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Field Effect Transistor (FET / MOSFET) – Detailed Introduction
What is a FET A Field Effect Transistor (FET) is a voltage-controlled semiconductor device. Unlike bipolar transistors (BJT) which rely on input current to turn on, FET works by applying a voltage to the gate terminal. The electric field generated by gate voltage modulates the conductivity of ...Read more -
What Happens If You Use Too‑Large Gate Resistor on Anti‑Reverse MOSFET
Introduction P‑channel or N‑channel MOSFET is widely used for power‑supply reverse‑polarity protection. The gate resistor (Rg) is a simple yet critical component. Many designers pick a large resistor for safety, but oversized Rg brings several hidden reliability risks. 1. Extremely Slow Turn...Read more -
How to Select Gate Resistor for Anti-Reverse MOSFET？
Introduction The gate resistor is a simple yet critical component in anti-reverse MOS circuits. It controls gate charging/discharging speed, suppresses oscillation, and prevents false turn-on. Too small a resistor causes gate ringing and EMI noise; too large slows down MOS switching and may tr...Read more -
What is an Anti-Reverse MOSFET & Its Functions？
Intro Reverse current or reverse voltage surge is a common risk in power supply systems, battery packs and motor drive circuits. It may burn out control chips, damage batteries or trigger abnormal system shutdown. An anti-reverse MOSFET is a power MOSFET specially deployed to block reverse cur...Read more -
Gate Drive Circuits for High-Voltage MOSFETs
High-voltage MOSFETs (typically >200V, super-junction MOSFET widely used) cannot be directly driven by MCU GPIO pins. The floating high-side node, large gate charge Qg, strong Miller effect and high dv/dt are the main design challenges. A proper gate drive circuit is critical to avoid false t...Read more -
How Much Instantaneous Current Is Required to Turn On a MOSFET?
A common misunderstanding: MOSFETs are voltage-controlled devices. There is almost no continuous steady-state current at the gate (only nanoampere leakage current). The instantaneous current during turn-on is a pulsed peak current used to charge the gate parasitic capacitance. It only exists...Read more -
How to Test MOSFETs in Motor Controllers?
1. Preliminary Visual Inspection Check the appearance of the MOS tube first. Observe whether the chip surface is burnt, the pins are burned open‑circuit, the solder joints are cracked or the plastic package bulges. If obvious damage is found, the device is directly judged defective without fur...Read more -
How to Eliminate or Suppress the Miller Effect
The Miller effect comes from the parasitic Miller capacitance Cgd between gate and drain of MOSFET. During switching, the drain‑voltage swing couples current into the gate loop. It causes gate voltage platform (Miller plateau), slows switching speed, increases switching loss, may induce false tu...Read more -
Popular MOSFET Brands on the Market
1. Popular international brands 1.1 Infineon (Germany) 1.1.1 Strengths：The global top‑tier power semiconductor vendor. OptiMOS series for low‑voltage applications, CoolMOS super‑junction series for high‑voltage AC‑DC power supplies. Excellent consistency and reliability, full automotive‑gra...Read more -
Which Companies Lead in FET / MOSFET Technology？
1. International leading manufacturers 1.1 Infineon (Germany) Global top‑ranked power MOSFET supplier, full‑voltage‑range technology leader. Low‑&‑medium‑voltage：OptiMOS 5/6 SGT shield‑gate MOSFET, widely used for server power, automotive BMS, battery protection boards. Low \(R_{DS(o...Read more -
Two MOSFETs Connected in Series as Power Switch
1. Ordinary series connection (Drain‑to‑Source cascade) This topology connects the source of the first MOSFET to the drain of the second MOSFET. Both devices sit on the same current path. 1.1 Core purpose Increase the overall withstand‑voltage capability. When single‑device voltage rating ...Read more -
What Are the Functions of MOSFETs in Lithium‑ion Battery Protection Boards?
1. Over‑charge protection When the battery cell voltage rises to the over‑charge threshold after full charging, the protection IC sends a signal to turn off the charge MOSFET. The charging path is physically disconnected, and external power cannot continue to charge the battery. This prevent...Read more
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