VALLEY TO VALLEY SWITCHING IN QUASI-RESONANT MODE FOR DRIVER

摘要

Techniques are described to adjust the time when a switch is turned on from the time of one voltage valley to the time of another voltage valley for controlling an average load current or average load voltage. In some examples, the adjustment is instantaneous, and in some examples, the adjustment is gradual. Both of these example techniques provide for high switching efficiency of the switch.

主权项

1. A method for controlling power delivered to a load, the method comprising:
determining whether or not to adjust a turn-on time of a switch from a first time associated with a first voltage valley in an oscillating voltage at a node of the switch to a second time associated with a second voltage valley in the oscillating voltage at the node of the switch; determining one or more switch operational parameters for the switch such that if the turn-on time is adjusted from the first time to the second time an amount of power delivered to the load is substantially the same immediately before the adjustment and immediately after the adjustment; adjusting the turn-on time of the switch to the second time based on the determination to adjust the turn-on time; and setting the one or more switch operational parameters for the switch based on the determined one or more switch operational parameters.