HV825LG-G 데이터 시트보기 (PDF) - Supertex Inc

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HV825LG-G

High Voltage EL Lamp Driver IC

Supertex Inc 

Test Circuit

Enable

ON = VDD

OFF = GND

1MΩ

VDD = VIN = 1.0V - 1.6V

560µH1

750KΩ

1 VDD REL-Osc 8

2 RSW-Osc

VA 7

0.1µF

1N4148

0.01µF

100V

3 CS

VB 6

4 LX

GND 5

HV825LG or

CSW

1nF

HV825MG

2.2KΩ

4.7nF

Equivalent to

1.5in2 lamp

HV825

Typical Performance

Lamp Size

1.5in2

V

IN

1.5V

I

DD

30mA

V

CS

56V

Notes: 1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)

f

EL

450Hz

Brightness

3.65ft-lm

External Component Description

External

Component

Diode

Selection Guide Line

Fast reverse recovery, 1N4148 or equivalent.

C Capacitor

S

REL-Osc Resistor

0.01 to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor.

The lamp frequency is controlled via the REL-Osc. The lamp frequency increases as the REL-Osc decreases.

As the lamp frequency increases, the amount of current drawn from the battery will increase and the

output voltage VCS will decrease. This is because the lamp will draw more current from VCS when

driven at higher frequencies.

RSW-Osc Resistor

LX Inductor

In general, as the lamp size increases, a larger REL-Osc is recommended to provide higher VCS. However,

the color of the lamp is dependent upon its frequency and the shade of the color will change slightly

with different frequencies.

The switching frequency of the inductor is controlled via the RSW-Osc. The switching frequency increases

as the RSW-Osc decreases. As the switching frequency increases, the amount of current drawn from the

battery will decrease and the output voltage VCS will also decrease.

The inductor LX is used to boost up the low input voltage. When the internal switch is on, the inductor

is being charged. When the internal switch is off, the charge in the inductor will be transferred to the

high voltage capacitor CS. The energy stored in the capacitor is connected to the internal H-bridge and

therefore to the lamp. In general smaller value inductors, which can handle more current, are more

suitable to drive larger size lamps. As the inductor value decreases, the switching frequency of the

inductor (controlled by R ) should be increased to avoid saturation.

SW-Osc

The test circuit uses a Murata (LQH4N561) 560µH inductor. Using different inductor values or induc-

tors from different manufacturers will affect the performance.

CSW Capacitor

As the inductor value decreases, smaller RSW-Osc values should be used. This will prevent inductor

saturation. An inductor with the same inductance value, (560µH), but lower series resistance, will

charge faster.

The RSW-Osc resistor value needs to be decreased to prevent inductor saturation and high current

consumption.

A 1nF capacitor is recommended from RSW-Osc pin to GND. This capacitor is used to shunt any

switching noise that may couple into the RSW-Osc pin.

3

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