Power supply system of vehicle-mounted communication device, vehicle-mounted communication device and power supply control method

Abstract

The invention relates to the technical field of vehicle power supply, in particular to a power supply system of a vehicle-mounted communication device, a vehicle-mounted communication device and a power supply control method. The power supply system comprises a first transistor Q1, a second transistor Q2 and a third transistor Q3; The first output terminal of the first transistor Q1 is connected with the electric quantity output terminal, and the second output terminal of the first transistor Q1 is connected with the first output terminal of the second transistor Q2. An input terminal of the second transistor Q2 is connected with a first output terminal of the third transistor Q3; As a result of that first transistor Q1, the second transistor Q2 and the third transistor Q3 constitute a power supply system of an on-board communication device, The invention realizes the seamless switching between the standby power supply and the main power supply, solves the problem of switching betweenthe two power supply systems, does not need MCU control such as single chip microcomputer, realizes automatic switching according to different external conditions, and has the advantages of low cost,stable performance and high reliability.

Description

technical field [0001] The invention relates to the technical field of power supply for vehicles, in particular to a power supply system of a vehicle communication device, a vehicle communication device and a power supply control method. Background technique [0002] New energy vehicles are the main development direction of today's automotive field. With the development of electronic technology, the reliability requirements for the power supply of vehicle communication devices (such as TBOX devices) are getting higher and higher, because vehicle communication devices need continuous power supply to output vehicle position information, monitoring and control information, vehicle communication devices All require uninterrupted power supply. Most uninterruptible power supply systems are composed of a main power supply and a backup power supply. After the main power supply fails, the electronic equipment can still work normally under the backup battery power supply. The switchi...

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Problems solved by technology

[0003] The traditional power switching scheme uses the single-phase conduction characteristic of the diode to switch the main power supply and the standby power supply, but the forward conduction voltage drop and forward conduction resistance of the diode make its work efficiency low, and the application cost is increased due to the increase of the diode. Increase

[0004] The other is a power switching scheme based on MOS (metal-oxide-semiconductor) switches, which utilizes the advantages of low conduction loss and easy integration of MOS tubes. This scheme gradually replaces the diode-based power switching scheme and becomes a power switching scheme. However, several problems inherent in the main and backup power switching schemes have not yet been resolved: first, when the high-voltage backup power is switched to the low-voltage main power, the system needs to have an active switching function, and the existing solutions are either only Which power supply is used to realize which voltage is higher, or the switching circuit is complicated; second, the substrate potential connection problem of the MOS switch tube, the existing scheme uses the substrate potential switching, this scheme is not only complicated and unstable, but also leads to electrostatic discharge performance This is due to the fact that the substrate potential of the switching MOS tube must be connected to the highest potential, so the substrate connection method of the MOS tube must be determined according to the voltage level of the two power supplies. After adopting this scheme, ESD and stability are greatly reduced; third, During the switching process of the main and backup power sources, the switch will oscillate back and forth; fourth, there is a risk of failure to power on normally

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