NCP1271
Soft-Skip Mode PWM ControllerThe NCP1271 is a soft-skip mode pwm controller from onsemi. View the full NCP1271 datasheet below including key specifications, absolute maximum ratings.
Official NCP1271 datasheet (PDF) — the source this page was extracted from.
Manufacturer
onsemiCategory
Power ManagementNCP1271 Key Specifications
| Parameter | Value |
|---|---|
| Fault Timer | 130 ms |
| Standby Power | 83 mW at 230 Vac (application circuit) |
| Latch Threshold | 8.0 V typ |
| Frequency Jitter | ±7.5% at 6.0 ms period |
| HV Pin Max Voltage | 500 V |
| Maximum Duty Cycle | 80% typ (75% to 85%) |
| Soft-Start Duration | 4.0 ms |
| VCC Operating Range | 10 V to 20 V |
| Leading Edge Blanking | 180 ns typ |
| Oscillation Frequency | 65 kHz or 100 kHz versions |
| Default Skip Threshold | 1.2 V |
| Startup Current Source | 4.1 mA typ |
| Current Sense Threshold | 1.0 V ±5% |
| Gate Drive Peak Current | +500 mA / -800 mA |
| VCC Startup Threshold (Typ) | 12.6 V |
| Operating Junction Temperature | -40°C to 150°C |
| VCC Minimum Operating Voltage After Turn-On (Typ) | 9.1 V |
NCP1271 Overview
Part: NCP1271 — onsemi
Type: Fixed-Frequency Current-Mode PWM Flyback Controller with Soft-Skip Mode
Description: Current-mode PWM controller with 65 kHz or 100 kHz fixed frequency options, integrated 500 V high-voltage startup current source, adjustable skip level, external latch input, and +500 mA/-800 mA peak gate drive.
Operating Conditions:
- Supply voltage (VCC): 10–20 V operating range (UVLO start threshold 12.6 V typ)
- Operating junction temperature: -40 to +125 °C (electrical characteristics min/max range)
- Switching frequency: 65 kHz (A version) or 100 kHz (B version)
Absolute Maximum Ratings:
- VCC pin max voltage: -0.3 to +20 V (max current 100 mA)
- Skip/Latch, FB, CS pins: -0.3 to +10 V (max current 100 mA)
- Drv pin voltage: -0.3 to +20 V
- HV pin max voltage: -0.3 to +500 V
- Drv peak current: -800 to +500 mA
- Operating junction temperature range: -40 to +150 °C
- Storage temperature range: -60 to +150 °C
Key Specs:
- Oscillation frequency (65 kHz version): 65 kHz typ, 61.75–68.25 kHz at TJ = 25 °C
- Oscillation frequency (100 kHz version): 100 kHz typ, 95–105 kHz at TJ = 25 °C
- Frequency jitter: ±7.5% at 6.0 ms period
- Maximum duty cycle: 80% typ (75–85%)
- Current limit threshold: 1.0 V typ (0.95–1.05 V)
- Leading edge blanking: 180 ns typ (100–330 ns)
- Gate drive resistance: 11 Ω typ high, 6.0 Ω typ low (VCC = 14 V)
- Gate rise/fall time: 30 ns / 20 ns typ (1 nF load)
- Startup/shutdown thresholds: VCC(on) 12.6 V typ, VCC(off) 9.1 V typ
- Operating supply current: 2.3 mA typ (65 kHz), 3.1 mA typ (100 kHz) at VCC = 14 V, 1 nF load
- HV startup current: 4.1 mA typ (3.0–6.0 mA)
- Default skip threshold: 1.2 V typ
- Latch threshold: 8.0 V typ (7.1–8.7 V)
- Fault validation time: 130 ms typ
- Soft-start duration: 4.0 ms typ
Features:
- Fixed-frequency current-mode operation with ramp compensation and skip cycle in standby
- Timer-based fault protection for improved overload detection
- Soft-Skip mode for optimal noise control in standby
- Internal high-voltage startup current source
- ±5% current limit accuracy over the full temperature range
- Adjustable skip level
- Internal latch for overvoltage and overtemperature protection
- Frequency jittering for softened EMI signature
- +500 mA/-800 mA peak current drive capability
- Sub-100 mW standby power achievable
- Pin-to-pin compatible with the NCP120X series
