sx8661 Semtech Corporation, sx8661 Datasheet - Page 83

• Manufacturer Part Number: sx8661
• Description: Low Power, Capacitive Button Touch And Proximity Controller 8 Sensors With Led Drivers And Analog Output
• Manufacturer: Semtech Corporation

1. No finger
=> No proximity detected
=> All LEDs OFF
ADVANCED COMMUNICATIONS & SENSING
7.3 Example of Touch+Proximity Module
7.3.1
To demonstrate the proximity sensing feature of the SX8661/SX863x family, a module has been designed and is
illustrated in figure below.
The touch button controller is running in stand-alone (i.e. without host) and uses the Autolight mode to turn LEDs
ON/OFF accordingly to the touch buttons and proximity sensing status.
7.3.2
Module operation can be seen as 5 steps which are described in figure below
Notes:
- For better user experience, bicolor LEDs have been used here but one could decide to design a module with
normal unicolor LEDs. In this case, step 3 above would simply consist in a higher (blue) intensity for the LED of
the button touched.
- For obvious demonstration purposes the overlay used here is transparent but in typical applications (TV,
Monitor, Set-top box, etc) the overlay would be opaque enough so that when LEDs are OFF (i.e. no proximity
detected) the PCB is not visible to the user.
Revision v3.2, January 2011
Overview
Operation
2. Finger approaches
=> Proximity detected
=> Blue LEDs turned ON
Figure 66
Figure 65
Low Power, Capacitive Button Touch and Proximity Controller
Touch+Proximity Module Operation
Touch+Proximity Module Overview
© 2011 Semtech Corp.
3. Button touch
=> Orange LED turned ON
(blue+orange = pink)
83
(8 sensors) with LED Drivers and Analog Output
4. Button release
=> Orange LED turned
OFF
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5. Finger removed
=> No proximity detected
=> Blue LEDs turned OFF
DATASHEET
SX8661