TIDA-00961: What if PWM is switched faster than 1.2 MHz?

Hi, Wayne

As I am not the primary owner of this design, I need some time to do the test for 115V 100W conditions.

For the sencond question, I think it is will happen on very light load conditions. The PFC stage could be shutdown or enter burst mode, I think.

Dear Watermelon Melon,

We will wait for your reply on (1).

For question (2), the existing design is based on 1 MHz.

Because for higher PWM, the physical size of inductors can be smaller, they wonder if we have any idea/suggestion/plan for this.

This is not only for very light loads.

Wayne

Hi, Wayne,

Theoretically, the switching frequency canbe boost to 1.2MHz with this design, but it need much effort I believe.

Firstly,  the PWM resolution will need to use high resolution PWM, 10ns step of PWM maybe not enough;

Then, the deadtime of main switch will take larger percent of whole PWM period, which may need more exactly adjustment;

Thirdly, be careful of the driver's delay, it may increase the OCP level to an unexpected level, especially during input voltage surge.

While, related to the control & ZVS adjust, they may use similiar frequency, without following with increased switching frequency.