Datasheet IMP525EMA Datasheet (IMP)

IMP525

POWER MANAGEMENT

Sing

le Cell Batt

er

y P

y Pooww

er

ed

Electr

oluminescent Lam

oluminescent Lampp

Dr

Driviv

er/In

er/Invv

er

ertt

er

◆ Audio/TV remote control units

◆ Pagers/Cellular phones

◆ PDAs

◆ Clocks and radios

◆ Portable GPS receivers

◆ LCD modules

◆ Toys

◆ 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 converter frequency minimizes circuit power consumption

◆ Disable mode extends battery life

◆ Disable current 1µA typical

◆ Compact MicroSO package option

Block Diagram

–

+

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

V

REF

Lamp Drive

Oscillator

C

GND

5

R

EL-OSC

8

Q

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.

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 1µA typical with a V

DD

of 1.5V. The chip

can be disabled by connecting R

SW

, 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.

Key Features

Applications

IMP525



Parameter Symbol Conditions Min Typ Max Units

ON-resistance of MOS Switch R

DS(ON)

I = 50mA 15 Ω

Operating Voltage 0.9 2.5 V Output Voltage at C

S

V

CS

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

Output Voltage at C

S

V

CS

VDD= 0.9V, See Figure 1, Table 2 50 V

Output Voltage Peak-to-Peak VA-V

B

V

DD

= 1.5V, See Figure 1 104 112 124 V

P-P

Quiescent VDDSupply Current, Disabled I

QDIS

Disable = HIGH 70 nA

(Disable pin available on die only) Quiescent V

DD

Supply Current, Disabled I

QDIS

R

SW-OSC

= GND 1.0 2.0 µA

VDD= 1.5V

Input Current at VDDPin I

DD

VDD= 0.9V to 1.5V 1.5 mA

Input Current: IDDPlus Inductor Current I

IN

VDD= 1.5V 23 32 mA

V

A-B

Output Drive Frequency f

EL

VDD= 1.5V, See Figure 1, Table 1 500 Hz

Boost Converter Switching Frequency f

SW

VDD= 1.5V, See Figure 1, Table 1 26 kHz

Switching Duty Cycle D

SW

VDD= 1.5V, See Figure 1 87.5 %

Disable Input LOW Voltage V

DISL

GND 0.2 V

(Disable pin available on die only) Disable Input HIGH Voltage V

DISH

VDD-0.5V V

DD

V

(Disable pin available on die only)

Ordering Information

Pin Configuration

4L

X

3C

S

2R

SW-OSC

1V

DD

5 GND

6V

B

7V

A

8R

EL-OSC

525_02.eps

IMP525

SO/MicroSO

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

IMP525/D1** 0.9V to 2.5V YES 25°C Dice

Absolute Maximum Ratings

Supply Voltage, VDD, V

RSW-OSC

and V

REL-OSC

. . – 0.5V to +3.5V

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

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

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

Unless otherwise noted, V

DD

= 1.5V, RSW= 1MΩ, REL= 1.0MΩ, and TA= 25°C.

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

* Disable pad not active

** Disable pad active

Add /T to ordering part number for Tape and Reel.

IMP525

Electroluminescent Lamp Driver

9

Typical Characteristics

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



Pin Descriptions

Pin Number Name Function

1V

DD

Positive voltage supply for the IMP525. Inductor L may be connected here or to a separate supply.

2R

SW-OSC

Switch-mode resistor pin. Switching frequency is determined by external resistor RSW, connected between pin 2 and VDD.

3C

S

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

4L

X

Connection to flyback inductance, L.

5 GND Ground pin.

6V

B

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

7V

A

EL lamp drive. (See above)

8R

EL-OSC

The EL lamp oscillator frequency-setting pin. The frequency is controlled by resistor REL, connected from pin 8 to VDD.

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

External Component Description and Selection Guide

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

Capacitor C

S

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. 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

EL-OSC

pin and the VDDsupply results in a lamp

frequency around 500Hz.

Resistor R

SW

Switching Oscillator frequency-setting resistor. RSWis connected between the R

SW-OSC

pin and

the V

DD

supply. The switching frequency is inversely proportional to the resistor value, dropping

as the resistance increases.

Capacitor C

SW

This is an optional noise-suppression capacitor connected from ground to the R

SW-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 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.

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

SW

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.

External Components

IMP525

Electroluminescent Lamp Driver

11

+

–

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.

* Optional

525_03.eps

0.1µF 100V

CSW*

0.1nF

ON = V

DD

OFF = 0V

Figure 1. Test Circuit

Test Circuit

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

represented as a 3nF capacitor.

Application Information

Component Connections Value Description

R

SW

VDD, R

SW-OSC

1MΩ Boost converter oscillator bias resistor

R

EL

VDD, R

EL-OSC

1MΩ EL lamp driver oscillator bias resistor

LV

DD

, L

X

2

330µH

2

Boost converter inductor

C

S

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

DL

X

, C

S

1N4148 Switching diode

C

SW

R

SW-OSC

, GND 0.1nF Noise-suppression capacitor

Table 1. VIN= 1.5V

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

Component Connections Value Description

R

SW

VDD, R

SW-OSC

1.0MΩ Boost converter oscillator bias resistor

R

EL

VDD, R

EL-OSC

2.62MΩ EL lamp driver oscillator bias resistor

LV

DD

, L

X

3

680µH

3

Boost converter inductor

C

S

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

DL

X

, C

S

1N4148 Switching diode

C

SW

R

SW-OSC

, GND 0.1nF Noise-suppression capacitor

Table 2. VIN= 0.9V

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

IMP525



Enable/Disable Operation

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

SW

to VDD, and disabled by connecting it to ground.

RSWConnection IMP525 State

V

DD

Enabled

Ground Disabled

Figure 2. Enable/Disable Operation

Enable/Disable Table

Disable PAD Connection

(Available only with dice) IMP525 State

HIGH (VDD) Disabled

LOW (Ground) Enabled

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

+

–

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

1N4148

EL lamp

Note:

1. Murata part # LQH4N331K04 (DC resistance < 8.2

Ω

)

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

* Optional

525_04.eps

ON = V

DD

OFF = 0V

0.1µF 100V

C

SW

*

0.1nF

C

S

D

High Voltages Present

The IMP525 generates high voltages and caution should be exercised.

Manufacturer Series USA Phone Number

Toko D52FU (847) 297-0070

Coilcraft DS1608, DO1608, DT1608 (847) 639-6400

River Electronics FLC32 (310) 320-7488

Murata LQH4N (800) 831-9172

Inductor Manufacturers

IMP525

Electroluminescent Lamp Driver

13

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

a0° 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

SO (8-Pin)

Package Dimensions

MicroSO (8-Pin)

a

E1 E

+

L

D

A2

A

0.10mm

D

e

b

0.004in

A1

C

MicroSO (8-Pin).eps

0°– 8°

N

L

H

E

D

A

e

B

A1

C

SO (8-Pin).eps

IMP, Inc. Corporate Headquarters 2830 N. First Street San Jose, CA 95134-2071 Tel: 408-432-9100 Fax: 408-434-0335 e-mail: [email protected] 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.

©

2000 IMP, Inc. Printed in USA Publication #: 2002 Revision: B Issue Date: 07/11/00 Type: Product

IMP525