The invention discloses a pre-
driving circuit of a single-phase brushless
direct current motor, which is characterized in that a pre-driver does not directly output GP1, but directly controls the on and off of a second PMOS (P-channel
Metal Oxide Semiconductor) tube through the cooperation of a first driving pin FG and a first
resistor between the source
electrode and the grid
electrode of the second PMOS tube, and meanwhile, the on and off of the second PMOS tube are controlled through the cooperation of the first driving pin FG and the first
resistor; on and off of the first PMOS tube are controlled by a first
resistor between the source
electrode and the grid electrode of the third NMOS tube and the source electrode and the grid electrode of the first PMOS tube, so that a GP1 pin and a corresponding
driving circuit on the pre-driver are reduced, and furthermore, GN1 and GN2 drive the two NMOS tubes respectively while the GN1 and GN2 drive the two NMOS tubes respectively. When an upper tube and a lower tube of a preceding stage GN1 / GN2 are both turned off,
voltage drop on a third resistor is indirectly sampled through a second resistor between a source electrode and a grid electrode of the preceding stage GN1 / GN2, that is, current sampling is completed by
multiplexing GN1 / GN2, so that CS pins on a pre-driver are reduced; therefore, the number of pins of the pre-driver and board-level connecting lines are reduced while the driving and current detection functions are reserved, and then the packaging cost of the pre-driver is optimized.