Driving circuit for driving light-emitting diodes by IR53HD420

The picture below shows the novel circuit of IR53HD420 driving light-emitting diodes. VDC in the picture is DC 320V. It is obtained from 220V AC through rectification and filtering. The IR53HD420 output produces 320Vp - crimped to a series combination of compact fluorescent tubes and a current limiting inductor Ll, and connected to a parallel capacitor to create LC resonance for heating. Light up fluorescent tubes. And provide lamp current. The device works great. The compact fluorescent tube voltage is typically 150Vp-p. Connect dozens of LEDs (LEDI-LED64) in series. and connect them to a bridge rectifier (D1-D4). At least it can simulate the effect of a compact fluorescent lamp when it is on. The values ​​of Rt and Ct given in the figure make the bridge work at 70kHz. The current provided by this circuit to 64 LEDs is approximately 80mA. The LED current consists of DC plus a small pulsating current. Keeping the pulsating current low is beneficial to achieving high efficiency and extending the service life of the LED. During an oscillation cycle, the voltage at the input terminal of the LED rectifier remains unchanged. Therefore the current in inductor L1 is a triangular wave. This is good for EMC (electromagnetic compatibility). The average LED current equation is IlEDAug=(1/2VDC-NxVFled), (4xfxLl), where VDC is the power supply and N is the number of LEDs connected in series. Vnm is the LED forward voltage drop. f is the oscillation frequency. L1 is the inductance of the current limiting inductor.