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NCP1205
Single Ended PWM
Controller Featuring QR
Operation and Soft
Frequency Foldback
The NCP1205 combines a true Current Mode Control modulator
and a demagnetization detector to ensure full Discontinuous
Conduction Mode in any load/line conditions and minimum drain
voltage switching (Quasi−Resonant operation, also called critical
conduction operation). With its inherent Variable Frequency Mode
(VFM), the controller decreases its operating frequency at constant
peak current whenever the output power demand diminishes.
Associated with automatic multiple valley switching, this unique
architecture guarantees minimum switching losses and the lowest
power drawn from the mains when operating at no−load conditions.
Thus, the NCP1205 is optimal for applications targeting the newest
International Energy Agency (IEA) recommendations for standby
power.
The internal High−Voltage current source provides a reliable
charging path for the V
CC
capacitor and ensures a clean and short
startup sequence without deteriorating the efficiency once off.
The continuous feedback signal monitoring implemented with an
Overcurrent fault Protection circuitry (OCP) makes the final design
rugged and reliable. The PDIP−14 offers an adjustable version of the
OVP threshold via an external resistive network.
Features
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MARKING
DIAGRAM
8
PDIP−8
N SUFFIX
CASE 626
1
1
14
14
1
PDIP−14
P SUFFIX
CASE 646
1
16
16
1
SOIC−16
D SUFFIX
CASE 751B
1
A
WL
YY, Y
WW
G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
NCP1205DG
AWLYWW
NCP1205P2
AWLYYWWG
1205P
AWL
YYWWG
8
•
Natural Drain Valley Switching for Lower EMI and Quasi−Resonant
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Operation (QR)
Smooth Frequency Foldback for Low Standby and Minimum Ripple
at Light−Load
Adjustable Maximum Switching Frequency
Internal 200 ns Leading Edge Blanking on Current Sense
250 mA Sink and Source Driver
Wide Operating Voltages: 8.0 to 30 V
Wide UVLO Levels: 7.2 to 15 V Typical
Auto−Recovery Internal Short−Circuit Protection (OCP)
Integrated 3.0 mA Typ Startup Source
Current Mode Control
Adjustable Overvoltage Level
Pb−Free Packages are Available*
High Power AC/DC Adapters for Notebooks, etc.
Offline Battery Chargers
Power Supplies for DVD, CD Players, TVs, Set−Top Boxes, etc.
Auxiliary Power Supplies (USB, Appliances, etc.)
ORDERING INFORMATION
Device
NCP1205P
NCP1205PG
NCP1205P2
NCP1205P2G
NCP1205DR2
NCP1205DR2G
Package
PDIP−8
PDIP−8
(Pb−Free)
PDIP−14
PDIP−14
(Pb−Free)
SOIC−16
SOIC−16
(Pb−Free)
Shipping
†
50 Units/Rail
50 Units/Rail
25 Units/Rail
25 Units/Rail
2500/Tape & Reel
2500/Tape & Reel
Applications
*For additional information on our Pb−Free strategy and soldering details, please
download the ON Semiconductor Soldering and Mounting Techniques
Reference Manual, SOLDERRM/D.
©
Semiconductor Components Industries, LLC, 2006
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
Publication Order Number:
NCP1205/D
October, 2006
−
Rev. 7
1
NCP1205
PIN CONNECTIONS
HV
HV 1
NC 2
Demag 3
HV 1
Demag 2
FB 3
Ct 4
PDIP−8
8 V
CC
7 Drive
6 Isense
5 GND
FB 4
Ct 5
OVP 6
NC 7
PDIP−14
14 NC
13 V
CC
12 Drive
11 Isense
10 GND
9 NC
8 NC
NC
NC
Demag
FB
Ct
OVP
NC
1
2
3
4
5
6
7
8
SOIC−16
16 NC
15 NC
14 V
CC
13 Drive
12 Isense
11 GND
10 NC
9 NC
PIN FUNCTION DESCRIPTION
Pin No.
