LT3595
APPLICATIONS INFORMATION
Dimming Control
of a channel is 2μs and the maximum period is 10ms (at
100Hz).Therefore,themaximumdimmingratiois5000:1.
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 specific
channel turns on. LED current flows 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
Since the maximum R produces 10mA, the minimum
SET
modulated LED current is 2μA.
When multiple channels are modulated, the rising edges
ofPWM1-16mustbesynchronized.Thefallingedgesmay
be asynchronous. A sample timing diagram is shown in
Figure 3.
SYNCHRONIZED RISING EDGES
PWM1-4
t
= 2μs
ON(MIN)
PWM5-8
t
= 10ms
MAX
PWM9-16
I
LED1-4
LED5-8
I
3595 F03
I
LED9-16
Figure 3. Timing Diagram for Multi-Channel Modulation
3595f
11
Linear [ Linear ]
