General Description
The Durel
®
D305A is a high-power IC inverter intended for
driving EL lamps as large as 100 cm
2
. The D305A IC is
equipped with many control functions, including: wave-
shaping
TM
programmability for minimizing audible noise, and
features that allow for component cost-savings, precision
control of frequencies, and stability of lamp color over wide
temperature extremes.
Data Sheet
D305A
Electroluminescent
Lamp Driver IC
D3
05
A
MSOP - 10
Features
•
•
•
•
•
High AC Voltage Output to 400Vpp
Very Low Standby Current
Flexible Wave-shaping Capability
External Clock Compatible
Small MSOP-10 Package
•
•
•
•
•
Applications
White EL Lamp Backlight for Color LCD
Wireless Handset
PDA
GPS
Other Handheld Portable Electronics
Lamp Driver Specifications
Parameter
Standby Current
Supply Current
Logic Supply Current
Output Voltage
Lamp Frequency
(Using Standard Test Circuit at Ta=25 °C unless otherwise specified.)
Symbol
Ibat
Icc
Vout
LF
Minimum
85
16
264
425
Typical
1
99
17
297
473
Maximum
5
115
19
330
525
Unit
mA
mA
Vpp
Hz
µA
Conditions
E = GND
E = Vcc
E = Vcc
E = Vcc
E = Vcc
Standard Test Circuit
BAS21
470uH / DCR = 1
Ω
1 Va
L
10
5V
100pF
Load B
2.2nF
(200V)
2
3
Cs
Vb
E
Vcc
D305A
GND 9
Rf
8
ON
OFF
10k
Ω
100k
Ω
4
5
3V
CLF 7
6.8nF
CHF 6
180pF
1
Load B*
47 nF
100Ω
10kΩ
22 nF
Typical Output Waveform
* Load B approximates a 5in
2
(32cm
2
) EL lamp.
Absolute Maximum Ratings
Parameter
Symbol
Supply Voltage
Operating Range
Vbat
Withstand Range
Logic Drive Voltage
Operating Range
Vcc
Withstand Range
Enable Voltage
E
Vout
Va - Vb
Operating Temperature
T
a
Operating Temperature
Tj
Average Thermal Resistance
θ
jA
Storage Temperature
T
s
Minimum
2.0
-0.5
2
-0.5
-0.5
-40
Maximum
7.0
16
5
6
Vcc + 0.5
410
85
125
113
150
Unit
V
V
V
Vpp
°C
°C
°C/W
°C
Comments
E = Vcc
E = GND
E = Vcc
E = GND
E = Vcc
Ambient
Junction
Junction to Ambient
-55
Note: The above are stress ratings only. Functional operation of the device at these ratings or any other above those indicated in the
specifications is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.
Physical Data
1
10
PIN # NAME
1
2
3
4
5
6
7
8
9
10
Va
Cs
Vb
E
Vcc
CHF
CLF
Rf
GND
L
FUNCTION
AC voltage output to EL lamp
High voltage storage capacitor input
AC voltage output to EL lamp
System enable; Wave-shaping resistor control
Logic drive voltage
Capacitor input to high frequency oscillator
Capacitor input to low frequency oscillator
Resistor input for frequency control
Power ground
Inductor input
2
9
3
8
4
7
5
6
2
Typical Performance Characteristics Using Standard Test Circuit
600
600
500
500
LF (Hz)
400
300
LF (Hz)
1
2
3
4
5
6
7
8
400
300
200
200
100
100
0
0
-40
-20
0
20
40
60
80
DC Input Voltage (V)
Temperature (°C)
Output Frequency vs. DC Supply Voltage
Output Frequency vs. Ambient Temperature
400
350
400
350
Output Voltage (Vpp)
250
200
150
100
50
0
1
2
3
4
5
6
7
8
Output Voltage (Vpp)
300
300
250
200
150
100
50
0
-40
-20
0
20
40
60
80
DC Input Voltage (V)
Temperature (°C)
Output Voltage vs. DC Supply Voltage
Output Voltage vs. Ambient Temperature
140
140
Avg Supply Current (mA)
100
Avg Supply Current (mA)
1
2
3
4
5
6
7
8
120
120
100
80
80
60
60
40
40
20
20
0
0
-40
-20
0
20
40
60
80
DC Input Voltage (V)
Temperature (°C)
Supply Current (Ibat)
vs. DC Supply Voltage
Supply Current (Ibat)
vs. Ambient Temperature
3
Block Diagram of the Driver Circuitry
Theory of Operation
Electroluminescent (EL) lamps are essentially capacitors with one transparent electrode and a special phosphor
material in the dielectric. When a strong AC voltage is applied across the EL lamp electrodes, the phosphor
glows. The required AC voltage is typically not present in most systems and must be generated from a low
voltage DC source.
