Datasheet

2525
=
35.7 k: x 1 nF
f
SW
=
R
T
x C
T
= 700 kHz
2525
=
700 kHz x 1 nF
= 35.7 k:
R
T
=
f
SW
x C
T
D
MAX
==
677.0
=
V21
V10V21 +
V
O
VV
IN-MINO
+
21V
=
21V + 70V
= 0.231
D
MIN
=
V
O
+ V
IN-MAX
V
O
533.0467.01D1'D
=
-
=
-
=
D
==
467.0
=
V21
V24V21 +
V
O
VV
INO
+
:
=
:x
=
x
=
95.1m3256rNr
LEDD
V21V5.36VNV
LEDO
=
x
=
x
=
LM3429, LM3429-Q1
SNVS616G –APRIL 2009–REVISED MAY 2013 www.ti.com
SPECIFICATIONS
N = 6
V
LED
= 3.5V
r
LED
= 325 mΩ
V
IN
= 24V
V
IN-MIN
= 10V
V
IN-MAX
= 70V
f
SW
= 700 kHz
V
SNS
= 100 mV
I
LED
= 1A
Δi
L-PP
= 500 mA
Δi
LED-PP
= 50 mA
Δv
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 kΩ therefore the f
SW
is:
(95)
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