BYP6662_DMN4031SSD-13 Introduction

The power mos used on electric vehicles is a three-dimensional structure. The mos tube we have seen is actually composed of thousands of small mos tubes in parallel. You may think that one or a few bad moss should easily appear in thousands of small mos. In fact, it is not that easy. , the current manufacturing process basically guarantees the high consistency of various parameters of these small units. Low-power mos is a planar structure.

The resistance of this current path is called the internal resistance of the MOS tube, that is, the on-resistance. The size of this internal resistance basically determines how much on-current the MOS tube chip can withstand (of course, it is related to other factors, such as thermal resistance). The smaller the internal resistance, the larger the current (because the heat is small).

BYP6662_DMN4031SSD-13

SI9926BDY-T1-E3

BYC4322 BYM4310 BYM4322 BYM4316 BYC4312 BYM438 BYS441 BYN4458 BYE4625Z BYM4612 .

. 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.

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.

BYP6662_DMN4031SSD-13

DMN3024LSD-13

BYN31028Z BYN31024A BYG31013A BYN31095 BYJ31040 BYM31013A BYH31015-X BYH31015 BYS31030 BYF31040

When the low UDS separate pinch off voltage is large, the MOS tube is equivalent to a resistance, and this resistance decreases with the increase of UGS. Cut-off area (UGS). Growth slows as the conduction channel approaches pinch off. Figure 1. Drain output characteristics of MOS transistors The output characteristics of field effect transistors can be divided into four regions: variable resistance region, cut-off region, breakdown region and constant current region. Variable resistance region (UDS In this region, ID increases linearly as UDS increases.

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 characteristics of a MOSFET can be characterized by a transfer characteristic curve and a drain output characteristic curve. Figure 3 shows the handling characteristics of a certain FET. The transfer characteristic refers to the relationship curve between the gate voltage UGS and the corresponding drain current ID when the voltage UDS between the drain and the source is at a certain fixed value.

BYP6662_DMN4031SSD-13

The functions of the MOS tube in the protection board are: 1. Detect overcharge, 2. Detect over-discharge, 3. Detect over-current during charging, 4. Detect over-current during discharge, 5. Detect over-current during short circuit.

NCE25TD135LP NCE1608N NCE18ND11U NCE3134 NCE20ND07U.

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