VIPER25 STMicroelectronics, VIPER25 Datasheet - Page 30

• Manufacturer Part Number: VIPER25
• Description: VIPerPlus family: quasi-resonant high performance off line high voltage converter
• Manufacturer: STMicroelectronics

Operation description
30/40
Equation 11
The R
page
The C
Equation 8 on page 29
considered instead of C
satisfy, in all case, the loop stability and the enough OLP delay time alike.
Figure 34. FB pin configuration
Figure 35. FB pin configuration
8.
FB1
FB(DYN)
capacitor fixes the OLP delay and usually C
is the dynamic resistance seen by the FB pin and reported on
Rfb1
Cfb1
FB
can be still used to calculate the OLP delay time but C
. Using the alternative compensation network, the designer can
Cfb
f
PFB
Cfb
Doc ID 15585 Rev 4
1
=
2
⋅
⋅ π
CONTROL
PWM
C
FB
CONTROL
REFERENCES
BURST-MODE
PWM
1
⋅
REFERENCES
(
BURST-MODE
R
1
FB
1
4.8V
+
FB1
R
4.8V
FB
OLP comparator
(
results much higher than C
DYN
BURST-MODE
PWM
From sense FET
+
+
OLP comparator
-
-
LOGIC
)
BURST-MODE
)
PWM
From sense FET
+
+
-
-
LOGIC
To disable logic
To PWM Logic
To disable logic
BURST
To PWM Logic
BURST
Table 8 on
FB1
has to be
VIPER25
FB
. The