WO2008032727A1

WO2008032727A1 - Single-phase brushless motor drive device

Info

Publication number: WO2008032727A1
Application number: PCT/JP2007/067707
Authority: WO
Inventors: Hidetoshi Ueda
Original assignee: Panasonic Electric Works Co., Ltd.
Priority date: 2006-09-13
Filing date: 2007-09-12
Publication date: 2008-03-20
Also published as: TWI336990B; TW200828774A; JPWO2008032727A1; JP4915965B2

Abstract

A single-phase brushless motor drive device includes: a bridge circuit having a first to a fourth switching element; a detection circuit; and a control circuit. The first switching element has a control terminal connected to one end of a motor coil. When the fourth switching element turns ON or OFF, the first switching element turns ON or OFF via one of the potentials of the motor drive power source. The second switching element has a control terminal connected to the other end of the motor coil. When the third switching element turns ON or OFF, the second switching element turns ON or OFF via one of the potentials of the power source. The control circuit alternately applies voltage of the control power source to the control terminals of the third and the fourth switching element so as to alternately turn ON and OFF the third and the fourth switching element according to the ON/OFF control signal from the detection circuit.

Description

Specification

Single-phase brushless motor drive

Technical field

[0001] The present invention relates generally to single-phase brushless motor drives. More specifically, the present invention relates to a magnetic core coil composed of a rotatable magnet 'rotor having a plurality of magnetic poles, a motor' coil, and a stator 'core disposed so as to face a side peripheral portion of the rotor. Related to a drive used in a single-phase brushless motor comprising:

Background art

[0002] Japanese Patent Application Publication No. 2004-135374, issued April 30, 2004, discloses a single-phase brushless motor drive. This device includes a full bridge circuit (drive circuit) composed of first to fourth switching elements, a detection circuit composed of a detection element and a comparator, a control circuit composed of a distribution circuit and a delay circuit, Can be divided into The first switching element is connected between the positive terminal of the DC power supply and the first end of a motor coil (winding) provided in the motor. The second switching element is connected between the positive terminal and the second end of the motor coil. The third switching element is connected between the first end and the negative terminal of the DC power supply. The fourth switching element is connected between the second end and the negative terminal. The detection element detects the position of the magnetic pole of the rotor provided in the motor. The comparator converts the output signal from the detection element into a rectangular wave signal and supplies it to the distribution circuit and the delay circuit. Further, the position of the detection element is changed so that the timing of the output signal of the delay circuit is substantially equal to that of the rectangular wave signal obtained from the corresponding comparator in the conventional single-phase brushless motor driving device. The delay circuit delays the rectangular wave signal from the comparator and supplies it to the distribution circuit. The distribution circuit turns on and off the first to fourth switching elements based on the rectangular wave signal from the comparator and the output signal of the delay circuit.

That is, the distribution circuit turns off the second switching element in accordance with the rising edge of the rectangular wave signal from the comparator. Thereafter, according to the rising edge of the output signal of the delay circuit, the distribution circuit turns on the first and fourth switching elements and turns on the third switching element. H Subsequently, the distribution circuit turns off the first switching element in response to the falling edge of the rectangular wave signal from the comparator. Thereafter, in response to the falling edge of the output signal of the delay circuit, the distribution circuit turns on the second and third switching elements, and the fourth switching element.

[0004] In this device, the combination of the first and fourth switching elements and the combination of the second and third switching elements are not alternately turned on and off at the same time, so that it is possible to prevent the occurrence of back electromotive force. .

By the way, when a single-phase brushless “motor” is driven by a full bridge circuit, the first to fourth switching elements of the full bridge circuit must be turned on and off through a control circuit. Such a control circuit generally includes a dedicated IC or a microcomputer. Since the dedicated IC is more expensive than the general-purpose IC, and the microcomputer is also expensive, the control circuit, and hence the drive device having the control circuit, is expensive. If a general-purpose IC is used as a drive device, the device can be made cheaper, but the design flexibility and output performance of a product incorporating the device are limited. Moreover, since it is necessary to connect all control terminals of the first to fourth switching elements to the dedicated or general-purpose IC, wiring of the conductor pattern on the printed circuit board is generally complicated. It is also desirable to connect fewer wires (eg conductor patterns) between the full bridge circuit and the control circuit to avoid noise.

