Datex-Ohmeda S/5 Compact Anesthesia and Compact Critical Care Monitors
6
Document no. M1144958-001
PMB CPU unit
The CPU unit controls all other functions of the board. The functions include:
• Battery current monitoring
• Battery capacity calculations
• Battery temperature monitoring
• Battery charger control
• Frame fan voltage control
• Level-change of recorder serial line signals
• Module power supply measurements (voltages & input current)
• Module power supply start-up and shutdown
• Power path management (choosing the correct supply source)
• Monitor start-up and shutdown control
PMB +5V supply
This unit provides the PMB CPU and other PMB electronics +5V power supply. Input either
internal battery or AC/DC output, output +5V.
Battery charger supply
The charger generates the desired charge current for the batteries from the AC/DC output
voltage. At fast charge rate the current is 1A, at timed charge the current is 500mA for 1/3
rd
of
the time and at trickle charge rate the current is 500mA for 7/500
th
of the time. The charge rate
is controlled by the CPU block.
Power path switching electronics
The power source to be used (batteries or AC/DC output) is chosen initially by a ‘power path
controller’ inside this block. The CPU unit has full control over the power path management
after the initial choice is made at start-up. In addition to the power path, the charge current
path is also chosen by the CPU and driven by the power path controller.
WARNING For as long as the AC/DC unit or either one of the two internal batteries is
connected, the open metal surfaces in this area contain approximately 15V
voltages. An accidential touch of a screwdriver or anything else conductive
may short-circuit the power lines and destroy PMB electronics.
Frame fan power supply
This unit drives the fan (mounted in the side frame unit). It is controlled by the CPU unit, and
driven according to AC/DC current information and frame temperature.
2.4 Module motherboard
The module motherboard routes signals from the PMB to the module slots. Signals include
power supplies and module data buses.
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