TN0026

Equations (see Figure 3)

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Figure 3.

LED balancing circuit - multiple strings

2

Equations (see Figure 3)

2.1

emitter resistor

Equation 1

Equation 2

2.2

Operation of LED balancing circuits for one open LED

Equation 3

Equation 4

Equation 5

I

Re

V

–

R

e

--------------------

=

Re

V

r

V

be

–

()

I

R

e

--------------------------

=

I

Rr

V

in

V

r

–

()

R

r

------------------------

=

I

Re

V

r

V

be

min

–

()

R

e

--------------------------------

=

V

r

V

be

max

I

Rr

R

e

•

+

=