NCP1377, NCP1377B
PWM Current−Mode
Controller for Free−Running Quasi−Resonant Operation
The NCP1377 combines a true current mode modulator and a demagnetization detector which ensures full borderline/critical Conduction Mode in any load/line conditions together with minimum drain voltage switching (Quasi−Resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode as soon as the power demand falls below a predetermined level. As this happens at low peak current, no audible noise can be heard. For NCP1377, an internal 8.0 m s timer prevents the free−run frequency to exceed 100 kHz (therefore below the 150 kHz CISPR−22 EMI starting limit), while the skip adjustment capability lets the user select the frequency at which the burst foldback takes place. For NC1377B, the internal timer duration is reduced to 3.0 m s to allow operation at higher frequencies (up to 300 kHz).
The transformer core reset detection is done through an auxiliary winding which, brought via a dedicated pin, also enables fast Over V oltage Protection (OVP). Once an OVP has been detected, the IC permanently latches off. The 1377 features a sampling time of 4.5 m s whereas it is 1.5 m s for the
B version.
The NCP1377 also features an efficient protective circuitries which, in presence of an overcurrent condition, disables the output pulses and enters a safe burst mode, trying to restart. Once the default has gone, the device auto−recovers. Finally an internal 1.0 ms Soft−Start eliminates the traditional startup stress.
Features
•Free−Running Borderline/Critical Mode Quasi−Resonant Operation •Latched Overvoltage Protection
•Auto−Recovery Short−Circuit Protection Via UVLO Crossover •External Latch Triggering, e.g. Via Overtemperature Signal •Current−Mode with Adjustable Skip Cycle Capability •Internal 1.0 ms Soft−Start
•Internal Temperature Shutdown
•Internal Leading Edge Blanking
•500 mA Peak Current Source/Sink Capability
•Under V oltage Lockout Level of 12.5 V (On) and 7.5 V (Min)•Direct Optocoupler Connection
•SPICE Models Available for TRANsient Analysis •Internal Minimum T OFF
•Pb−Free Packages are Available
Typical Applications
•AC−DC Adapters for Notebooks, etc.
•Offline Battery Chargers
•Consumer Electronics (DVD Players, Set−Top Boxes, TVs, etc.)•Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
See detailed ordering and shipping information in the package dimensions section on page 14 of this data sheet.
ORDERING INFORMATION
Figure 1. Typical Application Schematic
PIN FUNCTION DESCRIPTION
Pin Symbol Function Description
1Demag Core reset detection and OVP The auxiliary FLYBACK signal ensures discontinuous operation and offers a fixed
overvoltage detection level of 7.2 V.
2FB Sets the peak current setpoint By connecting an optocoupler to this pin, the peak current setpoint is adjusted
accordingly to the output power demand. By bringing this pin below the internal
skip level, you shut off the device.
3CS Current sense input and skip
cycle level selection This pin senses the primary current and routes it to the internal comparator via an L.E.B. By inserting a resistor in series with the pin, you control the level at which the skip operation takes place.
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−This unconnected pin ensures adequate creepage distance.
8HV High−voltage pin Connected to the high−voltage rail, this pin injects a constant current into the V CC
bulk capacitor and ensures a clean lossless startup sequence.
Figure 2. Internal Circuit Architecture
MAXIMUM RATINGS
Rating Symbol Value Unit Continuous Power Supply or Drive Voltage V CC, Drv18V Transient Power Supply Voltage, Duration < 10 ms, I VCC < 20 mA V CC Pulse25V Maximum Voltage on all other pins except Pin 8 (HV), Pin 6 (V CC) and Pin 5 (Drv)−−0.3 to 10V Maximum Current into all pins except V CC (6), HV (8) and Demag (1) when 10 V ESD
− 5.0mA diodes are activated
Maximum Current in Pin 1Idem+3.0/−2.0mA Thermal Resistance, Junction−to−Case R q JC57°C/W Thermal Resistance, Junction−to−Air, SOIC Version R q JA178°C/W Thermal Resistance, Junction−to−Air, PDIP Version R q JA100°C/W Maximum Junction T emperature TJ MAX150°C
T emperature Shutdown−155°C Hysteresis in Shutdown−30°C Storage T emperature Range−−60 to +150°C ESD Capability, HBM Model (All pins except V CC and HV)− 2.0kV ESD Capability, Machine Model−200V Maximum Voltage on Pin 8 (HV), Pin 6 (V CC) Decoupled to Ground with 10 m F V HV500V 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 = 0°C to +125°C, Max T J = 150°C, V CC = 11 V unless otherwise noted.)