- Pb-free device
Applications:
- AC-DC adapters for notebooks and LCD monitors
- Offline battery chargers
- Consumer electronics appliances (STB, DVD, DVDR)
Package:
- PDIP-7
- SO-7
NCP1271 Features
- Fixed -Frequency Current -Mode Operation with Ramp Compensation and Skip Cycle in Standby Condition
- Timer -Based Fault Protection for Improved Overload Detection
- 'Soft -Skip Mode' Technique for Optimal Noise Control in Standby
- Internal High -Voltage Startup Current Source for Lossless Startup
- " 5% Current Limit Accuracy over the Full Temperature Range
- Adjustable Skip Level
- Internal Latch for Easy Implementation of Overvoltage and Overtemperature Protection
- Frequency Jittering for Softened EMI Signature
- +500 mA/ -800 mA Peak Current Drive Capability
- Sub -100 mW Standby Power can be Achieved
- Pin -to -Pin Compatible with the Existing NCP120X Series
- This is a Pb -Free Device
NCP1271 Applications
- AC -DC Adapters for Notebooks, LCD Monitors
- Offline Battery Chargers
- Consumer Electronic Appliances STB, DVD, DVDR
1
NCP1271 Pin Configuration
| Pin No. | Symbol | Function | Description |
|---|---|---|---|
| 1 | Skip/latch | Skip Adjust or Latchoff | A resistor to ground provides the adjustable standby skip level. Additionally, if this pin is pulled higher than 8.0 V (typical), the controller latches off the drive. |
| 2 | FB | Feedback | An optocoupler collector pulls this pin low during regulation. If this voltage is less than the Skip pin voltage, then the driver is pulled low and Soft - Skip mode is activated. If this pin is open (>3 V) for more than 130 ms, then the controller is placed in a fault mode. |
| 3 | CS | Current Sense | This pin senses the primary current for PWMregulation. The maximum primary current is limited to 1.0 V / R CS where R CS is the current sense resistor. Additionally, a ramp resistor R ramp between the current sense node and this pin sets the compensation ramp for im- proved stability. |
| 4 | Gnd | IC Ground | - |
| 5 | Drv | Driver Output | The NCP1271's powerful output is capable of driving the gates of large Qg MOSFETs. |
| 6 | V CC | Supply Voltage | This is the positive supply of the device. The operating range is between 10 V (min) and 20 V (max) with a UVLO start threshold 12.6 V (typ). |
| 8 | HV | High Voltage | This pin provides (1) Lossless startup sequence (2) Double hiccup fault mode (3) Memory for latch - off shutdown and (4) Device protection if V CC is shorted to GND. |
Figure 2. Functional Block Diagram
ELECTRICAL CHARACTERISTICS (For typical values T J = 25 C, for min/max values, T J = -40 C to +125 C, V CC = 14 V, HV = open, skip = open, FB = 2 V, CS = Ground, DRV = 1 nF, unless otherwise noted.)
| Characteristic | Pin | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| OSCILLATOR | ||||||
| Oscillation Frequency (65 kHz Version, T J = 25 _ C) Oscillation Frequency (65 kHz Version, T J = - 40 to + 85 _ C) Oscillation Frequency (65 kHz Version, T J = - 40 to + 125 _ C) Oscillation Frequency (100 kHz Version, T J = 25 _ C) Oscillation Frequency (100 kHz Version, T J = - 40 to +85 _ C) Oscillation Frequency (100 kHz Version, T = - 40 to +125 _ C) | 5 | f osc | 61.75 58 55 95 89 85 | 65 65 65 100 100 100 | 68.25 69 69 105 107 107 | kHz |
| Oscillator Modulation Swing, in Percentage of f osc | 5 | - | - | " 7.5 | - | % |
| Oscillator Modulation Swing Period | 5 | - | - | 6.0 | - | ms |
| Maximum Duty Cycle (V CS = 0 V, V FB = 2.0 V) | 5 | D max | 75 | 80 | 85 | % |
