Design of Transistor Regulated Power Supplies

A new form of transistor series regulated power supply is presented which permits unusually good performance characteristics to be realized with simple and economical circuitry. Expressions are given for the open-circuit output voltage and the output resistance in terms of the supply voltages and the circuit parameters. Application of the new circuit to two practical laboratory regulated power supplies is described, the specifications of which are: 0.5 ampere at 18 to 22 volts, and 1 a at 5 to 25 v. The output resistance is of the order of 0.01 ohm for both supplies; for sudden change of load current between minimum and maximum the transient in output voltage is 80 mv or less, and decays in 40 μsec or less. At full load, ripple in the output voltage is less than 5 mv and line voltage variations of ±10 per cent produce output variations of less than 5 mv. Each supply uses only one line transformer.