| 摘要 |
Power extracted from an antenna inductively coupled to an alternating magnetic field is regulated to provide voltage supplies. In some implementations, a first voltage supply (e.g., 3.8 volts) provides regulated voltage to analog circuits and a second, lower, voltage supply (e.g., 1.4 volts) provides regulated voltage to digital circuits. The first voltage supply is regulated, using shunt regulation, by a first voltage regulator circuit. The second voltage supply is regulated, using a series regulation, by a second voltage regulator circuit. The second voltage regulator circuit is supplied by the shunted current from the first voltage regulator. Excess shunt current provided by the first regulator circuit can be bypassed (e.g., bypassed to ground). The second voltage regulator circuit can use a timer circuit to control the amount of charge transferred to a second voltage supply rail. The timer circuit can compensate for different currents from the first voltage regulator circuit. |
