Supertex inc.
Dimmable, Low Noise, 16 channel
EL Lamp Driver
►
Sixteen channel EL lamp driver with single common
terminal
►
1nF maximum load on each of the sixteen channels
►
Independent dimming capability for all lamps
►
Sixteen brightness levels for each lamp
►
1.8 to 5.5V operating supply range
►
1.7V logic interface
►
Dedicated enable logic pin
►
340V
P-P
nominal output voltage for high brightness
►
Low audible noise
►
Output voltage regulation
►
EL1 - EL16 outputs fall time control
►
Two EL frequency controls
►
External switching MOSFET
►
I
2
C data communication control
►
Single lithium-ion cell compatible
►
One miniature inductor to power sixteen lamps
►
Independent lamp and converter frequency setting
►
Split supply capability
►
5x5mm, 32-Lead QFN package
HV881
Features
The HV881 has two internal oscillators and a high voltage
EL lamp driver. An external MOSFET is driven by the switch
oscillator to generate output voltage.
The frequency for the external switching MOSFET is set
by an external resistor connected between the RSW-Osc
pin and the VDD supply pin. The EL lamp driver frequency
can be set by either an external logic signal frequency at
the SEL pin or by an external resistor connected between
the REL-Osc pin and VDD pin. If external frequency is input
at the SEL pin, the REL-Osc pin should be connected to
ground.
An external inductor is connected between the LX and VDD
or VIN pins for split supply applications. Depending upon
the EL lamp sizes, a 1.0 to 10.0nF capacitor is connected
between the CS pin and ground. The C
S
capacitor is
connected to the internal H-bridge, and the energy stored
in the capacitor is therefore transferred to the EL lamp.
One side of all the sixteen EL lamps is connected to the
respective EL pins (EL1, EL2, etc.), and the other side is
connected to the COM pin.
The external switching MOSFET charges the inductor and
discharges it into the capacitor at CS. The voltage at CS
will start to increase. Once the voltage at CS reaches the
desired regulation limit, the external switching MOSFET is
turned off to conserve power.
The HV881 allows for controlling the fall time of the EL1
- EL16 outputs by an external resistor from the RSLOPE
pin to the VDD pin. This feature can be used to reduce
the audible noise of the EL lamp or to increase the lamp
brightness.
The brightness of each of the sixteen EL lamps can be
independently controlled to have one of fifteen brightness
levels or can be completely turned off by the serial data
(SDA) input. The serial data input has a 4-bit binary code
for each lamp, to control the brightness level from level 0
to level 15. The brightness is controlled by controlling the
number of EL frequency cycles (from 0 to 15) in a group of
15 cycles.
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►
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Applications
General Description
Multi-segment, variable displays
Cell phone keypads and displays
Multi-segment remote controls
Handheld wireless communication products
Global Positioning Systems (GPS)
The Supertex HV881 is a 16 channel EL lamp driver with a
single common terminal. It can drive up to a 1nF EL lamp load
(approx. 0.3in2 lamp size) on each of the sixteen channels.
The input supply voltage range is 1.8 to 5.5V. The logic
interface to the device can be as low as 1.7V. The device
has an enable logic input pin to turn the device on or off.
The device is designed to minimize audible noise emitted by
the EL lamp. The HV881 uses an external MOSFET, a single
inductor and minimum number of passive components to
drive all sixteen EL lamps. The device is designed such that
the input voltage to the inductor can be different from the
input voltage to the device (split supply).
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
HV881
Ordering Information
Device
HV881
5.00x5.00mm body
0.8mm height (max)
0.50mm pitch
Pin Configuration
32-Lead QFN
32
1
HV881K7-G
-G indicates package is RoHS compliant (‘Green’)
32-Lead QFN Package
Absolute Maximum Ratings
Parameter
V
DD
, supply voltage
EN, SDA, SCL, S
EL
V
CS
, output voltage
(top view)
Value
-0.5 to 7.0V
-0.5 to V
DD
+0.5V
-0.5 to 215V
0.48V
-65°C to +150°C
+125°C
Note:
Pads are at the bottom of the package. Center heat slug is at ground
potential.
Product Marking
Storage temperature
V
REG
, external input voltage
Maximum junction temperature
Absolute Maximum Ratings are those values beyond which damage to the
device may occur. Functional operation under these conditions is not implied.
Continuous operation of the device at the absolute rating level may affect
device reliability. All voltages are referenced to device ground.
