CN203536941U - A high-definition input overvoltage protection circuit of a self-oscillation flyback converter - Google Patents
A high-definition input overvoltage protection circuit of a self-oscillation flyback converter Download PDFInfo
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- CN203536941U CN203536941U CN201320687640.5U CN201320687640U CN203536941U CN 203536941 U CN203536941 U CN 203536941U CN 201320687640 U CN201320687640 U CN 201320687640U CN 203536941 U CN203536941 U CN 203536941U
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Abstract
Provided is a high-definition input overvoltage protection circuit of a self-oscillation flyback converter. The high-definition input overvoltage protection circuit comprises a transformer, a MOS transistor, a current-limiting resistor, an auxiliary coil, a PNP-type triode, and a NPN-type triode. The auxiliary coil is connected with the gate electrode of the MOS transistor successively via a capacitor C3 and a resistor R5. A voltage input end Vin+ is connected with ground successively through a resistor R1 and a resistor R101. The gate electrode of the MOS transistor is connected with the cathode connection end of a reference source chip. The anode connection end of the reference source chip is connected with ground. The reference voltage connection end of the reference source chip is connected with a junction of the resistor R1 and the resistor R101. By adding the resistor R1, the resistor R101, and the reference voltage source, an overvoltage point at the voltage input end can be well controlled. And the voltage of the gate electrode of the MOS transistor can be accurately reduced when surge voltage or abnormal high voltage occurs to the voltage input end such that circuit output can be fast turned off and the normal operation of the circuit of an entire system is protected.
Description
Technical field
The utility model relates to switching power converters technical field, is specifically related to a kind of high accuracy protection circuit against input over-voltage of self-oscillation flyback converter.
Background technology
Self-oscillation flyback converter comprises coupling transformer, field effect transistor, the brilliant utmost point pipe of vibration, when Input voltage terminal adds after voltage, and produces after self-oscillation work, and circuit can carry out flyback.Existing self-oscillation flyback converter is when the voltage of Input voltage terminal is higher, especially the moment that voltage has just been inputted, on voltage input end, easily produce a very large transient current spike, make the instantaneous conducting of transistor, this transient current spike just likely makes transistor breakdown, the too high voltages being simultaneously added on pipe also can make transistor damage, also will cause the problem of product poor starting.
Utility model content
The utility model provides a kind of high accuracy protection circuit against input over-voltage of self-oscillation flyback converter, can address the above problem.
The high accuracy protection circuit against input over-voltage of a kind of self-oscillation flyback converter that the utility model embodiment provides, comprise: transformer T1, metal-oxide-semiconductor and current-limiting resistance R9, voltage input end Vin+ passes through the primary coil of transformer T1 successively, the drain electrode of metal-oxide-semiconductor and source electrode, current-limiting resistance R9 ground connection, coupling energy on transformer T1 secondary coil is exported to voltage output end Vo through rectifying tube D2 and energy storage filter capacitor C10 successively, the also grid power supply to metal-oxide-semiconductor through a bleeder circuit of voltage input end Vin+, also comprise: with the ancillary coil T2 of transformer T1 coupling, positive-negative-positive triode Q2 and NPN type triode Q3, ancillary coil one end ground connection other end is connected to the grid of metal-oxide-semiconductor successively through a capacitor C 3 and resistance R 5, metal-oxide-semiconductor grid is successively through a resistance R 6, one resistance R 7, the collector and emitter ground connection of NPN type triode Q3, the described other end of ancillary coil connects the base stage of NPN type triode Q3 through a capacitor C 5, the base stage of NPN type triode Q3 connects the source electrode of metal-oxide-semiconductor by a resistance R 8, the emitter of positive-negative-positive triode connects the grid of metal-oxide-semiconductor, the collector electrode of positive-negative-positive triode connects the source electrode of metal-oxide-semiconductor, the base stage of positive-negative-positive triode Q2 is connected on the tie point of resistance R 6 and resistance R 7, between the source electrode of metal-oxide-semiconductor and NPN type triode Q3, be connected a capacitor C 6, voltage input end Vin+ is successively through a resistance R 1 and resistance R 101 ground connection, the grid of metal-oxide-semiconductor connects the cathode connection terminal of an a reference source chip, the anodic bonding end ground connection of this reference source chip, the base pressure link of this reference source chip is connected on the tie point of resistance R 1 and resistance R 101.
