Current-Mode Controller. 1200AP100 Datasheet
Controller for Universal
Off−Line Supplies Featuring
Low Standby Power
Housed in SOIC−8 or PDIP−8 package, the NCP1200A enhances
the previous NCP1200 series by offering a reduced optocoupler
current together with an increased drive capability. Due to its novel
concept, the circuit allows the implementation of complete off−line
AC−DC adapters, battery charger or a SMPS where standby power is a
With an internal structure operating at a fixed 40 kHz, 60 kHz or
100 kHz, the controller supplies itself from the high−voltage rail,
avoiding the need of an auxiliary winding. This feature naturally eases
the designer task in battery charger applications. Finally,
current−mode control provides an excellent audio−susceptibility and
inherent pulse−by−pulse control.
When the current setpoint falls below a given value, e.g. the output
power demand diminishes, the IC automatically enters the so−called
skip cycle mode and provides excellent efficiency at light loads.
Because this occurs at a user adjustable low peak current, no acoustic
noise takes place.
The NCP1200A features an efficient protective circuitry which, in
presence of an overcurrent condition, disables the output pulses while
the device enters a safe burst mode, trying to restart. Once the default
has gone, the device auto−recovers.
• Pb−Free Packages are Available
• No Auxiliary Winding Operation
• Auto−Recovery Internal Output Short−Circuit Protection
• Extremely Low No−Load Standby Power
• Current−Mode Control with Skip−Cycle Capability
• Internal Temperature Shutdown
• Internal Leading Edge Blanking
• 250 mA Peak Current Capability
• Internally Fixed Frequency at 40 kHz, 60 kHz and 100 kHz
• Direct Optocoupler Connection
• SPICE Models Available for TRANsient and AC Analysis
• Pin to Pin Compatible with NCP1200
• AC−DC Adapters for Portable Devices
• Offline Battery Chargers
• Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
CONTROLLER FOR HIGH
POWER AC−DC WALL
ADAPTERS AND OFFLINE
xxx = Specific Device Code
(40, 60 or 100)
y = Specific Device Code
(4 for 40, 6 for 60, 1 for 100)
A = Assembly Location
WL, L = Wafer Lot
Y, YY = Year
W, WW = Work Week
© Semiconductor Components Industries, LLC, 2004
October, 2004− Rev. 5
See detailed ordering and shipping information in the package
dimensions section on page 13 of this data sheet.
1 Publication Order Number:
3 CS VCC 6
*Please refer to the application information section
Figure 1. Typical Application Example
PIN FUNCTION DESCRIPTION
Pin No. Pin Name
Adjust the skipping peak current
2 FB Sets the peak current setpoint
Current sense input
The IC ground
Supplies the IC
8 HV Generates the VCC from the line
This pin lets you adjust the level at which the cycle skipping process takes
place. Shorting this pin to ground, permanently disables the skip cycle
By connecting an optocoupler to this pin, the peak current setpoint is
adjusted accordingly to the output power demand.
This pin senses the primary current and routes it to the internal comparator
via an L.E.B.
The driver’s output to an external MOSFET.
This pin is connected to an external bulk capacitor of typically 10 mF.
This unconnected pin ensures adequate creepage distance.
Connected to the high−voltage rail, this pin injects a constant current into
the VCC bulk capacitor.