The D305A IC inverter drives the EL lamp by using a switching transistor to repeatedly charge an external
inductor and discharge it to the high voltage capacitor Cs. The discharging causes the voltage at Cs to
continually increase. The internal circuitry uses the H-bridge technology, using both electrodes to drive the
EL lamp. One of the outputs, Va or Vb, is used to discharge Cs into the EL lamp during the first half of the
low frequency (LF) cycle. By alternating the state of the H-bridge, the other output is used to charge the EL
lamp during the second half of the LF cycle. The alternating states make it possible to achieve 400V peak-
to-peak across the EL lamp.
The EL driving system is divided into several parts: on-chip logic control, on-chip high voltage output
circuitry, on-chip discharge logic circuitry, and off-chip components. The on-chip logic controls the lamp
operating frequency (LF) and the inductor switching frequency (HF). These signals are used to drive the
high voltage output circuitry (H-bridge) by delivering the power from the inductor to the lamp. The integrated
discharge logic circuitry uses a patented wave shaping technique for reducing audible noise from an EL
lamp. Changing the Rd value changes the slope of the linear discharge as well as the shape of the waveform.
The off-chip component selection provides a degree of flexibility to accommodate various lamp sizes, system
voltages, and brightness levels.
Typical D305A EL driving configurations for driving EL lamps in various applications are shown on the
following page. The expected system outputs for the various circuit configurations are also shown with each
respective figure. These examples are only guides for configuring the driver. Durel provides a D305A
Designer's Kit, which includes a printed circuit evaluation board intended to aid you in developing an EL
lamp driver configuration using the D305A that meets your requirements. A section on designing with the
D305A is included in this datasheet to serve as a guide to help you select the appropriate external components
to complete your D305A EL driver system.
4
Typical D305A EL Driver Configurations
Handset Color LCD Backlight
Typical Output
Brightness = 19.5 fL (66 cd/m
2
)
White
Lamp Frequency = 500 Hz
EL Lamp
Logic Supply Current = 20 mA
Power Supply Current = 66 mA
Vout = 310 Vpp
Load = 2 in
2
(12.9 cm
2
) Durel
®
3 White EL
1 Va
2.2 nF
(200 V)
BAS21
220 uH Sumida CLS62
L
10
100pF
3.3 V
2
3
Cs
Vb
E
Vcc
D305A
GND 9
Rf
8
ON
OFF
10 k
Ω
100k
Ω
5.6 nF
4
5
CLF 7
CHF 6
180 pF
3.3V
PDA Display
Typical Output
Brightness = 18.5 fL (63 cd/m )
Lamp Frequency = 358 Hz
PDA LCD
Logic Supply Current = 18 mA
EL Lamp
Power Supply Current = 87 mA
Vout = 408 Vpp
Load = 5 in
2
(32.2 cm
2
) Durel
®
3 Green EL
2
BAS21
470 uH TDK SLF7032
1 Va
2.2 nF
(200 V)
L
10
100pF
5.0 V
2
3
Cs
Vb
E
Vcc
D305A
GND 9
Rf
8
ON
OFF
10 k
Ω
100k
Ω
4
5
CLF 7
8.2 nF
CHF 6
180 pF
3.0 V
Bright Blue Backlight for LCD
Typical Output
Brightness = 21.5 fL (73 cd/m )
Bright Blue
Lamp Frequency = 415 Hz
EL Lamp
Logic Supply Current = 19 mA
Power Supply Current = 68 mA
Vout = 408 Vpp
Load = 1 in
2
(6.5 cm
2
) Durel
®
3 Blue EL
2
BAS21
220 uH Coilcraft LPO2506
1 Va
2.2 nF
(200 V)
L
10
100pF
3.6 V
2
3
Cs
Vb
E
Vcc
D305A
GND 9
Rf
8
ON
OFF
10 k
Ω
100k
Ω
4
5
CLF 7
6.8 nF
CHF 6
180 pF
3.0 V
5
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