Datasheet IMP525ESA, IMP525-D Datasheet (IMP)

–

+

525_01.eps

V

DD

1

L

X

4

C

S

3

V

A

7

V

B

6

R

SW-OSC

2

Switch

Oscillator

Regulation

Control

IMP525

Bridge
Output

Driver

Q

Q

Q

V

REF

Lamp Drive

Oscillator

C

GND

5

R

EL-OSC

8

Q

POWER MANAGEMENT

IMP525

IMP525

Sing

Sing

Electr

Electr

Driviv

Dr

The IMP525 is an Electroluminescent (EL) lamp driver designed for sys­tems that must operate below 1 volt. The input supply voltage range is

0.9V to 2.5V. Typical output lamp drive voltage is 112V. All four EL lamp­driving 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 . ELlamps of up to 6nF capacitance can be dri­ven to high brightness.

The circuit requires few external components; one inductor, one diode,
one capacitor and two resistors. The resistors set the frequency for the
two oscillators.

A disable mode puts the chip into a low current-drain state. When dis­abled, quiescent current drops to 2µAmaximum with a V
chip can be disabled by connecting R
resistors, to ground. A disable pad, 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.

le Cell Batterer

le Cell Batt

oluminescent Lampp

oluminescent Lam

er/Invverertterer

er/In

y Poowwerer

y P

, the oscillator frequency setting

SW

ed

ed

of 1.5V. The

DD

Block Diagram

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

◆ Adjustable output frequency controls lamp

color and power consumption

◆ Adjustable conver ter frequency minimizes

circuit power consumption

◆ Disable mode extends batter y life

◆ Disable current under 2

◆ Compact MicroSO package option

µA

Applications

◆ Audio/TV remote control units

◆ Pagers/Cellular phones

◆ PDAs

◆ Clocks and radios

◆ Portable GPS receivers

◆ LCD modules

◆ Toys

IMP, Inc. San Jose, CA 408-432-9100/www.impweb.com

IMP525

4L

X

3C

S

2R

SW-OSC

1V

DD

5 GND

6 V

B

7 V

A

8 R

EL-OSC

525_02.eps

IMP525

IMP525

Pin Configuration

SO/MicroSO

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 0.9V to 2.5V YES –40°C to +85°C 8-SO

IMP525/D 0.9V to 2.5V YES 25°C Dice

Absolute Maximum Ratings

Supply Voltage, VDD, V

RSW-OSC

Storage Temperature Range . . . . . . . . . . . . . . . . – 65°C to +150°C

Power Dissipation (SO package) . . . . . . . . . . . . 400mW

Power Dissipation (MicroSO package) . . . . . . . 300mW

and V

REL-OSC

. . – 0.5V to +3.5V

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, V

Parameter Symbol Conditions Min Typ Max Units

ON-resistance of MOS Switch R
Operating Voltage 0.9 2.5 V
Output Voltage at C
Output Voltage at C
Output Voltage Peak-to-Peak VA-V
Quiescent VDDSupply Current, Disabled I

(Disable pin available on die only)
Quiescent V

Input Current at VDDPin I
Input Current: IDDPlus Inductor Current I
V

Output Drive Frequency f

A-B

Boost Converter Switching Frequency f
Switching Duty Cycle D
Disable Input LOW Voltage V
(Disable pin available on die only)
Disable Input HIGH Voltage V
(Disable pin available on die only)

2

S
S

Supply Current, Disabled I

DD

DD

= 1.5V, R

= 1MΩ, REL= 1.0MΩ, and T

SW

DS(ON)

V

CS

V

CS

QDIS

QDIS

I = 50mA 15 Ω

VDD= 1.5V, See Figure 1, Table 1 52 58 65 V
VDD= 0.9V, See Figure 1, Table 2 50 V
V

B

DD

Disable = HIGH 70 nA

R

SW-OSC

VDD= 1.5V

DD

IN

EL

SW

SW

DISL

DISH

VDD= 0.9V to 1.5V 1.5 mA
VDD= 1.5V 23 32 mA
VDD= 1.5V, See Figure 1, Table 1 500 Hz
VDD= 1.5V, See Figure 1, Table 1 26 kHz
VDD= 1.5V, See Figure 1 87.5 %

= 25°C.

A

= 1.5V, See Figure 1 104 112 124 V

= GND 1.0 2.0 µA

GND 0.2 V

VDD- 0.5V V

DD

P-P

V

IMP525

Frequency (Hz)

REL (MΩ)

EL Lamp Drive Frequency

525_08.eps

VDD= 1.5V

TA= 25°C

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

400

800

1200

1600

2000

2400

Frequency (kHz)

RSW (MΩ)

525_10.eps

0 0.5 1.0 1.5 2.0 2.5 3.0

0

25

50

75

100

125

150

Boost Converter

Switching Frequency

VDD= 1.5V

TA= 25°C

Period (ms)

REL (MΩ)

525_07.eps

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

1

2

3

4

5

6

7

8

EL Lamp Drive Period

VDD= 1.5V

TA= 25°C

Period (ms)

RSW (MΩ)

525_09.eps

0 0.5 1.0 1.5 2.0 2.5 3.0

0

25

50

75

100

Boost Converter

Switching Period

VDD= 1.5V

TA= 25°C

IMP525

Typical Characteristics

3

Pin Descriptions

Pin Number Name Function

1 V

2 R

3 C

4 L

DD

SW-OSC

S

X

5 GND Ground pin.
6 V

7 V
8 R

B

A

EL-OSC

Disable Pad DIS Available only in die form. Setting DIS HIGH disables the chip.

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.

Boost converter storage capacitor. The voltage across the EL lamp is equal to twice the
voltage at CS.

