Semtech SX865x系列4或5线电阻触摸屏控制方案

电子工程师 2019-04-01 617

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关键词： Semtech , SX865x系列 , 电阻触摸屏

Semtech公司的SX865x系列(SX8654, SX8655和SX8656)是4/5线电阻触摸屏控制器,低电压2.3V-3.6V工作,低功耗,关断电流仅0.4uA,器件集成了LDO稳压器,4/5线触摸屏接口,精密的比率12位ADC,高达5000(X-Y)座标/秒.主要用在游戏机,手提音乐设备,手机,DSC,DVR,POS/POI终端和触摸屏监视器.本文介绍了SX865x系列主要特性和方框图, 接近检测接口框图,以及模拟前端(AFE)框图, 触摸接口框图和应用框图,典型应用电路框图推荐外接元件数值表.

The SX8654, SX8655 and SX8656 belong to a family of high performance haptics enabled 4/5-wire resistive touch screen controller with proximity detection, optimized for hand held applications such as mobile phones, portable music players, game machines, point-of-sales terminal and other consumer and industrial applications. They feature a wide input supply range from 2.3V to 3.6V. The controller computes touch screen X-Y coordinates and touch pressure with a precision, low power 12-bit analog-digital converter. On-chip data averaging processing algorithms can be activated to reduce host activity and suppress system noise. The processing core features low power modes which intelligently minimize current in operation as well as in automatic shut-down.

A capacitive proximity detection circuit has been integrated into the SX8654 and SX8656 to enable host controlled power management for battery applications. Proximity detection above 5 cm is possible using either the resistive touch screen as the sensor or with a single conductive plate, with communication to the host via the serial interface.

The SX8654 and SX8655 also integrate a haptics motor driver for Linear Resonant Actuator (LRA) and Eccentric Rotating Mass (ERM) micro motors with up to 250mA drive current. Haptics control can be performed using either an external PWM signal or the I2C serial interface, providing simple host interfacing and minimizing its I/O requirement.

Integrated very high ESD protection, of up to ±15kV on display inputs not only saves cost and board area, but also increases application reliability.

The three devices have an ambient operating temperature range of -40°C to +85°C, and are offered in both a 4mm x 4mm, 20-lead QFN package and 2.07mm x 2.07mm 19-lead CSP package for spaceconscious applications.

SX865x系列主要特性:

Low Voltage Operation

2.3V to 3.6V Supply

Integrated Low Drop Out (LDO) Regulator

Low Power Consumption

30uA@2.3V 8ksps (ESR)

0.4uA Shut-Down Current

4/5-Wire Touchscreen Interface

   Precision, Ratiometric 12-bit ADC

Up to 5000 (X-Y) coordinates/second (c/s)

   Programmable Digital Filtering/Averaging

Touch Pressure Measurement (4-Wire)

   Programmable Operating Mode (Manual,Pen Detect, Pen Trigger)

Capacitive Proximity Sensing (SX8654/56)

No Additional Components Required

Uses Resistive Touchscreen or a Simple Conductive Area as the Sensor

>5 cm Detection Distance

8uA @ 200ms Scan Period

Fully Programmable (Sensitivity, etc)

Haptics Driver for LRA and ERM (SX8654/55)

Haptics Waveform Generation Control (I2C or PWM Input)

Short Circuit Protection

Early Warning and Over-Temperature Monitoring and Protection

400kHz I2C Serial Interface

Several Host Operating Modes Available

Maskable Interrupt Output (NIRQ)

Real-time Events Monitoring (AUX1-3)

   Polling (I2C)

Hardware, Software, and Power-On Reset

-40°C to +85°C Operating Temperature Range

15kV HBM & IEC ESD Protection

Small Footprint Packages

   Pb & Halogen Free, RoHS/WEEE compliant

SX865x系列应用:

Game Machines, Portable Music Players

Mobile Phones

DSC, DVR, Phones

   POS/POI Terminals

Touch-Screen Monitors