NCP1654_09 Datasheet, PDF (5/23 Pages) ON Semiconductor – Power Factor Controller for Compact and Robust, Continuous Conduction Mode Pre-Converters

NCP1654
DETAILED PIN DESCRIPTIONS
Pin Symbol
Name
1
GND
Ground
2
V_in
Multiplier
Voltage
3
CS
Current Sense
Input
4
V_BO
Brown−Out / In
5
V_control Control Voltage /
Soft−Start
6
V_FB
Feed−Back /
Shutdown
7
V_CC
Supply Voltage
8
DRV
Drive Output
Function
−
This pin provides a voltage V_M for the PFC duty cycle modulation. The input impedance of the
PFC circuits is proportional to the resistor R_M externally connected to this pin. The device op-
erates in average current mode if an external capacitor C_M is connected to the pin. Otherwise,
it operates in peak current mode.
This pin sources a current I_CS which is proportional to the inductor current I_L. The sense cur-
rent I_CS is for overcurrent protection (OCP), overpower limitation (OPL) and PFC duty cycle
modulation. When I_CS goes above 200 mA, OCP is activated and the Drive Output is disabled.
Connect a resistor network among the rectified input voltage, BO pin, and ground. And connect
a capacitor between BO pin and ground. BO pin detects a voltage signal proportional to the
average input voltage.
When V_BO goes below V_BOL, the circuit that detects too low input voltage conditions (brown−
out), turns off the output driver and keeps it in low state until V_BO exceeds V_BOH.
This signal which is proportional to the RMS input voltage V_ac is also for overpower limitation
(OPL) and PFC duty cycle modulation.
The voltage of this pin V_control directly controls the input impedance. This pin is connected to
external type−2 compensation components to limit the V_control bandwidth typically below 20 Hz
to achieve near unity power factor.
The device provides no output when V_control < V_control(min). When it starts operation, the power
increases slowly (soft−start).
This pin receives a feedback signal V_FB that is proportional to the PFC circuits output voltage.
This information is used for both the output regulation, the overvoltage protection (OVP), and
output undervoltage protection (UVP) to protect the system from damage at feedback abnor-
mal situation.
When V_FB goes above 105% V_REF, OVP is activated and the Drive Output is disabled.
When V_FB goes below 8% V_REF, the device enters a low−consumption shutdown mode.
This pin is the positive supply of the IC. The circuit typically starts to operate when V_CC ex-
ceeds 10.5 V and turns off when V_CC goes below 9 V. After start−up, the operating range is 9 V
up to 20 V.
The high current capability of the totem pole gate drive (±1.5 A) makes it suitable to effectively
drive high gate charge power MOSFET.
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