IMP525

IMP525
POWER MANAGEMENT
Single Cell Battery Powered
Electroluminescent Lamp
Driver/Inverter
Key Features
◆ Wide operating voltage range - from 0.9V to 2.5V
◆ Simple design requires few passive components
◆ 112V peak-to-peak typical AC output voltage
The IMP525 is an Electroluminescent (EL) lamp driver designed for systems that must operate down to 1 volt and below. The input supply voltage range is 0.9V to 2.5V. Typical output lamp drive voltage is 112V. All
four EL lamp-driving functions are on-chip. These are the switch-mode
power supply, its high-frequency oscillator, the high-voltage H-bridge
lamp driver and its low-frequency oscillator. EL lamps of up to 6nF
capacitance can be driven to high brightness.
◆ Adjustable output frequency controls lamp
color and power consumption
The circuit requires few external components; one inductor, one diode,
one capacitor and two resistors. The resistors set the frequency for the
two oscillators.
◆ Compact MicroSO package option
A disable mode puts the chip into a low current-drain state. When disabled, quiescent current drops to 1µA typical with a VDD of 1.5V. The chip
can be disabled by connecting RSW, the oscillator frequency setting
resistor, to ground. A disable pad (active low), accessible only on the die,
can also be used to disable the driver.
An internal circuit shuts down the switching regulator when the lamp
drive voltage exceeds 112V peak-to-peak. This conserves power and
extends battery life.
The IMP525 is available in MicroSO and SO-8 packages and in die form.
Block Diagram
VDD
RSW-OSC
GND
◆ Adjustable converter frequency minimizes
circuit power consumption
◆ Disable mode extends battery life
◆ Disable current 1µA typical
Applications
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
◆
Audio/TV remote control units
Pagers/Cellular phones
PDAs
Clocks and radios
Portable GPS receivers
LCD modules
Toys
4
1
2
3
Switch
Oscillator
LX
CS
5
Q
+
7
C
Regulation
Control
–
VREF
VA
Q
Bridge
Output
Driver
IMP525
Q
6
REL-OSC
8
Lamp Drive
Oscillator
VB
Q
525_01.eps
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Electroluminescent Lamp Driver
1
IMP525
Pin Configuration
SO/MicroSO
VDD
1
IMP525
8
REL-OSC
7
VA
RSW-OSC
2
CS
3
6
VB
LX
4
5
GND
525_02.eps
Ordering Information
Part Number
Input Voltage
Regulated Output Voltage
Temperature Range
Pins-Package
IMP525EMA
0.9V to 2.5V
YES
– 40°C to +85°C
8-MicroSO
IMP525ESA
IMP525/D*
IMP525/D1**
0.9V to 2.5V
0.9V to 2.5V
0.9V to 2.5V
YES
YES
YES
– 40°C to +85°C
25°C
25°C
8-SO
Dice
Dice
* Disable pad not active
** Disable pad active
Add /T to ordering part number for Tape and Reel.
Absolute Maximum Ratings
Supply Voltage, VDD, VRSW-OSC and VREL-OSC . . – 0.5V to +3.5V
Storage Temperature Range . . . . . . . . . . . . . . . . – 65°C to +150°C
Power Dissipation (SO package) . . . . . . . . . . . . 400mW
Power Dissipation (MicroSO package) . . . . . . . 300mW
Note: All voltages are referenced to GND.
These are stress ratings only and functional operation is not implied.
Exposure to absolute maximum ratings for prolonged time periods may
affect device reliability.
Electrical Characteristics
Unless otherwise noted, VDD = 1.5V, RSW = 1MΩ, REL = 1.0MΩ, and TA = 25°C.
