Auxiliary power supply protection circuit and auxiliary power supply

The utility model belongs to the technical field of power supply protection circuits, and particularly relates to an auxiliary power supply protection circuit and an auxiliary power supply. The protection circuit comprises an under-voltage protection module, and the under-voltage protection module comprises a control chip and a first voltage dividing branch. The control chip is used for connecting a controlled end of a control switch of the auxiliary power supply. The first voltage dividing branch is used for being connected between an input end of the auxiliary power supply and the ground. A first voltage dividing unit and a second voltage dividing unit are sequentially connected in series on the first voltage dividing branch from the input end of the auxiliary power supply to the ground, voltage dividing points of the first voltage dividing unit and the second voltage dividing unit are connected with the power supply end of the control chip, and the resistance value of the first voltage dividing unit needs