Need to know the grounding path for LNK306PN
Hi,
We have used a design having LNK306PN. The output of the LNK306PN which is a 12V is connected to another voltage regulator for converting to +5V. This +5V is connected to a microcontroller board having sensistive capacitive touch sensors. When we turn on, everything works properly except the capacitive touch sensors. When i probe the output of the LNK306PN, it is 12V perfect DC and the output of the other voltage regulator, the voltage is 5V DC.
Please check the attached schematics having LNK306PN.
When i connect the same microcontroller board to a standard DC power supply or a samsung charger output, the microcontroller works fine with all the capacitive touch sensors.
I am unable to understand the grounding concepts with LNK306PN. Please check the attached schematics and let me know.
Comments
Hi Jedidiah.
Im have problem too. but im read and search and add 1 cap 1000pF/1kV in line S and GND and this working (im using LNK306 for power).Before not add C80 it not work or work not good, im add this cap it work fine but i dont know. Can you explain for me ??? It dangerous ?
| Attachment | Size |
|---|---|
| 123.PNG (66.94 KB) | 66.94 KB |
Hi HoangThinh,
The capacitor you placed across Drain to Source helped in reducing the ringing on your Drain to source waveforms. It reduced the EMI that might have caused the interference with the capacitive touch sensor before.
Its ok to use 100nF with 1000kV rating.
Regards,
Jedidiah
Hi Jedidiah.
Oh but i never see any in schematic before, i will test and try 100nF. But 1 problem more, when using them the inductor causing noise more than before ??? The inductor is 6100-152K-RC , 1500mH 510mA , im do not buy RFB1010-152 in reference design. How to reduce noise inductor
Regards,
Hoang Thinh
Hi HoangThinh,
Can you elaborate more what do you mean by noise inductor? Sorry, but I can' understand what do you mean with your whole statement in your last post.
Regards,
Jedidah
Hi SV,
I think that the capacitive touch sensors is sensitive to certain frequency. If that frequency is not reduced or filtered enough with the power supply used to power it up, it will interfere with the capacitive sensors sensitivity. The schematic that you sent also has no isolation. Samsung charger has isolation so the ground path of the secondary side or the output is isolated. That's the difference of the ground path of the two topology/circuit.
Regards,
Jedidiah