CN219498943U - Low side switch protection circuit - Google Patents
Low side switch protection circuit Download PDFInfo
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- CN219498943U CN219498943U CN202221458912.XU CN202221458912U CN219498943U CN 219498943 U CN219498943 U CN 219498943U CN 202221458912 U CN202221458912 U CN 202221458912U CN 219498943 U CN219498943 U CN 219498943U
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Abstract
The utility model is applicable to the technical field of integrated circuits, and provides a low-side switch protection circuit, which comprises: the power supply unit comprises VCC, GND and VDD, wherein VCC in the circuit is the positive electrode of the circuit power supply, GND is the negative electrode of the circuit, and VDD is the positive electrode of the circuit load; the logic unit is used for switching on and off the power switch device and the load; the current limiting unit is used for limiting current change caused by a load and preventing and protecting the power switch device; the power switch unit is used for controlling the opening and closing of the load; the starting unit is used for providing the starting voltage coupled with the input signal for the switching device, the power switching device and the load so as to realize starting, and the starting unit has the beneficial effects that: protection of the power switching device can be achieved in the event of overload and disconnection.
Description
Technical Field
The utility model belongs to the technical field of integrated circuits, and particularly relates to a low-side switch protection circuit.
Background
At present, many applications in modern automotive electronic circuits use high-side and low-side switches as driving outputs, and the driving outputs are operated in complex automotive electronic and electric systems, so that output overload or short circuit conditions are extremely easy to occur, and the automotive electronic and electric systems generate irreversible operation failure.
The low-side electronic switch circuits commonly used at present have the following components: the first is various special electronic switch driving chips with temperature protection and current detection, when an external load is short-circuited, the temperature of the chip begins to rise, the driving is automatically disconnected when the temperature is high to a certain degree, and the chip is automatically started when the chip is cooled down, so that the chip is repeatedly started until the chip is circulated for a certain number of times, and the chip is invalid; if the chip has fault output or a diagnosis circuit is externally added, the output can be turned off after the fault occurs so as to protect the chip; the chip has higher cost, and the chip cannot achieve higher current detection precision in places needing higher current detection such as soft short circuit and the like; the second is to connect a resistor with smaller resistance value in series on the electronic switch, and the microprocessor detects the voltage on the resistor so as to judge the state of the load; when the load is short-circuited to cause overcurrent, the microprocessor can turn off the electronic switch to protect the switch, but when the load is hard-shorted, the delay from the detection of the current by the microprocessor to the turn-off of the switch can be damage or direct damage to the electronic switch.
Disclosure of Invention
The embodiment of the utility model aims to provide a low-side switch protection circuit, which aims to solve the problems in the prior art determined in the background art.
The embodiment of the utility model is realized in such a way that a low-side switch protection circuit comprises: the power supply unit comprises VCC, GND and VDD, wherein VCC in the circuit is the positive electrode of the circuit power supply, GND is the negative electrode of the circuit, and VDD is the positive electrode of the circuit load;
the logic unit is used for switching on and off the power switch device and the load;
the current limiting unit is used for limiting current change caused by a load and preventing and protecting the power switch device;
the power switch unit is used for controlling the opening and closing of the load;
and the starting unit is used for providing the starting voltage coupled with the input signal to the switching device, the power switching device and the load so as to realize starting.
Preferably, the starting unit comprises a signal coupling starting circuit, the signal coupling starting circuit comprises a resistor R5, a resistor R2, a resistor R3, a resistor R10, a resistor R7, a resistor R1, a resistor R6, a triode Q1, a triode Q2, a coupling capacitor C1 and a field effect transistor Q3, one end of the resistor R5 is connected with a signal input, the other end of the resistor R5 is connected with a base electrode of the triode Q2 in series, one end of the resistor R2 is connected with a power VCC, the other end of the resistor R2 is connected with the base electrode of the triode Q2 in series, one end of the resistor R3 is connected with a power VCC, the other end of the resistor R3 is connected with an emitter of the triode Q2 in series, the coupling capacitor C1 is connected with a collector electrode of the triode Q2 in series, a base electrode of the triode Q4 in series, the resistor R10 is connected with a base electrode of the triode Q4 in parallel, one end of the resistor R7 is connected with a base electrode of the triode Q1 in series, the other end of the resistor R1 is connected with a base electrode of the triode Q1 in series, and the resistor R6 is connected with a collector electrode of the triode Q3 in series.
