Chapter 4 Differences
Digital Signal Processor (DSP) Board
The DSP board replaces the Secondary Interface section of the A1 Main PC board. It replaces the Secondary Microprocessor (U504), the CV and CC programming DACs, Readback D/A, DAC Reference, Readback Comparators, and the Fan and Overvoltage PWMs. It replaces everything found in Figure
The DSP board contains the new Secondary Microprocessor circuits, the CV, CC, OV, OC and Fan DAC’s, The readback circuits and the secondary ROM and RAM. When operating in the Fixed mode, the instrument acts like a normal power supply with typical crossover characteristics between CV and CC operation. When in SAS mode the customer specified I/E operating curve is entered into the secondary RAM where it is used to modify the supply’s crossover characteristics.
Troubleshooting is to be performed in the Fixed
Note The DSP board is available as a replacement assembly only. It is not intended to be repaired to the component level.
The following figure is a simplified diagram that shows the circuits located on the DSP board (also referred to as the Secondary Interface) in relation to the Output Power and Control circuits previously discussed in chapter 4.
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