UCC5320: Isolated High Side SW

tateo yamashiro

Part Number: UCC5320

Hi,

We got a question from the customer about UCC5320.
Could you help us?

[Question]
They are considering using UCC5320 as isolated high side SW for relay driving. Please refer to below figure.

- Are there any concerns for this usage?
- What is the recommended terminal processing of each unused terminals(IN-, OUTL)?

Best Regards,
tateo

over 5 years ago

0 Mateo Begue over 5 years ago

TI__Intellectual 2805 points

Hello Yamashiro-san,

I am the applications engineer for this device and I will help you with your question.

1) Is the 1-A max requirement a peak source current requirement or a constant current (100% duty cycle) requirement? Our gate drivers are used to provide high source and sink currents but cannot maintain high output currents.

2) I believe both OUTL and OUTH need to be connected to the relay in order to provide sink current (if the control scheme is modulation based)

3) Unused inputs should be connected to GND1. OUTL should be connected to VEE2 if not needed (but I think the correct operation needs both OUTH and OUTL)

regards,
Mateo

0 tateo yamashiro over 5 years ago in reply to Mateo Begue

Guru 10890 points

Hi, Thank you for your support. I'll confirm with the customer and let you know by next week end.

Best Regards,

tateo

0 Mateo Begue over 5 years ago in reply to tateo yamashiro

TI__Intellectual 2805 points

While we wait for customer, can you help me understand why the customer needs an isolated gate driver to drive a relay?

regards,
Mateo

0 tateo yamashiro over 5 years ago in reply to Mateo Begue

Guru 10890 points

Hi, They are concerned the bad noise effect to the digital board from the high voltage board. Therefore they would like to use isolation switch.

Best Regards,
tateo

0 Mateo Begue over 5 years ago in reply to tateo yamashiro

TI__Intellectual 2805 points

Thank you for the insight, I am looking forward to your customer's feedback

0 tateo yamashiro over 5 years ago in reply to Mateo Begue

Guru 10890 points

Hi, Sorry to delayed reply. I discussed with customer.

- The current of gate driver is DC 20mA.
- It doesn't need sink current. Only source current.

Please refer to below figure for the details. Are there any concerns about this usage?

Best Regards,
tateo

0 Mateo Begue over 5 years ago in reply to tateo yamashiro

TI__Intellectual 2805 points

20mA DC is within the safety limiting values of this device, as shown in section 8.8 of the datasheet. The safety limits are 36mA max and 1.09W max on the output of the UCC5320SCD.

It is important to ensure the junction temperature does not exceed a maximum of 150C. This is affected by the ambient temperature and the power dissipation.
Please refer to the thermal information in the datasheet and the application note, http://www.ti.com/lit/an/spra953c/spra953c.pdf for more information.

This application should work as long as the UCC5320S remains within the safety limiting values.

If this answered your questions, please press the green resolved button .

Regards,
Mateo

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UCC5320: Isolated High Side SW