NCP1215A Datasheet, PDF (1/16 Pages) ON Semiconductor – Low Cost Variable OFF Time Switched Mode Power Supply Controller

NCP1215A
Low Cost Variable OFF
Time Switched Mode Power
Supply Controller
The NCP1215A is a controller for low power off−line flyback
Switched Mode 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
• 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
• Pb−Free Packages are Available
Typical Applications
• Auxiliary Power Supply
• Standby Power Supply
• AC−DC Adapter
• Off−line Battery Charger
© Semiconductor Components Industries, LLC, 2005
1
September, 2005 − Rev. 2
http://onsemi.com
MARKING
DIAGRAM
8
1
SOIC−8
D SUFFIX
CASE 751
8
1215A
ALYW
G
1
TSOP−6
6
6
(SOT23−6, SC59−6)
SN SUFFIX
FACAYW G
G
1
CASE 318G
1
FAC = Specific Device Code
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
SOIC−8
FB 1
8 NC
CT 2
7 NC
CS 3
GND 4
6 V_CC
5 Gate
(Top View)
TSOP−6
CS 1
6 Gate
GND 2
CT 3
5 V_CC
4 FB
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 3 of this data sheet.
Publication Order Number:
NCP1215A/D