lx1996 Microsemi Corporation, lx1996 Datasheet - Page 14

• Manufacturer Part Number: lx1996
• Description: Multi-string Led Back-light Controller
• Manufacturer: Microsemi Corporation

Copyright © 2007
Rev. 1.0, 2007-12-14
Direct Analog Dimming with Ultra Sonic Pulse Skipping
Freq. Range
Freq. Range
Freq. Range
Freq. Range
100Hz
25kHz
100Hz
25kHz
PWM
PWM
DIGITAL DIMMING MODES OF OPERATION
ANALOG DIMMING MODES OF OPERATION
N/A
N/A
to
to
TM
Combined Analog and Digital Dimming
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Direct Analog Dimming
Direct Digital Dimming
Enables USPS in analog dimming
mode to reduce boost inductor noise
by moving the switching frequency
out of the audible range.
LED current will be turned On/Off
directly by PWM.
The maximum LED current is set by a
programmable resistor.
Dimming ratio is 10:1 at internal
frequency = 25kHz. It will be
proportionally higher at lower
frequency. The minimum pulse width
is 4μsec
Signal into DI pin will be either from
an Ambient Light Sensor (ALS) or a
variable voltage source, V
The LED current is linearly controlled
by a programmable resistor and V
Valid V
LED current will be turned On/Off
directly by PWM.
Dimming ratio is 100:1 at PWM =
25kHz. It will be proportionally
higher at lower frequency. The
minimum pulse width is 4μsec
Signal into DI pin will be either from
Ambient Light Sensor (ALS) or the
adjustable voltage source, V
The LED current is linearly
controlled by a programmable
resistor and V
Valid V
The Dimming ratio can go up to 10:1.
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
Controller Performance
Controller Performance
Controller Performance
Controller Performance
(USPS)
DI
DI
range is 0.2V to 2.0V
range is 0.2V to 2.0V
DI
DI
O P E R A T I O N T H E O R Y
Analog Mixed Signal Group
DI
Microsemi
®
DI
Multi-string LED Back-light Controller
Analog to Digital dimming with external synchronization
Freq. Range
Freq. Range
frequency
frequency
100Hz –
100Hz –
Internal
Internal
25kHz
25kHz
P
RODUCTION
Analog to Digital dimming
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PWM duty cycle controlled by the
signal into the DI pin
Signal into DI pin will be either from
an Ambient Light Sensor (ALS) or a
variable voltage source, V
V
2.4V
PWM signal is generated by an
internal oscillator. Dimming
frequency is set by a capacitor
connected to the C
The maximum LED current is set by
a programmable resistor connected to
the RPRG pin.
LED current will be turned On/Off
directly by the internal PWM
The internal PWM synchronizes to a
clock on the PWM input pin
Dimming ratio is 10:1 at internal
frequency = 25kHz. It will be
proportionally higher at lower
frequency. The minimum pulse
width is 4μsec
PWM duty cycle controlled by the
signal into the DI pin
Signal into DI pin will be either from
an Ambient Light Sensor (ALS) or a
variable voltage source, V
V
2.4V
PWM signal is generated by an
internal oscillator. Dimming
frequency is set by a capacitor
connected to the C
The maximum LED current is set by
a programmable resistor connected to
the RPRG pin.
LED current will be turned On/Off
directly by the internal PWM.
Dimming ratio is 10:1 at internal
frequency = 25kHz. It will be
proportionally higher at lower
frequency. The minimum pulse
width is 4μsec
DI
DI
will be in the range of 0.4V to
will be in the range of 0.4V to
Controller Performance
Controller Performance
clock
D
ATASHEET
T
T
pin
pin
DI
LX1996
DI
Page 14