JP2000115997A - Drive control apparatus for load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a drive control apparatus which restrains a rise in costs as far as possible and which reduces an unnecessary power consumption, by a method wherein, on the basis of a control signal used to drive and control a load, the supply of a driving power to a drive control circuit from a power supply circuit is controlled and an ordinary mode and a standby mode are changed over. SOLUTION: A standby circuit 16 outputs a mode changeover signal to a power supply circuit 14 according to the drive command value of a motor 11 which is indicated by a given drive command signal. Then, in the power supply circuit 14, an ordinary mode which supplies a driving power supply VBL to a drive control circuit 13 and a standby mode which stops its supply and which reduces a power consumption are changed over according to the mode changeover signal. At this time, the standby mode refers to a mode in which a current consumed by the power supply circuit 14 is extremely small as compared with that in the ordinary mode, and e.g. a consumed current becomes 1 mA or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load drive control device provided with a drive control circuit for controlling the drive of a load based on predetermined drive conditions.

[0002]

2. Description of the Related Art For example, in the case where a blower motor or a cooling fan motor used for an air conditioner (air conditioner) mounted on an automobile is driven and controlled by a load, unnecessary power consumption during a period when the operation of the motor is stopped is unnecessary. There is a demand to suppress as much as possible.

For this reason, conventionally, as shown in FIG. 14, for example, a controller 4 comprising a power supply circuit 1 and a drive control circuit 2 for controlling the drive of a motor 3 and supplying drive power to the controller 4 There is a device in which a relay 6 is interposed between the battery 5 and the power supply from the battery 1 to the controller 4 and the motor 3 is stopped by turning off the relay 6 when the operation of the air conditioner is stopped.

As shown in FIG. 15, an on / off signal of the ignition switch 7 is input to the controller 4 so that the power supply circuit 1 is operated under the condition that the ignition switch 7 is turned on.
To supply power to the controller 4 and the motor 3 from the controller.

[0005]

However, FIG.
In the method shown in (1), since a relatively large current flows through the relay 6 when the relay is closed (ON), a large-sized relay that can withstand the current is required, and the cost increases. FIG.
In the method shown in FIG. 5, it is necessary to provide a terminal (port) for inputting the signal of the ignition switch 7 to the controller 4 independently, and there is also a problem that the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a load drive control device capable of suppressing unnecessary power consumption while suppressing an increase in cost as much as possible. is there.

[0007]

According to the load drive control device of the first aspect, the mode switching means switches from the power supply circuit to the drive control circuit based on a control signal for performing load drive control. Switching between the normal mode and the standby mode for reducing power consumption is performed by controlling the supply of the driving power. Therefore, unlike the related art, it is possible to perform switching between the normal mode and the standby mode without using a large-sized relay or providing an ignition switch on / off signal to the drive control circuit. Unnecessary power consumption can be reduced.

According to the load drive control device of the second aspect, the mode switching means supplies the drive power from the power supply circuit to the drive control circuit based on the control signal for controlling the drive of the load. By performing control, switching between the normal mode and the standby mode in which power supply is stopped is performed. Therefore, similarly to the first aspect, unlike the related art, it is possible to switch between the normal mode and the standby mode without using a large-sized relay or providing an ON / OFF signal of the ignition switch to the drive control circuit. Unnecessary power consumption can be reduced by suppressing an increase in cost.

According to the load drive control device of the third aspect, the mode switching means switches the charging and discharging of the capacitor according to the level of the control signal by the charging and discharging switching circuit, and normally switches the voltage based on the terminal voltage of the capacitor. The mode is switched between the standby mode and the standby mode. For example, if the control signal is a signal that specifies the drive condition of the load according to the signal level, the charge / discharge switching circuit charges the capacitor when the signal level exceeds the reference voltage, and discharges the capacitor when the signal level falls below the reference voltage. Set to

When the terminal voltage of the capacitor falls below a predetermined level, a transition is made from the normal mode to the standby mode, so that a specific load driving condition indicated by the control signal is set as a mode switching threshold value. By shifting to the mode, power consumption can be reduced. Further, by performing mode switching based on the terminal voltage of the capacitor, even if external noise is applied, the level can be smoothed to eliminate the influence, and the switching operation can be performed reliably.

