SUTEX HV823X High voltage el lamp driver Datasheet

HV823
HV823
High Voltage EL Lamp Driver
Ordering Information
Package Options
Device
Input Voltage
8-Lead SO
Die
HV823
2.0V to 9.5V
HV823LG
HV823X
Features
General Description
❏
Processed with HVCMOS® technology
❏
2.0V to 9.5V operating supply voltage
❏
DC to AC conversion
❏
180V peak-to-peak typical output voltage
❏
Large output load capability typically 50nF
❏
Permits the use of high-resistance elastomeric lamp
components
❏
Adjustable output lamp frequency to control lamp color,
lamp life, and power consumption
❏
Adjustable converter frequency to eliminate harmonics and
optimize power consumption
❏
Enable/disable function
❏
Low current draw under no load condition
Handheld personal computers
❏
Electronic personal organizers
❏
GPS units
❏
Pagers
❏
Cellular phones
❏
Portable instrumentation
Pin Configuration
ςΑ
Absolute Maximum Ratings*
Supply Voltage, VDD
-0.5V to +10V
Output Voltage, VCs
-0.5V to +120V
Operating Temperature Range
-25°C to +85°C
Storage Temperature Range
Power Dissipation
The HV823 has two internal oscillators, a switching MOSFET,
and a high-voltage EL lamp driver. The frequency for the switching converter MOSFET is set by an external resistor connected
between the RSW-osc pin and the supply pin VDD. 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 0.01µF to 0.1µF
capacitor is connected between CS and GND. The EL lamp is
connected between VA and VB.
The switching MOSFET charges the external inductor and
discharges it into the Cs capacitor. The voltage at Cs will start to
increase. Once the voltage at Cs reaches a nominal value of 90V,
the switching MOSFET is turned OFF to conserve power. The
outputs VA and VB are configured as an H-bridge and are
switched in opposite states to achieve 180V peak-to-peak across
the EL lamp.
Applications
❏
The Supertex HV823 is a high-voltage driver designed for driving
EL lamps of up to 50nF. EL lamps greater than 50nF can be
driven for applications not requiring high brightness. The input
supply voltage range is from 2.0 to 9.5V. 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 ±90V. The chip can be enabled by connecting the resistors on
RSW-osc and REL-osc to VDD and disabled when connected to GND.
-65°C to +150°C
VDD
1
8
REL-osc
RSW-osc
2
7
VA
Cs
3
6
VB
Lx
4
5
GND
SO-8
400mW
Note:
*All voltages are referenced to GND.
11/12/01
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 "products liability
indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be 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
1 refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.
Supertex website: http://www.supertex.com. For complete liability information on all Supertex products,
HV823
Electrical Characteristics
DC Characteristics (VIN = 3.0V, RSW = 750KΩ, REL = 2.0MΩ, TA = 25°C unless otherwise specified)
Symbol
Parameter
Min
Typ
Max
Units
Conditions
2
6
Ω
I = 100mA
80
90
100
V
VIN = 2.0 to 9.5V
160
180
200
V
VIN = 2.0V to 9.5V
Quiescent VDD supply current, disabled
30
100
nA
RSW-osc = Low
Input current going into the VDD pin
150
200
µA
VIN = 3.0V. See Figure 1.
300
µA
VIN = 5.0V. See Figure 2.
500
µA
VIN = 9.0V. See Figure 3.
25
33
mA
VIN = 3.0V. See Figure 1.
RDS(on)
On-resistance of switching transistor
VCS
Output voltage VCS Regulation
VA - VB
Output peak to peak voltage
IDDQ
IDD
IIN
Input current including inductor current
VCS
Output voltage on VCS
60
70
85
V
VIN = 3.0V. See Figure 1.
fEL
VA-B output drive frequency
330
380
450
Hz
VIN = 3.0V. See Figure 1.
fSW
Switching transistor frequency
50
60
70
KHz
VIN = 3.0V. See Figure 1.
D
Switching transistor duty cycle
88
%
Recommended Operating Conditions
Symbol
Parameter
Min
Typ
Max
Units
VDD
Supply voltage
2.0
9.5
V
TA
Operating temperature
-25
+85
°C
Enable/Disable Table
(See Figure 4)
RSW resistor
HV823
VDD
Enable
0V
Disable
2
Conditions
HV823
Block Diagram
Lx
VDD
Cs
RSW-osc
Switch
Osc
Enable *
Q
VA
GND
+
C
_
Disable
Q
Vref
Output
Osc
Q
VB
REL-osc
Q
* Enable is available in die form only.
