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CN-224205077-U - Commercial power synchronous conversion circuit

CN224205077UCN 224205077 UCN224205077 UCN 224205077UCN-224205077-U

Abstract

The utility model provides a mains supply synchronous conversion circuit which comprises an alternating current input interface, a square wave signal output interface, an isolation conversion circuit, an optical coupler isolation circuit, a voltage stabilizing control circuit and a synchronous square wave generating circuit, wherein a transformer, a large capacitor or a chip with high cost is not needed to be used in the circuits, the production cost is greatly reduced, high-low voltage electrical isolation is realized through the optical coupler isolation circuit, the system safety and the anti-interference capability are effectively improved, the isolation conversion circuit is used for suppressing noise and transient overvoltage through multiple filtering and TVS diodes, the design of limiting surge current is combined, the high stability of 12V direct current output is ensured, the voltage stabilizing control circuit and the synchronous square wave generating circuit are used for generating a 3.3V square wave signal which is strictly synchronous with the mains supply, the precision is improved, and meanwhile multiple protection mechanisms such as fuses, safety capacitors and the like are provided, and the reliability of the circuit is further improved.

Inventors

  • LIU JIA
  • XU MINGFEI
  • MA JINJING
  • PAN LEI

Assignees

  • 苏州思卡信息系统有限公司

Dates

Publication Date
20260505
Application Date
20250528

Claims (10)

  1. 1. The utility power synchronous conversion circuit is characterized by comprising an alternating current input interface, a square wave signal output interface, an isolation conversion circuit, an optical coupler isolation circuit, a voltage stabilizing control circuit and a synchronous square wave generating circuit, wherein the output end of the alternating current input circuit is respectively connected with the input end of the isolation conversion circuit and the input end of the optical coupler isolation circuit, the output end of the isolation conversion circuit is respectively connected with the output end of the optical coupler isolation circuit and the input end of the voltage stabilizing control circuit, the output end of the voltage stabilizing control circuit and the output end of the optical coupler isolation circuit are respectively connected with the input end of the synchronous square wave generating circuit, the output end of the synchronous square wave generating circuit is connected with the square wave signal output interface, the alternating current input circuit comprises an alternating current input port used for being connected with 220V commercial power, the isolation conversion circuit is used for converting 220V alternating current into 12V direct current and filtering high-frequency noise, the optical coupler isolation circuit is used for converting 220V alternating current into 12V square wave signals, the voltage stabilizing control circuit is used for generating a stable low-voltage direct current power supply, and the synchronous square wave generating circuit is used for converting 12V square wave signals into 3.3V square wave signals which are synchronous with the commercial power frequency.
  2. 2. The circuit of claim 1, wherein the AC input interface is an interface J2, the square wave signal output interface J3, the isolation conversion circuit comprises an isolation conversion unit U2, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C4, a fuse F1 and a TVS diode D3, the output end of the interface J2 is connected with the input end of the isolation conversion unit U2, the isolation conversion unit U2 is respectively connected with the output end of the optocoupler isolation circuit and the input end of the voltage stabilizing control circuit, the side edge of the isolation conversion unit U2 is connected with a capacitor C5 and a capacitor C6, the capacitor C5 is an energy storage capacitor, the capacitor C6 is a Y1 capacitor, the capacitor C5 and the capacitor C6 are used for suppressing common mode noise and stabilizing DC bus voltage, and the output end of the isolation conversion unit U2 is sequentially provided with a capacitor C7, a capacitor C8, a TVS diode D3, a capacitor C4, a capacitor C7 and a capacitor C8 and a capacitor C4, which play a role in filtering, and the TVS diode D3 plays a role in suppressing transient overvoltage.
  3. 3. The synchronous switching circuit of mains supply of claim 2, wherein a resistor R5 and an inductor L1 are further connected between the fuse F1 and the pin 1 of the isolation switching unit U2 in sequence, the resistor R5 limits surge current at the starting moment, the post-stage isolation switching unit U2 or the capacitor C5 and the capacitor C6 are prevented from being damaged by overcurrent, the inductor L1 performs filtering and energy storage, the voltage stability of a direct current side is ensured, and electromagnetic interference is restrained.
  4. 4. The synchronous switching circuit of mains supply of claim 2, wherein a capacitor C1 is further arranged between the 1 pin and the 2 pin of the isolation switching unit U2, and the capacitor C1 is a safety capacitor and plays a role of filtering.
  5. 5. The utility power synchronous conversion circuit of claim 1, wherein the optocoupler isolation circuit comprises a photoelectric coupler U3, a resistor R75, a resistor R76 and a resistor R77, wherein the output end of the alternating current input circuit is connected with the input end of the photoelectric coupler U3, the output end of the photoelectric coupler U3 is connected with the input end of the synchronous square wave generating circuit, the output end of the alternating current input circuit is connected with the 5 pin of the photoelectric coupler U3, the resistor R77 plays a role of boosting, a resistor R75 is connected between the 1 pin of the interface J2 and the 1 pin of the photoelectric coupler U3, the resistor R75 plays a role of dividing voltage, a resistor R76 is arranged between the 1 pin and the 2 pin of the photoelectric coupler U3, and the resistor R76 plays a role of ensuring that the voltage of the 1 pin and the 2 pin of the U3 does not exceed the rated value of the resistor R76.
  6. 6. The utility power synchronous conversion circuit of claim 1, wherein the voltage stabilizing control circuit comprises a three-terminal voltage stabilizing unit U4, a resistor R78, a resistor R79 and a resistor R80, the output end of the alternating current input circuit is connected with the three-terminal voltage stabilizing unit U4, the output end of the three-terminal voltage stabilizing unit U4 is connected with the input end of the synchronous square wave generating circuit, the three-terminal voltage stabilizing unit U4 is connected with the resistor R78, the resistor R80, the resistor R79, the resistor R78 and the resistor R80 form a voltage dividing network and are matched with the three-terminal voltage stabilizing unit U4 to provide reference voltage, and the resistor R79 plays a role of limiting current to ensure the stability of signal transmission.
  7. 7. The circuit of claim 1, wherein the synchronous square wave generating circuit comprises an NPN diode Q12, a resistor R71, a resistor R73 and a resistor R74, wherein the output end of the optocoupler isolation circuit is connected with the base electrode of the triode Q12 through the resistor R73, the resistor R74 between the base electrode and the emitter electrode of the triode Q12 is a base bias resistor for setting the conduction threshold of the Q12 and limiting the base current, overdrive is prevented, the resistor R74 is a pull-up resistor, the emitter electrode of the triode Q12 is grounded, and the collector electrode of the triode Q12 is respectively connected with the resistor R71 and the square wave signal output interface J3.
  8. 8. The synchronous switching circuit of mains supply of claim 7, wherein a TVS diode D27 is further connected between the output end of the optocoupler isolation circuit and the resistor R73 for protecting the latter circuit from a surge or voltage spike on the mains supply side.
  9. 9. The circuit of claim 6, wherein the three-terminal voltage regulator U4 has a specification TL431.
  10. 10. The circuit of claim 2, wherein the specification of the isolated converting unit U2 is LS03-13B12R3.

