L6911E View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6911E' PDF : 34 Pages View PDF
Device description
L6911E
Considering the previous relationships R2, R3, R8 and R9 may be determined in order to
obtain the desired droop effect as follow:
● Choose a value for R2 in the range of hundreds of KΩ to obtain realistic values for the
other components.
● From the above equations, it results:
Equation 15
R8
=
∆-----V----+----⋅---R-----2-
VPROG
⋅
∆--R--V--L--D--⋅--R-I--M-O---A-O---X-P-
Equation 16
R9
=
R8
⋅
∆----V----D----R----O----O----P-
RL ⋅ IMAX
⋅
-----------------1------------------
1 + ∆--R--V--L--D--⋅--R-I--M-O---A-O---X-P-
Where IMAX is the maximum output current.
● The component R3 must be chosen in order to obtain R3 << R8//R9 to permit these
and successive simplifications.
Therefore, with the droop function the output voltage decreases as the load current
increases, so the DC output impedance is equal to a resistance ROUT. It is easy to verify that
the output voltage deviation under load transient is minimum when the output impedance is
constant with frequency.
20/34
Share Link: 
