Power Supply Theory; A15 Preregulator - Agilent Technologies 8719ET Service Manual

Theory of Operation

Power Supply Theory

Power Supply Theory
The power supply functional group consists of the A15 preregulator and the A8 post
regulator. These two assemblies comprise a switching power supply that provides
regulated dc voltages to power all assemblies in the analyzer. The A15 preregulator is
enclosed in a casting at the rear of the instrument behind the display. It is connected to the
A8 post regulator by a wire bus A15W1.
power supply group.
Figure 12-2 Power Supply Functional Group, Simplified Block Diagram

A15 Preregulator

The A15 preregulator steps down and rectifies the line voltage. It provides a fully
regulated +5 V digital supply, and several preregulated voltages that go to the A8 post
regulator assembly for additional regulation.
The A15 preregulator assembly includes the line power module, a 60 kHz switching
preregulator, and overvoltage protection for the +5 V digital supply. It provides LEDs,
visible from the rear of the instrument, to indicate either normal or shutdown status.
12-6
Figure 12-2 is a simplified block diagram of the
8719ET/20ET/22ET
8719ES/20ES/22ES
RF Network Analyzers
Service Guide