IMP527D1 Ver la hoja de datos (PDF) - IMP, Inc

Número de pieza

componentes Descripción

Fabricante

IMP527D1

Single Cell Battery Powered Electroluminescent Lamp Driver/Inverter

IMP, Inc 

IMP527

Pin Descriptions

Pin Number

1

2

3

4

5

6

7

8

Disable Pad

Name

VDD

RSW-OSC

CS

LX

GND

VB

VA

REL-OSC

DIS

Function

Positive voltage supply for the IMP527. 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.

Ground pin.

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)

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

Capacitor CS

Resistor REL

Resistor RSW

Capacitor CSW

Inductor L

Description and Selection Guide

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

The high voltage capacitor that stores the inductive energy transferred through the

catch diode. A 100 volt capacitor between 10nF and 100nF is recommended.

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.

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.

This is an optional noise-suppression capacitor connected from ground to the RSW-OSC pin.

A 100pF capacitor is recommended.

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

408-432-9100/www.impweb.com

© 2000 IMP, Inc.

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