/a>LED” title=”LED”>LED” title=”LED”>LED driver or GPIO, with automatic ambient drift correction for each sensing terminal, I2C serial interface, 10 with S/H circuit SAR ADC with integrated voltage regulator. Mainly used in mobile phones” title=”mobile phones”>mobile phones, PCs and household appliances” title=”household appliances”>household appliances. This article introduces the main features of AK4160, block diagram, 16-channel Touch switch connection diagram and 8-way touch switch and 8-way LED Display connection diagram, evaluation board AKD4160-A function, block diagram, circuit diagram and component layout.
The AK4160 is a low operating voltage and low power consumption 16-channel capacitive touch sensor.
Maximum 8 channels out of the 16-channel can be configured to LED drive or GPIO. The AK4160 has a channel independent automatic correct function of environmental drifts for each sense input. It reduces false detection by continuous calibration of the internal reference value in the situation when the input capacitance of the touch switch is changed by the external factors such as hydrothermal conditions. The automatic initial setting function sets the charge current and charge time according to the size and the shape of a touch switch. The AK4160 can be configured via serial interfaces, it is suitable for mobile phones, PCs and home electric applications.
AK4160 main features:
Up to 16 capacitive sensor inputs
Up to 8 general purpose inputs/outputs with PWM control for LED
Automatic initial setting function for the charge current and time
Independent automatic environmental drifts correct function for each sense terminal
Independent threshold configuration for each sense terminal
Selectable multi touch feature
Integrated Median Averaging Filter
Selectable 3 interrupt outputs that be able to use as GPIOs
Reset Input pin
I2C Serial Interface
10 bit SAR A/D Converter with S/H circuit
Low Power Consumption: Typ. 3.4uA (Sampling rate=512ms, 16ch Sensor input Active)
Power Down Current: Typ. 1.0uA
Low Power Operation: VDD = 1.71V ~ 3.6V
Operating Temperature: Ta = -40 ~ 85℃
Package: 28pin QFN (4.0mm x 4.0mm, pitch 0.4mm)
Figure 1. AK4160 block diagram
The touch switch (capacitor) that is connected to the sense input is charged up with direct current during a given period of time. The switch is connected to ground before the measurement. As a result, the touch switch capacitance is completely discharged before start being charged. When the touch switch is fully charged, the voltage is inversely proportional to the capacitance. When the touch switch is touched, this charge voltage decreases because the capacitance value when the switch is touched is larger than when not touched. The charged voltage is converted to a digital data by ADC. The data is get through the noise reduction filter, and compared to a touch threshold value. When the measurement value exceeds the threshold that is corrected environmental drifts, the AK4160 updates the status register to the touch detected state .
Figure 2. AK4160 touch sensor block diagram
Figure 3. AK4160 16-way touch switch connection diagram
Figure 4. AK4160 8-way touch switch and 8-way LED Display connection diagram
Evaluation Board AKD4160-A
The AKD4160-A is an evaluation board for the AK4160, which is 16-channel capacitive touch sensor with a low operating voltage and a low operating power. Since the AKD4160-A has a I2C serial I/F, it is possible to control the AK4160 by writing and reading registers, and operate kinds of touch pad with a capacitor sensor connector on the AKD4160-A.
Evaluation Board AKD4160-A Features:
• I2C serial I/F
• Cap Sensor Connector
• Touch Pad Operations
Figure 5. Block Diagram of Evaluation Board AKD4160-A
Figure 6. Evaluation Board AKD4160-A Circuit Diagram (1)
Figure 7. Evaluation Board AKD4160-A Circuit Diagram (2)
Figure 8. Evaluation Board AKD4160-A Circuit Diagram (3)
Figure 9. Evaluation Board AKD4160-A Component Layout
For details, see: