HV825
High Voltage EL Lamp Driver IC
Features
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Processed with HVCMOS
®
technology
1.0V to 1.6V operating supply voltage
DC to AC conversion
Output load of typically up to 6nF
Adjustable output lamp frequency
Adjustable converter frequency
Enable function
General Description
The Supertex HV825 is a high voltage driver designed for driving
EL lamps typically up to 6nF. The input supply voltage range
is from 1.0V to 1.6V. The device uses a single inductor and a
minimum number of passive components. The typical output
voltage that can be applied to the EL lamp is ±56V.
The HV825 can be enabled/disabled by connecting the R
SW-Osc
resistor to V
DD
/GND.
The HV825 has two internal oscillators, a switching bipolar
junction transistor (BJT), and a high voltage EL lamp driver.
The frequency for the switching BJT is set by an external
resistor connected between the RSW-Osc pin and the VDD
supply pin. The EL lamp driver frequency is set by an external
resistor connected between REL-Osc pin and the VDD pin. An
external inductor is connected between the LX and VDD pins.
A 0.01 to 0.1µF, 100V capacitor is connected between the CS
pin and the GND pin. The EL lamp is connected between the
VA pin and the VB pin.
The switching BJT charges the external inductor and discharges
it into the 0.01 to 0.1µF, 100V capacitor at the CS pin. The volt-
age at the CS pin will start to increase. The outputs VA and VB
are configured as an H-bridge and are switching in opposite
states to achieve a peak-to-peak voltage of two times the V
CS
voltage across the EL lamp.
Applications
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Pagers
Portable Transceiver
Cellular phones
Remote control units
Calculators
HV825 Block Diagram
LX
VDD
CS
RSW-Osc
Switch
Osc
Q
VA
GND
Q
Output
Osc
Q
VB
REL-Osc
Q
HV825
Ordering Information
Device
HV825
Package Options
8-Lead SO
HV825LG
HV825LG-G
8-Lead MSOP
HV825MG
HV825MG-G
-G indicates package is RoHS compliant (‘Green’)
Absolute Maximum Ratings
Parameter
Supply voltage, V
DD
Operating Temperature Range
Storage Temperature Range
MSOP-8 Power Dissipation
SO-8 Power Dissipation
Value
0.5V to +2.5V
-25°C to +85°C
-65°C to +150°C
300mW
400mW
Pin Configuration
VDD
RSW-Osc
CS
LX
1
2
3
4
8
7
6
5
REL-Osc
VA
VB
GND
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.
HV825
(top view)
Electrical Characteristics
DC Characteristics
(Over recommended operating conditions unless otherwise specified
Symbol
R
DS(ON)
I
IN
I
DDQ
V
CS
V
A-B
f
EL
f
SW
D
Parameter
On-resistance of switching transistor
V
DD
supply current (including inductor
current)
Quiescent V
DD
supply current
Output voltage on V
CS
Differential output voltage across
lamp
V
A-B
output drive frequency
Switching transistor frequency
Switching transistor duty cycle
Min
-
-
-
52
104
400
-
-
Typ
-
30
-
56
112
-
30
88
Max
15
38
1.0
68
136
-
-
-
- T
A
=25°C)
Units
Ω
mA
μA
V
V
Hz
KHz
%
Conditions
I = 50mA
V
DD
=1.5V. See test circuit
R
SW-osc
= GND
V
DD
= 1.5V. See test circuit
V
DD
= 1.5V. See test circuit
V
DD
= 1.5V. See test circuit
V
DD
= 1.5V. See test circuit
---
Recommended Operating Conditions
V
DD
C
L
T
A
Supply voltage
Load Capacitance
Operating temperature
1.0
0
-25
-
6.0
-
1.6
-
+85
V
nF
O
---
---
---
C
Enable/Disable Table
V
IL
V
IH
Low level input voltage to R
SW-osc
resistor
High level input voltage to R
SW-osc
re-
sistor
0
V
DD
-0.5
-
-
0.2
V
DD
V
V
V
DD
= 1.0V-1.6V
V
DD
= 1.0V-1.6V
2
HV825
Test Circuit
ON = V
DD
OFF = GND
Enable
1MΩ
1
750KΩ
560µH
1
VDD
REL-Osc
VA
VB
GND
8
2.2KΩ
7
6
5
Equivalent to
1.5in
2
lamp
2
3
4
0.01µF
100V
C
SW
1nF
RSW-Osc
CS
LX
4.7nF
V
DD
= V
IN
= 1.0V - 1.6V
0.1µF
1N4148
HV825LG or
HV825MG
Typical Performance
Lamp Size
1.5in
2
V
IN
1.5V
I
DD
30mA
V
CS
56V
f
EL
450Hz
Brightness
3.65ft-lm
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
External Component Description
External
Component
Diode
C
S
Capacitor
R
EL-Osc
Resistor
Selection Guide Line
Fast reverse recovery, 1N4148 or equivalent.
