Datasheet

2
HALF _ CYCLES
CVINS _ dischrg
LINE (min)
N
t
f
=
´
(128)
2 5
25 6
2 47
CVINS _ dischrg
.
t . ms
Hz
= =
´
(129)
2
2
1 2
0 9
CVINS _ dischrg
VINS
BROWNOUT _th(min)
VINS
VINS
IN _ RMS (min)
VINS VINS
t
C
VINS
R ln
R
. V
R R
-
=
é ù
ê ú
ê ú
´
ê ú
æ ö
´ ´
ê ú
ç ÷
+
ê ú
è ø
ë û
(130)
25 6
0 63
0 76
100
100
0 9 85
6 5 100
VINS
. ms
C . F
. V
k ln
k
. V
. M k
m
-
= =
é ù
ê ú
ê ú
W´
W
æ ö
ê ú
´ ´
ç ÷
ê ú
W + W
è ø
ë û
(131)
UCC28019A
SLUS828B – DECEMBER 2008 – REVISED APRIL 2009 .................................................................................................................................................. www.ti.com
The capacitor on VINS, C
VINS
, is selected so that it's discharge time is greater than the output capacitor hold up
time. C
OUT
was chosen to meet one-cycle hold-up time so C
VINS
will be chosen to meet 2.5 half-line cycles.
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