Preferably, a filter capacitor C101 in parallel in resistance R 1.
Preferably, described bleeder circuit comprises: resistance R 2, resistance R 3 and the resistance R 4 of connecting successively, and voltage input end Vin+ passes through resistance R 2, resistance R 3 and resistance R 4 ground connection successively, and the tie point of resistance R 3 and resistance R 4 is connected to the grid of metal-oxide-semiconductor.
Preferably, voltage input end Vin+ is through capacitor C 1 ground connection.
Preferably, energy storage filter capacitor C10 exports to voltage output end Vo through an inductance L 1.
Preferably, also comprise an optocoupler feedback loop, optocoupler feedback loop detects the voltage on energy storage filter capacitor C10 and feeds back to the base stage of NPN type triode Q3.
Technique scheme can be found out, with respect to existing self-oscillation flyback converter, self-oscillation flyback converter in the utility model embodiment can drag down by the grid voltage metal-oxide-semiconductor when Input voltage terminal exists too high voltages, thereby breaking circuit output, effectively guaranteed circuit safety work, and circuit working is stable, reliability is high.
Accompanying drawing explanation
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is circuit theory diagrams in the utility model embodiment.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is clearly and completely described, obviously, described embodiment is only the utility model part embodiment, rather than whole embodiment.Embodiment based in the utility model, those of ordinary skills are not making all other embodiment that obtain under creative work prerequisite, all belong to the scope of the utility model protection.
Embodiment:
The utility model embodiment provides a kind of high accuracy protection circuit against input over-voltage of self-oscillation flyback converter, as shown in Figure 1, comprise: transformer T1, metal-oxide-semiconductor Q1 and current-limiting resistance R9, voltage input end Vin+ passes through the primary coil of transformer T1 successively, the drain electrode of metal-oxide-semiconductor Q1 and source electrode, current-limiting resistance R9 ground connection, coupling energy on transformer T1 secondary coil is exported to voltage output end Vo through rectifying tube D2 and energy storage filter capacitor C10 successively, the also grid power supply to metal-oxide-semiconductor through a bleeder circuit of voltage input end Vin+, the high accuracy protection circuit against input over-voltage of this self-oscillation flyback converter also comprises: with the ancillary coil T2 of transformer T1 coupling, positive-negative-positive triode Q2 and NPN type triode Q3, ancillary coil T2 one end ground connection other end is connected to the grid of metal-oxide-semiconductor Q1 successively through a capacitor C 3 and resistance R 5, metal-oxide-semiconductor Q1 grid is successively through a resistance R 6, one resistance R 7, the collector and emitter ground connection of NPN type triode Q3, the described other end of ancillary coil T2 connects the base stage of NPN type triode Q3 through a capacitor C 5, the base stage of NPN type triode Q3 connects the source electrode of metal-oxide-semiconductor by a resistance R 8, the emitter of positive-negative-positive triode connects the grid of metal-oxide-semiconductor, the collector electrode of positive-negative-positive triode connects the source electrode of metal-oxide-semiconductor, the base stage of positive-negative-positive triode Q2 is connected on the tie point of resistance R 6 and resistance R 7, between the source electrode of metal-oxide-semiconductor and NPN type triode Q3, be connected a capacitor C 6, voltage input end Vin+ is successively through a resistance R 1 and resistance R 101 ground connection, the grid of metal-oxide-semiconductor connects the cathode connection terminal of an a reference source chip, the anodic bonding end ground connection of this reference source chip, the base pressure link of this reference source chip is connected on the tie point of resistance R 1 and resistance R 101.