According to a fourth aspect of the present invention, when the control signal is a signal for changing the duty ratio of the pulse signal in accordance with the driving condition of the load, the charge / discharge current between the charge and discharge circuits is controlled. Is set in advance so as to be substantially equal to the duty ratio corresponding to the mode switching threshold value, for example, when the duty ratio of the control signal matches the value corresponding to the threshold value. Means that the terminal voltage of the capacitor is substantially constant.

If the switching of the charge / discharge switching circuit is set so that the terminal voltage of the capacitor falls when the duty ratio of the control signal falls below a value corresponding to the threshold value, for example, Similarly, it is possible to shift to the standby mode using a specific load driving condition designated by the control signal as the threshold value.

According to the load drive control device of the fifth aspect, the duty ratio corresponding to the mode switching threshold value is
Since the duty ratio is set to be smaller than the duty ratio corresponding to the load driving start condition, for example, the load can be quickly started by shifting from the standby mode to the normal mode before the load driving start condition is satisfied. it can.

According to a sixth aspect of the present invention, when the control signal is a signal for changing the frequency of the pulse signal in accordance with the driving condition of the load, the mode switching means sets the frequency of the pulse signal. The switching between the normal mode and the standby mode is performed according to the level of the signal.
The same effect can be obtained.

According to the load drive control device of the present invention, when the control signal is a serial signal whose level changes digitally in accordance with the drive condition of the load, the mode switching means controls the serial signal. Is converted into a parallel signal, and switching between the normal mode and the standby mode is performed based on the data value of the parallel signal. Therefore, the same effect as that of the third aspect can be obtained.

According to the load drive control device of the present invention, the mode switching means changes the transition timing between the normal mode and the standby mode according to the change of the main power supply voltage. When the driving power is supplied as the main power supply, the transition timing from the standby mode to the normal mode is delayed when the main power supply voltage is reduced to some extent according to the use state of the battery. By making the transition timing from the standby mode to the standby mode earlier, it is possible to suppress the power consumption of the battery and prolong the usable time.

According to the load drive control device of the ninth aspect, when the mode switching means detects that the drive of the load has shifted to the stop state by the control signal output from the load drive state detection means, the mode switching means switches from the normal mode to the standby mode. Since the mode is shifted to the mode, the mode can be shifted to the standby mode at an appropriate timing when the driving of the load is substantially stopped.

According to the load drive control device of the tenth aspect, the mode switching means shifts from the normal mode to the standby mode even when the control signal detects that the load drive has become abnormal. I do. Therefore, for example, when the load is a motor, if an abnormality such as an overcurrent flows into the motor or the motor is locked, the power supply to the drive control circuit is stopped by shifting to the standby mode. Thus, the load can be protected and the power consumption can be reduced.

According to the load drive control device of the eleventh aspect, the control state detecting means detects the control state of the drive control circuit and outputs a control signal based on the control state.
The mode switching means shifts from the normal mode to the standby mode when detecting that the control of the drive control circuit is in an abnormal state by the control signal. Therefore,
For example, when the elements constituting the drive control circuit are overheated, the mode is shifted to the standby mode and the power supply to the drive control circuit is stopped, so that the drive control circuit can be protected and the power consumption can be reduced. .

According to the load drive control device of the twelfth aspect, the voltage drop compensation circuit includes a plurality of switching elements forming a power supply circuit based on a boosted output of a booster circuit that performs a boost operation of a drive power supply voltage. Compensates for the effect of the voltage drop of the driving power supply, so that the voltage of the driving power supply can be supplied to the drive control circuit while maintaining the voltage higher.
The use efficiency of the power supply can be improved.

