JP2596390B2 - H-bridge type motor drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an H-bridge type motor drive circuit, and more particularly to an H-bridge type motor drive circuit formed by MOS transistors and capable of controlling the rotation of a DC motor in both forward and reverse directions.

[0002]

2. Description of the Related Art As a DC motor drive circuit for controlling the rotation of a DC motor in both forward and reverse directions, an H-type bridge circuit is formed by four transistors and a DC motor, and these four transistors are turned on and off. H controls the rotation direction, rotation, and stop of the DC motor by controlling
Bridge type motor drive circuits are commonly used.
FIG. 5 shows a typical circuit of such an H-bridge type motor drive circuit.

In this H-bridge type motor drive circuit, the drain is connected to the (+) side electrode of the DC power supply E1, the source and the substrate are connected, and the gate is turned on and off by control signals GC1x and GC2x applied to the gate. First
The second MOS transistors T1, T2 and the drain are
A third MOS transistor which is connected to the source of the S transistor T1, connects the source and the substrate to the ground potential point to which the (-) side electrode of the DC power supply E1 is connected, and turns on and off by the control signal GC3x given to the gate. T3 and a fourth MOS transistor T4 having a drain connected to the source of the MOS transistor T2, a source and a substrate connected to the ground potential point, and turned on and off by a control signal GC4x applied to the gate. And an H-bridge type output stage circuit 1 for driving and controlling the motor M1 between the connection point of the MOS transistors T2 and T4 and the level of the control signals GC1x to GC4x according to the rotation control signals F and R. And a control circuit 2x for controlling the rotation direction and rotation / stop of the motor M1. . D1 to D4 are parasitic diodes that are parasitic at the junction of the source, substrate and drain of the MOS transistors T1 to T4.

Next, the operation of this circuit will be described with reference to the current and voltage waveform diagrams of each part shown in FIG.

First, in order to rotate the motor M1 in the forward direction, the control signals GC1x and GC4x are set to a high level to
The S transistors T1 and T4 are turned on, and a current flows through a route indicated by a solid line a (current supply period Ta). To rotate the motor M1 in the reverse direction, the control signals GC2 and GC
3 is set to a high level, the MOS transistors T2 and T3 are turned on, and a current in a direction opposite to the solid line a flows to the motor M1 (not shown). 5 and 6 show an example in which the motor M1 is rotated in the forward direction. The same applies to the following description.

Next, in order to stop the rotation of the motor M1, the control signals GC1x and GC4x are set to low level, the MOS transistors T1 and T4 are turned off, and the supply of the current from the DC power supply E1 to the motor M1 is stopped. At this time,
A current due to the energy stored in the inductance component of the excitation winding and the like of the motor M1 flows through the parasitic diodes D3 and D2 as shown by a broken line b, and is regenerated to the DC power supply E1 (stored energy release period Tb).

The motor M1 normally rotates by inertia (inertia) even after the energy release period Tb has elapsed, and generates electric power by the rotational energy. The current at this time flows through the route of the dashed line c via the parasitic diodes D4 and D1, and is regenerated to the DC power supply E1 (power generation energy release period).

As a method of controlling the conduction / non-conduction of the MOS transistors T1 to T4, the above example (first example)
In addition, after the supply of the current from the DC power supply E1 to the motor M1 is stopped by turning off the MOS transistor T1, the control signal GC4x is maintained at a high level for a predetermined period so that M
There is also an example in which the OS transistor T4 is kept conductive to release the energy of the motor M1 (a second example, see, for example, Japanese Patent Application Laid-Open No. 2-142377).

The H-bridge type motor drive circuit is often configured as a one-chip IC including an H-bridge type output stage circuit 1 and a control circuit 2x, and many CMOS type ICs are included in the control circuit 2x. Includes logic circuits.

[0010]

