Overview
The NCP1203P100, produced by onsemi, is a PWM Current-Mode Controller designed for universal off-line power supplies. It is housed in either an SOIC-8 or PDIP-8 package and represents a significant advancement in ultra-compact switchmode power supplies. This controller is an excellent candidate to replace UC384X devices due to its proprietary SMARTMOS™ Very High Voltage Technology. The NCP1203P100 operates at a fixed switching frequency of 100 kHz and features a high-voltage startup FET, ensuring a clean and lossless startup sequence. It is particularly suited for applications requiring low part-count, such as low-cost AC-DC adapters and auxiliary power supplies.
Key Specifications
| Characteristic | Symbol | Pin | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| Turn-on Threshold Level, VCC Going Up | VCC(on) | 6 | 12.2 | 12.8 | 14 | V |
| Minimum Operating Voltage after Turn-on | VCC(min) | 6 | 7.2 | 7.8 | 8.4 | V |
| Internal IC Consumption, No Output Load on Pin 5 | ICC1 | 6 | - | 750 | 880 | μA |
| Internal IC Consumption, 1.0 nF Output Load on Pin 5, FSW = 100 kHz | ICC2 | 6 | - | 1.2 | 1.4 | mA |
| Peak Current Capability | - | - | - | - | 250 mA | - |
| Switching Frequency | - | - | - | - | 100 kHz | - |
Key Features
- High-Voltage Startup Current Source
- Auto-Recovery Internal Output Short-Circuit Protection
- Extremely Low No-Load Standby Power
- Current-Mode with Adjustable Skip-Cycle Capability
- Internal Leading Edge Blanking
- 250 mA Peak Current Capability
- Internally Fixed Frequency at 100 kHz
- Direct Optocoupler Connection
- Undervoltage Lockout at 7.8 V Typical
- SPICE Models Available for Transient and AC Analysis
- Pin to Pin Compatible with NCP1200
- Pb-Free, Halogen Free/BFR Free and RoHS Compliant
Applications
- AC-DC Adapters for Notebooks, etc.
- Offline Battery Chargers
- Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
Q & A
- What is the primary function of the NCP1203P100?
The NCP1203P100 is a PWM Current-Mode Controller designed for universal off-line power supplies, particularly suited for applications like AC-DC adapters and auxiliary power supplies.
- What are the available switching frequencies for the NCP1203 series?
The NCP1203 series operates at fixed switching frequencies of 40 kHz, 60 kHz, or 100 kHz.
- How does the NCP1203P100 handle low-load conditions?
The NCP1203P100 automatically enters a skip cycle mode at low-load conditions, improving efficiency and reducing standby power consumption.
- What kind of protection does the NCP1203P100 offer?
The NCP1203P100 includes auto-recovery internal output short-circuit protection, temperature shutdown with hysteresis, and overcurrent protection.
- Is the NCP1203P100 environmentally friendly?
Yes, the NCP1203P100 is Pb-Free, Halogen Free/BFR Free, and RoHS Compliant.
- How does the high-voltage startup FET contribute to the operation of the NCP1203P100?
The high-voltage startup FET ensures a clean and lossless startup sequence by injecting a constant current into the VCC capacitor during startup.
- What is the purpose of the Adj pin on the NCP1203P100?
The Adj pin allows the adjustment of the skipping peak current level, enabling the designer to set the point at which the skip cycle occurs.
- Can the NCP1203P100 be used in place of UC384X devices?
Yes, the NCP1203P100 is designed to be pin-to-pin compatible with NCP1200 and can replace UC384X devices in many applications.
- What is the significance of the internal leading edge blanking feature?
The internal leading edge blanking feature helps in reducing noise and improving the accuracy of current sensing.
- How does the NCP1203P100 manage overcurrent conditions?
In the presence of an output overload condition, the NCP1203P100 disables the output pulses and enters a safe burst mode, attempting to restart once the fault is cleared.
