Browse Prior Art Database

Pulse Width Modulation Motor Drive Circuit

IP.com Disclosure Number: IPCOM000116327D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Enami, K: AUTHOR

Abstract

Disclosed is a circuit for Pulse Width Modulation (PWM) motor drive which has a pulse distributing means for the coil current switching. This circuit can reduce acoustic noise of the PWM motor.

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Pulse

Width Modulation Motor Drive

Circuit

      Disclosed is a circuit for Pulse Width Modulation (PWM) motor
drive which has a pulse distributing means for the coil current
switching.  This circuit can reduce acoustic noise of the PWM motor.

      Fig. 1 shows a block diagram of the brushless spindle motor
driver.  This driver has sensorless PWM drive means.  Pulse width of
Q2, Q4, Q6 controls drive current.

      Fig. 2 shows timing chart of the driver.  And Fig. 3 shows
timing expanded chart at a current switching point, Part S, in Fig.
2.  At this switching point, current pulse supply is changed from
OUTPUT U to OUTPUT V.  The current pulses are shared and distributed
to both OUTPUT U and V in a certain period.

      Signal P0, P1, and A - E and comments in Fig. 3 show how to
make Q2 and Q4 gate signal, F and G.

      In this circuit, current pulses are shared fifty-fifty in a
certain period.  However, this current pulse density can be changed
more linearly by the logic arrangement.