LIFEPAK 20/20e Defibrillator/Monitor
Device Description
Functional Description
(continued)
A02 Patient Parameter
PCB
(continued)
■
ECG Pre-Amplifier
— The ECG pre-amplifier performs the function of
patient-isolation, low-pass bandwidth filtering, and ECG sampling through
the analog-to-digital conversion (ADC) for the ECG signal received through
the W06 ECG Connector. Digital signals are passed over the isolation barrier
into the DSP for additional signal processing. The ECG pre-amplifier section
supports either 3-wire or 5-wire ECG input.
A03 Power Module
is primarily responsible for selecting the best available
source to power the rest of the modules/PCBs in the system from the available
power sources. A microcontroller with built-in memory makes up the CPU.
Communication is provided to the A04 Therapy PCB through a serial interface.
The major subsystems on the A03 Power Module are as follows:
■
Power Supplies
— The A03 Power Module uses ORed_VBatt (battery
voltage ORed with dc power from the A09 AC Power Supply Module) to
originate two power supply voltages for use throughout the PCB as follows:
– +5 V logic power to drive the CPU microcontroller and memory
– + 3.3 V analog power to drive the power pump for the RS-232 driver
circuits
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