Texas Instruments LM3429 Evaluation Boards LM3429BKBSTEVAL/NOPB LM3429BKBSTEVAL/NOPB Datenbogen
Produktcode
LM3429BKBSTEVAL/NOPB
25
25
=
35.7 k
:
x 1 nF
f
SW
=
R
T
x C
T
= 700 kHz
25
25
=
700 kHz x 1 nF
= 35.7 k
:
R
T
=
f
SW
x C
T
D
MAX
=
=
677
.
0
=
V
21
V
10
V
21 +
V
O
V
V
IN-MIN
O
+
21V
=
21V + 70V
= 0.231
D
MIN
=
V
O
+ V
IN-MAX
V
O
533
.
0
467
.
0
1
D
1
'
D
=
-
=
-
=
D
=
=
467
.
0
=
V
21
V
24
V
21 +
V
O
V
V
IN
O
+
:
=
:
x
=
x
=
95
.
1
m
325
6
r
N
r
LED
D
V
21
V
5
.
3
6
V
N
V
LED
O
=
x
=
x
=
SNVS616G – APRIL 2009 – REVISED MAY 2013
SPECIFICATIONS
N = 6
V
LED
= 3.5V
r
LED
= 325 m
Ω
V
IN
= 24V
V
IN-MIN
= 10V
V
IN-MAX
= 70V
f
SW
= 700 kHz
V
SNS
= 100 mV
I
LED
= 1A
Δ
i
L-PP
= 500 mA
Δ
i
LED-PP
= 50 mA
Δ
v
IN-PP
= 1V
I
LIM
= 6A
V
TURN-ON
= 10V
V
HYS
= 3V
V
TURN-OFF
= 40V
V
HYSO
= 10V
1. OPERATING POINT
Solve for V
O
and r
D
:
(88)
(89)
Solve for D, D', D
MAX
, and D
MIN
:
(90)
(91)
(92)
(93)
2. SWITCHING FREQUENCY
Assume C
T
= 1 nF and solve for R
T
:
(94)
The closest standard resistor is actually 35.7 k
Ω
therefore the f
SW
is:
(95)
32
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