IMP522 IMP Inc, IMP522 Datasheet - Page 5

• Manufacturer Part Number: IMP522
• Description: Dual EL Lamp Driver
• Manufacturer: IMP Inc

Power Sequencing
To power up the chip, the R
the external R
V
voltage and when it exceeds the threshold range (0.2V to 0.9V) it
powers up the oscillator and internal bias modules. This starts a
delay counter which is one half of the EL oscillator period, after
which power to the high voltage internal modules is applied. The
IMP522 is then operating fully.
To power down the chip, R
logic gate. When the voltage on the driver side of the resistor falls
below V
pin. This immediately powers down the internal high-voltage
circuits, which effectively shuts the lamp off. At this point the
oscillator and bias modules still draw quiescent current, but oscil-
lations have ceased. As the R
oscillator and bias modules are also fully powered down.
© 2001 IMP, Inc.
IN (Pulse)
DD
/2. An internal threshold detector circuit monitors the pin
I
V
LX
DD
LX
/2, there will be no input bias current into the R
SW
resistor. The voltage on the pin will charge up to
Figure 1. Driver Waveforms
SW-OSC
SW
SW-OSC
is driven to ground via a switch or
pin is connected to V
pin voltage falls below 0.1, the
DD
522_03.eps
through
SW-OSC
Power Saving Disable Mode
The IMP522 can be powered up and down with R
normal operation, this resistor on the R
V
IMP522, R
When disabled, the IMP522 quiescent current drops to typically 20nA.
In die form, an extra pin ENABLE is available (contact factory).
Connecting this pad to V
can be driven by a microcontroller.
Oscillator Frequency Adjustment
The EL lamp drive and PWM boost converter oscillation frequen-
cies can be programmed independently.
The R
determines the Inductor Switching (or PWM-) frequency. For the
recommended nominal resistor value of 910kΩ, the frequency is
61kHz. For other resistor values, the frequency is inversely pro-
portional to the resistor value. Increasing the resistance will lower
the frequency.
The R
determines the EL lamp drive frequency. For the recommended
nominal resistor value of 2.7MΩ, the frequency is 250Hz. For
other resistor values, the frequency is inversely proportional to
the resistor value: increasing the resistance will lower the fre-
quency.
n I
DD
d
u
or another voltage source. To power down (disable) the
E
t c
SW
EL
O
L
r o
L
s
resistor, connected between the R
resistor, connected between the R
a
Electroluminescent Lamp Drivers
l i c
S
SW
m
w
t a l
p
c t i
is connected to ground.
D
h
r o
r
v i
P (
e
W
M
)
DD
disables the chip. The ENABLE signal
Application Information
R
R
N
R
S
E
W
L
o
s e
=
m
=
t s i
2
9
n i
7 .
1
r o
0
M
l a
k
Ω
Ω
SW-OSC
I M P 5 2 2
I M P 5 2 2
SW-OSC
EL-OSC
pin is connected to
F
N
e r
o
2
6
pin and V
u q
pin and V
5
1
m
0
k
H
H
n i
n e
SW-OSC
z
z
l a
y c
5
2
2
_
0 t
3
e .
. In
p
DD
DD
s
5
,
,