PDIP−8
1
2
3
4
5
NA
6
7
8
PDIP−14
1
3
4
5
10
6
11
12
13
SOIC−16
1
4
5
6
11
7
12
13
14
Pin Name
HV
Demag
FB
Ct
GND
OVP
Isense
Drv
V
CC
Function
Startup rail
Zero primary−current
detection
Feedback signal to
control the PWM
Timing capacitor
The IC’s ground
Overvoltage input
The primary−current
sensing pin
This pin drives the
external switcher
Powers the IC
Description
Connected to the rectified HV rail, this pin provides a
charging path to V
CC
bulk capacitor.
This pin ensures the restart of the main switcher when
operating in free−run.
This level modulates the peak current level in free−running
operation and modulates the frequency in VFM operation.
By adding a capacitor from Ct to the ground, the user selects
the minimum/maximum operating frequency.
−
By applying a 2.8 V typical level on this pin, the IC is
permanently latched−off until V
CC
falls below UVLO
L
.
This pin senses the primary current via an external shunt
resistor.
The IC is able to deliver or absorb 250 mA peak currents
while delivering a clamped driving signal.
A positive voltage up to 30 V maximum can be applied upon
this pin before the IC stops.
1. PDIP−14 has different pinouts. Please see Pin Connections.
2. Pin 2, 7, 8, 9 and 14 are nonconnected on PDIP−14.
3. Pin 2, 3, 8, 9, 10, 15 and 16 are nonconnected on SOIC−16.
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2
NCP1205
R2
150
+
C1
10
mF
4x1N4007
+
C14
22
mF
D2
1N4148
D6
1N5819
C10
470
mF
10 V
+
L2
10
mH
5V
+
C11
100
mF
10 V
R5
15
R8
22 k
* R10
15 k
M2
MTD1N60E
1
2
4
8
7
5
R4
10
IC4
D7
5.1 V
Universal Input
3
NCP1205P
6
SFH6156−2
R6
4.7 k
C12
1 nF
R3
3.3
R1
560
C13
1.5 nF Y1
* Please refer to the application information section regarding this element.
Figure 1. Typical Application Example for PDIP−8 Version
+ C1
10
mF
R2
15
D2
1N4148
R5
15
R8
22 k
1
2
Universal Input
3
4
5
6
7
R6
2.7 k
ROVPU
4x1N4007
* R10
15 k
+
C14
33
mF/35
V
D6
1N5819
C10
470
mF
10 V
+
L2
10
mH
5V
+
C11
47
mF
10 V
D7
4.3 V
NCP1205P2
14
13
12
11
10
9
8
SFH6156−2
M2
MTD1N60E
R4
6.8
IC4
R1
560
ROVPL
C12
1 nF
R3
3.3
* Please refer to the application information section regarding this element.
Figure 2. Typical Application Example for PDIP−14 Version
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3
NCP1205
Startup
UVLO
H
= 15 V
UVLO
L
= 7.2 V
Internal V
CC
Internal Regulator
7 DRV
Internal Clamp
V
err
Max = 3 V
V
err
Min = 10 mV
1/3
250 mV
−
1 V
Max Setpoint
Clock
R Flip−Flop Q
D
2.5 V
Current Comparator
−
+
5 GND
200 ns L.E.B
1V
V
err
V
CO
Feedback
T
off
= f (V
err
)
Max T
off
= f (Ct)
OVP
−
+
Driver
6 I
sense
HV 1
Last Pulse of Demag
after 4
ms
8 V
CC
Demag 2
DEMAG ?
Rf
−
+
+
−
Ri
FB 3
Ct 4
Over Current
Protection (OCP)
V(−) < 1.5 V
+
−
Lasts more than 128 ms?
−−>
Protection Circuitry
250 mV Clamp
18 k
+
−
2.8 V
Figure 3. Internal Circuit Architecture for PDIP−8 Version
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4
Mobile and portable
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