UCC28950-Q1: Burst mode

kura

Genius 4840 points

Part Number: UCC28950-Q1
Other Parts Discussed in Thread: UCC28950

We got a question about burst mode of UCC28950-Q1 from customer.

Their simulation result is attached.

8321.UCC28950.xlsx

Is it possible to adjust the ratio of the burst mode (the number of energized cycles) and the intermittent period?

* Specifically, They want to set the average to 10%or less.

Please advise us.

Regards,

Kura

over 2 years ago

0 Mike O' over 2 years ago

TI__Guru* 86286 points

Hello,

I have received your inquiry and it is under review.

Regards,

0 Mike O' over 2 years ago in reply to Mike O'

TI__Guru* 86286 points

Hello,

I just want to clarify is it the light load burst mode you are trying to adjust?

Regards,

0 kura over 2 years ago in reply to Mike O'

Genius 4840 points

They would like to adjust the burst mode ratio (the number of energization cycles) and the intermittent period.

0 Mike O' over 2 years ago in reply to kura

TI__Guru* 86286 points

Hello,

1. Is this light load burst mode you are trying to adjust?

2. This device will go into an over current protection/hiccup burst mode. I just want to clarify which one you are trying to adjust before making recommendations.

Regards,

0 kura over 2 years ago in reply to Mike O'

Genius 4840 points

Their question is about burst mode at light load condition.

0 Mike O' over 2 years ago in reply to kura

TI__Guru* 86286 points

Hello,

Your inquiry is under review and I will get back to you shortly.

Regards,

0 Mike O' over 2 years ago in reply to Mike O'

TI__Guru* 86286 points

Hello,

I researched this and is not possible to adjust the energizing cycles in burst mode.

The light load burst mode works by terminating the gate drives when the voltage amplifier demands a lower on time than programed by the Tmin pin with the RTmin resistor. When the voltage amplifier demands a on time greater than the minimum on time gate drive signal will return. At light loads this will actually burst the gate drive and duty cycle (D).

Vout/Vin = Ns/Ns*D = ton/tp

Regards,

Power management

Power management forum

UCC28950-Q1: Burst mode