CCS/UCD3138: How to use the burst mode or light load mode in HSFB EVM ?

user5006419

Expert 1795 points

Part Number: UCD3138

Tool/software: Code Composer Studio

How to use the burst mode or light load mode in HSFB EVM ?

I find LL_EN=0 ,

when LL_EN=0 but it doesn't work in burst mode ?

Are there any other requirements to be set ?

Thanks .

over 6 years ago

0 Amiel Hussain over 6 years ago

TI__Expert 4040 points

Hello,

Your question is being forwarded to the appropriate engineer.

Amiel

0 Yitzhak Bolurian over 6 years ago

TI__Mastermind 18370 points

LL_EN should be set to 1 in order for light load mode to be active.
Also the TURN_ON_THRESH and TURN_OFF_THRESH shold be set.
When output of voltage mode digital filter in lower than threshold, you will enter the light load mode and start pulse skipping.

Regards,

0 user5006419 over 6 years ago in reply to Yitzhak Bolurian

Expert 1795 points

#define TURN_ON_THRESHOLD (2000)//(25000)
#define TURN_OFF_THRESHOLD (1000)//(25000)
I find the TURN_ON_THRESH and TURN_OFF_THRESH are set .
If TURN_ON_THRESH and TURN_OFF_THRESH are set more high , it will enter the light load mode and start pulse skipping?

0 Yitzhak Bolurian over 6 years ago in reply to user5006419

TI__Mastermind 18370 points

Yes. That should work.

0 user5006419 over 6 years ago in reply to Yitzhak Bolurian

Expert 1795 points

1. LL_EN=1 , in the HSFB code
2. TURN_ON_THRESH and TURN_OFF_THRESH set more higt , in the HSFB code
The result is no PWM and Vout is 0 , there is not in burst mode .
I guess syncFETs not ramped up is cause the problem ("//light load enabled and syncFETs are not ramped up" , I find in the "handle_regulated_state")
Other registers need to be set in the HSFB code ?

0 Sean Xu over 6 years ago in reply to user5006419

TI__Genius 13570 points

Hi,

Set TURN_ON_THRESH is higher than TURN_OFF_THRESH for the burst mode.

The burst mode is independent of syncFETS ramp. The output voltage is zero, it may be because the Vo ramp is not finished or enabled properly.

Regards,

Sean

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CCS/UCD3138: How to use the burst mode or light load mode in HSFB EVM ?