Motor driving apparatus
AssigneePanasonic Corporation
InventorShuji Tamaoka
Life of this patent
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Abstract
There is provided a motor driving apparatus in which variations in individual circuit constants have a small effect even when a drive current is small. An error amplifier circuit amplifies a difference between a current detection signal showing a current value of a drive current that flows in the motor and a drive command signal controlling the drive current and converts an amplified difference into a current to output the current as an error amplifier current signal. A D/A conversion circuit generates a sinusoidal signal from the error amplifier current signal based on a digital signal sequence outputted from a rotational position detecting unit. It is preferable that a transfer coefficient of the error amplifier circuit is inversely proportional to the resistance value of the D/A conversion circuit.
Claims7
A motor driving apparatus comprising:
- a rotational position detecting unit that detects a rotational position of a motor to output a digital signal sequence according to the rotational position;
- a D/A conversion circuit that generates an analog sinusoidal signal based on the digital signal sequence;
- a drive circuit that generates and outputs a drive voltage to the motor by means of the sinusoidal signal;
- and
- an error amplifier circuit that amplifies a difference between a current detection signal showing a current value of a drive current that flows in the motor and a drive command signal for controlling the drive current, and converts the amplified difference into a current to output the current as an error amplifier current signal, wherein
- the D/A conversion circuit comprises a resistor, and
- a transfer coefficient of the error amplifier circuit is inversely proportional to a resistance value of the D/A conversion circuit.
Dependencies are inferred from the claim text.