TIDA-00779: UCC27524DR and UCC28180D are failing.

Hi Vinu,

Have you followed the inrush current limitation circuit design? When power on, the relay should be turned off, use PTC to charge bus cap and then turn on the relay.

And minimum AC input voltage should be 150Vrms ac. 

Best Regards,

Jim

Hi Jim,

Yes, I have followed the inrush current limitation design, as shown in the attached PDF. I used a 4 A, 50 Ω PTC in the AC neutral line. When I apply 230 V AC (Vrms ≈ 162.63 V), the relay turns on after a very short delay. However, I am not sure why the IC is failing and the PWM is not being generated.

Best regards,
Vinu

Hi Vinu,

Does auxiliary power supply on board work normally? What's the voltage measured at VCC/VDD of UCC27524DR and UCC28180D?

Best Regards,

Jim

Hi Jim,

Yes, the auxiliary power supply on the board works normally. The voltage measured at the VCC/VDD pins of the UCC27524DR and UCC28180D is 13 V. When I provide the auxiliary power supply and VREF externally, the ICs work normally, and I am able to get the PWM. But when I apply the AC input, both the UCC27524DR and UCC28180D fail, and afterwards the ICs no longer work and no PWM is produced

I have included the boost follower control circuit exactly as provided in the TIDA-00779 reference schematic. Is this circuit mandatory, or can it be omitted?

Best regards,
Vinu

Hi Jim, 

Thanks for your support.

please support further, thank you so much.  

The PWM duty cycle is 96% under no-load conditions.

Hi Jim,

please support further. 

Hi Jim, 

Can you confirm whether the reference design requires that specific boost-follower circuit for proper IC startup?

Hi Vinu,

That's strange. Under no-load condition, the pwm duty cycle should be very small.

If you follow the schematic as TI design, i think the schematic would not be a problem.

I think you may remove the gate resistors of MOSFETs and power on again to check if any problems.