Mindray Passport 5-Lead, Service Manual

Page: 210 / 544

Block Diagrams Theory of Operation
2 - 8 0070-00-0420 Passport 5-Lead, 5L, LT, XG Service Manual
2.2.1 Interconnect Board
Overview
The Passport Interconnect module is a hardware interface which provides the physical
connection between the patient connected cables, and the preamplifiers and signal
conditioning circuitry of the Front End Module. It incorporates ESD and defibrillator voltage
suppression circuitry, along with spark-gap connection to non-isolated system common.
FIGURE 2-5 Interconnect Board Block Diagram
Detail
Refer to the block diagram (Figure 2-5 on page 2-8), and complete circuit schematics, while
reading the following operation description.
The Interconnect Board can be viewed simply as the hardware connection between the
monitors external patient connectors for ECG, respiration, invasive pressure, and
temperature, and the internal signal processing circuitry. As it does this, it also provides high
voltage transient suppression.
ECG
Connection to the patient is made by ECGRA, ECGLA, ECGRL, ECGLL, and ECGC, via P3, a
standard ECG connector. Transient high voltage suppression is provided by R1, R2, R3, R9,
R10, CR1, CR2, CR3, CR10, and CR11. The resistors act as current limiting devices, while
the bidirectional transorbs limit the output signal voltages of RA, LA, RL, LL, and C, to 200
volts differential to “Shield” potential. “Shield” is ultimately connected to isolated ground on
the Front End Module.
ECGRA
ECGLA
ECGLL
ECGRL
ECGC
CShield
+IN
-IN
+OUT P1
-OUT P1
Shield
+IN
-IN
+OUT P2
-OUT P2
Shield
TIP
RING
SLEEVE
SLEEVE
RING
TIP
Shield
RRA
RLA
RA
LA
LL
RL
C
+IN
+OUT P1
-OUT P1
+OUT P2
-OUT P2
-IN
Transient Voltage
Suppression
Transient Voltage
Suppression
Transient Voltage
Suppression
Transient Voltage
Suppression
ESU Filter
Controlled
High Voltage
Discharge
Path