Patent ID: 6034558
Filing Date: 2000-03-07
Classification: H03K,H03L

Abstract:
An apparatus for compensating for thermal drift of a first output signal (OUT1) produced by a logic circuit in response to an input signal (INPUT) after a first temperature dependent delay, the apparatus comprising:a first delay circuit for receiving and delaying said first output signal with a first variable delay to produce a second output signal (OUT2), the first variable delay being controlled by a value of a digital control signal (CONTROL) provided as input to said first variable delay circuit;an oscillator for generating an oscillator output signal (OSC.sub.-- OUT) having a period controlled by said value of said digital control signal, the oscillator output signal period being substantially proportional to a sum of said first temperature dependent delay and said first variable delay; and means for continually monitoring the oscillator output signal period and adjusting said value of said digital control signal so that said oscillator output signal period remains substantially constant,wherein said oscillator comprisesa second delay circuit for receiving and delaying an oscillator input signal (OSC.sub.-- IN) with a second variable delay to produce an oscillator output signal, the second variable delay being controlled by said value of said digital control signal provided as input to said second variable delay circuit, anda third delay circuit for receiving and delaying said oscillator output signal to produce said oscillator input signal with a second temperature dependent delay substantially similar to said first temperature dependent delay.