User's Manual

68P80801H45-1 1/20/2002 7
EBTS System Manual - Vol 2 DC Power Supply
DC Power Supply for QUAD Channel Base Radios
QUAD Channel DC Power Supply Theory of Operation
Table 7 briefly describes the basic DC Power Supply circuitry. Figure 5 shows the
functional block diagrams for the DC Power Supply.
Table 7 DC Power Supply Circuitry
Circuit Description
Input Circuit Routes input current from the DC power input cable through the
high current printed circuit edge connector, EMI filter, panel mounted
combination circuit breaker, and on/off switch
Startup Inverter
Circuitry
Provides VDC for power supply circuitry during initial power-up
Main Inverter Circuitry Consists of a switching-type power supply to generate the +28.6 VDC
supply voltage
Temperature Protection The Power Supply contains a built-in cooling fan that runs whenever
the supply is powered on. The supply shuts down if the temperature
exceeds a preset threshold
+14.2 VDC Secondary
Converter Circuitry
Consists of a switching-type power supply to generate the +14.2 VDC
supply voltage
+3.3 VDC Secondary
Converter Circuitry
Consists of a switching-type power supply to generate the +3.3 VDC
supply voltage
Clock Generator
Circuitry
Generates the 267 kHz and 133 kHz clock signals used by the pulse
width modulators in the four inverter circuits
Address Decode,
Memory, & A/D
Converter
Serves as the main interface between A/D on the Power Supply and
the BRC via the SPI bus