|
CS1500_1 Datasheet, PDF (14/22 Pages) Cirrus Logic – Digital Power Factor Correction IC | |||
|
◁ |
Jul ?$shortyear>
CONFIDENTIAL
CS1500
needed to meet the hold-up time required is defined by the
following equation:
Cout(hold)
=
----------------------------2-----Ã-----P----O-----Ã-----t--h---o---l-d-----------------------------
ï¦
ï¨
Vlin
k
â
-Î---V-----o---2u---t-(--r--i--p--)ï¸ï¶
2
â
(Vlink(min))2
[Eq.18]
4.1.7 Overvoltage Protection
Overvoltage protection is activated when Vlink exceeds 105%
of the nominal value:
Vovp = Vlink à 1.05
[Eq.19]
tHOLD is the magnitude of the hold-up time in seconds. For
10 ms of hold-up time and Vlink(min) of 300 V, the equation
becomes:
Cout(hold)
=
---------2-----Ã-----9---0-----Ã-----0---.--0---1---0-----------
ï¦
ï¨
400
â
1--2--0--ï¸ï¶
2
â
(
300
)2
=
27μF
Choose a 100 μF capacitor.
Vovp = 400 Ã 1.05
Vovp = 420V
While in overvoltage protection mode, gate drive output is
disabled. GD output is re-enabled when Vlink falls below its
nominal value.
14
DS849A7
|
▷ |