Xtreme Power Conversion Corporation
G90 Service Manual
Page 16
Uninterruptible Power Supply
As shown in functional diagram, the power stage consists of charger, DC power supply, DC-DC converter, inverter
and output filter.
Charger Sub-System:
The purpose of charger is to charge and to maintain the batteries at full charged condition. Refer to circuit
diagram, the voltage fly back switching power supply provides a constant DC voltage (13.65Vdc/PCS battery) for
batteries. Besides providing constant voltage, the power supply also limits the current flowing into batteries and
therefore protects and prolongs the life time of charged batteries.
Note: For detail circuit diagram and key waveforms and values, see Annexures-circuit diagram.
Auxiliary Power Supply Sub-System:
The input of the auxiliary power supply is connected to the battery bus, i.e., the output of the charger. The
output of auxiliary power supplies pr12 Vdc for the bias supply of IC’s working voltage and the fan(s)
voltage. The DC power supply works only when the 12 Vdc regulator supplies Vcc to its control IC. To have proper
operation of 12 Vdc regulators, its input power is controlled by the switch as indicated in circuit diagram.
Block Diagram for UPS
Charger Circuit Diagram