SUPERTEX HV858

Supertex inc.
HV858
Tri-EL Lamp Driver IC
General Description
Features
Tri-EL lamp driver with common terminal
Independent brightness control for all 3 lamps
1.8V to 6.5V Operating Supply Voltage
Output voltage regulation
Two-pin serial data communication for control
Linear brightness control with seven steps at constant
efficiency
128kHz Fixed Switching Frequency
Split supply capability
Patented high efficiency EL lamp driver
Single miniature inductor drives all 3 lamps
Only 4 external components
Burst mode power converter for best efficiency
CMOS compatible serial interface with noise rejection
150nA max. leakage current when disabled
Power-on reset causes all outputs to be off when first
powered up
Small 10-pin MSOP package
10-pin DFN/MLP package (0.8mm thickness)
Applications
The Supertex HV858 is a high voltage triple EL lamp driver
designed for driving combined EL lamps of up to 3.0 in2
(1.0 in2 each). The input supply voltage range is from 1.8V
to 6.5V. The device is designed such that the input voltage
to the inductor can be different from the input voltage to the
device (split supply). The device uses a single inductor and
a minimum number of passive components. The nominal
regulated output voltage that is applied to the EL lamp is
±95V. The HV858 has two internal oscillators, one for the
internal switching MOSFET, and the other for the high voltage
EL lamp driver. The EL lamp frequency is fixed internally at
500Hz. The power converter oscillator runs 256 times faster
than the EL lamp driver at 128kHz.
An external inductor is connected between the LX and VDD
pins (or between the LX pin and separate voltage source in
the case of a split supply application). A 0.002-0.01µF, 100V
capacitor is connected between the Cs pin and ground.
The switching MOSFET charges the external inductor and
discharges it into the capacitor at the Cs pin. The voltage at
Cs will start to increase. Once the voltage at Cs reaches a
nominal value of 95V, the switching MOSFET is turned OFF
to conserve power.
One side of the 3 EL lamps is connected to the Com pin of
HV858 and the other side to the EL1, EL2, and EL3 pins of the
HV858. Each EL lamp output may be independently controlled
to have one of the 7 brightness levels or can be completely
turned OFF by a 10-bit serial data input register. The 10-bit
control code has 3 bits to control the brightness level of each
EL Lamp and one bit to optionally control the power converter.
The 3-bit binary brightness control code controls the number
of 500Hz cycles (from 0 to 7) in a group of 7 cycles.
Mulit-segment, variable displays
Cell phone keypads and displays
MP3 players
Watches
Typical Application Circuit
LX
VIN
D
+
CIN
-
+
VDD
CS
1 LX
CDD
-
Serial Data in
CS 10
2 GND
Com 9
3 VDD
EL3 8
EL Lamp 3
4 SDI
EL2 7
EL Lamp 2
5 SCK
EL1 6
EL Lamp 1
HV858
Clock
A011706
Supertex inc.
A011706
· 1235 Bordeaux Drive, Sunnyvale, CA 94089
· Tel: (408) 222-8888 · FAX: (408) 222-4895 · www.supertex.com
1
HV858
Ordering Information
Device
Package Options
DFN/MLP-10
MSOP-10
HV858
HV858K7-G
HV858MG
HV858MG-G
-G indicates the package is RoHS compliant - “Green”
Absolute Maximum Ratings
Pin Configuration
Lx
GND
VDD
SDI
SCK
VDD
-0.5 to +7V
CS
SDI, SCK
-0.5 to +7V
ISW
0.7A peak
0.5 to +110V
HV858MG
HV858K7
1
10
2
9
3
8
4
7
5
6
CS
COM
EL3
EL2
EL1
Lx
1
GND
VDD
2
9
COM
3
8
EL3
SDI
4
7
EL2
VCS
SCK
5
6
EL1
Power dissipation
DFN/MLP-10
(top view)
10
MSOP-10
(top view)
Storage temperature
Operating temperature
250mW
-65ºC to +150ºC
-40ºC to +85ºC
Recommended Operating Conditions
Symbol
VDD
ISW(pk)
TA
Parameter
Min
Supply voltage
1.8
Peak switch current
Operating temperature
Specifications (unless otherwise specified:
Symbol
Typ
Parameter
-40
Max
Unit
6.5
V
0.4
A
85
ºC
Conditions
TA = 25ºC, VDD = 2.6V to 5.5V)
Min
Typ.
