CN209072053U - A kind of self- recoverage type current foldback circuit - Google Patents
A kind of self- recoverage type current foldback circuit Download PDFInfo
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- CN209072053U CN209072053U CN201821698384.9U CN201821698384U CN209072053U CN 209072053 U CN209072053 U CN 209072053U CN 201821698384 U CN201821698384 U CN 201821698384U CN 209072053 U CN209072053 U CN 209072053U
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Abstract
The utility model relates to a kind of self- recoverage type current foldback circuits, including power switch tube Q1, triode V4, V5, diode V1, D2, voltage regulator circuit and current sampling circuit, the drain electrode of the power switch tube Q1 is the output end of circuit, the source electrode of power switch tube Q1 and the input terminal of current sampling circuit connect, the grid of power switch tube Q1 is connect through resistance R6 with the collector of triode V5, the base stage of triode V5 is connect through resistance R4 with the anode of diode V1, the emitter of the triode V5 is connect through resistance R5 with its base stage, the cathode of diode V1 is connect with voltage regulator circuit, the anode of diode D2 is connect through resistance R12 with voltage regulator circuit, the cathode of diode D2 is connect with the collector of triode V5.Self- recoverage type current foldback circuit described in the utility model, circuit theory is simple, low in cost, reliable performance and accuracy are high.
Description
Technical field
The utility model relates to switching power circuit technical fields, and in particular to a kind of self- recoverage type current foldback circuit.
Background technique
With Switching Power Supply using the requirement in terms of more and more extensive, perfect control defencive function also increasingly
It is high.The output overcurrent protection of Switching Power Supply is indispensable one in many defencive functions of power supply, and output overcurrent protection can rise
To the protection to power supply itself.The standard brick DC-DC converter of current application all has output overcurrent defencive function, but mostly
The output overcurrent protection of converter protects for locked type rather than hiccup formula type protection.In addition, standard brick DC-DC converter
Output overcurrent protection point is set in inside modules, can not be adjusted in module-external.Therefore, when electrical equipment is wanted
Asking the output overcurrent of power supply to protect is self- recoverage type or the overcurrent when desired output overcurrent protection point with DC-DC converter used
When protection point has deviation, additional output overcurrent protection circuit is just unavoidably needed.
There are many ways to realizing output overcurrent detection, such as carries out the self- recoverage of output overcurrent using hysteresis comparator
Type protection.However, the DC-DC converter of standard brick mostly uses greatly primary-side-control mode, i.e. power management chip and primary side is total
Ground.When this requires carrying out output overcurrent protection using comparator, the auxiliary that comparator power supply is isolated into primary side is also provided
Power circuit.To increase the complexity of power supply control, while also increasing the cost of power supply.
Utility model content
The purpose of this utility model is to provide it is a kind of it is simple and reliable, precision is high, and cheap self- recoverage type overcurrent
Protect circuit.
To achieve the above object, the utility model uses following technical scheme:
A kind of self- recoverage type current foldback circuit, including power switch tube Q1, triode V4, V5, diode V1, D2, surely
Volt circuit and current sampling circuit, the drain electrode of the power switch tube Q1 are the output end of circuit, the source electrode of power switch tube Q1
It being connect with the input terminal of current sampling circuit, the grid of power switch tube Q1 is connect through resistance R6 with the collector of triode V5,
The base stage of triode V5 is connect through resistance R4 with the anode of diode V1, and the emitter of the triode V5 is through resistance R5 and its base
Pole connection, the cathode of diode V1 are connect with voltage regulator circuit, and the anode of diode D2 is connect through resistance R12 with voltage regulator circuit, and two
The cathode of pole pipe D2 is connect with the collector of triode V5.
As a further improvement of the above technical scheme:
The voltage regulator circuit includes accurate adjustable voltage stabilizer N1, and diode D1, resistance R3, R9, R10, the precision is adjustable
The cathode of voltage-stablizer N1 is connect with the first end of resistance R3, and the second end of resistance R3 is connect with circuit input end, accurate adjustable steady
The anode of depressor N1 is successively connected through the anode of resistance R10, R9 and diode D1, and the anode of accurate adjustable voltage stabilizer N1 connects
The reference end on ground, accurate adjustable voltage stabilizer N1 is connect through resistance R12 with the anode of diode D2, and the reference end is through resistance R11
It is connected at the node between resistance R9 and resistance R10.
The current sampling circuit includes triode V3, resistance R1, resistance R7, resistance R8, the transmitting of the triode V3
Pole is connect with the source electrode of power switch tube Q1, and the collector of triode V3 is connect with the base stage of triode V4, the triode V3
Base stage be grounded through resistance R8, which simultaneously connect through resistance R7 with its collector, and the first end of the resistance R1 is opened with power
The source electrode connection of pipe Q1 is closed, the second end of resistance R1 is the input terminal of circuit.