Disclosure of the invention

[0006] An object of the present invention is to reduce the cost of the control circuit, eliminate the limitation on the design flexibility and output performance of the product equipped with the drive device of the present invention, and eliminate the restriction between the full bridge circuit and the control circuit. For example, the wiring is simplified to avoid noise.

[0007] The present invention provides a drive device for a single-phase brushless motor. The motor includes a rotatable magnet 'rotor and a magnetic core coil. The rotor has a plurality of magnetic poles. The magnetic core is composed of a stator core disposed so as to face the side periphery of the rotor, and a motor coil having first and second ends. The drive device of the present invention includes a full bridge circuit, a detection circuit, and a control circuit. The full bridge circuit consists of the first to fourth switching elements. The first switching element is between the positive terminal of the motor drive power supply and the first end. Connected between. The second switching element is connected between the positive terminal and the second end. The third switching element is connected between the first end and the negative terminal of the motor drive power source. The fourth switching element is connected between the second end and the negative terminal. The detection circuit has a field sensor that generates a detection signal corresponding to the position of the magnetic pole of the rotor, and generates an on / off control signal from the detection signal. The control circuit turns on and off the first to fourth switching elements using the voltage of the control power supply based on the on / off control signal. In a feature of the present invention, the control terminal of the first switching element is connected to the second end, and the first switching element passes through any potential of the motor drive power source when the fourth switching element is turned on or off, respectively. Turn on or off. The control terminal of the second switching element is connected to the first terminal, and the second switching element is turned on or off through any potential of the motor drive power supply when the third switching element is turned on or off. The control circuit alternately applies the voltage of the control power supply to the control terminals of the third and fourth switching elements so as to alternately turn on and off the third and fourth switching elements in accordance with the on / off control signal.

[0008] According to the present invention, the control circuit is made inexpensive, the flexibility of the design of the product equipped with the drive device of the present invention and the limitation on the output performance are eliminated, and the wiring between the full bridge circuit and the control circuit is eliminated. For example, noise can be avoided.

[0009] In one enhancement embodiment, the drive device further comprises a monitoring circuit and a stop circuit.

The monitoring circuit is configured to detect abnormal conditions where the full 'bridge circuit begins to short circuit. The stop circuit is configured to turn off the third and fourth switching elements when the monitoring circuit detects the abnormal state. In this configuration, the full bridge circuit stops driving the single-phase brushless motor, so that a short-circuit current can be prevented from flowing into the full bridge circuit.

[0010] In one embodiment, the monitoring circuit is configured to monitor the voltage of the control power source and detect the abnormal state when the voltage of the control power source falls below the reference voltage.

[0011] In one embodiment, the monitoring circuit monitors a current flowing through the third or fourth switching element, and detects the abnormal state when the current flowing through the third or fourth switching element exceeds a reference current. Configured as follows. Brief Description of Drawings

[0012] Preferred embodiments of the invention are described in further detail. Other features and advantages of the present invention will be better understood with reference to the following detailed description and accompanying drawings.

FIG. 1 is a circuit diagram of a drive device for a single-phase brushless motor according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a monitoring circuit and a stop circuit in the embodiment.

FIG. 3 illustrates an operation waveform of the embodiment.

FIG. 4 is a circuit diagram of a monitoring circuit and a stop circuit in a modified embodiment.

FIG. 5 illustrates an operation waveform of the modified embodiment.

