Single phase motor driving device

A device for driving a single phase motor is provided. The device controls the rotation of the single phase motor according to at least a control signal. The single phase motor driving device includes a control apparatus and a detection apparatus. The control apparatus detects the rotation or stopped rotation of the single phase motor, and outputs a detection signal and at least the control signal. The detection apparatus coupled to the control apparatus generates a first comparison signal and a second comparison signal according to the detection signal, compares the first comparison signal with the second comparison signal to generate a comparison result, and then further outputs a rotation signal or a stopped rotation signal according the comparison result; wherein the control apparatus generates the at least the control signal according the rotation signal and the stopped rotation signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a driving device, in more particularly to a single phase motor driving device.

2. Description of the Related Art

A variety of heat dissipation apparatuses have been developed as the higher power consumption of the electronic components results in increased heat generation. A radiator fan, or a plurality of fans, controlled by a motor is the most common method of dissipating heat.

The specific operation of a single phase motor is set forth in the following description.FIG. 1is a schematic view of a conventional single phase motor. As shown inFIG. 1, in a conventional single phase motor driving device, NPN bipolar transistor2and4drive the current to a single phase coil6toward a direction12based on the provided driving signal A and D. Thus, the collector-emitter path of the bipolar transistor2, the single phase coil6, and collector-emitter path of the bipolar transistor4, are serially connected between a power supply VCCand a ground VSS. Similarly, NPN bipolar transistor8and10drives the current to the single phase coil6toward a direction14based on the provided driving signal C and B.

Consequently, the collector-emitter path of the bipolar transistor8, the single phase coil6, and the collector-emitter path of the bipolar transistor10are serially connected between the power supply VCCand the ground VSS. Thus, the bipolar transistor2and4, and the bipolar transistor8and10are complementarily turned on and off, thereby controlling the rotation of the motor by changing directions of the driving current passing the single phase coil6.

The single phase motor continues to rotate while the driving current is supplied by the power supply. When the single phase motor is obstructed or otherwise incapacitated, a gridlock/deadlock state occurs and the current flowing through the single phase motor from the power supply may overheat and burn out the single phase motor. The entire electronic system, including all components thereof, may be damaged from due to overheating. It is thus desirable to detect whether a single phase motor is in deadlock state, and effectively stop supplying driving current to prevent burnout of the single phase motor.

BRIEF SUMMARY OF THE INVENTION

The invention provides a single phase motor driving device for controlling the rotation of a single phase motor according to at least a control signal, wherein the single phase motor driving device comprises a control apparatus and a detection apparatus. The control apparatus detects the rotation or stopped rotation of the single phase motor to generate a detection signal and at least the control signal. The detection apparatus coupled to the control apparatus generates a first comparison signal and a second comparison signal according to the detection signal, compares the first comparison signal with the second comparison signal to generate a comparison result, and further outputs a rotation signal or a stopped rotation signal in accordance with the comparison result, wherein said control apparatus generates at least the control signal based on the rotation signal and the stopped rotation signal.

A detailed description is given in the following with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 2, which is a block diagram illustrating a single phase motor driving device according to the invention. As shown inFIG. 2, a single phase motor driving device20controls the rotation of a single phase motor26according to at least a control signal Sc, wherein the single phase driving device20comprises a control apparatus22and a detection apparatus24. The control apparatus22detects the rotation or stopped rotation of the single phase motor26, generates a detection signal SDand at least the control signal Sc. In some embodiments, the control apparatus22further comprises a Hall component (not shown inFIG. 2), wherein the Hall component (not shown inFIG. 2) detects the rotation or stopped rotation of the single phase motor. The detection signal SDis a discharge pulse. The detection apparatus24coupled to the control apparatus22generates a first comparison signal S1and a second comparison signal S2according to the detection signal SD, compares the first comparison signal S1with the second comparison signal S2to generate a comparison result, and subsequently outputs a rotation signal SRand a stopped rotation signal SPin accordance with the comparison result, wherein said control apparatus22generates at least the control signal SCaccording to the rotation signal SRor stopped rotation signal SP. In an embodiment, the single phase motor driving device20disclosed is embedded in integrated circuits.

Referring toFIG. 3, which is an exemplary view of a signal phase motor in a single phase motor driving device according to the invention. As shown inFIG. 3, the single phase motor26comprises a first transistor30and36, and a second transistor32and34, wherein the first transistor30and36provide a driving current with a first direction (Arrow44) for a single phase coil38, as well as the second transistor32and34provide a driving current with a second direction (Arrow46) for the single phase coil38. At least the control signal SC, respectively controls the first transistor30and36, and the second transistor32and34, to generate the driving current with the first direction (Arrow44) and the driving current with the second direction (Arrow46).

In the present embodiment, the first transistor30and36, and the second transistor32and34are the bipolar transistors. However, it is not limited to such transistors, the first transistor30and36, and the second transistor32and34of the invention may be N-channel MOSFETs or P-channel MOSFETs.

