CN201243197Y - Protection circuit for short circuit of module power supply - Google Patents
Protection circuit for short circuit of module power supply Download PDFInfo
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- CN201243197Y CN201243197Y CNU2008201089991U CN200820108999U CN201243197Y CN 201243197 Y CN201243197 Y CN 201243197Y CN U2008201089991 U CNU2008201089991 U CN U2008201089991U CN 200820108999 U CN200820108999 U CN 200820108999U CN 201243197 Y CN201243197 Y CN 201243197Y
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Abstract
The utility model provides a module power short-circuit protective circuit which is used between a pulse-width modulation control chip and a transformer. The short-circuit protective circuit comprises an opto-coupler device, a first resistance, a second resistance and a capacitance; wherein, one end of the capacitance is grounded, the other end thereof is connected to CS2 end of the pulse-width modulation control chip, the C end of the opto-coupler device is connected with COMP end of the pulse-width modulation control chip, the E end is grounded; one end of the first resistance is connected with the C end of the opto-coupler device, and the other end thereof is connected with the second resistance which is connected with the E end of the opto-coupler device. The module power short-circuit protective circuit can solve the technical problems that the output short circuit of the module power supply easily damages the power supply, and the structure of the circuit is simple, the cost is low, and debugging is easy. By adopting the short-circuit protective circuit, the module power supply can in a short circuit for a long time when in the condition of no-loading; when the short circuit disappears, the module power supply can be automatically restored.
Description
Technical field
The utility model relates to a kind of short-circuit protection circuit that is used for modular power source, belongs to the switch power technology field.
Background technology
Switching Power Supply has advantages such as high efficiency, small size, is representing the developing direction of stabilized voltage power supply.Along with continuous advancement in technology, Switching Power Supply develops to modular direction day by day.Adopt the Switching Power Supply (abbreviation modular power source) of modularized design to have short, characteristics such as reliability is high, system upgrade is easy of design cycle, it is used more and more widely.
Existing modular power source generally adopts PWM (pulse-width modulation) technology, has therefore occurred the pwm chip of a lot of special uses on the market, for example voltage mode active clamp transform controller LM5025, current mode pwm signal generator 3843 etc.Wherein LM5025 is the 100V PDM keyer that is used for positive excitation converter, has the effective clamper/reset technique that is used in the distributed power source structure.This new PWM control chip is operated in high switching frequency, than being used in communication, automotive electronics, common normal shock adjuster distributed and industrial power system and multi-output power supply usually higher efficient and bigger power density is arranged.
For the LM5025 in the modular power source can effectively be worked, need provide special short-circuit protection scheme for it.At present, short-circuit protection scheme commonly used adopts " beat and cough up " formula (hiccup) protection more, and its circuit theory as shown in Figure 1.This short-circuit protection scheme is to utilize the current transformer sampled signal to deliver to the CS2 pin of LM5025, and when the voltage of CS2 pin was higher than 0.25V, overcurrent protection was moved, and reduced the output duty cycle of OUT pin significantly, made LM5025 be in " beat and cough up " state.Under this guard mode.Power supply several switch periods of only working enter start-up course for a long time then, and average power consumption is low, even long-time output short-circuit also can not cause the cause thermal damage of power supply.
But above-mentioned short-circuit protection scheme at LM5025 need be at the more peripheral components of chip arranged around, and implementation cost is higher.On the other hand, this short-circuit protection scheme busy line plate area is too big, can't be suitable for for the small-sized module power supply.
Summary of the invention
The purpose of this utility model is to provide a kind of new module power supply short-circuit protective circuit.This short-circuit protection circuit especially is fit to and pulse width modulation controlled chip LM5025 cooperatively interacts carries out work.
For realizing above-mentioned purpose, the utility model adopts following technical scheme:
A kind of module power supply short-circuit protective circuit is used between pulse width modulation controlled chip and the transformer, it is characterized in that:
Described module power supply short-circuit protective circuit comprises optocoupler, first resistance, second resistance and electric capacity;
Wherein, an end ground connection of described electric capacity, the other end is connected on the CS2 end of described pulse width modulation controlled chip, and the C end of described optocoupler connects the COMP end of described pulse width modulation controlled chip, and E holds ground connection;
One end of described first resistance connects the C end of described optocoupler, and the other end is connected with described second resistance, and described second resistance connects the E end of described optocoupler.
Has sampling resistor between the link of described first resistance and described second resistance and the CS2 of the described pulse width modulation controlled chip end.
Described pulse width modulation controlled chip is LM5025.
Module power supply short-circuit protective circuit provided by the utility model can solve the technical barrier that the modular power source output short-circuit damages power supply easily, and circuit structure is simple, with low cost, easily debugging.Utilize this short-circuit protection circuit, can make modular power source long-time short circuit under fully loaded situation, modular power source can recover automatically after short circuit disappears.
Description of drawings
Below in conjunction with the drawings and specific embodiments the utility model is further described.
