Adaptive series circuit with metal oxide semiconductor (MOS) transistors

Abstract

The invention discloses an adaptive series circuit with metal oxide semiconductor (MOS) transistors. The on-off motion of a master control MOS transistor is controlled to correspondingly control the adaptive on-off motion of the other MOS transistors, and the MOS transistors are ensured to work safely by utilizing a clamping circuit. The maximum withstand voltage of an equivalent MOS transistor consisting of the MOS transistors is the sum of maximum withstand voltages of all the series-connected MOS transistors. In an actual manufacturing process, limitation on the number of the series-connected MOS transistors is avoided on the premise of not exceeding maximum voltage between the drain of the equivalent MOS transistor and a substrate, so that the limitation of a process on the maximum withstand voltage range of the obtained equivalent MOS transistor is avoided. The adaptive series circuit is applied to places such as a switching regulator and the like requiring quick switching and places such as a light-emitting diode (LED) driving circuit and the like with low requirement for switching speed, and also can be applied to circuits such as a high-voltage step-up regulator, a step-down regulator, a linear regulator and the like.

Description

technical field [0001] The invention relates to a series circuit of MOS tubes, in particular to an adaptive series circuit of MOS tubes. Background technique [0002] At present, the series connection technology of MOS transistors is mainly used to increase the maximum output impedance of the equivalent MOS transistors after series connection, but does not increase its maximum withstand voltage capability. figure 1 Shown is a functional block diagram of connecting two MOS transistors in series in the prior art, wherein the voltage at point A is the sum of the gate-source voltages of MOS transistors 101 and 102, and the increase of the equivalent impedance after the MOS transistors 101 and 102 are connected in series makes The output current at point B has nothing to do with the voltage at this point, but the maximum withstand voltage of the equivalent MOS tube after series connection has not increased. Therefore, the application of MOS tubes in many high-voltage application...

AI Technical Summary

Problems solved by technology

Therefore, the application of MOS tubes in many high-voltage applications is limited, such as figure 2 As shown, it is a functional block diagram of a high-voltage switching regulator, in which the switching tube Q needs to withstand a certain high voltage when it is turned off, but can still work safely. At this time, a MOS tube with a large withstand voltage parameter is selected as the switching tube Q. It is very convenient, but the cost is high. In practical applications, the maximum withstand voltage of the existing MOS tube is limited by the production process and sometimes cannot meet the needs

Images