Analog dimming control

STLD20D

20/31

9

Analog dimming control

Some application are sensitive to low frequency dimming signal; in this case an analog

used with the circuit shown

Figure 22.

Where:

●

●

9.1

Minimum dimming current

This minimum dimming current depends on the maximum input voltage and the forward

voltage of the LED and can be estimated by:

I

LED

V

FB

R

dim

R

d1

R

LED

++

() V

dim

R

LED

R

d1

+

()

⋅

–

⋅

R

dim

R

LED

⋅

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19

[]

=

Figure 22.

Analogical dimming schematics

+

-

PWM

R1

C1

STLD20D

C2

R2

GND

I

LEDC

DC

min

V

IN max

()

⋅

()

2

2L

typ

F

typ

NV

LED

⋅

V

FB

V

IN max

()

–

+

[]

⋅⋅

⋅

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