NCP1236 View Datasheet(PDF) - ON Semiconductor

Part Name

Description

Manufacturer

NCP1236

Fixed Frequency Current Mode Controller for Flyback Converters

ON Semiconductor 

NCP1236

SIMPLIFIED INTERNAL BLOCK SCHEMATIC

VDD

Brown−out

BO

+

blanking

INTC

+

−

tLatch(OVP)

HV sample

HV dc

INTC

VOVP

VCC OVP

HV

Latch

1 kW

Vclamp

−

+

+

VOTP

blanking

tLatch(OTP)

Soft−start

end

Brown−out

Reset

TSD

S

Q

Latch

R

Reset

UVLO

VDD

IC Start

VCC OVP

TSD

Dual HV

start−up

current source

TSD HV current

Reset

UVLO

VDD

Start

VCC

management

OVP

VFB(ref)

20 kW

−

+

+

Vskip

VCC

/5

slope

FB

comp.

HV sample

V to I

IOPC = 0.5m x

(VHV − 125)

VFB(OPC)

blanking

tLEB

CS

blanking

tBCS

PWM

+

−

Jitter

Soft−start

+

−

Soft−start ramp Start

End tSSTART Reset

IC Start

IC Stop

Soft−start end

+

+

−

VILIM

ILIMIT

IC stop

Sawtooth

Stop Foldback

Oscillator

DMAX

DCMAX

S

Q

R

Clamp

ILIMIT

DMAX

S

Fault Flag

Q

R

PWM

UVLO

+

+

−

VCS(stop)

tfault timer

Fault

Brown−out

Reset

Protection

Mode

release

For

Autorecovery

protection

mode only

timer

tautorec

Brown−out

Latch

TSD

Figure 2. Simplified Internal Block Schematic

http://onsemi.com

3

DRV

GND

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