Connection to flyback inductance, L.

EL lamp drive. The lamp is connected to a high-voltage bridge circuit with VBproviding
the complementary connection to VA.

EL lamp drive. (See above)
The EL lamp oscillator frequency-setting pin. The frequency is controlled by resistor REL,

connected from pin 8 to VDD.

IMP525

IMP525

External Components

External Component Description and Selection Guide

Diode Afast reverse recovery diode, with BV > 100, such as a 1N4148.

Capacitor C

Resistor R

Resistor R

Capacitor C

S

EL

SW

SW

Inductor L The inductor provides the voltage boost needed by means of inductive “flyback”. The internal

The high voltage capacitor that stores the inductive energy transferred through the
catch diode. A100 volt capacitor between 10nF and 100nF is recommended.

The EL lamp oscillator frequency-setting resistor. RELis connected between pin 8 and VDD,
providing a frequency inversely proportional to REL; as RELincreases, 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 R
frequency around 500Hz.

Switching Oscillator frequency-setting resistor. RSWis connected between the R
the VDDsupply. The switching frequency is inversely proportional to the resistor value, dropping
as the resistance increases.

This is an optional noise-suppression capacitor connected from ground to the R
A 100pF capacitor is recommended.

MOSFET switch alternately opens and closes the ground connection for the inductor at the
LXpin. 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.

pin and the VDDsupply results in a lamp

EL-OSC

SW-OSC

SW-OSC

pin and

pin.

As the value of the inductor is increased, the switching frequency set by RSWshould 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

+
–

V

DD

R

SW-OSC

C

S

L

X

R

EL-OSC

V

A

V

B

GND

8
7
6
5

1
2
3
4

IMP525

R

EL

R

SW

C

S

V

DD

0.1µF

1

1N4148

D

L

3nF

Note:

1. Larger values may be required depending upon supply impedance.

525_03.eps

0.1µF
100V

ON = V

DD

OFF = 0V

Test Circuit

Figure 1 shows the IMP525 configured to drive an EL lamp,

represented as a 3nF capacitor.

IMP525

IMP525

Application Information

Table 1. VIN= 1.5V

Component Connections Value Description

R

SW

R

EL

L VDD, L

C

S

D LX, C

Notes. 2. Murata LQH4N331K04 (8.2Ωmax. DCR)

Table 2. VIN= 0.9V

Component Connections Value Description

R

Notes. 3. Coilcraft DS1608C-684 (2.2Ωmax. DCR)

SW

R

EL

L VDD, L

C

S

D LX, C

VDD, R

SW-OSC

VDD, R

EL-OSC

X

CS, GND 0.1µF/100V Boost converter storage capacitor

S

VDD, R

SW-OSC

VDD, R

EL-OSC

X

CS, GND 0.1µF/100V Boost converter storage capacitor

S

Figure 1. Test Circuit

2

3

1MΩ Boost converter oscillator bias resistor
1MΩ EL lamp driver oscillator bias resistor

2

330µH

Boost converter inductor

1N4148 Switching diode

1.0MΩ Boost converter oscillator bias resistor

2.62MΩ EL lamp driver oscillator bias resistor

3

680µH

1N4148 Switching diode

Boost converter inductor

5

Enable/Disable Operation

+
–

V

DD

R

SW-OSC

C

S

L

X

R

EL-OSC

V

A

V

B

GND

8
7
6
5

1
2
3
4

IMP525

R

EL

CMOS

Gate

R

SW

L

1

V

DD

0.1µF

2

15V

1N4148

EL lamp

Note:

1. Murata part # LQH4N561K04 (DC resistance <14.5

Ω

)

2. Larger values may be required depending upon supply impedance.

3. Optional noise-suppression capacitor.

0.1nF

3

525_04.eps

ON = V

DD

OFF = 0V

0.1µF
100V

C

S

D

Figure 2 shows how the IMP525 can be enabled via a logic gate that
connects R

to VDD, and disabled by connecting it to ground.

SW

IMP525

IMP525

The IMP525 can also be disabled using a pad on the die. The
Disable function pin is not available in packaged parts.

Enable/Disable Table

RSWConnection IMP525 State

V

DD

Ground Disabled

Enabled

Disable PAD Connection

(Available only with dice) IMP525 State

HIGH (VDD) Disabled

LOW (Ground) Enabled

Figure 2. Enable/Disable Operation

High Voltages Present

The IMP525 generates high voltages and caution should
be exercised.

Inductor Manufacturers

Manufacturer Series USA Phone Number

Toko D52FU [phone]

Coilcraft DS1608, DO1608, DT1608 [phone]

River Electronics FLC32 [phone]

6

IMP525

L

0°– 8°

C

H

E

N

e

D

B

A1

A

SO (8-Pin).eps

e

b

D

E1 E

a

L

+

C

D

0.10mm

0.004in

A1

A2

A

MicroSO (8-Pin).eps

IMP525

MicroSO (8-Pin)

SO (8-Pin)

Package Dimensions

Inches Millimeters

Min 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 0.65 BSC
E 0.193 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)

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 0.25
e 0.050 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

7

IMP525

IMP525

IMP, Inc.
Corporate Headquarters
2830 N. First Street
San Jose, CA 95134-2071
Tel: [phone]
Tel: [phone]
Fax: [phone]
Fax-on-Demand: 1-800-249-1614 (USA)
Fax-on-Demand: 1-303-575-6156 (International)
e-mail: [e-mail]
http://www.impweb.com

The IMP logo is a registered trademark of IMP, Inc.

All other company and product names are trademarks of their respective owners.

8

© 1998 IMP, Inc.
Printed in USA
Part No.: IMP 525
Preliminary
Document Number: IMP525-8-9/98