TPS54302 again...

[server]

TPS54302 is a wonderful little synchronous switcher chip.

3 amp switcher in SOT-23, under a dollar. It does radical
spread-spectrum pwm but the dc output is quiet.

We\'re designing a small box that contains about 400 power relays. To
reduce coil power, we\'ll run the relay coils at 12 volts and bump them
up to 24 briefly when we change setups. One issue is whether the
switcher can switch 24 to 24, full on, without its bootstrap cap
discharging. The TPS makes a tiny blip once in a while to recharge the
cap. It seems to do everything right.

They do get pretty warm at 3 amps.

We\'ve done a lot of testing on the eval board.

https://www.dropbox.com/s/jban5vjybbb2g77/TPS54302_PWM.JPG?raw=1

https://www.dropbox.com/s/etctkh2rzesockj/TPS54302_spectrum.JPG?raw=1




--

I yam what I yam - Popeye

 

[Phil Hobbs]

jlarkin@highlandsniptechnology.com wrote:

TPS54302 is a wonderful little synchronous switcher chip.

3 amp switcher in SOT-23, under a dollar. It does radical
spread-spectrum pwm but the dc output is quiet.

We\'re designing a small box that contains about 400 power relays. To
reduce coil power, we\'ll run the relay coils at 12 volts and bump them
up to 24 briefly when we change setups. One issue is whether the
switcher can switch 24 to 24, full on, without its bootstrap cap
discharging. The TPS makes a tiny blip once in a while to recharge the
cap. It seems to do everything right.

They do get pretty warm at 3 amps.

We\'ve done a lot of testing on the eval board.

https://www.dropbox.com/s/jban5vjybbb2g77/TPS54302_PWM.JPG?raw=1

https://www.dropbox.com/s/etctkh2rzesockj/TPS54302_spectrum.JPG?raw=1

Nice. When running from a lowish input rail, I sometimes use a 10k
resistor from the bootstrap pin to some higher supply to reduce the ON
resistance.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[server]

On Thu, 13 Jan 2022 11:47:03 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

jlarkin@highlandsniptechnology.com wrote:
TPS54302 is a wonderful little synchronous switcher chip.

3 amp switcher in SOT-23, under a dollar. It does radical
spread-spectrum pwm but the dc output is quiet.

We\'re designing a small box that contains about 400 power relays. To
reduce coil power, we\'ll run the relay coils at 12 volts and bump them
up to 24 briefly when we change setups. One issue is whether the
switcher can switch 24 to 24, full on, without its bootstrap cap
discharging. The TPS makes a tiny blip once in a while to recharge the
cap. It seems to do everything right.

They do get pretty warm at 3 amps.

We\'ve done a lot of testing on the eval board.

https://www.dropbox.com/s/jban5vjybbb2g77/TPS54302_PWM.JPG?raw=1

https://www.dropbox.com/s/etctkh2rzesockj/TPS54302_spectrum.JPG?raw=1




Nice. When running from a lowish input rail, I sometimes use a 10k
resistor from the bootstrap pin to some higher supply to reduce the ON
resistance.

Cheers

Phil Hobbs

That\'s another way to keep the highside fet on forever. In our case,
we have no higher voltage available.



--

I yam what I yam - Popeye

 

[Martin Rid]

jlarkin@highlandsniptechnology.com Wrote in message:r
> TPS54302 is a wonderful little synchronous switcher chip.3 amp switcher in SOT-23, under a dollar. It does radicalspread-spectrum pwm but the dc output is quiet.We\'re designing a small box that contains about 400 power relays. Toreduce coil power, we\'ll run the relay coils at 12 volts and bump themup to 24 briefly when we change setups. One issue is whether theswitcher can switch 24 to 24, full on, without its bootstrap capdischarging. The TPS makes a tiny blip once in a while to recharge thecap. It seems to do everything right.They do get pretty warm at 3 amps.We\'ve done a lot of testing on the eval board.https://www.dropbox.com/s/jban5vjybbb2g77/TPS54302_PWM.JPG?raw=1https://www.dropbox.com/s/etctkh2rzesockj/TPS54302_spectrum.JPG?raw=1-- I yam what I yam - Popeye

I use the tps69xxx, nice little part. Lots of current for a small
part.

Cheers
--


----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html