In order to increase the compatibility of the present embodiment circuit, the base stage of NPN type triode Q3 through a resistance R 10 be connected to one for to Switching Power Supply, provide feedback signal FEEDBACK CONTROL end CTRL.
For the further interference to minimizing input, a filter capacitor C101 in parallel in resistance R 1 in the utility model embodiment.Voltage input end Vin+, through capacitor C 1 ground connection, can further reduce the interference that input causes.Between the grid of metal-oxide-semiconductor Q1 and the base stage of positive-negative-positive triode Q2, be connected a capacitor C 4.
By adding divider resistance R1, divider resistance R101, reference voltage source IC2 and anti-interference capacitor C 101; can well control the pressure point of crossing of voltage input end Vin+; when appearring in voltage input end Vin+, surge voltage or abnormal pressure can timely and accurately the grid voltage of metal-oxide-semiconductor Q1 be dragged down; the output of breaking circuit fast, the normal work of protection whole system circuit.
In order to reduce the stable of circuit output signal, reduce to disturb, energy storage filter capacitor C10 exports to voltage output end Vo through an inductance L 1.
Described in the utility model embodiment, bleeder circuit comprises: resistance R 2, resistance R 3 and the resistance R 4 of connecting successively, and voltage input end Vin+ passes through resistance R 2, resistance R 3 and resistance R 4 ground connection successively, and the tie point of resistance R 3 and resistance R 4 is connected to the grid of metal-oxide-semiconductor.A two ends capacitor C 2 in parallel of the series arm that resistance R 3 and resistance R 4 form, to reduce interference signal.
Self-oscillation flyback converter in the utility model embodiment also comprises an optocoupler feedback loop, and optocoupler feedback loop detects the voltage on energy storage filter capacitor C10 and feeds back to the base stage of NPN type triode Q3.Particularly, optocoupler feedback loop comprises: opto-coupler chip U1, diode D1, a reference source chip IC 1, wherein the anode of the photodiode in opto-coupler chip U1 is connected on energy storage filter capacitor C10 through a resistance R 11, for detection of the voltage on energy storage filter capacitor C10, and then output voltage is fed back to detection, the negative electrode of the photodiode in opto-coupler chip U1 connects the cathode connection terminal of a reference source chip IC 1, the anodic bonding end ground connection of a reference source chip U1, voltage output end Vo is connected power supply ground through resistance R 13 successively with resistance R 14, between power supply ground and the earth, be connected a capacitor C 9, the base pressure link of a reference source chip IC 1 is connected to the tie point of resistance R 13 and resistance R 14, between the anode of the photodiode in opto-coupler chip U1 and negative electrode, be connected a resistance R 12, in order to reduce to disturb, feedback is detected more accurate, the negative electrode of the photodiode in opto-coupler chip U1 is connected on the tie point of resistance R 13 and resistance R 14 by a capacitor C 12, a capacitor C 13 in parallel in resistance R 13, a resistance R 15 in parallel in resistance R 14.In feedback loop, having increased a reference source chip IC 1 can further increase the precision of feedback, promotes the operating efficiency of circuit.
Detailed introduction that the high accuracy protection circuit against input over-voltage of a kind of self-oscillation flyback converter above the utility model embodiment being provided is capable, applied specific case herein principle of the present utility model and execution mode are set forth, the explanation of above embodiment is just for helping to understand core concept of the present utility model; , for one of ordinary skill in the art, according to thought of the present utility model, all will change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model meanwhile.
