NCP1200
PWM Current-Mode Controller for Low-Power Universal Off-Line Supplies Housed in SOIC−8 or PDIP−8 package, the NCP1200 represents a major leap toward ultra−compact Switchmode Power Supplies. Due to a novel concept, the circuit allows the implementation of a complete offline battery charger or a standby SMPS with few external components. Furthermore, an integrated output short−circuit protection lets the designer build an extremely low−cost AC−DC wall adapter associated with a simplified feedback scheme.
With an internal structure operating at a fixed 40 kHz, 60 kHz or 100 kHz, the controller drives low gate−charge switching devices like an IGBT or a MOSFET thus requiring a very small operating power. Due to current−mode control, the NCP1200 drastically simplifies the
design of reliable and cheap offline converters with extremely low acoustic generation 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 skip cycle mode and provides excellent efficiency at light loads. Because this occurs at low peak current, no acoustic noise takes place.
Finally, the IC is self−supplied from the DC rail, eliminating the need of an auxiliary winding. This feature ensures operation in presence of low output voltage or shorts.
Features
•No Auxiliary Winding Operation
•Internal Output Short−Circuit Protection
•Extremely Low No−Load Standby Power
•Current−Mode with Skip−Cycle Capability
•Internal Leading Edge Blanking
•250 mA Peak Current Source/Sink Capability •Internally Fixed Frequency at 40 kHz, 60 kHz and 100 kHz •Direct Optocoupler Connection
•Built−in Frequency Jittering for Lower EMI
•SPICE Models Available for TRANsient and AC Analysis •Internal Temperature Shutdown
•These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant
Typical Applications
•AC−DC Adapters
•Offline Battery Chargers
•Auxiliary/Ancillary Power Supplies (USB, Appliances, TVs, etc.)
PDIP−8
P SUFFIX
CASE 626
8
SOIC−8
D SUFFIX
CASE 751
18
5
3
4
(Top View)
Adj
CS
HV
PIN CONNECTIONS
7
6
2NC
FB
GND Drv
V CC
MARKING
s1200DIAGRAMS
See detailed ordering and shipping information in the package dimensions section on page 14 of this data sheet.
ORDERING INFORMATION
xxx= Device Code: 40, 60 or 100
y= Device Code:
4 for 40
6 for 60
1 for 100
A= Assembly Location
L= Wafer Lot
Y, YY= Year
W, WW= Work Week
G, G= Pb−Free Package
1200Pxxx
AWL
YYWWG
1
8
onsemi
*Please refer to the application information section
Figure 1. Typical Application
PIN FUNCTION DESCRIPTION
Pin No.Pin Name Function Description
1Adj Adjust the Skipping Peak Current This pin lets you adjust the level at which the cycle skipping process takes
place.
2FB Sets the Peak Current Setpoint By connecting an Optocoupler to this pin, the peak current setpoint is adjus-
ted accordingly to the output power demand.
3CS Current Sense Input This pin senses the primary current and routes it to the internal comparator
via an L.E.B.
4GND The IC Ground
5Drv Driving Pulses The driver’s output to an external MOSFET.
6V CC Supplies the IC This pin is connected to an external bulk capacitor of typically 10 m F.
7NC No Connection This un−connected pin ensures adequate creepage distance.
8HV Generates the V CC from the Line Connected to the high−voltage rail, this pin injects a constant current into
the V CC bulk capacitor.
