VIPER17 STMicroelectronics, VIPER17 Datasheet - Page 22

• Manufacturer Part Number: VIPER17
• Description: VIPerPlus family: fixed frequancy high performance off line high voltage converter
• Manufacturer: STMicroelectronics

Operation descriptions
22/31
Equation 7
Equation 8
The R
The C
The
considered instead of C
satisfy, in all case, the loop stability and the enough OLP delay time alike.
Figure 28. FB pin configuration
Figure 29. FB pin configuration
Equation 5
FB(DYN)
FB1
capacitor fixes the OLP delay and usually C
is the dynamic resistance seen by the FB pin.
can be still used to calculate the OLP delay time but C
Rfb1
Cfb1
FB
. Using the alternative compensation network, the designer can
Cfb
f
f
PFB
PFB
Cfb
Doc ID 14419 Rev 7
1
=
=
2
2
⋅
⋅
⋅ π
⋅ π
CONTROL
R
C
C
PWM
FB
FB
FB
CONTROL
PWM
BURST-MODE
1
(
DYN
References
⋅
⋅
(
(
R
R
1
FB
)
FB
References
+
V FBolp
1
(
DYN
R
+
V FBolp
FB
R
FB1
)
FB
OLP comparator
1
⋅
R
(
DYN
results much higher than C
BURST-MODE
PWM
OLP comparator
FB
From sense FET
+
+
-
-
LOGIC
1
)
BURST-MODE
)
)
PWM
From R
+
+
-
-
LOGIC
SENSE
To disable logic
To PWM Logic
To disable logic
FB1
BURST
To GATE driver
BURST
has to be
VIPER17
FB
.