Patent ID: 8878514

Claim:
A method to achieve an energy efficient switching DC-to-DC regulator, comprising the steps of: (1) providing a switching DC-to-DC regulator supplied by a battery, comprising an error amplifier having as inputs a reference voltage and an output voltage of the regulator, an inductor, an output capacitor, a high pass transistor connected to VDD voltage, a low pass transistor connected to ground, and a processing logic unit; (2) initiating a power-down request at the processing logic unit; (3) ramping down the reference voltage to 0 Volt such that the output voltage is ramped down to 0V by a regulator's switching regulation and a current through the inductor changes its direction and flows from a capacitor side to a battery's port in order to recharge the battery, wherein said ramping down the reference voltage is performed by an output of a digital-to-analog converter (DAC) and a DAC code is ramped down by the processing logic unit; and (4) shutting-off the regulator's switching regulation completely, when the reference voltage reaches 0V, and open the high pass transistor and close the low pass transistor to keep the output voltage at 0V.