CN202888807U - Overcurrent protection circuit and switch power supply for half-bridge circuit - Google Patents
Overcurrent protection circuit and switch power supply for half-bridge circuit Download PDFInfo
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- CN202888807U CN202888807U CN 201220421437 CN201220421437U CN202888807U CN 202888807 U CN202888807 U CN 202888807U CN 201220421437 CN201220421437 CN 201220421437 CN 201220421437 U CN201220421437 U CN 201220421437U CN 202888807 U CN202888807 U CN 202888807U
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Abstract
The utility model discloses an overcurrent protection circuit and a switch power supply for a half-bridge circuit. The overcurrent protection circuit comprises a first driving-source input terminal, a second driving-source input terminal, a first switch tube, a second switch tube, a current sampling circuit, a thyristor self-locking circuit, a first protection circuit and a second protection circuit. The current sampling circuit is connected between a source electrode of the second switch tube and a control terminal of the thyristor self-locking circuit. The first protection circuit is connected between the thyristor self-locking circuit and a grid electrode of the first switch tube. The grid electrode of the first switch tube is also connected with the first driving-source input terminal. The second protection circuit is connected between the thyristor self-locking circuit and a grid electrode of the second switch tube. The grid electrode of the second switch tube is also connected with the second driving-source input terminal. A drain electrode of the first switch tube is connected with a power-supply input terminal, and a source electrode of the first switch tube is connected with a power-supply output terminal and a drain electrode of the second switch tube. Compared with the overcurrent protection circuit in the half-bridge circuit in the prior art, circuit cost is reduced.
Description
Technical field
The utility model relates to the switch power technology field, particularly a kind of current foldback circuit of half-bridge circuit and Switching Power Supply.
Background technology
At present, the power supply of a lot of electronic products all adopts Switching Power Supply, and existing Switching Power Supply is divided into single-tube Switching Power Supply and multi-pipe type Switching Power Supply, because the multi-pipe type Switching Power Supply has advantages of that power output is large, so that the multi-pipe type Switching Power Supply has obtained widely application, and half-bridge circuit is exactly a kind of multi-pipe type switching power circuit of commonly using.But, when the electric current that flows through switching tube in the half-bridge circuit is excessive, then can cause the damage of switching tube, thereby cause the irregular working of whole half-bridge circuit, therefore, half-bridge circuit is applied current foldback circuit just seem particularly important.
As shown in Figure 1; Fig. 1 is the electrical block diagram of a kind of current foldback circuit of half-bridge circuit in the prior art, and this circuit comprises power input V_IN, MOS switching tube M1, MOS switching tube M2, drive source Vg11, drive source Vg12, NPN triode Q11, diode D11, D12, D13, D14, optocoupler P1, thyristor S11, power supply VCC1, resistance R 11, R12, R13, R14, R15, R16, R17, R18, R19 and filter capacitor C11.Particularly, after diode D11 and resistance R 11 were in parallel, its negative electrode was connected with drive source Vg11, and its anode is connected through the grid of resistance R 12 with MOS switching tube M1, the drain electrode of MOS switching tube M1 is connected with power input V_IN, and its source electrode is connected with the drain electrode of MOS switching tube M2; After diode D12 and resistance R 14 are in parallel, its negative electrode is connected with drive source Vg12 through resistance R 13, its anode is connected with the grid of MOS switching tube M2, the source electrode of MOS switching tube M2 is current sampling resistor through resistance R 18(resistance R 18) ground connection, the source electrode of MOS switching tube M2 also is connected with the end of filter capacitor C11 through resistance R 17, the ground end G2 of another termination drive source Vg12 of filter capacitor C11;
Power supply VCC1 is through the anodic bonding of resistance R 19 with the transmitting terminal diode of optocoupler P1, the negative electrode of the transmitting terminal diode of optocoupler P1 is connected with the negative electrode of diode D14, the anode of diode D14 is connected with the grid of MOS switching tube M2, the anode of thyristor S11 is connected with the negative electrode of diode D14, the negative electrode of thyristor S11 meets the ground end G2 of drive source Vg12, the control utmost point of thyristor S11 is connected between resistance R 17 and the filter capacitor C11, the collector electrode of the receiving terminal of optocoupler P1 is connected with drive source Vg11 through resistance R 15, the emitter of the receiving terminal of optocoupler P1 is connected with the base stage of NPN triode Q11, the collector electrode of NPN triode Q11 and the anodic bonding of diode D11, the emitter of NPN triode Q11 and the anodic bonding of diode D13, the minus earth of diode D13, one end of resistance R 16 is connected with the base stage of NPN triode Q11, its other end ground connection.
