48V Quasi-Resonant Inverse Buck LED Driver

Open online SPICE simulator circuit link: lighting_led_48V_inverse_buck_qr.tsc

48V Quasi-Resonant Inverse Buck LED Driver

Inverse buck circuits are ideal for driving high brightness LEDs with high efficiency. This example
drives three ~11V Lumileds LEDs at 1A (100% dimming level) with 48V DC input. The selected
80V OptiMOS™ MOSFET is perfect thanks to its low cost, low gate charge and low \i(R,DS,on).
The duty cycle is selected in such a way that this circuit operates in quasi-resonant mode. The
MOSFET is turned on in the first valley. A zero-crossing detection signal is generated for the
controller (e.g. XMC1000) by capacitive coupling.

LEDs

VDC IN