Chapter 3
Theory of Operation
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BiPAP Vision Service Manual © Respironics, Inc.
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3.1 PSS Board
The PSS board (Figure 3-3) supplies the MC, PC, and DC boards with the
correct DC supply voltage. Safety features designed into the circuitry include
an overvoltage disconnect, low voltage supply detect, and line loss detect.
Other features include power on indicator voltage, circulation fan power, and
an on/off switch connection.
Figure 3-3: PSS Block Diagram
3.1.1
Input Range
The BiPAP Vision can operate with an input of 100, 120, 230, or 240 VAC
(±10%) depending on the model.
3.1.2
DC Supply
The output DC supply is fused at 30 amps (A) and delivers between 20.6 VDC
and 35 VDC with a maximum ripple of 1 Vpp (peak-to-peak voltage) to the MC,
PC, and DC boards.
PSS
operating
circuitry
Bulksupply (J2) to
MC, DS, PC
AC input (J1)
On/off
switch (J7)
AC power
indicator (J5)
Circulation fan
(J6) (J4)*
Line loss
detect
Overvoltage
disconnect
To MC AC fail
monitor (J2)
Low
bulksupply
detect
Circulation fan current
sense (J8 HW),
PC (J12)
* For fans with older style 2-pin connector. Note that cur-
rent version of PSS board still includes the J4 header.
HW = hard-wired
