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L6984

Device description

34

Figure 5. L6984 application circuit

Laplace transformer of the leading network:

Equation 3

where:

Equation 4

Equation 5

3.2

Control loop

The L6984 device is based on a constant on-time control loop with frequency feed-forward

correction over the input range. As a consequence the on-time generator compensates the

input voltage variations in order to keep the switching frequency almost constant over the

input voltage range.



+

--------------------



+



1s



+



+





-----------------------------------------------------------



=

1

2

 R





--------------------------------------

=

1

2





+





---------------------------------------------------

=



28 10

3

–



----------------------------------



=