Circuit Analysis; Functional Overview; Ac Input; Figure S-2: Npb-190 Functional Block Diagram - Nellcor NPB-190 Service Manual

S3

CIRCUIT ANALYSIS

S4

FUNCTIONAL OVERVIEW

S5

AC INPUT

The following paragraphs discuss the operation of each of the printed circuit
boards within the NPB-190 pulse oximeter. (Refer to the appropriate schematic
diagram at the end of this supplement, as necessary.)
The monitor functional block diagram is shown in Figure S4-1. Most of the
functions of the NPB-190 are performed on the UIF PCB. Functions on the UIF
PCB include the SPO
2
of the NPB-190 are the Power Entry Module (PEM), Power Supply, and the
Display PCB.
The Display module consists of the LED display and the Membrane Panel.
Contained on the Membrane Panel are enunciators and push buttons, allowing
the user to access information and to select various available parameters. The
Display PCB contains; SpO
driver circuits.
Power
Entry
Fuses
Module
Battery
Alarm Speaker
Serial port
UIF PCB

Figure S-2: NPB-190 Functional Block Diagram

A selector switch on the back of the NPB-190 allows the user to connect the
monitor to AC power ranging from 100 VAC to 240 VAC. The switch has two
positions, one for 100 VAC through 120 VAC and one for 200 VAC through 240
VAC. Verify that the switch selection matches the AC power at your location
before plugging the monitor into an AC outlet.
AC power enters the NPB-190 through the Power Entry Module (PEM). Both
the Line and Neutral lines are protected by a 0.5 amp fuse. These user-accessible
fuses are located in a fuse drawer, which is part of the PEM located on the back
of the monitor.
module, PIC, CPU, and Memory. Other key components
heart rate, and Blip Bar LEDs, and their associated
2,
Power Supply
Battery DC
Charger Supply
PIC
Flash ROM
64K
Technical Supplement
Membrane
On/Off Switch
Panel
LED Display
EEPROM
80196
CPU
System RAM
Patient
SPO Module
2
Connection
S-3