2/Theory of Operation
2-10 1503-0151-000 3/27/97
Power Supply Assembly
The power supply board encompasses two functional blocks: power supply and
external interface.
Power Supply
The power supply is divided into three stages,
• ac to dc Conversion
• dc Step-down Regulator and Battery Charger
• Multiple Output dc to dc Converter
Functional Specifications
• Autoranging input 85-132 and 190-270 Vac, 47-63 Hz, 54.5 VA.
• Output 5V for digital circuit, 5.5V for electromechanical actuators,
14.5 V for EL display and
±
15V for analog circuits.
• Approval to UL-544, CSA, VDE, IEC-601 and other applicable med-
ical product standards.
• Leakage current under 300 micro Amps @ 132 Vac, 60 Hz.
• Output short-circuit, over-voltage protection, with automatic recov-
ery after removal of fault.
• Battery under-voltage disconnect function protects charging bad
cell.
• Battery under-voltage cutoff function protects over-discharging.
• 30 minute battery backup operation under normal application.
Power Requirements
• Maximum input requirement: 54.5 VA ac
• Maximum output capacity: 26.7 W dc
Heat generation
The maximum heat generated from the power supply is 27.8 Watts.
ac to dc Conversion
Input Voltage ranges from 85 to 132 and 190 Vac to 270 Vac, 47 to 63 Hz enters
the unit via power entry module with a medical grade line filter. This filtered output
is converted to dc voltage via a toroidal isolation transformer and bridge rectifier.
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