Motor control circuit for regulating a D.C. motor

A direction control oscillator for generating motor control signals indicating if a motor rotor should operate in a forward state, a reverse state or oscillate between the forward and reverse states, said direction control oscillator including:

• a first logic circuit connected to receive a first user-generated direction signal indicating that the motor should operate in the forward state and a second user-generated direction signal indicating that the motor should operate in the reverse state, said first logic circuit configured to generate a MOTOR.sub.-- ENABLE signal when either the first user-generated direction signal or the second user-generated direction signal is received;
• a second logic circuit connected to receive the first user-generated direction signal and the second user-generated direction signal, said second logic circuit configured to generate a FORWARD/REVERSE signal wherein:
• when only the first user-generated direction signal is received, a FORWARD/REVERSE state signal is generated;
• when only the second user-generated signal is received, a FORWARD/REVERSE state signal is generated;
• and, when both the first and second user-generated direction signals are received, the FORWARD/REVERSE signal is cyclically transitioned between the FORWARD/REVERSE state signal and the FORWARD/REVERSE state signal;
• and
• a third logic circuit connected to receive the first and second user-generated direction signals and the MOTOR.sub.-- ENABLE signal, said third logic circuit configured to selectively forward the MOTOR.sub.-- ENABLE signal or a MOTOR.sub.-- ENABLE signal, wherein, when both the first and second user-generated direction signal are received, after each state transition of the FORWARD/REVERSE signal, said third logic circuit forwards the MOTOR.sub.-- ENABLE signal for a select period of time before forwarding the MOTOR.sub.-- ENABLE signal.

A motor driver circuit for a motor having a plurality of windings and, a rotor, wherein the motor generates a plurality of pulsed signals that are representative of the rotational position of the rotor, said driver circuit including:

• a first gate array for receiving the pulsed signals from the motor, a MOTOR.sub.-- ENABLE signal indicating that the motor is to be actuated and a BRAKE.sub.-- ON signal indicating that the motor is to be braked, said first gate array configured to sequentially assert a plurality of HIGH.sub.-- DRIVER signals to cause the motor windings to be individually tied to a power supply when the MOTOR.sub.-- ENABLE signal and a BRAKE.sub.-- ON signal are received, wherein said first gate array sequentially asserts the HIGH.sub.-- DRIVER signals based on the state of the pulsed signals;
• a second gate array for receiving the pulsed signals from the motor, the MOTOR.sub.-- ENABLE signal and a pulse width modulated SPEED.sub.-- CONTROL signal, said second gate array configured to sequentially assert variable LOW.sub.-- DRIVER signals that have a variable on duty-cycle to tie the motor windings to ground when the MOTOR.sub.-- ENABLE signal is asserted, wherein said second gate array asserts the LOW.sub.-- DRIVER signals individually based on the state of the pulsed signals, and so that the on duty-cycle of the LOW.sub.-- DRIVER signals is a function of the duty cycle of the SPEED.sub.-- CONTROL signal.

An integrated circuit for regulating the operation of a motor having a variable speed rotor, a plurality of windings that are selectively tied to a power source or ground, wherein the motor generates at least one pulsed signal representative of the rotational position of the rotor, said integrated circuit comprising:

• a tachometer for receiving the pulsed signal from the motor said tachometer including:
• a current source;
• a switch array for selectively tieing a first capacitor to said current source or ground, wherein said switch array is configured to tie the capacitor to the current source for a fixed period of time after each pulsed signal is received;
• and
• a first pulse generator connected to the first capacitor for producing TACHOMETER.sub.PWM pulses as a function of the voltage across the capacitor;
• a pulse width modulator including:
• an amplifier having a first input to which integrated TACHOMETER.sub.PWM pulses are applied, a second input to which an analog, user-set USER.sub.-- SPEED signal is applied, said amplifier producing a SPEED.sub.-- CONTROL signal as a function of the difference between the USER.sub.-- SPEED signal and the integrated TACHOMETER.sub.PWM pulses;
• and
• a second pulse generator connected to the amplifier for receiving the SPEED.sub.-- CONTROL signal, said second pulse generator configured to produce a pulsed SPEED.sub.-- CONTROL.sub.PWM signal, wherein the SPEED.sub.-- CONTROL.sub.PWM signal has an on duty-cycle proportional to the magnitude of the SPEED.sub.-- CONTROL signal;
• and
• a motor driver responsive to the SPEED.sub.-- CONTROL.sub.PWM signal and the pulsed signal from the motor for sequentially asserting HIGH.sub.-- SIDE.sub.-- CONTROL signals to tie the windings of the motor to a power source and variable on duty-cycle LOW.sub.-- SIDE.sub.-- CONTROL signals to tie the windings of the motor to ground, wherein, said motor driver sequentially asserts the HIGH.sub.-- SIDE.sub.-- CONTROL and the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the pulsed signal and varies the on duty-cycle of the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the on duty-cycle of the SPEED.sub.-- CONTROL.sub.PWM signal.

