MIC4827 Micrel Semiconductor, MIC4827 Datasheet - Page 7

• Manufacturer Part Number: MIC4827
• Description: Low Input Voltage/ 180VPP Output Voltage/ EL Driver
• Manufacturer: Micrel Semiconductor

EL Frequency
The EL lamp frequency is controlled via an external resistor
connected between REL pin and VDD pin of the device. 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
switching frequency range is 60Hz to 1000Hz, with an accu-
racy of 20%.
September 2001
MIC4827
f (Hz)
EL
Figure 3. 180Hz Output Waveform
R (M )
EL
360
TIME (2ms/div)
V
L = 220 H
C
Lamp = 2in
R
R
IN
OUT
SW
EL
= 3.0V
= 1M
= 562k
= 0.033 F
2
7
of current drawn from the battery will increase. The color of
the EL lamp and the intensity are dependent upon its fre-
quency.
Enable Function
The enable function of the MIC4827 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
the oscillators will function and the EL driver is enabled.
In general, as the EL lamp frequency increases, the amount
SW
Figure 4. 360Hz Output Waveform
and R
SW
EL
and R
are connected to ground, the switch and
EL
resistor between ground and V
TIME (2ms/div)
MIC4827
DD
Micrel
, both
DD
.