Quasi-Resonant, 800V CoolSET™ in DS0-12 Package
Functional Description
the startup cell is activated. The VCC capacitor is then charged up. Once the voltage exceeds the threshold
VVCCon, the IC begins to operate with a new soft-start.
Table 3
Protection Function
Failure Condition
Protection Mode
Auto Restart
VVCC > 25 V & last for 10 μs (normal
VCC Overvoltage
mode only)
Auto Restart
VCC Undervoltage/ Short
Optocoupler
VVCC < 10.5 V
Auto Restart
Auto Restart
Overload/Open Loop
VFB > 4.5 V & last for 30 ms
TJ > 140 °C
Over Temperature (Controller
Junction)
Latch
Latch
Output Overvoltage
Short Winding
VZCOVP > 3.7 V & last for 100 μs
VCSSW > 1.68 V & last for 190 ns
In case of open control loop or output over load, the feedback voltage will be pulled up. After a blanking time of
tOLP_B (30 ms), the IC enters auto-restart mode. The blanking time here enables the converter to provide a peak
power in case the increase in VFB is due to a sudden load increase. This output over load protection is disabled
during burst mode.
During off-time of the 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 VZCOVP, the IC is latched off after the preset blanking
time tZCOVP. This latch off mode can only be reset if the VVCC < VVCCPD
.
If the junction temperature of IC controller exceeds TjCon (130 °C), the IC enters into OTP auto restart mode. This
OTP is disabled during burst mode.
If the voltage at the current sensing pin is higher than the preset threshold VCSSW during on-time of the power
switch, the IC is latched off. This is short-winding protection. The short winding protection is disabled during
burst mode.
During latch-off protection mode, the VCC voltage drops to VVCCoff (10.5 V) and then the startup cell is activated.
The VCC voltage is then charged to VVCCon (18 V). The startup cell is shut down again. This action repeats again
and again.
There is also a maximum on time limitation implemented inside the CoolSET™ Q1. Once the gate voltage is high
and longer than tOnMax, the switch is turned off immediately.
Data Sheet
12
Revision 1.0
2016-05-12
INFINEON [ Infineon ]
