LNK6404D

The LNK6404D is an offline switching controller from Power Integrations, which serves as an incredibly capable power management component for multiple electronic products. It is an ideal solution for products that require extremely efficient, low cost, and high reliability. This is because the integrated technologies of the controller allow it to provide optimal power regulation and protection from under-voltage, over-voltage, short-circuiting and power overloading scenarios.

The controller is specifically designed for high voltage flyback switching converters, driving an isolated transformer, for both single and dual-ended secondary configurations. It combines many features such as maximum peak and line voltage sensing, over-temperature protection, a Low Standby-Power Loss Burst ModeTM architecture, and a Self-Supply ModeTM. It also features a small, thermally efficient 8-pin wafer-level package that enables it to operate over a wide temperature range.

The controller’s primary application field is the power supply of AC output home appliances. It works to switch an output voltage, endures energy efficiency regulations, has constant current/voltage regulation performances, and withstands long-term reliability tests. The LNK6404D power conversion solution provides a high performance, low component count, integrated control solution for universal input, high-efficiency offline flyback ac/dc power supplies that require minimal external components.

The working principle of the controller is somewhat similar to that of a classic switching power supply. The converter includes a main switch for connecting the secondary side of the transformer to the AC line, removing the same amount of energy from the line as is delivered to the plug-in device. To control this quantity of energy, the LNK6404D is loaded with a set of built-in protection and conditioning circuits, which are used to monitor and manage the energy exchange process and to ensure the correct operating conditions at the output stage.

The LNK6404D is composed of three main functional stages that allow it to measure, regulate, and protect the output voltage. To begin, it acts as a Flyback Controller, by activating and deactivating the main switch, in order to provide a regulation loop using peak current sensing and hysteresis feedback. Secondly, a protection and voltage regulation module containing a current-mode PWM, OVP, and OTP circuitry, is employed for the line disconnection during the fault conditions. Lastly, in order to suppress EMI, and reduce component count, the controller contains a 5th order EMI filter, allowing a 25-dB reduction of EMI at low cost and minimal component count.

In conclusion, the LNK6404D from Power Integrations, is an offline switching controller, tailored for AC output home appliance, that integrates multiple protection and buffer circuits for efficiency, reliability, and cost effectiveness. It operates through a highly efficient Flyback Controller and current-mode protection scheme, managing the EMI filter, peak current sensing and hysteresis, in order to ensure a safe, high performance and low component count.