Claims (6)
1. the high accuracy protection circuit against input over-voltage of self-oscillation flyback converter, comprise: transformer T1, metal-oxide-semiconductor and current-limiting resistance R9, voltage input end Vin+ passes through the primary coil of transformer T1 successively, the drain electrode of metal-oxide-semiconductor and source electrode, current-limiting resistance R9 ground connection, coupling energy on transformer T1 secondary coil is exported to voltage output end Vo through rectifying tube D2 and energy storage filter capacitor C10 successively, the also grid power supply to metal-oxide-semiconductor through a bleeder circuit of voltage input end Vin+, it is characterized in that, also comprise: with the ancillary coil T2 of transformer T1 coupling, positive-negative-positive triode Q2 and NPN type triode Q3, ancillary coil one end ground connection other end is connected to the grid of metal-oxide-semiconductor successively through a capacitor C 3 and resistance R 5, metal-oxide-semiconductor grid is successively through a resistance R 6, one resistance R 7, the collector and emitter ground connection of NPN type triode Q3, the described other end of ancillary coil connects the base stage of NPN type triode Q3 through a capacitor C 5, the base stage of NPN type triode Q3 connects the source electrode of metal-oxide-semiconductor by a resistance R 8, the emitter of positive-negative-positive triode connects the grid of metal-oxide-semiconductor, the collector electrode of positive-negative-positive triode connects the source electrode of metal-oxide-semiconductor, the base stage of positive-negative-positive triode Q2 is connected on the tie point of resistance R 6 and resistance R 7, between the source electrode of metal-oxide-semiconductor and NPN type triode Q3, be connected a capacitor C 6, voltage input end Vin+ is successively through a resistance R 1 and resistance R 101 ground connection, the grid of metal-oxide-semiconductor connects the cathode connection terminal of an a reference source chip, the anodic bonding end ground connection of this reference source chip, the base pressure link of this reference source chip is connected on the tie point of resistance R 1 and resistance R 101.
2. the high accuracy protection circuit against input over-voltage of self-oscillation flyback converter as claimed in claim 1, is characterized in that, a filter capacitor C101 in parallel in resistance R 1.
3. the high accuracy protection circuit against input over-voltage of self-oscillation flyback converter as claimed in claim 1 or 2; it is characterized in that; described bleeder circuit comprises: resistance R 2, resistance R 3 and the resistance R 4 of connecting successively; voltage input end Vin+ passes through resistance R 2, resistance R 3 and resistance R 4 ground connection successively, and the tie point of resistance R 3 and resistance R 4 is connected to the grid of metal-oxide-semiconductor.
4. the high accuracy protection circuit against input over-voltage of self-oscillation flyback converter as claimed in claim 1 or 2, is characterized in that, voltage input end Vin+ is through capacitor C 1 ground connection.
5. the high accuracy protection circuit against input over-voltage of self-oscillation flyback converter as claimed in claim 1 or 2, is characterized in that, energy storage filter capacitor C10 exports to voltage output end Vo through an inductance L 1.
6. the high accuracy protection circuit against input over-voltage of self-oscillation flyback converter as claimed in claim 1 or 2; it is characterized in that; also comprise an optocoupler feedback loop, optocoupler feedback loop detects the voltage on energy storage filter capacitor C10 and feeds back to the base stage of NPN type triode Q3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320687640.5U CN203536941U (en) | 2013-11-01 | 2013-11-01 | A high-definition input overvoltage protection circuit of a self-oscillation flyback converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320687640.5U CN203536941U (en) | 2013-11-01 | 2013-11-01 | A high-definition input overvoltage protection circuit of a self-oscillation flyback converter |
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| CN203536941U true CN203536941U (en) | 2014-04-09 |
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| CN201320687640.5U Expired - Lifetime CN203536941U (en) | 2013-11-01 | 2013-11-01 | A high-definition input overvoltage protection circuit of a self-oscillation flyback converter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116365902A (en) * | 2023-05-29 | 2023-06-30 | 深圳市英能达电子有限公司 | Switching power supply circuit topology |
-
2013
- 2013-11-01 CN CN201320687640.5U patent/CN203536941U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116365902A (en) * | 2023-05-29 | 2023-06-30 | 深圳市英能达电子有限公司 | Switching power supply circuit topology |
| CN116365902B (en) * | 2023-05-29 | 2023-08-11 | 深圳市英能达电子有限公司 | Switching power supply circuit topology |
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Granted publication date: 20140409 |
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