The **TOP250F** is a member of the **TOPSwitch-GX** family produced by Power Integrations. It is an integrated switched-mode power supply (SMPS) controller that combines a high-voltage power MOSFET and control circuitry onto a single CMOS chip. --- ### 1. Key Internal Components The TOP250F integrates several discrete functions into one package to simplify power supply design: | Component | Function | | :--- | :--- | | **High-Voltage MOSFET** | A 700V power MOSFET that handles the high-frequency switching. | | **PWM Controller** | Regulates the output voltage by adjusting the pulse width. | | **Error Amplifier** | Compares feedback to an internal reference to maintain stability. | | **Soft-Start Circuit** | Reduces thermal and electrical stress during initial power-up. | | **Protection Logic** | Includes thermal shutdown and over-current protection. | --- ### 2. Technical Specifications The "F" suffix in TOP250F specifically refers to the **TO-220-7B** plastic package (also known as Y-package or TO-220). | Parameter | Value | | :--- | :--- | | **Drain Voltage (Max)** | 700 V | | **Output Power (Adapter)** | Up to 125 W (at 230 VAC) | | **Output Power (Open Frame)** | Up to 210 W (at 230 VAC) | | **Switching Frequency** | 132 kHz (standard) or 66 kHz (jitter mode) | | **Operating Temperature** | -40°C to 150°C | --- ### 3. Pin Configuration (TO-220-7B) The TOP250F typically uses a multi-pin configuration to allow for advanced features like remote sensing and frequency synchronization. 1. **DRAIN (D):** High-voltage MOSFET drain output; provides internal operating current during start-up. 2. **CONTROL (C):** Error amplifier and feedback current input pin for duty cycle control. 3. **EXTERNAL SET CURRENT (X):** Used for remote ON/OFF and setting the external current limit. 4. **LINE-SENSE (L):** Provides input under-voltage (UV) and over-voltage (OV) protection. 5. **FREQUENCY (F):** Input pin for selecting the switching frequency (132 kHz or 66 kHz). 6. **SOURCE (S):** Output MOSFET source connection; ground reference for control circuitry. --- ### 4. Advanced Features * **Frequency Jittering:** Spreads the energy of the switching harmonics over a wider frequency range, significantly reducing Electro-Magnetic Interference (EMI). * **Line Feed-Forward:** Adjusts the duty cycle based on line voltage to reject ripple. * **Hysteretic Thermal Shutdown:** Automatically shuts the device down if it overheats and restarts once it cools. * **EcoSmart Technology:** Highly efficient under light load or no-load conditions, meeting global energy savings standards. --- ### 5. Application Example ```c // Typical Power Supply Topology: Flyback Converter [AC Input] -> [Bridge Rectifier] -> [Bulk Capacitor] -> [Transformer Primary] | [TOP250F Drain] | [Feedback Optocoupler] -> [TOP250F Control Pin] <------------+ ```