AR 10U1000, Руководство по эксплуатации и обслуживанию

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Model 10U1000
18 Rev B
3.2.2 A2 10W Module (Schematic 10041561)
The 10W Module consists of RF matching circuits, an RF transistor, a DC current control circuit, a DC
switching circuit, and a fault detection circuit.
The RF input is fed to a balun transformer (T1). The push-pull output signal of the balun transformer is
connected to the gates of Q1 and Q2. The drains of Q1 and Q2 are connected to a balun transformer (T2).
The RF transistors, Q1 and Q2, have approximately 28 VDC applied to the drains at 1.5A each. The RF stage
has approximately 14 dB of gain and an output compression point of 10W or greater from final amplifiers.
Voltage comparator U1 senses the presence of the –8 VDC. The output of U1 is high if the –8V supply is –
5.5 or less. The output of U1 pulls low when the –8 volts is present turning on Mosfet Q3 which supplies the
DC voltages to the drains of Q1 and Q2.
The current through Q1 and Q2 is monitored by U2. The output of U2 is fed to an op amp (U5) which has a
reference voltage on the non-inverting input. It compares the output of U2 to the reference voltage and
generates an error signal to vary the gate voltage of the RF transistors Q1 and Q2 which controls the drain
current.
U3 is a positive 5V regulator. It supplies DC to the current sense circuit, U2, the op amp, U5, and the fault
detection circuit, U6. SW1 is a thermal switch. It closes at a heat sink temperature of approximately 55
o
C to
protect the module in the event of an over-temperature condition.
3.3 POWER SUPPLIES (PS1, PS2)
Power supply PS1 supplies a +5VDC housekeeping supply for the control system assemblies A4
Control/Fault Board and A5 Interface Board.
PS1 also supplies -15 VDC at 2.5 amps. PS1 is a switching supply that automatically sets the AC input
circuits to the correct connections for the line voltage 100-240 VAC input ranges 47-440 Hz.
The -15 VDC at 2.5 amp power supply is fed to the A10 Voltage Regulator board, A1 Pre-Amp, and A2 10
Watt Module.
Power Supply PS2 is a single output supply which pr28VDC to the final module and to the A10
Voltage Regulator board. Primary AC circuit protection is provided by the circuit breaker in the Power Entry
Module.