Patent ID: 6208215
Filing Date: 2001-03-27
Classification: H03L

Abstract:
An apparatus for producing an output signal having a substantially constant frequency, the apparatus comprising:a voltage controlled oscillator configured to receive a control bias current signal and to produce a clock signal having a first frequency;a semiconductor workpiece having a thermal resistance and a thermal capacitance;a heat source positioned at a first point within the semiconductor workpiece, the heat source configured to receive the clock signal and generate a heat pulse in the semiconductor workpiece;a thermal network formed within the semiconductor workpiece and having a thermal time constant, the thermal network configured to receive the heat pulse and produce a voltage signal based upon the thermal time constant;a limiting amplifier configured to receive, amplify, and limit the voltage signal to produce a clipped output voltage; anda comparator configured to receive the clock signal and the clipped output voltage and produce the control bias current signal corresponding to a phase difference between the clock signal and the clipped output voltage, wherein the voltage controlled oscillator alters the first frequency of the clock signal in response to the control bias current signal.