According to the load drive control device of the thirteenth aspect, the power supply generation circuit boosts the drive power supply voltage supplied from the power supply circuit by the booster circuit and generates the drive power supply voltage generated by using the boosted output. Since the power supply is supplied to the drive control circuit, a drive power supply having a sufficient voltage level can be supplied, and the use efficiency of the power supply can be improved as in the eleventh aspect.

According to the load drive control device of the present invention, the power supply generation circuit starts the operation of the booster circuit when the mode switching means shifts from the standby mode to the normal mode. It operates only when needed, and power consumption can be reduced.

According to the load driving control device of the present invention, when the braking means is in the state of transition to the standby mode by the mode switching means, any one of the plurality of switching elements constituting the driving circuit is provided. Turning on one or more brakes the load. Therefore, when the load is, for example, a fan motor for rotating a fan, the fan motor may be rotated by an external force such as wind even when the fan motor is not controlled by the drive control circuit. is assumed. Even in such a case, the rotation can be stopped by braking the fan motor by the braking means, and the generation of unnecessary electromotive force and noise can be prevented.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
A first embodiment in which the invention is applied to a blower motor of an air conditioner (car air conditioner) mounted on an automobile will be described with reference to FIGS. FIG.
FIG. 3 is a functional block diagram illustrating an electrical configuration. In FIG. 4, for example, a fan 12 of a car air conditioner is attached to a rotating shaft of a motor (load) 11 composed of a brushless motor. The fan 12 is arranged inside the front of the automobile, and is driven to rotate by the motor 11 and blows, for example, air cooled by an evaporator (not shown) into the vehicle interior.

The drive of the motor 11 is controlled by a drive control circuit 13. The drive control circuit 13 is supplied with a drive power supply VBL from a power supply circuit 14 using a vehicle battery 15 (Batt) as a main power supply VB. The power supply circuit 14 is directly connected to the battery 15 without using a switch such as a relay. A drive command signal (control signal) for designating the number of rotations of the motor 11 is externally supplied to the drive control circuit 13 and the standby circuit (mode switching means) 16.

The standby circuit 16 outputs a mode switching signal to the power supply circuit 14 in accordance with the drive command value of the motor 11 indicated by the given drive command signal. In response to the mode switching signal, the power supply circuit 14 switches between a normal mode in which the drive power supply VBL is supplied to the drive control circuit 13 and a standby mode in which the supply is stopped to reduce power consumption. It has become. Here, the standby mode is a mode in which the current supplied from the battery 15 shown in FIG. 4 and consumed by the drive control circuit 13 and the power supply circuit 14 is much smaller than that in the normal mode. , The current consumption is 1 mA or less.

FIG. 2 shows a more detailed electrical configuration of the drive control circuit 13. 2, the drive control circuit 13 includes a control circuit 17 mainly composed of a microcomputer and a drive circuit 18. The drive circuit 18 is an n-channel power MOSFET
(Switching element, hereinafter simply referred to as FET) is constituted by an inverter in which 19 to 24 are connected in a three-phase bridge. A freewheel diode (not shown) is connected (or integrally formed as an element) between the source and the drain of each of the FETs 19 to 24.

The positive bus 18a of the drive circuit 18 is directly connected to the battery 15 (Batt). The power supply terminal of the control circuit 17 is connected to the power supply terminal of the power supply circuit 14, and the negative bus 18b of the drive circuit 18 is connected to the ground. The control circuit 17 has a control power supply circuit (not shown) built therein.
4, a control power supply of, for example, about 5 V is generated from a drive power supply VBL of, for example, about 14 V, and supplied to an internal circuit.

In the motor 11, three-phase stator coils 11u, 11v and 11w are connected in a [Delta] -connection, and a common connection point of the coils 11u and 11v, 11v and 11w, 11w and 11u has a drive circuit 18 Output terminal 1
8u, 18v and 18w are connected respectively. The output terminals of a braking circuit (braking means) 25 are connected to the gates of the FETs 22 to 24 constituting the negative side arm of the driving circuit 18, respectively. The main power supply VB is directly supplied from the battery 15 to the braking circuit 25.