It further include capacitor C1, the capacitor C1 is connected in parallel on the both ends of resistance R10.
As shown from the above technical solution, self- recoverage type current foldback circuit described in the utility model, circuit theory is simple,
The output electric current measure part of low in cost, reliable performance and accuracy height, output overcurrent protection circuit does not need auxiliary power supply,
And current sample is realized by detection resistance R1.After output overcurrent converter shutdown output, when output overcurrent release after, Q1 according to
It is old to be in opening state, to realize that output overcurrent protects self-healing purpose.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the utility model.
Specific embodiment
The utility model is described further with reference to the accompanying drawing:
As shown in Figure 1, the self- recoverage type current foldback circuit of the present embodiment, including power switch tube Q1, triode V4,
V5, diode V1, D2, voltage regulator circuit and current sampling circuit, the drain electrode of power switch tube Q1 are the output end of circuit, and power is opened
The input terminal of the source electrode and current sampling circuit that close pipe Q1 connects, and the grid of power switch tube Q1 is through resistance R6's and triode V5
Collector connection, the base stage of triode V5 are connect through resistance R4 with the anode of diode V1, and the emitter of triode V5 is through resistance
R5 is connect with its base stage, and the cathode of diode V1 is connect with voltage regulator circuit, and the anode of diode D2 is through resistance R12 and voltage regulator circuit
Connection, the cathode of diode D2 are connect with the collector of triode V5.
Voltage regulator circuit includes accurate adjustable voltage stabilizer N1, diode D1, resistance R3, R9, R10, accurate adjustable voltage stabilizer N1
Cathode connect with the first end of resistance R3, the second end of resistance R3 is connect with circuit input end, accurate adjustable voltage stabilizer N1's
Anode is successively connected through the anode of resistance R10, R9 and diode D1, and the plus earth of accurate adjustable voltage stabilizer N1, and precision can
The reference end of voltage-stablizer N1 is adjusted to connect through resistance R12 with the anode of diode D2, and the reference end is connected to resistance through resistance R11
At node between R9 and resistance R10, capacitor C1, capacitor C1 and resistance R10 composition charge and discharge are parallel at the both ends of resistance R10
Circuit.The accurate adjustable voltage stabilizer N1 of the present embodiment uses the chip of model LM431.
Current sampling circuit includes triode V3, resistance R1, resistance R7, resistance R8, the emitter and power of triode V3
The source electrode of switching tube Q1 connects, and the collector of triode V3 is connect with the base stage of triode V4, and the base stage of triode V3 is through resistance
R8 ground connection, the base stage are simultaneously connect through resistance R7 with its collector, and the first end of resistance R1 is connect with the source electrode of power switch tube Q1,
The second end of resistance R1 is the input terminal of circuit.
Circuit operation principle is as follows:
When exporting electric current I0 overcurrent or short circuit, the flow direction of electric current is that input voltage VIN passes through resistance R3, Zener in circuit
Diode V1, resistance R4 and R5 are divided so that NPN triode V5 enters on state, and resistance R2 and resistance R6 partial pressure are so that power
Switching tube Q1 conducting, due to output overcurrent or short circuit, has electric current to flow through on DC bus, generates pressure at the both ends sample resistance R1
Drop, node VF voltage is approximately equal to 0.5V or so, creates condition to the conducting of PNP triode V3, to make PNP triode V3
Into on state, the conducting of triode V3 promotes PNP triode V4 to be connected.The conducting of triode V4 is by resistance R9 to C1 electricity
Appearance charges, C1 capacitor power on full of when, since V5 is on state, resistance R11 and R12 are divided so that model LM431
Accurate adjustable voltage stabilizer N1 become Zener on state from ending, at this time Zener diode V1 by state become end shape
State, Zener diode V1 cut-off, so that NPN triode V5 be made to be not turned on, the cut-off of NPN triode V5 makes power switch tube Q1
Off state is become by state, power switch tube Q1 cuts off DC bus, to realize the effect of protection late-class circuit.It is small
The effect of signal diode D1, D2 are that electric current reverse irrigation is prevented to charge capacitor C1；NPN triode V5 and power switch tube Q1
In the state of all ending, so that PNP triode V4 be made to become off state, PNP triode V4 cut-off, capacitor C1 by state
It is discharged by resistance R10, when the reference voltage terminal of the accurate adjustable voltage stabilizer N1 of LM431 is lower than 2.5V, accurate adjustable voltage stabilizer
N1 becomes off state by state.Current direction at this time is that input voltage VIN passes through resistance R3, and Zener diode V1 is led
It is logical.If late-class circuit goes down lasting hiccup formula work still in overcurrent or short-circuit condition.
