PHOTODIODE AMPLIFIER CIRCUIT Russian patent published in 2011 - IPC H03F17/00 

FIELD: physics.

SUBSTANCE: invention relates to photodetector amplifier devices and specifically to a photodiode amplifier device for a smoke fire detector. The amplifier (dwg.1) has a differential amplifier (DA) (2) with a voltage source (1), having a potential former (PF) (3) lying in the potential interval of the power supply Leads of the photodiode (4) are connected to inputs of the DA (2). There is a first and a second resistor (R) (5, 6). Thee first input of the DA (2) is connected to the PF (3) through the first R (5) and the second input of the DA (2) is connected to the PF (3) through the second R (6), where the first and second R (5, 6) assume different resistance values. For operation in pulsed mode (dwg.2), the leads of the photodiode (4) are connected to inputs DA (2) through capacitors (7) of having equal capacitance values, and the photodiode (4) is shunted by a resistor (8).

EFFECT: compensation for noise signal at the leads of the photodiode, which increases noise immunity of the smoke fire detector and reduces its cost due to non-use of screening.

2 cl, 2 dwg, 2 ex