NCP1246-D View Datasheet(PDF) - ON Semiconductor

Part Name

Description

Manufacturer

NCP1246-D

Fixed Frequency Current Mode Controller for Flyback Converters

ON Semiconductor 

NCP1246

ELECTRICAL CHARACTERISTICS (For typical values TJ = 25°C, for min/max values TJ = −40°C to +125°C, VHV = 125 V,

VCC = 11 V unless otherwise noted)

Characteristics

Test Condition

Symbol

Min

Typ

Max

OSCILLATOR

Maximum duty cycle (corresponding to

maximum on time at maximum switching

frequency)

fOSC = 65 kHz

fOSC = 100 kHz

DMAX

−

80

−

Frequency jittering amplitude, in percentage

of FOSC

Frequency jittering modulation frequency

FREQUENCY FOLDBACK

Ajitter

Fjitter

±4

±6

±8

85

125

165

Feedback voltage threshold below which

frequency foldback starts

VFB(foldS)

1.8

2.0

2.2

Feedback voltage threshold below which

frequency foldback is complete

VFB(foldE)

0.8

0.9

1.0

Minimum switching frequency

OUTPUT DRIVER

VFB = Vskip(in) + 0.1

fOSC(min)

23

27

32

Rise time, 10 to 90% of VCC

VCC = VCC(min) + 0.2 V,

CDRV = 1 nF

trise

−

40

70

Fall time, 90 to 10% of VCC

VCC = VCC(min) + 0.2 V,

CDRV = 1 nF

tfall

−

40

70

Current capability

VCC = VCC(min) + 0.2 V,

CDRV = 1 nF

DRV high, VDRV = 0 V

DRV low, VDRV = VCC

IDRV(source)

−

500

−

IDRV(sink)

−

800

−

Clamping voltage (maximum gate voltage)

VCC = VCCmax – 0.2 V, DRV high, VDRV(clamp)

11

13.5

16

RDRV = 33 kW, Cload = 220 pF

High−state voltage drop

VCC = VCC(min) + 0.2 V,

VDRV(drop)

−

−

1

RDRV = 33 kW, DRV high

CURRENT SENSE

Input Pull−up Current

Maximum internal current setpoint

Propagation delay from VIlimit detection to

DRV off

VCS = 0.7 V

VFB > 3.5 V

VCS = VILIM

Ibias

VILIM

tdelay

−

1

−

0.66 0.70 0.74

−

80

110

Leading Edge Blanking Duration for VILIM

Threshold for immediate fault protection

activation

tLEB

VCS(stop)

200

250

320

0.95 1.05 1.15

Leading Edge Blanking Duration for VCS(stop)

(Note 6)

tBCS

90

120

150

Soft−start duration

Frozen current setpoint

INTERNAL SLOPE COMPENSATION

From 1st pulse to VCS = VILIM

tSSTART

VI(freeze)

8

11

14

275

300

325

Slope of the compensation ramp

FEEDBACK

Scomp(65kHz)

−

−32.5

−

Scomp(100kHz)

−

−50

−

Internal pull−up resistor

TJ = 25°C

RFB(up)

15

20

25

VFB to internal current setpoint division ratio

KFB

4.7

5

5.3

5. Internal supply current only, currents sourced via FB pin is not included (current is flowing in GND pin only).

6. Guaranteed by design.

7. CS pin source current is a sum of Ibias and IOPC, thus at VHV = 125 V is observed the Ibias only, because IOPC is switched off.

Unit

%

%

Hz

V

V

kHz

ns

ns

mA

V

V

mA

V

ns

ns

V

ns

ms

mV

mV /

ms

kW

−

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