and the self-locking protection circuit, the second end of the tenth resistor is connected with the second end of the eighteenth resistor, and the second end of the twelfth resistor is connected with the first end of the eighteenth resistor.
[0026] The self-locking protection circuit comprises a first diode, a ninth resistor, a third capacitor, a fourth capacitor, a fourth switch tube and a fifth switch tube in the protective circuit of the series switch tube.
[0027] The first end of the fourth switch tube is connected with the first end of the tenth resistor and the first end of the twelfth resistor, the second end of the fourth switch tube is connected with the first end of the fifth switch tube and the second end of the ninth resistor, the third end of the fourth switch tube is grounded, and the fourth capacitor is connected between the first end and the third end of the fourth switch tube.
[0028] The first end of the ninth resistor is connected to the cathode of the first diode, the anode of the first diode is connected to the level conversion module, the second end of the fifth switch tube is connected to the cathode of the first diode and the first end of the fourth resistor, the third end of the fifth switch tube is connected to the first end of the fourth switch tube, and the third capacitor is connected between the first end and the second end of the fifth switch tube.
[0029] In the protection circuit of the series switch tube, the clamping protection module comprises: a first clamping circuit and a second clamping circuit.
[0030] The input end of the first clamping circuit is connected to the level conversion module, the output end of the first clamping circuit is connected to the gate of the power switch tube, the input end of the second clamping circuit is connected to the output end of the first clamping circuit, and the output end of the second clamping circuit is connected to the source of the power switch tube.
[0031] In the protection circuit of the series switch tube, the first clamping circuit comprises: a first stabilizing tube and a second diode, and the second clamping circuit comprises: a second stabilizing tube.
[0032] The cathode of the first stabilizing tube is connected to the level conversion module, the anode of the first stabilizing tube is connected to the anode of the second diode, the cathode of the second diode is connected to the gate of the power switch tube and the cathode of the second stabilizing tube, and the anode of the second stabilizing tube is connected to the source of the power switch tube.
[0033] The utility model also provides a LED drive power supply, include: above described protection circuit of series switch tube.
[0034] The protection circuit of the series switch tube and the LED drive power supply have the following beneficial effects: comprising: a main control module, a level conversion module, a short-circuit self-locking protection module and a clamping protection module; the main control module is used for outputting control signals; the level conversion module is used for turning on or turning off according to the control signals to control the conduction or turn-off of the power switch tube; the short-circuit self-locking protection module is used for triggering the self-locking protection function and turning off the power switch tube when the rear circuit of the power switch tube is abnormal; the clamping protection module is used for clamping protection of the power switch tube after the short-circuit self-locking protection module triggers the self-locking protection function. The utility model can effectively protect the switch tube in series in the circuit, avoid the damage of the switch tube caused by the sharp peak current of the circuit, and also can avoid the damage caused by the mis-conduction. BRIEF DESCRIPTION OF DRAWINGS
[0035] The utility model will be described further below in combination with the drawings and examples, and the drawings show:
[0036] Figure 1It is the principle block diagram of the protection circuit of the series switch tube provided by the utility model.
[0037] Figure 2 It is the circuit diagram of the protection circuit of the series switch tube provided by the utility model.
[0038] Figure 3 It is the circuit diagram of the protection circuit of the series switch tube provided by the utility model. DETAILED DESCRIPTION
[0039] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.
[0040] Reference Figure 1 , Figure 1 It is the principle block diagram of the protection circuit of the series switch tube provided by the utility model. Wherein, the series switch tube of the utility model refers to the power switch tube Q7 in series at the output negative pole of the LED driving power supply.
[0041] Specifically, as shown in the figure, Figure 1 The protection circuit of the series switch tube comprises a main control module 10, a level conversion module 20, a short-circuit self-locking protection module 30 and a clamping protection module 40. Wherein, the main control module 10 is connected with the level conversion module 20, the short-circuit self-locking protection module 30 is connected with the level conversion module 20, the source of the power switch tube Q7 and the clamping protection module 40 respectively, the clamping protection module 40 is connected with the level conversion module 20 and the gate of the power switch tube Q7 respectively, and the drain of the power switch tube Q7 is connected with the output negative pole of the LED driving power supply.