Max
Unit
Conditions
4
6
Ω
VDD = 1.8 to 6.5V, ISW = 100mA
RSW
ON resistance of switching transistor
VCS
Output voltage
85
95
105
V
S1...S9 = 0, VDD = 1.8 to 6.5V, no load
Differential lamp voltage
170
190
210
V
VCOM to any EL, no load, code1 = 111
IDD
VDD supply current
0.01
0.15
0.25
mA
VCS = 20V, no load, PWR_ON = 1
ICS
VCS supply current
10
50
100
µΑ
VCS = 75V, no load
100
150
nA
S1...S9 = 0, SCK and SDI can be tied to VDD
or GROUND
108.8
128
147.2
kHz
See Figure 1
VLAMP
IDDQ
VDD leakage current when disabled
fSW
Inductor switching frequency
fEL
Lamp frequency
425
500
575
Hz
VLOW
Logic pin input Low level
-0.5
0
0.2 VDD
V
VHIGH
Logic pin input High level
0.8 VDD
VDD
VDD +
0.5
V
ILOGIC
Logic pin input current
-0.1
0
0.1
µΑ
0 < VDD< 7V
70
mA
See Figure 1.
VDD = VIN = 3V, total lamp size = 3.0in2
(1.0in2 each), 10-bit SDI serial code = 1111111111
IDD
Inductor current
56
VCS
Output voltage
82.5
V
fEL
Lamp frequency
500
Hz
DMAX
Maximum PWM switch duty cycle
80
88
94
%
fCLK
SCK speed
1
MHz
TSU
SDI setup time before SCK rises
30
ns
TH
SDI hold time before SCK rises
30
ns
Note 1: Code refers to the 3-bit Brightness Control Code for the respective EL Lamp
2
For all codes except code1 = 000
VCS = 20V, RLOAD = 20Ω
A011706
HV858
Pin Configuration
Pin
Name Description
1
LX
Inductor pin
2
GND
Ground pin
3
VDD
Input voltage supply pin. It is common practice to use a bypass
capacitor as close as possible to the device on this pin.
4
SDI
Serial data input pin
5
SCK
Serial clock input pin
6
EL1
EL lamp 1 pin
7
EL2
EL lamp 2 pin
8
EL3
EL lamp 3 pin
9
COM
Common pin for one side of all 3 EL lamps
10
CS
High Voltage capacitor pin
Logic Input Conditions
EL Lamp Brightness Control
The serial data input consists of a 10-bit string, 3-bits of brightness control and one bit(10th bit) to optionally control the power
converter. The power converter runs if any of the EL lamps has a
non-zero brightness value or if the PWR_ON bit is high while the
other 9 bits are low.
The EL Lamp brightness control is a 3-bit binary number stored
in a latch, which is provided by a serial to parallel conversion shift
register.
1.
SDI may be H or L if SCK is H.
2.
SCK may be H or L if SDI is H.
3.
While inputting serial data to the shift register, SDI can
change value only when SCK is L.
1.
If all the 3 bits for a designated EL lamp are L, the differential
voltage across that lamp will be zero.
2.
If any of the 3 bits for a designated EL lamp is H:
a.
4.
b.
The 3-bit value sets the average number of cycles
for which the EL lamp voltage is non-zero.
The EL lamp brightness is linearly proportional
to the binary lamp control code.
The previous 10 bits of serial input will be latched when
SDI makes L to H transition while SCK is H.
Logic Input Diagram
S1
S2
S3
S4
LSB of
EL1
MSB of
EL2
S5
S6
S7
LSB of
EL2
MSB of
EL3
S8
S9
S10
LSB of
EL3
PWR_ON
SDI
MSB of
EL1
EL 1 Control
EL 2 Control
EL 3 Control
SCK
Note:
1. Serial data is latched when SDI makes L to H transition and while SCK is H.
2. S1 is the first serial data input being fed.
Latches
in Data
A011706
3
HV858
Logic Truth Table
L = Low (L = 0 to L < 20% of VDD)
H = High (80% of VDD < H = VDD)
NA = Does not control brightness of the designated EL lamp
Brightness
Level
Device
disabled
Device
enabled
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
7/7
H
H
H
NA
NA
NA
NA
NA
NA
NA
6/7
H
H
L
NA
NA
NA
NA
NA
NA
NA
5/7
H
L
H
NA
NA
NA
NA
NA
NA
NA
4/7
H
L
L
NA
NA
NA
NA
NA
NA
NA
3/7
L
H
H
NA
NA
NA
NA
NA
NA
NA
2/7
L
H
L
NA
NA
NA
NA
NA
NA
NA
1/7
L
L
H
NA
NA
NA
NA
NA
NA
NA
Off
L
L
L
NA
NA
NA
NA
NA
NA
NA
7/7
NA
NA
NA
H
H
H
NA
NA
NA
NA
6/7
NA
NA
NA
H
H
L
NA
NA
NA
NA
5/7
NA
NA
NA
H
L
H
NA
NA
NA
NA
4/7
NA
NA
NA
H
L
L
NA
NA
NA
NA
3/7
NA
NA
NA
L
H
H
NA
NA
NA
NA
2/7
NA
NA
NA
L
H
L
NA
NA
NA
NA
1/7
NA
NA
NA
L
L
H
NA
NA
NA
NA
Off
NA
NA
NA
L
L
L
NA
NA
NA
NA
7/7
NA
NA
NA
NA
NA
NA
H
H
H
NA
6/7
NA
NA
NA
NA
NA
NA
H
H
L
NA
5/7
NA
NA
NA
NA
NA
NA
H
L
H
NA
4/7
NA
NA
NA
NA
NA
NA
H
L
L
NA
3/7
NA
NA
NA
NA
NA
NA
L
H
H
NA
2/7
NA
NA
NA
NA
NA
NA
L
H
L
NA
1/7
NA
NA
NA
NA
NA
NA
L
L
H
NA
Off
NA
NA
NA
NA
NA
NA
L
L
L
NA
All lamps
Off
EL1
EL2
EL3
A011706
4
HV858
Functional Block Diagram
Lx
VIN
+
CIN
1N914
VDD
Cs
LX
Cs
Enable
EL1
Switch Osc
VSENSE
+
Disable
Vcs
-
GND
EL2
VREF
SDI
SCK
Logic Control
EL1
EL2
EL3
COM
Output
Drivers
Vcs
EL3
Vcs
COM
Note: This drawing is a generalized representation. Actual internal circuitry may differ.