FIG. 6 illustrates an example of the monitoring circuit of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

[0013] FIG. 1 illustrates a single-phase brushless motor drive, according to one embodiment of the present invention. The driving device 10 is composed of a full bridge circuit 11, a detection circuit 12, a control circuit 13, a monitoring circuit 14 and a stop circuit 15, and is used for a specific brushless motor. This particular brushless 'motor is a single phase brushless' motor 19, which includes a rotatable magnet rotor 191 and a magnetic core coil 192. The rotor 191 has a plurality of magnetic poles (not shown), and is mounted on a rotatable motor shaft 190, for example. The magnetic core coil 192 is composed of a stator core 193 disposed so as to face the side periphery (cylindrical surface) of the rotor 191 and a motor coil 194 having first and second ends 195 and 196 ( For example, see Japanese Patent Application Publication Nos. 2006-333585 and 2001-224156). For example, the rotor 191 is formed of a cylindrical cage in which the magnetic core coil 192 is placed, and the coil 192 is disposed so as to face the inner surface of the side peripheral portion of the rotor 191.

The full bridge circuit 11 has first to fourth switching elements 111 to 114 and is connected between the positive and negative terminals of a DC power source (motor drive power source) 1. That is, the first switching element 111 is connected between the positive terminal of the power source 1 and the first end 195. The second switching element 112 is connected between the positive terminal and the second end 196. Third switching element 113 is connected between first end 195 and the negative terminal of power supply 1. The fourth switching element 114 has a second end 196 and Connected between the negative terminal.

In the example of FIG. 1, the element 111 is a P-channel FET, and its source and drain terminals are connected to the positive terminal and the first end 195, respectively. The element 112 is a P-channel FET, and its source and drain terminals are connected to the positive terminal and the second end 196, respectively. The element 113 is an N-channel FET, and its drain and source terminals are connected to the first end 195 and the negative terminal, respectively. The element 114 is an N-channel FET, and its drain and source terminals are connected to the second end 196 and the negative terminal, respectively. Not limited to these, each of the first to fourth switching elements of the present invention may be, for example, a combination of a bipolar transistor (NPN type or PNP type transistor) having a corresponding function and a diode.

In accordance with a feature of the present invention, the control terminal (gate) of the first switching element 111 is connected to the second end 1 96 and the control terminal (gate) of the second switching element 112 is connected to the first end 195. It is done. However, the present invention is not limited to this, and the control terminals of the first and second switching elements of the present invention may be connected to the second and first ends via resistors or diodes, respectively. In addition, in the configuration of FIG. 1, the circuit 11 further includes resistors 115 and 116, and the control terminals of the elements 111 and 112 are connected to the positive terminal of the power source 1 through the resistors 115 and 116, respectively. . Therefore, element 111 is turned on or off through any potential of power supply 1 when element 114 is turned on or off, respectively. Similarly, element 112 is turned on or off through any potential of power supply 1 when element 113 is turned on or off, respectively.

The detection circuit 12 includes a field sensor 120 that generates a detection signal corresponding to the position of the magnetic pole of the rotor 191, and generates the detection signal force on / off control signal to control the control signal Supply to circuit 13. For example, the circuit 12 is a Hall IC including a Hall element as the field 'sensor 120 and is disposed in the vicinity of the rotor 191. The Hall IC further includes, for example, an amplifier, a Schmitt circuit (Schmitt's trigger), and one or more output transistors. The on / off control signal is, for example, a rectangular wave signal. In an alternative embodiment, the detection circuit 12 is a discrete circuit comprising a Hall element, an amplifier, a Schmitt circuit, and one or more output transistors.

The control circuit 13 is controlled by a control power supply (based on an on / off control signal from the detection circuit 12. (DC power supply) The first to fourth switching elements 111 to 114 are turned on and off using the voltage Vcc of 2. In accordance with a feature of the present invention, the circuit 13 alternately turns on the elements 113 and 114 by alternately applying the voltage Vcc to the control terminals of the third and fourth switching elements 113 and 114 according to the on / off control signal. And configured to turn off.

For example, in response to the rising edge of the on / off control signal, the circuit 13 connects the control terminal of the element 114 to the ground so as to turn off the element 114. After the first delay time from the rising edge, the circuit 13 applies the voltage Vcc to the control terminal of the element 113 so that the element 113 is turned on. Thereafter, in response to the falling edge of the on / off control signal, the circuit 13 connects the control terminal of the element 113 to the ground so as to turn off the element 113. After the second delay time from the falling edge, the circuit 13 applies the voltage Vcc to the control terminal of the element 114 so that the element 114 is turned on. Thereafter, the circuit 13 repeats the same switching operation.

In this case, the element 111 is turned on or off in response to the turning on or off of the element 114, and the element 112 is turned on or off in response to the turning on or off of the element 113, respectively. That is, when the element 114 is turned off, the positive potential (voltage Vs) of the power supply 1 is applied to the control terminal of the element 111 via the resistor 115, so that the element 111 is also turned off. At this time, the circuit 11 stops applying the voltage Vs to the motor coil 194. When the element 113 is turned on, the negative potential (ground potential) of the power supply 1 is applied to the control terminal of the element 112, so that the element 112 is also turned on. At this time, if it is determined that the polarity on the second end (196) side of the voltage Vs applied to the coil 194 is positive, the power supply 1 applies + Vs to the coil 194. When the element 113 is turned off, since a positive potential is applied to the control terminal of the element 112 via the resistor 116, the element 112 is also turned off. At this time, the circuit 11 stops applying the voltage Vs to the coil 194. When element 114 is turned on, a negative potential is applied to the control terminal of element 111, so element 111 is also turned on. At this time, the power source 1 applies —Vs to the coil 194.

As shown in FIG. 1, the control circuit 13 for alternately turning on and off the elements 113 and 114 can be constituted by resistors 130 and 131, switching elements 132 and 133, and a NOT circuit 134. . Resistor 130 is connected in series with element 132, and the series set of resistor 130 and element 132 is connected in parallel with power supply 2. The junction point of the resistor 130 and the element 132 is connected to the control terminal of the element 114. Element 132 is a bipolar 'transistor (For example, NPN transistor) or FET, and the control terminal of the element 132 is connected to the output terminal of the detection circuit 12. Similarly, the resistor 131 is connected in series with the element 133, and the series set of the resistor 131 and the element 133 is connected in parallel with the power supply 2. The junction point of the resistor 131 and the element 133 is connected to the control terminal of the element 113. The element 133 is a bipolar transistor (for example, an NPN transistor) or an FET, and the control terminal of the element 133 is connected to the output terminal of the circuit 12 via the NOT circuit 134.

In the present embodiment, the circuit 13 further includes two delay circuits. That is, the capacitor 135 is connected in parallel with the element 132, and the resistor 130 and the capacitor 135 constitute a first delay circuit that determines the first delay time. Further, the capacitor 136 is connected in parallel with the element 133, and the resistor 131 and the capacitor 136 constitute a second delay circuit that determines the second delay time. The second delay time is set to be substantially equal to the first delay time. Therefore, the elements 132 and 133 are turned on in response to the rising and falling edges of the on / off control signal to turn off the elements 114 and 113, respectively. Elements 133 and 132 are turned off and elements 113 and 114 are turned on after the first and second delay times from the rising and falling edges, respectively.

