NCP1603D100R2 ON Semiconductor, NCP1603D100R2 Datasheet - Page 29

• Manufacturer Part Number: NCP1603D100R2
• Description: IC CTRLR PFC/PWM HV START 16SOIC
• Manufacturer: ON Semiconductor

Specifications of NCP1603D100R2

• Mode: Critical Conduction (CRM), Discontinuous Conduction (DCM)
• Frequency - Switching: 58kHz
• Current - Startup: 17µA
• Voltage - Supply: 9 V ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Switching Frequency: 405 KHz
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: NCP1603D100R2OSTR

PFC Toggling
the PFC−on or PFC−off can be very large. When the
NCP1603 circuit is operating at some conditions between
PFC on and off boundary, the duty ratio variation can lead
to unwanted on/off toggling in the PFC stage. A current
feedforward resistor R
between V
prevent the toggling. The value of R
current sense feedback resistor R
effect when V
(or PFC is on), the R
pin voltage and it allows the feedback voltage V
shift slightly but provide a dramatic duty cycle reduction
in Figure 77. It slight movement of the feedback voltage
can reduce the change to reach the PFC stage on/off
threshold. Hence, the current feedforward resistor can help
to improve the toggling.
The variation of the duty ratio in the PWM stage between
Figure 76. Feedforward Resistor R
R
aux
FF
aux
and CS2 pin (pins 1 and 3) in Figure 76 to
CS2
= 0 (or PFC is off). When V
FF
V
aux
FF
creates a positive offset on the CS2
is hence recommended to added
S2
R
FF
S2
and plays very little
is much larger than
FF
aux
V
Added
bulk
is available
FB2
to only
http://onsemi.com
29
V
V
Out 2
V
Figure 77. Timing Diagram of PWM Stage When R
FB2
CS2
3
aux
High duty when PFC is off.
is Added
Low duty when PFC is on.
FF