3-3
3. ELECTRONICS
EO18-33014
(Revision Date: Jan. 29, 2004)
3.3 DRIVER PC BOARD
(7) Print Head Circuit
This circuit sends print data to the print head and outputs the strobe signals, enable signals, etc.
The termistor signal output from the print head is transferred to the A/D converter of the CPU. The CPU uses
this signal to control the print tone by detecting the print head temperature. This circuit also checks the voltage
supplied to the print head and the print head broken element.
(8) Interface Circuit
To CN103 on the CPU PC board, various interface devices used to interface with the host or handy terminal
are connected. The interface types are different depending on the models.
- RS-232C interface: GH20 model
- Bluetooth interface: GH30 model
- Wireless LAN: GH40 model
The IrDA driver/receiver is installed on the CPU PC board of the all models as standard,
3.3 DRIVER PC BOARD
This PC board, including the stepping motor driver, generator IC, etc, controls the stepping motor and
generates the voltages from the battery supply voltage.
(1) Stepping Motor Driver
This circuit controls the stepping motor connected to Connector 2. Using the PM1 and PM2 signals output
from the CPU PC board, it generates the PMA1, PMA2, PMB1, and PMB2 stepping motor drive signals.
Also, the PMEN signal output from the PLD on the CPU PC board is used as the driver's enable signal.
(2) Power Supply Circuit
This circuit generates the operating voltage for the logic ICs, print head, stepping motor, etc. from the voltage
VM (DC 7.4V) that is supplied from the Li-ion battery connected to Connector 3.
The 3.3V is used to operate the CPU, PLD, Flash ROM, SDRAM, etc. 5VB (5V) is used to operate the
peripherals and control circuits, such as, the stepping motor driver, feed gap/black mark sensor, strip/batch
sensor, print head (signal), etc.
The VH voltage is used as the operating voltage for the print head and stepping motor.
Also, this circuit protects itself when an overcurrent of the battery or an overvoltage is detected by cutting off
the circuit.
