CN202218005U - Short circuit protecting circuit and power source having short circuit protecting function - Google Patents
Short circuit protecting circuit and power source having short circuit protecting function Download PDFInfo
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- CN202218005U CN202218005U CN201120273690XU CN201120273690U CN202218005U CN 202218005 U CN202218005 U CN 202218005U CN 201120273690X U CN201120273690X U CN 201120273690XU CN 201120273690 U CN201120273690 U CN 201120273690U CN 202218005 U CN202218005 U CN 202218005U
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Abstract
The utility model relates to short circuit protecting circuits and a power source having a short circuit protecting function. The power source includes a bridge circuit adopting a field control switch tubes. Short circuit protecting circuits are arranged in corresponding to the switch tubes on at least one bridge arms. The short circuit protecting circuits includes sampling branch circuits. Sampling output terminals of the sampling branch circuits connect with determining branch circuits. Signal output terminals of the determining branch circuits connect with a driving circuit in a controlling manner. In the utility model, on resistance of the field control switch tubes themselves is adopted as detecting resistance. When flowing currents exceed a predetermined value, protection circuits act, and the switch tubes are switched off. The protection method in the utility model utilizes parasitic resistors of the power tubes themselves skillfully and reduces unnecessary loss of traditional detection resistors, thereby improving efficiency and power source reliability.
Description
Technical field
The utility model relates to the DC power supply field, and particularly a kind of short-circuit protection circuit reaches the power supply by this this circuit of protection.
Background technology
Along with development of technology, the high frequency switch power technology has become the main flow of power technology, and application is the most extensive and the electric power FET is in the middle low power field.The application of power field is very extensive: from civilian to military, from space flight to the navigation etc.Power supply how to make high reliability becomes the target of Power Engineer unremitting pursue.Short-circuit protection circuit is an important component part of power supply reliability.Traditional short-circuit protection all is that current sense resistor of serial connection is taken a sample in loop of power circuit, and when current ratio was big, the power loss of sample resistance was excessive, brings hidden danger for power supply heat sinking and reliability.
The utility model content
The purpose of the utility model provides the power supply of a kind of short-circuit protection circuit and band short-circuit protection function, for the main control chip in the power supply and other chip respective pins provide protection, and solves and adopts resistance sampling to detect electric current to bring the excessive problem of power loss.
For realizing above-mentioned purpose; A kind of scheme of the utility model is: a kind of power supply with short-circuit protection function; Comprise the bridge circuit that adopts the field ring shift switch pipe, the switching tube correspondence at least one brachium pontis is provided with short-circuit protection circuit, and said short-circuit protection circuit comprises the sampling branch road; The sampling output of sampling branch road connects a judgement branch road, judges the signal output part control connection drive circuit of branch road; Said sampling branch road comprises first terminals and second terminals that are used to be connected the field ring shift switch management and control system utmost point that are used to connect the field ring shift switch tube anode; Be provided with diode in series (D2) and first resistance (R1) between two terminals; Diode (D2) negative pole connects said first terminals; Diode (D2) is anodal to connect said second terminals, the sampling output of the just very said sampling branch road of said diode (D2) through first resistance (R1); Said judgement branch road comprises a voltage-stabiliser tube (D1), and this voltage-stabiliser tube (D1) negative pole connects the output of said sampling branch road, and it is anodal through second resistance (R2) ground connection, the signal output part of its just very said judgement branch road (OUT).
Be provided with first filter capacitor (C1) between said diode (D2) positive pole and the earth point, said second resistance (R2) is parallelly connected with second filter capacitor (C2).
Said drive circuit comprises: triode (Q1), its base stage connects said signal output part (OUT) through a current-limiting resistance (R3), its collector electrode output drive signal.
Said drive circuit also is connected with buffer circuit: buffer circuit comprises optic coupling element (U1); Between former limit series connection triode (Q1) collector electrode and power supply of optic coupling element; The secondary one end ground connection of optic coupling element (U1), the other end are used to connect the chip pin of corresponding need protection.
Said field ring shift switch pipe is electric power VMOS pipe, said switching tube anode, negative electrode, the drain electrode of the respectively corresponding electric power VMOS pipe of grid, source electrode, grid.