[0042] The main control module 10 is used for outputting a control signal; the level conversion module 20 is used for turning on or turning off according to the control signal to control the turn-on or turn-off of the power switch tube Q7; the short-circuit self-locking protection module 30 is used for triggering the self-locking protection function and turning off the power switch tube Q7 when the rear circuit of the power switch tube Q7 is abnormal; and the clamping protection module 40 is used for carrying out the clamping protection on the power switch tube Q7 after the short-circuit self-locking protection module 30 triggers the self-locking protection function.
[0043] The utility model embodiment, main control module 10 includes main control chip, wherein, the main control chip is the main control chip (that is MCU) that LED drive power has itself, the control signal that this main control chip outputs includes high level signal and low level signal, can control the on -off of level conversion module 20 through the high, low level signal that it outputs, thereby realizes the on -off control of the gate voltage of power switch tube Q7, and then controls the on -off of power switch tube Q7.
[0044] The utility model embodiment, the level conversion module 20 can be composed of switch tube, resistance, its working state is controlled by the control signal that main control chip outputs, and, the level conversion module 20 optimized the falling edge time of drive when shutting down power switch tube Q7, so that power switch tube Q7 can reduce the overlapping time of drive voltage and control signal when using in multiway parallel, effectively reduce the pulse peak that current switching produces.
[0045] Optionally, some embodiments, the level conversion module 20 includes: first switch circuit 201, second switch circuit 202 and third switch circuit 203. Wherein, the input end of first switch circuit 201 is connected drive voltage, the output end of first switch circuit 201 is connected short circuit self-locking protection module 30 and the input end of clamping protection module 40, the control end of first switch circuit 201 is connected the output end of second switch circuit 202, the input end of second switch circuit 202 is connected main control module 10, and third switch circuit 203 is connected the output end of second switch circuit 202.
[0046] Specifically, the on -off of first switch circuit 201 is controlled by second switch circuit 202, and the on -off of second switch circuit 202 is controlled by control signal, and the on -off of third switch circuit 203 is also controlled by second switch circuit 202. When control signal is high level signal, second switch circuit 202 is turned on, and then control first switch circuit 201 is turned on, at this moment, third switch circuit 203 is in cut-off state, drive voltage is transmitted to the gate of power switch tube Q7 through first switch circuit 201 and clamping protection module 40, and power switch tube Q7 is turned on, when control signal is low level signal, second switch circuit 202 is cut off, and then control first switch circuit 201 is cut off, at this moment, third switch circuit 203 is turned on, because third switch circuit 203 is turned on and discharges rapidly, thereby reducing the falling edge time of gate voltage of power switch tube Q7 when shutting down, reaches to reduce the overlapping time of drive voltage control signal in multiway parallel use, effectively reduce the pulse peak that current switching produces.
[0047] Optionally, in some embodiments, the short-circuit self-locking protection module 30 comprises: a current limiting circuit 301, a voltage dividing circuit 302 and a self-locking protection circuit 303. The current limiting circuit 301 is connected in series with the power switch tube Q7, the voltage dividing circuit 302 is connected in parallel with the current limiting circuit 301, one end of the self-locking protection circuit 303 is connected with the voltage dividing circuit 302, and the other end of the self-locking protection circuit 303 is connected with the level conversion module 20.
[0048] Specifically, when the LED driving power supply is in normal working process, if the back stage of the power switch tube Q7 occurs short circuit or continuous short circuit, a sharp current is generated, the sharp current passes through the power switch tube Q7, at this time, the current limiting circuit 301 is used for current limiting, the current on the current limiting circuit 301 continuously increases, and then a sharp voltage corresponding to a multiple of the sharp current is generated, and the sharp voltage is divided by the voltage dividing circuit 302 to trigger the self-locking protection circuit 303 to start. After the self-locking protection circuit 303 is triggered, the driving voltage passes through the self-locking protection circuit 303 to form a loop, and a self-locking state is formed after conduction. At this time, the self-locking protection circuit 303 continuously works in the case that the LED driving power supply is in continuous power or the back stage is in continuous short circuit state, continuously pulls down the driving voltage of the power switch tube Q7, so that the power switch tube Q7 continuously maintains the off state, thereby achieving the purpose of protecting the power switch tube Q7, avoiding damage of the power switch tube Q7 due to the sharp current, and also avoiding damage of the power switch tube Q7 due to mis-conduction.