Parameter
Symbol
ON-resistance of MOS Switch
Operating Voltage
Output Voltage at CS
Output Voltage at CS
Output Voltage Peak-to-Peak
Quiescent VDD Supply Current, Disabled
(Disable pin available on die only)
Quiescent VDD Supply Current, Disabled
RDS(ON)
Input Current at VDD Pin
Input Current: IDD Plus Inductor Current
VA-B Output Drive Frequency
Boost Converter Switching Frequency
Switching Duty Cycle
Disable Input LOW Voltage
(Disable pin available on die only)
Disable Input HIGH Voltage
(Disable pin available on die only)
IDD
IIN
fEL
fSW
DSW
VDISL
2
Conditions
Min
Typ
I = 50mA
VCS
VCS
VA-VB
IQDIS
VDD = 1.5V, See Figure 1, Table 1
VDD = 0.9V, See Figure 1, Table 2
VDD = 1.5V, See Figure 1
Disable = HIGH
IQDIS
RSW-OSC = GND
VDD = 1.5V
VDD = 0.9V to 1.5V
VDD = 1.5V
VDD = 1.5V, See Figure 1, Table 1
VDD = 1.5V, See Figure 1, Table 1
VDD = 1.5V, See Figure 1
VDISH
© Daily Silver IMP
0.9
52
104
58
50
112
70
1.0
Max
Units
15
2.5
65
Ω
V
V
V
VP-P
nA
124
2.0
µA
1.5
32
GND
0.2
mA
mA
Hz
kHz
%
V
VDD -0.5V
VDD
V
23
500
26
87.5
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IMP525
Typical Characteristics
Boost Converter
Switching Frequency
EL Lamp Drive Frequency
2400
150
VDD = 1.5V
TA = 25°C
VDD = 1.5V
TA = 25°C
125
Frequency (kHz)
Frequency (Hz)
2000
1600
1200
800
400
100
75
50
25
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
REL (MΩ)
0
4.0
0
0.5
1.5
2.0
2.5
RSW (MΩ)
525_08.eps
3.0
525_10.eps
Boost Converter
Switching Period
EL Lamp Drive Period
8
100
VDD = 1.5V
TA = 25°C
VDD = 1.5V
TA = 25°C
7
6
75
5
Period (ms)
Period (ms)
1.0
4
3
2
50
25
1
0
0
0
0.5
1.0
1.5
2.0
2.5
REL (MΩ)
© Daily Silver IMP
3.0
3.5
4.0
525_07.eps
0
0.5
1.0
1.5
2.0
RSW (MΩ)
Electroluminescent Lamp Driver
2.5
3.0
525_09.eps
3
IMP525
Pin Descriptions
Pin Number
Name
1
VDD
2
RSW-OSC
3
CS
Boost converter storage capacitor. The voltage across the EL lamp is equal to twice the
voltage at CS.
4
LX
Connection to flyback inductance, L.
5
GND
6
VB
EL lamp drive. The lamp is connected to a high-voltage bridge circuit with VB providing
the complementary connection to VA.
EL lamp drive. (See above)
7
VA
8
REL-OSC
Disable Pad
DIS
Function
Positive voltage supply for the IMP525. Inductor L may be connected here or to a
separate supply.
Switch-mode resistor pin. Switching frequency is determined by external resistor RSW,
connected between pin 2 and VDD.
Ground pin.
The EL lamp oscillator frequency-setting pin. The frequency is controlled by resistor REL,
connected from pin 8 to VDD.
Available only in die form. Setting DIS HIGH disables the chip.
External Components
External Component
Diode
Description and Selection Guide
A fast reverse recovery diode, with BV > 100, such as a 1N4148.
Capacitor CS
The high voltage capacitor that stores the inductive energy transferred through the
catch diode. A 100 volt capacitor between 10nF and 100nF is recommended.
Resistor R EL
The EL lamp oscillator frequency-setting resistor. REL is connected between pin 8 and VDD,
providing a frequency inversely proportional to REL; as REL increases, the EL lamp frequency
decreases along with the current drawn by the lamp. Lamp color is also determined by this
frequency. A 1MΩ resistor between the REL-OSC pin and the VDD supply results in a lamp
frequency around 500Hz.
Resistor RSW
Switching Oscillator frequency-setting resistor. RSW is connected between the RSW-OSC pin and
the VDD supply. The switching frequency is inversely proportional to the resistor value, dropping
as the resistance increases.
Capacitor CSW
This is an optional noise-suppression capacitor connected from ground to the RSW-OSC pin.
A 100pF capacitor is recommended.
Inductor L
The inductor provides the voltage boost needed by means of inductive “flyback”. The internal
MOSFET switch alternately opens and closes the ground connection for the inductor at the
LX pin. When the switch opens, the inductor potential will forward-bias the diode
and the current will pass through to the storage capacitor CS, charging it to a high voltage.
As the value of the inductor is increased, the switching frequency set by RSW should also be
increased to prevent saturation. In general, smaller value inductors that can handle more current
are more desirable when larger-area EL lamps must be driven.
A small electrolytic capacitor (10µF, 16V), normally present across the inductor supply VIN,
will likely eliminate the need for CSW.
4
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IMP525
Application Information
Test Circuit
Figure 1 shows the IMP525 configured to drive an EL lamp,
represented as a 3nF capacitor.
