Stepping Motor Drive Circuit
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
This high efficiency drive circuit for a stepping motor is characterized in that a counter-electromotive force produced in a coil at the phase switching serves to drive the other coil without any delay. Fig. 1 shows the circuit, and Fig. 2 shows the potentials at some specified points in the circuit. Its operation is as follows: 1. At t1 time, transistors Tr1 and Tr2 are switched from OFF to ON and from ON to OFF, respectively. Condenser C is charged by the counter-electromotive force of coil L2. On charging the condenser C, a current flows via resistor R, diode D2, coil L2, diode D4, coil L1 and transistor Tr1, so that the current in coil L1 increases to drive the coil L1 while the current in coil L2 decreases. 2. At t2 time, the current in coil L2 becomes zero.