Instruction manual

4 THEORY OF OPERATION
4.1 GENERAL
1. The BOS/S THEORY OF OPERATION shall describe the following major sections.
2. A200 Output Stage
3. A100 Control Board
4. Simplified Schematic, Voltage Channel
5. Simplified Schematic, Current Channel
6. Voltage Channel Signal Flow
7. Current Channel Signal Flow
8. ±10 VDC Precision Reference
9. Active Limit Circuitry
4.2 A200 POWER AMPLIFIER BOARD
The A200 PCB’s function is to provide power amplification of the Current or Voltage
Mode Signals which are provided by the A100 PCB. The power amplifier is a Quasi
Push/Pull Type Amplifier which directly controls all output functions. The number of
A200 PCBs installed in the unit is determined by the maximum output of the unit.
The A200 assembly contains the heatsinks, buffer amp and output power transistors.
The input signal to the A200 PCB is provided by the A100 PCB. The signa; is applied
to two sets of power amplifiers. One set of power amplifiers causes the output to go
positive with respect to the output common. The other set of amplifiers caused the
output to go negative. The local feedback on the assembly determines the magnitude
of the drive signal. See Figure 4.3.1.
4.3 A100 CONTROL BOARD
The A100 Board contains all vital controls for the BOS/S. It contains circuitry for
switching between Voltage and Current Modes, Internal and External Control, Voltage
and Current Limiting, IEEE and RS232 inputs. It also contains the error amplifiers for
both the Voltage and Current Control and all of the associated feedback components.
The signal flow can be seen for both the Voltage and Current Mode from the simplified
schematics in Figures 4.3.1 and 4.3.2.
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83-469-001 Rev. B