Fig. 1 is a kind of circuit theory diagrams of existing module power supply short-circuit protective scheme;
Fig. 2 is the schematic diagram of module power supply short-circuit protective circuit provided by the utility model.
Embodiment
Referring to shown in Figure 2, this module power supply short-circuit protective circuit is by optocoupler V1, compositions such as resistance R 1, R2 and capacitor C 10.Wherein, the end ground connection of capacitor C 1O, other one terminates at the CS2 end of LM5025 chip.The C end of optocoupler V1 connects the COMP end of LM5025 chip, and E holds ground connection.Between the C of optocoupler end and E end is the resistance R 1 and the R2 of series connection, and wherein resistance R 1 connects the C end, and resistance R 2 connects the E end.Between the CS2 of the junction of R1 and R2 and LM5025 chip end, has a sampling resistor.
In order to satisfy the specification requirement of short-circuit protection, the resistance of resistance R 1 should be no more than 19 times of resistance R 2 resistances, and for example the R1 resistance is 1800 ohm, and the resistance of R2 is 100 ohm.Optocoupler V1 can adopt conventional device, as TLP521-1, PC817,6N137 etc.
The operation principle of this module power supply short-circuit protective circuit is such: when output short-circuit appearred in modular power source, output voltage dropped to zero volt, corresponding zero volt of also reducing to of the voltage of other winding induction of main transformer.At this moment, the supply power voltage of optocoupler V1 also is zero volt, therefore not conducting.The C of optocoupler V1, E present high-impedance state between the two ends, and the electrical level rising of the COMP end of LM5025 chip because the resistance value ratio of resistance R 1 and R2 is not more than 19, therefore surpasses 0.25V via the voltage of delivering to CS2 after resistance R 1 and the R2 dividing potential drop to 5V.According to the technical characterstic of LM5025 chip, this moment, LM5025 was in " beat and cough up " (hiccup) state, thereby had realized the short-circuit protection to modular power source.
Above this module power supply short-circuit protective circuit is had been described in detail.Needing ben is that this short-circuit protection circuit is not only applicable to adopt the modular power source of LM5025 chip, equally goes for adopting in the modular power source of other current mode pwm chips as 3843 grades yet.Therefore, for one of ordinary skill in the art, any conspicuous change of under the prerequisite that does not deviate from the utility model connotation it being done all will constitute to the utility model infringement of patent right, with corresponding legal responsibilities.
Claims (4)
1. a module power supply short-circuit protective circuit is used between pulse width modulation controlled chip and the transformer, it is characterized in that:
Described module power supply short-circuit protective circuit comprises optocoupler, first resistance, second resistance and electric capacity;
Wherein, an end ground connection of described electric capacity, the other end is connected on the CS2 end of described pulse width modulation controlled chip, and the C end of described optocoupler connects the COMP end of described pulse width modulation controlled chip, and E holds ground connection;
One end of described first resistance connects the C end of described optocoupler, and the other end is connected with described second resistance, and described second resistance connects the E end of described optocoupler.
2. module power supply short-circuit protective circuit as claimed in claim 1 is characterized in that:
Has sampling resistor between the link of described first resistance and described second resistance and the CS2 of the described pulse width modulation controlled chip end.
3. module power supply short-circuit protective circuit as claimed in claim 1 is characterized in that:
Described pulse width modulation controlled chip is LM5025.
4. module power supply short-circuit protective circuit as claimed in claim 3 is characterized in that:
The resistance of described first resistance is no more than 19 times of described second resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201089991U CN201243197Y (en) | 2008-07-02 | 2008-07-02 | Protection circuit for short circuit of module power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201089991U CN201243197Y (en) | 2008-07-02 | 2008-07-02 | Protection circuit for short circuit of module power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201243197Y true CN201243197Y (en) | 2009-05-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201089991U Expired - Fee Related CN201243197Y (en) | 2008-07-02 | 2008-07-02 | Protection circuit for short circuit of module power supply |
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| CN (1) | CN201243197Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104184104B (en) * | 2013-05-27 | 2017-11-24 | 深圳市海洋王照明工程有限公司 | A kind of overcurrent protection automatic restoring circuit |
-
2008
- 2008-07-02 CN CNU2008201089991U patent/CN201243197Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104184104B (en) * | 2013-05-27 | 2017-11-24 | 深圳市海洋王照明工程有限公司 | A kind of overcurrent protection automatic restoring circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: BEIJING TONLIER ENERGY TECHNOLOGY CO., LTD. Free format text: FORMER NAME: TONLIER ENERGY TECHNOLOGY (BEIJING) CO., LTD. |
|
| CP01 | Change in the name or title of a patent holder |
Address after: 101111 Beijing City Economic and Technological Development Zone Branch fourteen Street No. nine Patentee after: Beijing Tonlier Energy-saving LLC. Address before: 101111 Beijing City Economic and Technological Development Zone Branch fourteen Street No. nine Patentee before: Tonlier Energy Technology(Beijing)Co.,Ltd. |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090520 Termination date: 20140702 |
|
| EXPY | Termination of patent right or utility model |