The another kind of scheme of the utility model is: a kind of short-circuit protection circuit, and said short-circuit protection circuit comprises the sampling branch road, the sampling output of sampling branch road connects a judgement branch road, judges the signal output part control connection drive circuit of branch road; Said sampling branch road comprises first terminals and second terminals that are used to be connected the field ring shift switch management and control system utmost point that are used to connect the field ring shift switch tube anode; Be provided with diode in series (D2) and first resistance (R1) between two terminals; Diode (D2) negative pole connects said first terminals; Diode (D2) is anodal to connect said second terminals, the sampling output of the just very said sampling branch road of said diode (D2) through first resistance (R1); Said judgement branch road comprises a voltage-stabiliser tube (D1), and this voltage-stabiliser tube (D1) negative pole connects the output of said sampling branch road, and it is anodal through second resistance (R2) ground connection, the signal output part of its just very said judgement branch road (OUT).
Be provided with first filter capacitor (C1) between said diode (D2) positive pole and the earth point, said second resistance (R2) is parallelly connected with second filter capacitor (C2).
Said drive circuit comprises: triode (Q1), its base stage connects said signal output part (OUT) through a current-limiting resistance (R3), its collector electrode output drive signal.
Said drive circuit also is connected with buffer circuit: buffer circuit comprises optic coupling element (U1); Between former limit series connection triode (Q1) collector electrode and power supply of optic coupling element; The secondary one end ground connection of optic coupling element (U1), the other end are used to connect the chip pin of corresponding need protection.
Said field ring shift switch pipe is electric power VMOS pipe, said switching tube anode, negative electrode, the drain electrode of the respectively corresponding electric power VMOS pipe of grid, source electrode, grid.
Because switching tube itself is in the loop of power circuit, so this novel conducting resistance of field ring shift switch pipe self of utilizing comes electric current is taken a sample, saved traditional power detection resistance, so promptly simplify circuit and improved circuit reliability again.Utilize the voltage control characteristic of field ring shift switch pipe, under normal condition, the conducting of switching tube or end, tube voltage drop is very little, diode D2 conducting, the low conducting voltage-stabiliser tube D2 that is not enough to of diode D2 anode voltage.Under short-circuit conditions, the electric current surge of flowing through switching tube causes tube voltage drop to increase; When reaching set point, diode D2 is blocked, and voltage-stabiliser tube D1 conducting is for drive circuit at the back provides control signal.
The control signal of output drives triode Q1, and then drives optic coupling element, and optic coupling element secondary output signal makes the chip pin ground connection that needs protection.
Description of drawings
Fig. 1 is a kind of schematic diagram of short-circuit protection circuit;
Fig. 2 is the drive circuit schematic diagram of another kind of short-circuit protection circuit;
Fig. 3 is the circuit block diagram of a kind of power supply embodiment;
Fig. 4 is the circuit block diagram of another kind of power supply embodiment.
Embodiment
Below in conjunction with accompanying drawing the utility model is done further detailed explanation.
Short-circuit protection circuit embodiment
A kind of short-circuit protection circuit is as shown in Figure 1, and this short circuit current is applied in the bridge circuit of Switching Power Supply, and electric bridge adopts the VMOS pipe.Like figure, the drain electrode of the VMOS pipe on brachium pontis is designated as D, and grid is designated as G.
This short-circuit protection circuit comprises sampling, decision circuitry and isolated drive circuit; Sampling, decision circuitry comprise diode D2; The D2 negative pole connects drain D; It is anodal through first resistance R, 1 connection grid G, and also through the series arm ground connection of a voltage-stabiliser tube D1 and second resistance R 2, it is anodal that voltage-stabiliser tube D1 negative pole connects D2 for the D2 positive pole.Voltage-stabiliser tube D1 positive pole is the signal output part OUT of sampling, decision circuitry.Capacitor C 1, C2 is used for filtering.
