Power Supplies

The integrated-circuit stabiliser

The modern tendency in stabilised power supply design is to use an integrated circuit (IC) regulator. This contains in one small package the series element, reference voltage supply, a high-gain error amplifier and various sensing resistors and transistors. The more complex versions also contain protection circuits against too much voltage being applied to them and excess temperature rise. They are relatively cheap and are available up to a maximum regulated current of 10A. They may be connected in parallel for higher currents.

The simplicity of this type of power supply may be seen from Fig 6.12. The layout of such a power supply can be critical and, in particular, the connections between the integrated circuit and the 2μF capacitors should be short to avoid any instability arising from parasitic oscillation.

Fig 6.12. Practical power supply unit using IC regulator