DRV8662: Tablet PC Monolithic Piezo Touch Screen Driver Solution

TI’s DRV8662″ title=”DRV8662″>DRV8662 is a monolithic piezoelectric touch driver that integrates a 105V boost switch, a power diode and a fully differential amplifier.” title=”piezo touch”>piezo touch driver. This versatile device can drive both high and low voltage piezoelectric touch actuators. The input signal can be differential or single-ended. The DRV8662 supports four GPIO-controlled gains: 28.8dB, 34.8dB, 38.4dB, and 40.7dB.

The boost voltage is set with two external resistors, and the boost current is limited by the REXT resistor. Since the architecture of the boost converter does not allow the meta-current to exceed the limit set by the REXT resistor, the DRV8662 is ideal for portable applications.

DRV8662: Tablet PC Monolithic Piezo Touch Screen Driver Solution
Figure 1 DRV8662 block diagram
DRV8662: Tablet PC Monolithic Piezo Touch Screen Driver Solution
Figure 2 DRV8662EVM evaluation module outline drawing

DRV8662 main features

• High Voltage Piezo Touch Driver

• Drive up to 100nF at 200Vpp and 300Hz

• Drive up to 300nF at 100Vpp and 300Hz

• Drive up to 680nF at 50Vpp and 300Hz

• Differential output

• Integrated boost converter

• Adjustable boost voltage

• Adjustable current limit

• Integrated power FETs and diodes

• No transformer required

• 1.5ms fast startup time

• Wide input voltage range of 3.0V~5.5V

• 1.8V compatible digital pins

•Thermal Protection

• Adopt 4mm×4mm×0.9mm QFN package (RGP)

DRV8662 application

•cell phone

• Portable game console

• Portable Navigation Device

• Tablet devices

Figure 3 Tablet PC” title=”Tablet PC” > Tablet PC and e-book system block diagram

DRV8662EVM Evaluation Module

The DRV8662EVM evaluation module is a full-scale, high-voltage piezoelectric driver with fast response time for single-layer and multi-layer piezoelectric actuators. Using an adjustable 100V integrated boost converter, the DRV8662 can differentially drive loads up to 200V. The complete evaluation module includes the DRV8662RGP piezoelectric touch driver, programmable MSP430 and passive components.

DRV8662EVM Evaluation Module Main Features

• High Voltage Touch Driver

• Drive single and multilayer piezoelectric actuators

• Adjustable 200V differential output

• Programmable sample waveform and I2C input to be used

MSP430

• External PWM and analog inputs

• Wide input voltage range from 3.0V to 5.5V

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