Service manual

CARDELL MONITOR SERVICE MANUAL
21-02-0286 REV. 02 05/09
56
+3.3V TP2 Chip I/O supply voltage for the DSP Controller (U20).
The +5 volts output of the switching regulator (U1) goes into a voltage regulator (U2) to supply
the +3.3 volts.
+2.5V TP3 Core operating voltage for the DSP Controller (U20).
The +5 volts output of the switching regulator (U1) goes into a voltage regulator (U3) to supply
the +2.5 volts.
+5V_ISO2 TP8 Isolated power supply for the SpO
2
circuit.
The +5 volts output of the switching regulator (U1) goes into a dc-dc converter (U9) to supply +7
volts. The converter provides an isolation voltage of 2.5KV. The dc-dc converter is turned on
and off by the DSP controller (U20) and transistor (Q7). The output of the converter feeds a +5
volt regulator (U22) that provides voltage for the SpO
2
board.
+5VCRG TP6 Power supply for the Battery Charger.
The DC input goes into a voltage regulator (U7) to supply the +5 volts.
+VND TP4 Power supply for the Blood Pressure pump.
The DC input or the Battery input, if there is no DC present, goes into a voltage regulator (U27)
to supply the +6 volts. The voltage regulator is turned on and off by the DSP controller (U20)
and transistors (Q16 and Q17).
BATTERY CHARGER
The battery charging is controlled by U8.
SUPERVISOR MICROCONTROLLER
The Microchip PIC16F73 (U5) is the supervisor of the Main Control Board. The controller has
4K of program flash, 192 bytes of data memory and operates from an external 153.6KHz
crystal. The Microcontroller has 22 I/O’s, 3 timers, 2 PWM/capture/compare modules, UART,
SPI, and five (5) 8bit analog-to-digital channels.
Indicator LED’s
LED1 is the power/low battery/charging indicator that is controlled by an output port of the
Microcontroller (U5).
Power Smart Module
The Power Smart Module option comes into the Main Control Board at J2 (pins 2 and 3). The
Power Smart Module is read by the Supervisor (U5 pins 25 and 26) then sent to the DSP (U20)
thru the SPI port.
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