Platinum Z5 CD, Manual

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888-2408-002 4-5
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
Figure 4-2
Exciter Status Screen
[HOME, STATUS D,C]
4.3.2 IPA
The IPA amplifier and/or module is identical to any one of the PA modules. This
allows a PA module to be used in place of a failed IPA. The standard IPA
configuration includes dual IPA amplifiers, used in a main/alternate configuration
(in other words only one is used at a time).In this configuration the IPA Module is
identical to a PA module. If one of the IPA amplifiers fails, the controller will
automatically switch to the second IPA with a minimal interruption of service. For a
detailed explanation of the RF amplifier operation refer to the paragraph “Power
Amplifier” later in this section.
4.3.2.1 IPA Power Output
The power output of the IPA determines the power output of the transmitter and is
varied by changing the gate bias on the IPA amplifiers MOSFETs. The gate bias for
the IPA is adjusted by the controller, specifically the Master Controller Board, using
the front panel “POWER” Raise and Lower controls.
4.3.2.2 IPA Power Supply
The IPA power supply is +52 volts and is diode or’ed from both of the PA power
supplies for redundancy. The +52Vdc is connected to the IPA(s) via the IPA
Backplane Board.
4.3.3 IPA Backplane Board
Refer to the IPA Backplane schematic for the following. The IPA module plugs into
the IPA Backplane Board. This board interfaces all inputs and outputs for the IPA
module. It is also responsible for:
•
Main/Alternate exciter switching (only active with optional dual exciter configu-
ration).
•
Main/Alternate IPA switching (active with standard, dual IPA configuration).
•
Monitoring of IPA temperature, voltage, current and forward power.