Air core gauge method and apparatus with reduced power dissipation

An apparatus to which a parameter signal indicative of a measure of a parameter is coupled, comprising:

• a delay circuit comprising means for receiving the parameter signal and providing a delayed signal in response thereto;
• a comparison circuit, coupled to the delay circuit and also receiving the parameter signal, comprising means for comparing the delayed signal to the parameter signal and for providing a comparison result signal characterized by a first signal condition if the delayed signal equals the parameter signal and a second condition if the delayed signal is different from the parameter signal;
• a chopper circuit, coupled to the comparison circuit, comprising means for receiving the comparison result signal and for providing a chopper output signal responsive thereto, the chopper output signal having a first duty cycle if the comparison result signal is characterized by the first signal condition and the chopper output signal having a second duty cycle if the comparison result is characterized by the second signal condition, the second duty cycle being greater than the first duty cycle;
• and
• means responsive to the parameter signal and the chopper output signal for providing a drive signal to drive a gauge to indicate the measure of the parameter, the drive signal having a first power level when the chopper output signal has the first duty cycle and having a second power level when the chopper output signal has the second duty cycle, the second power level being greater than the first power level.