MAX14521E
Quad, High-Voltage EL Lamp Driver
with I
2
C Interface
8 _______________________________________________________________________________________
Detailed Description
The MAX14521E is a quad-output high-voltage DC-AC
converter that drives four EL lamps. The device fea-
tures a 2.7V to 5.5V input range that allows the device
to accept a variety of sources such as single-cell Li+
batteries. The lamp outputs of the device generate up
to 300V
P-P
for maximum lamp brightness.
The MAX14521E utilizes a high-frequency spread-
spectrum boost converter that reduces the amount of
EMI/EFI generated by the circuit. The boost-converter
switching frequency is set with an 8-bit register through
the I
2
C interface. The MAX14521E uses a high-voltage
full-bridge output stage to convert the high voltage gen-
erated by the boost converter to an AC waveform suit-
able for driving an EL lamp. An internal register
controlled through the I
2
C interface sets the shape of
the EL output waveshape.
The EL output switching frequency for all outputs is set
with an 8-bit register through the I
2
C interface. The
MAX14521E provides a serial digital interface that
allows the user to set the peak voltage of each output
independently with 5 bits of resolution. The MAX14521E
also provides an adjustable automatic ramping feature
that slowly increases or decreases the peak output volt-
age when the set value is changed. The slew rate of the
ramp is set with 3 bits of resolution through the I
2
C
interface and it is independent for each channel. The
MAX14521E features an audio auxiliary input AUX that
modulates the EL output voltage and frequency for
dynamic lighting effects.
The high-voltage outputs are ESD protected up to
±15kV Human Body Model, ±8kV Air Gap Discharge,
and ±6kV Contact Discharge, as specified in
IEC 61000-4-2.
Pin Description
PIN NAME FUNCTION
1 EL1 High-Voltage EL Panel Output 1. Connect EL1 to segment 1 of the EL lamp.
2, 4, 16, 18,
20, 22, 24
N.C. No Connection. Not internally connected.
3CSFeed b ack C onnecti on. C onnect C S to the outp ut of the b oost conver ter ( cathod e of the r ecti fyi ng d i od e) .
5 LX Internal Switching DMOS Drain Connection. Connect LX to the middle terminal of the tapped inductor.
6 PGND Power Ground. Connect to GND.
7A0
Address Input 0. Address inputs allow up to four connections on one common bus. Connect A0 to
GND or V
DD
.
8A1
Address Input 1. Address inputs allow up to four connections on one common bus. Connect A1 to
GND or V
DD
.
9V
DD
Input Supply Voltage
10 SDA Open-Drain, Serial Data Input/Output. SDA requires an external pullup resistor.
11 SCL Serial-Clock Input. SCL requires an external pullup resistor.
12 RB
Reset Input. Drive RB low to clear all registers to zero and put the device into a low-power shutdown
mode. The device does not respond to I
2
C communications when RB is held low.
13 AUX Aud i o E ffects Inp ut. M od ul ates am p l i tud e/fr eq uency of the E L outp ut w i th the AU X i np ut vol tag e am p l i tud e.
14 I.C. Internally Connected. Connect I.C. to GND.
15 GND Ground
17 EL4 High-Voltage EL Panel Output 4. Connect EL4 to segment 4 of the EL lamp.
19 EL3 High-Voltage EL Panel Output 3. Connect EL3 to segment 3 of the EL lamp.
21 COM High-Voltage COM Output. Connect COM to common terminal of the EL lamp.
23 EL2 High-Voltage EL Panel Output 2. Connect EL2 to segment 2 of the EL lamp.
— EP Exposed Pad. Connect EP to GND.
