NCP1231 Просмотр технического описания (PDF) - ON Semiconductor

Номер в каталоге

Компоненты Описание

производитель

NCP1231

Low−Standby Power High Performance PWM Controller

ON Semiconductor 

HV

to PFC’s VCC

+

NCP1231

OVP

BO/OVP

1

8

SS

2

7

3

6

4

5

NCP1231

Ramp

+

Vout

GND

GND

Figure 1. Typical Application Example

PIN FUNCTION DESCRIPTION

Pin No. Pin Name

Function

Pin Description

1

PFC VCC Directly powers the PFC This pin is a direct connection to the VCC pin (Pin 6) via a low impedance switch.

front−end stage

In standby and during the startup sequence, the switch is open and the PFC VCC

is shutdown. As soon as the aux. winding is stabilized, Pin 1 connects to the VCC

pin and provides bias to the PFC controller. It goes down in standby and fault

conditions.

2

FB

Feedback Signal

An optocoupler collector pulls this pin low to regulate. When the current setpoint

falls below 25% of the maximum peak, the controller skips cycles.

3

CS

Current Sense

This pin incorporates two different functions: the standard sense function and an

internal ramp compensation signal.

4

GND

IC Ground

−

5

DRV

Driver Output

With a drive capability of +500 mA / −800 mA, the NCP1231 can drive large Qg

MOSFETs.

6

VCC

VCC Input

The controller accepts voltages up to 18 V and features a UVLO of 7.7 V typical.

7

SS

To provide an internal This pin provides three different functions, via a capacitor to ground, saw tooth

(Soft−Start) ramp timing for different signal whose function is to create a soft−start, frequency dithering and 100 msec

usages

fault timer.

8

BO/OVP Brown−Out and OVP

By connecting this pin to a resistive divider, the controller ensures operation at a

safe mains level. If an external event brings this pin above 4 V, the controller is

permanently latched−off.

http://onsemi.com

2

Share Link: