STM8T141 STMicroelectronics, STM8T141 Datasheet - Page 11

• Manufacturer Part Number: STM8T141
• Description: Single-channel capacitive sensor for touch or proximity detection with shielded sensing electrode
• Manufacturer: STMicroelectronics

STM8T141
Figure 5.
1. R
The principle of charge transfer is to charge the electrode capacitance (C
power supply. When C
C
until the voltage across the sampling capacitor C
voltage (V
number of transfer cycles composing a burst (see
Throughout this document the following naming conventions apply:
●
●
●
Figure 6.
X
to an external sampling capacitance, referred to as C
X
The charge transfer period (
subsequent transfer of the charge to C
The burst cycle duration (t
The sampling period (t
must be placed as close as possible to the STM8T device.
STM8T141
TRIP
STM8T measuring circuitry
Conversion period examples
). The change in the electrode capacitance is detected by measuring the
C X
C S
X
Serial resistor (R
is fully charged, part of the accumulated charge is transferred from
SAMPLING
Doc ID 15699 Rev 7
BURST
t
C
TRANSFER
S
(a few nF)
X
) is the acquisition rate.
) is the time required to charge C
) (1)
S
) refers to the charging of C
.
S
Figure
reaches the end of acquisition reference
S
6).
. The transfer cycle is repeated
STM8T ProxSense technology
C x (~20 pF)
Earth
C
T
S
(~5 pF)
X
to V
and the
X
) using a stable
TRIP
Ai15249a
.
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