US 5,221,885 A · Low-power dual voltage drive circuit and method

Abstract

A low-power dual voltage drive circuit and method which includes controlling a stepper motor overdriven with a high voltage. The stepper motor drive circuit includes a high voltage supply for overdriving the stepper motor, a low voltage supply, and an overdrive switch mechanism connected between the high voltage supply means and the stepper motor input. The method includes repetitively triggering the overdrive switch in response to a control signal, overdriving the stepper motor with the high voltage, producing an overdrive current, sensing the overdrive current, producing an additional control signal when the overdrive current reaches a preset value, switching off the overdrive current in response to the second control signal, resetting the overdrive switch to enable the overdrive switch to again receive the first control signal, and driving the stepper motor with a nominal low voltage.

Claims12

Dependent claims

A method for overdriving with a high voltage a stepper motor driven at a nominal low voltage, the method comprising the steps of:

triggering a digital logic overdrive switch comprising a plurality of flip-flops coupled to an exclusive-or logic gate in response to a first digital control signal;
coupling the high voltage to the stepper motor through the digital logic overdrive switch;
overdriving the stepper motor with the high voltage, producing an overdrive current;
sensing the overdrive current through a resistor;
producing a second digital control signal when the overdrive current reaches a preset value;
switching off the digital logic overdrive switch and the overdrive current in response to the second digital control signal;
resetting the digital logic overdrive switch to enable the digital logic overdrive switch to receive the first digital control signal;
and
driving the stepper motor with the nominal low voltage.

6 more elements

A stepper motor drive circuit comprising:

high voltage supply means for overdriving a stepper motor in response to a first digital control signal to produce an overdrive current;
low voltage supply means;
stepper motor input means coupled to the low voltage supply means to drive the stepper motor at a nominal rate;
and
digital logic overdrive switch means coupled between the high voltage supply means and the stepper motor input means, wherein the digital logic overdrive switch means comprises a voltage divider carrying the overdrive current and a comparator coupled to the voltage divider to produce a second digital control signal when the overdrive current exceeds a predetermined value.

2 more elements

Dependencies are inferred from the claim text.

Low-power dual voltage drive circuit and method

Life of this patent

Low-power dual voltage drive circuit and method

Life of this patent

Abstract

Claims12