HVLED001BTR datasheet(21/33 Pages) STMICROELECTRONICS

Part #	HVLED001BTR

Description	High power factor flyback controller with constant voltage primary-sensing and ultra-low standby consumption

PDF	33 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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21 / 33 page

DS12748 Rev 2

21/33

HVLED001B

Application information

Figure 20. Control loop blocks

7.2.1

Current sense input

The peak of the primary current is read across a shunt resistor placed between the

MOSFET‘s source and compared with a threshold equal to:

Equation 1

Where the term VHVSU,pk is the maximum value of the HVSU voltage within around 20 ms

and is used to compensate the dependency on the input voltage of the open loop gain

transfer function. The gain kp collects all the proportional terms between HVSU voltage and

CS threshold.

A leading edge blanking time (LEB) is applied after MOSFET‘s turn-on.

VCS signal is upper limited to a value that depends on the OPTO voltage and is lower

limited to 60 mV.

A second level OCP threshold is present to temporarily stop the switching activity in case of

inductor saturation.

HVLED001BTR Datasheet(PDF) 21 Page - STMicroelectronics