ICE1QS01 Infineon Technologies, ICE1QS01 Datasheet - Page 7

• Manufacturer Part Number: ICE1QS01
• Description: IC PFC CONTROLLER 8DIP
• Manufacturer: Infineon Technologies

Specifications of ICE1QS01

• Current - Startup: 60µA
• Voltage - Supply: 9 V ~ 20 V
• Operating Temperature: -25°C ~ 150°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Mode: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: ICE1QS01X; ICE1QS01XK; SP000014266

3
3.1
In the controller ICE2QS01, a power cell is integrated.
As shown in Figure 2, the power cell consists of a high
voltage device and a controller, whereby the high
voltage device is controlled by the controller. The
power cell provides a pre-charging of the VCC
capacitor till VCC voltage reaches the VCC turned-on
threshold V
may keep the VCC voltage at a constant value during
burst mode operation when the output voltage is pulled
down or the power from the auxiliary winding is not
enough, or when the IC is latched off in certain
protection mode.
Once the mains input voltage is applied, a rectified
voltage shows across the capacitor C
voltage device provides a current to charge the VCC
capacitor C
certain value, the amplitude of the current through the
high voltage device is only determined by its channel
resistance and can be as high as several mA. After the
VCC voltage is high enough, the controller controls the
high voltage device so that a constant current around
1mA is provided to charge the VCC capacitor further,
until the VCC voltage exceeds the turned-on threshold
V
VCC voltage increase near linearly.
Figure 3
The time taking for the VCC pre-charging can then be
approximately calculated as:
where I
cell which is 1.05mA, typically.
Exceeds the VCC voltage the turned-on threshold
V
the IC begins to operate with a soft-start. Due to power
consumption of the IC and the fact that still no energy
from the auxiliary winding to charge the VCC capacitor
before the output voltage is built up, the VCC voltage
Version 2.1
t
1
VCCon
VCCon
=
V
V
--------------------------------- -
VCCUVP
V
. As shown as the time phase I in Figure 3, the
VCC
I
of at time t
VCCon
VCCon
VCCcharge2
VCCch
VCCon
Functional Description
VCC Pre-Charging and Typical
VCC Voltage During Start-up
vcc
⋅
arg
VCC voltage at start up
C
. Before the VCC voltage reaches a
e2
vcc
is the charging current from the power
and the IC begins to operate, while it
1
, the power cell is switched off, and
i
t1
ii
t2
iii
bus
. The high
t
[1]
7
drops (Phase II). Once the output voltage is high
enough, the VCC capacitor receives then energy from
the auxiliary winding from the time point t
then will reach a constant value depending on output
load.
Since there is a VCC undervoltage protection, the
capacitance of the VCC capacitor should be selected to
be high enough to ensure that enough energy is stored
in the VCC capacitor so that the VCC voltage will never
touch the VCC under voltage protection threshold
V
the capacitance should fulfill the following requirement:
with I
3.2
At the time t
By this soft-start the switching stresses for the switch,
diode and transformer are minimised. The soft-start
implemented in the ICE2QS01 is a digital time-based
function. The preset soft-start time is 24ms with 8
steps. The internal reference for the regulation voltage
begins at 1.35V and with an increment of 0.35V for
each following step.
3.3
The PWM section of the IC can be divided into two
main portions: PWM controller for normal operation
and PWM controller for burst mode operation. The
PWM controller for normal operation will be described
in the following paragraphs, while the PWM controller
for burst mode operation will be discussed in the next
section.
The PWM controller for normal operation consists of
digital signal processing circuit including an up/down
counter, a zero-crossing counter (ZC-counter) and a
comparator, and analog circuit including a current
measurement unit and a comparator. The switch-on
and -off time point is determined by the digital circuit
and the analog circuit, respectively. As input
information for the switch-on determination, the zero-
crossing input signal and the value of the up/down
counter are needed, while the feedback signal v
and the current sensing signal v
the switch-off determination. Details about the
operation of the PWM controller in normal operation
are illustrated in the following paragraphs.
3.3.1
As mentioned above, the digital signal processing
circuit consists of an up/down counter, a zero-crossing
counter and a comparator. A ringing suppression time
C
VCCUVP
vcc
Quasi-Resonant PWM Controller
≥
VCCop
----------------------------------------------- -
V
before the output voltage is built up. Therefore,
I
VCCon
VCCop
the operating current of the controller.
Soft-start
1
Normal Operation
Switch-on Determination
, the IC begins to operate with a soft-start.
–
⋅
V
(
t
2
VCCUVP
–
t
1
Functional Description
)
CS
are necessary for
October 2007
ICE2QS01
2
on. The VCC
REG
[2]