DRIVING METHOD FOR STEPPING MOTOR

摘要

PURPOSE:To eliminate scattering of starting torque characteristic by a method wherein an axciting current in a one phase excitation period is generated not dependent on the high tension source during a period prior directly to the one phase excitation period. CONSTITUTION:A first monostable multivibrator MM1 generates a negative pulse upon receiving a negative signal tH while a second monostable multivibrator MM2 generates a negative pulse upon receiving a signal tL'. The two negative pulses go through an OR gate OR and reach the base input terminal tH' of a transistor TrQH. Turning on the transistor TrQH in the first two phase excitation period and in the roughly first half of the one phase excitation period with the transistor TrQL on causes a current to flow increasingly into a coil C. The means current flowing in the first two phase excitation period is smaller than the mean current in the one phase excitation period. Accordingly, the current in one coil during a one phase excitation period is made to approximtately match the sum of currents in two coils during a two phase excitation period.