Portable fan, drive circuit, handheld fan, and neck fan

A portable fan, comprising a fan and a power supply drive assembly electrically connected to the fan;

• wherein the power supply drive assembly comprises a battery and a fan drive circuit electrically connected to the battery;
• the fan drive circuit comprises:
• a master control circuit;
• a three-phase drive circuit, comprising at least three signal input ends and three drive signal output ends;
• wherein each of the at least three signal input ends is electrically connected to the master control circuit to receive control signals;
• each of the three drive signal output ends is electrically connect to a respective one of three signal ends of a direct-current (DC) brushless fan motor to respectively output a three-phase drive signal to drive the DC brushless fan motor to rotate;
• and
• an inverted-phase electric potential detection circuit, comprising three detection branches;
• wherein each of the three detection branches comprises a detection end and a detection output end electrically connected to the detection end;
• three detection ends of the three detection branches are respectively electrically connected to the three drive signal output ends;
• three detection output ends of the three detection branches are electrically connected to the master control circuit to respectively output a first detection signal, a second detection signal, and a third detection signal;
• the master control circuit is informed of a phase of the three-phase drive signal based on the first detection signal, the second detection signal, and the third detection signal to adjust the control signals;
• wherein the battery is configured to supply power to the fan drive circuit;
• wherein, the three-phase drive circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a ninth transistor;
• a first conductive end of the first transistor, a first conductive end of the second transistor, and a first conductive end of the third transistor are connected to a power supply end;
• a first conductive end of the fourth transistor is connected to the power supply end;
• a first conductive end of the fifth transistor is connected to the power supply end;
• a first conduction end of the sixth transistor is connected to the power supply end;
• a control end of the fourth transistor, a control end of the fifth transistor, and a control end of the sixth transistor are electrically connected to the master control circuit, a control end of the seventh transistor is electrically connected to the control end of the fourth transistor, a control end of the eighth transistor is electrically connected to the control end of the fifth transistor, and a control end of the ninth transistor is electrically connected to the control end of the sixth transistor, so as to receive the control signals;
• second conduction ends of the fourth transistor, the fifth transistor, and the sixth transistor are grounded;
• a first conductive end of the seventh transistor is connected to a second conductive end of the first transistor;
• a second conductive end of the seventh transistor is grounded;
• a first conductive end of the eighth transistor is connected to a second conductive end of the second transistor;
• a second conductive end of the eighth transistor is grounded;
• a first conductive end of the ninth transistor is connected to the second conductive end of the third transistor;
• a second conductive end of the ninth transistor is grounded;
• a node between the first conductive of the seventh transistor and the second conductive of the first transistor, a node between the first conductive of the eighth transistor and the second conductive of the second transistor, and a node between the first conductive of the ninth transistor and the second conductive of the third transistor respectively serve as the three drive signal output ends;
• the at least three signal input ends are three PWM signal input ends;
• the control signals comprise three PWM signals;
• and the fan drive circuit further comprises a current detection circuit;
• the second conductive ends of the seventh transistor, the eighth transistor, and the ninth transistor are all grounded via the current detection circuit;
• the current detection circuit is electrically connected to the master control circuit;
• the current detection circuit comprises a sense resistor and a sense capacitor;
• the second conductive ends of the seventh transistor, the eighth transistor, and the ninth transistor are grounded via the sense resistor and the sense capacitor sequentially;
• a node between the sense resistor and the sense capacitor is electrically connected to the master control circuit.