Bulk Voltage Regulator
Original Publication Date: 1988-Feb-01
Included in the Prior Art Database: 2005-Feb-14
This article describes a regulator circuit for transforming an AC voltage to a DC bulk voltage. The DC bulk voltage is outputted from a capacitor that is charged and discharged at a controlled rate. With reference to Fig. A, current flows through R2 and forces the zener diode D1 to break over. This provides a voltage across gate- source terminals of FET Q1 which is sufficient to initiate its turn-on. Once Q1 is turned on, the voltage across bulk capacitor C1 increases as current flows through R1, Q1 and D2. The charge on C1 increases until the voltage across it reaches a desired level. The voltage divider R3 and R4 is designed so that D3 conducts when Vbulk reaches the desired voltage level. The conduction of current through D3 produces the gate voltage required to trigger SCR Q2.