| GATE DRIVE | ||||||
| Gate Drive Resistance Output High (V CC = 14 V, Drv = 300 W to Gnd) Output Low (V CC = 14 V, Drv = 1.0 V) | 5 | R OH R OL | 6.0 2.0 | 11 6.0 | 20 12 | W |
| Rise Time from 10% to 90% (Drv = 1.0 nF to Gnd) | 5 | t r | - | 30 | - | ns |
| Fall Time from 90% to 10% (Drv = 1.0 nF to Gnd) | 5 | t f | - | 20 | - | ns |
| CURRENT SENSE | ||||||
| Maximum Current Threshold | 3 | I Limit | 0.95 | 1.0 | 1.05 | V |
| Soft - Start Duration | - | t SS | - | 4.0 | - | ms |
| Soft - Skip Duration | - | t SK | - | 300 | - | m s |
| Leading Edge Blanking Duration | 3 | t LEB | 100 | 180 | 330 | ns |
| Propagation Delay (Drv =1.0 nF to Gnd) | - | - | - | 50 | 150 | ns |
| Ramp Current Source Peak | 3 | I ramp(H) | - | 100 | - | m A |
| Ramp Current Source Valley | 3 | I ramp(L) | - | 0 | - | m A |
| SKIP | ||||||
| Default Standby Skip Threshold (Pin 1 = Open) | 2 | V skip | - | 1.2 | - | V |
| Skip Current (Pin 1 = 0 V, T J = 25 _ C) | 1 | I skip | 26 | 43 | 56 | m A |
| Skip Level Reset (Note 5) | 1 | V skip - reset | 5.0 | 5.7 | 6.5 | V |
| Transient Load Detection Level to Disable Soft - Skip Mode | 2 | V TLD | 2.6 | 2.85 | 3.15 | V |
| EXTERNAL LATCH | ||||||
| Latch Protection Threshold | 1 | V latch | 7.1 | 8.0 | 8.7 | V |
| Latch Threshold Margin (V latch - m = V CC(off) - V latch ) | 1 | V latch - m | 0.6 | 1.2 | - | V |
| Noise Filtering Duration | 1 | - | - | 13 | - | m s |
| Propagation Delay (Drv = 1.0 nF to Gnd) | 1 | T latch | - | 100 | - | ns |
| SHORT - CIRCUIT FAULT PROTECTION | ||||||
| Time for Validating Short - Circuit Fault Condition | 2 | t protect | - | 130 | - | ms |
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions.
-
Please refer to Figure 39 for detailed description.
-
Guaranteed by design.
ELECTRICAL CHARACTERISTICS (continued) (For typical values T J = 25 C, for min/max values, T J = -40 C to +125 C, VCC = 14 V, HV = open, skip = open, FB = 2 V, CS = Ground, DRV = 1 nF, unless otherwise noted.)
| Characteristic | Pin | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| STARTUP CURRENT SOURCE | ||||||
| High - Voltage Current Source Inhibit Voltage (I = 200 m A, HV = 50 V) | 6 | V inhibit I inhibit | 190 80 | 600 | 800 | mV |
| CC Inhibit Current (V CC = 0 V, HV = 50 V) | 6 | 200 | 350 | m A | ||
| Startup (V CC = V CC(on) - 0.2 V, HV = 50 V) | 6 | I HV | 3.0 | 4.1 | 6.0 | mA |
| Leakage (V CC = 14 V, HV = 500 V) | 8 | I HV - leak | 10 | 25 | 50 | m A |
| Minimum Startup Voltage (V CC = V CC(on) - 0.2 V, I CC = 0.5 mA) | 8 | V HV(min) | - | 20 | 28 | V |
| SUPPLY SECTION | ||||||
| V CC Regulation | 6 | |||||
| Startup Threshold, V CC Increasing | V CC(on) | 11.2 | 12.6 | 13.8 | V | |
| Minimum Operating Voltage After Turn - On | V CC(off) | 8.2 | 9.1 | 10 | V | |
| V CC Operating Hysteresis | V CC(on) - V CC(off) | 3.0 | 3.6 | 4.2 | V | |
| Undervoltage Lockout Threshold Voltage, V CC Decreasing | V CC(latch) | 5.0 | 5.8 | 6.5 | V | |
| Logic Reset Level (V CC(latch) -V CC(reset) > 1.0 V) (Note 7) | V CC(reset) | - | 4.0 | - | V | |
| V CC Supply Current | 6 | |||||
| Operating (V CC = 14 V, 1.0 nF Load, V FB = 2.0 V, 65 kHz Version) | I CC1 | - | 2.3 | 3.0 | mA | |
| Operating (V CC = 14 V, 1.0 nF Load, V FB = 2.0 V, 100 kHz Version) | I CC1 | - | 3.1 | 3.5 | mA | |
| Output Stays Low (V CC = 14 V, V FB = 0 V) | I CC2 | - | 1.3 | 2.0 | mA | |
| Latchoff Phase (V CC = 7.0 V, V FB = 2.0 V) | I CC3 | - | 500 | 720 | m A |
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions.