[0049] Optionally, in some embodiments, the clamping protection module 40 comprises: a first clamping circuit 401 and a second clamping circuit 402. The input end of the first clamping circuit 401 is connected with the level conversion module 20, the output end of the first clamping circuit 401 is connected with the gate of the power switch tube Q7, the input end of the second clamping circuit 402 is connected with the output end of the first clamping circuit 401, and the output end of the second clamping circuit 402 is connected with the source of the power switch tube Q7. Specifically, after the self-locking circuit is triggered to conduct, the first clamping circuit 401 can make the circuit completely cut off, which can effectively prevent the power switch tube Q7 from being damaged due to mis-conduction when the power switch tube Q7 adopts a low-voltage MOS tube. Meanwhile, the second clamping circuit 402 can also perform clamping protection when the driving voltage of the power switch tube Q7 is higher than the device specification value, thereby further protecting the power switch tube Q7.
[0050] Reference Figure 2 , Figure 2 The circuit diagram of the preferred embodiment of the protection circuit of the series switch is provided in the utility model. In the circuit diagram, Figure 3 The circuit diagram of the multi-path associated control is provided in the utility model. In the circuit diagram, Figure 3 The principle of the multi-path associated control in the utility model is the same as the principle of the single-path use. The working principle of the utility model is described below only by taking the single-path use.
[0051] Specifically, as shown inFigure 2 As shown, in this embodiment, the first switching circuit 201 includes: a first resistor R1, a second resistor R2, a third resistor R3 and a first switching transistor Q1; the second switching circuit 202 includes: a fourth resistor R4, a fifth resistor R5 and a second switching transistor Q2; the third switching circuit 203 includes: a sixth resistor R6, a seventh resistor R7, a thirteenth resistor R13 and a third switching transistor Q3.
[0052] The first terminal of the first resistor R1 is connected to the drive voltage (VCC). The second terminal of the first resistor R1 is connected to the first terminal of the first switch Q1 and the first terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the second terminal of the third resistor R3 and the second terminal of the second switch Q2. The second terminal of the first switch Q1 is connected to the first terminal of the third resistor R3. The third terminal of the first switch Q1 is connected to the first terminal of the thirteenth resistor R13, the short-circuit self-locking protection module 30, and the clamping protection module 40. The first terminal of the fifth resistor R5 is connected to the main control module 10. The second terminal of the fifth resistor R5 is connected to the first terminal of the fourth resistor R4 and the first terminal of the second switch Q2. The third terminals of the second switch Q2 and the fourth resistor R4 are grounded. The first terminal of the sixth resistor R6 is connected to the second terminal of the second switch Q2, the second terminal of the second resistor R2, and the second terminal of the third resistor R3. The second terminal of the sixth resistor R6 is connected to the first terminal of the seventh resistor R7 and the first terminal of the third switch Q3. The second terminals of the seventh resistor R7 and the third terminal of the third switch Q3 are grounded. The second terminal of the third switch Q3 is connected to the second terminal of the thirteenth resistor R13.
[0053] Optionally, in this embodiment of the present invention, the first switch Q1, the second switch Q2, and the third switch Q3 are all MOSFETs. Specifically, the first terminal of the first switch Q1 is the drain of the MOSFET, the second terminal of the first switch Q1 is the gate of the MOSFET, and the third terminal of the first switch Q1 is the source of the MOSFET; the first terminal of the second switch Q2 is the gate of the MOSFET, the second terminal of the second switch Q2 is the drain of the MOSFET, and the third terminal of the second switch Q2 is the source of the MOSFET; the first terminal of the third switch Q3 is the gate of the MOSFET, the second terminal of the third switch Q3 is the drain of the MOSFET, and the third terminal of the third switch Q3 is the source of the MOSFET.