An integrated circuit for regulating the operation of a motor having a rotor and a plurality of windings that are selectively tied to a power source or ground, said integrated circuit comprising:

• a pulse width modulator for receiving a signal representative of the speed of the motor rotor and an analog, user-set USER.sub.-- SPEED signal, said pulse width modulator configured to produce a pulse width modulated SPEED.sub.-- CONTROL.sub.PWM signal that has an on duty-cycle that varies as a function of the speed of the motor and the USER.sub.-- SPEED signal;
• a forward/reverse controller for receiving a user-set forward signal when the motor is to be run in a forward direction and a user-set reverse signal when the motor is to be run in a reverse direction, wherein, said forward/reverse controller is configured to assert a MOTOR.sub.-- ENABLE signal when either the forward signal or the reverse signal is received and a FORWARD/REVERSE signal, the FORWARD/REVERSE signal being in a FORWARD/REVERSE signal state when the forward signal is received and in a FORWARD/REVERSE signal state when the reverse signal is received and, wherein:
• when both the user-set forward signal and the user-set reverse signal are received, said forward/reverse controller causes the FORWARD/REVERSE signal to cyclically transition between the FORWARD/REVERSE signal state and the FORWARD/REVERSE signal state;
• and
• said forward/reverse controller is further configured to receive a motor speed signal indicating if the motor rotor is turning and, when both the user-set forward signal and the user-set reverses signal are received, with each signal state transition of the FORWARD/REVERSE signal, said forward reverse controller asserts a MOTOR.sub.-- ENABLED signal until the rotor speed signal indicates that the motor rotor has stopped turning;
• and
• a motor driver responsive to the SPEED.sub.-- CONTROL.sub.PWM signal and a signal representative of the rotational position of the motor rotor for sequentially asserting HIGH.sub.-- SIDE.sub.-- CONTROL signals to tie the windings of the motor to a power source and LOW.sub.-- SIDE.sub.-- CONTROL signals that have a variable on duty-cycle to tie the windings of the motor to ground, wherein, said motor driver sequentially asserts the HIGH.sub.-- SIDE.sub.-- CONTROL and the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the rotational position of the motor rotor and varies the on duty-cycle of the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the on duty-cycle of the SPEED.sub.-- CONTROL.sub.PWM signal and wherein said motor driver receives the MOTOR.sub.-- ENABLE signal and the FORWARD/REVERSE signal and is further configured to inhibit assertion of the HIGH.sub.-- SIDE.sub.-- CONTROL signals when a MOTOR.sub.-- ENABLE signal is received and further regulates the sequence in which the HIGH.sub.-- SIDE.sub.-- CONTROL and the LOW.sub.-- SIDE.sub.-- CONTROL signals are asserted as a function of the state of the FORWARD/REVERSE signal.

An integrated circuit for regulating the operation of a motor having a rotor and a plurality of windings that are selectively tied to a power source or ground, said integrated circuit comprising:

• a pulse width modulator for receiving a signal representative of the speed of the motor rotor and an analog, user-set USER.sub.-- SPEED signal, said pulse width modulator configured to:
• produce a pulse width modulated SPEED.sub.-- CONTROL.sub.PWM signal that has a variable on duty-cycle that varies as a function of the speed of the motor and the USER.sub.-- SPEED signal;
• and
• to produce a BRAKE signal whenever the speed of the rotor is exceeding the user-set speed by a selected amount;
• and
• a motor driver responsive to the SPEED.sub.-- CONTROL.sub.PWM signal, the BRAKE signal and a signal representative of the rotational position of the motor rotor for sequentially asserting HIGH.sub.-- SIDE.sub.-- CONTROL signals to tie the windings of the motor to a power source and LOW.sub.-- SIDE.sub.-- CONTROL signals that have a variable on duty-cycle to tie the windings of the motor to ground, wherein, said motor driver sequentially asserts the HIGH.sub.-- SIDE.sub.-- CONTROL and the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the rotational position of the motor rotor and varies the on duty-cycle of the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the on duty-cycle of the SPEED.sub.-- CONTROL.sub.PWM signal and wherein, when said motor driver receives the BRAKE signal, said motor driver selectively asserts and negates the HIGH.sub.-- SIDE.sub.-- CONTROL and the LOW.sub.-- SIDE.sub.-- CONTROL signals to cause braking of the motor rotor.