APD (avalanche photo diode) voltage control circuit and method

APD (avalanche photo diode) voltage control circuit and method

  • CN 102,255,505 B
  • Filed: 07/29/2011
  • Issued: 03/18/2015
  • Est. Priority Date: 07/29/2011
  • Status: Active Grant
First Claim
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1. an APD voltage control circuit, comprises micro-control circuit and booster circuit,Described micro-control circuit, for controlling booster circuit, rises according to feedback signal control voltage, makes booster circuit boosted voltage as requested, finally reach APD operating voltage;

  • Booster circuit comprises boost chip and voltage-multiplying circuit;

    Described boost chip receives the control signal of micro-control circuit and the feedback signal of booster circuit, according to the control work of micro-control circuit;

    Described voltage-multiplying circuit carries out multiplication of voltage to the output voltage of boost chip;

    Described booster circuit adopts DC/DC conversion to realize, described booster circuit comprises switching transistor VT, diode VD, energy storage inductor L and output filter capacitor C, described booster circuit changes output voltage by the duty ratio changing switching transistor VT input pulse, and described voltage-multiplying circuit comprises rectifier diode and electric capacity;

    It is characterized in that, the shutoff pin of boost chip is by resistive pull-downs ground connection, and one of micro-control circuit exports and is connected with the shutoff pin of boost chip;

    The concrete rate-determining steps of described micro-control circuit is;

    power input voltage, and be low-voltage because boost chip turns off pin, APD voltage is in off state;

    Now micro-control circuit Loading Control program, just search the operating voltage of corresponding boost chip after having loaded in a lookup table, and APD voltage steps and the minimum control voltage of APD are set according to the information loaded, export high level control logic, output is opened, opens boost chip and start working;

    From the minimum control voltage of APD, micro-control circuit progressively increases APD control voltage according to stepping, if APD control voltage is less than operating voltage, just wait for 10us, then continue to increase APD control voltage, until APD control voltage equals APD operating voltage, input voltage is by boosting and the high pressure exporting APD needs after voltage-multiplying circuit.

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