LM51551-Q1: Do we suggest to add the resistor at BIAS_PIN?

Pin Tsai (TW FAE)

Part Number: LM51551-Q1

Hi Expert,

My customer is using LM51551-Q1 as the flyback controller. They want to know if we suggest to put the resistor at BIAS pin to limit the current. Since they have put the 10 ohm in old project, and they want to know the necessity of this.

Do you have any suggestion on this?

Thank you,

over 2 years ago

0 Brigitte over 2 years ago

TI__Guru 58215 points

Hello Pin,

We are normally not using a resistor in the BIAS supply.

For his design, I would recommend to remove it and check if something is happening in his application. There might be a reason that it was placed in the first place.

Best regards,
Brigitte

0 Pin Tsai (TW FAE) over 2 years ago in reply to Brigitte

TI__Intellectual 2280 points

Hi Brigitte,

Thank you for response.

Here is the customer schematic, they bias is connected to the 12V car battery through the protect diode.

Can you help to review and let me know if there is anything need to be modified ?

Thank you!

0 Brigitte over 2 years ago in reply to Pin Tsai (TW FAE)

TI__Guru 58215 points

Hello Pin,

The secondary side is missing and in addition, the minimum information needed to review a design is input voltage range, output voltage and maximum output current. Please use the quickstart calculator to check: https://www.ti.com/lit/zip/snvc240

Best regards,
Brigitte

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LM51551-Q1: Do we suggest to add the resistor at BIAS_PIN?