When the mode switching signal provided by the standby circuit 16 indicates the standby mode, the braking circuit 25 drives the gates of the FETs 22 to 24 instead of the gate driving circuit built in the control circuit 17. Has become. In the normal mode, the output terminal of the braking circuit 25 is configured to be in a high impedance state.

FIG. 1 shows the electrical configuration of the standby circuit 16 in more detail. In FIG. 1, the battery 15 is connected to the I0 / VREF generation circuit 26 of the standby circuit 16. I0 / VREF generation circuit 26
Generates a constant current I0 and a reference voltage VREF from a power supply supplied from the battery 15, and supplies the constant current I0 and the reference voltage VREF to each part of the standby circuit 16 as appropriate.

The reference voltage VREF output from the I0 / VREF generating circuit 26 is supplied to a non-inverting input terminal of a first comparator 27, and a driving command signal is externally supplied to the inverting input terminal of the first comparator 27. Is to be given. The output terminal of the first comparator 27 is provided to the charge / discharge switching circuit 28 as a switching control signal.

Here, the drive command signal is a signal for designating the number of revolutions of the motor 11 by, for example, a low-level duty ratio of a pulse signal (see FIG. 5).
In No. 3, when the duty ratio becomes equal to or more than 20% (drive start condition), the drive of the motor 11 is started to control the rotation speed.

The charge / discharge switching circuit 28 includes a charging circuit 29,
It comprises a discharge circuit 30 and a switching control circuit 31. The switching control circuit 31 represented by the symbol of the switching switch connects the other end (output terminal 31 a) of the capacitor 32 having one end connected to the ground in accordance with the switching control signal output from the first comparator 27. One end of the charging circuit 29 or the discharging circuit 30 (input terminal 31b
Alternatively, switching is performed so as to connect to 31c). Incidentally, the switching control circuit 31 is actually configured by a transistor or the like.

The other ends of the charge and discharge circuits 29 and 30 are connected to the battery 15 and the ground, respectively.
The ratio of the charge / discharge current to the capacitor 32 is set in advance so as to be substantially equal to the duty ratio of the drive command signal corresponding to the threshold (mode switching threshold) for switching between the normal mode and the standby mode. Is set.

For example, when the duty ratio of the drive command signal corresponding to the mode switching threshold is 5%, when the charging circuit 29 is connected to the capacitor 32 via the switching control circuit 31 (31b → 31a). , Condenser 32
Is set to 190 μA by charging the battery 15 with the battery 15, and the discharge circuit 30 controls the switching control circuit 31 (31
When connected to the capacitor 32 via c → 31a), the current value for discharging the charge charged in the capacitor 32 to the ground is set to 10 μA. That is, the ratio of the charge / discharge current (discharge current value / (charge current value + discharge current value)) = 1
0 / (190 + 10) = 5%.

The output terminal 31a of the switching control circuit 31
The non-inverting input terminal of the second comparator 33 is connected to the non-inverting input terminal of the second comparator 33.
The reference voltage VREF output from the / VREF generation circuit 26 is applied. An output terminal of the second comparator 33 is connected to a control signal terminal of the power supply circuit 14 represented by an on / off switch symbol via an inverter 34, and outputs a mode switching signal to the power supply circuit 14. To give. Then, as described above, the power supply circuit 14 responds to the mode switching signal
It switches between a normal mode in which the drive power supply VBL is supplied from the battery 15 to the drive control circuit 13 and a standby mode in which the supply is stopped.

FIG. 3 shows a detailed electrical configuration of the power supply circuit 14. npn transistor 34a
Is a component of the inverter 34, and receives an output signal of the second comparator 33 at a base via a resistor. The collector of the transistor 34a is I0
/ VREF generating circuit 26, which is connected to the collector of a pnp-type transistor 26a for supplying a constant current I0 to supply a constant current I0 and a resistor (not necessarily required). Is connected to the base of an npn-type transistor 35 via the. The emitter of the transistor 34a is connected to the ground (GND).

