Datasheet

www.ti.com
Brown Out Protection
0
150
VINS VINS _ V
I I= ´
150 0 1 15
VIN S
I . A Am m= ´ =
75
AC( on )
V V=
65
AC ( off )
V V=
1
2
AC( on ) F _ BRIDGE ENABLE _th(max)
VINS
VINS
V V VINS
R
I
´ - -
=
1
2 75 0 95 1 6
6 9
15
VINS
V . V . V
R . M
Am
´ - -
= = W
1
2
2
ENABLE _ th(max) VINS
VINS
AC( on ) ENABLE _th(max) F _ BRIDGE
VINS R
R
V VINS V
´
=
´ - -
2
1 6 6 5
100
2 75 1 6 0 95
VINS
. V . M
R k
V . V . V
´ W
= = W
´ - -
UCC28019
SLUS755B – APRIL 2007 – REVISED DECEMBER 2007
Select the top divider resistor into the VINS pin so as not to contribute excessive power loss. The extremely low
bias current into VINS means the value of R
VINS1
could be hundreds of megaohms. For practical purposes, a
value less than 10 M Ω is usually chosen. Assuming approximately 150 times the input bias current through the
resistor dividers will result in an R
VINS1
that is less than 10 M Ω , so as to not contribute excessive noise, and still
maintain minimal power loss. The brown out protection will turn off the gate drive when the input falls below the
user programmable minimum voltage, V
AC(off)
, and turn on when the input rises above V
AC(on)
.
A 6.5-M resistance is chosen.
Copyright © 2007, Texas Instruments Incorporated Submit Documentation Feedback 41
Product Folder Link(s): UCC28019