ALTAIR04-900TR View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ALTAIR04-900TR' PDF : 29 Pages View PDF
ALTAIR04-900
Application information
Figure 17. Load-dependent operating modes: timing diagrams
COMP
VCOMPL
65 mV
hys ter.
IDS
5.8
Normal-mode
TSTA R T
TS TA RT
TS TA R T
Burst-mode
TST AR T
Normal-mode
Soft-start and starter block
The soft-start feature is automatically implemented by the constant current block, as the
primary peak current is limited on the CREF capacitor.
During the startup, as the output voltage is zero, IC starts in CC-mode without high peak
current operations. The voltage on the output capacitor increases slowly and the soft-start
feature is assured.
Actually the CREF value is not important to define the soft-start time, as its duration depends
on other circuit parameters, such as: transformer ratio, sense resistor, output capacitors and
load. The user can define the best appropriate value.
DocID18211 Rev 3
19/29
29
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