RF power detector and detection method

摘要

The invention provides an RF detection circuit and method using an envelope detector having an output connected to a first input of a differential amplifier and a reference storage capacitor to a second input of the differential amplifier. In a preferred implementation of the calibration mode, there is initial discharging of a reference storage capacitor, high speed charging of the reference storage capacitor until the differential amplifier output toggles, then slower discharging of the reference storage capacitor until the differential amplifier output toggles again. The resulting voltage is stored on the reference storage capacitor for use in a subsequent detection mode. This provides storage of an offset voltage which calibrates both the envelope detector differential amplifier functions.

主权项

1. An RF detector circuit, comprising:
an envelope detector having an output capacitor on which an envelope detection signal is provided; a reference storage capacitor for storing a reference voltage; a differential amplifier having a first input coupled to the output capacitor and a second input coupled to the reference storage capacitor; a reset circuit; a charging circuit for charging the reference storage capacitor at a first rate; and a discharge circuit for discharging the reference storage capacitor at a second, different, rate; and a controller, for controlling the sequence of charging and discharging the reference storage capacitor to store an amplifier offset voltage on the reference storage capacitor based on toggling of the amplifier output during the charging or discharging operation which has the slower rate.