NEAR FIELD RF COMMUNICATOR AND TIMING APPARATUS

摘要

A near field communications (NFC) device is disclosed that detects an envelope of a radio frequency (RF) signal. The NFC device includes a peak detector that determines the envelope of the RF signal. The peak detector compares a first differential signal voltage to a second differential signal voltage. The peak detector delays a rising edge of a first differential signal and provides the first differential signal voltage to the peak detector output when the first differential signal voltage is greater than the second differential signal voltage. The peak detector delays a falling edge of a second differential signal and provides the second differential signal voltage to the peak detector output when the second differential signal voltage is greater than the first differential signal voltage.

主权项

1. A peak detector for a near field communications (NFC) device, the peak detector comprising:
a delay line configured to delay a clock signal to provide a delayed clock signal; and a phase comparer configured to provide a control signal to the delay line based on a comparison of the clock signal and the delayed clock signal, the control signal being configured to adjust a delay of the delay line based on voltage level change of the clock signal.