HVLED807PFTR datasheet(29/36 Pages) STMICROELECTRONICS

Teilenummer	HVLED807PFTR

Bauteilbeschribung	Offline LED driver with primary-sensing and high power factor up to 7 W

PDF	36 Pages

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Hersteller	STMICROELECTRONICS [STMicroelectronics]

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29 / 36 page

HVLED807PF

Device description

Doc ID 023464 Rev 5

29/36

Equation 18

Where VOS_TYP is the desired voltage across COS capacitor applying the VIN_TYP typical

input voltage (i.e. VIN_TYP=220 V for 176/264 Vac input range); Fsw is the switching

frequency and can be estimated using the following formula, where fT and fR are the

transition and resonant frequency respectively:

Equation 19

Equation 20

Equation 21

where CD is the total equivalent capacitor afferent at the drain node.

Based on the desired voltage across COS capacitor and calculated ROS resistor, then the

sum of RA and RB can then calculated as a results of partitioning divider:

Equation 22

Using the previous ROS resistor value the RPF resistor can be estimated using the following

formula:

Equation 23

Finally the current sense resistor RSENSE can be estimated in order to select the

desiderated average output current value:

HVLED807PFTR Datenblatt(PDF) 29 Page - STMicroelectronics