The utility model relates to a power
supply management circuit of a motor mainboard, which comprises a power supply conversion circuit, a battery power supply
control circuit and a button detection circuit, the power supply conversion circuit is connected with an input
voltage VBAT, the battery power supply
control circuit is connected with the input
voltage VBAT, and the button detection circuit is connected with the battery power supply
control circuit. The power conversion circuit is used for converting an input
voltage VBAT into 3.3 V, the battery power supply control circuit is used for controlling on and off of battery power supply through a BATEN
signal, and when the BATEN is at a high level, Q3 is conducted, the base voltage of Q4 is lowered and
cut off, so that the enable end of the DC-
DC converter is closed, and VBAT output is stopped; and the key detection circuit feeds back the key condition to the KEYWKUP through the SW1 key and outputs a high-level or low-level
signal to judge the state of the key at the moment. According to the utility model, the input voltage VBAT can be efficiently and stably converted into 3.3 V through the power conversion circuit, so that the requirement of a motor mainboard on stable working voltage is met, and the stability of circuit operation is improved.