| 摘要 |
<p>A self-oscillating switch circuit for amplitude modulation dimming for dimming a LED load. The self-oscillating switch circuit comprises a high-power input terminal (S2) for supplying a first power to the load and a low-power input terminal (S1) for supplying a second power to the load. The switch circuit further comprises a power switch semi-conductor device (Q1) configured for controlling a load current from at least one of the high-power input terminal (S2) and the low-power input terminal (S1) to the output terminal. A control semi-conductor device (Q2) is configured to control the power switch semi-conductor device (Q1) in response to a sensing voltage. The sensing circuit comprises a first sensing resistor (R1A) and a second sensing resistor (R1B) for generating the sensing voltage such that a load current has a predetermined first peak current level corresponding to the first power, when power is supplied to the high-power input terminal, and the load current has a predetermined second peak current level corresponding to the second power when power is supplied to the low-power input terminal.</p> |
