GE MAC 1200, Руководство по обслуживанию

Страница: 25 / 151

Revision D MAC

1200 resting ECG analysis system 2-7

2012250-095
Functional Description: PCB Control CS_CI
PCB Control CS_CI
The PCB Control CS_CI is the main board of the MAC

1200 resting ECG analysis
system. The main board accommodates the control functions of the device, except
the line power supply and the NC battery-charging controller.
Generation of Internal Power Supplies
Logic Power 5 V and +3.3 V
The processor core and the memory is a fully +3.3 V design. The interface functions
to display, to RS-232, to the printing unit and to the ECG acquisition unit are
supplied with +5 V.
Both the +3.3 V and the +5 V are generated separately by a clock-rated voltage
controller. By using the “adjustable version” of the voltage controller, both supplies
are based on the same voltage controller. The output voltage is determined by
appropriate dimensioning of the voltage divider at the feedback input of the voltage
controller.
Standby 5 VSTB and +3.3 VSTB
The standby 5VSTB supplies the ON/OFF Control, the + 3.3 VSTB
buffers the patient ECG memory when the device is turned off. Both supplies are
generated together from one low-power linear regulator with low quiescent supply
current.
Analog 12 V
+12 V is used for the heating control and temperature monitoring of the printing
unit, which requires only a current of a few milliamperes. This supply is generated
by a linear regulator with feedback input.
FPGA Power 2.5V +1.25V
+2.5 V is the auxilliary source of power and +1.25 V is the main power supply for
the FPGA internal logic. These voltages are generated by Dual Output Low Dropout
Regulator.