Characteristic Pin Symbol Min Typ Max Unit SUPPL Y SECTION
V CC Increasing Level at which the Current Source Turns−Off6VCC ON11.612.513.7V Minimum Operating Voltage after Turn−On6VCC OFF7.07.58.2V V CC Decreasing Level at which the Latchoff Phase Ends6VCC latch− 5.6−V Internal IC Consumption, No Output Load on Pin 5, F SW= 60 kHz6ICC1− 1.0 1.3
(Note 1)
mA
Internal IC Consumption, 1.0 nF Output Load on Pin 5, F SW= 60 kHz6ICC2− 1.6 2.0
(Note 1)
mA Internal IC Consumption, Latchoff Phase, V CC = 6.0 V6ICC3−220−m A INTERNAL STARTUP CURRENT SOURCE
High−V oltage Current Source, V CC = 10 V, V pin8 = 50 V8IC1 2.4 4.0 6.0mA High−V oltage Current Source, V CC = 0 V, V pin8 = 50 V8IC2− 4.5−mA Startup Leakage, V pin8 = 500 V8I HVLeak−3070m A DRIVE OUTPUT
Output Voltage Rise−Time @ CL = 1.0 nF, 10−90% of Output Signal5T r−40−ns Output Voltage Fall−Time @ CL = 1.0 nF, 10−90% of Output Signal5T f−20−ns Source Resistance5R OH122036W Sink Resistance5R OL 5.01019W CURRENT COMPARATOR
Input Bias Current @ 1.0 V Input Level on Pin 33I IB−0.02−m A Maximum Internal Current Setpoint3I Limit0.9 1.0 1.1V Propagation Delay from Current Detection to Gate OFF State3T DEL−100160ns Leading Edge Blanking Duration3T LEB−380−ns Internal Current Offset Injected on the CS Pin During OFF Time3Iskip−200−m A OVERVOLTAGE SECTION
Sampling Delay After ON Time NCP1377
NCP1377B 1
1
T sample−
−
4.5
1.5
−
−
m s
OVP Internal Reference Level1V ref 6.47.28.0V FEEDBACK SECTION
Internal Pullup Resistor2Rup−20−k W Pin 3 to Current Setpoint Division Ratio−Iratio− 3.3−−Internal Soft−Start−T ss− 1.0−ms DEMAGNETIZA TION DETECTION BLOCK
Input Threshold Voltage (Vpin 1 Decreasing)1V th355090mV Hysteresis (Vpin 1 Decreasing)1V H−20−mV Input Clamp Voltage
High State (Ipin 1 = 3.0 mA) Low State (Ipin 1 = −2.0 mA)1
1
VC H
VC L
8.0
−0.9
10
−0.7
12
−0.5
V
Pin1 Internal Resistance1R int−28−k W Demag Propagation Delay1T dem−210−ns Timeout After Last Demag Transition1T out− 5.0−m s Internal Input Capacitance at Vpin 1 = 1.0 V1C par−10−pF
Minimum T OFF (Internal Blanking Delay After T ON)NCP1377
NCP1377B 1
1
T blank−
−
8.0
3.0
−
−
m s
1.Max value at T j = 0°C, please see characterization curves.
TYPICAL CHARACTERISTICS
−25
0255075100125
TEMPERA TURE (°C)
I l i m i t , (V )
−25
25
50
75
100
125
TEMPERA TURE (°C)
I C 1, (m A )
−25
0255075100125
TEMPERA TURE (°C)
I C C 2, (m A )
−25
0255075100125
TEMPERA TURE (°C)
V C C O F F , (V )
11.0
11.512.012.513.013.514.0−25
0255075100125TEMPERA TURE (°C)7.20
7.307.407.507.607.707.807.900.40
0.600.801.001.201.401.60 1.10
1.30
1.501.701.90
2.102.302.02.5
3.03.5
4.04.5
5.05.5
6.00.90
0.95
1.00
1.051.10
Figure 3. V CCON Threshold versus Temperature
Figure 4. V CCOFF Threshold versus Temperature
Figure 5. Current Consumption (No Load)
versus Temperature
Figure 6. Current Consumption (1.0 nF Load)
versus Temperature
Figure 7. HV Current Source at V CC = 10 V
versus temperature Figure 8. Maximum Current Setpoint versus
Temperature
V C C O N , (V )
−25
0255075100125
TEMPERA TURE (°C)I C C 1, (m A )
TYPICAL CHARACTERISTICS
−25
0255075100125
TEMPERA TURE (°C)
T o u t , (m s )
0.02.04.06.08.010.012.014.016.018.020.00.05.010.015.020.025.030.035.040.0020406080100120 6.46.66.87.07.27.47.67.86.57.07.58.08.59.09.510.0 3.80
4.20
4.60
5.005.405.80
6.206.60
7.00Figure 9. Drive Source Resistance versus
Temperature
Figure 10. Drive Sink Resistance versus
Temperature
Figure 11. Demagnetization Detection Threshold
versus Temperature
Figure 12. OVP Threshold versus Temperature
Figure 13. Minimum T OFF versus Temperature
Figure 14. Demagnetization Detection Timeout
versus Temperature
−25
25
50
75
100
125
TEMPERA TURE (°C)R O H , (W )
−25
25
50
75
100
125
TEMPERA TURE (°C)
R O L , (W )
−25
0255075100125TEMPERA TURE (°C)V T H , (m V )
−25
0255075100125
TEMPERA TURE (°C)
V r e f , (V )
−25
25
50
75
100
125
TEMPERA TURE (°C)T b l a n k , (m s )