Preferably, the logic unit includes a resistor R5, a resistor R2, a resistor R3, a triode Q2, a resistor R9, a resistor R15, a resistor R16, a resistor R11, a triode Q7, a triode Q6 and a field effect transistor Q3, wherein one end of the resistor R5 is connected with a signal input, the other end is connected with a base electrode of the triode Q2 in series, one end of the resistor R2 is connected with a power VCC, the other end is connected with a base electrode of the triode Q2 in series, one end of the resistor R3 is connected with a power VCC, the other end is connected with an emitter electrode of the triode Q2 in series, the resistor R9 is connected with a collector electrode of the triode Q2 in series, the resistor R15 is connected with a base electrode and an emitter electrode of the triode Q7 in parallel, one end of the resistor R11 is connected with a power VCC, the other end is connected with a base electrode of the triode Q6 in series, the resistor R16 is connected with a base electrode and an emitter electrode of the triode Q6 in parallel, and a collector electrode of the triode Q6 is connected with a grid electrode of the field effect transistor Q3.
Preferably, the current limiting unit includes a resistor R12, a resistor R13, a resistor R14, a resistor R8, a capacitor C2, and a triode Q5, where the resistor R12, the resistor R13, and the resistor R14 are connected in parallel, and one common end of the resistor R12, the resistor R13, and the resistor R14 is connected in parallel to GND, the other common end is connected to the source of the fet Q3, and the R8, C2 are connected in parallel to the gate and the source of the fet Q3, and the base and the collector of the triode Q5 are connected to the source and the gate of the fet Q3, respectively.
Preferably, the power switch unit comprises a resistor R4, a resistor R6, a resistor R1, a resistor R12, a resistor R13, a resistor R14, a triode Q1 and a field effect transistor Q3, wherein one end of the resistor R4 is connected with a base electrode of the triode Q1, the other end of the resistor R4 is connected with a negative electrode of a load and a drain electrode of the field effect transistor, the resistor R1 is connected with an emitter electrode and the base electrode of the triode Q1 in parallel, one end of the resistor R6 is connected with a collector electrode of the triode Q1, the other end of the resistor R6 is connected with a grid electrode of the field effect transistor, the resistor R12, the resistor R13 and the resistor R14 are commonly connected with GND, and the other end of the resistor R14 is commonly connected with a source electrode of the field effect transistor.
According to the low-side switch protection circuit provided by the embodiment of the utility model, when a load is overloaded for a certain reason, voltage drops at two ends of the resistors R12, R13 and R14 rise, when the voltage reaches the threshold voltage of the base electrode of the triode Q5, the conduction time of the triode Q5 is prolonged, the cut-off time is shortened, the conduction time of the field effect tube Q3 is shortened, the cut-off time is prolonged, the current is constant in a cycle, and the power switch device is protected in the moment of power on; when a load is short-circuited due to a certain reason, the VDD voltage is applied to the triode Q1 through the load and the resistor R4, so that the Q1 is reversely biased to cut off, the VCC voltage cannot be added to the grid electrode of the field effect transistor Q3 due to the cut-off of the triode Q1, the Q3 is cut off, and the VDD voltage cannot form a loop due to the cut-off of the Q3, so that the power switch device is protected.
Drawings
Fig. 1 is a connection structure diagram of a low-side switch protection circuit according to an embodiment of the present utility model;
Detailed Description
The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.
Specific implementations of the utility model are described in detail below in connection with specific embodiments.
Referring to fig. 1, a block diagram of a low-side switch protection circuit according to an embodiment of the present utility model is shown, and a power supply unit includes VCC, GND and VDD, where VCC is an anode of a power supply of the circuit, GND is a cathode of the circuit, and VDD is an anode of a load of the circuit;
the logic unit is used for switching on and off the power switch device and the load;
the current limiting unit is used for limiting current change caused by a load and preventing and protecting the power switch device;
the power switch unit is used for controlling the opening and closing of the load;
and the starting unit is used for providing the starting voltage coupled with the input signal to the switching device, the power switching device and the load so as to realize starting.
