An excitation circuit for driving an excitation coil of a magnetic sensor, the excitation circuit comprising: a first transistor coupled between a first power supply node and a first end of the excitation coil; a second transistor coupled between the first power supply node and a second end of the excitation coil; a pulsed current source with a first terminal connected to the first power supply node and a second terminal alternately providing a first level of current and a second higher level of current; a current mirror circuit, including: an input transistor connected between the second terminal of the pulsed current source and a second power supply node; a third transistor connected between the first end of the excitation coil and the second power supply node; and a fourth transistor connected between the second end of the excitation coil and the second power supply node; and a control circuit operative to alternately couple one of the third and fourth transistors with the input transistor to mirror the second level of current from the pulsed current source to provide a periodic bidirectional excitation current waveform to the excitation coil, and characterized by a first switch coupled between a control terminal of the input transistor and a control terminal of the third transistor; and a second switch coupled between the control terminal of the input transistor and a control terminal of the fourth transistor; wherein the control circuit selectively operates the first and second switches to alternately couple one of the third and fourth transistors with the input transistor to mirror the second level of current from the pulsed current source to provide the periodic bidirectional excitation current waveform to the excitation coil. a first transistor coupled between a first power supply node and a first end of the excitation coil; a second transistor coupled between the first power supply node and a second end of the excitation coil; a pulsed current source with a first terminal connected to the first power supply node and a second terminal alternately providing a first level of current and a second higher level of current; a current mirror circuit, including: an input transistor connected between the second terminal of the pulsed current source and a second power supply node; a third transistor connected between the first end of the excitation coil and the second power supply node; and a fourth transistor connected between the second end of the excitation coil and the second power supply node; and a control circuit operative to alternately couple one of the third and fourth transistors with the input transistor to mirror the second level of current from the pulsed current source to provide a periodic bidirectional excitation current waveform to the excitation coil, and characterized by a first switch coupled between a control terminal of the input transistor and a control terminal of the third transistor; and a second switch coupled between the control terminal of the input transistor and a control terminal of the fourth transistor; wherein the control circuit selectively operates the first and second switches to alternately couple one of the third and fourth transistors with the input transistor to mirror the second level of current from the pulsed current source to provide the periodic bidirectional excitation current waveform to the excitation coil.