DS12748 Rev 2

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HVLED001B

Application information

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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

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

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.