| 摘要 |
A switch mode power supply (SMPS) converter is periodically run backwards by using a synchronous switch instead of the normally used commutating diode. By running the SMPS converter backwards the SMPS output capacitor can be discharged very quickly to provide a fast turn off of (no current through) the LED's, thereby solving the color shift problem. This enables positioning the output voltage of the SMPS up or down by actively charging or discharging the bulk output capacitor. Having the capability of actively charging or discharging the bulk output capacitor allows generation of a current source comprising substantially square, e.g., substantially full current when on and substantially no current when off, current pulses that are preferable for driving LED lighting applications. |
