ChipFind - документация

Электронный компонент: D305A

Скачать:  PDF   ZIP
1
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.
High AC Voltage Output to 400Vpp
White EL Lamp Backlight for Color LCD
Very Low Standby Current
Wireless Handset
Flexible Wave-shaping Capability
PDA
External Clock Compatible
GPS
Small MSOP-10 Package
Other Handheld Portable Electronics
Features
Applications
Standard Test Circuit
E = GND
mA
E = Vcc
mA
E = Vcc
Vpp
E = Vcc
Hz
E = Vcc
Parameter
Symbol
Minimum
Typical
Maximum
Unit
Conditions
(Using Standard Test Circuit at Ta=25 C unless otherwise specified.)
Lamp Driver Specifications
Data Sheet
D305A
Electroluminescent
Lamp Driver IC
MSOP - 10
D305A
Standby Current
1
5
Supply Current
Ibat
85
99
115
Logic Supply Current
Icc
16
17
19
Output Voltage
Vout
264
297
330
Lamp Frequency
LF
425
473
525
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2nF
(200V)
180pF
100k
100pF
3V
6.8nF
BAS21
470uH / DCR = 1
Load B
5V
10k
A
2
PIN # NAME
FUNCTION
Typical Output Waveform
Load B*
Physical Data
* Load B approximates a 5in
2
(32cm
2
) EL lamp.
100
22 nF
10k
47 nF
1
2
3
4
5
10
9
8
7
6
Absolute Maximum Ratings
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.
Parameter
Symbol
Minimum
Maximum
Unit
Comments
Supply Voltage
Operating Range
Vbat
2.0
7.0
V
E = Vcc
Withstand Range
-0.5
16
E = GND
Logic Drive Voltage
Operating Range
Vcc
2
5
V
E = Vcc
Withstand Range
-0.5
6
E = GND
Enable Voltage
E
-0.5
Vcc + 0.5
V
Vout
Va - Vb
410
Vpp
E = Vcc
Operating Temperature
T
a
-40
85
C
Ambient
Operating Temperature
Tj
125
C
Junction
Average Thermal Resistance
jA
113
C/W
Junction to Ambient
Storage Temperature
T
s
-55
150
C
1
Va
AC voltage output to EL lamp
2
Cs
High voltage storage capacitor input
3
Vb
AC voltage output to EL lamp
4
E
System enable; Wave-shaping resistor control
5
Vcc
Logic drive voltage
6
CHF
Capacitor input to high frequency oscillator
7
CLF
Capacitor input to low frequency oscillator
8
Rf
Resistor input for frequency control
9
GND
Power ground
10
L
Inductor input
3
Typical Performance Characteristics Using Standard Test Circuit
Output Frequency vs. DC Supply Voltage
Output Frequency vs. Ambient Temperature
Output Voltage vs. DC Supply Voltage
Output Voltage vs. Ambient Temperature
Supply Current (Ibat)
vs. DC Supply Voltage
Supply Current (Ibat)
vs. Ambient Temperature
0
100
200
300
400
500
600
-40
-20
0
20
40
60
80
LF (Hz)
Temperature (
C)
0
20
40
60
80
100
120
140
-40
-20
0
20
40
60
80
Temperature (
C)
Avg Supply Current (mA)
0
50
100
150
200
250
300
350
400
-40
-20
0
20
40
60
80
Temperature (
C)
Output Voltage (Vpp)
0
100
200
300
400
500
600
1
2
3
4
5
6
7
8
LF (Hz)
DC Input Voltage (V)
0
50
100
150
200
250
300
350
400
1
2
3
4
5
6
7
8
DC Input Voltage (V)
Output Voltage (Vpp)
0
20
40
60
80
100
120
140
1
2
3
4
5
6
7
8
DC Input Voltage (V)
Avg Supply Current (mA)
4
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.
