Patent ID: 9035634
Filing Date: 2015-05-19
Classification: H02M,H05B,Y02B

Abstract:
1. A power supply for use in a load control device for controlling the amount of power delivered to an electrical load from an AC power source, the load control device operable to receive an AC voltage waveform of the AC power source, the power supply operable to generate a DC output voltage for powering a remote control device, the power supply comprising: an energy storage element across which the output voltage is generated, the energy storage element arranged to conduct an asymmetrical output current through the remote control device; a controllably conductive switching circuit coupled in series electrical connection with the energy storage element, the controllably conductive switching circuit configured to conduct a charging current from the AC power source through the energy storage element for charging the energy storage element to produce the output voltage, the controllably conductive switching circuit configured to switch to a conductive state after the magnitude of the AC voltage waveform exceeds approximately the magnitude of the DC voltage during a half-cycle of the AC voltage waveform; a threshold detect circuit configured to receive a first control signal representative of the magnitude of the output voltage and a second control signal representative of the amount of time that the energy storage element has been charging during the half-cycle; and a latching circuit coupled to the controllably conductive switching circuit and the threshold detect circuit, the latching circuit configured to cause the controllably conductive switching circuit to become non-conductive in response to the magnitude of the output voltage and the amount of time that the energy storage element has been charging during the half-cycle, resulting in the magnitude of the charging current conducted from the AC power source through the energy storage element being approximately the same each half-cycle.