Overview
The NCP1203P40G, 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, such as AC-DC adapters, offline battery chargers, and auxiliary power supplies. The NCP1203P40G operates at a fixed switching frequency of 40 kHz and includes a high-voltage startup FET for a clean and lossless startup sequence. It also offers current-mode control with inherent pulse-by-pulse control and good audio-susceptibility.
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 = 40 kHz | ICC2 | 6 | - | 1.2 | 1.4 | mA |
| Oscillation Frequency, 40 kHz Version | fOSC | - | 37 | 42 | 47 | kHz |
| Maximum Duty-Cycle | Dmax | - | 74 | 80 | 87 | % |
| Peak Current Capability | - | - | - | 250 | - | mA |
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 40 kHz, 60 kHz, and 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 NCP1203P40G?
The NCP1203P40G 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 NCP1203P40G?
The NCP1203P40G operates at fixed switching frequencies of 40 kHz, 60 kHz, and 100 kHz.
- How does the NCP1203P40G handle overcurrent protection?
The NCP1203P40G includes an efficient protective circuitry that disables output pulses and enters a safe burst mode in the presence of an output overload condition. It auto-recovers once the fault condition disappears.
- What is the purpose of the skip cycle mode in the NCP1203P40G?
The skip cycle mode allows the controller to skip switching cycles when the output power demand drops below a given level, reducing standby power and ensuring noise-free operation.
- How does the NCP1203P40G ensure a clean startup sequence?
The NCP1203P40G features a high-voltage startup FET that injects a constant current into the VCC capacitor during the startup sequence, ensuring a clean and lossless startup.
- What is the maximum duty cycle of the NCP1203P40G?
The maximum duty cycle of the NCP1203P40G is 80%.
- Is the NCP1203P40G compatible with other devices?
Yes, the NCP1203P40G is pin-to-pin compatible with the NCP1200.
- What are the environmental compliance standards for the NCP1203P40G?
The NCP1203P40G is Pb-Free, Halogen Free/BFR Free, and RoHS Compliant.
- How does the NCP1203P40G handle short circuit protection?
The NCP1203P40G features an auto-recovery output short-circuit protection that stops switching pulses and reduces consumption when a short circuit is detected, and auto-recovers once the fault condition disappears.
- What is the typical undervoltage lockout level for the NCP1203P40G?
The typical undervoltage lockout level for the NCP1203P40G is 7.8 V.
