©
Semiconductor Components Industries, LLC, 2005
July, 2005 − Rev. 3
1
Publication Order Number:
NCP1215/D
NCP1215
Low Cost Variable OFF Time
Switched Mode Power
Supply Controller
The NCP1215 is a controller for low power off−line flyback
Switchemode Power Supplies (SMPS) featuring low size, weight and
cost constraints together with a good low standby power performance.
The operating principle uses switching frequency reduction at light
load by increasing the OFF Time. Also, when OFF Time expands, the
peak current is gradually reduced down to approximately 1/4 of the
maximum peak current to prevent from exciting the transformer
mechanical resonances. The risk of acoustic noise is thus greatly
diminished while keeping good standby power performance.
A low power internal supply block also ensures very low current
consumption at startup without hampering the standby power
performance.
A special primary current sensing technique minimizes the impact
of SMPS switching on control IC operation. The choice of peak
voltage across the current sense resistor allows dissipation to be
further reduced. The negative current sensing technique offers
advantages over a traditional approach by avoiding the voltage drop
incurred by traditional MOSFET source sensing. Thus, the IC drive
capability is greatly improved.
Finally, the bulk input ripple ensures a natural frequency dithering
which smooths the EMI signature.
Features
•
Pb−Free Package is Available
•
Variable OFF Time Control Method
•
Very Low Current Consumption at Startup
•
Natural Frequency Dithering for Improved EMI Signature
•
Current Mode Control Operation
•
Peak Current Compression Reduces Transformer Noise
•
Programmable Current Sense Resistor Peak Voltage
•
Undervoltage Lockout
Typical Applications
•
Auxiliary Power Supply
•
Standby Power Supply
•
AC−DC Adapter
•
Off−line Battery Charger
1
8
SOIC−8
D SUFFIX
CASE 751
1
8
5
3
4
(Top View)
FB
CS
NC
PIN CONNECTIONS
7
6
2
NC
CT
GND
Gate
V
CC
MARKING
DIAGRAMS
FAA
= Specific Device Code
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
1
6
TSOP−6
(SOT23−6, SC59−6)
SN SUFFIX
CASE 318G
FAAYW
1
6
SOIC−8
1
3
FB
CS
2
GND
CT
4
Gate
6
(Top View)
5
V
CC
TSOP−6
ORDERING INFORMATION
P1215
ALYW
Device
Package
Shipping
†
NCP1215DR2
SOIC−8
2500 Tape & Reel
NCP1215SNT1
TSOP−6
3000 Tape & Reel
†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.
1
8
http://onsemi.com
NCP1215DR2G
SOIC−8
(Pb−Free)
2500 Tape & Reel
