ON Semiconductor NCP12400 User guide

Fixed Frequency Current

f

Mode Controller for Flyback Converters

NCP12400

The NCP12400 is a new fixed−frequency current−mode controller featuring the Dynamic Self−Supply. This function greatly simplifies the design of the auxiliary supply and the V the internal startup current source to supply the controller during start−up, transients, latch, stand−by etc. This device contains a special HV detector which detects the application unplug from the ac input line and triggers the X2 discharge current. This HV structure allows the brown−out detection as well.

It features a timer−based fault detection that ensures the detection of overload and an adjustable compensation to help keep the maximum power independent of the input voltage.

Due to frequency foldback, the controller exhibits excellent efficiency in light load condition while still achieving very low standby power consumption. Internal frequency jittering, ramp compensation, and a versatile latch input make this controller an excellent candidate for the robust power supply designs.

A dedicated Off Mode allows to reach the extremely low no load input power consumption via “sleeping” whole device and thus minimize the power consumption of the control circuitry.

Features

• Fixed−Frequency Current−Mode Operation 65 kHz or 100 kHz

Frequency Options

• Frequency Foldback then Skip Mode for Maximized Performance

in Light Load and Standby Conditions

• Timer−Based Overload Protection with Latched (Option A) or

Autorecovery (Option B) Operation

• High−Voltage Current Source with Brown−Out Detection and

Dynamic Self−Supply, Simplifying the Design of the V

• Frequency Modulation for Softened EMI Signature

• Adjustable Overpower Protection Dependant on the Mains Voltage

• Fault Input for Overvoltage and Over Temperature Protection

• V

Operation up to 28 V, with Overvoltage Detection

CC

• 300/500 mA Source/Sink Drive Peak Current Capability

• 4/10 ms Soft−Start

• Internal Thermal Shutdown

• No−Load Standby Power < 30 mW

• X2 Capacitor in EMI Filter Discharging Feature

• These are Pb−Free Devices

Typical Applications

• Offline Adapters for Notebooks, LCD, and Printers

• Offline Battery Chargers

• Consumer Electronic Power Supplies

• Auxiliary/Housekeeping Power Supplies

• Offline Adapters for Notebooks

capacitor by activating

CC

Circuitry

CC

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SOIC−7

CASE 751U

MARKING DIAGRAM

8

XXXXX ALYWG

G

1

400VWXYZf

(Note: Microdot may be in either location)

See detailed ordering and shipping information on page 44 o this data sheet.

= Specific Device Code

(see page 2) A = Assembly Location L = Wafer Lot Y = Year W = Work Week G = Pb−Free Package

PIN CONNECTIONS

1

FAULT

FB

CS

GND DRV

4

(Top View)

