LM2524DN National Semiconductor, LM2524DN Datasheet - Page 17
![no-image](/images/manufacturer_photos/0/4/469/national_semiconductor_sml.jpg)
LM2524DN
Manufacturer Part Number
LM2524DN
Description
IC,SMPS CONTROLLER,VOLTAGE-MODE,BIPOLAR,DIP,16PIN,PLASTIC
Manufacturer
National Semiconductor
Datasheet
1.LM2524DN.pdf
(22 pages)
Specifications of LM2524DN
Rohs Compliant
NO
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM2524DN
Manufacturer:
NS/国半
Quantity:
20 000
Typical Applications
THE STEP-UP SWITCHING REGULATOR
Figure 18 shows the basic circuit for a step-up switching
regulator. In this circuit Q1 is used as a switch to alternately
apply V
and energy is drawn from V
biased and I
Q1 opens, t
where D1 turns ON. The output current is now supplied
through L1, D1 to the load and any charge lost from C
during t
regulator, the current through L1 has a DC component plus
some ∆I
I
ON and OFF times.
Since ∆I
and neglecting V
The above equation shows the relationship between V
and duty cycle.
L
. Figure 19 shows the inductor’s current in relation to Q1’s
FIGURE 18. Basic Step-Up Switching Regulator
IN
ON
L
L
. ∆I
+ = ∆I
across inductor L1. During the time, t
is replenished. Here also, as in the step-down
o
OFF
L
is supplied from the charge stored in C
is again selected to be approximately 40% of
L
, voltage V1 will rise positively to the point
−, V
SAT
IN
FIGURE 19. Relation of Switch Timing to Inductor Current in Step-Up Regulator
and V
t
ON
= V
D1
IN
and stored in L1; D1 is reverse
o
t
OFF
− V
(Continued)
IN
t
OFF
,
ON
, Q1 is ON
00865023
o
. When
IN
, V
o
o
17
In calculating input current I
tor’s DC current, assume first 100% efficiency:
for η = 100%, P
OUT
= P
IN
IN(DC)
00865024
, which equals the induc-
www.national.com