Description

Commercial power synchronous conversion circuit Technical Field The utility model relates to the technical field of circuits, in particular to a mains supply synchronous conversion circuit. Background In the related art, due to the influence of various factors, the commercial power voltage is variable and fluctuant, even distorted, and due to the change of the commercial power voltage, when the commercial power is connected into the vehicle type recognition device, a camera in the recognition device is easy to trigger stroboscopic effect due to unstable commercial power voltage, so that the commercial power is required to be converted into a stable square wave signal to be further used with the vehicle type recognition device in an adapting way. The existing commercial power conversion circuit mostly adopts the following measures to realize the conversion function: (1) The switching power supply is matched with a large capacitor and a transformer to realize the conversion function. (2) The conversion function is realized by using a chip, i.e., a BM1Z002FJ chip and a BM2P129T chip, as shown in FIG. 1. In the implementation manner, the scheme (1) has the defect of heavy volume, and the scheme (2) relies on a chip, so that the chip cost is high, the peripheral circuit of the chip is complex, and the production cost is further improved. In view of the above, the utility model provides a synchronous converting circuit for commercial power, which has small volume and low production cost. Disclosure of utility model The utility model aims to provide a commercial power synchronous conversion circuit which is small in size and low in production cost. The utility power synchronous conversion circuit is characterized by comprising an alternating current input interface, a square wave signal output interface, an isolation conversion circuit, an optical coupler isolation circuit, a voltage stabilizing control circuit and a synchronous square wave generating circuit, wherein the output end of the alternating current input circuit is respectively connected with the input end of the isolation conversion circuit and the input end of the optical coupler isolation circuit, the output end of the isolation conversion circuit is respectively connected with the output end of the optical coupler isolation circuit and the input end of the voltage stabilizing control circuit, the output end of the voltage stabilizing control circuit and the output end of the optical coupler isolation circuit are respectively connected with the input end of the synchronous square wave generating circuit, the output end of the synchronous square wave generating circuit is connected with the square wave signal output interface, the alternating current input circuit comprises an alternating current input port used for being connected with 220V commercial power, the isolation conversion circuit is used for converting 220V alternating current into 12V direct current and filtering high-frequency noise, the optical coupler isolation circuit is used for converting 220V alternating current into 12V square wave signals, the voltage stabilizing control circuit is used for generating a stable low-voltage direct current power supply, and the synchronous square wave generating circuit is used for converting 12V square wave signals into 3.3V square wave signals which are synchronous with the commercial power frequency. In some embodiments, the ac input interface is an interface J2, the square wave signal outputs an interface J3, the isolation transformation circuit includes an isolation transformation unit U2, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C4, a fuse F1, and a TVS diode D3, the output end of the interface J2 is connected to the input end of the isolation transformation unit U2, the isolation transformation unit U2 is respectively connected to the output end of the optocoupler isolation circuit and the input end of the voltage stabilizing control circuit, the side edge of the isolation transformation unit U2 is connected to a capacitor C5 and a capacitor C6, the capacitor C5 is an energy storage capacitor, the capacitor C6 is a Y1 capacitor, the capacitor C5 and the capacitor C6 are used for suppressing common mode noise and stabilizing dc bus voltage, the output end of the isolation transformation unit U2 is sequentially provided with a capacitor C7, a capacitor C8, a TVS diode D3, a capacitor C4, a capacitor C7, a capacitor C8, and a capacitor C4 all play a role in filtering, and the TVS diode D3 plays a role in suppressing overvoltage transients. Further, a resistor R5 and an inductor L1 are further connected between the fuse F1 and the pin 1 of the isolation conversion unit U2 in sequence, the resistor R5 limits the surge current at the moment of starting up, the post-isolation conversion unit U2 or the capacitor C5 and the capacitor C6 are prevented from being damaged by overcurrent, the inductor L1 performs filteri