Service manual

CARDELL MONITOR SERVICE MANUAL
21-02-0286 REV. 02 05/09
55
THEORY OF OPERATION
The CARDELL Monitor’s Main Control Board provides the following functions for the operation
of the monitor.
• Power Supplies
• Battery Charger
• Supervisor Microcontroller (Microchip PIC 16F73)
1. Indicator LEDs
2. Power Smart Module
3. Power ON/OFF and Reset to Digital Signal Processor Controller
4. Monitor ON/OFF
5. Communication with Digital Signal Processor Controller
6. Monitor Battery Charger and Battery conditions
• Digital Signal Processor Controller (Motorola DSP 56F827)
1. SpO
2
Monitoring
2. Blood Pressure Monitoring
3. Keypad Monitoring
4. Indicator LEDS and Displays
5. Real-Time Clock
6. Alarms
7. Serial Interface
POWER SUPPLIES
The input to the Main Control Board comes from either the DC input (J1) or the Battery Input
(J2). A Control chip (U6) is responsible for selecting the monitor’s main power source. The DC
input always takes priority over the Battery.
Battery 7.2 Volts @ 4.0 Ahr (TP7 to TP33)
DC 12 Volts @ 28 Watts (TP28 to TP29)
There are several supplies that are generated for internal use.
+Vpic TP5 The power supply for the Microchip PIC16F73 (U5), the Supervisor of the
Main Control Board.
The DC input or the Battery input, if there is no DC present, goes into a voltage regulator (U4) to
supply the +3.3 volts.
+5V TP1 Power supply voltage for the main Analog and Digital circuitry.
The DC input or the Battery input, if there is no DC present, goes into a switching regulator (U1)
to supply +5 volts. The regulator is turned on and off by the Microcontroller (U5).
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