ON = VDD
REL
OFF = 0V
1 VDD
REL-OSC
8
2 RSW-OSC
VA
7
3 CS
VB
6
4 LX
GND
5
RSW
L
3nF
D
1N4148
+
VDD
–
0.1µF1
CS
0.1µF
100V
CSW*
0.1nF
IMP525
Note:
1. Larger values may be required depending upon supply impedance.
525_03.eps
* Optional
Figure 1. Test Circuit
Table 1. VIN = 1.5V
Component
Connections
Value
RSW
VDD, RSW-OSC
1MΩ
Description
REL
VDD, REL-OSC
1MΩ
L
VDD, LX2
330µH
CS
CS, GND
0.1µF/100V
D
LX, CS
1N4148
CSW
RSW-OSC, GND
0.1nF
Noise-suppression capacitor
Description
Boost converter oscillator bias resistor
EL lamp driver oscillator bias resistor
2
Boost converter inductor
Boost converter storage capacitor
Switching diode
Notes. 2. Murata LQH4N331K04 (8.2Ω max. DCR)
Table 2. VIN = 0.9V
Component
Connections
Value
RSW
VDD, RSW-OSC
1.0MΩ
Boost converter oscillator bias resistor
REL
VDD, REL-OSC
2.62MΩ
EL lamp driver oscillator bias resistor
L
VDD, LX3
680µH3
Boost converter inductor
CS
CS, GND
0.1µF/100V
D
LX, CS
1N4148
CSW
RSW-OSC, GND
0.1nF
Boost converter storage capacitor
Switching diode
Noise-suppression capacitor
Notes. 3. Coilcraft DS1608C-684 (2.2Ω max. DCR)
© Daily Silver IMP
Electroluminescent Lamp Driver
5
IMP525
Enable/Disable Operation
Figure 2 shows how the IMP525 can be enabled via a logic gate that
connects RSW to VDD, and disabled by connecting it to ground.
Enable/Disable Table
RSW Connection
The IMP525 can also be disabled using a pad on the die. The
Disable function pin is not available in packaged parts.
IMP525 State
Disable PAD Connection
(Available only with dice)
IMP525 State
Enabled
Disabled
HIGH (VDD)
LOW (Ground)
Disabled
Enabled
VDD
Ground
CMOS
Gate
ON = VDD
REL
OFF = 0V
1 VDD
REL-OSC
8
2 RSW-OSC
VA
7
3 CS
VB
6
4 LX
GND
5
RSW
L1
EL lamp
D
1N4148
+
VDD
–
0.1µF2
CS
0.1µF
100V
CSW*
0.1nF
IMP525
Note:
1. Murata part # LQH4N331K04 (DC resistance < 8.2 Ω)
2. Larger values may be required depending upon supply impedance.
* Optional
525_04.eps
Figure 2. Enable/Disable Operation
High Voltages Present
The IMP525 generates high voltages and caution should
be exercised.
Inductor Manufacturers
Manufacturer
Toko
Coilcraft
River Electronics
Murata
6
Series
USA Phone Number
D52FU
(847) 297-0070
DS1608, DO1608, DT1608
(847) 639-6400
FLC32
(310) 320-7488
LQH4N
(800) 831-9172
© Daily Silver IMP
www.ds-imp.com.cn
IMP525
Package Dimensions
MicroSO (8-Pin)
a
Inches
Min
+
E1 E
L
D
C
A2
D
A
e
b
0.10mm
0.004in
Millimeters
Max
Min
Max
MicroSO (8-Pin)
A
–––––
0.0433
––––
1.10
A1
0.0020
0.0059
0.050
0.15
A2
0.0295
0.0374
0.75
0.95
b
0.0098
0.0157
0.25
0.40
C
0.0051
0.0091
0.13
0.23
D
0.1142
0.1220
2.90
3.10
e
0.0256 BSC
E
0.193 BSC
0.65 BSC
4.90 BSC
E1
0.1142
0.1220
2.90
3.10
L
0.0157
0.0276
0.40
0.70
a
0°
6°
0°
6°
SO (8-Pin)
MicroSO (8-Pin).eps
A1
A
0.053
0.069
1.35
1.75
A1
0.004
0.010
0.10
0.25
B
0.013
0.020
0.33
0.51
C
0.007
0.010
0.19
e
SO (8-Pin)
0°– 8°
0.050
0.25
1.27
E
0.150
0.157
3.80
4.00
H
0.228
0.244
5.80
6.20
L
0.016
0.050
0.40
1.27
D
0.189
0.197
4.80
5.00
L
N
E
H
C
D
A
e
B
© Daily Silver IMP
A1
SO (8-Pin).eps
Electroluminescent Lamp Driver
7
IMP525
Daily Silver IMP Microelectronics Co.,Ltd
7 keda Road , Hi-Tech Park,
NingBo,Zhejiang, P.R.C.
Post Code : 315040
Tel:(086)-574-87906358
Fax:(086)-574-87908866
e-mail:[email protected]
Website:www.ds-imp.com.cn
The IMP logo is a registered trademark of Daily Silver IMP.
All other company and product names are trademarks of their respective owners.
2005 Daily Silver IMP
Revision : A
Issue Date: 08/08/05
Type: Product