CN205583764U - Input voltage undervoltage protection circuit of charger - Google Patents
Input voltage undervoltage protection circuit of charger Download PDFInfo
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- CN205583764U CN205583764U CN201620339847.7U CN201620339847U CN205583764U CN 205583764 U CN205583764 U CN 205583764U CN 201620339847 U CN201620339847 U CN 201620339847U CN 205583764 U CN205583764 U CN 205583764U
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Abstract
The utility model discloses an input voltage undervoltage protection circuit of charger, include the charger circuit who is connected with AC input, and with the PWM control circuit that charger circuit connects, still include diode D1 and diode D2, diode D1's positive pole connects the NULL L end, diode D2's positive pole connects the NULL N end, diode D1 and diode D2's negative pole links to each other and loops through resistance R1 and resistance R2 ground connection, still include the comparator, the negative pole input of comparator is connected resistance R1 and resistance R2's node, the positive input terminal of comparator and the resistance R3 of series connection and resistance R4's nodal connection, another termination power end VDD of resistance R3, resistance R4's other end ground connection. The utility model discloses charger high problem of charger fault rate under the grid voltage condition low has excessively effectively been solved.
Description
Technical field
This utility model relates to the under-voltage protecting circuit of the input voltage of a kind of charger.
Background technology
Along with the use environment of developing rapidly of electron trade, charger or Switching Power Supply becomes increasingly complex, many chargers or Switching Power Supply are applied in the severe place of power grid environment, and the height of line voltage has the biggest relation with the length of winding displacement, thickness and network load.Most chargers does not has input undervoltage to protect.When line voltage low to certain degree time, the fault rate of charger or Switching Power Supply can improve the biggest.
Utility model content
This utility model purpose is the under-voltage protecting circuit of input voltage that the defect existed for prior art provides a kind of charger, when line voltage low to certain degree time, charger can enter protected mode, thus avoid fault.
This utility model for achieving the above object, adopts the following technical scheme that the input voltage under-voltage protection circuit of a kind of charger, including the charger circuit being connected with ac input end, and the pwm control circuit being connected with described charger circuit；It is characterized in that, also including that diode D1 and diode D2, the anode of described diode D1 connect exchange input L end, the anode of described diode D2 connects exchange input N end；The negative electrode of described diode D1 and diode D2 is connected and passes sequentially through resistance R1 and resistance R2 ground connection；Also including comparator, the negative input of described comparator connects described resistance R1 and the node of resistance R2；The electrode input end of described comparator is connected with the node of the resistance R3 and resistance R4 of series connection, another termination power end VDD of described resistance R3, the other end ground connection of described resistance R4；The outfan of described comparator passes sequentially through diode D3 and resistance R5 and is connected with the base stage of PNP triode Q, it is provided with resistance R6 between emitter stage and the base stage of described PNP triode Q, the emitter stage of described PNP triode Q is connected with power end VDD, and the colelctor electrode of described PNP triode Q is connected with the VDD pin of PWM chip in described pwm control circuit.
The beneficial effects of the utility model: this utility model compares charger or the Switching Power Supply of traditional univoltage input, efficiently solve charger in the case of line voltage is too low, the problem that battery charger failure rate is high.Line voltage is too low, and charger then enters guard mode, and line voltage recovers normal, then charger is resumed work.
Accompanying drawing explanation
Fig. 1 is circuit theory schematic diagram of the present utility model.
Detailed description of the invention
Shown in Fig. 1, relate to the input voltage under-voltage protection circuit of a kind of charger, including the charger circuit 1 being connected with ac input end, and the pwm control circuit 2 being connected with described charger circuit 1；Also including that diode D1 and diode D2, the anode of described diode D1 connect exchange input L end, the anode of described diode D2 connects exchange input N end；The negative electrode of described diode D1 and diode D2 is connected and passes sequentially through resistance R1 and resistance R2 ground connection；Also including comparator, the negative input of described comparator connects described resistance R1 and the node of resistance R2；The electrode input end of described comparator 3 is connected with the node of the resistance R3 of series connection and resistance R4, another termination power end VDD of described resistance R3, the other end ground connection of described resistance R4；The outfan of described comparator 3 passes sequentially through diode D3 and resistance R5 and is connected with the base stage of PNP triode Q, it is provided with resistance R6 between emitter stage and the base stage of described PNP triode Q, the emitter stage of described PNP triode Q is connected with power end VDD, and the colelctor electrode of described PNP triode Q is connected with the VDD pin of PWM chip in described pwm control circuit 2.
Operation principle is: L, N voltage is after diode D1 and diode D2 carries out halfwave rectifier, and a DC voltage by the time, voltage=Vin*0.9, this DC voltage samples to the input negative pole of comparator 3 after resistance R1 with resistance R2 dividing potential drop.After resistance R3 and resistance R4 carries out dividing potential drop to power vd D, it is provided that inputting one reference voltage of positive pole to comparator 3, diode D3 is to isolate to do the output of comparator 3.Resistance R5, resistance R6 and audion Q form amplifying circuit.
When input voltage is too low; the input cathode voltage of comparator 3 reduces; the input cathode voltage of comparator 3 is less than input cathode voltage; comparator 3 is output as high level; audion Q enters cut-off state; the VDD foot of the PWM chip in pwm control circuit 2 does not has voltage, and charger can not work, and enters under-voltage protection state.
The foregoing is only preferred embodiment of the present utility model, not in order to limit this utility model, all within spirit of the present utility model and principle, any modification, equivalent substitution and improvement etc. made, within should be included in protection domain of the present utility model.
Claims (1)
1. the input voltage under-voltage protection circuit of a charger, it is characterised in that include and ac input end
The charger circuit connected, and the pwm control circuit being connected with described charger circuit；It is characterized in that,
Also include that diode D1 and diode D2, the anode of described diode D1 connect exchange input L end, described diode
The anode of D2 connects exchange input N end；The negative electrode of described diode D1 and diode D2 is connected and passes sequentially through resistance
R1 and resistance R2 ground connection；Also including comparator, the negative input of described comparator connects described resistance R1 and electricity
The node of resistance R2；The electrode input end of described comparator is connected with the node of the resistance R3 and resistance R4 of series connection, institute
State another termination power end VDD of resistance R3, the other end ground connection of described resistance R4；The output of described comparator
End passes sequentially through diode D3 and resistance R5 and is connected with the base stage of PNP triode Q, the transmitting of described PNP triode Q
Being provided with resistance R6 between pole and base stage, the emitter stage of described PNP triode Q is connected with power end VDD, described
The colelctor electrode of PNP triode Q is connected with the VDD pin of PWM chip in described pwm control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620339847.7U CN205583764U (en) | 2016-04-21 | 2016-04-21 | Input voltage undervoltage protection circuit of charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620339847.7U CN205583764U (en) | 2016-04-21 | 2016-04-21 | Input voltage undervoltage protection circuit of charger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205583764U true CN205583764U (en) | 2016-09-14 |
Family
ID=56859897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620339847.7U Active CN205583764U (en) | 2016-04-21 | 2016-04-21 | Input voltage undervoltage protection circuit of charger |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205583764U (en) |
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2016
- 2016-04-21 CN CN201620339847.7U patent/CN205583764U/en active Active
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |