Patent ID: 7228114

Claim:
A power detection circuit, comprising: a detector coupled to a source signal, wherein the detector is configured to produce a detector signal with a magnitude relative to the source signal; a plurality of amplifiers coupled to the detector, wherein each amplifier receives the detector signal and has an associated gain and an output signal proportional to the detector signal, the associated gain of at least two amplifiers being different; a switch having input terminals, each input terminal coupled to receive the output signal of a respective one of the plurality of amplifiers, and an output terminal for providing a switch output signal; an analog-to-digital converter (ADC) having an input terminal coupled to receive the switch output signal and being operative to generate an ADC output signal based on the switch output signal, the switch being controllable to switch the switch output signal from the output signal of an amplifier with higher gain to the output signal of an amplifier with lower gain when the detector signal goes above a first threshold, the first threshold determined to substantially avoid saturation of the ADC, and to switch the switch output signal from the output signal of an amplifier with lower gain to the output signal of an amplifier with higher gain when the detector signal goes below a second threshold, the second threshold determined to increase the rate of change of the switch output signal, the first threshold being higher than the second threshold; and logic for using the ADC output signal to detect a power level of the source signal.