In the first example, the conventional H-bridge type motor drive circuit described above uses two MOS transistors (for example, two MOS transistors for supplying current to the motor M1 when the rotation of the motor M1 is stopped). T1 and T4) are simultaneously turned off and the stored energy and the generated energy of the motor M1 are released through the parasitic diodes D1 to D4 of the MOS transistors T1 to T4.
The terminal of the motor M1, that is, the MOS transistor T
1 and T3 (node N1), MOS transistor T
The potential at the connection point (node N2) between T2 and T4 is equal to the supply voltage V of the direct current source E1 by the forward voltage of the parasitic diodes D1 and D2.
dd (refer to N1 and N2 in FIG. 6), and latch-up for turning on a thyristor parasitic on a CMOS logic circuit or the like such as the control circuit 2x formed on the same chip as the MOS transistors T1 to T4. There is a danger that a phenomenon may occur. Also, before the energy release of the motor M1 is completed, the MOS transistor T
When two of the transistors T1 to T4 are turned on, for example, when a current for discharging energy flows through the parasitic diodes D3 and D (D4 and D1), the MOS transistors T1 and T4 are turned off.
When T4 (T2, T3) is made conductive, the parasitic diode D
3, a reverse voltage is applied to D2 (D4, D1), and a reverse current flows during a period until the charges accumulated in the parasitic diodes D3, D2 (D4, D1) are released (reverse recovery). Phenomenon), MOS transistors T1-T3
In the second example, there is a problem that a through current flows between T2 and T4 to delay the driving of the motor M1, and in the second example, even after the current supply to the motor M1 is stopped, one MOS transistor (for example, T4) Can be prevented, the above-described latch-up phenomenon can be prevented. However, since the MOS transistor of the energy release route of the reactance component of the motor M1 is in the conductive state, the resistance of the route is reduced. Since the value becomes small, the time constant becomes large and there is a problem that the energy release period, that is, the time until the motor M1 stops, becomes long.

An object of the present invention is to provide an H-bridge type motor drive circuit capable of preventing a latch-up phenomenon of a control circuit and the like formed on the same chip and shortening the time required for stopping and driving the motor. Is to do.

[0012]

An H-bridge type motor drive circuit according to the present invention has one of a source and a drain connected to a first power supply terminal of a DC power supply, and a voltage of the DC power supply is applied in a reverse direction. A first and a second MOS transistor whose conduction and non-conduction are controlled by a control signal given to a gate having a parasitic diode between the source and the drain, and one of a source and a drain connected to the first and the second MOS transistors. And a parasitic diode to which the other of the source and the drain of the MOS transistor is connected to the second power supply terminal of the DC power supply at a reference potential point and the voltage of the DC power supply is applied in the reverse direction. And a third and fourth MOS transistor whose conduction and non-conduction are controlled by a control signal provided between the source and the drain and applied to the gate, wherein the first and third MOS transistors are provided. Wherein a connection point of the transistor second,
An H-bridge type output stage circuit for connecting a motor between the connection point of the fourth MOS transistor and driving and controlling the motor;
An H-bridge type motor drive circuit comprising: a control circuit for controlling a level of the control signal in accordance with a rotation control signal to control conduction and non-conduction of the first to fourth MOS transistors. A voltage detection circuit for detecting a voltage at a connection point between the transistors and a connection point between the second and fourth MOS transistors; and controlling the control circuit to turn off one of the first and second MOS transistors from a conductive state. During a predetermined period from the time when the supply of current to the motor is stopped in the conductive state, the third and fourth MOSs are provided.
A transistor having a predetermined conduction resistance and a voltage detected by the voltage detection circuit is connected to the first and second MOs.
It is configured as a circuit that is controlled by the corresponding control signal so that the parasitic diode of the S transistor is kept in a non-conductive range.

[0013] Further, of the third and fourth MOS transistors, a MOS transistor different from the MOS transistor that has supplied the current to the motor is replaced by a predetermined time from when the supply of the current to the motor is stopped. After being kept in a non-conductive state, it is configured to control so as to have a predetermined conductive resistance, and further, the first, second and third MOS transistors and the third and fourth MOS transistors are made to have opposite conductivity types. , And the sources of the first to fourth MOS transistors are connected to first and second power supply terminals of a DC power supply, respectively.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

This embodiment is different from the conventional H-bridge type motor drive circuit shown in FIGS.
1, ie, the connection point (node N1) of the MOS transistors T1 and T3 and the MOS transistors T2 and T4.
Voltage detection circuit 3 for detecting the voltage at the connection point (node N2)
And the control circuit 2 includes MOS transistors T1, T2
The motor M by changing one of the
During a predetermined period (during the energy release period of the motor M1) from the time when the supply of the current to the motor M1 is stopped, the MOS transistors T3 and T4 that have supplied the current to the motor M1 together with one of the MOS transistors T1 and T2. One of the MOS transistors T1 and T2 has a predetermined conduction resistance and the voltage detected by the voltage detection circuit 3 is in a range that keeps one of the MOS transistors T1 and T2 in a non-conductive state. The MOS transistors T3 and T4 are controlled by corresponding control signals (GC4 or GC3).
After a lapse of a predetermined time (t) from the time when the supply of the current to the motor M1 during the predetermined period is stopped, the voltage having the predetermined conduction resistance and detected by the voltage detection circuit 3 is changed. The circuit is controlled by a corresponding control signal (GC3 or GC4) so that the other parasitic diode (D1 or D2) of the MOS transistors T1 and T2 is kept in a non-conductive range.

