Circuit : Andy Collinson
A DC converter circuit taking one single DC input and converting to parallel multiple DC outputs.
This circuit uses a single DC input (nominally 12 Volt) and converts to four simultaneous output voltages of 9, 6, 5 and 1.5 Volts. The output voltages are controlled by common 78xx series regulators, offering 9, 6 and 5 Volt DC outputs. The 1.5 Volt supply is derived using an LM317 regulator. To reduce power and heat the LM317 is fed from the 5 Volt regulator output.
The LM317 output is calculated from:
Vo = 1.25 (1 + R1/R2)
With R1 200 ohms (use 180 plus 22 ohm in series) this works out to be 1.5 Volt. F2,3,4,5 are the output fuses and are set at 500 mA (0.5 A). If the full 500mA is taken from each output then the DC input supply must be capable of sourcing at least 2 Amp. LED 1 illuminates to show the circuit is in operation.