The present invention discloses a brushless direct current motor driver. The brushless direct current motor driver comprises a DSP chip, the DSP chip is connected with a position estimation circuit, adriving chip, a difference current sampling circuit and a voltage collection and amplification circuit, the driving chip is connected with a bridge circuit, and the position estimation circuit, the bridge circuit, the difference current sampling circuit and a voltage sampling and amplification circuit are connected with a motor; the bridge circuit is a three-phase half-bridge circuit and is formed by 6 field effect transistors, each two of the field effect transistors is one half bridge, and one midpoint of each half bridge is connected with one phase of the motor; space vector pulse width modulation is performed in the DSP chip to convert square wave signals to sine wave signals for output; and PWM signals output after space vector pulse width modulation are acted on the three-phase half-bridge circuit through the driving chip and are finally taken as switching signals of the 6 field effect transistors, so as to allow the output current to be a sine wave current. The commutation process is smooth and steady, the noise is small, and the torque ripple is small.