- Guaranteed by design.
Figure 3. Oscillation Frequency vs. Temperature
Figure 4. Maximum Duty Cycle vs. Temperature
Figure 5. Output Gate Drive Resistance vs. Temperature
Figure 7. Soft -Start Duration vs. Temperature
Figure 9. Default Skip Level vs. Temperature
Figure 6. Current Limit vs. Temperature
Figure 8. Leading Edge Blanking Time vs. Temperature
Figure 10. Skip Pin Current vs. Temperature
Figure 11. Skip Level Reset Threshold vs. Temperature
Figure 12. Transient Load Detection Level vs. Temperature
Figure 13. Latch Protection Level vs. Temperature
Figure 15. Startup Inhibit Voltage vs. Temperature
Figure 14. Fault Validation Time vs. Temperature
Figure 16. Startup Inhibit Current vs. Temperature
Figure 17. High Voltage Startup Current vs. Temperature
Figure 19. Startup Leakage Current vs. Temperature
Figure 18. Startup Current vs. V CC Voltage
Figure 20. Minimum Startup Voltage vs. Temperature
Figure 21. Supply Voltage Thresholds vs. Temperature
Figure 22. Supply Currents vs. Temperature
NCP1271 Absolute Maximum Ratings
| Rating | Symbol | Value | Unit |
|---|---|---|---|
| V CC Pin (Pin 6) | |||
| Maximum Voltage Range Maximum Current | V max I max | - 0.3 to +20 100 | V mA |
| Skip/Latch, FB, CS Pin (Pins 1 - 3) Maximum Voltage Range Maximum Current | V max I max | - 0.3 to +10 100 | V mA |
| Drv Pin (Pin 5) | |||
| Maximum Voltage Range | V max I | - 0.3 to +20 | V |
| HV Pin (Pin 8) Maximum Voltage | max | ||
| Maximum Current | max V | - 0.3 to +500 | V |
| Maximum Current Power Dissipation and Thermal Characteristics Thermal Resistance, Junction - to - Air, PDIP - 7, Low Conductivity Thermal Resistance, Junction - to - Lead, PDIP - 7, Low | - 800 to +500 | mA | |
| Range | R q JA R q JL | 142 57 | C/W C/W |
| PCB (Note 3) Conductivity PCB | I max | 100 | mA |
| Thermal Resistance, Junction - to - Air, PDIP - 7, High Conductivity PCB (Note 4) Thermal Resistance, Junction - to - Lead, PDIP - 7, High Conductivity PCB | R q JA | C/W | |
| q | 120 | C/W | |
| 3) | 56 | ||
| R JL | 177 | ||
| Thermal Resistance, Junction - to - Air, SO - 7, Low Conductivity PCB (Note Thermal Resistance, Junction - to - Lead, SO - 7, Low Conductivity PCB | R q JA | C/W C/W | |
| R q JL | 75 | ||
| Thermal Resistance, Junction - to - Air, SO - 7, High Conductivity PCB (Note 4) | R q JA | 136 | C/W |
| Thermal Resistance, Junction - to - Lead, SO - 7, High Conductivity PCB | R q JL | 69 | C/W |
| Operating Junction Temperature Range | T J | - 40 to +150 | C |
| Maximum Storage Temperature Range | T | - 60 to +150 | C |
| ESD Protection 6 | stg HBM HBM | 2000 700 150 | V V |
| Human Body Model ESD Pins 1 - Human Body Model ESD Pin 8 Machine Model ESD Pins 1 - 4, 8 | MM | 200 | V V |
| Machine Model ESD Pins 5, 6 | MM | ||
| Charged Device Model ESD | |||
| CDM | 1000 | V |
NCP1271 Typical Application
- AC -DC Adapters for Notebooks, LCD Monitors
- Offline Battery Chargers
- Consumer Electronic Appliances STB, DVD, DVDR
1
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