Datasheet

LM2524D, LM3524D
SNVS766E –JUNE 2009–REVISED MAY 2013 www.ti.com
Figure 26. 5V, 1 Amp Switching Regulator, Foil Side
Figure 27. Stuffing Diagram, Component Side
The Step-Up Switching Regulator
Figure 28 shows the basic circuit for a step-up switching regulator. In this circuit Q1 is used as a switch to
alternately apply V
IN
across inductor L1. During the time, t
ON
, Q1 is ON and energy is drawn from V
IN
and stored
in L1; D1 is reverse biased and I
o
is supplied from the charge stored in C
o
. When Q1 opens, t
OFF
, voltage V1 will
rise positively to the point where D1 turns ON. The output current is now supplied through L1, D1 to the load and
any charge lost from C
o
during t
ON
is replenished. Here also, as in the step-down regulator, the current through
L1 has a DC component plus some ΔI
L
. ΔI
L
is again selected to be approximately 40% of I
L
. Figure 29 shows the
inductor's current in relation to Q1's ON and OFF times.
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