[0023] The monitoring circuit 14 is configured to detect an abnormal condition in which the full bridge circuit 11 begins to short circuit. For example, as shown in FIG. 2, the circuit 14 can be constituted by a Zener diode 140, resistors 141 and 142, and an amplifier circuit 143. The circuit 143 can be formed of, for example, a transistor. The diode 140 and the resistors 141 and 142 are connected in series with each other, and the series set is connected in parallel with the power supply 2. The input terminal of circuit 1 43 is connected to the junction point of resistors 141 and 142, and circuit 143 monitors the voltage Vcc of power supply 2 through diode 140 and resistors 141 and 142. When voltage Vcc falls below a reference voltage (Vref) determined by diode 140, circuit 143 detects an abnormal condition and provides a LOW signal to stop circuit 15. That is, when the voltage Vcc falls below the reference voltage, the diode 140 is turned off and the ground potential is applied to the input terminal of the circuit 143, so that the circuit 143 supplies the LOW signal to the circuit 15. When the voltage Vcc is equal to or exceeds the reference voltage (ie, the power supply 2 is normal), the diode 140 is turned on, so that the voltage obtained by dividing the voltage Vcc by the diode 140 and the resistors 141 and 142 is Input terminal Applied to the child. As a result, the circuit 143 supplies a HIGH signal to the circuit 15.

[0024] The reference voltage is set to a voltage equal to or higher than the voltage Vcc immediately before the element 111 or 112 is turned off when the voltage Vcc decreases. Further, the reference voltage can be limited to a voltage equal to or lower than a voltage at which the on-resistance of the element 113 or 114 starts to increase. Desirably, the reference voltage is set to a voltage equal to or lower than the voltage at which the on-resistance of the element 113 or 114 starts to increase!

The stop circuit 15 is configured to turn off the third and fourth switching elements 113 and 114 when the monitoring circuit 14 detects an abnormal state. For example, the circuit 15 can be constituted by switch elements 150 and 151 and a NOT circuit 152. The circuit 152 can be composed of, for example, a transistor. The element 150 is an NPN transistor, for example, and is connected between the control terminal of the element 113 and the ground. The element 151 is an NPN transistor, for example, and is connected between the control terminal of the element 114 and the ground. The input terminal of the circuit 152 is connected to the output terminal of the amplifier circuit 143, and the output terminal of the circuit 152 is connected to the control terminals (bases) of the elements 150 and 151.

When the circuit 14 detects an abnormal state and supplies a LOW signal to the circuit 15, the circuit 152 applies a HIGH signal to the control terminals of the elements 150 and 151. As a result, since the elements 150 and 151 are turned on and the elements 113 and 114 are turned off, the full bridge circuit 11 stops driving the motor 19. In short, it is possible to stop driving the motor 19 while the circuit 14 detects the abnormal state. When power supply 2 is normal, circuit 14 provides a HIGH signal to circuit 15 so that circuit 152 provides a LOW signal to the control terminals of elements 150 and 151. As a result, circuit 11 is allowed to drive motor 19 because elements 150 and 151 are turned off and elements 113 and 114 are allowed to turn on and off.

Next, the operation of the present embodiment will be described with reference to FIG. After the power supplies 1 and 2 are activated, the circuit 13 alternately applies the voltage Vcc of the power supply 2 to the control terminals of the elements 113 and 114 in accordance with the on / off control signal from the circuit 12 to thereby generate the elements 113 and 114. Alternately turn on and off. For example, at the time tl, the circuit 13 turns on the element 132 so as to turn off the element 114 by connecting the control terminal of the element 114 to the ground in response to the rising edge of the on / off control signal. At this time, the elements 111 and 114 are turned off, and the elements 112 and 113 are turned off. As such, circuit 11 stops applying voltage Vs from power supply 1 to motor coil 194. After the first delay time from the rising edge (t2), the circuit 13 turns off the element 133 so as to turn on the element 113 by applying the voltage Vcc to the control terminal of the element 113. At this time, the elements 112 and 113 force S are turned on, and each of the elements 111 and 114 is in the OFF state, so that the circuit 11 marks + V s in the coinlet 194.

[0028] At time t3, the circuit 13 turns on the element 133 so as to turn off the element 113 by connecting the control terminal of the element 113 to the ground in response to the falling edge of the on / off control signal. At this time, since the elements 112 and 113 are turned off and each of the elements 111 and 114 is in the off state, the circuit 11 stops applying + Vs to the coil 194. After the second delay time from the falling edge ( _t4 ), the circuit 13 turns off the element 132 so that the element 114 is turned on. At this time, since the elements 111 and 114 are turned on and each of the elements 112 and 113 is in the off state, the circuit 11 applies Vs to the coil 194.

