Reducing emissions in a near field communications (NFC) capable device

摘要

A near field communications (NFC) device is disclosed that interacts with other NFC devices to exchange information and/or the data. Another NFC device inductively couples a received communications signal onto an antenna circuit of the NFC device to provide a recovered communications signal. An overvoltage protection module regulates a power level of the recovered communication signal by detuning the antenna circuit when the power level of the recovered communication signal may cause damage the NFC device. Active components of the overvoltage protection module, such as voltage controlled impedances, operate in their linear mode of operation to reduce unwanted emissions during this regulation process.

主权项

1. A near field communications (NFC) device, comprising:
an antenna circuit configured to receive a communications signal to provide a recovered communications signal, the antenna circuit being tuned to receive the communications signal; and near field operational components configured to recover information from the recovered communications signal, the near field operational components comprising:
a rectifier configured to rectify the recovered communications signal to provide a rectified output; anda regulator configured to detune the antenna circuit to regulate a power level of the recovered communications signal when the rectified output is greater than a reference voltage.