4.7.2 Output Voltages
The power supply makes several output voltages:
CAPACITIVE LOADING
OUTPUT
VOLTAGE
“TOTAL”
REGULATION
BAND
Min.
Load
Typ.
Load
Max.
Load
Minimum
Capacitance
Maximum
Capacitance
+5.0Vana
(RS)
+/-1% 0.1A 4.0A 4.2A
1200µF 1800µF
-5.0V (RS) +/-1% 1.0A 5.0A 5.25A
1200µF 1600µF
+9.0V +/-2% 0.1A 0.4A 0.5A
330µF 390µF
+2.5V +/-5% 0.1A 1.0A 1.4A
1400µF 2000µF
+12.0Vana +/-1% 0.1A 0.16A 1.16A
330µF 560µF
-12.0V +/-2% 0.1A 0.62A 1.7A
330µF 560µF
+5.0Vdig +/-5% 0.1A 3.1A 5.5A
2400µF 10000µF
+12Vdig +/-5% 0.1A 1.0A 1.24A
500µF 1000µF
3.3V +/-5% 0.1A 2.0A 3.0A 4000uF 6000uF
5.0V(stand) +/-5% 0.1A 0.1A 1.0A
Note: RS represent Remote Sense.
4.7.3 Basic Operation
The power supply utilizes 5 converter, 5 synchronous step- down switching
regulator and step-down switching regulator.
4.7.3.1 Pre-converter
Power Factor Correction (PFC) circuit. It uses a Critical Mode Boost
Converter topology switching and using MosFETs as the primary switches.
The output of the PFC Converter is regulated to 385VDC.
4.7.3.2 Main Converter
The converters are like dual-switch half-bridge converters switching at
approximately 88KHz and utilizing the module integrated controller and two
MosFETs as the primary switches. Output is regulated using a post
switching regulation scheme. The output has its own raw voltage provided
on its own separate winding on the transformers. The output is regulated to
24V secondary bus voltage,.
4.7.3.3 House Keeping Power Supply
It is a fly back converter switching at approximately 80 kHz. The bias supply
also provides other voltages for internal housekeeping. The bias supply is
“ON” whenever AC is present. +5VSB is provided from an
step-down
switching regulator
.
4.7.3.4 +5VDIG and 3.3V DC/DC(
Daughter Board)
Dual 2-phase
synchronous step-down switching regulator is used for the
+5Vdig and +3.3V supply.
Theory of Operation 4-17
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