Circuit shown in Figure 1, when resistance R 18 samples over-current signal, thyristor S11 is with conducting, thereby so that the grid potential of MOS switching tube M2 is clamped at low level, thereby so that MOS switching tube M2 cut-off, simultaneously, when thyristor S11 conducting, the grid potential of MOS switching tube M1 also is clamped at low level by optocoupler P1, thereby so that MOS switching tube M1 cut-off, namely when this circuit generation overcurrent, the MOS switching tube M1 in the circuit and MOS switching tube M2 are in cut-off state, thereby have avoided MOS switching tube M1 and MOS switching tube M2 damaged because over-current phenomenon avoidance occurs.Yet also there is following defective in circuit shown in Figure 1: (1) closes the expensive price of coupling P1, and its reliability is not high yet; (2) when interference signal is arranged, the phenomenon that NPN triode Q11 can occur misleading, it might cause the damage of MOS switching tube M1; (3) NPN triode Q11 need to adopt withstand voltage high NPN triode, and the price of withstand voltage high NPN triode is more expensive.
The utility model content
Main purpose of the present utility model provides a kind of current foldback circuit of half-bridge circuit, is intended to avoid the switching tube in the half-bridge circuit damaged because of overcurrent, simultaneously, reduces the cost of circuit, improves the reliability of circuit.
The utility model proposes a kind of current foldback circuit of half-bridge circuit, the current foldback circuit of described half-bridge circuit comprises power input, power output end, the first drive source input, the second drive source input, the first switching tube, the second switch pipe, the current sampling circuit that is used for the sampling over-current signal, be used for the thyristor latching circuit according to described over-current signal triggering for generating the first guard signal and the second guard signal, for generation of described the first guard signal to the grid of described the first switching tube to turn-off the first protective circuit of described the first switching tube, and for generation of described the second guard signal to the grid of described second switch pipe to turn-off the second protective circuit of described second switch pipe; Wherein:
The sampling input of current sampling circuit is connected with the source electrode of second switch pipe, and its sampling output is connected with the control end of thyristor latching circuit; The first protective circuit is connected between the grid of thyristor latching circuit and the first switching tube, and the grid of the first switching tube also is connected with the first drive source input; The second protective circuit is connected between the grid of thyristor latching circuit and second switch pipe, and the grid of second switch pipe also is connected with the second drive source input; The drain electrode of the first switching tube is connected with power input, and source electrode is connected with power output end, and is connected with the drain electrode of second switch pipe.
Preferably, described current sampling circuit comprises current sampling resistor and the first resistance; Wherein:
One end of current sampling resistor is connected with the source electrode of described second switch pipe, and is connected through the control end of the first resistance with described thyristor latching circuit, the other end ground connection of current sampling resistor.
Preferably, described thyristor latching circuit comprises accessory power supply input, the second resistance, diode and thyristor; Wherein:
The control utmost point of thyristor is connected with the source electrode of described second switch pipe through described the first resistance; the anode of thyristor is connected with the negative electrode of diode; and be connected with described the first protective circuit; the negative electrode of thyristor is connected with described the second protective circuit, and the anode of diode is connected with the accessory power supply input through the second resistance.
Preferably, described the first protective circuit comprises the 3rd resistance, the 4th resistance and the first triode, and described the first triode is the PNP triode; Wherein:
One end of the 3rd resistance and the anodic bonding of described thyristor, the other end of the 3rd resistance is connected with the base stage of the first triode, and be connected with emitter and the described first drive source input of the first triode respectively through the 4th resistance, described the first drive source input also is connected with the grid of described the first switching tube, the collector electrode of the first triode is connected with described power output end, and is connected with the source electrode of described the first switching tube and the drain electrode of described second switch pipe.