[0029] As the circuit 13 repeats such control, a rectangular wave alternating (AC) voltage is applied to the coil 194, and a rectangular wave alternating (AC) current is supplied to the coil 194. As a result, the magnetic needle coil 192 The rotor 191 is rotated by generating an alternating magnetic field.

[0030] In such operation, a short-circuit current may flow through the circuit 11 if the voltage Vcc falls below the reference voltage Vref due to several causes (eg, voltage drop or power down). For example, in the period corresponding to t2-13, when the voltage Vcc falls below the voltage Vref, the gate voltage of the element 113 decreases and the on-resistance of the element 113 increases. In this case, since the voltage obtained by multiplying the on-resistance by the current flowing through the inductor 194 becomes the drain-source voltage of the element 113, the gate voltage of the element 112 rises from the ground potential to the drain-source voltage. As a result, the element 112 may be turned off. When element 112 is turned off, a back electromotive force is induced in coil 194. Since the polarity of the back electromotive force on the first end (195) side is positive, the body diode of the element 114 is turned on and the drain terminal of the element 114 becomes the ground potential. As a result, a voltage lower than the ground potential is applied to the gate of the element 111 and the element 111 is turned on, so that a short-circuit current flows through the elements 111 and 113 in the circuit 11.

However, in the present embodiment, when the voltage Vcc falls below the voltage Vref, the circuit 14 supplies the LO W signal to the circuit 15, and the circuit 15 turns off the elements 113 and 114. Therefore, times Since the path 11 stops driving the motor 19, the force S prevents the short-circuit current from flowing into the circuit 11.

[0032] In addition, the control circuit 13 is made inexpensive, the flexibility of the design of the product equipped with the drive device 10 and the restriction on the output performance are eliminated, and the wiring between the full bridge circuit 11 and the control circuit 13 is eliminated. For example, noise can be avoided.

[0033] In an alternative embodiment, the monitoring circuit 14 includes a microcomputer and an A / D converter. The microcomputer monitors the voltage Vcc through the A / D converter and supplies a LOW signal to the stop circuit 15 when the digital value of the voltage Vcc is smaller than the reference voltage value.

In an alternative embodiment, the amplifier circuit 143 is composed of an operational amplifier or the like, and the NOT circuit 152 is also composed of an operational amplifier or the like. These operational amplifiers operate with power from a second control power supply (not shown! /), Which is a DC power supply.

[0035] In one variation, the monitoring circuit 14 is disposed between the junction of the source terminals of the elements 113 and 114 and the ground. In addition, the NOT circuit 152 of the stop circuit 15 is deleted. The circuit 14 is configured to monitor the current flowing through the element 113 or 114 and detect the abnormal condition when the current flowing through the element 113 or 114 exceeds a reference current (Iref). The reference current is set to the current up to the maximum rating of each switching element in circuit 11. Preferably, the reference current is set to the lowest current to ensure the current flowing through the motor coil 194 during normal operation.

For example, as shown in FIG. 4, the circuit 14 of this modified embodiment can be configured by resistors 145 to 147 and an operational amplifier (op amp) 148. In this case, the amplifier 148 operates with power from the second control power supply (DC power supply) 3. The resistor 145 is, for example, a shunt resistor, and is connected between the junction point A of the source terminals of the elements 113 and 114 and the ground. The resistor 145 detects a current (detection current) flowing through the element 113 or 114, and generates a voltage corresponding to the detection current. Resistor 146 is connected in series with resistor 147, and the series set of resistors 146 and 147 is connected in parallel with power supply 3. Resistors 146 and 147 generate a voltage corresponding to the reference current from the voltage of the power source 3. The non-inverting input terminal of the amplifier 148 is connected to the junction A, and the inverting input terminal of the amplifier 148 is connected to the junction point of the resistors 146 and 147. The output terminal of the amplifier 148 is connected to the elements 150 and 1 of the stop circuit 15. Connected to 51 control terminals. Thereby, the operational amplifier 148 operates as a comparator.