ORDERING INFORMATION

8

HV

V

CC

5

February, 2021 − Rev. 6

1 Publication Order Number:

NCP12400/D

NCP12400

Table 1. OPTIONS

Part

OPN

Brown Out

OCP Fault

Frozen

Quiet skip

Soft

Frequency

OTP/OVP

NCP12400BAHAB0DR2G

103 − 100 V

Latched

300 mV

No, min. 3 pulses

4 ms

65 kHz

Latched

NCP12400BAHBB0DR2G

111 − 103 V

Latched

300 mV

Yes, min. 3 pulses,

4 ms

65 kHz

Latched

NCP12400BBBBB2DR2G

111 − 103 V

Autorecovery

150 mV

Yes, min. 3 pulses,

4 ms

65 → 100

Latched

NCP12400BBHAA1DR2G

111 − 103 V

Autorecovery

300 mV

No, min. 3 pulses

10 ms

100 kHz

Autorecovery

NCP12400CAHAB0DR2G

95 − 93 V

Latched

300 mV

No, min. 3 pulses

4 ms

65 kHz

Latched

NCP12400CBAAB0DR2G

95 − 93 V

Autorecovery

No

No, min. 3 pulses

4 ms

65 kHz

Latched

NCP12400CBBAB0DR2G

95 − 93 V

Autorecovery

150 mV

No, min. 3 pulses

4 ms

65 kHz

Latched

NCP12400CBHAA0DR2G

95 − 93 V

Autorecovery

300 mV

No, min. 3 pulses

10 ms

65 kHz

Autorecovery

NCP12400EAHBB0DR2G

Brown In, No

Latched

300 mV

Yes, min. 3 pulses,

4 ms

65 kHz

Latched

NCP12400BBBBA0DR2G

111 − 103 V

Autorecovery

150 mV

Yes, min. 3 pulses,

10 ms

65 kHz

Latched

NCP12400BBHAB0DR2

111 − 103 V

Autorecovery

300 mV

No, min. 3 pulses

4 ms

65 kHz

Latched

NCP12400BBEBA0DR2G

111 − 103 V

Autorecovery

210 mV

Yes, min. 3 pulses,

10 ms

65 kHz

Latched

NCP12400BBAAA0DR2G

111 − 103 V

AutorecoveryNoNo

10 ms

65 kHz

Latched

TYPICAL APPLICATION SCHEMATIC

Figure 1. Flyback Converter Application using the NCP12400

NCP12400

Start − Stop

BO

Current

Setpoint

only

800 Hz burst

only

800 Hz burst

only

800 Hz burst

Start

kHz

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2

NCP12400

Table 2. SPECIFIC DEVICE CODE KEY

400VWXYZf

BO

OCP Fault

Frozen Current

Quiet Skip

Soft Start

Frequency

A − 229−211 V

A − Latched

A −No

A − No, min. 3

A − 10 ms

0 − 65 kHz

Table 3. PIN FUNCTION DESCRIPTION

Pin #

Pin Name

Function

Pin Description

1

FAULT

FAULT Input

Pull the pin up or down to stop the controller. An internal current source allows the

2FBFeedback + Shutdown

An optocoupler connected to ground controls the output regulation. The part goes to

3CSCurrent Sense

This input senses the primary current for current−mode operation, and offers an

4

GND

The controller ground.

5

DRV

Drive Output

Drives external MOSFET.

6

VCCVCC Input

This supply pin accepts up to 28 Vdc, with overvoltage detection. The pin is

8HVHigh−Voltage Pin

Connects to the rectified ac line to perform the functions of start−up current source,

Part

B − 111−103 V

C − 95−93 V

D − No BO

E − Brown In, no BO

B − Autorecovery

direct connection of an NTC for over temperature detection. Device can restart in autorecovery mode or can be latched depending on the option.

the low consumption Off mode if the FB input pin is pulled to GND.

overpower compensation adjustment. This pin implements over voltage protection as well.

connected to an external auxiliary voltage.

Setpoint

B − 150 mV C − 170 mV D − 190 mV E − 210 mV

F − 230 mV G − 250 mV H − 300 mV

pulses

B − Yes, min. 3

pulses,

800 Hz burst

B − 4 ms

1 − 100 kHz

2 − 65 → 100 kHz

Self−Supply, brown−out detection and X2 capacitor discharge function and the HV sensing for the overpower protection purposes.

It is not allowed to connect this pin to a dc voltage.

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3

FAULT

FB

CS

GND

Vdd

Intc

1k

Rcla m p

1. 2 V

Vclamp

SS_end

Brown_Out

RESET

VCC

5u A

Von

Vfb(reg)

Voff

Rfb1

Internalresitance40k

Vhv DC sample

V to I

Iopc = 0 .5u*(Vhv −125)

Vdd

1uA

Vfb < 1.64 V fix current setpoint 210mV

OVP_CMP

Vov p

2. 5V OTP_CMP

Votp

0. 4 V

Off_mode_CMP1

2.2V

Off_mode_CMP2

0. 6V

NCP12400

SIMPLIFIED INTERNAL BLOCK SCHEMATIC

300 us

Filter

Vfb(o pc)

