Overview
The NCP1203P60G, produced by onsemi, is a PWM Current-Mode Controller designed for universal off-line power supplies. It features onsemi's proprietary SMARTMOS™ Very High Voltage Technology, making it an excellent candidate for replacing UC384X devices. This controller is housed in either an SOIC-8 or PDIP-8 package and is ideal for applications requiring low part-count and high performance, such as AC-DC adapters, offline battery chargers, and auxiliary power supplies.
The NCP1203P60G operates at a fixed switching frequency of 60 kHz and includes a high-voltage startup FET for a clean and loss-less startup sequence. It also offers current-mode control with adjustable skip-cycle capability, ensuring good audio-susceptibility and inherent pulse-by-pulse control.
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 = 60 kHz | ICC2 | 6 | - | 1.2 | 1.4 | mA |
| Oscillation Frequency, 60 kHz Version | fOSC | - | 57 | 65 | 73 | kHz |
| Maximum Duty-Cycle | Dmax | - | 74 | 80 | 87 | % |
| Maximum Current into all pins except Pin 6 (VCC) and Pin 8 (HV) | - | - | -0.3 to 10 | V |
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 60 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 NCP1203P60G?
The NCP1203P60G is a PWM Current-Mode Controller designed for universal off-line power supplies, featuring high-voltage startup and current-mode control.
- What are the available switching frequencies for the NCP1203?
The NCP1203 is available in three switching frequency options: 40 kHz, 60 kHz, and 100 kHz.
- How does the skip cycle mode work in the NCP1203P60G?
The skip cycle mode is activated when the output power demand drops below a given level, monitored by the FB pin. This mode skips switching cycles to improve efficiency at light loads and reduce standby power.
- What is the purpose of the high-voltage startup FET in the NCP1203P60G?
The high-voltage startup FET ensures a clean and loss-less startup sequence by injecting a constant current into the VCC capacitor during startup.
- How does the NCP1203P60G protect against overcurrent conditions?
The NCP1203P60G includes an efficient protective circuitry that disables output pulses and enters a safe burst mode in the presence of an output overload condition. It also features auto-recovery once the fault condition disappears.
- What is the significance of the undervoltage lockout (UVLO) in the NCP1203P60G?
The UVLO at 7.8 V typical ensures that the controller stops switching and reduces consumption when the auxiliary voltage falls below this level, preventing thermal runaway in overload conditions.
- Can the NCP1203P60G be used in applications requiring low no-load standby power?
Yes, the NCP1203P60G is designed to provide extremely low no-load standby power, making it suitable for applications such as AC-DC adapters and VCRs.
- Is the NCP1203P60G compatible with other devices?
The NCP1203P60G is pin-to-pin compatible with the NCP1200, making it a suitable replacement in existing designs.
- What are the environmental compliance features of the NCP1203P60G?
The NCP1203P60G is Pb-Free, Halogen Free/BFR Free, and RoHS Compliant.
- How does the temperature shutdown feature work in the NCP1203P60G?
The NCP1203P60G includes a temperature shutdown with hysteresis to ensure safe and robust power supply operation by shutting down the device if it exceeds the maximum temperature limit.
