Resistive touch screen control scheme designed by AK4186

This article introduces the main features of AK4186, block diagram, 4-wire and 5-wire typical connection diagrams, touch screen input circuit and AKD4186-A evaluation board circuit diagram.

AK4186 is a 4-wire/5-wire resistive touch screen controller using 12-bit SAR ADC, with automatic continuous measurement and measurement data calculation functions and continuous readout functions, I2C serial interface, sampling rate 22.2kHz, working voltage 1.6V-3.6V, power consumption of 1.8V is 60uA, and has automatic shutdown function. It is mainly used in mobile phones, digital cameras, DVCs, smart phones and other portable devices.

AK4186 Main Features:

4-wire or 5-wire Touch Screen Interface

I2C Serial Interface

12bit SAR A/D Converter with S/H circuit

Sampling Rate: 22.2kHz

Pen Pressure Measurement (4-wire)

Continuous Read Function

Integrated Internal Osc (Sequence Mode)

Integrated Median Averaging Filter

Low Voltage Operation: VDD = 1.6V ~ 3.6V

PENIRQN Buffer Output

Low Power Consumption: 60μA at 1.8V

Auto Power Down

Package: 12pin CSP (1.7mm x 1.3mm, pitch 0.4mm)16pin QFN (3mm x 3mm, pitch 0.5mm)

Figure 1. AK4186 Block Diagram

Figure 2. AK4186 Typical Connection Diagram (4-wire, AK4186ECB)

Figure 3. AK4186 Typical Connection Diagram (4-wire, AK4186EN)

Figure 4. AK4186 typical connection block diagram (5-wire, AK4186ECB)

Figure 5. AK4186 typical connection block diagram (5-wire, AK4186EN)

AKD4186-A evaluation board

AKD4186-A is the board for evaluation of the touch screen controller AK4186, which adopted the CSP small package suitable for the cellular phone, the handheld game machine. Since AKD4186-A has a touch-screen I/F and a digital I/O power supply input terminal, it is easily connectable with a target system of low power/voltage drive. Furthermore, since the analog input terminal is equipped analog voltage can also be measured.

Figure 6. Touch screen input circuit

Figure 7. AKD4186-A evaluation board circuit diagram