Spot Vital Signs LXi Service Manual - Frank's Hospital Workshop

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Technical Overview
System Description
Battery System
Battery Charger
The Spot Vital Signs LXi automatically measures systolic and diastolic pressure (excluding
neonates), pulse rate, temperature (oral, adult axillary, pediatric axillary, rectal, and ear),
and pulse oximetry (SpO 2 ) as well as calculates Mean Arterial Pressure (MAP).
Furthermore, Spot Vital Signs LXi allows the entry of height, weight, respiration rate, and
pain level. Spot Vital Signs LXi also calculates Body Mass Index (BMI) following height and
weight entry.
The device is intended to be used by clinicians and medically qualified personnel. It is
available for sale only upon the order of a physician or licensed health care provider.
Refer to the Spot Vital Signs LXi Directions for Use manual for complete information.
Spot LXi includes a 6 Volt, 6 amp-hour sealed lead-acid battery that supplies all power to
the device. An external power supply charges the battery. The battery is always on-line
(floated) rather than switching out when attached to the external power supply.
Spot LXi uses a fuse and a shunt diode for protection against reverse battery connections.
The fuse is located on the main board in the negative battery line and a reverse battery
connection causes it to blow and require repair. The negative line location is more likely to
short the battery (+) wire to ground than short the battery (-) wire to the VBUS node.
Provides two levels of power to fast-charge or to float the battery at fixed voltages using
software control. The fast-charge level rapidly brings the battery up to near-full capacity (7
Volts) using software to not overcharge the battery. The float level, set per the
manufacturer’s recommendation, slowly tops-off the battery and can stay on indefinitely.
“CPU I/O” Power Supply
Provides power to the I/O pins of the DragonBall MPU and the attached peripheral IC’s.
The nominal voltage is set to a value of 3.15 Volts so that both the 3.0 Volt MPU and 3.3
Volts peripherals can operate within specifications. Spot LXi uses buck switching topology
for efficiency and an on-off power latch directly controls the power supply.
CPU Core Power Supply
Powers the MPU core only and operates at the recommended Dragonball voltage range
of 1.8 +/- 0.1 Volts; 2.0 Volts absolute max.
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