CN213693461U - Overcurrent protection circuit for low-voltage large-current DC-DC power supply input - Google Patents
Overcurrent protection circuit for low-voltage large-current DC-DC power supply input Download PDFInfo
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- CN213693461U CN213693461U CN202022699261.0U CN202022699261U CN213693461U CN 213693461 U CN213693461 U CN 213693461U CN 202022699261 U CN202022699261 U CN 202022699261U CN 213693461 U CN213693461 U CN 213693461U
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Abstract
The utility model discloses a be used for low-voltage heavy current DC-DC power input overcurrent protection circuit, belong to DC-DC power field, solved the insecurity problem of heavy current detection, its technical scheme main points are including drive circuit, drive circuit has voltage source end, control end and output, the control end is connected with sampling module, and sampling module's output is connected with voltage shaping amplifier circuit and output control circuit; the sampling module samples current and outputs a weak voltage signal according to the control end, the voltage shaping amplifying circuit receives the weak voltage signal and amplifies the signal and outputs the amplified signal to the output control circuit, and the output control circuit controls whether the output end of the driving circuit is grounded according to the amplified signal, so that the effects of improving the current detection reliability and the working reliability are achieved.
Description
Technical Field
The utility model relates to a DC-DC power field especially relates to a be used for low pressure heavy current DC-DC power input overcurrent protection circuit.
Background
Generally speaking, the DC-DC power module with low voltage and large current needs to detect the current to avoid the current from being too large, but the general overcurrent protection circuit has a complex structure, more components and parts and larger power consumption, and can occupy more power supply electric energy, so that the working efficiency of the power supply can be greatly reduced, and the temperature is easily increased due to the larger power consumption of the components and parts, thereby affecting the reliability.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to prior art's weak point, solve the technical problem in the correlation technique to a certain extent at least, provide one kind and be used for low pressure heavy current DC-DC power input overcurrent protection circuit to reach the purpose of simplifying circuit structure, improvement operational reliability and security.
In order to solve the technical problem, the technical scheme of the utility model is that: the input overcurrent protection circuit for the low-voltage large-current DC-DC power supply comprises a driving circuit, wherein the driving circuit is provided with a voltage source end, a control end and an output end, the control end is connected with a sampling module, and the output end of the sampling module is connected with a voltage shaping amplifying circuit and an output control circuit; the sampling module samples current and outputs a weak voltage signal according to the control end, the voltage shaping amplifying circuit receives the weak voltage signal, amplifies the signal and outputs the amplified signal to the output control circuit, and the output control circuit controls whether the output end of the driving circuit is grounded according to the amplified signal.
As a specific aspect of the present invention, it may be preferable that: the sampling module comprises an inductor L1, an NMOS tube Q1 and a resistor R1, wherein one end of the inductor L1 is connected with a voltage source VCC, the other end of the inductor L1 is connected with a drain electrode of the NMOS tube Q1, a grid electrode of the NMOS tube Q1 serves as an input end, and a source electrode of the NMOS tube Q1 is connected with one end of the resistor R1 and serves as an output end.
As a specific aspect of the present invention, it may be preferable that: the voltage shaping amplifying circuit comprises a comparator U1, a resistor R3, a resistor R4 and two resistance-capacitance filters, the output end of the sampling module is connected with the in-phase end of a comparison amplifier U1 through one resistance-capacitance filter, the reverse end of the comparison amplifier U1 is grounded through a resistor R3 and is connected to the output end of the comparison amplifier U1 through R4, and the output end of the comparison amplifier U1 is output to the output control circuit through the second resistance-capacitance filter.
As a specific aspect of the present invention, it may be preferable that: the output control circuit is an NPN triode Q2, the base electrode of the NPN triode Q2 is connected with the output of the voltage shaping amplifying circuit, the emitting electrode of the NPN triode Q2 is grounded, and the collecting electrode of the NPN triode Q2 is connected with the driving circuit.
