Motor control device

#The present invention relates to a microprocessor and, more particularly, to a micro-processing control device of a motor.

#Along with progress of high scientific technology, the development of many electronic products tends to multi-functionality and miniaturization. Therefore, for many motor-driven electronic products like recorders, compact disk players, and digital still cameras, the miniaturization and multi-functionality of the motor control device and driver have become important issues in motor design.

#In the control device of a common motor, in consideration of the requirements of forward rotation, reverse rotation, and braking of the motor, three signal input pins are required in an IC chip to provide signals for forward rotation, reverse rotation, and braking, respectively. With also a power input, a ground, a positive electrode and a negative electrode of the motor, and control signals, the whole motor control circuit at least requires eight pins in the IC chip so that the volume of the manufactured IC chip will be too large and cannot meet the requirement of miniaturized electronic products. Besides, in order that the rotation speed of an operating motor can be detected and adjusted, the control device is usually electrically connected to a Hall effect device. In addition to the design of the above signal control device and the Hall effect device, it is also necessary to arrange a drive current switch like a MOSFET in the motor to provide a power source for the motor. Because the components are complicated and the MOSFET is bulkier, the above conventional design cannot apply to drive and control components of motor in common miniaturized products, i.e., the practical value is low.

#The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:

#FIG. 1 is a structure block diagram of the present invention.

#The present invention is characterized in that a signal control circuit and a motor drive circuit are integrated into a motor control device, and the same input pin is used as an input contact of rotation direction and braking signals of a motor to reduce the number of pins of the signal control circuit and to miniaturize the product.

#As shown in FIG. 1, a motor control device 10 comprises a signal control circuit 12 having an input pin 14 for input of an electronic signal so that the signal control circuit can output different motor drive signals according to input electronic signals. Two switch circuits 16 and 16′ are connected to the signal control circuit 12. An inverter 18 is disposed between the two switch circuits 16 and 16′. The inverter 18 switches the motor drive signal among the two switch circuits 16 and 16′ and transmits it to a driver 20, which is connected to a motor drive circuit 28. The switch circuits 16 and 16′ are of break before make configuration, wherein the current connection of the two switch circuits 16 and 16′ is broken before the next time of connection of the two switch circuits 16 and 16′ to avoid short circuit between signals. A power source circuit 22 comprising a bias circuit 24 and a bandgap reference circuit 26 is connected to the motor drive circuit 28 to provide electricity for the motor drive circuit 28.

#The above signal control circuit 12 is a three-phase control circuit. A comparison voltage, generally being half the input voltage (e.g., 2.5V), is set in the signal control circuit 12. If the voltage of the electronic signal from the input pin 14 is larger than the comparison voltage, the motor drive signal is set to be a signal for driving the motor to make forward rotation. If the voltage of the electronic signal from the input pin 14 is smaller than the comparison voltage, the motor drive signal is set to be a signal for driving the motor to make reverse rotation. If the input electronic signal is a voltage pulse letting the voltage of the electronic signal be raised from a value smaller than the comparison voltage to a value larger than the comparison voltage, the motor drive signal is set to be a signal for braking the motor. The input pin 14 of the signal control circuit 12 is also electrically connected to an over voltage protection circuit 30 and an over current protection circuit 32 to provide protection for the signal control circuit 12.