The collector of the transistor 35 is connected to a resistor 36.
a and a battery 36 (Bat) via a series circuit of 36b.
t) and to the collector of transistor 37. The emitter of the transistor 35 is connected to ground via a resistor and to the base of an npn transistor 37. The emitter of the transistor 37 is connected to the ground.

The common connection point of the resistors 36a and 36b is connected to the base of a pnp transistor 38 whose emitter is connected to the battery 15. The collector of the transistor 38 is connected to the base of an npn-type transistor 39 and to the emitter of the transistor 39 via a resistor. Transistor 3
The collector of the transistor 9 is connected to the battery 15, and the emitter of the transistor 39 supplies the drive power supply VBL to the drive control circuit 13.

Next, the operation of this embodiment will be described with reference to FIG. For example, as shown in section A of FIG.
As an initial state, no drive command signal is output (low level duty ratio 0%), the rotation of the motor 11 is stopped, and the level of the mode switching signal is low.
Therefore, the power supply circuit 14 stops supplying the driving power supply VBL from the battery 15 and is in the standby mode (see FIG. 6C).

From this state, it is assumed that the operation of the car air conditioner is started, a predetermined amount of air is blown by the fan 12, and the number of revolutions of the motor 11 is designated by a drive command signal having a duty ratio of about 60% (FIG. 6, FIG. 6). Section B). When the level of the drive command signal is lower than the reference voltage VREF (3.75 V), the second comparator 33 outputs a low level signal.
When the voltage is higher than the reference voltage VREF, a switching control signal having a high level is output to the switching control circuit 31.

The switching control circuit 31 connects the capacitor 32 to the charging circuit 29 and the discharging circuit 30 according to the low and high levels of the switching control signal. Then, as shown in FIG. 6B, the capacitor 32 is charged with a current of 190 μA when the switching control signal is at a low level, and the charged charge becomes 1 when the switching control signal is at a high level.
Discharged at a current of 0 μA.

Here, the duty ratio of the drive command signal is 5
%, (Charge current value) × (charge time: low level period) = (discharge current value) × (discharge time: high level period), so that the terminal voltage of the capacitor 32 does not change from the initial value. Then, the duty ratio of the drive command signal is 5%.
Is exceeded, (left side)> (right side) in the above equation, the charge amount exceeds the discharge amount, and the terminal voltage of the capacitor 32 rises from the initial value. In this case, the duty ratio is small (that is, the rotational speed command for the motor 11 is low).
The transition from “standby to normal” is slower as the duty ratio is larger (that is, the rotational speed command for the motor 11 is higher) as the duty ratio is larger.

Therefore, as shown in FIG. 6 (b), the terminal voltage of the capacitor 32 rises from 0V, and the reference voltage VREF
Is exceeded, the second comparator 33 sets the output signal to low level. Then, the transistor 34a constituting the inverter 34 is turned off, and the constant current I0 is supplied to the transistor 35 of the power supply circuit 14 via the transistor 26a, so that the base current flows.
5 turns on.

When the transistor 35 is turned on, the base current is also supplied to the transistor 37, and the transistor 37 is also turned on. Then, the transistor 38 is turned on by the base current flowing, and the transistor 38 is also turned on in the same manner, so that the power supply circuit 14
To supply the drive power supply VBL to the drive control circuit 13, and shift from the standby mode to the normal mode (FIG. 6, section B → C).

On the other hand, when the operation of the car air conditioner is stopped from the state of the normal mode and the duty ratio of the drive command signal falls below 5%, the capacitor 32 is discharged via the discharge circuit 30 and the terminal voltage of the capacitor 32 becomes the second voltage. When the voltage falls below the threshold value (reference voltage VREF) of the second comparator 33, the second comparator 33 sets the switching control signal to low level. Then, the power supply circuit 14 shifts from the normal mode to the standby mode, and stops supplying the drive power supply VBL to the drive control circuit 13 (FIG. 6, section D → E).

