Covidien Valleylab LS10 Service Manual page 64

Functional Overview
Footswitch
The Host processor needs to detect the activation of the foot switch when using certain
instruments. Since the foot switch is in contact with the user, the switch detection
circuitry is isolated from the Host processor.
Fan
The Host processor can both control the speed of the fan and sense the speed of the fan.
The air flow of the fan is first directed over the H-bridge FETs, their drivers, and their heat
sinks. The air flow proceeds to the RF inductor and the RF transformer. Other than the
commercial AC/DC power supply, these components comprise the main source of heat
generation in the generator.
ECG Blanking
The ECG blanking port is controlled by the Host processor. It is activated before RF
energy is applied to tissue and deactivated after the cessation of energy application. It
can be used to protect ECG equipment if that equipment is connected to the patient, or
it can be used to control an evacuation fan. The relay contacts will handle up to 12 volts,
AC/DC, and up to 0.2 amps.
USB Port
The USB port is configured as a serial port into the Host processor. The Host processor
can communicate over this port to any PC that has its own USB port configured as a
serial port. There is a USB to serial port converter on the generator PCBA. The Host
processor interfaces to this converter over a normal serial port.
AC to DC Power Supply
The AC/DC power supply is a purchased part. It converts normal power to 48 volts DC
and can supply up to 8.3 amps. Without fan cooling, this supply cannot continuously
supply the 8.3 amps but the generator only draws that amount of current for short
periods of time.
Power Entry Module
The power entry module is located on the rear of the generator. It provides the
connection for a modular power cord. The module also contains the power fuses for the
generator.
4-6 Valleylab LS10, LS Series Single Channel Vessel Sealing Generator Service Manual