A while back, I did a teardown on a dual-channel Amrel PPS-2322 programmable power supply, and was quite impressed by its solid construction. Recently, I found another Amrel power supply on eBay and this time it is a single channel version (PPS 35-2). Let’s take a look inside this signal channel version and see how much in common it has compared to the dual channel 2322.
The single channel version of the Amrel programmable power supply has front panel sensing terminals making it handy for remote sensing applications. Although the dual channel version has remote sensing capability as well it is only available through wiring at the rear terminal block so it is less convenient.
With further review:
Clearly, this board’s design is shared between both the single channel and the dual channel versions of the power supply. Like the controller board found in the PPS 2322, the processor board contains a CPLD (GAL16V8B) chip, two SRAM chips (MPM81C55P-2 is a 2K SRAM and M58725P is a 16K SRAM), and a 80C31 microprocessor (DMC60C31E, which is essentially a ROM-less 8051).
The NI chip (CP02613) is presumably the GPIB controller (although I could not find any information on this chip). The firmware is stored in the UV-erasable EPROM (the firmware version of my unit is 7.00B).
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