Next, the operation of this embodiment will be described with reference to the signal waveform diagrams of the respective parts shown in FIG.

First, the control signals GC1 and GC4 are set to the high level of the power supply voltage Vdd to set the MOS transistors T
1, T4 is completely turned on, a current is supplied from the DC power supply E1 to the motor M1 along the route indicated by the solid line a, and the motor M1 is rotated in a predetermined direction (period Ta). This operation is the same as the conventional example shown in FIGS.

Next, the control signal GC1 is set to the low level of the ground potential level, the MOS transistor T1 is turned off, and the supply of the current from the DC power supply E1 to the motor M1 is stopped. (Periods Tb and Tc), the range in which the MOS transistor T4 has a predetermined conduction resistance (higher resistance than when fully turned on) and the voltage at the node N2 keeps the parasitic diode D2 of the MOS transistor T2 non-conductive (for example, Power supply voltage V
dd), and controls the level of the control signal GC4 so that the MOS transistor T3 is turned off by the time t after the supply of the current from the DC power supply E1 to the motor M1 is stopped. The level of the control signal GC3 is set so as to have a higher conduction resistance than when fully turned on and to keep the voltage at the node N1 in a range in which the parasitic diode D1 of the MOS transistor T1 is kept in a non-conductive state (for example, a range not exceeding the power supply voltage Vdd). Control.

As a result, a current due to the energy stored in the inductance component of the motor M1 flows through the path indicated by the dashed line b (accumulated energy release period Tb), and the current generated by the inertia of the motor M1 after the release of the stored energy is generated. The current flows along the path indicated by the alternate long and short dash line c (power generation energy release period Tc). At this time, since the voltages at the nodes N1 and N2 are suppressed such that the parasitic diodes D1 and D2 maintain the non-conductive state, the parasitic thyristor of the CMOS type circuit such as the control circuit 2 formed on the same chip is also conductive ( ON) state, and therefore, the occurrence of a latch-up phenomenon can be prevented. In addition, a MOS transistor T4 having a higher conduction resistance than when fully ON is provided in a path indicated by a broken line b and an alternate long and short dash line c. Since T3 is inserted, the time constant composed of the inductance component of the motor M1 and the resistance components of the MOS transistors T4 and T3 can be reduced, and the energy emission periods Tb and Tc of the motor M1 can be shortened. it can.

In the MOS transistors T1 and T3 connected in series between the power supply terminals of the DC power supply E1, the MOS transistor T1 is turned off (disconnected), and after a lapse of time t, the MOS transistor T3 is turned on (conducted). ), Even if the turning off of the MOS transistor T1 is slightly delayed, these MOS transistors T1, T3
Through current can be prevented. Furthermore,
Since the current for releasing the energy of the motor M1 does not flow through the parasitic transistor D2 of the MOS transistor T2, even if the driving of the next motor M1 is started at the time of releasing the energy and the MOS transistor T4 is turned on, the parasitic transistor D2 Does not cause a reverse recovery phenomenon, so that a through current can be prevented from flowing through the MOS transistors T2 and T4, and a delay in starting the driving of the motor M1 can be prevented.

FIG. 2 shows MOS transistors T1 and T4.
Is turned on to rotate the motor M1 in a predetermined direction. However, when the MOS transistors T2 and T3 are turned on to rotate the motor M1 in the opposite direction to this example, basically, Is similar to the above example.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention, and FIG. 4 is a signal waveform diagram of each part for explaining the operation of this embodiment.

This embodiment is a modification of the MO in the first embodiment.
While S transistors T1 and T2 are N-channel type, P-channel type MOS transistors T1a and T2a
(The MOS transistors T3 and T4 remain N-channel type), and the control circuit 2a is changed so that the levels of the control signals GC1a and GC2a are opposite to the levels of the control signals GC1 and GC2 of the first embodiment. It is.

The basic operation, operation and effect of this embodiment are the same as those of the first embodiment. Further, in this embodiment, M
Since the source serving as a reference for the operation of the OS transistor is connected to the power supply terminal of the DC power supply E1 for all of the MOS transistors T1a, T2a, T3, and T4, there is an advantage that the ON and OFF operations of these MOS transistors can be stably controlled. is there.

