ice2qr4765z Infineon Technologies Corporation, ice2qr4765z Datasheet - Page 11

• Manufacturer Part Number: ice2qr4765z
• Description: Off-line Smps Quasi-resonant Pwm Controller With Integrated 650v Coolmos And Startup Cell In Dip- 7
• Manufacturer: Infineon Technologies Corporation

will be set to 1 immediately after leaving Active Burst Mode.
This is helpful to decrease the output voltage undershoot.
Figure 8
3.6
The IC provides full protection functions. The following
table summarizes these protection functions.
Table 2
During operation, the VCC voltage is continuously
monitored. In case of an under- or an over-voltage, the IC is
Version 2.0
VCC Overvoltage
VCC Undervoltage
Overload/Open Loop
Over temperature
Output Overvoltage
Short Winding
V
V
V
V
V
V
V
1.0V
V
V
FBBOn
FBBOff
V
VCCoff
FB
CSB
FBLB
FBEB
VCC
O
CS
Current limit level
during Active Burst
Mode
Protection Functions
blanking Window (t
time to 7
Protection features
Signals in Active Burst Mode
Max. Ripple < 1%
Entering
Active Burst
Mode
th
zero and
BEB
)
Auto Restart Mode
Auto Restart Mode
Auto Restart Mode
Auto Restart Mode
Latched Off Mode
Latched Off Mode
Leaving
Active Burst
Mode
t
t
t
t
11
reset and the main power switch is then kept off. After the
VCC voltage falls below the threshold V
cell is activated. The VCC capacitor is then charged up.
Once the voltage exceeds the threshold V
to operate with a new soft-start.
In case of open control loop or output over load, the feedback
voltage will be pulled up. After a blanking time of 24ms, the
IC enters auto-restart mode. The blanking time here enables
the converter to provide a max. power in case the increase in
V
power switch, the voltage at the zero-crossing pin is
monitored for output over-voltage detection. If the voltage is
higher than the preset threshold v
after the preset blanking time. This latch off mode can only
be reset if the Vcc <6.23V.
If the junction temperature of IC exceeds 140 °C, the IC
enters into autorestart mode (OTP).
If the voltage at the current sensing pin is higher than the
preset threshold v
the IC is latched off. This is short-winding protection.
During latch-off protection mode, the VCC voltage drops to
10.5V and then the startup cell is activated. The VCC voltage
is then charged to 18V. The startup cell is shut down again.
This action repeats again and again.
There is also a maximum on time limitation implemented
inside the ICE2QR4765. Once the gate voltage is high and
longer than t
FB
is due to a sudden load increase. During off-time of the
OnMAx
CSSW
, the switch is turned off immediately.
during on-time of the power switch,
Functional Description
ZCOVP
CoolSET
ICE2QR4765Z
, the IC is latched off
VCCon
VCCoff
May 25, 2011
, the IC begins
, the startup
®
- Q1