UCC27537: Help check UCC27537 schematic

Star Xu

Part Number: UCC27537

Please help check the attached schematic.

The main trouble is when the device fails it causes a high voltage on the PWM pin which goes to the CPU and then kills the CPU.

Any comments or suggestions appreciated.

Thanks

Star

over 7 years ago

0 Mateo Begue over 7 years ago

TI__Intellectual 2805 points

Hello Star,

Thank you for using the UCC27537, I am an applications engineer for this device.

I will review your schematic and get back to you soon.

Regards,
Mateo

0 Star Xu over 7 years ago in reply to Mateo Begue

TI__Genius 9645 points

Hello Mateo
Thanks for your reply.
Any suggestion with this schematic.

Thanks
Star

0 Mateo Begue over 7 years ago in reply to Star Xu

TI__Intellectual 2805 points

Hello Star,
The schematic looks okay to me.

I suggest you send these parts through FA.
When the device fails, does the FET fail too? Do you know what the conditions are when the failure happens?

Lastly, make sure the PWM gnd is the same as the driver's gnd. I could not tell from the schematic how the PWM input is grounded.

regards,
Mateo

0 Jeffrey Mueller over 7 years ago

TI__Genius 12990 points

Hi Star,

How is this issue going? do you still need help solving your high voltage problem making its way to the input?

Thanks

0 Muzakkir over 6 years ago

Prodigy 10 points

Hi,

I'm sorry if continuing this here is wrong, please inform me and delete this if it is.

I've tried to just turn on this MOSFET with 5V, but i only get ~3.5V at the LED which is not enough.

I'm planing to use UCC27537 to drive the MOSFET, will it work to get full 24V to the LED?

Please help, thank you.

0 Jeffrey Mueller over 6 years ago in reply to Muzakkir

TI__Genius 12990 points

Hi Murzakki,

The reason why you see 3.5V on the LED is because there is a 20.5V drop on the 1R5k but because the LED is after the drop of R12 it sees this lower voltage.

Simply changing the driver will not solve this issue because the circuit is the limiting factor.

Can you tell me more about your LED? when the LED is on what is the voltage drop on it? are you limited to 24V for VIN? 15mA?

Thanks

Power management

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UCC27537: Help check UCC27537 schematic