In this embodiment, the current for releasing the energy of the motor M1 is supplied to the MOS transistors T1a, T1a,
It goes through T2a (dashed line b, dashed line c),
The same method as in the first embodiment can be used.

[0027]

As described above, the present invention provides a connection point between the first and third MOS transistors, a connection point between the second and fourth MOS transistors connected in series between both power supply terminals of the DC power supply, That is, a voltage detection circuit for detecting the voltage of both terminals of the motor is provided, and the control circuit is turned on when the current is supplied to the motor during the energy release period of the motor.
One of the two MOS transistors is turned off, and the other is a circuit having a predetermined on-resistance and controlling the voltage detected by the voltage detection circuit so that the parasitic diode of the other two MOS transistors is not turned on. Since a parasitic thyristor such as a control circuit formed on the same chip can be prevented from being turned on, the occurrence of a latch-up phenomenon can be prevented. Since the MOS transistor is inserted, the time constant of the energy release route can be reduced by the inductance component of the motor and the resistance component of the MOS transistor. Therefore, the energy release period of the motor, that is, the time required for stopping the motor, is reduced. There is an effect that can be. The current for releasing the energy of the motor is the first and second M.
Parasitic diode of OS transistor or third and fourth MO
Since the operation is performed through the parasitic diode of the S transistor, even if the next motor drive is started during this energy release period, the reverse recovery phenomenon occurs in the parasitic diode in which no current flows for energy release. Does not occur. Therefore, it is possible to prevent a through current from flowing through these MOS transistors, and to shorten the time for starting motor driving.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram of each section for explaining the operation of the embodiment shown in FIG.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a signal waveform diagram of each section for explaining the operation of the embodiment shown in FIG. 3;

FIG. 5 is a circuit diagram showing an example of a conventional H-bridge type motor drive circuit.

6 is a signal waveform diagram of each section for describing the operation of the H-bridge type motor drive circuit shown in FIG.

[Explanation of symbols]

 1 H-bridge type output stage circuit 2, 2a, 2x control circuit 3 Voltage detection circuit D1 to D4 Parasitic diode E1 DC power supply M1 Motor T1 to T4, T1a, T2a MOS transistor

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein one of the source and the drain is connected to a first power supply terminal of a DC power supply, and a parasitic diode to which a voltage of the DC power supply is applied in a reverse direction is provided between the source and the drain and applied to a gate. Conduction by the control signal
First and second MOS transistors whose non-conduction is controlled,
And one of a source and a drain is connected to the other of the source and the drain of the first and second MOS transistors, respectively, and the other is connected to a second power supply terminal of the DC power supply at a reference potential point. A third diode having a parasitic diode to which a voltage of a DC power supply is applied in a reverse direction between a source and a drain, and having a third and fourth MOS transistors whose conduction and non-conduction are controlled by a control signal given to a gate; An H-bridge type output stage circuit for connecting a motor between a connection point of a third MOS transistor and the connection point of the second and fourth MOS transistors to drive and control the motor; An H-bridge type motor drive circuit having a control circuit for controlling the level of the first to fourth MOS transistors to control the conduction and non-conduction of the first to fourth MOS transistors. A voltage detection circuit for detecting a voltage at a connection point between the third MOS transistor and a connection point between the second and fourth MOS transistors, and causing the control circuit to conduct one of the first and second MOS transistors. The third and fourth MOS transistors have a predetermined conduction resistance and are detected by the voltage detection circuit during a predetermined period from a point in time when the supply of current to the motor is stopped by changing the state from a state to a non-conduction state. Voltage is applied to the first and second MOS
An H-bridge type motor drive circuit, wherein the circuit is controlled by the control signal corresponding to a range in which a parasitic diode of the transistor is kept in a non-conductive state. 2. The method according to claim 1, wherein the third and fourth MOS transistors are different from the MOS transistor supplying the current to the motor for a predetermined time from the time when the supply of the current to the motor is stopped. 2. The H-bridge type motor drive circuit according to claim 1, wherein the circuit is controlled to have a predetermined conduction resistance after being kept in a non-conduction state. 3. The first and second MOS transistors and the third and fourth MOS transistors are of opposite conductivity types, and the sources of the first to fourth MOS transistors are respectively connected to the first and fourth DC power sources. 2. The H-bridge type motor drive circuit according to claim 1, wherein the H-bridge type motor drive circuit is connected to a second power supply terminal.