Block Diagram of the Driver Circuitry
5
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
180 pF
10 k
100k
100pF
3.0 V
6.8 nF
BAS21
220 uH Coilcraft LPO2506
Bright Blue
EL Lamp
3.6 V
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
180 pF
10 k
100k
100pF
3.3V
5.6 nF
BAS21
220 uH Sumida CLS62
White
EL Lamp
3.3 V
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
180 pF
10 k
100k
100pF
3.0 V
8.2 nF
BAS21
470 uH TDK SLF7032
PDA LCD
EL Lamp
5.0 V
Typical D305A EL Driver Configurations
Handset Color LCD Backlight
Typical Output
Brightness = 19.5 fL (66 cd/m
2
)
Lamp Frequency = 500 Hz
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
PDA Display
Typical Output
Brightness = 18.5 fL (63 cd/m
2
)
Lamp Frequency = 358 Hz
Logic Supply Current = 18 mA
Power Supply Current = 87 mA
Vout = 408 Vpp
Load = 5 in
2
(32.2 cm
2
) Durel
3 Green EL
Bright Blue Backlight for LCD
Typical Output
Brightness = 21.5 fL (73 cd/m
2
)
Lamp Frequency = 415 Hz
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
6
Designing With D305A
There are many variables which can be optimized to achieve the desired performance for specific applications.
The luminance of the EL lamp is a function of the output voltage applied to the lamp by the IC, the frequency
at which the voltage is applied, the lamp material properties, and the lamp size. Durel offers the following
component selection aids to help the designer select the optimum circuit configuration.
I. Lamp Frequency Capacitor (CLF) Selection
Selecting the appropriate value of capacitor (CLF) for the low frequency oscillator will set the output frequency
of the D305A EL driver IC. Figure 1 graphically represents the effect of the CLF capacitor value on the
oscillator frequency at Vbat = Vcc = 3.0V.
Figure 1: Typical Lamp Frequency vs. CLF Capacitor
Figure 2: Typical Inductor Frequency vs. CHF Capacitor
0
200
400
600
800
1000
1200
1400
1
3
5
7
9
11
13
15
CLF (nF)
Lamp Frequency (Hz)
II. Inductor Switching Frequency (CHF) Selection
Selecting the appropriate value of capacitor (CHF) for the high frequency oscillator will set the inductor
switching frequency of the D305A inverter. Figure 2 graphically represents the effect of the CHF capacitor
value on the oscillator frequency at Vbat = Vcc = 3.0V.
15
20
25
30
35
40
45
100
150
200
250
300
350
CHF (pF)
Inductor Frequency (kHz)
7
The inductor value has a large impact on the output brightness and current consumption of the driver. Figure
3 shows typical brightness and current draw of a D305A circuit with different inductor values. Please note
that the DC resistance (DCR) and current rating of inductors with the same inductance value may vary with
manufacturer and inductor type. Thus, inductors made by a different manufacturer may yield different
outputs, but the trend of the different curves should be similar. This curve is intended to give the designer a
relative scale from which to optimize specific applications. Absolute measurements may vary depending
upon the type and brand of other external components selected.
III. Inductor (L) Selection
IV. Wave-Shape Selection
The D305A EL driver IC uses a patented wave-shaping technique for reducing audible noise from an EL
lamp. The slope of the discharge section of the output waveform may be adjusted by selecting a proper value
for the wave-shape discharge resistor (Rd) in series with the E pin input. The optimal discharge level for an
application depends on the lamp size, lamp brightness, and application conditions. To ensure that the D305A
is configured optimally, various discharge levels should be evaluated. In many cases, lower discharge levels
may result in lower audible noise from the EL lamp. The recommended typical value for Rd is 10 k
.
V. Storage Capacitor (Cs) Selection
The Cs capacitor is used to store the energy transferred from the inductor before discharging the energy to
the EL lamp. Cs values can range from 1.5nF to 4.7nF and must have minimum 200V rating. In general, the
Cs value does not have a large affect on the output of the device. The typical Cs capacitor recommendation
is 2.2nF with 200V rating.
VI. Rf and CRf Selection
The combination of Rf and the timing capacitors, CLF and CHF, determines the time constants for the low
frequency oscillator and the high frequency oscillator, respectively. To simplify the tuning of the oscillator
frequencies to the desired frequency range, a standard value is recommended for Rf = 100 k
.
The CRf capacitor is used as a stabilizing capacitor to filter noise on the Rf line. A small 100pF capacitor is
typical and sufficient value for CRf.
Figure 3: Brightness and current vs. inductor value
Conditions: Vcc = Vbat = 3.3V, 12.9 cm
2
EL Lamp
0
5
10
15
20
25
0
500
1000
1500
2000
2500
Inductor (H)
Lum
i
n
a
n
c
e
(
f
L
)
0
20
40
60
80
100
Cu
r
r
e
n
t
Dr
a
w
(
m
A)
Luminance
Current
Draw
8
VII. Fast Recovery Diode
Energy stored by the coil is eventually forced through the external diode to power the switched H-bridge
network. A fast recovery diode, such as BAS21, is recommended for this function for optimum operation.
