UCC2813-4: Thresholds at 70V VCC

Jejomar Ildefonso

Part Number: UCC2813-4

Hello Team,

Good day! Need your inputs on this. Our customer wants to operate the UCC2813-4 at 70V and 60V VCC as the turn-on and off threshold respectively. Is it possible to do this through a voltage divider configuration at the supply stage? This is also while ensuring the given threshold value range and ICC at 30mA through the current limiting resistor. If so, are there any other conditions to be considered?

Thanks in advance!

Kind Regards,

Jejomar

over 3 years ago

0 Teng Feng over 3 years ago

TI__Genius 13660 points

Hi Jejomar,

UCC2813-4 does't have input ON_OFF function. I think if you want to feature input ON_OFF with hysteresis, a hysteresis voltage comparator circuit should be required to added in the circuit to control the COMP.
Regards,

Teng

0 Jejomar Ildefonso over 3 years ago in reply to Teng Feng

TI__Expert 8590 points

Hello Teng,

Thanks for looking into this. What I meant was the UVLO threshold of the UCC2813-4. Our customer wants to utilize the threshold in a way that a 70V supply would turn on and 60V would turn the device off through UVLO. We're trying to look at a voltage divider in the supply stage to achieve the required thresholds on the input pin while maintaining the supply current through the current limiting resistor. Would this be applicable or do we have to consider other conditions?

Kind Regards,

Jejomar

0 Teng Feng over 3 years ago in reply to Jejomar Ildefonso

TI__Genius 13660 points

Hi Jejomar,

Sorry, I can't image such a circuit, could you provide the schematic?

Thanks

Teng

0 Jejomar Ildefonso over 3 years ago in reply to Teng Feng

TI__Expert 8590 points

Hello Teng,

I understand. Current I only have the raw schematic from the customer. I'll ask him to directly engage to this thread for the schematic representation of the inquiry.

Kind Regards,

Jejomar

0 Giuseppe Busi over 3 years ago in reply to Jejomar Ildefonso

Prodigy 70 points

Hi to everybody,

I've attached the schematic of the power supply circuit.

Please consider, from your point of view, that pin J1.4 is short circuited to the pin J1.5.

The voltage at the net "VDC" is variable (220VAC -> 340VDC, or 3x400VAC -> 650V).

I hope there's a suitable way to solve my problem.

Thanks a lot.

Regards,

Giuseppe

2235.PowerSupply.pdf

0 Teng Feng over 3 years ago in reply to Giuseppe Busi

TI__Genius 13660 points

Hi Giuseppe,

I think this circuit should be able to realize the turn on function if the resisters are set right. But I have no idea how it disables the devices below 60 V DC input. A solution is to use an external transistor to pull the error amplifier output low below 60 V.

Regards,

Teng

0 Giuseppe Busi over 3 years ago in reply to Teng Feng

Prodigy 70 points

Comparator.pdf

0508.PowerSupply.pdf

0 Teng Feng over 3 years ago in reply to Giuseppe Busi

TI__Genius 13660 points

Hello,

From my view, in the schematic of Comparator.pdf, the comparator threshold is larger than 60 V, can you provide you calculation formulas?

And do you have any further questions?

Regards,

Teng

0 Giuseppe Busi over 3 years ago in reply to Teng Feng

Prodigy 70 points

Hi Teng,

you are in right, in fact with such values of resistor the turn-on threshold is around 93V and the turn-off threshold is around 84V (obtained with Spice).

I want to thank you for your time.

No futher questions.

Regards,

Giuseppe

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UCC2813-4: Thresholds at 70V VCC