The operational amplifier (comparator) 148 compares the detected current with the reference current by comparing the voltage corresponding to the detected current with the voltage corresponding to the reference current. As shown in FIG. 5, when the detected current is equal to or greater than the reference current Iref, the amplifier 148 supplies a HIGH signal to each control terminal of the elements 150 and 151. As a result, since the elements 150 and 151 are turned on and the elements 113 and 114 are turned off, the full bridge circuit 11 stops driving the motor 19. When the detected current is smaller than the reference current Iref, the amplifier 148 supplies a LOW signal to each control terminal of the elements 150 and 151. As a result, circuit 11 is allowed to drive motor 19 since elements 150 and 151 are turned off and elements 113 and 114 are allowed to turn on and off.

In the example of the monitoring circuit 14 in FIG. 4, the circuit 14 further includes a holding circuit. The holding circuit is configured to hold the HIGH signal supplied by amplifier 148 until the holding circuit is reset or a certain time has elapsed. For example, as shown in FIG. 6, the holding circuit 149 can be composed of a diode 1490, a capacitor 1491, and resistors 1492 and 1493. In this case, when the output level of the amplifier 148 is the HIGH level, a voltage corresponding to the level is applied to the non-inverting input terminal of the amplifier 148 via the capacitor 1491 and the resistor 1492. Therefore, amplifier 148 can continue to supply a HIGH signal to each of the controller P terminals of elements 150 and 151 for a hold time that is adjusted according to the capacitance of capacitor 1491.

[0039] Power describing the present invention in terms of several preferred embodiments Various modifications and variations can be made by those skilled in the art without departing from the true spirit and scope of the invention.

Claims

The scope of the claims

[1] Single-phase brushless' motor drive device, wherein the motor includes a rotatable magnet having a plurality of magnetic poles, a stator core disposed so as to face a side peripheral portion of the rotor, and a first core And a magnetic core coil composed of a motor coil having a first end and a second end,

The device

A first switching element connected between the positive terminal of the motor drive power source and the first end; a second switching element connected between the positive terminal and the second end; the first end and the motor A full bridge circuit composed of a third switching element connected between the negative terminal of the drive power supply and a fourth switching element connected between the second end and the negative terminal;

A detection circuit for generating a detection signal corresponding to the position of the magnetic pole of the rotor and generating an on / off control signal from the detection signal;

A control circuit for turning on and off the first to fourth switching elements using the voltage of the control power supply based on the on / off control signal;

With

The control terminal of the first switching element is connected to the second end, and when the fourth switching element is turned on or off, the first switching element is turned on or off through any potential of the motor driving power source. And

The control terminal of the second switching element is connected to the first end, and when the third switching element is turned on or off, the second switching element is turned on or off through any potential of the motor driving power source. And

The control circuit alternately switches the voltage of the control power supply to the control terminals of the third and fourth switching elements so as to alternately turn on and off the third and fourth switching elements according to the on / off control signal. Apply to

Single-phase brushless motor drive.

[2] a monitoring circuit for detecting an abnormal state in which the full-bridge circuit starts to short-circuit, and when the monitoring circuit detects the abnormal state, the third and fourth switching elements are turned off. With stop circuit to

The single-phase brushless motor drive device according to claim 1, further comprising:

3. The single-phase brushless motor driving apparatus according to claim 2, wherein the monitoring circuit monitors the voltage of the control power supply and detects the abnormal state when the voltage of the control power supply falls below a reference voltage.

[4] The monitoring circuit monitors a current flowing through the third or fourth switching element, and detects the abnormal state when a current flowing through the third or fourth switching element exceeds a reference current. 2. Single-phase brushless motor drive device according to 2.