August 2004

7

MIC4826

MIC4826

Micrel

EL Frequency

The EL lamp frequency is controlled via an external resistor

connected between REL pin and VDD pin of the device. As

the lamp frequency increases, the resistor value decreases.

For resistor value selections, see the “Typical

Characteristics: EL Frequency vs. EL Resistor” or use the

equation below. The EL frequency range is 60Hz to 1000Hz,

with an accuracy of

±20%.

fHz

RM

EL

EL

()

()

=

Ω

360

TIME (2ms/div)

V

L = 220

µH

C

R

R

Figure 3. 180Hz Output Waveform

In general, as the EL lamp frequency increases, the amount

of current drawn from the battery will increase. The color of

the EL lamp and the intensity are dependent upon its fre-

quency.

TIME (2ms/div)

V

L = 220

µH

C

R

R

Figure 4. 360Hz Output Waveform

Enable Function

The enable function of the MIC4826 is implemented by

switching the R

When R

the EL oscillators are disabled; therefore the EL driver be-

comes disabled. When these resistors connect to V

oscillators will function and the EL driver is enabled.