[0054] like Figure 2 As shown, in this embodiment, the current limiting circuit 301 includes an eighteenth resistor R18; the voltage divider circuit 302 includes a tenth resistor R10 and a twelfth resistor R12; the eighteenth resistor R18 is connected in series with the power switch Q7; the first end of the tenth resistor R10 is connected to the first end of the twelfth resistor R12 and the self-locking protection circuit 303, the second end of the tenth resistor R10 is connected to the second end of the eighteenth resistor R18, and the second end of the twelfth resistor R12 is connected to the first end of the eighteenth resistor R18.
[0055] like Figure 2 As shown, in this embodiment, the self-locking protection circuit 303 includes: a first diode D1, a ninth resistor R9, a third capacitor C3, a fourth capacitor C4, a fourth switch Q4, and a fifth switch Q5; the first terminal of the fourth switch Q4 is connected to the first terminal of the tenth resistor R10 and the first terminal of the twelfth resistor R12, the second terminal of the fourth switch Q4 is connected to the first terminal of the fifth switch Q5 and the second terminal of the ninth resistor R9, the third terminal of the fourth switch Q4 is grounded, and the fourth capacitor C4 is connected between the first terminal and the third terminal of the fourth switch Q4; the first terminal of the ninth resistor R9 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the level conversion module 20 (i.e., connected to the third terminal of the first switch Q1), the second terminal of the fifth switch Q5 is connected to the cathode of the first diode D1 and the first terminal of the fourth resistor R4, the third terminal of the fifth switch Q5 is connected to the first terminal of the fourth switch Q4, and the third capacitor C3 is connected between the first terminal and the second terminal of the fifth switch Q5.
[0056] like Figure 2 As shown, in this embodiment, the first clamping circuit 401 includes: a first Zener diode ZD1 and a second diode D2; the second clamping circuit 402 includes: a second Zener diode ZD2; the cathode of the first Zener diode ZD1 is connected to the level conversion module 20 (i.e., connected to the third terminal of the first switching transistor Q1), the anode of the first Zener diode ZD1 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to the gate of the power switching transistor Q7 and the cathode of the second Zener diode ZD2, and the anode of the second Zener diode ZD2 is connected to the source of the power switching transistor Q7.
[0057] like Figure 2 As shown, when used alone (i.e., when using single-channel control), pin 1 of MCU is the control signal output by the main control chip, and VCC is the drive voltage required by the backend. Figure 2 In the circuit, when MCU1 is high, the second switch Q2 is turned on, which in turn turns on the first switch Q1. At the same time, when the second switch Q2 is turned on, it pulls down the gate level of the third switch Q3, causing the third switch Q3 to be turned off. VCC passes through the first resistor R1, the first switch Q1, the first Zener diode ZD1, and the second diode D2 to the gate of the power switch Q7. At this time, the gate of the power switch Q7 is high, and the power switch Q7 is turned on. When MCU1 is low, the source and drain of the second switch Q2 and the first switch Q1 are turned off, and the power switch Q7 is turned off. At the same time, the gate of the third switch Q3 is divided by the second resistor R2, the sixth resistor R6, and the seventh resistor R7, which turns on the source and drain of the third switch Q3. At this time, it discharges quickly through the thirteenth resistor R13 in series, thereby reducing the falling edge time of the gate voltage when the power switch Q7 is turned off.
[0058] When the circuit is in normal operation, a short circuit or a continuous short circuit occurs in the rear stage of the power switch tube Q7, a sharp current is generated through the power switch tube Q7, at this time, the current through the eighteenth resistor R18 in the circuit is increased, a sharp voltage corresponding to the multiple of the sharp current is generated by U=IR, at this time, the sharp voltage is divided by the twelfth resistor R12 and the tenth resistor R10, a series voltage division is obtained, the fourth switch tube Q4 is turned on, the fifth switch tube Q5 is turned on after the fourth switch tube Q4 is turned on, a state that the first diode D1 and the fourth switch tube Q4 are continuously turned on is formed, and then the gate voltage of the power switch tube Q7 is continuously pulled down, the power switch tube Q7 is turned off, after the self-locking protection circuit 303 is triggered, VCC forms a loop through the first resistor R1, the first switch tube Q1, the first diode D1 and the fourth switch tube Q4, and the first resistor R1 is used as a load at this time. In the case that the LED driving power supply is continuously powered, the self-locking protection circuit 303 will continuously work and continuously turn off the power switch tube Q7. When power is off and restarted or a restart control signal is given by the MCU, the circuit can recover to the normal working state.
