Lcd; Irda - Nellcor OxiMax NPB-40 Service Manual

LCD

IrDA

Power Supply
Power Supply Monitoring
NPB-40
The liquid crystal display (LCD) is driven by the CPU. The LCD displays the
patient's %SpO and pulse rate. The LCD also displays icons indicating the status
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and functions of the NPB-40. Refer to the NPB-40 Operator's manual for a
description of the icons.
The IrDA (Infrared Data Association) is an industry standard for infrared
communications. The IrDA receives information from the CPU, converts it, and
sends it to an external printer. The external printer communicates with the IrDA.
Refer to the printer manual for more information.
The user interface PCB power supply receives power from the SpO
supply. The power supply provides a regulated 3.0 volts DC to the CPU.
The power supply outputs are monitored by the power monitoring function to
ensure stability. The power supply monitoring circuit sends a reset signal to the
watchdog circuits to shut down the NPB-40 when voltages are out of tolerance.
The power supply monitoring circuit monitors the battery output voltage and shuts
down the NPB-40 when the battery voltage is critically low. The circuit provides
the low battery signal.
Technical Discussion
PCB power
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