L = Lot Number
HV881
YY = Year Sealed
LLLLLL
WW = Week Sealed
YYWW
A = Assembler ID
AAACCC
C = Country of Origin
= “Green” Packaging
32-Lead QFN Package
Package may or may not include the following marks: Si or
Thermal Resistance
Package
32-Lead QFN
θ
ja
25°C/W
(Mounted on 4-layer FR4 9-via PCB, 76mm x 114mm x 1.44mm)
Recommended Operating Conditions
Sym
V
DD
f
SW
f
EL
S
EL
C
LOAD
C
COM
T
j
Parameter
Supply voltage
Switching frequency
EL output frequency
Input for EL output frequency
Lamp capacitance per EL output
COM lamp capacitance
Operating temperature
Min
1.8
50
200
1600
0
0
-40
Typ
-
-
-
-
-
-
-
Max
5.5
200
1000
8000
1.0
16
+85
Units
V
kHz
Hz
Hz
nF
nF
°C
Conditions
---
---
---
S
EL
= 8 x (f
EL
) and 50% duty cycle
---
---
---
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
2
Tel: 408-222-8888
www.supertex.com
HV881
Electrical Characteristics
Sym
V
CS
V
LAMP
I
DDQ
I
DD
I
IN
V
REG
f
EL
f
SW
D
V
IH
V
IL
I
Logic
I
Logic-SEL
V
GATE
t
GATE-RISE
t
GATE-FALL
t
f
f
CLK
t
SU
t
H
Parameter
Output regulation voltage
Differential output voltage
Quiescent V
DD
supply current
Input current going into the V
DD
pin
Input current including inductor current
External input voltage range
EL Lamp frequency
Switching transistor frequency
External MOSFET duty cycle
SEL, EN, SDA, SCL logic pins input
high level
SEL, EN, SDA, SCL logic pins input
low level
EN, SDA, SCL pins input current
SEL logic pin input current
External MOSFET gate voltage
External MOSFET gate voltage rise
time
External MOSFET gate voltage fall
time
EL1 - EL16 outputs fall time for
½ EL cycle
SCL speed
Setup time before clock falls
Hold time after clock falls
(Over recommended operating conditions unless otherwise specified T
J
= 25°C)
Min
145
290
-
-
-
0
-
-
-
1.7
0
-1.0
-1.0
-
-
-
-
-
300
850
Typ
170
340
-
-
-
-
200
90
-
-
-
-
-
8.0
100
-
190
-
-
-
Max
195
390
1000
350
110
0.44
-
-
88
V
DD
0.2
1.0
12.0
-
-
20
-
500
-
-
Unit
V
V
nA
µA
mA
V
Hz
kHz
%
V
V
µA
µA
V
ns
ns
µs
kHz
ns
ns
Conditions
V
DD
= 1.8 to 5.5V
V
DD
= 1.8 to 5.5V
V
DD
= 5.5V
V
DD
= 5.5V, R
EL
= 2.0MΩ
R
SW
=1.0MΩ, R
SL
= 800kΩ
See Typical Application Circuit,
V
IN
= 4.2V
V
DD
= 1.8 to 5.5V
R
EL
=2.0MΩ
R
SW
=1.0MΩ
---
V
DD
= 1.8 to 5.5V
V
DD
= 1.8 to 5.5V
V
DD
= 1.8 to 5.5V
V
DD
= 1.8 to 5.5V
V
DD
= 1.8 to 5.5V
V
DD
= 1.8 to 5.5V, C
L
= 330pF
V
DD
= 1.8 to 5.5V, C
L
= 330pF
R
SL
= 800kΩ, V
DD
= 3.0V,
V
CS
=170V
---
---
---
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
3
Tel: 408-222-8888
www.supertex.com
HV881
Typical Output Waveform
V
CS
EL
1
COM
EL Lamp Brightness Control using I
2
C
No of
bits
-
1
bit
start
bit
7
bits
slave
addr
1
bit
W
bit
1
bit
Ack
8
bits
byte
0
1
bit
Ack
8
bits
byte
1
1
bit
Ack
8
bits
byte
2
1
bit
Ack
8
bits
byte
3
1
bit
Ack
8
bits
byte
4
1
bit
Ack
8
bits
byte
5
1
bit
Ack
8
bits
byte
6
1
bit
Ack
8
bits
byte
7
1
bit
Ack
1
bit
stop
bit
The I
2
C format for the SDA input is shown below:
7-bit slave address: 000 0110 (0x06 in hex)
Note:
The I
2
C is write-only. So the W bit has to always be logic low. (A “0” indicates a transmission write).
Each of the EL lamp’s brightness controls is a 4-bit binary number which is provided by the serial data input (SDA).
Byte 0 controls both the 16 level brightness of EL_lamp1 (bit0 - bit3) and EL_lamp2 (bit4 - bit7) and similarly, other bytes
control the brightness of other pairs of lamp.
1. If all the 4 bits for a designated EL lamp are L, the differential voltage across the lamp is zero.
2. If any of the 4 bits for a designated EL lamp is H:
a. The 4-bit value sets the average number of cycles for which the EL lamp voltage is non-zero.
b. The EL lamp brightness is linearly proportional to the binary lamp control code.
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
5
Tel: 408-222-8888
www.supertex.com
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