## Overview of the ACT413 Electronic Component The **ACT413** is a high-performance, low-power **PWM (Pulse Width Modulation) Controller** specifically designed for offline AC/DC flyback converters. It is part of the Active-Semi (now Qorvo) family of primary-side regulators. Its primary application is in power adapters for mobile devices, set-top boxes, and network equipment where energy efficiency and low component count are critical. --- ### Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Topology** | Primary-Side Regulation (PSR) Flyback | | **Operating Frequency** | Up to 75kHz | | **Standby Power** | < 30mW (Ultra-low) | | **Control Method** | CV/CC (Constant Voltage / Constant Current) | | **Package Type** | SOT23-6 | | **Efficiency Standard** | Meets DoE Level VI and CoC Tier 2 | --- ### Internal Electronic Functions The ACT413 integrates several complex circuits into a single 6-pin package to manage power conversion without needing an optocoupler: 1. **Primary-Side Regulation (PSR):** It senses the output voltage via the auxiliary winding of the transformer. This eliminates the need for an optocoupler and TL431 shunt regulator, reducing cost and footprint. 2. **Frequency Shaking:** The IC incorporates an internal frequency shuffling technique to reduce EMI (Electromagnetic Interference) emissions, allowing for smaller, cheaper EMI filters. 3. **Advanced Protection Circuitry:** * **OTP:** Over Temperature Protection. * **OVP:** Over Voltage Protection. * **SCP:** Short Circuit Protection. * **UVLO:** Under-Voltage Lockout to ensure stable startup. 4. **Adaptive Driving:** It adjusts the gate drive current based on the load to optimize switching losses and efficiency across the entire load range. --- ### Typical Pin Configuration (SOT23-6) | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **VDD** | Power supply input for the IC. | | 2 | **GATE** | Gate driver output for the external MOSFET. | | 3 | **CS** | Current sense input to monitor primary peak current. | | 4 | **FB** | Feedback input from the auxiliary winding. | | 5 | **COMP** | Compensation pin for loop stability. | | 6 | **GND** | Ground reference. | --- ### Application Circuit Diagram Concept ```mermaid graph LR AC_Input --> Rectifier Rectifier --> Transformer_Primary Transformer_Primary --> MOSFET MOSFET --> CS_Resistor ACT413 -- Gate_Drive --> MOSFET Aux_Winding -- Feedback --> ACT413 Transformer_Secondary --> Output_DC ``` ---