LM73606: Boot-SW UVLO

Shinya Sawamoto

Part Number: LM73606

Hello,

I'd like to know how to work Boot-SW UVLO, let me ask a couple of questions as follows.
1) When Boot-SW UVLO is detected, how the device behaves? (latched-off or auto-retry?)
2) Is the Boot-SW UVLO have something mask(deglitcher) period? (to know about its noise tolerance)
3) Is it monitored in anytime or something of sampling window in the switching sequence?

Thanks in advance.
S.Sawamoto

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Shinya,

1. Datasheet, 7.3.11 "The device initiates a charging sequence using the LS switch before turning on the HS switch."

2. I believe this is sensed before every HS turn-on but I will check and confirm.

3. See 2.

-Sam

0 Shinya Sawamoto over 6 years ago in reply to Samuel Jaffe

TI__Expert 5285 points

Thanks for the swift feedback, Sam,

I'm looking forward to hearing about No2&3.

Regards,
S.Sawamoto

0 Samuel Jaffe over 6 years ago in reply to Shinya Sawamoto

TI__Mastermind 25590 points

S.Sawamoto,

The boot UVLO is checked during High-Side ON. High-side will be turned off if UVLO is tripped regardless of where the inductor current is at that time.

-Sam

0 Shinya Sawamoto over 6 years ago in reply to Samuel Jaffe

TI__Expert 5285 points

Thanks Sam,

I think the attached waveform seen on my bench is the boot UVLO protection, is it correct?
I saw this behavior when I add 10 ohm resistor in series to the boot cap for attempting to slow the switching rise time.
The waveform shows 2.5MHz shutdown & resume switching although the Fsw is set to 400kHz.

Regards,
S.Sawamoto

0 Samuel Jaffe over 6 years ago in reply to Shinya Sawamoto

TI__Mastermind 25590 points

S.Sawamoto,

Yes, that looks like boot UVLO.

-Sam

Power management

Power management forum

LM73606: Boot-SW UVLO