Fixed Frequency Current
Mode Controller for Flyback
Converters
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
CC
capacitor by activating
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
NCP12400
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SOIC−7
CASE 751U
MARKING DIAGRAM
8
XXXXX
ALYWG
G
1
•
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
CC
Circuitry
Frequency Modulation for Softened EMI Signature
Adjustable Overpower Protection Dependant on the Mains Voltage
Fault Input for Overvoltage and Over Temperature Protection
V
CC
Operation up to 28 V, with Overvoltage Detection
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
Offline Adapters for Notebooks, LCD, and Printers
Offline Battery Chargers
Consumer Electronic Power Supplies
Auxiliary/Housekeeping Power Supplies
Offline Adapters for Notebooks
400VWXYZf = Specific Device Code
(see page 2)
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
1
8
FAULT
FB
CS
GND
4
(Top View)
5
V
CC
DRV
HV
ORDERING INFORMATION
See detailed ordering and shipping information on page 43 of
this data sheet.
Typical Applications
©
Semiconductor Components Industries, LLC, 2017
October, 2019
−
Rev. 5
1
Publication Order Number:
NCP12400/D
NCP12400
TYPICAL APPLICATION SCHEMATIC
Figure 1. Flyback Converter Application using the NCP12400
Table 1. OPTIONS
OPN
NCP12400BAHAB0DR2G
NCP12400BAHBB0DR2G
NCP12400BBBBB2DR2G
NCP12400BBHAA1DR2G
NCP12400CAHAB0DR2G
NCP12400CBAAB0DR2G
NCP12400CBBAB0DR2G
NCP12400CBHAA0DR2G
NCP12400EAHBB0DR2G
NCP12400BBBBA0DR2G
Brown Out
Start−Stop
103
−
100 V
111
−
103 V
111
−
103 V
111
−
103 V
95
−
93 V
95
−
93 V
95
−
93 V
95
−
93 V
Brown In,
no BO
111
−
103 V
OCP Fault
Latched
Latched
Autorecovery
Autorecovery
Latched
Autorecovery
Autorecovery
Autorecovery
Latched
Autorecovery
Frozen Current
Setpoint
300 mV
300 mV
150 mV
300 mV
300 mV
No
150 mV
300 mV
300 mV
150 mV
Quiet Skip
No, min. 3 pulses only
Yes, min. 3 pulses,
800 Hz burst
Yes, min. 3 pulses,
800 Hz burst
No, min. 3 pulses only
No, min. 3 pulses only
No, min. 3 pulses only
No, min. 3 pulses only
No, min. 3 pulses only
Yes, min. 3 pulses,
800 Hz burst
Yes, min. 3 pulses,
800 Hz burst
Soft Start
4 ms
4 ms
4 ms
10 ms
4 ms
4 ms
4 ms
10 ms
4 ms
10 ms
Frequency
65 kHz
65 kHz
65
→
100 kHz
100 kHz
65 kHz
65 kHz
65 kHz
65 kHz
65 kHz
65 kHz
Table 2. SPECIFIC DEVICE CODE KEY
400
Part
V
BO
A
−
229−211 V
B
−
111−103 V
C
−
95−93 V
D
−
No BO
E
−
Brown In, no BO
W
OCP Fault
A
−
Latched
B
−
Autorecovery
X
Frozen Current
Setpoint
A
−No
B
−
150 mV
C
−
170 mV
D
−
190 mV
E
−
210 mV
F
−
230 mV
G
−
250 mV
H
−
300 mV
Y
Quiet Skip
A
−
No, min. 3
pulses
B
−
Yes, min. 3
pulses,
800 Hz burst
Z
Soft Start
A
−
10 ms
B
−
4 ms
f
Frequency
0
−
65 kHz
1
−
100 kHz
2
−
65
→
100 kHz
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2
NCP12400
Table 3. PIN FUNCTION DESCRIPTION
Pin #
1
Pin Name
FAULT
Function
FAULT Input
Pin Description
Pull the pin up or down to stop the controller. An internal current source allows the
direct connection of an NTC for over temperature detection. Device can restart in
autorecovery mode or can be latched depending on the option.
An optocoupler connected to ground controls the output regulation. The part goes to
the low consumption Off mode if the FB input pin is pulled to GND.
This input senses the primary current for current−mode operation, and offers an
overpower compensation adjustment. This pin implements over voltage protection
as well.
The controller ground.
Drive Output
V
CC
Input
High−Voltage Pin
Drives external MOSFET.
This supply pin accepts up to 28 Vdc, with overvoltage detection. The pin is
connected to an external auxiliary voltage.
Connects to the rectified ac line to perform the functions of start−up current source,
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.
