Motor control circuit

A motor control circuit for controlling operation of a reversible motor having a shaft and motor control windings comprising:

• position transducer means coupled to said motor shaft for providing an output electrical signal proportional to a displacement of said motor shaft from a reference motor shaft position;
• comparator means having first and second input terminals and an output terminal, said comparator means being arranged to compare magnitude of a reference signal coupled to said comparator first input terminal with magnitude of said position transducer output electrical signal coupled to said comparator second input terminal to provide a motor direction control signal;
• feedback means coupled between said comparator second input terminal and said comparator output terminal to cause said comparator means to oscillate to stop said motor operation when a difference in magnitude between said reference and transducer electrical signals is substantially equal to a predetermined magnitude;
• motor direction control means coupled between said comparator output terminal and said motor control windings, said motor direction control means being arranged to generate motor control signals for controlling said motor operation in response to said comparator means output signal, said motor direction control means having forward direction control means with an input terminal coupled to said comparator means output terminal and an output terminal coupled to a first end of said motor control windings, said forward direction control means responding to said comparator means output signal to operate said motor to rotate said shaft in a forward direction;
• and
• reverse direction control means having an input terminal coupled to said comparator means output terminal and an output terminal coupled to a second end of said motor control windings, said reverse direction control means responding to said comparator means output signal to operate said motor to rotate said shaft in a reverse direction.