VIII. Printed Circuit Board Layout
The high frequency operation and very high voltage output of the D305A makes printed circuit board layout
important for minimizing electrical noise. Maintain the IC connections to the inductor as short as possible.
Connect the GND of the device directly to the GND plane of the PCB. Keep the GND pin of the device and
the ground leads of the Cs, CLF, and CHF less than 5mm apart. If using bypass capacitors to minimize ripple
on the supply lines, keep the bypass caps as close as possible to the Vbat lead of the inductor and the Vcc pin.
IX. Split Voltage Supply
A split supply voltage is recommended to drive the D305A. To operate the on-chip logic, a regulated voltage
supply (Vcc) ranging from 2.0V to 6.5V is applied. To supply the D305A with the necessary power to drive
an EL lamp, another supply voltage (Vbat) with higher current capability is applied to the inductor. The
voltage range of Vbat is determined by the following conditions: user application, lamp size, inductor selection,
and power limitations of the battery.
An example of the split supply configuration is shown below. This example shows a regulated 3.0V applied
to the Vcc pin, and a Vbat voltage that may range from 3.6V to 6.2V or regulated at 5.0V. The enable voltage
is in the range of 2.0V to 3.0V. This is a typical setup used in PDA applications.
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
180 pF
10 k
100k
100pF
3.0 V
8.2 nF
BAS21
470 uH TDK SLF7032
PDA LCD
EL Lamp
3.6V - 6.2V Battery
or 5.0V Regulated
9
D305A Design Ideas
I. Controlling Output Frequency Using External Clock Signals
External clock signals may be used to control the D305A oscillator frequencies instead of adding external
passive components. When clocking signals provide both the inductor charging (HF) and lamp output (LF)
oscillator frequencies to drive the D305A, the CLF, CHF, Rf, and CRf components are no longer required.
A sample configuration demonstrating this cost-saving option is shown below.
In this configuration, the lamp frequency is controlled by the signal applied to the CLF pin. An internal
divider network in the IC divides the frequency of the LF input signal by two. Thus, to get a 400 Hz AC
output waveform to drive the EL lamp, an 800 Hz square-wave input signal should be connected to the CLF
pin. Input clocking frequencies may range from 400 Hz to 2000 Hz, with 15-20% positive duty cycle for
optimum brightness. The amplitude of the clock signal typically ranges from 1.0V to Vcc.
The high frequency oscillator that determines inductor charging frequency is controlled above by a digital
AC signal into the CHF pin. The HF clock signal frequency may range from 20KHz - 35KHz, with 15-20%
positive duty cycle for optimum lamp intensity. The amplitude of the clock signal typically ranges from
1.0V to Vcc.
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
10 k
3.0 V
BAS21
EL Lamp
3.3 V
800 Hz
15% + duty
1.0V Min
0.2V Max
1.0V Min
0.2V Max
27 KHz
15% + duty
II. Controlling EL Brightness through Clock Pulse Width Modulation (Option 1)
Pulse width modulation of the external LF input signal may be used to regulate the brightness of the EL
lamp. Figures 4, 5, and 6 below demonstrate examples of the D305A output waveform with pulse width
modulation of the LF input signal. As the positive duty cycle of the LF input signal is increased from 15% to
100%, the charging period of the output waveform decreases, and the peak voltage of the output waveform
also decreases towards zero output. Therefore, incremental dimming occurs as a result of the wave-shaping
changes. This scheme may also be used inversely to regulate lamp brightness over the life of the battery or
to compensate for lamp aging. Figure 7 shows a typical dimming curve with this technique. Operation at
duty cycles lower than 10% is not recommended. Clocking frequency can range from 400 Hz to 2000 Hz.
The maximum amplitude of the clock signal may range from 1.0V to Vcc.