Figure 1: Test Circuit, VIN = 3.0V
(Low input current with moderate output brightness).
ON = VDD
2MΩ
OFF = 0V
1
VDD
REL-osc
8
2
RSW-osc
VA
7
3
Cs
VB
6
4
Lx
GND
5
750KΩ
560µH
1
VDD = VIN = 3.0V
1N4148
0.1µF
10nF
2
0.1µF
2.0KΩ
Equivalent to 3 square inch lamp.
HV823
100V
Typical Performance
Lamp Size
3.0
in2
VIN
IIN
VCS
fEL
Brightness
3.0v
25mA
65v
385Hz
6.5ft-lm
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
3
HV823
Typical Performance Curves for Figure 1 using 3in2 EL Lamp.
IIN vs. VIN
30
80
25
70
20
IIN (mA)
90
60
50
40
2
3
4
5
6
7
8
15
10
5
0
9
1
2
3
4
5
6
VIN (V)
Brightness vs. VIN
IIN vs. VCS (V)
12
10
8
6
4
2
0
1
2
VIN (V)
3
4
5
6
7
8
40
9
50
VIN (V)
60
70
VCS (V)
IIN, VCS, Brightness vs. Inductor Value
90
9.0
80
8.0
70
7.0
VCS(V)
6.0
50
5.0
4.0
Brightness (ft-lm)
30
3.0
20
2.0
IIN(mA)
10
1.0
0
0
100
250
400
550
Inductor Value (µH)
4
700
850
1000
Brightness (ft-Im)
60
40
7
8
9
30
25
20
15
10
5
0
IIN (mA)
Brightness (ft-Im)
1
IIN (mA), VCS (V)
Vcs (V)
VCS vs. VIN
80
90
HV823
Figure 2: Typical 5.0V Application
ON = VDD
2MΩ
OFF = 0V
1
VDD
REL-osc
8
2
RSW-osc
VA
7
3
Cs
VB
6
4
Lx
GND
5
750KΩ
560µH
1
VDD = VIN = 5.0V
1N4148
0.1µF
3.1KΩ
20nF
Equivalent to 6 square inch lamp
2
0.01µF
1nF
100V
16v
HV823
Typical Performance
Lamp Size
6.0
in2
VIN
IIN
VCS
fEL
Brightness
5.0v
25mA
75v
380Hz
6.5ft-lm
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
Typical Performance Curves for Figure 2
VCS vs. VIN
IIN vs. VIN
90
80
IIN (mA)
VCS (V)
85
75
70
65
4
5
6
VIN (V)
7
40
38
36
34
32
30
4
8
5
6
VIN (V)
8
85
90
IIN vs. VCS (V)
IIN (mA)
Brightness (ft-Im)
Brightness vs. VIN
5
7
VIN (V)
8
7.5
7
6.5
6
5.5
4
6
7
8
40
38
36
34
32
30
70
75
80
VCS (V)
5
HV823
Figure 3: Typical 9.0V Application*
2MΩ
1
VDD
REL-osc
8
2
RSW-osc
VA
7
3
Cs
VB
6
4
Lx
GND
5
330KΩ
560µH1
VDD = VIN = 9.0V
1N4148
4.9KΩ
42nF
Equivalent to 12 square inch lamp
0.1µF2
1nF
16v
0.01µF
100V
HV823
Typical Performance
Lamp Size
VIN
IIN
VCS
fEL
Brightness
12.0 in2
9.0v
30mA
75v
380Hz
8.5ft-lm
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
Typical Performance Curves for Figure 3
VCS vs. VIN
IIN vs. VIN
85
IIN (mA)
VCS (V)
80
75
70
65
4
5
6
VIN (V)
7
40
38
36
34
32
30
4
8
5
8
7.5
7
6.5
6
5.5
5
6
7
8
85
90
IIN vs. VCS (V)
IIN (mA)
Brightness (ft-Im)
Brightness vs. VIN
4
6
VIN (V)
7
8
VIN (V)
40
38
36
34
32
30
70
75
80
VCS (V)
6
HV823
External Component Description
External Component
Selection Guide Line
Diode
Fast reverse recovery diode, 1N4148 or equivalent.
