ICE2QR2280Z-1 Datasheet, PDF (11/21 Pages) Infineon Technologies AG – Off-Line SMPS Quasi-Resonant PWM Controller with integrated

CoolSET^® - Q1
ICE2QR2280Z-1
Functional Description
immediately after leaving Active Burst Mode. This is
helpful to decrease the output voltage undershoot.
V_FB
VFBLB
V_FBBOn
VFBBOff
Entering
Active Burst
Mode
Leaving
Active Burst
Mode
VFBEB
Time to 7^th zero and
t
V_CS
Blanking Window (t_BEB)
1.0V
Current limit level during
Active Burst Mode
V_CSB
V_VCC
t
VVCCoff
V_O
t
Max. Ripple < 1%
t
Figure 8 Signals in Active Burst Mode
voltage, the 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 t_{OLP_B} (30ms), the IC enters auto-restart mode. The
blanking time here enables the converter to provide a
peak power in case the increase in V_FB 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 v_ZCOVP, the IC is latched off after the preset
blanking time t_ZCOVP. This latch off mode can only be
reset if the Vcc < V_VCCPD (5.2V).
If the junction temperature of IC exceeds T_jCon (140 °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 v_CSSW 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 v_VCCoff (9.85V) and then the startup cell is
activated. The VCC voltage is then charged to v_VCCon
(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 CoolSET^® - Q1. Once the gate
voltage is high and longer than t_OnMAx, the switch is
turned off immediately.
3.6
Protection Functions
The IC provides full protection functions. The following
table summarizes these protection functions.
Table 2 Protection features
VCC Overvoltage
VCC Undervoltage
Overload/Open Loop
Over temperature
Output Overvoltage
Short Winding
Auto Restart Mode
Auto Restart Mode
Auto Restart Mode
Auto Restart Mode
Latched Off Mode
Latched Off Mode
During operation, the VCC voltage is continuously
monitored. In case of an under-voltage or an over-
Version 2.1
11
March 7, 2013