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
10 k
3.0 V
BAS21
EL Lamp
800 Hz
15% to 100%
positive duty PWM
1.0V Min
0.2V Max
1.0V Min
0.2V Max
27 KHz
15% + duty
Figure 4: LF Input Duty Cycle = +15%
Figure 5: LF Input Duty Cycle = +50%
Figure 6: LF Input Duty Cycle = +75%
10
Figure 7: Dimming through LF Clock Input Duty Cyle
0
2
4
6
8
10
12
14
16
18
20
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
LF Clock Input Duty Cycle
L
u
m
i
n
an
ce (
f
L
)
0
20
40
60
80
100
Cu
rr
en
t
D
r
aw

(
m
A)
Luminance
Current
III. Controlling EL Brightness through Clock Pulse Width Modulation (Option 2)
Pulse width modulation of the external HF input signal also may be used to regulate the brightness of the EL
lamp. As the positive duty cycle of the LF input signal is increased from 15% to 100%, the peak voltage of
the output waveform decrease incrementally to zero output as the inductor charging period is affected by the
HF duty cycle. Lamp dimming is thus achieved with pulse width modulation of the HF input signal to the
D305A. This scheme may also be used inversely to regulate lamp brightness over the life of the battery or to
compensate for lamp aging. Figure 8 shows a typical dimming curve with this technique. The recommended
HF duty cycle range is from 10% to 95%. Clocking frequency can range from 20 KHz to 35 KHz. The
maximum amplitude of the clock signal may range from 1.0V to Vcc.
Va
Cs
Vb
E
Vcc
L
GND
Rf
CLF
CHF
D305A
1
2
3
4
5
10
9
8
7
6
OFF
ON
2.2 nF
(200 V)
10 k
3.0 V
BAS21
EL Lamp
800 Hz
15% positive duty
1.0V Min
0.2V Max
1.0V Min
0.2V Max
27 KHz
15% to 100%
positive duty PWM
11
0
5
10
15
20
25
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
CHF Clock Input Duty Cycle
0
20
40
60
80
100
Luminance
Current
Luminance (fL)
Figure 8: Dimming through HF Clock Input Duty Cyle
The D305A IC is available in standard MSOP-10 plastic package per tape and reel. A Durel D305A Designer's
Kit (1DDD305AA-K01) provides a vehicle for evaluating and identifying the optimum component values
for any particular application using D305A. Durel engineers also provide full support to customers including
specialized circuit optimization and application retrofits upon request
Ordering Information:
DUREL Corporation
2225 W. Chandler Blvd.
Chandler, AZ 85224-6155
Tel: (480) 917-6000
FAX: (480) 917-6049
Website: http://www.durel.com
2002 Durel Corporation
Printed in U.S.A.
LIT-I 9046 Rev. A02
The DUREL name and logo are registered trademarks of DUREL CORPORATION. Wave-shaping is a trademark of Durel Corporation.
This information is not intended to and does not create any warranties, express or implied, including any warranty of merchantability or fitness
for a particular purpose. The relative merits of materials for a specific application should be determined by your evaluation.
This driver IC is covered by the following U.S. patents: #5,313,141, #5,789,870, #6,297,597 B1. Corresponding foreign patents are issued and
pending.
ISO 9001 Certified
MSOPs in Tape and Reel: 1DDD305AA-M04
RECOMMENDED PAD LAYOUT
Embossed tape on 360 mm diameter reel
Quantity marked on reel label.
F
H
I
A
B
G
C
D
E
Tape Orientation
MSOPs are marked with part number (305A) and 3-digit wafer lot code. Bottom
of marking is on the Pin 1 side.
A
0.92
0.036
1.00
0.039
1.08
0.043
B
0.05
0.002
0.10
0.004
0.15
0.006
C
0.15
0.006
0.23
0.009
0.31
0.012
D
0.40
0.016
0.55
0.022
0.70
0.028
E
0.13
0.005
0.18
0.007
0.23
0.009
F
2.90
0.114
3.00
0.118
3.10
0.122
G
0.35
0.014
0.50
0.020
0.65
0.026
H
4.75
0.187
4.90
0.193
5.05
0.199
I
2.90
0.114
3.00
0.118
3.10
0.122
Description
mm.
in.
mm.
in.
mm.
in.
MSOP-10
Min.
Typical
Max.
mm.
in.
mm.
in.
mm.
in.
Min.
Typical
Max.
a
0.5
0.0197
b
2.0
0.0788
c
3.3
0.130
3.45
0.136
d
0.89
0.035
0.97
0.038
1.05
0.041
e
5.26
0.207
5.41
0.213
f
0.3
0.012
MSOP-10 PAD LAYOUT
e
c
a
b
d
f