0.01 to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor.
The lamp frequency is controlled via the R
EL-Osc
. The lamp frequency increases as the R
EL-Osc
decreases.
As the lamp frequency increases, the amount of current drawn from the battery will increase and the
output voltage V
CS
will decrease. This is because the lamp will draw more current from V
CS
when
driven at higher frequencies.
In general, as the lamp size increases, a larger R
EL-Osc
is recommended to provide higher V
CS
. However,
the color of the lamp is dependent upon its frequency and the shade of the color will change slightly
with different frequencies.
R
SW-Osc
Resistor
The switching frequency of the inductor is controlled via the R
SW-Osc
. The switching frequency increases
as the R
SW-Osc
decreases. As the switching frequency increases, the amount of current drawn from the
battery will decrease and the output voltage V
CS
will also decrease.
The inductor L
X
is used to boost up the low input voltage. When the internal switch is on, the inductor
is being charged. When the internal switch is off, the charge in the inductor will be transferred to the
high voltage capacitor C
S
. The energy stored in the capacitor is connected to the internal H-bridge and
therefore to the lamp. In general smaller value inductors, which can handle more current, are more
suitable to drive larger size lamps. As the inductor value decreases, the switching frequency of the
inductor (controlled by R
SW-Osc
) should be increased to avoid saturation.
The test circuit uses a Murata (LQH4N561) 560µH inductor. Using different inductor values or induc-
tors from different manufacturers will affect the performance.
As the inductor value decreases, smaller R
SW-Osc
values should be used. This will prevent inductor
saturation. An inductor with the same inductance value, (560µH), but lower series resistance, will
charge faster.
The R
SW-Osc
resistor value needs to be decreased to prevent inductor saturation and high current
consumption.
C
SW
Capacitor
A 1nF capacitor is recommended from RSW-Osc pin to GND. This capacitor is used to shunt any
switching noise that may couple into the RSW-Osc pin.
L
X
Inductor
3
HV825
8-Lead SOIC (Narrow Body) Package (LG)
4.90 ± 0.10
8
6.00 ± 0.20
3.90 ± 0.10
Note 2
Notes:
1. All dimensions in millimeters. Angles in degrees.
2. If the corner is not chamfered, then a Pin 1 identifier
must be located within the area indicated.
1
Top View
0.17 - 0.25
1.75 MAX
1.25 MIN
5° - 15°
(4 PLCS)
45°
0.25 - 0.50
Note 2
0° - 8°
0.10 - 0.25
1.27BSC
0.40 - 1.27
0.31 - 0.51
Side View
End View
4
HV825
8-Lead MSOP Package Outline (MG)
3x3mm body, 1.10mm height (max), 0.65mm pitch
D
8
θ1 (x4)
E
E1
Note 1
(Index Area
D1/2 x E1/2)
L
L2
Gauge
Plane
1
L1
θ
Seating
Plane
Top View
A
View B
View B
A
A2
Seating
Plane
A1
e
b
A
Side View
View A-A
Note 1:
A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier may be either a mold, or an embedded metal or marked feature.
Symbol
Dimen-
sion
(mm)
MIN
NOM
MAX
A
0.75
-
1.10
A1
0.00
-
0.15
A2
0.75
0.85
0.95
b
0.22
-
0.38
D
2.80
3.00
3.20
E
4.65
4.90
5.15
E1
2.80
3.00
3.20
e
0.65
BSC
L
0.40
0.60
0.80
L1
0.95
REF
L2
0.25
BSC
θ
0
O
-
8
O
θ1
5
O
-
15
O
JEDEC Registration MO-187, Variation AA, Issue E, Dec. 2004.
Drawings not to scale.
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline
information go to
http://www.supertex.com/packaging.html.)
Doc.# DSFP-HV825
A111306
5
