programmable power supply - digital/analogue power supply interface

programmable power-supply elektor october 1983 E. Stahr Many integrated circuits are now so familiar to most of us that we tend to overlook some of their remarkable characteristics. Here we take a well-known voltage regulator, the 723, and hook up a digital/analogue converter to its input and the result is that we can program the output voltage very precisely and can also select the maximum output current (with a digital command, no less!). This circuit should interest anybody who wants to use the "digital" accuracy of a microprocessor system to meet stringent analogue requirements. programmable power supply digital/ analogue power supply interface We are not dealing here with an ordinary digital/analogue converter: its conversion time of 5 ps is, of course, pretty good but its high output current of 2 A is far from ordinary (see technical characteristics). The programmable output voltage is divided into three digitally switched ranges as is the case with the output current. Circu...