Preferably, described the second protective circuit comprises the 5th resistance, the 6th resistance and the second triode, and described the second triode is the NPN triode; Wherein:
One end of the 5th resistance is connected with the negative electrode of described thyristor, and be connected through the base stage of the 6th resistance with the second triode, the collector electrode of the second triode is connected with described the second drive source input, described the second drive source input also is connected the grounded emitter of the second triode with the grid of described second switch pipe.
Preferably, also comprise the 7th resistance and the 8th resistance; Wherein:
The 7th resistance is connected between the grid of described the first drive source input and described the first switching tube; The 8th resistance is connected between the grid of described the second drive source input and described second switch pipe.
Preferably, described the first switching tube and described second switch pipe are the MOS switching tube.
The utility model also proposes a kind of Switching Power Supply, described Switching Power Supply comprises the current foldback circuit of half-bridge circuit, and the current foldback circuit of described half-bridge circuit comprises power input, power output end, the first drive source input, the second drive source input, the first switching tube, the second switch pipe, the current sampling circuit that is used for the sampling over-current signal, be used for the thyristor latching circuit according to described over-current signal triggering for generating the first guard signal and the second guard signal, for generation of described the first guard signal to the grid of described the first switching tube to turn-off the first protective circuit of described the first switching tube, and for generation of described the second guard signal to the grid of described second switch pipe to turn-off the second protective circuit of described second switch pipe; Wherein:
The sampling input of current sampling circuit is connected with the source electrode of second switch pipe, and its sampling output is connected with the control end of thyristor latching circuit; The first protective circuit is connected between the grid of thyristor latching circuit and the first switching tube, and the grid of the first switching tube also is connected with the first drive source input; The second protective circuit is connected between the grid of thyristor latching circuit and second switch pipe, and the grid of second switch pipe also is connected with the second drive source input; The drain electrode of the first switching tube is connected with power input, and source electrode is connected with power output end, and is connected with the drain electrode of second switch pipe.
The current foldback circuit of the half-bridge circuit that the utility model proposes; when current sampling circuit samples over-current signal; trigger the first protective circuit by the thyristor latching circuit and produce the grid of the first guard signal to the first switching tube to turn-off the first switching tube; and trigger the second protective circuit produce the second guard signal to the grid of second switch pipe turn-offing the second switch pipe, thereby avoided the first switching tube and second switch pipe damaged because of overcurrent.The current foldback circuit of this half-bridge circuit that the utility model proposes; because the withstand voltage height of the thyristor in its thyristor latching circuit; and its low price; simultaneously; triode in its first protective circuit and the second protective circuit can adopt withstand voltage low triode; and the price of withstand voltage low triode is low; and it is stable and reliable for performance; thereby so that the utility model is with respect to the current foldback circuit of half-bridge circuit of the prior art; the reliability that has greatly reduced the cost of circuit and improved circuit; simultaneously, the utility model also has advantages of circuit structure simply and easily realization.
Description of drawings
Fig. 1 is the electrical block diagram of a kind of current foldback circuit of half-bridge circuit in the prior art;
Fig. 2 is the electrical block diagram of the current foldback circuit preferred embodiment of the utility model half-bridge circuit.
The realization of the utility model purpose, functional characteristics and advantage are described further with reference to accompanying drawing in connection with embodiment.
Embodiment
Should be appreciated that specific embodiment described herein only in order to explaining the utility model, and be not used in restriction the utility model.
Fig. 2 is the electrical block diagram of the current foldback circuit preferred embodiment of the utility model half-bridge circuit.
With reference to Fig. 2, the current foldback circuit of the utility model half-bridge circuit comprises power input HV_IN, power output end HV_OUT, the first drive source input Vg1, the second drive source input Vg2, the first switching tube 101, second switch pipe 102, current sampling circuit 103, thyristor latching circuit 104, the first protective circuit 105 and the second protective circuit 106.In the present embodiment, the first switching tube 101 and second switch pipe 102 are the MOS switching tube.
