The control circuitry
Here’s where it gets interesting. There’s rather a lot happening on the control side of the board.
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The big obvious 20 pin IC is an Intersil HIP6004B and sure enough the datasheet confirms that it is indeed a switching buck regulator with recommended applications that include the power supply for older generation CPUs.
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What makes this part interesting is the way that you select the output voltage. These days the typical method for setting the output voltage is to use a resistor divider but this device does it through a 5-bit digital input that feeds an onboard DAC.
The other IC up the top left is an LM324D quad op-amp. I honestly cannot think what that’s doing on here and my searching around to find example applications that include such an op-amp array in this configuration yielded nothing. Maybe I’ll be able to figure it out during testing.
There are a large number of test pads dotted around the board but unfortunately none of them are labelled with the expected value.
