SERIES_REGULATED_LINEAR_POWER_SUPPLY

Published:2009/7/24 3:37:00 Author:Jessie | From:SeekIC

The ac line is isolated from the power supply by transformer T1. Full-wave diode bridge BR1 de-livers unregulated dc with ripple on it to the filter capacitor (C1.) The filtered dc is delivered to pass transistor Q1, shown here in series with the load. The series-pass regulator with a transistor pass element regulates the voltage to ensure that a constant output level is maintained, despite variations in the power line voltage or circuit loading. The basic linear series regulator consists of transistor Q1, reference resistor R1, sensing resistors R2 and R3, voltage-reference zener diode D1, and operational amplifier IC1, organized as an error amplifier The zener diode D1 provides a fixed reference voltage at the positive input to amplifier IC1. The output voltage of the supply establishes the emitter volt-age and provides a feedback voltage for the negative terminal of the amplifier IC1, The equation for the regulated output voltage is Vreg=Vref(1+R1/R2)



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