LM5116

KrishnaKumar R

Other Parts Discussed in Thread: LM5116

Hi guys

I tried a buck converter using LM5116 with reference to the schematic in section 8.2 of the LM5116 datasheet , which is designed for an output of 5VDC / 7A.

My problem is that, inspite of having used the exact values of the components mentioned in the schematic, I don't get the specified output. Instead I get Vout = Vin, where in i changed my Vin from 10VDC to 50VDC. Somebody please help me ASAP.

Below I've attached the same schematic for reference.

Thanks and Regards,

KrishnaKumar R.

over 9 years ago

0 EricLee over 9 years ago

TI__Guru 58761 points

Hi
Please check your feedback resistor divider connections. If it is grounded accidently, the high-side switch will turn on at its max duty cycle limit and the output will be out of regulation.
Regards,
EL

0 KrishnaKumar R over 9 years ago in reply to EricLee

Prodigy 20 points

Yes, I've checked the feedback resistor dividers. As i want an output of 12VDC, i've used 1.21k and 10.7k for the divider. But i still i get only 3.8VDC. Inductor value is 10uH.

0 EricLee over 9 years ago in reply to KrishnaKumar R

TI__Guru 58761 points

What does this mean ? ==> Instead I get Vout = Vin

I thought that you got the output voltage which is the same as the input voltage.

Regards,

Power management

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LM5116