Datasheet
Table Of Contents
- Figure 1. Typical topology
- Table 1. Device summary
- 1 Block diagram
- 2 Typical power
- 3 Pin settings
- 4 Electrical data
- 5 Typical electrical characteristics
- Figure 7. Current limit vs. TJ
- Figure 8. Switching frequency vs. TJ
- Figure 9. Drain start voltage vs. TJ
- Figure 10. HFB vs. TJ
- Figure 11. Brownout threshold vs. TJ
- Figure 12. Brownout hysteresis vs. TJ
- Figure 13. Brownout hysteresis current vs. TJ
- Figure 14. Operating supply current (not switching) vs. TJ
- Figure 15. Operating supply current (switching) vs. TJ
- Figure 16. Current limit vs. RLIM
- Figure 17. Power MOSFET ON resistance vs. TJ
- Figure 18. Power MOSFET breakdown voltage vs. TJ
- Figure 19. Thermal shutdown
- 6 Typical circuit
- 7 Efficiency performances for a typical flyback converter
- 8 Operation description
- 8.1 Power section and gate driver
- 8.2 High voltage startup generator
- 8.3 Power-up and soft-start
- 8.4 Power down operation
- 8.5 Auto-restart operation
- 8.6 Oscillator
- 8.7 Current mode conversion with adjustable current limit set point
- 8.8 Overvoltage protection (OVP)
- 8.9 About the CONT pin
- 8.10 Feedback and overload protection (OLP)
- 8.11 Burst mode operation at no load or very light load
- 8.12 Brownout protection
- 8.13 2nd level overcurrent protection and hiccup mode
- 9 Package mechanical data
- 10 Revision history
VIPER37 Operation description
Doc ID 022218 Rev 1 25/35
The resistor values are such that the current sourced and sunk by the CONT pin are within
the rated capability of the internal clamp.
Figure 28. OVP timing diagram
8.9 About the CONT pin
Referring to
Figure 29
, the features below can be implemented through the CONT pin:
1. Current limit set point
2. Overvoltage protection on the converter output voltage
Tabl e 11
, referring to
Figure 29
, lists the external resistance combinations needed to
activate one or more of the CONT pin functions.
Figure 29. CONT pin configuration
t
V
DS
VA
U
X
t
t
t
STROBE
t
COUNTER
RESET
t
COUNTER
STATUS
t
0
CONT
(pin 4)
sampling time
OVP
FAULT
0 0 0
0
→
1
1
→
2
2
→
0
0
→
1
1
→
2
2
→
3
3
→
4
0
ERULIAF POOL KCABDEEFECNABRUTSID YRAROPMETNOITAREPO LAMRON
t
V
DS
t
t
t
STROBE
t
COUNTER
RESET
t
COUNTER
STATUS
t
0
(pin 4)
OVP
FAULT
0 0 0
0
→
1
→
2
→
0
→
1
→
2
→
3
→
0
ERULIAF POOL KCABDEEFECNABRUTSID YRAROPMETNOITAREPO LAMRON
t
V
OVP
T
STROBE
+
-
Current Limit Comparator
To OVP Protection
R
OVP
R
LIM
D
AUX
SOFT
START
CONT
From SenseFET
Auxiliary
winding
To PWM Logic
OVP DETECTION
LOGIC
Curr. Lim.
BLOCK
OCP