LM5161: The power output affects the accuracy of sensor

Hui Cao22

Part Number: LM5161
Other Parts Discussed in Thread: LM5160

The problem we are currently encountering is that when using the LM5160DNTJ chip and the isolated power supply application solution, the voltage variation after isolation has an impact on the accuracy of the subsequent sensor when the input voltage changes.

The following location issue has been identified. Disconnecting resistor R131 and supplying power to the subsequent stage from another source is fine. By adjusting R136 and C140, there has been an improvement, but the effect is not satisfactory. Could you give some advise,thanks.

The problem is located in the red box The influence of power supply changes on accuracy.png

8 months ago

0 ARPITA NATH 8 months ago

TI__Genius 15562 points

Hi Hui,

can you please confirm whether you are using LM5160 or LM5161?

Please clarify which node you are measuring the above voltage level??

regards

Arpita

0 Hui Cao22 8 months ago in reply to ARPITA NATH

Expert 1270 points

Sorry, LM5160, the wrong title.

Our customer's product is a smart meter. The vertical axis of the last picture represents the current accuracy collected by the MCU. Currently, if the LM5160 is replaced with a DC source to supply power to the LDO, the accuracy will be normal. When connected to the LM5160, there will be this problem of accuracy fluctuation and inaccurate accuracy. We have identified the part in the red box. Could you please tell us which factors would affect this result? Tomorrow, I will send you the transformer parameters and the output waveform of the LM5160 for your reference.

0 ARPITA NATH 8 months ago in reply to Hui Cao22

TI__Genius 15562 points

Hi Hu,

Apologies for delay in response

Can you please send the part no? I will review the schematic in details. Also please plot the output voltage (secondary) of the device.

+1 ARPITA NATH 8 months ago in reply to ARPITA NATH

TI__Genius 15562 points

Hi Hu,

I just saw that you have shared the above requested details (Vout variant, waveforms, part numbers) in the other E2E thread:

LM5160: Output transformer and peripheral design check - Simulation, hardware & system design tools forum - Simulation, hardware & system design tools - TI E2E support forums.

I will close this thread and let's continue discussing on the other thread.

Regards

Arpita

0 Hui Cao22 8 months ago in reply to ARPITA NATH

Expert 1270 points

OK, many thanks for support

0 ARPITA NATH 8 months ago in reply to Hui Cao22

TI__Genius 15562 points

You are welcome.