LM34936: LM34935 Design Issue

Jerry Chu

Genius 4915 points

Part Number: LM34936

Hi Expert,

1. VIN=13V

2. Fsw=370KHz

3. Vout=20V

4. Iout=3A

5. MOSFET= DMT4011LFG-13

6. Output Cap around 500uF

7. CSLOPE=100pF

8. DITH=GND

9. L=4.7uF

10. CCM mode

11. Comp circuit follows the webench

When the 20V@3A, will get the audio noise and output ripple Vp-p is 3V. Any suggestion for it?

WBDesign319.pdf

over 4 years ago

0 Youhao Xi over 4 years ago

TI__Guru 68495 points

Hi Jerry,

The Webench schematic does not show problems. What is your actual schematic that you used to create your PCB? Also, can you show the SW1 and SW2 waveforms so we can understand the problem better?

Note that, if you have new info, we will get back to you by next Tuesday US time.

Thanks,

Youhao Xi, Applications Engineering

0 Jerry Chu over 4 years ago in reply to Youhao Xi

Genius 4915 points

Hi Youhao,

After changed to LM34936, seems more stable. Thanks!

0 Youhao Xi over 4 years ago in reply to Jerry Chu

TI__Guru 68495 points

Hi Jerry,

Thank you for the update. Let me close the thread here and feel free to add an new post if you have further questions.

Thanks,

Youhao

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LM34936: LM34935 Design Issue