[0059] In the utility model embodiment, the trigger point of the self-locking protection circuit 303 can be set within the device current specification value of the power switch tube Q7 by setting the reasonable parameters of the tenth resistor R10, the eighteenth resistor R18 and the twelfth resistor R12, so that the circuit can quickly respond to turn off the power switch tube Q7, and the protection effect is achieved. Meanwhile, the reasonable value of the fourth capacitor C4 can also prevent the interference signal from triggering the short circuit protection. Figure 3 The same is true when multiple circuits are used in parallel.
[0060] After the self-locking protection circuit 303 is triggered, Figure 2 In the utility model embodiment, VCC passes through the first resistor R1, the first switch tube Q1, the first diode D1, the fourth switch tube Q4 and the ground, at this time, the first resistor R1 is a false load, and there is a certain voltage drop between the first diode D1 and the fourth switch tube Q4 and the ground, at this time, the driving voltage of the power switch tube Q7 is clamped within a certain value by the first zener ZD1, so that the circuit is completely cut off, and the power switch tube Q7 is prevented from being mistakenly turned on and damaged when a low-voltage MOS tube is used. Meanwhile, the second zener ZD2 can also clamp the driving voltage of the power switch tube Q7 when the driving voltage is higher than the device specification value, so as to avoid damage to the power switch tube Q7.
[0061] The utility model also discloses an LED driving power supply, wherein the LED driving power supply can comprise the protection circuit of the series switch tube disclosed by the utility model.
[0062] The utility model discloses can realize level conversion and shutdown time optimization, short circuit protection self -locking, the clamping protection of under -drive voltage or overdrive voltage, effective protection power switch tube Q7.
[0063] The above examples are only for illustrating the technical concept and characteristics of the utility model, and the purpose is to enable the person skilled in the art to understand the content of the utility model and implement it accordingly, and cannot limit the protection scope of the utility model. Any equivalent change and modification within the scope of the utility model claim shall belong to the scope of the utility model claim.
Claims
1. A protection circuit for series connected switching tubes, characterized in that The application relates to a LED driving power supply, which comprises a main control module, a level conversion module, a short-circuit self-locking protection module and a clamping protection module. The main control module is connected with the level conversion module, the short-circuit self-locking protection module is connected with the level conversion module, the source of a power switch tube and the clamping protection module respectively, the clamping protection module is connected with the level conversion module and the gate of the power switch tube respectively, and the drain of the power switch tube is connected with the output negative pole of the LED driving power supply. The main control module is used for outputting a control signal. The level conversion module is used for turning on or turning off according to the control signal to control the on or off of the power switch tube. The short-circuit self-locking protection module is used for triggering a self-locking protection function and turning off the power switch tube when the post-stage circuit of the power switch tube is abnormal. The clamping protection module is used for clamping and protecting the power switch tube after the short-circuit self-locking protection module triggers the self-locking protection function. The level conversion module comprises a first switch circuit, a second switch circuit and a third switch circuit.
2. The protection circuit for series connected switching tubes as defined in claim 1, characterized in that The input end of the first switch circuit is connected with a driving voltage, the output end of the first switch circuit is connected with the input end of the short-circuit self-locking protection module and the clamping protection module, the control end of the first switch circuit is connected with the output end of the second switch circuit, the input end of the second switch circuit is connected with the main control module, and the third switch circuit is connected with the output end of the second switch circuit. The first switch circuit comprises a first resistor, a second resistor, a third resistor and a first switch tube, the second switch circuit comprises a fourth resistor, a fifth resistor and a second switch tube, and the third switch circuit comprises a sixth resistor, a seventh resistor, a thirteenth resistor and a third switch tube.
