Specifications

Appendix B
Sensor Circuits
Figure B-6 shows a block diagram for the sensor circuits. Detection of any excessive
printhead temperature causes the TEMP2 signal to be sent directly to the CPU.
Other signals, such as the CRHOhJE signal, pass through each low pass filter before
reaching the CPU. Terminals P50 to P55 on the CPU are used for the A/D
converter.
The Vref circuit generates the A/D converter reference voltage Vref.
CRHome
Printhead
Seneor Circuit
TMP2
---- - - ------_______
+5 v
I
CPU (IC21)
-, P50 VREF 4
Vref Circuit
P51
0.022 j CR;;;;;
+
GAP, P34
o------------______’
PE-2
---, P31
Sensor Circuit
LEVER
- - _ _ - - - -
1 Head Drive Voltage
(+35 V) Monitor Circuit
lQ-
c ,
2&
__ _ ___ _’
GAPGAP
Sensor CircuitSensor Circuit
- - - - _ - _ _ - - - - _ - _ _
zz
CC
lo- lo-
g 2Q+ 5 2Q+
Figure B-6. Sensor Circuit Block Diagram
Epson LQ-570+/1 070+
B-11