Functional Block Diagram of IC 723 Regulator IC 723 has two sections. As shown in the block diagram, A constant current Source:- A zener diode and a reference amplifier producing a constant voltage of about 7 volts at Vref end. The zener diode is being compelled to operate at fixed point (so that zener output voltage is a fixed voltage) by a constant current Source. The second section of IC 723 comprises of an error amplifier, a series pass transistor Q1 and a current limiting transistor. The error amplifier compares a sample of output voltage applied at Inverting input terminal to the reference voltage Vref applied at the Non-Inverting input terminal. The conduction of the transistor Q1 is controlled by the error signal. Back To HOME