| 摘要 |
<p>A constant power light emitting diode (LED) driving circuit includes: a controlled voltage stabilizing unit (DY1) for providing operating voltage for an LED illuminating assembly (DY4, GN6) through a voltage-current sampling unit (DY2, GN5), wherein the operating voltage applied across the LED illuminating assembly (DY4, GN6) is in an inverse proportion relationship to the operating current flowing through the LED illuminating assembly (DY4, GN6), and the product of the operating voltage and the operating current is constant; the voltage-current sampling unit (DY2, GN5) for providing an operating voltage feedback signal and an operating current feedback signal to a composite error signal processing unit (DY3); the composite error signal processing unit (DY3) for calculating and combining the operating voltage feedback signal and the operating current feedback signal into a composite error signal, and controlling the operating voltage output from the controlled voltage stabilizing unit (DY1) through the composite error signal. In this circuit, the power applied on the LED illuminating assembly (DY4, GN6) will not vary due to the difference in the values of an operating voltage drop (VF); thus, the stability and the operating life of the LED illuminating assembly (DY4, GN6) are improved.</p> |
