MAX1996AETI+ Maxim Integrated Products, MAX1996AETI+ Datasheet - Page 16

• Manufacturer Part Number: MAX1996AETI+
• Description: Display Drivers CCFL Backlight Controller
• Manufacturer: Maxim Integrated Products

Specifications of MAX1996AETI+

• Lead Free Status / Rohs Status: Details

Figure 9. Useful Dimming Range
a 500pF capacitor from an AC signal source to MODE as
shown in Figure 10. The amplitude of the AC signal must
be at least 2V
operation. The transition time of the AC signal should be
less than 200µs. The synchronization range is 32kHz to
100kHz, which corresponds to a DPWM frequency range
of 250Hz to 781Hz (128 MODE pulses per DPWM cycle).
High DPWM frequencies limit the dimming range. See the
Loop Compensation section for more information con-
cerning high DPWM frequencies.
A simple oscillator circuit as shown in Figure 11 can be
used to generate the synchronization signal. The core of
the oscillator is the MAX9031, which is a low-cost, single-
High-Efficiency, Wide Brightness
Range, CCFL Backlight Controller
16
______________________________________________________________________________________
CONVENTIONAL INTERFACE
P-P
but no greater than 5V
CONTROL VOLTAGE
CONTROL VOLTAGE
CONTROL VOLTAGE
CONTROL VOLTAGE
INTERFACE
MAX BRIGHTNESS
MAX BRIGHTNESS
MAX1996A
MIN BRIGHTNESS
MIN BRIGHTNESS
P-P
for accurate
TOLERANCE
TOLERANCE
supply comparator in a 5-pin SC70 package. The V
and REF of the MAX1996A provide the supply voltage
and the reference voltage for the oscillator. The positive
threshold of the oscillator is: V
negative threshold is given by: V
quency of the oscillator is:
For C = 330pF and R = 13kΩ, the resulting oscillator fre-
quency is 100kHz. For C = 330pF and R = 39kΩ, the
oscillator frequency is 32kHz.
GND
GND
TYPICAL DIMMING RANGE
f
=
RC
ln
MAX BRIGHTNESS
INPUT VOLTAGE
TYPICAL DIMMING
RANGE
TYPICAL DIMMING
RANGE LOST
MIN BRIGHTNESS
INPUT VOLTAGE
MAX BRIGHTNESS
INPUT VOLTAGE
MIN BRIGHTNESS
INPUT VOLTAGE
V
V
TH
TH
+
−
(
(
1
V
V
CC
CC
TH+
−
−
V
V
TH
TH
TH-
= (V
−
+
)
)
= V
CC
REF
+ V
/2. The fre-
REF
)/2. The
CC