Section 9: Technical Supplement; Introduction; Functional Overview; Figure 9-1: Overall Block Diagram - Mallinckrodt Nellcor N-20PA Service Manual

SECTION 9: TECHNICAL SUPPLEMENT

9.1

INTRODUCTION

9.2

FUNCTIONAL OVERVIEW

9-1 Introduction
9-2 Functional Overview
9-3 Definition of Terms
9-4 Overall Block Diagram
9-5 SpO Analog Circuitry
2
9-6 Digital Circuitry
9-7 Circuitry Illustrations
This Technical Supplement provides the reader with a discussion of the N-20PA
circuits. This discussion is supported with applicable illustrations, including
graphics that have been placed on reverse-fold pages so they can be easily
referenced while reading the text. The foldout graphics and schematics are
located at the end of this supplement.
The N-20PA consists of three main components:
• The N-20PA main printed circuit board (PCB)
• The N-20PA auxiliary PCB
• The N-20PA flex circuit
The relationship between these components and their interconnection is
illustrated in the overall block diagram (Figure 9-1). The main component
circuitry has been divided into the following subsections:
Patient
sensor
SpO 2 analog
Microprocessor
Memory
Display control
Sensors: temperature
PROM
Power supply
Printer interface
Display control
Audio beeper
Batteries
6 VDC
Real-
clock

Figure 9-1: Overall Block Diagram

Main PCB
ambient light
battery voltage
Measure
button
20-Pin headers
Auxiliary PCB
Flex
connectors
Check
time battery
button
Display
backlight
Printer
Printer
flex circuit
9-1