Signal output part OUT connects isolated drive circuit.The implementation of isolated drive circuit is more; Like Fig. 1, signal output part OUT connects triode Q1 base stage B, triode Q1 emitter E ground connection through a current-limiting resistance R3; The former limit that string is established an optic coupling element U1 between collector electrode and the supply voltage 12V; The secondary one end ground connection of optic coupling element U1, other end output protection signal promptly connects the chip pin that needs protection.When the output protection signal, protected pin can be short to ground, thus protection chip pin (perhaps operating corresponding main control chip pin level turn-offs switching tube).
When power work just often because little this moment of the D2 conducting of VMOS pipe source-drain electrode conduction voltage drop, so D1 turn-offs, the E of Q1, not conducting of general rule optocoupler U1 of the B no forward voltage drop Q1 of end; When too big as if the electric current that flows through the VMOS pipe, the source electrode of VMOS pipe and the voltage (I*RDS) between drain electrode increase, D2 shutoff when reaching set point, and the D1 conducting, the Q1 conducting finally causes the U1 conducting, and this moment, the low level guard signal was sent to the protection pin of chip.This kind protective circuit is novel and the fast reliability advantages of higher of speed arranged.
Foregoing circuit also can not adopt light-coupled isolation and adopt relay to isolate, thereby controls devices such as some indicator lights, buzzer, is used for reporting to the police or other purposes.
Execution mode as more simplifying also can only use drive circuit without buffer circuit, and like Fig. 2, guard signal is drawn from transistor collector.
Power supply embodiment
As high performance Switching Power Supply, bridge rectifier or inversion electric bridge are absolutely necessary, and triggering mode can be phasedly also can adopt the PWM mode.Switching Power Supply as shown in Figure 3, two VMOS pipes of going up brachium pontis of electric bridge are equipped with short-circuit protection circuit, and are perhaps as shown in Figure 4, at the VMOS of two following brachium pontis pipe short-circuit protection circuit are set.When being arranged on brachium pontis, note making the ground N of short-circuit protection circuit to link to each other with the source class S that is protected power tube.For safer, also can on four brachium pontis, short-circuit protection circuit be set all.Short-circuit protection circuit and above-mentioned short circuit current embodiment are identical, are not described in detail.
Among above short-circuit protection circuit embodiment and the power supply embodiment, bridge circuit is all selected the VMOS pipe for use, and the VMOS pipe is writing a Chinese character in simplified form of Vertical MOSFET, and originally that novel employing is N channel enhancement VMOS, and the electric power metal-oxide-semiconductor mainly also is the N channel enhancement.Except VMOS pipe, other field ring shift switch pipes also can adopt this novel short-circuit protection circuit, like IGBT etc.
Claims (10)
1. power supply with short-circuit protection function; Comprise the bridge circuit that adopts the field ring shift switch pipe; It is characterized in that the switching tube correspondence at least one brachium pontis is provided with short-circuit protection circuit, said short-circuit protection circuit comprises the sampling branch road; The sampling output of sampling branch road connects a judgement branch road, judges the signal output part control connection drive circuit of branch road;
Said sampling branch road comprises first terminals and second terminals that are used to be connected the field ring shift switch management and control system utmost point that are used to connect the field ring shift switch tube anode; Be provided with diode in series (D2) and first resistance (R1) between two terminals; Diode (D2) negative pole connects said first terminals; Diode (D2) is anodal to connect said second terminals, the sampling output of the just very said sampling branch road of said diode (D2) through first resistance (R1);
Said judgement branch road comprises a voltage-stabiliser tube (D1), and this voltage-stabiliser tube (D1) negative pole connects the output of said sampling branch road, and it is anodal through second resistance (R2) ground connection, the signal output part of its just very said judgement branch road (OUT).
2. a kind of power supply with short-circuit protection function according to claim 1 is characterized in that, is provided with first filter capacitor (C1) between said diode (D2) positive pole and the earth point, and said second resistance (R2) is parallelly connected with second filter capacitor (C2).
3. a kind of power supply according to claim 1 and 2 with short-circuit protection function; It is characterized in that; Said drive circuit comprises: triode (Q1), its base stage connects said signal output part (OUT) through a current-limiting resistance (R3), its collector electrode output drive signal.
4. a kind of power supply according to claim 3 with short-circuit protection function; It is characterized in that; Said drive circuit also is connected with buffer circuit: buffer circuit comprises optic coupling element (U1); Between former limit series connection triode (Q1) collector electrode and power supply of optic coupling element, the secondary one end ground connection of optic coupling element (U1), the other end is used to connect the chip pin of corresponding need protection.
