TEMPERATURE COMPENSATED APD DETECTOR BIAS AND TRANSIMPEDANCE AMPLIFIER CIRCUITRY FOR LASER RANGE FINDERS

摘要

Laser range finder circuitry (FIG. 1) including an avalanchephotodiode detector (315), a capacitor (C1) for storing a detector bias voltage,and a transimpedance amplifier (317) for amplifying the detector signal. Thecapacitor (C1) is charged in response to a first control signal (Iup) by a circuitemploying first and second field effect transistors (Qb1, Qb2) and is dischargedin response to a second control signal (IDN) by a circuit employing a third fieldeffect transistor (Qb4). An overload protection circuit including a single diode(CR3) is provided to accommodate excessive charge created by backscatterupon initial laser firing. A temperature sensor (319) is provided to develop atemperature signal which may be monitored to adjust the detector bias voltageand other parameters so as to permit use of an associated laser range finderover a wide range of temperatures.