In modern electronic devices, the Switching Mode Power Supply (SMPS) is an essential energy conversion system. One of its most critical components is the switching power controller IC . Among various options, the TOPSwitch series by Power Integrations stands out for its high integration and efficiency. Specifically, the TOP248YN is a widely adopted model for medium- and small-sized power supplies.     This post will explore the internal structure and operation of the TOP248YN and explain how it is applied in real-world circuit designs. 1. Introduction to TOP248YN TOP248YN is a highly integrated switching power solution that combines a PWM controller and high-voltage MOSFET into a single chip. It accepts an AC input of 85–265V and outputs various DC voltages, supporting up to 65W under preheat conditions. Manufacturer: Power Integrations Package: TO-220-7C Built-in functions: high-voltage MOSFET, current limit, oscillator, feedback contro...

Among the essential components in electronic circuits, capacitors always take a prominent place. In particular, electrolytic capacitors are indispensable for power supply and filter circuits. While they don’t appear to directly control current, their role in stabilizing the circuit is critical and often determines the reliability of the entire device.     In this article, we will dive into the structure and characteristics of electrolytic capacitors, and see how they work as the unsung heroes of smoothing circuits. 1. What Is an Electrolytic Capacitor? An electrolytic capacitor is a polarized capacitor that uses an electrolyte, typically consisting of an aluminum anode, an oxide layer, and an electrolyte . This structure allows it to achieve much larger capacitance compared to other types of capacitors, all within a relatively small package. On the downside, it has polarity , meaning it must be connected correctly, or it risks failure or even explos...

When you open up an electronic device, you might come across a small cylindrical or rectangular component labeled “F1.” That tiny part is a fuse . Although it may look insignificant, a fuse plays a vital role—it acts as the first line of defense to protect your device when excessive current flows through the circuit.     In this post, we'll explore why fuses are essential, how they work, and how they fit into the overall overcurrent protection structure in electronic devices. 1. What Is a Fuse? A fuse is a protective device that interrupts the electrical circuit when the current exceeds a certain limit. It contains a metal wire or strip that melts when too much current flows through it, breaking the circuit and preventing further damage. The operation is simple: when overcurrent occurs, the metal heats up, melts, and disconnects the power flow. This quick response prevents components from overheating or catching fire. 2. Why Is a Fuse Absolutely Neces...

In a typical power supply circuit, the bridge rectifier plays a central role. It converts alternating current (AC) into direct current (DC), allowing stable and consistent power delivery to electronic components. In particular, the integrated bridge rectifier module simplifies circuit design by consolidating four diodes into a single package.     1. What Is an Integrated Bridge Rectifier? An integrated bridge rectifier module is a component that combines four diodes into one compact package. It features four terminals: two for AC input and two for DC output. The main advantage is its ease of use and reduced soldering points on the PCB. 2. Advantages of Using a Bridge Rectifier Module Compact Design: Reduces the area needed on the circuit board. Simplified Assembly: Easier soldering with fewer connections. Enhanced Reliability: Pre-tested components minimize errors.     3. Pinout and Structure Bridge rectifier modules usua...

Thermistors may be small, but their role in electronic circuits, especially power supply boards, is massive. Among them, NTC (Negative Temperature Coefficient) thermistors are frequently used as inrush current limiters. This post walks you through how NTC thermistors work, why they’re wired in series with hotlines, and how to test or diagnose them.     What Is an NTC Thermistor? An NTC thermistor is a temperature-sensitive resistor that decreases its resistance as temperature increases. When cold, it provides high resistance; as it heats up (due to current flow), its resistance drops, allowing higher current to flow safely into the circuit. This makes it perfect for power-up scenarios where large capacitors or switching components could otherwise cause a surge. Why Is It Wired in Series on the Hot Line? The primary role of an NTC thermistor in a power circuit is inrush current suppression. It is always installed in series with the AC input "hotline." On s...

An NTC (Negative Temperature Coefficient) thermistor is an essential component used in the power supply section of electronic devices. It is commonly connected in series with the AC input line and is responsible for suppressing inrush current at the moment of power-up.     Structure and Principle of NTC Thermistor An NTC thermistor consists of a semiconductor ceramic element whose resistance decreases as the temperature rises. At room temperature, it maintains high resistance, limiting the inrush current when power is first applied. As the device warms up, the resistance rapidly drops, allowing stable current flow with minimal power loss. Main Functions of NTC Thermistor Suppressing inrush current: protects bridge diodes and capacitors from surge damage Gradual startup of power supply: ensures smooth charging of electrolytic capacitors Thermal protection: can act as a safety element if placed near heating elements     ...

Interest in digital currencies is rapidly growing worldwide. Among them, Central Bank Digital Currencies (CBDCs) are attracting the most attention from governments and financial institutions. In this post, we’ll explain what a CBDC is and how it differs fundamentally from cryptocurrencies like Bitcoin.     What Is CBDC? CBDC stands for Central Bank Digital Currency. It is a digital version of legal tender issued by a country's central bank. Like physical cash (banknotes and coins), CBDC is backed by the government, but it exists in digital form, often operating on blockchain or centralized databases. For instance, a CBDC issued by the Bank of Korea would carry the same legal value as Korean won and can be used for sending, receiving, and making payments via digital wallets. CBDC vs. Cryptocurrency: What's the Difference? Many people confuse CBDCs with cryptocurrencies. However, they are completely different in philosophy, structure, and function. ...