3. The protection circuit for series connected switching tubes as defined in claim 2, characterized in that The first end of the first resistor is connected with the driving voltage, the second end of the first resistor is connected with the first end of the first switch tube and the first end of the second resistor, the second end of the second resistor is connected with the second end of the third resistor and the second end of the second switch tube, the second end of the first switch tube is connected with the first end of the third resistor, the third end of the first switch tube is connected with the first end of the thirteenth resistor, the short-circuit self-locking protection module and the clamping protection module; The first end of the fifth resistor is connected with the main control module, the second end of the fifth resistor is connected with the first end of the fourth resistor and the first end of the second switch tube, the third end of the second switch tube and the second end of the fourth resistor are grounded; The first end of the sixth resistor is connected with the second end of the second switch tube, the second end of the second resistor and the second end of the third resistor, the second end of the sixth resistor is connected with the first end of the seventh resistor and the first end of the third switch tube, the second end of the seventh resistor and the third end of the third switch tube are grounded, and the second end of the third switch tube is connected with the second end of the thirteenth resistor. The first switch tube, the second switch tube and the third switch tube are all MOS tubes.
4. The protection circuit for series connected switching tubes as defined in claim 3, characterized in that The first end of the first switch tube is the drain of the MOS tube, the second end of the first switch tube is the gate of the MOS tube, and the third end of the first switch tube is the source of the MOS tube; The first end of the second switch tube is the gate of the MOS tube, the second end of the second switch tube is the drain of the MOS tube, and the third end of the second switch tube is the source of the MOS tube; The first end of the third switch tube is the gate of the MOS tube, the second end of the third switch tube is the drain of the MOS tube, and the third end of the third switch tube is the source of the MOS tube.
5. The protection circuit for series connected switching tubes as defined in claim 3, characterized in that The short-circuit self-locking protection module comprises a current limiting circuit, a voltage dividing circuit and a self-locking protection circuit; The current limiting circuit is connected in series with the power switch tube, the voltage dividing circuit is connected in parallel with the current limiting circuit, one end of the self-locking protection circuit is connected with the voltage dividing circuit, and the other end of the self-locking protection circuit is connected with the level conversion module.
6. The protection circuit for series connected switching tubes as defined in claim 5, characterized in that The current limiting circuit comprises an eighteenth resistor, and the voltage dividing circuit comprises a tenth resistor and a twelfth resistor; The eighteenth resistor is connected in series with the power switch tube; The first end of the tenth resistor is connected with the first end of the twelfth resistor and the self-locking protection circuit, the second end of the tenth resistor is connected with the second end of the eighteenth resistor, and the second end of the twelfth resistor is connected with the first end of the eighteenth resistor.
7. The protection circuit for series connected switching tubes as defined in claim 6, characterized in that The self-locking protection circuit comprises a first diode, a ninth resistor, a third capacitor, a fourth capacitor, a fourth switch tube and a fifth switch tube; The first end of the fourth switch tube is connected with the first end of the tenth resistor and the first end of the twelfth resistor, the second end of the fourth switch tube is connected with the first end of the fifth switch tube and the second end of the ninth resistor, the third end of the fourth switch tube is grounded, and the fourth capacitor is connected between the first end and the third end of the fourth switch tube; The first end of the ninth resistor is connected with the cathode of the first diode, the anode of the first diode is connected with the level conversion module, the second end of the fifth switch tube is connected with the cathode of the first diode and the first end of the fourth resistor, the third end of the fifth switch tube is connected with the first end of the fourth switch tube, and the third capacitor is connected between the first end and the second end of the fifth switch tube.
8. The protection circuit for series connected switching tubes as defined in claim 1, characterized in that The clamping protection module comprises a first clamping circuit and a second clamping circuit; The input end of the first clamping circuit is connected with the level conversion module, the output end of the first clamping circuit is connected with the gate of the power switch tube, the input end of the second clamping circuit is connected with the output end of the first clamping circuit, and the output end of the second clamping circuit is connected with the source of the power switch tube.
9. The protection circuit for series connected switching tubes according to claim 8, characterized in that, The first clamping circuit comprises a first stabilizing tube and a second diode, and the second clamping circuit comprises a second stabilizing tube; The cathode of the first stabilizing tube is connected with the level conversion module, the anode of the first stabilizing tube is connected with the anode of the second diode, the cathode of the second diode is connected with the gate of the power switch tube and the cathode of the second stabilizing tube, and the anode of the second stabilizing tube is connected with the source of the power switch tube.
10. An LED driving power supply, characterized by, It comprises: A protection circuit for a series switch tube according to any one of claims 1-9.