Wherein, current sampling circuit 103 is used for the sampling over-current signal; thyristor latching circuit 104 is for the over-current signal that samples according to current sampling circuit 103; triggering the first protective circuit 105 produces the first guard signal and triggers the second protective circuit 106 generations the second guard signal; the first protective circuit 105 is used for producing the first guard signal to the first switching tube 101 when current sampling circuit 103 samples over-current signal grid with turn-off the first switching tube 101, the second protective circuits 106 be used for when current sampling circuit 103 samples over-current signal, producing the second guard signal to the grid of second switch pipe 102 to turn-off second switch pipe 102.
Particularly, the sampling input of current sampling circuit 103 is connected with the source electrode of second switch pipe 102, and the sampling output of current sampling circuit 103 is connected with the control end of thyristor latching circuit 104; The first protective circuit 105 is connected between the grid of thyristor latching circuit 104 and the first switching tube 101, and the grid of the first switching tube 101 also is connected with the first drive source input Vg1; The second protective circuit 106 is connected between the grid of thyristor latching circuit 104 and second switch pipe 102, and the grid of second switch pipe 102 also is connected with the second drive source input Vg2; The drain electrode of the first switching tube 101 is connected with power input HV_IN, and the source electrode of the first switching tube 101 is connected with power output end HV_OUT, and is connected with the drain electrode of second switch pipe 102.
Wherein, above-mentioned current sampling circuit 103 comprises current sampling resistor RS and the first resistance R 1.Particularly, the end of current sampling resistor RS is connected with the source electrode of second switch pipe 102, and is connected the other end ground connection of current sampling resistor RS with the control end of thyristor latching circuit 104 through the first resistance R 1;
Above-mentioned thyristor latching circuit 104 comprises accessory power supply input VCC2, the second resistance R 2, diode D1 and thyristor S1, and in the present embodiment, the voltage of accessory power supply input VCC2 is 12V.Particularly, the control utmost point of thyristor S1 is connected with the source electrode of second switch pipe 102 through the first resistance R 1, the anode of thyristor S1 is connected with the negative electrode of diode D1, and be connected with the first protective circuit 105, the negative electrode of thyristor S1 is connected with the second protective circuit 106, and the anode of diode D1 is connected with accessory power supply input VCC2 through the second resistance R 2;
Above-mentioned the first protective circuit 105 comprises the 3rd resistance R 3, the 4th resistance R 4 and the first triode Q1, and in the present embodiment, the first triode Q1 is the PNP triode.Particularly, one end of the 3rd resistance R 3 and the anodic bonding of thyristor S1, the other end of the 3rd resistance R 3 is connected with the base stage of the first triode Q1, and be connected with emitter and the first drive source input Vg1 of the first triode Q1 respectively through the 4th resistance R 4, the first drive source input Vg1 also is connected with the grid of the first switching tube 101, the collector electrode of the first triode Q1 is connected with power output end HV_OUT, and is connected with the source electrode of the first switching tube 101 and the drain electrode of second switch pipe 102;
Above-mentioned the second protective circuit 106 comprises the 5th resistance R 5, the 6th resistance R 6 and the second triode Q2, and in the present embodiment, the second triode Q2 is the NPN triode.Particularly, one end of the 5th resistance R 5 is connected with the negative electrode of thyristor S1, and be connected with the base stage of the second triode Q2 through the 6th resistance R 6, the collector electrode of the second triode Q2 is connected with the second drive source input Vg2, the second drive source input Vg2 also is connected the grounded emitter of the second triode Q2 with the grid of second switch pipe Q2;
Preferably, above-described embodiment of the present utility model also comprises the 7th resistance R 7 and the 8th resistance R 8, and wherein, the 7th resistance R 7 is connected between the grid of the first drive source input Vg1 and the first switching tube 101; The 8th resistance R 8 is connected between the grid of the second drive source input Vg2 and second switch pipe 102.
