Driving circuit for a stepping motor
AssigneeKabushiki Kaisha Daini Seikosha
InventorSatoshi Arai
Life of this patent
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Abstract
A driving circuit for a stepping motor has a pair of emitter-connected PNP transistors with the common junction point of the emitters connected to a source voltage. A pair of source-connected static induction transistors each has its drain connected to the collector of one PNP transistor with the connection point being connected to one side of the drive coil of the motor. The leak current characteristic of the static induction transistors along their drain-to-source paths is chosen so that sufficient leak current flows when all four transistors are simultaneously in the OFF state to effectively dampen the motor.
Claims5
A driving circuit for a stepping motor, comprising:
- first and second static induction transistors whose sources are connected together and each having a leak current characteristic between its drain and source selected so as to be approximately 10 .mu.A;
- first and second PNP transistors each having an emitter connected to a source voltage;
- and a motor having one terminal connected to a junction point of the drain of said first static induction transistor and the collector of said first PNP transistor and another terminal connected to a junction point of the drain of said second static induction transistor and the collector of said second PNP transistor.
In a driving circuit for stepwise driving a stepping motor having a drive coil:
- first and second bi-polar transistors having their respective emitters connected to a common junction point which is connectable to a source voltage during use of the driving circuit;
- first and second static induction transistors having their respective sources connected together;
- means connecting one end of the drive coil to a junction point of the collector of the first bi-polar transistor and the drain of the first static induction transistor and connecting the other end of the drive coil to a junction point of the collector of the second bi-polar transistor and the drain of the second static induction transistor;
- and wherein the first and second static induction transistors have a leak current characteristic in their respective drain-to-source paths when in the OFF state effective to dampen the motor when the first and second bi-polar transistors and the first and second static induction transistors are simultaneously all in the OFF state.
Dependencies are inferred from the claim text.