Div i sion ratio 4

LEB 250 ns

LEB 120 ns

Latch

Rfb2Rf b3

OVP

OTP

Vskip

Vilim

VCSs to p

LEB 1 us

VccOVP

Set Q

Reset Qb

Skip_CMP

PWM_CMP

SoftStart_CMP

Ilimit_CMP

0.7V

CSstop_CMP

1.05V

10us Filter

ICstart

jittering

freq folback

CSref

SkipB

Soft Start timer

VccMIN

PWM

MAX_ton

Ilimit

OVP_CMP

VccOVP_CMP

UVLO_CMP

UVLO

ON_CMP

VccON

STOP_CMP

FM input

OSC 65kHz

PFM input

Ramp_OTA

4uMho

4 events timer

26V

9.5V

12V10.5 V

Square output

ton_ max output

Saw output

1.4V

Vramp_offset

MAX_ton

Enable SS_end

VccOVP

Vcc_Int

Vdd reg

VccOFF

Vdd

VccONVccMI N

Reset

55us Filter

Set Q

Reset Qb

GoToOffMode timer 500ms

FBbuffer

2. 6V

Bro wn_Ou tB

QSet

Qb

4 events timer600ns timer

IC stopB

FaultB

Vhv DC sample

Brown_In

AC_Off

OM & X2 & Vcc

TSD

X2 discharge

ICstar tB

11V regulator

3. 0V

LatchB

Fault timer

control

PowerOnReset_CMP

Fault

Brown_Out

TSD

Reset

TSD

Dual HV

start−up

current source

Vcc regulator

RESET

QSet

Qb

HV

8mA

VCC

10.8V7V Vcc( reg )VccRESET

VCC

Clamp

DRV

RESET

IC stop Latch

Latch management

Vovp

DRV

1.05V

Figure 2. Simplified Internal Block Schematic

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NCP12400

Table 4. MAXIMUM RATINGS

Rating

Symbol

Value

Unit

DRV

Maximum voltage on DRV pin

–0.3 to 20

V

VCCPower Supply voltage, VCC pin, continuous voltage

–0.3 to 36

VmAHV

Maximum voltage on HV pin

–0.3 to 500

V

Maximum voltage on low power pins (except pin 5, pin 6 and pin 8)

–0.3 to 5.5

V

R

Thermal Resistance SOIC−7

C/W

R

Thermal Resistance Junction−to−Case

73

C/W

T

Operating Junction Temperature

−40 to +150

C

T

Storage Temperature Range

−60 to +150

C

ESD Capability, HBM model (All pins except HV) (Note 1)

> 4000

V

ESD Capability, HBM model (pin 8, HV)

> 2000

V

ESD Capability, Charge Discharge Model (Note 1)

> 500

V

Table 5. ELECTRICAL CHARACTERISTICS

Characteristics

Test Condition

Symbol

Min

Typ

Max

Unit

HIGH VOLTAGE CURRENT SOURCE

Minimum voltage for current source

V

−3040

V

Current flowing out of VCC pin

VCC = 0 V

I

0.250.580.811mA

Off−state leakage current

VHV = 500 V, VCC = 15 V

I

−26

A

SUPPLY

Turn−on threshold level, VCC going up

V

11.0

12.0

13.0

V

HV current source restart threshold

V

9.5

10.5

11.5

V

Turn−off threshold

V

8.4

8.9

9.3

V

Overvoltage threshold

V

253026.5322834V

Blanking duration on V

and V

t

−10−

s

(pin 5)

(pin 6)

(pin 8)

max

q

JMAX

STRGMAX

(Dc−Current self−limited if operated within the allowed range) (Note 2)

CC

Power Supply voltage, VCC pin, continuous voltage (Note 2)

(Dc−Current self−limited if operated within the allowed range)

(Dc−Current self−limited if operated within the allowed range) (Note 2)

J−A

Junction-to-Air, low conductivity PCB (Note 3) Junction-to-Air, medium conductivity PCB (Note 4) Junction-to-Air, high conductivity PCB (Note 5)

J−C

±1000 (peak)

±30 (peak)

±20

±10 (peak)

162 147 115

mA

°

Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected.

