lt3595a Linear Technology Corporation, lt3595a Datasheet - Page 11

• Manufacturer Part Number: lt3595a
• Description: 16 Channel Buck Mode Led Driver
• Manufacturer: Linear Technology Corporation

APPLICATIONS INFORMATION
Dimming Control
The sixteen PWM1-16 inputs control the dimming func-
tion. Each channel is modulated by its corresponding
PWM1-16 input. On a rising edge of any PWM1-16, the
IC’s internal support circuitry is enabled and the specifi c
channel turns on. LED current fl ows in the channel until
the falling edge of the PWM1-16 input. In this way, the
average LED current is modulated. The minimum on time
PWM9-16
PWM1-4
PWM5-8
I
LED9-16
I
I
LED1-4
LED5-8
t
ON(MIN)
Figure 3. Timing Diagram for Multi-Channel Modulation
SYNCHRONIZED RISING EDGES
t
MAX
= 2μs
= 10ms
of a channel is 2μs and the maximum period is 10ms (at
100Hz). Therefore, the maximum dimming ratio is 5000:1.
Since the maximum R
modulated LED current is 2μA.
When multiple channels are modulated, the rising edges
of PWM1-16 must be synchronized. The falling edges may
be asynchronous. A sample timing diagram is shown in
Figure 3.
SET
produces 10mA, the minimum
3595A F03
LT3595A
11
3595af