NCP1254 查看數據表（PDF） - ON Semiconductor

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NCP1254

Current-Mode PWM Controller for Off-line Power Supplies featuring Peak Power Excursion

ON Semiconductor 

NCP1254

Vbulk

OVP

Vout

.

.

OPP

.

NCP1254

1

6

2

5

3

4

ramp

comp.

Figure 1. Typical Application Schematic

Table 1. PIN FUNCTION DESCRIPTION

Pin No. Pin Name

Function

1

GND

−

2

FB

Feedback pin

3

OPP/OVP

Adjust the Over Power Protection

Latches off the part

4

CS

Current sense + ramp compensation

5

Vcc

Supplies the controller – protects the IC

6

DRV

Driver output

Description

The controller ground.

Hooking an optocoupler collector to this pin will allow regula-

tion via peak current mode control or frequency modulation in

high−power conditions.

A resistive divider from the auxiliary winding to this pin sets the

OPP compensation level. When brought above 3 V, the part is

fully latched off.

This pin monitors the primary peak current but also offers a

means to introduce slope compensation.

This pin is connected to an external auxiliary voltage. An OVP

comparator monitors this pin and offers a means to latch the

converter in fault conditions.

The driver’s output to an external MOSFET gate.

Table 2. OPTIONS AND ORDERING INFORMATION

Controller

Frequency

NCP1254ASN65T1G

65 kHz

NCP1254BSN65T1G

65 kHz

OCP Latched

Yes

No

OCP Auto−recovery

No

Yes

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