As a specific aspect of the present invention, it may be preferable that: the driving circuit is a 51 single chip microcomputer or an LM1575 or LM1117 chip.
The utility model discloses technical effect mainly embodies in following aspect: current is collected through the mode of little resistance sampling to amplify the voltage signal who will be weak and handle, thereby realize the improvement of the feedback of signal and driving force, make to the detection and the control of current safe and reliable more, reduce the harm of heavy current and the insecurity that detects, improve reliability and the security of work.
Drawings
FIG. 1 is a schematic circuit diagram of an embodiment.
Reference numerals: 1. a drive circuit; 11. a voltage source terminal; 12. a control end; 13. an output terminal of the drive circuit; 2. a sampling module; 3. a voltage shaping amplifying circuit; 31. a resistance-capacitance filter; 4. and an output control circuit.
Detailed Description
The embodiments of the present invention will be described in detail below, examples of which are illustrated in the accompanying drawings, and the embodiments described below by referring to the drawings are exemplary and intended to explain the present invention so that the technical solutions of the present invention can be more easily understood and grasped, and cannot be construed as limiting the present invention.
Example (b):
a low-voltage large-current DC-DC power supply input overcurrent protection circuit is disclosed, referring to fig. 1, and comprises a drive circuit 1, wherein the drive circuit 1 is provided with a voltage source end 11, a control end 12 and an output end 13 of the drive circuit, the control end 12 is connected with a sampling module 2, and the output end of the sampling module 2 is connected with a voltage shaping amplifying circuit 3 and an output control circuit 4; the sampling module 2 samples current and outputs a weak voltage signal according to the control end 12, the voltage shaping amplifying circuit 3 receives the weak voltage signal and amplifies the signal and outputs the amplified signal to the output control circuit 4, and the output control circuit 4 controls whether the output end 13 of the driving circuit is grounded according to the amplified signal.
Specifically, the sampling module 2 includes an inductor L1, an NMOS transistor Q1, and a resistor R1, one end of the inductor L1 is connected to the voltage source VCC, the other end of the inductor L1 is connected to the drain of the NMOS transistor Q1, the gate of the NMOS transistor Q1 is used as an input end, and the source of the NMOS transistor Q1 is connected to one end of the resistor R1 and is used as an output end.
The voltage shaping amplifying circuit 3 comprises a comparator U1, a resistor R3, a resistor R4 and two RC filters 31, the output end of the sampling module 2 is connected with the in-phase end of a comparison amplifier U1 through one RC filter 31, the reverse end of the comparison amplifier U1 is grounded through a resistor R3 and is connected with the output end of the comparison amplifier U1 through R4, and the output end of the comparison amplifier U1 is output to the output control circuit 4 through the second RC filter 31. A rc filter 31 includes a resistor R2 and a capacitor C1. The second rc filter 31 comprises a resistor R5 and a capacitor C2. The rc filter 31 has one end of a resistor as an input end, the other end of the resistor connected to one end of the capacitor C2 as an output end, and the other end of the capacitor C2 grounded.
The output control circuit 4 is an NPN triode Q2, the base of the NPN triode Q2 is connected to the output of the voltage shaping amplifying circuit 3, the emitter of the NPN triode Q2 is grounded, and the collector of the NPN triode Q2 is connected to the driving circuit 1.
The driving circuit 1 is a 51-chip microcomputer or an LM1575 or LM1117 chip.
When the circuit structure works, firstly, the inductor L1 collects a large current, namely, the large current of the voltage source VCC, and the inductor L1 obstructs the action of direct current, so that the large current sampling is smoothly carried out. The current sampling range of the scheme is 2-5A. The NMOS transistor Q1 is controlled by the driving circuit 1, when the driving circuit 1 outputs a high level, the NMOS transistor Q1 is turned on, so that a sampling voltage is formed on the resistor R1, the resistor R1 is a small resistor, generally a 0.1-1 ohm resistor is adopted, so that a weak voltage is formed, the weak voltage is a voltage of 0.5-5V, and in order to improve the transmission reliability of a voltage signal and improve the driving capability, the voltage signal can be amplified by using the rc filter 31 and the comparison amplifier U1, so that the NPN triode Q2 can be effectively driven, so that when the current is too large, the NPN triode Q2 is turned on, and at this time, the output end 13 of the driving circuit can be reliably grounded. The circuit can be introduced into the existing driving circuit 1, and the driving circuit 1 is a 51 single chip microcomputer or an LM1575 or LM1117 chip, which are examples of applications.
Of course, the above is only a typical example of the present invention, and besides, the present invention can also have other various specific embodiments, and all technical solutions adopting equivalent replacement or equivalent transformation are all within the scope of the present invention as claimed.
Claims (5)
1. The input overcurrent protection circuit for the low-voltage large-current DC-DC power supply comprises a driving circuit, wherein the driving circuit is provided with a voltage source end, a control end and an output end, and is characterized in that the control end is connected with a sampling module, and the output end of the sampling module is connected with a voltage shaping amplifying circuit and an output control circuit; the sampling module samples current and outputs a weak voltage signal according to the control end, the voltage shaping amplifying circuit receives the weak voltage signal, amplifies the signal and outputs the amplified signal to the output control circuit, and the output control circuit controls whether the output end of the driving circuit is grounded according to the amplified signal.
2. The input overcurrent protection circuit for a low-voltage high-current DC-DC power supply of claim 1, wherein: the sampling module comprises an inductor L1, an NMOS tube Q1 and a resistor R1, wherein one end of the inductor L1 is connected with a voltage source VCC, the other end of the inductor L1 is connected with a drain electrode of the NMOS tube Q1, a grid electrode of the NMOS tube Q1 serves as an input end, and a source electrode of the NMOS tube Q1 is connected with one end of the resistor R1 and serves as an output end.
3. A low voltage high current DC-DC power input overcurrent protection circuit as set forth in claim 2, wherein: the voltage shaping amplifying circuit comprises a comparator U1, a resistor R3, a resistor R4 and two resistance-capacitance filters, the output end of the sampling module is connected with the in-phase end of a comparison amplifier U1 through one resistance-capacitance filter, the reverse end of the comparison amplifier U1 is grounded through a resistor R3 and is connected to the output end of the comparison amplifier U1 through R4, and the output end of the comparison amplifier U1 is output to the output control circuit through the second resistance-capacitance filter.
4. A low voltage high current DC-DC power input overcurrent protection circuit as set forth in claim 3, wherein: the output control circuit is an NPN triode Q2, the base electrode of the NPN triode Q2 is connected with the output of the voltage shaping amplifying circuit, the emitting electrode of the NPN triode Q2 is grounded, and the collecting electrode of the NPN triode Q2 is connected with the driving circuit.
5. A low voltage high current DC-DC power input overcurrent protection circuit as set forth in claim 2, wherein: the driving circuit is a 51 single chip microcomputer or an LM1575 or LM1117 chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022699261.0U CN213693461U (en) | 2020-11-19 | 2020-11-19 | Overcurrent protection circuit for low-voltage large-current DC-DC power supply input |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022699261.0U CN213693461U (en) | 2020-11-19 | 2020-11-19 | Overcurrent protection circuit for low-voltage large-current DC-DC power supply input |
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| Publication Number | Publication Date |
|---|---|
| CN213693461U true CN213693461U (en) | 2021-07-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022699261.0U Active CN213693461U (en) | 2020-11-19 | 2020-11-19 | Overcurrent protection circuit for low-voltage large-current DC-DC power supply input |
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| Country | Link |
|---|---|
| CN (1) | CN213693461U (en) |
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- 2020-11-19 CN CN202022699261.0U patent/CN213693461U/en active Active
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