As shown in fig. 1, as a preferred embodiment of the present utility model, the starting unit includes a signal coupling starting circuit, the signal coupling starting circuit includes a resistor R5, a resistor R2, a resistor R3, a resistor R10, a resistor R7, a resistor R1, a resistor R6, a transistor Q1, a transistor Q2, a coupling capacitor C1, and a field effect transistor Q3, one end of the resistor R5 is connected to a signal input, the other end is connected in series with a base of the transistor Q2, one end of the resistor R2 is connected to a power VCC, the other end is connected in series with an emitter of the transistor Q2, the coupling capacitor C1 is connected in series with a collector of the transistor Q2, a base of the transistor Q4, a resistor R10 is connected in parallel with the base of the transistor Q4, the resistor R7 is connected in series with a collector of the transistor Q4, one end of the resistor R1 is connected to the power supply, the other end is connected with a base of the transistor Q1, the resistor R6 is connected in series with a gate of the transistor Q1, when a switching signal input is connected in series with the base of the transistor Q2, the VCC is connected to the power supply, the other end is connected to the drain of the transistor Q3, and the Q4 is connected to the drain of the transistor Q4 via the resistor Q4, and the Q1 is connected to the drain of the resistor Q4, and the Q4 is connected to the power supply.
As shown in fig. 1, as another preferred embodiment of the present utility model, the logic unit includes a resistor R5, a resistor R2, a resistor R3, a triode Q2, a resistor R9, a resistor R15, a resistor R16, a resistor R11, a triode Q7, a triode Q6, and a field effect transistor Q3, wherein one end of the resistor R5 is connected to a signal input, the other end is connected in series with a base of the triode Q2, one end of the resistor R2 is connected to a power VCC, the other end is connected in series with the base of the triode Q2, one end of the resistor R3 is connected to a power VCC, the other end is connected in series with an emitter of the triode Q2, the resistor R9 is connected in parallel with a base and an emitter of the triode Q7, one end of the resistor R11 is connected in series with a base of the triode Q6, the other end is connected in parallel with a base and an emitter of the triode Q6, and the collector of the triode Q6 is connected with a gate of the field effect transistor Q3.
As shown in fig. 1, as another preferred embodiment of the present utility model, the current limiting unit includes a resistor R12, a resistor R13, a resistor R14, a resistor R8, a capacitor C2, and a transistor Q5, where the resistor R12, the resistor R13, and the resistor R14 are connected in parallel, one common terminal GND of the three is connected to the source of the fet Q3, the other common terminal fet Q8 is connected in parallel to the gate and the source of the fet Q3, and the base and the collector of the transistor Q5 are connected to the source and the gate of the fet Q3, respectively.
As shown in fig. 1, as another preferred embodiment of the present utility model, the power switch unit includes a resistor R4, a resistor R6, a resistor R1, a resistor R12, a resistor R13, a resistor R14, a triode Q1, and a field effect transistor Q3, wherein one end of the resistor R4 is connected with the base of the triode Q1, the other end is connected with the negative electrode of the load and the drain electrode of the field effect transistor, the resistor R1 is connected in parallel with the emitter and the base of the triode Q1, one end of the resistor R6 is connected with the collector of the triode Q1, the other end is connected with the gate of the field effect transistor, the resistor R12, the resistor R13, and the resistor R14 are commonly connected with GND, and the other end is commonly connected with the source electrode of the field effect transistor.
In the embodiment of the utility model, a low-side switch protection circuit is provided, when a load is overloaded for some reason, the voltage drops at two ends of resistors R12, R13 and R14 rise, when the voltage reaches the threshold voltage of the base electrode of a triode Q5, the conduction time of the triode Q5 is prolonged, the cut-off time is shortened, the conduction time of a field effect tube Q3 is shortened, the cut-off time is prolonged, the current is constant by repeated circulation, and the power switch device is protected at the moment of power on;
when a load is short-circuited due to a certain reason, the VDD voltage is applied to the triode Q1 through the load and the resistor R4, so that the Q1 is reversely biased to cut off, the VCC voltage cannot be added to the grid electrode of the field effect transistor Q3 due to the cut-off of the triode Q1, the Q3 is cut off, and the VDD voltage cannot form a loop due to the cut-off of the Q3, so that the power switch device is protected.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.
