R01UH0823EJ0100 Rev.1.00
Page 1514 of 1823
Jul 31, 2019
RX23W Group
43. Capacitive Touch Sensing Unit (CTSU)
Figure 43.6
Discharging Operation (m = 2, 3, 4, 7, 8, 12, 13, 22, 23, 27, 30, 35)
Figure 43.7
Change in Measured Value When Finger is Touching and Not Touching
SW1
SW2
ICO
Switched
capacitor filter
i = fCV
Counter
Sensor drive pulse
LPF
-
+
VCC
TSCAP
Sensor
(electrode)
Control
current
Reference
electric
potential
Power
supply
TSm
Number of counts
Time
0
Touching
Not touching
Touch is determined
based on the difference
Sensor drive pulse generated