The operation principle of the current foldback circuit of the utility model half-bridge circuit specifically describes as follows: when current sampling circuit 103 samples over-current signal; be that the electric current of current flowing sample resistance RS is when excessive; the voltage of the control utmost point of thyristor S1 will be more than or equal to its conducting control voltage; so that thyristor S1 conducting; and the conducting of thyristor S1 will trigger the second triode Q2 conducting; so that the current potential of second switch pipe 102 grids is dragged down; thereby so that second switch pipe 102 turn-offs; simultaneously; the conducting of thyristor S1 also can trigger the first triode Q1 conducting; so that the current potential of the first switching tube 101 grids is dragged down; thereby so that the first switching tube 101 turn-offs, thereby avoided the first switching tube 101 and second switch pipe 102 damaged because of overcurrent.And; in the present embodiment; when thyristor S1 conducting; the 12V voltage of accessory power supply input VCC2 provides latching current by the second resistance R 2 and diode D1 for thyristor S1; make thyristor S1 self-locking; namely after circuit generation over-current phenomenon avoidance makes thyristor S1 conducting, thyristor S1 will be in conducting state always, thereby well realize overcurrent protection purpose of the present utility model.
The current foldback circuit of the half-bridge circuit that the utility model proposes; when current sampling circuit samples over-current signal; trigger the first protective circuit by the thyristor latching circuit and produce the grid of the first guard signal to the first switching tube to turn-off the first switching tube; and trigger the second protective circuit produce the second guard signal to the grid of second switch pipe turn-offing the second switch pipe, thereby avoided the first switching tube and second switch pipe damaged because of overcurrent.The current foldback circuit of this half-bridge circuit that the utility model proposes; because the withstand voltage height of the thyristor in its thyristor latching circuit; and its low price; simultaneously; triode in its first protective circuit and the second protective circuit can adopt withstand voltage low triode; and the price of withstand voltage low triode is low; and it is stable and reliable for performance; thereby so that the utility model is with respect to the current foldback circuit of half-bridge circuit of the prior art; the reliability that has greatly reduced the cost of circuit and improved circuit; simultaneously, the utility model also has advantages of circuit structure simply and easily realization.
The utility model also proposes a kind of Switching Power Supply; this Switching Power Supply comprises the current foldback circuit of half-bridge circuit; the circuit structure of the current foldback circuit of its half-bridge circuit is identical with the circuit structure of the current foldback circuit of the described half-bridge circuit of top embodiment, repeats no more herein.
The above only is preferred embodiment of the present utility model; be not so limit claim of the present utility model; every equivalent structure or equivalent flow process conversion that utilizes the utility model specification and accompanying drawing content to do; or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present utility model.
Claims (8)
1. the current foldback circuit of a half-bridge circuit comprises power input, power output end, the first drive source input, the second drive source input, the first switching tube and second switch pipe; It is characterized in that, also comprise current sampling circuit for the sampling over-current signal, be used for according to described over-current signal triggering for generating the first guard signal and the second guard signal the thyristor latching circuit, for generation of described the first guard signal to the grid of described the first switching tube with first protective circuit of turn-offing described the first switching tube and for generation of described the second guard signal to the grid of described second switch pipe to turn-off the second protective circuit of described second switch pipe; Wherein:
The sampling input of current sampling circuit is connected with the source electrode of second switch pipe, and its sampling output is connected with the control end of thyristor latching circuit; The first protective circuit is connected between the grid of thyristor latching circuit and the first switching tube, and the grid of the first switching tube also is connected with the first drive source input; The second protective circuit is connected between the grid of thyristor latching circuit and second switch pipe, and the grid of second switch pipe also is connected with the second drive source input; The drain electrode of the first switching tube is connected with power input, and source electrode is connected with power output end, and is connected with the drain electrode of second switch pipe.
2. circuit according to claim 1 is characterized in that, described current sampling circuit comprises current sampling resistor and the first resistance; Wherein:
One end of current sampling resistor is connected with the source electrode of described second switch pipe, and is connected through the control end of the first resistance with described thyristor latching circuit, the other end ground connection of current sampling resistor.