2
3
FB
CS
Feedback + Shutdown
Pin
Current Sense
4
5
6
8
GND
DRV
V
CC
HV
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3
NCP12400
SIMPLIFIED INTERNAL BLOCK SCHEMATIC
Vdd
Vhv DC sample
Brown _In
OVP_CMP
55 us
Filter
Vov p
2. 5V
OVP
AC_Off
HV
Intc
Intc
VccOVP_CMP
OTP_CMP
VccOVP
300 us OTP
Filter
10 us
Filter
26V
OM & X2 & Vcc
Vc cOVP
TSD
Vcc_Int
Vcc regulator
X 2 discharge
11 V regulator
control
Dual HV
start
−up
current source
8 mA
FAULT
Vclamp Rc lamp
1k
VCC
1. 2V
0. 4V
Votp
UVLO_CMP
UVLO
Vc cOFF
IC startB
Vdd reg
SS_end
9.5V
Set
Brown _Out
Rese t
RESET
Q
Qb
Latch
ON_CMP
VccON
Vdd
PowerOnReset _CMP
RESET
Vc cR ESET
VCC
Clamp
Vcc ON
STOP_CMP
VccMIN
VCC
Vc cMI N
10.5V
5uA
Off_mode_CMP1
Set
2.2V
Q
Qb
ICstart
V on
Reset
Off_mode_CMP2
GoToOffMode timer 500ms
0. 6V
jittering
FM input
Square output
Voff
Int ernal resit anc e 40k
Vfb(reg)
OSC 65kHz
ton_max output
3. 0V
freq folback
CSref
FBbuffer
4uMho
Skip _CMP
SkipB
Vsk ip
PFM input
Ramp_OTA
Vramp_of fset
Saw output
FB
Rfb1
1.4V
12V
MAX_ton
PWM_CMP
PWM
IC stopB
Set
Q
7V
Vc c(reg)
10.8V
Vhv DC sample
Div ision rat io 4
Rf b3
R fb2
DRV
Reset
Brown_OutB
Qb
Vf b(opc )
2. 6V
Iopc = 0.5u*(Vhv
−
125)
Vdd
1uA
Soft Start timer
Enable
SS _end
CS
Ilimit_CMP
MAX_ton
Ilimit
Lat chB
Fault B
V to I
LEB 250 ns
SoftStart _CMP
Set
Reset
Q
Qb
Fault timer
Fault
RESET
Latch management
Vfb < 1.64 V fix current setpoint 210mV
Vi lim
0.7V
IC stop
Latch
LEB 120 ns
VC Ss top
CSstop_CMP
4 events timer
1.05V
GND
Brown _Out
TSD
OVP_CMP
600ns timer
1.05V
Vovp
4 events timer
TSD
LEB 1 us
DRV
Figure 2. Simplified Internal Block Schematic
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NCP12400
Table 4. MAXIMUM RATINGS
Rating
DRV
(pin 5)
V
CC
(pin 6)
HV
(pin 8)
V
max
R
qJ−A
Symbol
Maximum voltage on DRV pin
(Dc−Current self−limited if operated within the allowed range) (Note 2)
V
CC
Power Supply voltage, V
CC
pin, continuous voltage
Power Supply voltage, V
CC
pin, continuous voltage (Note 2)
Maximum voltage on HV pin
(Dc−Current self−limited if operated within the allowed range)
Maximum voltage on low power pins (except pin 5, pin 6 and pin 8)
(Dc−Current self−limited if operated within the allowed range) (Note 2)
Thermal Resistance SOIC−7
Junction-to-Air, low conductivity PCB (Note 3)
Junction-to-Air, medium conductivity PCB (Note 4)
Junction-to-Air, high conductivity PCB (Note 5)
Thermal Resistance Junction−to−Case
Operating Junction Temperature
Storage Temperature Range
ESD Capability, HBM model (All pins except HV) (Note 1)
ESD Capability, HBM model (pin 8, HV)
ESD Capability, Charge Discharge Model (Note 1)
Value
–0.3 to 20
±1000
(peak)
–0.3 to 36
±30
(peak)
–0.3 to 500
±20
–0.3 to 5.5
±10
(peak)
162
147
115
73
−40
to +150
−60
to +150
> 4000
> 2000
> 500
Unit
V
mA
V
mA
V
mA
V
mA
°C/W
R
qJ−C
T
JMAX
T
STRGMAX
°C/W
°C
°C
V
V
V
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
2
of 2 oz copper traces and heat spreading area. As specified
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
2
of 2 oz copper traces and heat spreading area. As specified
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
for a JEDEC 51-3 conductivity test PCB. Test conditions were under natural convection or zero air flow.
(For typical values T
J
= 25°C, for min/max values T
J
=
−40°C
to +125°C, V
HV
= 125 V, V
CC
= 11 V unless otherwise noted)
Characteristics
HIGH VOLTAGE CURRENT SOURCE
Minimum voltage for current source
operation
Current flowing out of V
CC
pin
Off−state leakage current
SUPPLY
Turn−on threshold level, V
CC
going up
HV current source stop threshold
(depending on the version)
HV current source restart threshold
Turn−off threshold
Overvoltage threshold
Overvoltage threshold (option EAHBB,
BBBBB)
Blanking duration on V
CC(off)
and V
CC(ovp)
detection
V
CC(on)
11.0
15.0
9.5
8.4
25
30
−
12.0
16.2
10.5
8.9
26.5
32
10
13.0
17.5
11.5
9.3
28
34
−
V
V
CC
= 0 V
V
CC
= V
CC(on)
−
0.5 V
V
HV
= 500 V, V
CC
= 15 V
V
HV(min)
I
start1
I
start2
I
start(off)
−
0.2
5
−
30
0.5
8
2
40
0.8
11
6
V
mA
mA
Test Condition
Symbol
Min
Typ
Max
Unit
Table 5. ELECTRICAL CHARACTERISTICS
V
CC(min)
V
CC(off)
V
CC(ovp)
V
V
V
t
VCC(blank)
ms
6. Guaranteed by design.
7. CS pin source current is a sum of I
bias
and I
OPC
, thus at V
HV
= 125 V is observed the I
bias
only, because I
OPC
is switched off.
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