BYH31519_CEM4804 Introduction

So the stability of the tube is inseparable from the manufacturing process, and poor workmanship may result in the inconsistency of the parameters of these small tubes. Their various switching actions are almost the same. Of course, when they burn out, there must be a small tube that can't bear it first.

The MOS tube is a voltage-driven device. As long as an appropriate voltage is applied between the gate G and the source S, the conduction path between the source S and D will be formed. As the switch tube of the driving part, the main focus of the MOS tube is the withstand voltage, current withstand value and switching speed.

BYH31519_CEM4804

AO9926

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

BYS3105 BYP3105 BYJ31020A BYH31012A BYJ31012A BYP3104 BYF31010A BYP31013A BYS31010A BYH31055 .

However, in terms of structure, there is a big difference between them. In order to better understand the mechanism of power MOSFET, we must first recall the mechanism of low-power FET. . The following describes the principle of the MOS transistor with the structure of an N-channel enhancement type low-power MOSFET. Working principle of power MOS tube Power MOS tube is developed from low-power MOS tube.

BYP31538 BYP31510 BYP31575 BYH31574 BYD31523A BYH31532 BYM31580 BYH31519 BYS31535 BYM31545 .

BYH31519_CEM4804

4906

NCE3008M NCE3010S NCE3011E NCE30D0808J NCE3018AS.

NCE3075Q NCE3015S NCE3400E NCE3065K NCE3095AK.

The structure of the MOSFET shown in the figure is not suitable for use in high-power applications for two reasons. On the one hand, the three electrodes of the low-power MOSFET are on one plane, the channel cannot be made very short, and the channel resistance is large. On the other hand, the conductive channel is composed of surface induced charges, and the channel current is the surface current. To increase the current capacity, it is necessary to increase the chip area. Such a structure is unlikely to achieve a large current. .

The N-channel enhancement mode MOS transistor uses a low-doped P-type semiconductor as the substrate, and forms two heavily doped N+ regions on the substrate by a dispersed method, and then generates a very thin one on the P-type semiconductor. A silicon dioxide insulating layer, and then photolithography is used to etch away the silicon dioxide layer on the upper end of the two heavily doped N+ regions, exposing the N+ regions, and finally on the outer surface of the two N+ regions and the two between them. The surface of silicon oxide is sprayed with a layer of metal film by evaporation or sputtering. These three metal films constitute the three electrodes of the MOS tube, which are called source (S), gate (G) and drain (D) respectively. .

BYH31519_CEM4804

In the lithium battery protection board, the most important thing is to protect the chip and MOS tube.

The main functions of the lithium battery protection board are: 1 overcharge protection, 2 short circuit protection, 3 over current protection, 4 over discharge protection, 5 normal state.

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