Ambient light suppression circuit for photodiode receiver applications

摘要

An optical receiver circuit that effectively suppresses ambient light. A photodiode receives both desired higher frequency modulated optical signals, as well as the lower frequency or even DC ambient light optical signals. The optical receiver circuit includes a trans-impedance amplifier as do conventional optical receiver circuits. However, the optical receiver circuit also includes an ambient light suppression circuit in a feedback loop between the output terminal of the trans-impedance amplifier and the input terminal of the trans-impedance amplifier. The transfer function of the ambient light suppression circuit may be selected such that the transfer function of the optical receiver circuit filters out DC and lower frequency components contributed by the unwanted ambient light, and passes the higher frequency components that correspond to the wanted optical signal that actually contains the information of interest.