HV892
Inductorless Liquid Lens Driver
Features
►
Drives capacitive loads up to 200pF
►
Programmable drive amplitude (compatible with
40V
RMS
to 60V
RMS
lenses)
►
On-chip boost converter
►
No external inductor
►
I
2
C interface
►
Low operating current (≤20mA)
►
Low standby current (≤1.0µA)
►
Controlled drive edge reduces EMI
►
10-Lead 4x4mm DFN Package
General Description
The HV892 liquid lens driver is controlled via an I
2
C interface, is
capable of driving capacitive loads of up to 200pF, and is compatible
with 40V
RMS
to 60V
RMS
lenses.
A single byte (AMP) written to the HV892 controls the operation of
the driver. Setting AMP = 01h to FFh controls output amplitude in
255 monotonic steps. Setting AMP = 00h causes the HV892 to go
into low power standby mode, consuming less than 1.0µA. When
active, the HV892 draws less than 20mA.
A charge pump boost converter integrated on-chip provides the
high voltage necessary for driving the lens. No external inductors
or diodes are needed. Two ceramic chip capacitors are the only
external components required for a complete lens driver circuit.
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.
The HV892 is offered in a 10-Lead 4x4mm DFN package.
Applications
►
►
►
►
Cell phone cameras
PDA and ultracompact cameras
Bar code readers
Web and laptop cameras
Typical Application Circuit
I
2
C bus
V
IN
2.65 - 5.5V
C
IN
2.2μF 6.3V
SDA
SCL
V
DD
1.7 - 2.95V
VD
D
VIN
HV
C
HV
4.7nF 100V
HV892
GND1
GND2
OUT1
OUT2
Liquid Lens
100 - 200pF
SIRECTIFIER [ SIRECTIFIER SEMICONDUCTORS ]
