ICE3BR1065J_11 INFINEON [Infineon Technologies AG], ICE3BR1065J_11 Datasheet - Page 16

• Manufacturer Part Number: ICE3BR1065J_11
• Manufacturer: INFINEON [Infineon Technologies AG]

and FB signal is still below 1.35V, the system enters
the Active Burst Mode. This time window prevents a
sudden entering into the Active Burst Mode due to
large load jumps.
After entering Active Burst Mode, a burst flag is set and
the internal bias is switched off in order to reduce the
current consumption of the IC to approx. 450uA.
It needs the application to enforce the VCC voltage
above the Undervoltage Lockout level of 10.5V such
that the Startup Cell will not be switched on
accidentally. Or otherwise the power loss will increase
drastically. The minimum VCC level during Active Burst
Mode depends on the load condition and the
application. The lowest VCC level is reached at no load
condition.
3.7.2.2
After entering the Active Burst Mode, the FB voltage
rises as V
inactive PWM section. The comparator C6a monitors
the FB signal. If the voltage level is larger than 3.5V, the
internal circuit will be activated; the Internal Bias circuit
resumes and starts to provide switching pulse. In
Active Burst Mode the gate G10 is released and the
current limit is reduced to 0.34V, which can reduce the
conduction loss and the audible noise. If the load at
V
3.05V. At this level the C6b deactivates the internal
circuit again by switching off the internal Bias. The gate
G11 is active again as the burst flag is set after entering
Active Burst Mode. In Active Burst Mode, the FB
voltage is changing like a saw tooth between 3.05V and
3.5V (see figure 24).
3.7.2.3
The FB voltage will increase immediately if there is a
high load jump. This is observed by the comparator C4.
Since the current limit is app. 34% during Active Burst
Mode, it needs a certain load jump to rise the FB signal
to exceed 4.0V. At that time the comparator C4 resets
the Active Burst Mode control which in turn blocks the
comparator C12 by the gate G10. The maximum
current can then be resumed to stabilize the V
Version 2.0
OUT
is still kept unchanged, the FB signal will drop to
OUT
Working in Active Burst Mode
Leaving Active Burst Mode
starts to decrease, which is due to the
OUT.
16
Figure 24
10.5V
3.8mA
450uA
0.34V
3.5V
3.05V
1.35V
1.03V
4.0V
Blanking Timer
V
V
V
V
I
VCC
OUT
FB
VCC
CS
20ms Blanking Time
Current limit level
during Active Burst
Mode
Signals in Active Burst Mode
Entering
Active Burst
Mode
Functional Description
Leaving
Active Burst
Mode
CoolSET
ICE3BR1065J
28 Dec 2011
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