Cs Capacitor
0.01µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor.
REL-osc
The EL lamp frequency is controlled via an external REL resistor connected between REL-osc and VDD of the
device. The lamp frequency increases as REL decreases. As the EL lamp frequency increases, the amount
of current drawn from the battery will increase and the output voltage VCS will decrease. The color of the EL
lamp is dependent upon its frequency.
A 2MΩ resistor would provide lamp frequency of 330 to 450Hz. Decreasing the REL-osc by a factor of 2 will
increase the lamp frequency by a factor of 2.
RSW-osc
The switching frequency of the converter is controlled via an external resistor, RSW between RSW-osc and VDD
of the device. The switching frequency increases as RSW decreases. With a given inductor, as the switching
frequency increases, the amount of current drawn from the battery will decrease and the output voltage, VCS,
will also decrease.
CSW Capacitor
A 1nF capacitor is recommended on RSW-osc to GND when a 0.01µF CS capacitor is used. This capacitor
is used to shunt any switching noise that may couple into the RSW-osc pin. The CSW capacitor may also be
needed when driving large EL lamp due to increase in switching noise.
Lx Inductor
The inductor Lx is used to boost the low input voltage by inductive flyback. When the internal switch is on,
the inductor is being charged. When the internal switch is off, the charge stored in the inductor will be
transferred to the high voltage capacitor CS. The energy stored in the capacitor is connected to the internal
H-bridge and therefore to the EL 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 RSW) should be increased to avoid saturation.
560µH Murata inductors with 14.5Ω series DC resistance is typically recommended. For inductors with the
same inductance value but with lower series DC resistance, lower RSW value is needed to prevent high current
draw and inductor saturation.
Lamp
As the EL lamp size increases, more current will be drawn from the battery to maintain high voltage across
the EL lamp. The input power, (VIN x IIN), will also increase. If the input power is greater than the power
dissipation of the package (400mW), an external resistor in series with one side of the lamp is recommended
to help reduce the package power dissipation.
Enable/Disable Configuration
The HV823 can be easily enabled and disabled via a logic control
signal on the RSW and REL resistors as shown in Figure 4 below.
The control signal can be from a microprocessor. RSW and REL
are typically very high values. Therefore, only 10’s of microam-
peres will be drawn from the logic signal when it is at a logic high
(enable) state. When the microprocessor signal is high the
device is enabled and when the signal is low, it is disabled.
Figure 4: Enable/Disable Configuration
Remote
Enable
ON =VDD
OFF = 0V
REL
1
VDD
REL-osc
8
2
RSW-osc
VA
7
3
Cs
VB
6
4
Lx
GND
5
RSW
Lx
+
VIN = VDD
-
1N4148
4.7µF
15V
EL Lamp
HV823LG
CS
100V
1nF
7
HV823
Split Supply Configuration Using a Single
Cell (1.5V) Battery
Split Supply Configuration for Battery
Voltages of Higher than 9.5V
The HV823 can also be used for handheld devices operating
from a single cell 1.5V battery where a regulated voltage is
available. This is shown in Figure 5. The regulated voltage
can be used to run the internal logic of the HV823. The
amount of current necessary to run the internal logic is
typically 100µA at a VDD of 3.0V. Therefore, the regulated
voltage could easily provide the current without being loaded
down. The HV823 used in this configuration can also be
enabled/disabled via logic control signal on the RSW and REL
resistors as shown in Figure 4.
Figure 5 can also be used with high battery voltages such as 12V
as long as the input voltage, VDD, to the HV823 device is within
its specifications of 2.0V to 9.5V.
Figure 5: Split Supply Configuration
Remote
Enable
ON =VDD
OFF = 0
REL
VDD = Regulated
Voltage
1
VDD
2
RSW-osc
3
Cs
VB
6
4
Lx
GND
5
RSW
Lx
+
VIN = Battery
Voltage
-
1N4148
REL-osc
8
VA
7
EL Lamp
0.1µF*
HV823LG
CS
100V
*Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
11/12/01
©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
8
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 744-0100 • FAX: (408) 222-4895
www.supertex.com
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