Industry’s Most Highly Integrated
Piezo Haptic Driver
Eric Siegel
Product Marketing Engineer, Touch Screen Controllers and Haptics
THIS INFORMATION EMBARGOED
UNTIL JULY 20
What is Haptics?
• Touch screens are replacing traditional user interfaces
Cell Phones & Handhelds
Tablets
Laptops & Desktops
Portable Gaming Devices
• Touch screens have one major disadvantage
– No physical or mechanical feedback when
the screen is pressed or an event occurs
– Loss of tactile or haptic feedback
• The solution is haptics….
– Haptics refers to the sense of touch and is a
technology that provides mechanical feedback
through the use of vibrations to simulate
specific events or effects.
• Benefits of Haptics
– Improves task performance
– Increases user satisfaction
– Provides a more realistic experience
Touch ecosystem
Touch Panel and
Display
Touch Location
Applications Processor/
Chipset reference design
Haptics effects
Haptics
SW
Touch
Screen
TSC
Controller
Haptics
Haptics
Driver
Driver
Haptics
SW
Haptics actuators
Note: Haptics
Software stored
in only one of
two locations
THIS INFORMATION EMBARGOED UNTIL JULY 20
Piezo actuator-based haptics
• Enables high-definition and localized Haptics effect generation
• Piezo actuators are very thin (<1mm)
• Piezo actuators are either single-layer or multi-layer
– Single Layer
• Need up to 200 Vp-p to drive
• More cost effective
• Have low capacitance and can be driven with lower current
– Multi-layer
• Need up to 50Vp-p to drive multi-layer piezos
• Cost scales linearly with the number of piezo layers
• Have high capacitance and needs higher current drive
Introducing the DRV8662
Industry’s most integrated single-chip piezo haptic
driver
• High analog integration (boost converter, diode)
– 50% smaller solution size than leading competition
• Does not need an external transformer
– 40% lower system solution cost than leading
competition
• Analog input
– Can be driven by DAC or filtered pulse width
modulation (PWM)
• GPIO gain control
– Supports wide range of piezo actuator voltages
• 50-200 - volt peak to peak (Vpp) differential outputs
– Drive high-definition inaudible haptics effects
• Haptics frequencies up to 500-Hz
– Enables wide variety of high-resolution haptics effects
THIS INFORMATION EMBARGOED UNTIL JULY 20
Feel the difference
• Localized responses on the
screen
• Get haptic feedback from the
smallest actions onscreen
• Pluck a string on your guitar app
and feel the frequency associated
with that string, in the exact spot
you’re touching
• Feel each time your “bird missile”
ruffles its feathers or slams into the
wooden blocks
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Applications
Actuator response
Response and accuracy of haptics effects
Inertial
Piezo
• Low bandwidth
• High bandwidth
• Start-up and response times are slower
• Fastest response time and largest
bandwidth
• Lower bandwidth limits types of effects
• Motor (ERM) or linear actuator (LRA)
• DRV8601
• Wider range of effects
• Piezo bender or piezo module
• DRV8662
THIS INFORMATION EMBARGOED UNTIL JULY 20
Bandwidth profiles
Strength
Piezo actuators offer higher bandwidth than inertial actuators
ERM
spinning
ERM/
LRA
pulsing
Piezo pulsing
50Hz
LRA
Piezo
direct
drivedirect drive
175Hz
Frequency
300Hz
Response time of the DRV8662
Inertial Actuators vs. Piezo Actuators
Faster
response time
Piezo (DRV8662)
Strength
ERM, LRA
~30-60ms
<1ms
Time
THIS INFORMATION EMBARGOED UNTIL JULY 20
Competition vs. DRV8662
TI DRV8662
Integrated, high-voltage process solution
Competition’s flyback solution
BATTERY
VOLTAGE
C2
VBAT
C1
SW
1:N
EN
Baseband
IN+
Flyback
Solution
IN-
R1
FB
GATE
Haptic
Piezo
SOURCE
GND
R2
R3
• Low voltage process
• High voltage process
• Transformer – bulky, expensive
• Transformer-less
• External FET
• Integrated FET
• External eiode
• Integrated diode
• Difficult charge/discharge control schemes
that are separated
• Simple Op-Amp voltage controlled feedback
allowing adjustable gain
• Total board space ~200mm2
• Total Board Space ~100mm2
DRV8662 evaluation kit
Touch panel glass with Piezo
Actuator assembly
MSP430G2253
DRV8662
Complete Haptics Evaluation
• I2C Interface through MSP430
• Analog / PWM input option to the DRV8662 with I2C bypass
• Programmable MSP430 with sample code
THIS INFORMATION EMBARGOED UNTIL JULY 26
Summary
Small solution size
50% smaller with no
external transformer
Low solution cost
40% lower cost with no
expensive external transformer
50 to 200-Vpp
differential drive
Flexible architecture
High-definition haptics
effects
Can drive single or multi-layer
piezo actuators
For your readers
• DRV8662 Product Folder
– www.ti.com/drv8662-pr
• “What is haptics?” video
– www.ti.com/drv8662video-pr
• Technical support for
touch products
– www.ti.com/touchforum-pr
Thank You