NCP1250 查看數據表（PDF） - ON Semiconductor

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NCP1250

Current-Mode PWM Controller for Off-line Power Supplies

ON Semiconductor 

NCP1250

ELECTRICAL CHARACTERISTICS

(For typical values TJ = 25C, for min/max values TJ = −40C to +125C, Max TJ = 150C, VCC = 12 V unless otherwise noted)

Symbol

Rating

Pin Min Typ Max Unit

INTERNAL OSCILLATOR

fjitter

Frequency jittering in percentage of fOSC

fswing Swing frequency

FEEDBACK SECTION

−

5

%

−

240

Hz

Rup

Internal pull−up resistor

Req

Equivalent ac resistor from FB to GND

Iratio

Pin 2 to current setpoint division ratio

Vfreeze Feedback voltage below which the peak current is frozen

FREQUENCY FOLDBACK

2

20

kW

2

16

kW

−

4.2

2

1.05

V

Vfold

Ftrans

Vfold,end

Vskip

Skip

hysteresis

Frequency folback level on the feedback pin – [45% of maximum peak current

Transition frequency below which skip−cycle occurs

End of frequency foldback feedback leve, Fsw = Fmin

Skip−cycle level voltage on the feedback pin

Hysteresis on the skip comparator – (Note 5)

−

1.5

V

−

22

26

30 kHz

350

mV

−

300

mV

−

30

mV

INTERNAL SLOPE COMPENSATION

Vramp Internal ramp level @ 25C – (Note 7)

Rramp Internal ramp resistance to CS pin

PROTECTIONS

4

2.5

V

4

20

kW

Vlatch Latching level input

3 2.7 3.0 3.3

V

Tlatch−blank Blanking time after drive turn off

1

1.0

ms

Tlatch−count Number of clock cycles before latch confirmation

−

4.0

Tlatch−del OVP detection time constant

1

600

ns

Timer Internal auto−recovery fault timer duration

− 100 130 160 ms

4. For design robustness, we recommend to inject 60 mA as a minimum at the lowest input line voltage.

5. Guaranteed by design

6. See characterization table for linearity over negative bias voltage

7. A 1 MW resistor is connected from pin 3 to the ground for the measurement.

http://onsemi.com

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