Voltage regulation of near field communication communicators

摘要

A NFC enabled device to couple inductively to the H field of an RF signal and a regulator to regulate a voltage derived from an RF signal inductively coupled to the inductive coupler. The regulator has at least one voltage controlled impedance having a switch on voltage. A regulator controller provides a control voltage to each voltage controlled impedance such as that the control voltage is not less than the switch on voltage of the voltage controlled impedance.

主权项

1. A near field communications (NFC) enabled device, comprising:
a rectifier configured to rectify an output of an antenna circuit to provide a rectified output; and a regulator configured to regulate an output of the antenna circuit based upon the rectified output, the regulator comprising:
an amplifier configured to determine a difference between the rectified output and a reference voltage to provide a control signal, the amplifier comprising:
a differential transistor pair, wherein each transistor of the differential transistor pair configured to be a respective amplifier input,a first transistor and a second transistor configured to draw a bleed current,a first current mirror configured to couple the differential transistor pair to a voltage source;a second current mirror and a third current mirror respectively coupled to the first transistor and the second transistor; anda voltage setter configured to combine the bleed current with the control signal; anda plurality of voltage controlled impedances configured to regulate the output of the antenna circuit based upon an output of the voltage setter, wherein:the bleed current causes the plurality of voltage controlled impedances to be active; andeach of the plurality of voltage controlled impedances couples a respective output of an antenna circuit to ground.