Philips M3921A, Руководство по обслуживанию

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Theory of Operation and System Architecture
Chapter 10 - Training Program 119
Theory of Operation and System Architecture
General
This section contains a high level overview of the theory of operation of the
major functional modules of the monitor. Philips service providers perform
Bench Repair at the assembly level. For this purpose, they should review this
high level information.
Anyone wishing to perform component level repairs should review the
detailed information provided in the
Concepts Guide .
Please be aware that Philips only stocks assembly level parts.
System Overview - A1
This section contains a system overview for the A1 monitor, including the
overall block diagram, power supply, isolated front end, NiBP control, the
SpO2 processing module, and microcontroller.
Block Diagram - A1
The monitor contains an isolated front-end section, powered by an isolated
power supply, and in which the signals from SpO
2
, temperature, and ECG
sensors are processed (see Figure 1).
The plastic tubing provides sufficient isolation for signals from the cuff in
NiBP monitoring.
A single A/D converter is used to digitize processed temperature, NiBP, and
ECG inputs; the SpO
2
module produces digitized data.
A microcontroller, Intel 386, requests and receives instructions from a flash
memory. The processor has a 16-bit data bus, and uses 19 of the 24-bit
address bus. These, and eight control signals, are used to read and write to the
DRAM, flash memory, UART, and FPGA (programmable gate array). Other
interface connections are made through the I/O port signals, timer signals, and
interrupt signals.
The FPGA provides signals for control and data to the LCD. Bias voltage and
backlight power for the LCD are provided by the power supply section. The
FPGA processes front-panel button and A1 wheel operations.
Circuit details for these blocks are contained in the Concepts Guide .