Offset cancelling amplifier circuit having Miller integrator as offset detector

An optical receiver circuit comprising:

• a photodetector section responsive to an optical signal for converting the optical signal into an input current signal;
• a pre-amplifier section comprising at least one pre-amplifier responsive to the input current signal for converting the input current signal into an input voltage signal;
• a limiting amplifier having an input for amplifying the input voltage signal incoming through said input while preventing amplified amplitude from exceeding a predetermined level to provide an output signal;
• an offset detector comprising only one Miller integrator for detecting an offset in said output signal to produce a detection signal representing an offset amount detected;
• and
• an offset controller coupled between said input of said limiting amplifier and said detection signal of said offset detector for controlling said input of said limiting amplifier in response to said detection signal to reduce or cancel said offset in said output signal.

A polarity converter circuit for converting a unipolar input current pulse signal into a bipolar input voltage pulse signal, comprising:

• a pre-amplifier section including at least one pre-amplifier for converting the unipolar input current pulse signal into unipolar input voltage pulse signal;
• a limiting amplifier having an input for amplifying the unipolar input voltage pulse signal incoming through said input while preventing amplified amplitude from exceeding a predetermined level to produce an output signal of a bipolar voltage pulse signal;
• an offset detector comprising only one Miller integrator for detecting an offset in said output signal to produce a detection signal representative of the offset amount detected;
• and
• an offset controller coupled between said input of said limiting amplifier and said detection signal of said offset detector for controlling said input of said limiting amplifier in response to said detection signal reduce said offset in said output signal.

An optical receiver circuit comprising:

• a photodetector section responsive to an optical signal for converting the optical signal into a unipolar input current pulse signals;
• a pre-amplifier section comprising at least one pre-amplifier for converting the unipolar input current pulse signal into a unipolar input voltage pulse signal;
• a limiting amplifier having an input for amplifying the unipolar input voltage pulse signal incoming through said input while preventing amplified amplitude from exceeding a predetermined level to produce an output signal of a bipolar voltage pulse signal;
• an offset detector comprising only one Miller integrator for detecting an offset in said output signal to produce a detection signal representative of the offset amount detected;
• and
• an offset controller coupled between said input of said limiting amplifier and said detection signal of said offset detector for controlling said input of said limiting amplifier in response to said detection signal to reduce said offset in said output signal.