Overview
The NCP1200P40G, produced by onsemi, is a PWM current-mode controller designed for low-power universal offline power supplies. It is housed in a PDIP-8 package and represents a significant advancement in ultra-compact switch-mode power supplies. This controller allows for the implementation of complete offline battery chargers or standby SMPS with minimal external components. It features an integrated output short-circuit protection, enabling the design of extremely low-cost AC/DC wall adapters with simplified feedback schemes. The NCP1200 operates at a fixed frequency of 40 kHz and drives low gate-charge switching devices like IGBTs or MOSFETs, requiring very small operating power. It also includes current-mode control with skip-cycle capability, ensuring excellent efficiency at light loads and minimizing acoustic noise.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Package Type | PDIP-8 | |
| Switching Frequency | 40 kHz | kHz |
| Control Mode | Current Mode | |
| Peak Current Source/Sink Capability | 250 mA | mA |
| Internal Temperature Shutdown | Yes | |
| Internal Output Short-Circuit Protection | Yes | |
| No Auxiliary Winding Operation | Yes | |
| Maximum Duty Cycle | 74-87% | % |
| VCC Decreasing Level at Which the Current Source Turns-on | 8.8-11 V | V |
| Internal IC Consumption (No Output Load) | 710-880 μA | μA |
Key Features
- No Auxiliary Winding Operation: The NCP1200 is self-supplied from the DC rail, eliminating the need for an auxiliary winding.
- Internal Output Short-Circuit Protection: Protects against output short circuits, enabling the design of low-cost AC/DC adapters.
- Extremely Low No-Load Standby Power: Ensures high efficiency at light loads.
- Current-Mode with Skip-Cycle Capability: Automatically enters skip cycle mode when the current setpoint falls below a given value, reducing acoustic noise and improving efficiency.
- Internal Leading Edge Blanking: Reduces noise and improves reliability.
- 250 mA Peak Current Source/Sink Capability: Supports driving low gate-charge switching devices.
- Internally Fixed Frequency at 40 kHz, 60 kHz, and 100 kHz: Provides flexibility in design.
- Direct Optocoupler Connection: Simplifies feedback schemes.
- Built-in Frequency Jittering for Lower EMI: Reduces electromagnetic interference.
- SPICE Models Available for Transient and AC Analysis: Facilitates detailed design and simulation.
- Internal Temperature Shutdown: Ensures safe operation by shutting down at high temperatures.
Applications
- AC/DC Adapters: Ideal for designing compact and efficient power adapters.
- Offline Battery Chargers: Suitable for battery charging applications with minimal external components.
- Auxiliary/Ancillary Power Supplies: Used in USB, appliances, TVs, and other auxiliary power supply applications.
Q & A
- What is the primary function of the NCP1200P40G?
The NCP1200P40G is a PWM current-mode controller designed for low-power universal offline power supplies.
- What package types are available for the NCP1200?
The NCP1200 is available in SOIC-8 and PDIP-8 packages.
- What are the switching frequencies available for the NCP1200?
The NCP1200 operates at fixed frequencies of 40 kHz, 60 kHz, and 100 kHz.
- Does the NCP1200 require an auxiliary winding?
No, the NCP1200 is self-supplied from the DC rail, eliminating the need for an auxiliary winding.
- What is the peak current source/sink capability of the NCP1200?
The NCP1200 has a peak current source/sink capability of 250 mA.
- How does the NCP1200 handle low load conditions?
The NCP1200 automatically enters skip cycle mode when the current setpoint falls below a given value, ensuring excellent efficiency at light loads and minimizing acoustic noise.
- What is the maximum duty cycle of the NCP1200?
The maximum duty cycle of the NCP1200 is between 74% and 87%.
- Does the NCP1200 have built-in temperature shutdown?
Yes, the NCP1200 has internal temperature shutdown to ensure safe operation.
- What are some typical applications of the NCP1200?
Typical applications include AC/DC adapters, offline battery chargers, and auxiliary/ancillary power supplies.
- Is the NCP1200 RoHS compliant?
Yes, the NCP1200 is Pb-free, halogen-free/BFR-free, and RoHS compliant.