In addition, as shown inFIG. 3, the single phase motor driving device20having a regenerating diode40and42for regenerating the driving current of the single phase coil38may substantially regenerate the driving current of the single phase coil38. For the first transistor30and36, and the second transistor40and42, though the regenerating diode40and42in the present embodiment are the additional components, but not limited to this, the parasitic diodes of the first transistor30and36, and the second transistor32and34, may be utilized to reduce the size of the single phase motor driving device20.

Referring toFIG. 4, which is an exemplary view of a detection apparatus in a single phase motor driving device according to the invention. As shown inFIG. 4, the detection apparatus24comprises a voltage source VDD, an inverter242, a first transistor244, a second transistor242, a capacitor248and a comparator250. The inverter242having an input terminal and an output terminal, wherein the input terminal coupled to the control apparatus22receives the detection signal SDto generate an opposite signal S1. The first transistor244having three terminals, a first terminal (source), a second terminal (gate), and a third terminal (drain), wherein the first terminal (source) is coupled to the voltage source VDD, and the second terminal (gate) is coupled to the output terminal of the inverter242for receiving the opposite signal S1on the second terminal.

The second transistor246having three terminals, a first terminal (gate), a second terminal (drain) and a third terminal (source), wherein the first terminal (gate) is coupled to the control apparatus22for receiving a detection signal SD, and the third terminal (source) is coupled to a ground VSS. The capacitor248has a first terminal QBand a second terminal Q, wherein the first terminal QBis coupled to the second terminal (drain) of the second transistor246, and then the capacitor248generates a first comparison signal S1according to a first current I1from the first terminal of the capacitor248and a second comparison signal S2according to a second current I2from the second terminal of the capacitor248. In an embodiment, the first comparison signal S1may be a charging voltage, and the second comparison signal S2may be a discharge voltage.

The comparator250includes a positive input terminal and a negative input terminal, wherein the positive input terminal is coupled to the first terminal QBof the capacitor248, as well as the negative input terminal is coupled to the second terminal Q of the capacitor248, for comparing the first comparison signal S1with the second comparison signal S2, generating a comparison result, and subsequently outputting a rotation signal SRand a stopped rotation signal SPin response to the comparison result. As shown inFIG. 4, a logic level high from the output terminal of the comparator250indicates output of the rotation signal SR, and a logic level low from the output terminal of the comparator250indicates output of the stopped rotation signal SP.

Additionally, the detection apparatus24further comprises a first current source252and a second current source254. The first current source252coupled to the first terminal QBof the capacitor248provides the first current I1. The second current source254coupled to the second terminal Q provides the second current I2.

Referring toFIG. 2andFIG. 3, the operation of the control apparatus22and the detection apparatus24is provided in the following description. The detection apparatus24detects the rotation or stopped rotation of the single phase motor26, and subsequently generates the rotation signal SRor stopped rotation signal SP. When the single phase motor26is unable to rotate, the regeneration of the driving current for the single phase coil38by the control apparatus22may temporarily be suspended until the output of the detection apparatus24is switched from the stopped rotation single SPto the rotation signal SR. Additionally, when the single phase motor26stops, the phase relationship between a magnet adjacent to a rotor (not shown) and the Hall component (not shown) is fixed during a period, and thereby the single phase motor26is incapable of rotating for the regenerating operation of driving current from the control apparatus22. By the single phase motor driving device20, the control apparatus22stops regenerating the driving current until the single phase motor26rotates. As a result, the single phase motor26is capable of returning to a start substantially even if the single phase motor26is stopped in the position and unable to start.

Referring toFIGS. 2˜5,FIG. 5is a waveform diagram showing the timing of a single phase motor driving device according to the invention. As shown inFIGS. 2˜5, the control apparatus22generates the sinusoidal wave signals with 180 degree phase difference represented in a solid line and a dashed line according to the rotating position of the single phase motor26. The sinusoidal wave signal converts the square wave signal through the squaring process. The control apparatus22then generates the detection signal SDaccording to the changing point of the square wave signal (i.e. current switching point of the driving current from the single phase coil38of the single phase motor26). The detection signal SDis provided to the detection apparatus24. When the single phase motor26rotates, the comparator250outputs a rotation signal SRwhen the charging voltage of the capacitor248is less than the discharge voltage. When the single phase motor26stops, the comparator250outputs a stopped rotation signal SPdue to the charging voltage of the capacitor248being greater than the discharge voltage. The control apparatus22calculates and generates at least a control signal SCaccording to the rotation signal SRand the stopped rotation signal SPfrom the detection apparatus24. Additionally, the single phase coil38controls the driving current, thus driving of the single phase motor26is accomplished.

The invention relates a single phase motor driving device, wherein the single phase motor driving device has a control apparatus and a detection apparatus. The detection apparatus detects rotating state of a single phase motor, and generates a rotation signal SRor a stopped rotation signal SP. The control apparatus outputs at least a control signal SCaccording to the rotation signal SRor stopped rotation signal SPto stop providing the control signal Sc for the single phase motor, i.e. stop providing the driving current for the single phase motor. Accordingly, it is possible to prevent the single phase motor from overheating and burnout due to the constantly provided driving current when the single phase motor is in a gridlock/deadlock state due to a malfunction.