This is a design circuit for precision high voltage power supply. This circuit is built by LM317 that is a regulator IC. This is the figure of the circuit.
How is the circuit work? An LM329B 6.9V zener reference has been stacked in series with the LM317’s internal reference. Both improves temperature stability, since the LM329B has a guaranteed TC of ±20 ppm/°C, and improves regulation, because more loop gain is available from the LM317. These techniques can be extended for higher output voltages and/or currents by either using better high voltage transistors or cascoding or paralleling (with appropriate emitter ballasting resistors) several transistors. The output short circuit current, determined by R3, must be within Q2’s safe area of operation so that secondary breakdown cannot occur. [Circuit source: National Semiconductor Notes].
How is the circuit work? An LM329B 6.9V zener reference has been stacked in series with the LM317’s internal reference. Both improves temperature stability, since the LM329B has a guaranteed TC of ±20 ppm/°C, and improves regulation, because more loop gain is available from the LM317. These techniques can be extended for higher output voltages and/or currents by either using better high voltage transistors or cascoding or paralleling (with appropriate emitter ballasting resistors) several transistors. The output short circuit current, determined by R3, must be within Q2’s safe area of operation so that secondary breakdown cannot occur. [Circuit source: National Semiconductor Notes].
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