Motor driving circuit
View Patent ↗A motor driving circuit for controlling a current amount flowing through a motor coil includes: a comparator configured to output a comparison signal indicating a comparison result between a set current amount and a current amount based on an inputted set current signal according to the set current amount and a current signal according to the current amount flowing through the motor coil; a current control signal update circuit configured to update a current control signal for controlling the current amount flowing through the motor coil in a stepwise manner so that the current amount flowing through the motor coil is changed to the set current amount in a stepwise manner, based on the comparison signal outputted from the comparator; and a driving circuit configured to drive the motor coil based on the current control signal outputted from the current control signal update circuit.
1. A motor driving circuit for controlling a current amount flowing through a motor coil, the motor driving circuit comprising:
a comparator configured to output a comparison signal indicating a comparison result between a set current amount and a current amount based on an inputted set current signal according to the set current amount and a current signal according to the current amount flowing through the motor coil;
a current control signal update circuit configured to update a current control signal for controlling the current amount flowing through the motor coil in a stepwise manner so that the current amount flowing through the motor coil is changed to the set current amount in a stepwise manner, based on the comparison signal outputted from the comparator; and
a driving circuit configured to drive the motor coil based on the current control signal outputted from the current control signal update circuit.
2. The motor driving circuit according to claim 1 , wherein
the current control signal update circuit includes:
an increase/decrease circuit configured to increase/decrease by a predetermined step size according to an inputted clock signal a control value for controlling the current amount flowing through the motor coil so that the current amount flowing through the motor coil is changed to the set current amount in a stepwise manner, based on the comparison signal outputted from the comparator; and
a step size control circuit configured to output the control value as the current control signal every time the control value outputted from the increase/decrease circuit is changed by a set step size, based on an inputted set step size signal according to the set step size.
3. The motor driving circuit according to claim 2 , wherein:
the comparator is further configured to output the comparison signal indicating a comparison result obtained by comparing for each bit between the set current amount indicated by the set current signal and the control value outputted from the increase/decrease circuit; and
the step size control circuit is further configured to output the control value as the current control signal every time the set current amount and the control value are equal to each other in lower bits of the bit number according to the set step size signal, based on the comparison signal outputted from the comparator and the set step size signal.
4. The motor driving circuit according to claim 3 , further comprising
a clock control circuit configured to stop generation of the clock signal when the current amount flowing through the motor coil reaches the set current amount based on the comparison signal outputted from the comparator.
5. The motor driving circuit according to claim 4 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.
6. The motor driving circuit according to claim 2 , further comprising
a clock control circuit configured to stop generation of the clock signal when the current amount flowing through the motor coil reaches the set current amount based on the comparison signal outputted from the comparator.
7. The motor driving circuit according to claim 6 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.
8. The motor driving circuit according to claim 2 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.
9. The motor driving circuit according to claim 3 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.
10. The motor driving circuit according to claim 1 , wherein
the current control signal update circuit includes:
an addition/subtraction circuit configured to add/subtract by a set step size based on an inputted set step size signal according to the set step size a control value for controlling the current amount flowing through the motor coil so that the current amount flowing through the motor coil is changed to the set current amount in a stepwise manner, based on the comparison signal outputted from the comparator; and
a latch circuit configured to latch according to an inputted clock signal the control value outputted from the addition/subtraction circuit and thereafter output the control value as the current control signal, and wherein
the comparator is further configured to output as the comparison signal a comparison result between the set current amount indicated by the set current signal and the current control signal outputted from the latch circuit.
11. The motor driving circuit according to claim 10 , further comprising
a clock control circuit configured to stop generation of the clock signal when the current amount flowing through the motor coil reaches the set current amount based on the comparison signal outputted from the comparator.
12. The motor driving circuit according to claim 11 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.
13. The motor driving circuit according to claim 10 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.
14. The motor driving circuit according to claim 1 , further comprising
a starter current control circuit configured to stop generation of a starter current for starting the driving circuit when the current amount flowing through the motor coil becomes zero based on the current control signal outputted from the current control signal update circuit.