Browse Prior Art Database

H Driver Circuit for Stepper Motor

IP.com Disclosure Number: IPCOM000052482D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Nebgen, GB: AUTHOR

Abstract

The present circuit is an improvement in the H-driver circuits used to reverse phase in stepper motor windings. Through the expedient of cross-coupling of the pair of drive transistors for the motor windings, the circuit improvement eliminates a pair of gates which were previously used.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 78% of the total text.

Page 1 of 2

H Driver Circuit for Stepper Motor

The present circuit is an improvement in the H-driver circuits used to reverse phase in stepper motor windings. Through the expedient of cross-coupling of the pair of drive transistors for the motor windings, the circuit improvement eliminates a pair of gates which were previously used.

A typical H-driver circuit is shown in Fig. 1 for one phase of a bipolar stepper motor. This circuit employs discrete transistors for carrying motor current and logic gates for switching current through the appropriate devices. The motor is stepped by passing current through the windings in either direction.

When line A is high, G1 turns on Q1, and G4 turns on Q4. The motor current thus moves from left to right. When A is low, G2 turns on Q2, and G3 turns on Q3. This causes motor current in the right-to-left direction. Acceptable combinations are: both Q1 and Q4 on or both Q2 and Q3 on.

This article is based on the gate reduction afforded when the circuit of Fig. 1 is reconfigured as shown in Fig. 2. Note that gates G1 and G2 are eliminated. In this circuit, Q4 is switched on just as before by G4, but now Q4 supplies the low level signal which turns on Q1 at the same time. This combination gives left- to-right current as before. Also, as before, Q3 is controlled by G3, but Q3 now controls Q2. This circuit is functionally equivalent to the circuit in Fig. 1 but uses two less gates.

A further reduction can be implemented if the motor currents are l...