| 摘要 |
PURPOSE: A circuit for sensing a center of a pulse is provided to detect accurately a center of a pulse having noise by using an analog differential circuit. CONSTITUTION: A switch control signal generator(22) is used for receiving an input signal(Sin) of a sensed pulse and generating switch control signals(P1,P2,P3,P4,P5,P6) according to the input signal(Sin) in order to control the first to the fourth controlled current sources(14,16,18,20) and the first and the second switches(28,30). The first controlled current source(14) has an input terminal connected with a voltage source(VCC) and an output terminal connected with a cathode input terminal of a comparator(12). The second controlled current source(16) has an input terminal connected with a cathode input terminal of a comparator(12) and an output terminal connected with a ground voltage(GND). The third controlled current source(18) has an input terminal connected with the voltage source(VCC) and an output terminal connected with an anode input terminal of a comparator(12). The fourth controlled current source(20) has an input terminal connected with the anode input terminal of the comparator(12) and an output terminal connected with the ground voltage(GND). The first switch(28) is used for connecting the cathode input terminal of the comparator(12) with a voltage source(Vreset) of a reset capacitor. The second switch(30) is used for connecting the anode input terminal of the comparator(12) with the voltage source(Vreset) of the reset capacitor. The comparator(12) outputs a pulse center signal(Sout) according to the positive input terminal and the cathode input terminal.
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