Overview
The NCP1377BDR2, produced by onsemi, is a PWM Current-Mode Controller designed for free-running quasi-resonant operation. This controller combines a true current mode modulator and a demagnetization detector, ensuring full borderline/critical Conduction Mode in any load/line conditions. It features minimum drain voltage switching (Quasi-Resonant operation) and inherent skip cycle capability, which allows the controller to enter burst mode when power demand falls below a predetermined level, eliminating audible noise. The NCP1377BDR2 is particularly suited for applications requiring low part-count and high-performance high-voltage technology, such as AC-DC adapters, consumer electronics, and auxiliary supplies.
Key Specifications
| Characteristic | Pin Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| VCC Increasing Level at which the Current Source Turns-Off | VCCON | 11.6 | 12.5 | 13.7 | V |
| Minimum Operating Voltage after Turn-On | VCCOFF | 7.0 | 7.5 | 8.2 | V |
| VCC Decreasing Level at which the Latchoff Phase Ends | VCClatch | - | 5.6 | - | V |
| Internal IC Consumption, No Output Load on Pin 5, FSW = 60 kHz | ICC1 | 1.0 | 1.3 | - | mA |
| Maximum Internal Current Setpoint | ILimit | 0.9 | 1.0 | 1.1 | V |
| Propagation Delay from Current Detection to Gate OFF State | TDEL | 100 | 160 | - | ns |
| Leading Edge Blanking Duration | TLEB | - | 380 | - | ns |
| Sampling Delay After ON Time (NCP1377B) | Tsample | - | 1.5 | - | μs |
| Internal Soft-Start | Tss | - | 1.0 | - | ms |
| Maximum Junction Temperature | TJMAX | - | - | 150 | °C |
Key Features
- Free-Running Borderline/Critical Mode Quasi-Resonant Operation
- Latched Overvoltage Protection (OVP)
- 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 Voltage Lockout Level of 12.5 V (On) and 7.5 V (Min)
- Direct Optocoupler Connection
- SPICE Models Available for Transient Analysis
Applications
- AC-DC Adapters for Notebooks, etc.
- Offline Battery Chargers
- Consumer Electronics
- Auxiliary Supplies
Q & A
- What is the primary function of the NCP1377BDR2?
The NCP1377BDR2 is a PWM Current-Mode Controller designed for free-running quasi-resonant operation, ensuring full borderline/critical Conduction Mode in any load/line conditions.
- What is the significance of the skip cycle capability in the NCP1377BDR2?
The skip cycle capability allows the controller to enter burst mode when power demand falls below a predetermined level, eliminating audible noise and reducing power consumption.
- How does the NCP1377BDR2 protect against overvoltage conditions?
The NCP1377BDR2 features latched overvoltage protection (OVP) that permanently latches off the IC when an overvoltage condition is detected, requiring a power cycle to reset.
- What is the purpose of the internal soft-start feature in the NCP1377BDR2?
The internal 1.0 ms soft-start feature eliminates traditional startup stress by gradually increasing the output voltage during startup.
- What are the typical applications of the NCP1377BDR2?
The NCP1377BDR2 is typically used in AC-DC adapters, offline battery chargers, consumer electronics, and auxiliary supplies.
- How does the NCP1377BDR2 handle short-circuit conditions?
The NCP1377BDR2 features auto-recovery short-circuit protection via UVLO crossover, which disables output pulses and enters a safe burst mode to restart once the fault is cleared.
- What is the maximum junction temperature for the NCP1377BDR2?
The maximum junction temperature for the NCP1377BDR2 is 150°C.
- Does the NCP1377BDR2 support external latch triggering?
Yes, the NCP1377BDR2 supports external latch triggering, for example, via an overtemperature signal.
- What is the peak current source/sink capability of the NCP1377BDR2?
The NCP1377BDR2 has a 500 mA peak current source/sink capability.
- Are SPICE models available for the NCP1377BDR2?
Yes, SPICE models are available for transient analysis of the NCP1377BDR2.
