LM3404HV: Thermal Shutdown - LM3404HV

Part Number:LM3404HV

Hi all,

We are facing some thermal issues with a prototype of 40W LED driver based on LM3404HV (SOIC8).We are trying to drive a 38V 1A COB LED from an integrated 52V Flyback SMPS.The Flyback SMPS and LED driver is on a same PCB inside a plastic enclosure.Its working fine as open frame but when the enclosure is closed,working for a few hours the LED starts to blink.We also tried separating the SMPS part but it doesn't helped.We now doubt both the frequencies,switching and dimming.Please help !

VIN - 52 V

Vout - 38V

Iout - 950mA

Rcs - 0.2 ohm

Fsw - 250Khz

Fdim - 500hz (3.3V)

Ron - 1meg

Diode - MBRS4201T3G (SMC)

Inductor - 100uh 1.5A 10x15 Drum

Thanks and Regards.