Supertex inc.
HV892DB1
Inductorless,
Liquid Lens Driver Demoboard
General Description
The HV892DB1 liquid lens driver demoboard is controlled via
an I2C interface, is capable of driving capacitive loads of up to
200pF, and is compatible with 40VRMS to 60VRMS lenses.
Specifications
Parameter
Value
Supply voltage (VIN):
2.65 – 5.50V
20mA max operating
500nA max standby
A charge pump boost converter integrated on-chip provides
the high voltage necessary for driving the lens. No external
inductors or diodes are needed. The board requires only two
ceramic chip capacitors to complete a lens driver circuit.
Supply current (IIN):
An H-bridge output stage provides AC drive to the lens,
allowing the use of a single high voltage boost converter while
providing alternating polarity to the lens. Controlled rising and
falling edges on the drive waveform reduces EMI.
Load (lens) capacitance:
100 – 200pF
I2C reference voltage (VDD):
1.70 – 2.95V
I2C clock:
400kHz max
Output voltage (OUT1 – OUT2):
9.8 – 62.6VRMS,
adjustable via I2C
I2C address (7-bit):
0100011b
Board dimensions:
35.6mm x 26.2mm
Board Layout and Connections
VIN =
2.65 - 5.5V
VDD =
1.70 - 2.95V
I2C Bus
{
SCL
SDA
Connections:
VIN
Supply voltage to the HV892. Externally supplied VIN should
be between 2.65 and 5.50V.
GND
Circuit common.
VDD
Externally supplied logic reference voltage for the I2C interface. VDD should be between 1.70 and 2.95V.
SCL
I2C clock. Clock frequency should be no greater than
400kHz.
Doc.# DSDB-HV892DB1
B032114
CIN
CHV
Liquid Lens
100 - 200pF
IC1
SDA
I2C data.
OUT1 and OUT2
The lens driver output. Connect the lens between these two
terminals. Load (lens) capacitance should be between 100
and 200pF, including any stray capacitance.
Note:
The resistors shown in the connection diagram are the
normal I2C pull-ups. No additional pull-ups are required.
Supertex inc.
www.supertex.com
HV892DB1
HV892DB1 Circuit Schematic
I2C Bus
VDD =
1.70 -2.95V
VDD
SDA
SCL
VDD
SDA
SCL
VIN
VIN =
2.65 -5.50V
HV892
OUT2
VIN
CIN
2.2µF
OUT1
HV
OUT1
OUT2
Liquid Lens
100 - 200pF
GND1 GND2
CHV
4.7nF
GND
Bill of Materials
Part
Description
Value
Tolerance
Rating
Package
Manufacturer
Part Number
CIN
Ceramic capacitor
2.2μF
20%
6.3V
0603
Any
---
CHV
Ceramic capacitor
4.7nF
10%
100V
0603
Any
---
IC1
Lens driver
-
-
-
4x4 DFN
Supertex
HV892K7-G
Operation
Externally supplied VIN should be ramped up in less than
2.0ms to ensure the driver starts-up in standby mode. If
brought up slower, the driver may not start-up in standby
mode, with output amplitude at an indeterminate level. In
this case, writing AMP = 00h brings the driver to standby
mode. No damage will occur if VIN is brought up slower than
2.0ms.
A single byte (AMP) written to the HV892 controls the operation of the driver. Setting AMP = 00h causes the HV892 to
go into low power standby mode. Setting AMP = 01h to FFh
controls output amplitude in 255 monotonic steps.
VOUT(RMS) = 9.6VRMS + AMP • 208mVRMS
The HV892 is write-only. No readback of the AMP byte is
possible.
Light capacitive loads may result in waveform distortion.
This is due to the output pins being held at a high-Z state for
a portion of the waveform. Without adequate capacitance
to hold up the voltage, some droop may be observed when
DC-loaded by oscilloscope probes.
The HV892’s 7-bit address is 0100011b. For large quantity
orders, other 7-bit addresses may be obtained.
The resistors shown on the above schematic are the I2C bus’
normal pull-ups. No additional pull-ups are required. Externally supplied VDD is the I2C bus’ reference voltage.
To avoid loading down the outputs, use instruments having at least 10MΩ input impedance when taking measurements. While many voltmeters may have a very high input
resistance on the DC scale, they frequently have only 1.0MΩ
input impedance on the AC scale. Also, be sure to use a
voltmeter with true RMS capability.
Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives
an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liability
to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and
specifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com)
Supertex inc.
©2014 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited.
Doc.# DSDB-HV892DB1
B032114
2
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com