Pulse motor driver

• US 5,563,486 A
• Filed: 12/23/1994
• Issued: 10/08/1996
• Est. Priority Date: 12/24/1993
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Miyake, Tukasa, Ban, Hiroyuki, Kataoka, Masami, Hayakawa, Junji, Yamamoto, Tomohisa
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US08/362,933
• Time in Patent Office: 655 Days
• Field of Search: 318/685, 318/696, 318/138, 318/139, 318/254, 318/439, 318/701
• US Class Current: 318/696
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence
• CPC Class Codes: H02P 8/18 Shaping of pulses, e.g. to reduce torque ripple
• CPC Class Codes: H02P 8/32 Reducing overshoot or oscillation, e.g. damping

Abstract

A driving circuit of a pulse motor for use in a vehicle odometer is provided. The driving circuit includes a pulse source for providing drive pulses, in sequence, to a plurality of phase coils of the pulse motor, and a wave-shaper for shaping leading and trailing edges of each of the drive pulses so as to vary at a given rate in plural steps for noiseless smooth rotation of the pulse motor.

Claims

1. A driving apparatus for a pulse motor for use in a vehicle comprising:

a plurality of switching elements, having resistors, each disposed on an exciting line communicating in series with a corresponding one of a plurality of phase coils of the pulse motor;

switching control means for controlling switching operations of said switching elements, said switching control means being responsive to input of excitation signals provided based on a given input signal to the phase coils to energize said switching elements, in sequence, for establishing electrical communications to supply the excitation signals to the phase coils;

canceling signal output means for outputting a canceling signal to cancel a sequential communication operation of said switching control means when a voltage provided by said given input signal exceeds a preselected voltage level; and

switching means, responsive to the canceling signal from said canceling signal output means, for canceling the sequential communication operation of said switching control means to input a given excitation signal to at least one of the phase coils of the pulse motor.

2. A driving apparatus for a pulse motor for use in a vehicle comprising:

a plurality of transistors connected in parallel with each other, said transistors having given resistances each leading to a corresponding one of a plurality of phase coils of the pulse motor;

a plurality of flip-flops connected in series with each other, said flip-flops communicating through a logic circuit with said transistors, respectively, for energize said transistors in sequence according to a variation in an input signal;

a frequency-voltage converter circuit provided prior to said flip-flops to convert the input signal into a voltage signal;

a comparator provided prior to said flip-flops to compare the voltage signal from said frequency-voltage converter circuit with a preselected threshold voltage to output a canceling signal to the logic circuit when the voltage signal exceeds the preselected threshold voltage for canceling sequential communication operations of said transistors while energizing at least one of said transistors to establish the electrical communication thereof.

3. A driving apparatus for a pulse motor comprising:

pulse source means for providing drive pulses, in sequence, to a plurality of phase coils of the pulse motor; and

wave-shaping means for shaping the drive pulses provided from said pulse source means to the phase coils of the pulse motor, said wave-shaping means modifying leading and trailing edges of each of the drive pulses so as to vary at a given rate in plural steps, wherein said wave-shaping means includes a switching circuit for each phase coil, each of the switching circuits switching between first and second switching modes according to a given input signal, the first switching mode being established to vary the leading and trailing edges of each of the drive pulses in the plural steps when the given input signal is greater than a preselected value and it is required to rotate the pulse motor at a lower speed, the second switching mode being established to vary the leading and trailing edges of each of the drive pulses in one step when the given input signal is smaller than the preselected value and it is required to rotate the pulse motor at a higher speed.

4. A driving apparatus for a pulse motor comprising:

pulse source means for providing drive pulses, in sequence, to a plurality of phase coils of the pulse motor; and

wave-shaping means for shaping the drive pulses provided from said pulse source means to the phase coils of the pulse motor, said wave-shaping means modifying leading and trailing edges of each of the drive pulses so as to vary at a given rate in plural steps, wherein said wave-shaping means selects between first and second wave-shaping modes, the first wave-shaping mode being to set first portions of the leading and trailing edges of each of the drive pulses to a first level, the second wave-shaping mode being to set second portions continuing from the first portions of the leading and trailing edges of each of the drive pulses to a second level higher than the first level.