5. according to claim 1 or 2 or 4 described a kind of power supplys, it is characterized in that said field ring shift switch pipe is electric power VMOS pipe, said switching tube anode, negative electrode, the drain electrode of the respectively corresponding electric power VMOS pipe of grid, source electrode, grid with short-circuit protection function.
6. a short-circuit protection circuit is characterized in that, said short-circuit protection circuit comprises the sampling branch road, and the sampling output of sampling branch road connects a judgement branch road, judges the signal output part control connection drive circuit of branch road;
Said sampling branch road comprises first terminals and second terminals that are used to be connected the field ring shift switch management and control system utmost point that are used to connect the field ring shift switch tube anode; Be provided with diode in series (D2) and first resistance (R1) between two terminals; Diode (D2) negative pole connects said first terminals; Diode (D2) is anodal to connect said second terminals, the sampling output of the just very said sampling branch road of said diode (D2) through first resistance (R1);
Said judgement branch road comprises a voltage-stabiliser tube (D1), and this voltage-stabiliser tube (D1) negative pole connects the output of said sampling branch road, and it is anodal through second resistance (R2) ground connection, the signal output part of its just very said judgement branch road (OUT).
7. a kind of short-circuit protection circuit according to claim 6 is characterized in that, is provided with first filter capacitor (C1) between said diode (D2) positive pole and the earth point, and said second resistance (R2) is parallelly connected with second filter capacitor (C2).
8. according to claim 6 or 7 described a kind of short-circuit protection circuits, it is characterized in that said drive circuit comprises: triode (Q1), its base stage connects said signal output part (OUT) through a current-limiting resistance (R3), its collector electrode output drive signal.
9. a kind of short-circuit protection circuit according to claim 8; It is characterized in that; Said drive circuit also is connected with buffer circuit: buffer circuit comprises optic coupling element (U1); Between former limit series connection triode (Q1) collector electrode and power supply of optic coupling element, the secondary one end ground connection of optic coupling element (U1), the other end is used to connect the chip pin of corresponding need protection.
10. according to claim 6 or 7 or 9 described a kind of short-circuit protection circuits, it is characterized in that said field ring shift switch pipe is electric power VMOS pipe, said switching tube anode, negative electrode, the drain electrode of the respectively corresponding electric power VMOS pipe of grid, source electrode, grid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120273690XU CN202218005U (en) | 2011-07-29 | 2011-07-29 | Short circuit protecting circuit and power source having short circuit protecting function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120273690XU CN202218005U (en) | 2011-07-29 | 2011-07-29 | Short circuit protecting circuit and power source having short circuit protecting function |
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| Publication Number | Publication Date |
|---|---|
| CN202218005U true CN202218005U (en) | 2012-05-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201120273690XU Expired - Lifetime CN202218005U (en) | 2011-07-29 | 2011-07-29 | Short circuit protecting circuit and power source having short circuit protecting function |
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| CN (1) | CN202218005U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108900101A (en) * | 2018-09-03 | 2018-11-27 | 国网湖北省电力有限公司宜昌供电公司 | A kind of switchgear cowling panel of included defencive function |
| CN110322855A (en) * | 2019-07-11 | 2019-10-11 | 深圳市华星光电技术有限公司 | GOA driving circuit and display device |
| CN112557945A (en) * | 2020-11-18 | 2021-03-26 | 苏州美思迪赛半导体技术有限公司 | Drive port state detection circuit and method |
-
2011
- 2011-07-29 CN CN201120273690XU patent/CN202218005U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108900101A (en) * | 2018-09-03 | 2018-11-27 | 国网湖北省电力有限公司宜昌供电公司 | A kind of switchgear cowling panel of included defencive function |
| CN110322855A (en) * | 2019-07-11 | 2019-10-11 | 深圳市华星光电技术有限公司 | GOA driving circuit and display device |
| CN112557945A (en) * | 2020-11-18 | 2021-03-26 | 苏州美思迪赛半导体技术有限公司 | Drive port state detection circuit and method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20120509 |