irs2548d International Rectifier Corp., irs2548d Datasheet - Page 18

• Manufacturer Part Number: irs2548d
• Description: Smps/led Driver Pfc + Half-bridge Control Ic
• Manufacturer: International Rectifier Corp.

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IV. PFC Design Equations
Step1: Calculate PFC inductor value:
Step 2: Calculate peak PFC inductor current:
Step 3: Calculate PFC over-current resistor ROC value:
i
R
where,
Note: The PFC inductor must not saturate at
range. Proper core sizing and air-gapping should be considered in the inductor design.
VBUS
VAC
η
L
P
PK
f
OC
OUT
MIN
PFC
=
=
MIN
=
. 1
2
i
VAC
PK
25
⋅
(
VBUS
= Minimum rms AC input voltage
2
= DC bus voltage
= PFC efficiency (typically 0.95)
= Minimum PFC switching frequency at minimum AC input voltage
= System output power
MIN
⋅
P
where VCSTH+ = 1.25V
OUT
2
⋅
−
η
⋅
f
MIN
2
⋅
VAC
⋅
P
OUT
MIN
⋅
VBUS
)
⋅
VAC
MIN
2
⋅
η
18
i
PK
over the specified system operating temperature
[Henries]
[Amps Peak]
[Ohms]
© 2011 International Rectifier
IRS2548D