Further, once the mode shifts to the normal mode, the reference voltage VREF given by the I0 / VREF generation circuit 26 is slightly reduced in order to provide hysteresis when the mode shifts to the standby mode. (See FIGS. 6B and 6C). Therefore, as shown in the section D, even if the duty ratio of the drive command signal is suddenly set to 0%, the state does not immediately shift from “normal to standby”.

Next, the drive control circuit 13 and the braking circuit 25
A description will be given of the operation centered on. Drive control circuit 13
Is supplied with driving power in the normal mode, and when the fan 12 is rotated via the motor 11, the control circuit 17 detects the rotation position of the rotor of the motor 11 by a position sensor or the like (not shown), and detects the rotation position. Each of the FETs constituting the drive circuit 18 at an appropriate timing according to
The motor 11 is driven by giving gate signals having a phase difference of, for example, 120 degrees to each of the 19 to 24 gates for each phase. The drive timing is based on a known method.

Here, FIG. 7 shows only a part of a configuration example of the gate drive circuit 40 built in the control circuit 17. The gate drive circuit 40 includes a p-channel MOSF
The FET 40a is configured by a CMOSFET including an ET 40a and an n-channel MOSFET 40b.
And the source of the FET 40b is connected to the ground. The drains of both FETs 40a and 40b are connected to the gate of FET 22.

In the normal mode, when a low-level control signal is applied to the gates of both FETs 40a and 40b, the FET 40a is turned on and the FET 40b is turned off, so that the gate level becomes high and the FET 22 is turned on.
In this case, since all of the FETs constituting the drive circuit 18 are driven by voltage, current consumption hardly occurs.

By the way, in the standby mode,
Since the drive power supply VBL is not supplied to the drive control circuit 13 itself, the gate drive circuit 40 cannot control the FET 22. Therefore, when a high-level mode switching signal indicating the standby mode is given from the standby circuit 16, the braking circuit 25 drives the gates of the FETs 22 to 24 to a high level to drive the FET 22.
To 24, each phase winding 1 of the motor 11 is turned on.
Both ends of 1u, 11v and 11w are connected to the ground. In this case, the braking circuit 25 may continuously drive the gates of the FETs 22 to 24 during the standby mode, or may drive the gates intermittently at regular intervals.

As described above, in the standby mode, the operation of the braking circuit 25 causes the drive control circuit 13 to operate.
Motor 11 in a state where no driving torque is given by
On the other hand, for example, when the automobile runs, the fan 12
In the case where an external force acts to rotate the motor 11 in response to wind, the braking can be applied by connecting both ends of the phase windings 11u, 11v and 11w to the ground.

As described above, according to this embodiment, when the level of the drive command signal for designating the rotation speed of the motor 11 by the duty ratio of the pulse signal falls below the reference voltage VREF, the standby circuit 16 is switched to the charge / discharge switching circuit 28. To charge the capacitor 32, and discharge the capacitor 32 when the voltage exceeds the reference voltage VREF. When the terminal voltage of the capacitor 32 falls below the reference voltage VREF, the power supply circuit 14 is set.
Then, the supply of the drive power supply VBL to the drive control circuit 13 is stopped to shift from the normal mode to the standby mode.

Accordingly, the drive condition (rotational speed) of the motor 11 specified by the drive command signal can be determined and the mode can be shifted to the standby mode. There is no need to use a relay or the signal of an ignition switch to stop the supply, and the power consumption can be reduced without increasing the cost by increasing the number of components and the number of input signals.

Since the mode is switched by comparing the terminal voltage of the capacitor 32 with the reference voltage VREF, even if external noise is applied to the standby circuit 16, the level is smoothed by the capacitor 32 and affected. Can be eliminated, and the mode switching operation can be reliably performed.

