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I have a cheap power supply that I am trying to modify. The 6G80 appears to be a regulator (driver) chip that drives an N-MOSFET. I do not have an oscilloscope with me, so I am unable to tell if it is running linearly or chopped. One side of the output winding of the SMPS goes to the storage capacitor positive. The other side of the winding goes through an N-MOSFET (D) with the (S) connected to the negative side of the storage capacitor. The gate is connected to the unknown chip. The output is a fixed 5.0 V at about 3 A, which is relatively stable over the load range.

I would like to increase the output voltage to 5.2 V, but would feel better understanding how the unknown chip is working, before I modify the circuit. If anyone has a datasheet for this chip, I would greatly appreciate it.

My gut tells me that I need to lower the voltage by 0.2 V going into pin 6 of the chip (voltage divider?) The rough diagram is attached for clarity.

IC reg chip circuit

NOTE: pin 1 is bottom left and follows IC conventions.

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    \$\begingroup\$ Please use the built in schematic editor, not to sound horrible but your diagram is hard to read, for example I have no idea what is going on with the upper left pin, and your mosfet part number, is that "MY" or "H4"? \$\endgroup\$ – Ron Beyer May 26 at 4:24
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    \$\begingroup\$ What about the PSU are you trying to modify? Can you show us a photo of the IC? \$\endgroup\$ – Bruce Abbott May 26 at 6:21
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    \$\begingroup\$ I can't find the art, but this article describes it (or a similar one) edn.com/… \$\endgroup\$ – Bruce Abbott May 26 at 6:40
  • \$\begingroup\$ Apologies about the schematic. First post ever. I will do better next time. \$\endgroup\$ – MalcolmL May 26 at 18:11

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