User and Programming Manual - Rev H
California Instruments
May 2000
P Series
20
5. Principle of Operation
5.1 General
An explanation of the circuits in the AC Source is given in this section. Refer to Figure 5-1 for
a block diagram of the system.
AC
Power Factor
DC - DC
DC - AC
AC
Input
Corrector (PFC)
Converter
Converter
Output
Oscillator &
Controls
Figure 5-1: AC Source block diagram
5.2 Overall Description
The AC input is fed to the power factor correction, boost type converter. The converter steps
the voltage to 385 VDC while drawing only sinusoidal current from the input power line.
The DC to DC converter provides isolation and changes the voltage to 250 VDC or 400 VDC
depending on whether the low output range or high output range is selected.
The DC to AC converter develops an AC sine wave voltage at the output range, frequency and
amplitude programmed by the oscillator.
The oscillator board provides the reference signal to the DC to AC converter and has the front
panel shuttles and switches to control and view the setting of voltage, frequency and current
limit.