1. This device series contains ESD protection and exceeds the following tests: Human Body Model 4000 V per JEDEC standard JESD22, Method A114E Charge Discharge Model Method 500 V per JEDEC standard JESD22, Method C101E

2. This device contains latch-up protection and exceeds 100 mA per JEDEC Standard JESD78.

3. As mounted on a 80 x 100 x 1.5 mm FR4 substrate with a single layer of 50 mm for a JEDEC 51-1 conductivity test PCB. Test conditions were under natural convection or zero air flow.

4. As mounted on a 80 x 100 x 1.5 mm FR4 substrate with a single layer of 100 mm for a JEDEC 51-2 conductivity test PCB. Test conditions were under natural convection or zero air flow.

5. As mounted on a 80 x 100 x 1.5 mm FR4 substrate with a single layer of 650 mm

2

of 2 oz copper traces and heat spreading area. As specified

2

of 2 oz copper traces and heat spreading area. As specified

2

of 2 oz copper traces and heat spreading area. As specified

for a JEDEC 51-3 conductivity test PCB. Test conditions were under natural convection or zero air flow.

(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)

operation

HV current source stop threshold

VCC = V

CC(on)

− 0.5 V

HV(min)

start1

I

start2

start(off)

CC(on)

15.0

16.2

(depending on the version)

CC(min)

CC(off)

Overvoltage threshold (option EAHBB,

CC(ovp)

BBBBB)

detection

CC(off)

CC(ovp)

VCC(blank)

6. Guaranteed by design.

7. CS pin source current is a sum of I

bias

and I

, thus at VHV = 125 V is observed the I

OPC

only, because I

bias

is switched off.

OPC

m

17.5

m

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5

NCP12400

VCC decreasing level at which the internal

V

4.8

7.0

7.7

V

VCC level for I

to I

transition

V

1.0

2.1

3.0

V

Internal current consumption

DRV open, VFB = 3 V, 65 kHz

I

1.0

1.3

2.0

mA

BROWN−OUT

Brown−out thresholds (option A)

VHV going up

V

210

229

248

V

Brown−out thresholds (option B)

VHV going up

V

10294111

120

V

Brown−out thresholds (option BAHAB)

VHV going up

V

9390103

113

V

Brown−out thresholds (option C)

VHV going up

V

87859593103

V

Brown−out thresholds (option E)

VHV going up

V

90

100

110

V

Timer duration for line cycle drop−out

tHV424864738698ms

X2 DISCHARGE

Comparator hysteresis observed at HV pin

V

2.0

3.0

4.0

V

HV signal sampling period

t

−

1.0−ms

Timer duration for no line detection

t

213243

ms

Discharge timer duration

t

213243

ms

Shunt regulator voltage at VCC pin during X2

V

10.0

11.0

12.0

V

OSCILLATOR

Oscillator frequency 65 kHz version

f

619465

69

kHz

Maximum duty−ratio (corresponding to

D

758085

%

Frequency jittering amplitude, in percentage

A

3.0±4.0±5.0

kHz

Frequency jittering modulation frequency

F

85

125

165

Hz

FREQUENCY FOLDBACK

Feedback voltage threshold below which

TJ = 25°C

V

2.4

2.5

2.6

V

Feedback voltage threshold below which

TJ = 25°C

V

2.05

2.15

2.25

V

Minimum switching frequency

VFB = V

+ 0.1

f

252831

kHz

Table 5. ELECTRICAL CHARACTERISTICS

(For typical values T

SUPPLY

logic resets

= 25°C, for min/max values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

J

Characteristics UnitMaxTypMinSymbolTest Condition

START1

START2

Cdrv = 1 nF, V

DRV open, VFB = 3 V, 100 kHz Cdrv = 1 nF, VFB = 3 V, 65 kHz

= 3 V, 100 kHz

FB

Skip or before start−up

Fault mode (fault or latch)

