Method and apparatus for turning on a lighting device

摘要

Aspects of the disclosure provide a method. The method includes regulating a time for turning on a switch to transfer energy via a transformer in a first control mode, determining a turn-on time for a second control mode based on the regulated time in the first control mode, and controlling the switch based on the determined turn-on time in the second control mode to transfer energy via the transformer.

主权项

1. A method, comprising:
regulating a time for turning on a switch to transfer energy via a transformer in a first control mode; determining a first turn-on time for the switch in the first control mode based on the regulated time in the first control mode; generating a count per a cycle, based on a clock signal in response to pulses in a pulse width modulation (PWM) signal that controls the switch; searching a minimum counted value among counts generated over a plurality of cycles; determining whether a dimmer is coupled with the switch or not; determining a second turn-on time for the switch in a second control mode based on the searched minimum counted value; and controlling the switch based on the determined second turn-on time in the second control mode to transfer energy via the transformer, wherein the second turn-on time in the second control mode is a constant turn-on time for the switch only when the dimmer is decoupled with the switch.