STS8205 Introduction

Today I will introduce to you a domestic FET that is suitable for lithium battery protection boards and can replace MOS tubes such as AO3401: NCE3401.

The core of power semiconductors is the PN junction. From diodes, triodes to field effect transistors, various applications are made according to the characteristics of the PN junction. According to whether the inversion layer exists in the case of no electricity, MOS tubes can be divided into enhancement type and depletion type. Field effect transistors are divided into junction type and insulated gate type, among which the insulated gate type is also called MOS tube (Metal Oxide Semiconductor).

AP9926EM_P2804HVG&Special 30V

STS8205

. The conductive channel of the MOS tube can be formed during the production process or by turning on an external power supply. When the gate voltage is equal to zero, there is a channel (that is, formed during production), which is called depletion mode. When an external voltage is applied The one that forms the channel later is called the enhancement type.

Power MOSFETs are generally rarely used in P-channel. Since the mobility of holes is lower than that of electrons, the on-resistance of P-channel transistors is larger than that of N-channel transistors for the same channel size. According to the two points of the conductive channel and the process of channel formation, MOS tubes can be divided into: P-channel enhancement MOS tubes, P-channel depletion MOS tubes, N-channel enhancement MOS tubes and N-channel depletion MOS tubes . . Figure four types of MOSFETs and their graphical symbols.

For these two enhanced MOS tubes, NMOS is more commonly used. . As for why not to use depletion-type MOS tubes, it is not recommended to get to the bottom of it.

NCE3019AS NCE3045G NCE3400AY NCE30ND07S NCE8601B.

AP9926EM_P2804HVG&Special 30V

STS8205

When the applied forward voltage increases, the concentration of unbalanced minority carriers increases and the concentration gradient also increases, and when the applied voltage decreases, the change is opposite. Diffusion capacitance: When a forward voltage is applied, the non-equilibrium minority carrier concentration near the interface of the depletion layer is high, far from the non-equilibrium minority carrier concentration is low, and the concentration gradually decays from high to 0 until it reaches zero. The process of charge accumulation and release in this phenomenon is the same as that of capacitor charging and discharging, which is called diffusion capacitance.

NCE3020K NCE3025Q NCE3035K NCE3025G NCE3030K.

NCE6802 NCE30H29D NCEB301Q NCEB301Q NCEB301G.

The full area (UDS>UGS-UT) guarded in the above three areas is the full area, also known as the constant current area or the amplification area. When the UDS increases to a certain value, the drain PN junction breaks down, the leakage current increases rapidly, and the curve turns upward and enters the breakdown region. . Power MOSFETs are used in power conversions such as switching power supplies and inverters, and they work in two regions, the cut-off region and the breakdown region. The breakdown region is in the region of considerable drain-source voltage UDS, and the drain current is approximately constant.

AP9926EM_P2804HVG&Special 30V

NCE25TD120WT NCE25TD120VT NCE15TD120LT NCE25TD120LT NCE40TD135LT.

The lithium battery is mainly composed of two blocks, the battery cell and the lithium battery protection board PCM.

relevant information