When output current IO in the normal range, in circuit the flow direction of electric current be input voltage VIN pass through resistance R3, Zener
Diode V1, resistance R4 and R5 are divided so that NPN triode V5 enters on state, and resistance R2 and R6 are divided so that power switch
Pipe Q1 is connected, and has electric current to flow through on DC bus, generates pressure drop at the both ends sample resistance R1, node VF voltage is approximately equal to input
Voltage VIN is created condition to the conducting of PNP triode V3, to make PNP triode V3 enter on state, due to node
Voltage is approximately equal to input voltage VIN at VF, so triode V4 is unable to saturation conduction, V4 is not turned on, and capacitor C1 does not charge
Circuit is charged, so the reference end of accurate adjustable voltage stabilizer N1 forces accurate adjustable voltage stabilizer N1 without conducting voltage
It cannot be connected, Zener diode V1 will be constantly on, and triode V5, power tube Q1 will be constantly on, provides energy for late-class circuit
Amount.
Embodiment described above is only that preferred embodiments of the present invention are described, not practical to this
Novel range is defined, and under the premise of not departing from the spirit of the design of the utility model, those of ordinary skill in the art are to this
The various changes and improvements that the technical solution of utility model is made should all fall into the protection that the utility model claims book determines
In range.
Claims (4)
1. a kind of self- recoverage type current foldback circuit, it is characterised in that: including power switch tube Q1, triode V4, V5, diode
V1, D2, voltage regulator circuit and current sampling circuit, the drain electrode of the power switch tube Q1 are the output end of circuit, power switch tube
The source electrode of Q1 and the input terminal of current sampling circuit connect, current collection of the grid of power switch tube Q1 through resistance R6 Yu triode V5
Pole connection, the base stage of triode V5 are connect through resistance R4 with the anode of diode V1, and the emitter of the triode V5 is through resistance
R5 is connect with its base stage, and the cathode of diode V1 is connect with voltage regulator circuit, and the anode of diode D2 is through resistance R12 and voltage regulator circuit
Connection, the cathode of diode D2 are connect with the collector of triode V5.
2. self- recoverage type current foldback circuit according to claim 1, it is characterised in that: the voltage regulator circuit includes precision
Adjustable voltage stabilizer N1, diode D1, resistance R3, R9, R10, the cathode and the first of resistance R3 of the precision adjustable voltage stabilizer N1
End connection, the second end of resistance R3 are connect with circuit input end, and the anode of accurate adjustable voltage stabilizer N1 is successively through resistance R10, R9
It is connect with the anode of diode D1, and the plus earth of accurate adjustable voltage stabilizer N1, the reference end warp of accurate adjustable voltage stabilizer N1
Resistance R12 is connect with the anode of diode D2, and the reference end is connected to the section between resistance R9 and resistance R10 through resistance R11
At point.
3. self- recoverage type current foldback circuit according to claim 1, it is characterised in that: the current sampling circuit includes
Triode V3, resistance R1, resistance R7, resistance R8, the emitter of the triode V3 are connect with the source electrode of power switch tube Q1, and three
The collector of pole pipe V3 is connect with the base stage of triode V4, and the base stage of the triode V3 is grounded through resistance R8, which simultaneously passes through
Resistance R7 is connect with its collector, and the first end of the resistance R1 is connect with the source electrode of power switch tube Q1, and the second of resistance R1
End is the input terminal of circuit.
4. self- recoverage type current foldback circuit according to claim 2, it is characterised in that: further include capacitor C1, the electricity
Hold the both ends that C1 is connected in parallel on resistance R10.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821293759 | 2018-08-10 | ||
| CN2018212937593 | 2018-08-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209072053U true CN209072053U (en) | 2019-07-05 |
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ID=67095310
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821698384.9U Expired - Fee Related CN209072053U (en) | 2018-08-10 | 2018-10-12 | A kind of self- recoverage type current foldback circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209072053U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149523A (en) * | 2018-08-10 | 2019-01-04 | 合肥华耀电子工业有限公司 | A kind of self- recoverage type current foldback circuit |
-
2018
- 2018-10-12 CN CN201821698384.9U patent/CN209072053U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149523A (en) * | 2018-08-10 | 2019-01-04 | 合肥华耀电子工业有限公司 | A kind of self- recoverage type current foldback circuit |
| CN109149523B (en) * | 2018-08-10 | 2024-02-20 | 合肥华耀电子工业有限公司 | Self-recovery type overcurrent protection circuit |
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| Date | Code | Title | Description |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190705 |