Vehicle-mounted high-side switch

Abstract

The invention relates to a vehicle-mounted high-side switch which comprises a controller, a MOS main switching tube driving circuit, a MOS main switching tube, a detection circuit, a logic circuit anda MOS tube follow current circuit. An input end of the MOS main switching tube is used for being connected with an external power supply. An input end of the detection circuit is electrically connected with an output end of the MOS main switching tube. A first output end of the controller is electrically connected with an input end of the MOS main switching tube driving circuit, and the output end of the MOS main switching tube is used for being connected with an electric heating element of a vehicle-mounted preheater. The MOS tube follow current circuit comprises a plurality of follow current MOS tubes connected in parallel with each other. First conduction ends of the plurality of follow current MOS tubes are all connected to the output end of the MOS main switching tube, and second conduction ends of the follow current MOS tubes are all grounded. An input end of the logic circuit is electrically connected with a second output end of the controller, and an output end of the logic circuit is respectively and electrically connected with control ends of the plurality of follow current MOS tubes. According to the invention, when the MOS main switching tube has a failure, the MOS main switching tube can be burnt down so as to protect the vehicle-mounted preheater from being burnt down.

Description

technical field [0001] The invention relates to automotive electronic technology, in particular to a high-side switch for controlling the power supply of a vehicle-mounted preheater. Background technique [0002] figure 1 A schematic block diagram of an existing on-board high-side switch is shown. The existing vehicle-mounted high-side switch 100 is mainly composed of a power supply circuit 91, a controller 92, a MOS main switch drive circuit 93 and a MOS main switch 94, and is mainly used to control the work of the vehicle-mounted preheater. Wherein, the vehicle battery 7 is electrically connected with the input end of the power supply circuit 91 and the input end of the MOS main switch tube 94 respectively, the output end of the power supply circuit 91 is electrically connected with the power supply input end of the controller 92, and the output end of the controller 92 is electrically connected with the MOS The input end of the main switch tube drive circuit 93 is elect...

AI Technical Summary

Problems solved by technology

Due to the risk of failure of the MOS main switch tube 94, once the MOS main switch tube 94 fails, the on-board preheater will continue to heat up, which will not only burn the on-board preheater, but also burn down other equipment on the car, which poses a great safety hazard

[0005] In order to detect whether the MOS main switching tube 94 fails, as figure 1 As shown, some vehicle-mounted high-side switches currently on the market are provided with a detection circuit 95 for detecting whether there is an output current in the MOS main switch tube 94. Although the controller 92 can determine that the MOS main switch tube is 94 is invalid, but it cannot automatically prevent the electric heating element of the vehicle preheater from continuing to heat, and the safety hazard caused by the failure of the MOS main switch tube 94 has not been completely resolved

Images