Differential Output Waveform
The following is the differential output waveform across the lamp for each 3-bit input code for each lamp.
Code 000
500Hz
Code 001
Code 010
Code 011
Code 100
Code 101
Code 110
Code 111
Group of 7 Cycles
.....Pattern Repeats....
A011706
5
HV858
Figure 1 : Test Circuit
LX = 68µH **
VIN
+
CS = 3.3nF, 100V
CIN = 4.7µF
-
VDD
D = IN914*
1 LX
+
CDD =
0.1µF
-
CS 10
2 GND
Com 9
3 VDD
EL3 8
EL Lamp 3
4 SDI
EL2 7
EL Lamp 2
5 SCK
EL1 6
EL Lamp 1
(1.0 in2)
(1.0 in2)
(1.0 in2)
HV858
Stream of
Serial Data
(1's and 0's)
*Any 100V fast reverse recovery diode can be used
Note: Maximum lamp size for each segment is 1.0 in2. To drive larger size lamps, any combination of EL1, EL2 and EL3 can be paralleled. However,
the 3-bit serial data input code (for each output) should be such that the paralleled outputs have the same code.
Typical Performance (V
DD
= VIN = 3.0V)
EL1 Brightness
st
1 9-bit SDI code
000111111
001111111
010111111
011111111
100111111
101111111
110111111
111111111
Level
0/7
1/7
2/7
3/7
4/7
5/7
6/7
7/7
ft-lm
0
1.60
3.24
4.95
6.68
8.44
10.21
12.05
IDD (mA)
VCS
(V)
42.6
44.7
46.9
48.9
51.2
53.3
55.0
56.2
85.7
85.3
84.9
84.5
84.0
83.5
82.9
82.5
2
Cd/m
0
5.46
11.08
16.94
22.85
28.85
34.93
41.2
A011706
6
HV858
10-Lead DFN/MLP Package Outline (K7)
0.087
(2.200) 0.020
(0.500)
0.118
(3.000)
0.059
(1.500)
0.118
(3.000)
0.063
(1.600)
Pin #1 Index
0.059
(1.500)
+0.006
-0.004
+0.150
0.300
-0.100
0.012
Pin #1 Index
)
+0.001
-0.001
+0.030
0.020
-0.020
)
Bottom View
0.0295±0.002
(0.75±0.05)
Side View
)
+0.002
-0.003
+0.050
0.250
-0.070
0.010
)
Top View
0.001
)
0.008
(0.200)
Dimensions in Inches
(Dimensions in Millimeters)
2. MLP Package dimensions conform to JEDEC MO-229
1. Measurement Legend =
)
10-Lead MSOP Package Outline (MG)
0.020±0.006
(0.500±0.152)
GATE PLANE =
0.010
(0.250)
0.193±0.004
(4.900±0.100)
0.118±0.004
(3.000±0.100)
0°– 6°
0.021±0.005
(0.550±0.150)
Full Circle
or Half Circle
DETAIL A
0.118±0.004
(3.000±0.100)
0.033±0.004
(0.850±0.100)
0.037±0.005
(0.950±.015)
0.013±0.003
(0.325±0.075)
0.007±0.002
(0.180±0.050)
SEE DETAIL A
0.004±0.002
(0.100±0.050)
Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell its products for use in such applications, unless it receives an adequate
"product liability indemnification insurance agreement". Supertex 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 or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest
product specifications, refer to the Supertex website: http//www.supertex.com.
©2006 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited.
Doc. # DSFP-HV858
A1011706
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 222-8888 / FAX: (408) 222-4895
A011706
7
www.supertex.com