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Chapter4 Working Principle and Structural Characteristics
4.1 Working principle and its block diagram
4.1.1 The power supply unit
(
1
)
Principle of power supply
The switching power supply provides +24V working voltage for the thermal print head,
provides constant voltage current limiting charging for the rechargeable lithium battery in the
device through the DC-DC circuit, and generates +5V and +12V voltage through the power
conversion to supply power to the corresponding modules. At the same time, the lithium battery
in the device can independently satisfy working requirements of each module in the device
through the buck-boost circuit.
(
2
)
Principle block diagram is shown in Figure4-1.
Figure4-1 Block diagram of power principle
Note: The principle block diagram and component list are only available to service
stations or maintenance personnel designated by our company.
4.1.2 Signal acquisition unit
The signal acquisition unit uses a floating setting, which is a signal acquisition and
processing system, including analog circuit part and A/D conversion (with sampling accuracy of
24 bits) and data processing part. The analog circuit consists of signal following, amplification,
anti-aliasing low-pass filtering, lead-off detection and overload detection. CPU system is
responsible for coordinating the work of each circuit such as the A/D converter, the lead-off
detection circuit and the overload detection circuit, in order to achieve signal acquisition,
processing, and lead-off detection. Control information and A/D conversion and data acquisition
between the floating circuit and the solid circuit are transmitted through the optoelectronic
DC- DC conver si on
Bat t er y
Di spl ay uni t
Ther mal pr i nt
head
Swi t chi ng power
suppl y
DC- DC conver si on
Acqui si t i on uni t
Cont r ol uni t
Mot or
AC100~240V
50/60Hz
+24V
+
14
.8
V
C
h
a
r
g
i
n
g
+5V
+12V
+14.8V
+14.8V
Содержание 1200G ECG
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