IR1150LS International Rectifier, IR1150LS Datasheet - Page 8

• Manufacturer Part Number: IR1150LS
• Description: uPFC One Cycle Control PFC IC
• Manufacturer: International Rectifier

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COM: Ground
This is the ground potential pin of the integrated con-
trol circuit. All internal devices are referenced to this
point.
V
The output voltage of the boost converter is sensed
via a resistive divider and fed into this pin, which is
the inverting input of the output voltage error amplifier.
The impedance of the divider string must be low
enough so as to not introduce substantial error due
to the input bias currents of the amplifier, yet high
enough so as to minimize power dissipation. A typical
value of external divider impedance is 1M .
The error amplifier is a transconductance type which
yields high output impedance, thus increasing the
noise immunity of the error amplifier output. This also
eliminates input divider string interaction with
compensation feedback capacitors and reducing the
loading of divider string due to a low impedance
output of the amplifier.
COMP: Voltage Loop Compensation
External circuitry from this pin to ground
compensates the system voltage loop and soft start
time. This is the output of the voltage error amplifier.
This pin will be discharged via internal resistance
when a fault mode occurs.
GATE: Gate Drive Output
This is the gate drive output of the IC. Drive voltage is
internally limited and provides ±1.5A peak with
matched rise and fall times.
FREQ: Frequency Set
This is the user programmable frequency pin. An
external resistor from this pin to the COM pin pro-
grams the frequency. The operational switching fre-
quency range for the device is 50kHz – 200kHz.
Detailed Pin Description
FB
: Output Voltage Feedback
I
This pin is the inverting Current Sense Input & Peak
Current Limit. The voltage at this pin is the negative
voltage drop, sensed across the system current
sense resistor, representing the inductor current.
This voltage is fed into the Peak Current Limit pro-
tection comparator with threshold arond -1V. This pro-
tection circuit incorporates a leading edge blanking
circuit following the comparator to improve noise
immunity of the protection process.
The current sense signal is also fed into the current
sense amplifier. The signal is amplified, filtered of
high frequency noise and then injected into a sum-
ming node where it is subtracted from the compen-
sation voltage V
The signal on this pin must be previously filtered
with an RC cell to provide additional noise immunity.
The input impedance of this pin is 5k .
V
This is the supply voltage pin of the IC and it is
monitored by the under voltage lockout circuit. It is
possible to turn off the IC by pulling this pin below
the minimum turn off threshold voltage, without
damage to the IC.
To prevent noise problems, a bypass ceramic
capacitor connected to V
placed as close as possible to the IR1150S.
This pin is not internally clamped, therefore damage
will occur if the maximum voltage is exceeded.
OVP/EN: Over Voltage Protection / Enable
This pin is the input to the over voltage protection
comparator the threshold of which is internally pro-
grammed to 105.5% of V
A resistive divider feeds this pin from the output volt-
age to COM and inhibits the gate drive whenever the
threshold is exceeded. Normal operation resumes
when the voltage level on this pin decreases to be-
low the pin threshold.
This pin is also used to activate “sleep” mode by
pulling the voltage level below 0.62V (typ).
SNS
CC
: Supply Voltage
: Current Sense input
IR1150S/IR1150IS
COMP
.
REF
CC
.
and COM should be
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