TPS62740: -Startup time is not deterministic, has a variable delay after Enable assertion

Barry Rowland

Part Number: TPS62740
Other Parts Discussed in Thread: TPS62800

Dear TI people; As per the title line: The spec is pretty 'loose' on the startup delay, I wondered if there is any better characterisation, or whether this start-up delay depends on Vin, for example?

I havw an application where I want to have a vaery short startup delay, and wondered, then, if there is any way to be able to 'pipeline' this start-up delay, which I could do if it was deterministic... in a real-time system, a 2.5 ; 1 variation in a behaviour is kind of hard to deal with!

Any ideas??

over 6 years ago

0 Chris Glaser over 6 years ago

TI__Guru**** 150830 points

Hi Barry,

Is the softstart delay (of 10 msec typical) too long or is the variation the issue? The TPS62800 family has a much shorter delay time.

The delay time spec includes the temperature variations, which are a dominant factor.

If this is an issue, another option is to use the load switch, instead of the EN pin.

0 Barry Rowland over 6 years ago in reply to Chris Glaser

Intellectual 550 points

Hi Chris;

For my purposes, the delay variability is the main issue, although the 'usual' soft-start with no delay is better ;-)

If the delay is quite fixed, I can 'pipeline' my tests around it, that is, I could start up the part 10 ms 'early'.... I will be exercising the DVS lines and LOAD/Control, as well, during my test cycles.

Thank you, sir,

Barry

0 Chris Glaser over 6 years ago in reply to Barry Rowland

TI__Guru**** 150830 points

Thanks for explaining.

Let me see if I can find some data to share with you offline, under NDA.

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TPS62740: -Startup time is not deterministic, has a variable delay after Enable assertion