Multi-stage power supply for a load control device having a low-power mode

摘要

A multi-stage power supply for a load control device is able to operate in a low-power mode in which the power supply has a decreased power consumption when an electrical load controlled by the load control device is off. The load control device comprises a load control circuit and a controller, which operate to control the amount of power delivered to the load. The power supply comprises a first efficient power supply (e.g., a switching power supply) operable to generate a first DC supply voltage. The power supply further comprises a second inefficient power supply (e.g., a linear power supply) operable to receive the first DC supply voltage and to generate a second DC supply voltage for powering the controller. The controller controls the multistage power supply to the low-power mode when the electrical load is off, such that the magnitude of the first DC supply voltage decreases to a decreased magnitude and the inefficient power supply continues to generate the second DC supply voltage.