TLV767: 50DRVR 16V input dissipates 170Mah as heat. What did I do wrong?

Johannes Leenders

Part Number: TLV767
Other Parts Discussed in Thread: LP5024

I've been working happily with the TLV76750DRVR for 6 months, operating at 5,4V in and 5V out.

I was testing it on 12V input, it works yes but it generates a lot of heat.

Is there something obvious I missed?
https://www.ti.com/lit/ds/symlink/tlv767.pdf

Going for a redesign this week and would love to get this working at 12V without the large power disipation.

over 4 years ago

0 Johannes Leenders over 4 years ago

Prodigy 10 points

Weird, the boards I shipped yesterday did not like the 12V.

The "broken" boards I have don't seem to have this problem.

It's powered by a 4Ah 12V battery, this is half empty now going to charge it and test again.

0 Jason Song over 4 years ago in reply to Johannes Leenders

TI__Mastermind 23361 points

Hi Johannes,

Thanks for the update. When pumping the input voltage from 5.4V to 12V, with the same load current, the power dissipation will be more than doubled. What's the typical load current in your application?

Regards,
Jason Song

0 Johannes Leenders over 4 years ago in reply to Jason Song

Prodigy 10 points

Hi Jason,

Thanks for your reply.

@5.4V maximum is 70Mah -150Mah and the TLV767 does not really generate any heat.
@11.5V it was drawing 70Mah - 150Mah
@14.5V it was drawing ~300Mah

Need to check 14.5V again because my short circuit protection (diode) was also getting hot,going to remove this to see what the actual load is. When I put a temperature probe on the TLV767 it's ~80C.

Regards,

Johannes Leenders

0 Jason Song over 4 years ago in reply to Johannes Leenders

TI__Mastermind 23361 points

Thanks for the update. I will be waiting for your test results then.

0 Johannes Leenders over 4 years ago in reply to Jason Song

Prodigy 10 points

Without Diode it does ~30Mah less.
I have one board that does this and another that doesn't...

The one that doesn't draws a lovely 0.15Mah @12.5V...

+1 Johannes Leenders over 4 years ago in reply to Jason Song

Prodigy 10 points

Found it!
I have LP5024 and a few months back I decided that it did not need a current limiting resistor, to make it "easier" to find the right LED intensity I need. So I shorted it to ground, I removed the short and it "resolved" the issue. Getting 88Mah @12.5V, which is high, but might be due to the WiFi chip not connecting on this board.

Need to do some more testing, and think about the mistakes I made and what influence this is having on the code not working as intended during field test but does work during unit testing...

0 Jason Song over 4 years ago in reply to Johannes Leenders

TI__Mastermind 23361 points

I am glad you found the solution. Thanks for letting us know.

0 Johannes Leenders over 4 years ago in reply to Jason Song

Prodigy 10 points

it's kind of resolved yes.

The problem also kind of persists, but with lower values.

When the TLV767 is connected directly to the 12V it draws a lot more current and gets hot.

My current solution for this is using a AZ1117CH-5.0 I have a reel of lying around, not sure if the TLV767 is now obsolete....

0.3W with AZ1117 and 0.7W with just the TLV767 on 12V...

0 Jason Song over 4 years ago in reply to Johannes Leenders

TI__Mastermind 23361 points

Yes, splitting the power could help with the over-heat situation. TLV767 is our new device and there is no plan to obsolete the device.

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TLV767: 50DRVR 16V input dissipates 170Mah as heat. What did I do wrong?