CS1500 Datasheet, PDF (14/22 Pages) Cirrus Logic – Digital Power Factor Correction IC

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CONFIDENTIAL
CS1500
needed to meet the hold-up time required is defined by the
following equation:
C_out(hold)
=
----------------------------²-----^×-----^P----^O-----^×-----^t--^h---^o---^l-^d-----------------------------


V_lin
k
–
-^Δ----^V----^o---₂^u---^t-⁽--^r--ⁱ--^p--⁾_
2
–
(V_link(min))²
[Eq.18]
4.1.7 Overvoltage Protection
Overvoltage protection is activated when V_link exceeds 105%
of the nominal value:
V_ovp = V_link × 1.05
[Eq.19]
t_HOLD is the magnitude of the hold-up time in seconds. For
10 ms of hold-up time and V_link(min) of 300 V, the equation
becomes:
C_out(hold)
=
---------²-----^×-----⁹---⁰-----^×-----⁰---^.--⁰---¹---⁰-----------


400
–
1_--2--0_{--}
2
–
(
300
)²
=
27μF
Choose a 100 μF capacitor.
V_ovp = 400 × 1.05
V_ovp = 420V
While in overvoltage protection mode, gate drive output is
disabled. GD output is re-enabled when V_link falls below its
nominal value.
14
DS849A5