Over-voltage and under-voltage protection circuit of high-voltage bus power supply and distribution system for space navigation

The invention discloses an over-voltage and under-voltage protection circuit of a high-voltage bus power supply and distribution system for space navigation, which realizes an under-voltage and over-voltage protection locking function of a high-voltage bus input power distribution MOS (Metal Oxide Semiconductor) tube for space navigation. The circuit comprises an upper and lower limit voltage detection unit, a power distribution MOS tube on-off unit and a protection locking unit. The upper and lower limit voltage detection unit comprises a current-limiting resistor, a voltage regulation tube and a diode, and can generate an under-overvoltage protection signal input by a bus and transmit the under-overvoltage protection signal to the MOS tube on-off unit. The MOS tube on-off unit comprises a PMOS tube, a divider resistor and a driving triode, and can realize on and off of an input bus. The protection locking unit comprises a pair of NPN triodes and PNP triodes, the power distribution MOS tube is locked after a