Overview
The NCP1207BDR2G, produced by onsemi, is a PWM current-mode controller designed for free-running quasi-resonant operation. This IC combines a true current mode modulator and a demagnetization detector, ensuring full borderline/critical conduction mode in various load and line conditions. It features high-voltage technology, allowing direct connection to the high-voltage DC rail, and includes several protection mechanisms such as overvoltage protection (OVP) and overcurrent protection (OCP). The NCP1207BDR2G is particularly useful in applications where low part count and high reliability are crucial.
Key Specifications
| Parameter | NCP1207B |
|---|---|
| Package Type | SOIC-8 (Pb-Free) |
| Operating Frequency | Up to 200 kHz |
| Minimum TOFF (Internal Blanking Delay) | 4.5 μs |
| Peak Current Source/Sink Capability | 500 mA |
| Undervoltage Lockout (VCC) | Below 10 V |
| Internal Soft-Start Time | 1.0 ms |
| Overvoltage Protection (OVP) Reference Level | 5.0 V (adjustable) |
| Internal Temperature Shutdown | Yes |
| Dynamic Self-Supply (DSS) | Yes |
Key Features
- Free-running borderline/critical conduction mode quasi-resonant operation
- Current-mode with adjustable skip-cycle capability
- No auxiliary winding VCC operation due to Dynamic Self-Supply (DSS)
- Auto-recovery overcurrent protection and latching overvoltage protection
- External latch triggering via overtemperature signal
- Internal 1.0 ms soft-start and internal temperature shutdown
- Direct optocoupler connection and SPICE models available for transient analysis
- Pb-Free and Halide-Free device
Applications
The NCP1207BDR2G is ideal for applications where low part count and high reliability are essential, such as:
- Low-cost AC/DC adapters
- Consumer electronics
- Auxiliary power supplies
- Battery chargers with variable output voltage
Q & A
- What is the primary function of the NCP1207BDR2G?
The NCP1207BDR2G is a PWM current-mode controller designed for free-running quasi-resonant operation in switch-mode power supplies.
- What is the maximum operating frequency of the NCP1207BDR2G?
The NCP1207BDR2G can operate up to 200 kHz.
- What is the purpose of the Dynamic Self-Supply (DSS) feature?
The DSS feature allows the IC to operate without an auxiliary winding, simplifying transformer design and ensuring a fully independent VCC level.
- How does the overvoltage protection (OVP) work in the NCP1207BDR2G?
The OVP works by sampling the plateau voltage on the demagnetization winding and entering a latched fault condition if an overvoltage is detected.
- What is the significance of the internal soft-start feature?
The internal 1.0 ms soft-start feature helps in gradually increasing the output voltage during startup, preventing high inrush currents.
- Can the NCP1207BDR2G be used in battery charger applications?
Yes, the NCP1207BDR2G is suitable for battery charger applications, especially those with variable output voltage, due to its DSS and OVP features.
- How does the skip cycle capability work in the NCP1207BDR2G?
The skip cycle capability allows the controller to enter burst mode when power demand falls below a predetermined level, reducing audible noise and power consumption.
- What is the purpose of the internal temperature shutdown feature?
The internal temperature shutdown feature protects the IC from overheating by shutting down the device when the temperature exceeds a certain threshold.
- Is the NCP1207BDR2G Pb-Free and Halide-Free?
Yes, the NCP1207BDR2G is both Pb-Free and Halide-Free, making it environmentally friendly.
- How does the demagnetization detection work in the NCP1207BDR2G?
The demagnetization detection is done through an auxiliary winding, which triggers the turn-on event and ensures quasi-resonant operation.
