ICE2QR1765Z Datasheet, PDF (11/22 Pages) Infineon Technologies AG – Off-Line SMPS Quasi-Resonant PWM Controller with integrated 650V CoolMOS® and startup cell in DIP-7

CoolSET^® - Q1
ICE2QR1765Z
Functional Description
immediately after leaving Active Burst Mode. This is
helpful to decrease the output voltage undershoot.
V_FB
V_FBLB
V_FBBOn
V_FBBOff
Entering
Active Burst
Mode
Leaving
Active Burst
Mode
V_FBEB
time to 7^th zero and
t
V_CS
blanking Window (t_BEB)
1.0V
V_CSB
Current limit level
during Active Burst
Mode
V_VCC
t
V_VCCoff
V_O
t
Max. Ripple < 1%
IC is reset and the main power switch is then kept off.
After the VCC voltage falls below the threshold V_VCCoff,
the startup cell is activated. The VCC capacitor is then
charged up. Once the voltage exceeds the threshold
V_VCCon, the IC begins 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_FB is due to a sudden
load increase. 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 v_ZCOVP, the IC is latched off 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_CSSW during on-time of the power
switch, 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 ICE2QR1765Z. Once the gate
voltage is high and longer than t_OnMAx, the switch is
turned off immediately.
t
Figure 8 Signals in Active Burst Mode
3.6 Protection Functions
The IC provides full protection functions. The following
table summarizes these protection functions.
Table 2 Protection features
VCC Overvoltage
Auto Restart Mode
VCC Undervoltage
Auto Restart Mode
Overload/Open Loop
Auto Restart Mode
Over temperature
Auto Restart Mode
Output Overvoltage
Latched Off Mode
Short Winding
Latched Off Mode
During operation, the VCC voltage is continuously
monitored. In case of an under- or an over-voltage, the
Version 2.1
11
August 30, 2011