Off−mode

VHV going down

CC(reset)

CC(inhibit)

CC1

I

CC2

I

CC3

I

CC4

I

CC5

HV(start)

V

HV(stop)

HV(start)

V

HV(stop)

HV(start)

V

HV(stop)

HV(start)

V

HV(stop)

HV(start)

1.1

1.5

2.0 400 300

−

194

1.4

2.1

2.6 500 430

25

211

103

100

2.1

2.9

3.4 650 550

−

228

116

110

101

mA mA

mA

mA mA mA

(depending on the version)

discharge event

Oscillator frequency 100 kHz version

maximum on time at maximum switching frequency)

of F

OSC

frequency foldback starts

frequency foldback is complete

HV(hyst)

sample

DET

DIS

CC(dis)

OSC

MAX

jitter

FB(foldS)

FB(foldE)

100

110

±

6. Guaranteed by design.

7. CS pin source current is a sum of I

bias

and I

skip(in)

, thus at VHV = 125 V is observed the I

OPC

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6

OSC(min)

only, because I

bias

is switched off.

OPC

NCP12400

OUTPUT DRIVER

Rise time, 10 to 90% of V

VCC = V

+ 0.2 V,

t

−4070

ns

Fall time, 90 to 10% of V

VCC = V

+ 0.2 V,

t

−3060

ns

Current capability

VCC = V

+ 0.2 V,

mA

Clamping voltage (maximum gate voltage)

VCC = V

– 0.2 V, DRV high,

V

101214

V

High−state voltage drop

VCC = V

+ 0.2 V,

V

−−1

V

CURRENT SENSE

Input Pull−up Current

VCS = 0.7 V

I

−1−

A

Maximum internal current setpoint

VFB > 3.5 V

V

0.66

0.70

0.74

V

Propagation delay from V

detection to

VCS = V

t

−5070

ns

Leading Edge Blanking Duration for V

t

180

250

320

ns

Threshold for immediate fault protection

V

0.95

1.05

1.15

V

Leading Edge Blanking Duration for V

)

t

75

120

150

ns

Soft−start duration (option A)

From 1st pulse to VCS = V

t

−

10

13

ms

Frozen current setpoint (option B)

V

100

150

200

mV

Over voltage protection threshold when DRV

VCS going up

V

1.00

1.05

1.10

V

Blanking duration on OVP detection

t

0.7

1.0

1.3

s

Delay time constant before OTP confirmation

t

−

600−ns

INTERNAL SLOPE COMPENSATION

Slope of the compensation ramp

S

−−−32.5

−−mV /

FEEDBACK

Internal pull−up resistor

TJ = 25°C

R

304050

k

VFB to internal current setpoint division ratio

KFB−4−

−

Internal pull−up voltage on the FB pin

V

4.555.5

V

Offset between FB pin and internal FB

TJ = 25°C

V

−

0.8−V

SKIP CYCLE MODE

Feedback voltage thresholds for skip mode

VFB going down, TJ = 25°C

V

0.9

1.0

1.1

V

Minimum number of pulses in burst

n

3−−

Skip out delay

t

−−38

s

Table 5. ELECTRICAL CHARACTERISTICS

(For typical values T

DRV off

activation

= 25°C, for min/max values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

J

Characteristics UnitMaxTypMinSymbolTest Condition

CC

Ilimit

ILIM

C

C DRV high, V DRV low, V

CC(ovp)

R

= 33 kW, C

DRV

R

= 33 kW, DRV high

DRV

CC(off)

DRV

CC(off)

DRV

CC(off)

DRV

CC(min)

= 1 nF

DRV

load

ILIM

= 0 V

= V

CC

= 220 pF

rise

fall

I

DRV(source)

I

DRV(sink)

DRV(clamp)