Claims (5)
1. A low side switch protection circuit, comprising:
the power supply unit comprises VCC, GND and VDD, wherein VCC is the positive electrode of the circuit power supply, GND is the negative electrode of the circuit, and VDD is the positive electrode of the circuit load;
the logic unit is used for switching on and off the power switch device and the load;
the current limiting unit is used for limiting current change caused by a load and preventing and protecting the power switch device;
the power switch unit is used for controlling the opening and closing of the load;
and the starting unit is used for providing the starting voltage coupled with the input signal to the switching device, the power switching device and the load so as to realize starting.
2. The low-side switch protection circuit according to claim 1, wherein the starting unit comprises a signal coupling starting circuit, the signal coupling starting circuit comprises a resistor R5, a resistor R2, a resistor R3, a resistor R10, a resistor R7, a resistor R1, a resistor R6, a triode Q1, a triode Q2, a coupling capacitor C1 and a field effect transistor Q3, one end of the resistor R5 is connected with a signal input, the other end is connected with a base electrode of the triode Q2 in series, one end of the resistor R2 is connected with a power VCC, the other end is connected with a base electrode of the triode Q2 in series, one end of the resistor R3 is connected with a power VCC, the other end is connected with an emitter electrode of the triode Q2 in series, the coupling capacitor C1 is connected with a collector electrode of the triode Q2 in series, the resistor R10 is connected with the base electrode of the triode Q4 in parallel, the resistor R7 is connected with a collector electrode of the triode Q4 in series, one end of the resistor R1 is connected with the power VCC, the other end is connected with a base electrode of the triode Q1, and the resistor R6 is connected with a collector electrode of the field effect transistor Q3 in series.
3. The low-side switch protection circuit according to claim 2, wherein the logic unit comprises a resistor R5, a resistor R2, a resistor R3, a triode Q2, a resistor R9, a resistor R15, a resistor R16, a resistor R11, a triode Q7, a triode Q6 and a field effect transistor Q3, the resistor R9 is respectively connected with a collector of the triode Q2 and a base of the triode Q7 in series, the resistor R15 is connected with a base and an emitter of the triode Q7 in parallel, one end of the resistor R11 is connected with a power VCC, the other end is connected with a base of the triode Q6 in series, the resistor R16 is connected with the base and the emitter of the triode Q6 in parallel, and a collector of the triode Q6 is connected with a gate of the field effect transistor Q3.
4. The low-side switch protection circuit according to claim 3, wherein the current limiting unit comprises a resistor R12, a resistor R13, a resistor R14, a resistor R8, a capacitor C2, and a transistor Q5, the resistor R12, the resistor R13, and the resistor R14 are connected in parallel, one common terminal GND of the three is connected to the source of the field effect transistor Q3, the other common terminal fet Q3 is connected in parallel to the gate and the source of the field effect transistor Q3, and the base and the collector of the transistor Q5 are connected to the source and the gate of the field effect transistor Q3, respectively.
5. The low-side switch protection circuit according to claim 3, wherein the power switch unit comprises a resistor R4, a resistor R6, a resistor R1, a resistor R12, a resistor R13, a resistor R14, a triode Q1 and a field effect transistor Q3, one end of the resistor R4 is connected with a base electrode of the triode Q1, the other end is connected with a negative electrode of a load and a drain electrode of the field effect transistor, the resistor R1 is connected with an emitter and a base electrode of the triode Q1 in parallel, one end of the resistor R6 is connected with a collector electrode of the triode Q1, the other end is connected with a grid electrode of the field effect transistor, the resistor R12, the resistor R13 and the resistor R14 are commonly connected with a GND, and the other end is commonly connected with a source electrode of the field effect transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221458912.XU CN219498943U (en) | 2022-06-13 | 2022-06-13 | Low side switch protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221458912.XU CN219498943U (en) | 2022-06-13 | 2022-06-13 | Low side switch protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219498943U true CN219498943U (en) | 2023-08-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221458912.XU Active CN219498943U (en) | 2022-06-13 | 2022-06-13 | Low side switch protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219498943U (en) |
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2022
- 2022-06-13 CN CN202221458912.XU patent/CN219498943U/en active Active
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