Start=up circuit for circuit stages with input voltages exceeding 500 V - contains capacitor charged from input voltage via high impedance potential divider, thyristor triggered via zener diode

摘要

The circuit contains a capacitor (C103) which is charged from the input voltage via a high impedance potential divider (R101,R104). The capacitor supplies a power switch (L) and regulator (R) with the required starting energy via a thyristor (T103) as soon as the capacitor has reached the required operating voltage. The thyristor is triggered by a zener-diode ((D102). The power switch and regulator are supplied with energy after start-up from a filter (F) and via a diode (D105), a resistance (R110) and the thyristor (T103). USE/ADVANTAGE - The start-up circuit has low power losses, low component costs and high operating reliability.