Patent ID: 7250806

Claim:
A temperature compensated optically-coupled circuit, comprising: a current source light detection circuit configured for optical coupling to a light source providing an optical signal of a first pulse width, the light detection circuit further being configured to generate a light detection signal in response thereto, the light detection circuit having a first temperature coefficient associated therewith; a first operational amplifier circuit configured to receive the light detection signal and provide a first operational amplifier output signal; a temperature dependent reference current source circuit having a second temperature coefficient associated therewith and configured to generate a temperature dependent reference signal that varies in accordance with the second temperature coefficient; a second operational amplifier circuit configured to receive the temperature dependent reference signal at a first input thereof and the light detection signal at a second input thereof and provide a second operational amplifier output signal; a comparator circuit configured to receive the light detection signal and the first operational amplifier output signal as first inputs thereto, and the temperature dependent reference signal and the second operational amplifier output signal as second inputs thereto, the first and second temperature coefficients being substantially the same, the comparator circuit further being configured to provide a comparator output signal having a second pulse width substantially the same as the first pulse width.