DRV(drop)

bias

ILIM

delay

LEB

CS(stop)

−

300 500

−

m

(Note 6)

Soft−start duration (option B)

Frozen current setpoint (option D) Frozen current setpoint (option E) Frozen current setpoint (option H)

is low

(Note 6)

divider

CS(stop

ILIM

BCS

SSTART

I(freeze)

OVP(CS)

OVP,CS OVP,del

comp(65kHz)

S

comp(100kHz)

FB(up)

FB(ref) FB(off)

3.2

140 145 250

4.0

190 210 300

−50

4.8

240 270 350

m

ms

W

6. Guaranteed by design.

7. CS pin source current is a sum of I

skip(in)

V

skip(out)

P,skip

skip

only, because I

bias

1.05

1.15

is switched off.

OPC

1.25

m

bias

and I

VFB going up, TJ = 25°C

, thus at VHV = 125 V is observed the I

OPC

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NCP12400

REMOTE CONTROL ON FB PIN

The voltage above which the part enters the

VCC > V

, VHV = 60 V

VON−

2.2−V

The voltage below which the part enters the

VCC > V

V

0.5

0.6

0.7

V

Minimum hysteresis between the VON and

VCC > V

, VHV = 60 V

V

500−−

mV

Pull−up current in off mode

VCC > V

I

−5−

A

Go To Off mode timer

VCC > V

t

400

500

600

ms

OVERLOAD PROTECTION

Fault timer duration

t

108

128

178

ms

Fault timer reset time

VCS < 0.7 V, D < 90% D

t

150

200

250

s

Autorecovery mode latch−off time duration

t

0.85

1.00

1.35

s

OVERPOWER PROTECTION

VHV to I

conversion ratio

K

−

0.54

−

A / V

Current flowing out of CS pin (Note 7)

VHV = 125 V

I

−

0

−

A

FB voltage above which I

is applied

VHV = 365 V

V

−

2.6−V

FB voltage below which is no I

applied

VHV = 365 V

V

−

1.6−V

FAULT INPUT

High threshold

V

going up

V

2.43

2.50

2.57

V

Low threshold

V

going down, TJ = 25°C

V

0.380

0.400

0.420

V

OTP resistance threshold (TJ = 25°C)

External NTC resistance is going

R

7.6

8.0

8.5

k

OTP resistance threshold (TJ = 80°C)

External NTC resistance is going

R

−

8.5

−

k

OTP resistance threshold (TJ = 110°C)

External NTC resistance is going

R

−

9.5

−

k

Current source for direct NTC connection

V

= 0.2 V

A

Current source for direct NTC connection

V

= 0.2 V, TJ = 25°C

I

475053

A

Blanking duration on high latch detection

t

355070

s

Blanking duration on low latch detection

t

−

350

−

s

Clamping voltage

I

= 0 mA

V

1.0

1.2

1.4

V

TEMPERATURE SHUTDOWN

Temperature shutdown

TJ going up

T

−

150

−°C

Temperature shutdown hysteresis

TJ going down

T

−30−°C

6. Guaranteed by design.

Table 5. ELECTRICAL CHARACTERISTICS

(For typical values T

on mode

off mode

V

OFF

OPC

= 25°C, for min/max values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

J

Characteristics UnitMaxTypMinSymbolTest Condition

OPC

CC(off)

CC(off) CC(off)

VHV = 162 V

= 325 V

V

HV

V

= 365 V

HV

MAX

OFF

HYST

OFF

GTOM

fault

fault,res

autorec

OPC

OPC(125)

I

OPC(162)

I

OPC(325)

I

OPC(365)

FB(OPCF)

FB(OPCE)

−

105

20 110 130

m

−

150

During normal operation During soft−start

During normal operation

7. CS pin source current is a sum of I

bias

and I

Latch

down

Latch

I

= 1 mA

Latch

, thus at VHV = 125 V is observed the I

OPC

OVP OTP OTP

OTP

I

NTC

I

NTC(SSTART)

NTC

Latch(OVP) Latch(OTP)

clamp0(Latch)

V

clamp1(Latch)

TSD

TSD(HYS)

only, because I

bias

30 60

1.8

50 100

2.4

is switched off.