FB
Drv
V CC
NC
HV
Figure 2. Internal Circuit Architecture
MAXIMUM RATINGS
Rating Symbol Value Units Power Supply Voltage
V CC
16
V
Thermal Resistance Junction −to −Air, PDIP −8 version
Thermal Resistance Junction −to −Air, SOIC version Thermal Resistance Junction −to −Case R q JA R q JA R q JC
10017857°C/W
Maximum Junction Temperature Typical Temperature Shutdown T Jmax −
150140
°C Storage Temperature Range
T stg −60 to +150
°C
ESD Capability, HBM Model (All Pins except V CC and HV)− 2.0
kV ESD Capability, Machine Model
−200V Maximum Voltage on Pin 8 (HV), pin 6 (V CC ) Grounded −450V Maximum Voltage on Pin 8 (HV), Pin 6 (V CC ) Decoupled to Ground with 10 m F
−500V Minimum Operating Voltage on Pin 8 (HV)
−
30
V
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
ELECTRICAL CHARACTERISTICS (For typical values T J = +25°C, for min/max values T J = −25°C to +125°C, Max T J = 150°C,
V CC= 11 V unless otherwise noted)
Rating Pin Symbol Min Typ Max Unit DYNAMIC SELF−SUPPLY (All Frequency Versions, Otherwise Noted)
V CC Increasing Level at Which the Current Source Turns−off6V CCOFF10.311.412.5V V CC Decreasing Level at Which the Current Source Turns−on6V CCON8.89.811V V CC Decreasing Level at Which the Latchoff Phase Ends6V CClatch− 6.3−V Internal IC Consumption, No Output Load on Pin 56I CC1−710880
m A
Note 1
mA Internal IC Consumption, 1 nF Output Load on Pin 5, F SW = 40 kHz6I CC2− 1.2 1.4
Note 2 Internal IC Consumption, 1 nF Output Load on Pin 5, F SW = 60 kHz6I CC2− 1.4 1.6
mA
Note 2
mA Internal IC Consumption, 1 nF Output Load on Pin 5, F SW = 100 kHz6I CC2− 1.9 2.2
Note 2 Internal IC Consumption, Latchoff Phase6I CC3−350−m A INTERNAL CURRENT SOURCE
High−voltage Current Source, V CC = 10 V8I C1 2.8 4.0−mA High−voltage Current Source, V CC = 0 V8I C2− 4.9−mA DRIVE OUTPUT
Output Voltage Rise−time @ CL = 1 nF, 10−90% of Output Signal5T r−67−ns Output Voltage Fall−time @ CL = 1 nF, 10−90% of Output Signal5T f−28−ns Source Resistance (drive = 0, Vgate = V CCHMAX− 1 V)5R OH274061W Sink Resistance (drive = 11 V, Vgate = 1 V)5R OL51225W CURRENT COMPARATOR (Pin 5 Un−loaded)
Input Bias Current @ 1 V Input Level on Pin 33I IB−0.02−m A Maximum internal Current Setpoint3I Limit0.80.9 1.0V Default Internal Current Setpoint for Skip Cycle Operation3I Lskip−350−mV Propagation Delay from Current Detection to Gate OFF State3T DEL−100160ns Leading Edge Blanking Duration3T LEB−230−ns INTERNAL OSCILLATOR (V CC = 11 V, Pin 5 Loaded by 1 k W)
Oscillation Frequency, 40 kHz Version−f OSC364248kHz Oscillation Frequency, 60 kHz Version−f OSC526170kHz Oscillation Frequency, 100 kHz Version−f OSC86103116kHz Built−in Frequency Jittering, F SW = 40 kHz−f jitter−300−Hz/V Built−in Frequency Jittering, F SW = 60 kHz−f jitter−450−Hz/V Built−in Frequency Jittering, F SW = 100 kHz−f jitter−620−Hz/V Maximum Duty Cycl
e−Dmax748087% FEEDBACK SECTION (V CC = 11 V, Pin 5 Loaded by 1 k W)
Internal Pullup Resistor2Rup−8.0−k W Pin 3 to Current Setpoint Division Ratio−Iratio− 4.0−−SKIP CYCLE GENERATION
Default skip mode level1Vskip 1.1 1.4 1.6V Pin 1 internal output impedance1Zout−25−k W
1.Max value @ T J = −25°C.
2.Max value @ T J = 25°C, please see characterization curves.
2.101.901.501.701.30
1.100.9074628056683886929810411011.5011.3011.6011.2011.4011.70750−25
6075305025L E A K A G E (m A )
0TEMPERATURE (°C)
Figure 3. HV Pin Leakage Current vs.
Temperature
Figure 4. V CC OFF vs. Temperature
V C C O F F (V )
9.859.809.759.709.659.609.559.509.45Figure 5. V CC ON vs. Temperature TEMPERATURE (°C)Figure 6. I CC1 vs. Temperature
TEMPERATURE (°C)
I C C 1 (m A )
V C C O N (V )Figure 7. I CC2 vs. Temperature TEMPERATURE (°C)Figure 8. Switching Frequency vs. T J
TEMPERATURE (°C)
I C C 2 (m A )
F S W (k H z )
650800700600850900TEMPERATURE (°C)1020405010012511.10
05044
豫公网安备41160202000603
站长QQ:729038198
关于我们
投诉建议