3. circuit according to claim 2 is characterized in that, described thyristor latching circuit comprises accessory power supply input, the second resistance, diode and thyristor; Wherein:
The control utmost point of thyristor is connected with the source electrode of described second switch pipe through described the first resistance; the anode of thyristor is connected with the negative electrode of diode; and be connected with described the first protective circuit; the negative electrode of thyristor is connected with described the second protective circuit, and the anode of diode is connected with the accessory power supply input through the second resistance.
4. circuit according to claim 3 is characterized in that, described the first protective circuit comprises the 3rd resistance, the 4th resistance and the first triode, and described the first triode is the PNP triode; Wherein:
One end of the 3rd resistance and the anodic bonding of described thyristor, the other end of the 3rd resistance is connected with the base stage of the first triode, and be connected with emitter and the described first drive source input of the first triode respectively through the 4th resistance, described the first drive source input also is connected with the grid of described the first switching tube, the collector electrode of the first triode is connected with described power output end, and is connected with the source electrode of described the first switching tube and the drain electrode of described second switch pipe.
5. circuit according to claim 4 is characterized in that, described the second protective circuit comprises the 5th resistance, the 6th resistance and the second triode, and described the second triode is the NPN triode; Wherein:
One end of the 5th resistance is connected with the negative electrode of described thyristor, and be connected through the base stage of the 6th resistance with the second triode, the collector electrode of the second triode is connected with described the second drive source input, described the second drive source input also is connected the grounded emitter of the second triode with the grid of described second switch pipe.
6. circuit according to claim 1 is characterized in that, also comprises the 7th resistance and the 8th resistance; Wherein:
The 7th resistance is connected between the grid of described the first drive source input and described the first switching tube; The 8th resistance is connected between the grid of described the second drive source input and described second switch pipe.
7. circuit according to claim 1 is characterized in that, described the first switching tube and described second switch pipe are the MOS switching tube.
8. a Switching Power Supply is characterized in that, comprises the current foldback circuit of each described half-bridge circuit among the claim 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220421437 CN202888807U (en) | 2012-08-23 | 2012-08-23 | Overcurrent protection circuit and switch power supply for half-bridge circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220421437 CN202888807U (en) | 2012-08-23 | 2012-08-23 | Overcurrent protection circuit and switch power supply for half-bridge circuit |
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| CN202888807U true CN202888807U (en) | 2013-04-17 |
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| CN 201220421437 Expired - Fee Related CN202888807U (en) | 2012-08-23 | 2012-08-23 | Overcurrent protection circuit and switch power supply for half-bridge circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104684188A (en) * | 2013-12-03 | 2015-06-03 | 深圳市海洋王照明工程有限公司 | LED (Light-emitting Diode) drive circuit and mine explosion-proof lamp |
| CN104836441A (en) * | 2014-04-09 | 2015-08-12 | 北汽福田汽车股份有限公司 | Electric vehicle and DC/DC converting device of vehicle-mounted power supply used in electric vehicle |
-
2012
- 2012-08-23 CN CN 201220421437 patent/CN202888807U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104684188A (en) * | 2013-12-03 | 2015-06-03 | 深圳市海洋王照明工程有限公司 | LED (Light-emitting Diode) drive circuit and mine explosion-proof lamp |
| CN104684188B (en) * | 2013-12-03 | 2019-01-18 | 深圳市海洋王照明工程有限公司 | A kind of LED drive circuit and flameproof luminaire |
| CN104836441A (en) * | 2014-04-09 | 2015-08-12 | 北汽福田汽车股份有限公司 | Electric vehicle and DC/DC converting device of vehicle-mounted power supply used in electric vehicle |
| CN104836441B (en) * | 2014-04-09 | 2017-10-10 | 北汽福田汽车股份有限公司 | Electric automobile and the DC/DC converting means for its vehicle power |
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Granted publication date: 20130417 Termination date: 20200823 |
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| CF01 | Termination of patent right due to non-payment of annual fee |