LV5028TT

No.A1999-8/16

Given that the ratio of inductor current to AC input is DutyAC.

DutyAC =

90 - arcsin (

V

ƒ

√2Vrms)

90

Since the period when the inductor current flows are limited by DutyAC, the formula (6) is represented as follows:

L =

V

ƒ

2

× ILED ×

1

ƒosc ×

Vac - V

ƒ

VIN

90 - arcsin (

V

ƒ

√2Vrms)

90

(7)

2

√2

VF

Vac

(AC voltage, R.M.S)

Inductor current

Arcsin (Vf/

√2Vrms)

Arcsin (

√2Vrms/√2Vrms)

=90 (Deg)

Arcsin (Vf/

√2Vrms)