OPC

W

m

70

140

m

3.0

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions.

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8

NCP12400

TYPICAL CHARACTERISTIC

Figure 3. Minimum Voltage for HV Current Source

Operation V

HV(min)

Figure 5. HV Pin Device Startup Threshold

V

HV(start)

Figure 4. High Voltage Startup Current Flowing

Out of V

CC

Pin I

of VCC Pin Fault/Short

start1

Figure 6. Off−state Leakage Current from HV Pin

I

start(off)

Figure 7. High Voltage Startup Current Flowing

Out of V

CC

Pin I

start2

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Figure 8. HV Pin Device Stop Threshold V

9

HV(stop)

NCP12400

Figure 9. Maximum Internal Current Setpoint

V

ILIM

Figure 11. Propagation Delay t

delay

Figure 10. Threshold for the Very Fast Fault

Protection Activation V

Figure 12. Frozen Current Setpoint V

CS(stop)

I(freeze)

Light Load Operation

for the

Figure 13. Over Voltage Protection Threshold at

CS Pin V

OVP(CS)

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Figure 14. Leading Edge Blanking Duration t

LEB

NCP12400

Figure 15. FB Pin Internal Pull−up Resistor

R

FB(up)

Figure 17. FB Pin Skip−In and Skip−Out Levels

V

skip(in)

and V

skip(out)

Figure 16. Built in Offset between FB Pin and

Internal Divider V

Figure 18. FB Pin Open Voltage V

FB(off)

FB(ref)

Figure 19. FB Pin Frequency Foldback Thresholds

V

FB(foldS)

and V

FB(foldE)

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11

NCP12400

Figure 20. Oscillator Switching Frequency f

OSC

Figure 22. X2 Discharge Comparator Hysteresis

Observed at HV Pin V

HV(hyst)

Figure 21. Minimum Switching Frequency

f

OSC(min)

Figure 23. Maximum Duty Cycle D

MAX

Figure 24. The Fault Timer Duration t

fault

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Figure 25. HV Signal Sampling Period T

sample

NCP12400

Figure 26. VCC T urn−on Threshold Level, VCC Going

Up HV Current Source Stop Threshold V

CC(on)

Figure 28. Internal Current Consumption when

DRV Pin is Unloaded I

CC1

Figure 27. VCC Turn−off Threshold (UVLO) V

CC(off)

Figure 29. HV Current Source Restart Threshold

V

CC(min)

Figure 30. VCC Decreasing Level at which the

Internal Logic Resets V

CC(reset)

Figure 31. Internal Current Consumption when

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13

DRV Pin is Loaded by 1 nF Capacitance I

CC2

NCP12400

Figure 32. Internal Current Consumption in Skip

Mode I

CC3

Figure 34. Go To Off Mode Timer Duration t

GTOM

Figure 33. FB Pin Voltage Level Above which is

Entered Normal Operating Mode V

ON

Figure 35. Internal Current Consumption in Off

Mode I

CC5

Figure 36. FB Pin Voltage Level Below which is

Entered Off Mode V

OFF

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14

NCP12400

Figure 37. FB Pin Voltage Thresholds for

Overpower Compensation

Figure 39. Current I

Sourced Out from the

NTC

Fault Pin, allowing Direct NTC Connection

Figure 38. Fault Pin High Threshold for OVP V

Figure 40. Current Flowing Out from CS Pin for

Over Power Compensation @ 365 V at HV Pin

I

OPC(365)

OVP

Figure 41. Fault Pin Low Threshold for OTP V

OTP

NOTE: The OTP resistance maximum and minimum courses are not the guaranteed limits, but the maximum and minimum measured data values from the device characterization.

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15

Figure 42. The OTP Resistance Threshold R

OTP