Since the ratio of the charge / discharge current between the charge / discharge circuits 29 and 30 is set to be equal to the duty ratio corresponding to the mode switching threshold of the drive command signal, the duty ratio of the pulse signal By specifying the driving conditions of the load, the threshold value is determined and switching between the normal mode and the standby mode is performed even when a signal format in which a malfunction due to the influence of noise or the like is unlikely to be employed as in the present embodiment. be able to.

Further, according to the present embodiment, the duty ratio corresponding to the mode switching threshold value is set smaller than the duty ratio corresponding to the drive start condition of the motor 11, so that the drive start condition is not satisfied. At the same time, the drive control circuit 13
Since the driving power supply VBL can be supplied to the motor 11, the motor 11 can be quickly started when the driving start condition is satisfied.

In this embodiment, the power supply from the power supply circuit 14 to the drive control circuit 13 is stopped in the standby mode.
From the drive control circuit 13 directly or from the drive control circuit 13 via the power supply circuit 14 (for example,
The operation of a constant current circuit or the like may be stopped.

(Second Embodiment) FIGS. 8 and 9 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Only the parts will be described. The second embodiment improves the disadvantage of the power supply circuit 14 in the first embodiment. That is, in FIG. 3, the power supply circuit 14 shifts from the standby mode to the normal mode, and the drive control circuit 13
When supplying BL, as described above, the power supply VB of the battery 15 is connected to the transistors (switching elements) 38 and 3.
9 is supplied as a driving power supply VBL.

In this case, the voltage of the driving power supply VBL drops from the voltage of the power supply VB of the battery 15 by the collector-emitter voltage VCE of the transistor 38 and the base-emitter voltage VBE of the transistor 39.
That is, since VBL = VB-VCE (Tr38) -VBE (Tr39) (1), the voltage of the driving power supply VBL is lowered by about 1 V from the voltage of the power supply VB. Therefore, in the second embodiment, a voltage drop compensating circuit 41 for compensating the above voltage drop is added to the power supply circuit 14. Hereinafter, the configuration and operation of the voltage drop compensation circuit 41 will be described.

In FIG. 8, a power supply output line of a power supply circuit 14 for supplying a drive power supply VBL is set as a power supply bus PL.
The booster circuit 42, which is a main part of the voltage drop compensation circuit 41, is configured as follows. Note that, unless otherwise specified, transistors are npn-type. The collectors of the two transistors 43a and 43b connected in parallel are connected to the power supply bus PL via a resistor, and the emitters are connected to ground. A clock signal for controlling the boosting operation is externally supplied to the bases of the transistors 43a and 43b. The clock signal is supplied from a clock generation circuit which is supplied with power from the power supply bus PL.

The collectors of the transistors 43a and 43b are connected to two transistors 44 connected in parallel.
a and 44b and 45a and 45b are connected via resistors, respectively. The collectors of the transistors 44a and 44b are connected to the output line PDL via a series circuit composed of two resistors, and are connected to the bases of the two transistors 46a and 46b connected in parallel. The emitter of 44b is connected to the ground.

The collectors of the transistors 45a and 45b are connected to the emitters of the transistors 46a and 46b via a series circuit composed of two resistors 47a and 47b, and the bases of the transistors 45a and 45b are connected to the ground via the resistors. And the emitter is directly connected to ground.

Two transistors 4 connected in parallel
8a and 48b and 49a and 49b are diode-connected, respectively, and the emitters of the transistors 48a and 48b are connected to the power supply bus PL.
The collectors of a and 49b are connected to ground via a capacitor 50. The collectors of the transistors 48a and 48b are connected to the transistors 49a and 49b
, And to the common connection point of the resistors 47a and 47b via both terminals 51a and 51b of the capacitor 51.

The collectors of the transistors 49a and 49b are connected to the boosted voltage output line PDL and to the collector of the transistor 52.
The collector of the transistor 52 is connected to its own base and the collector of the transistor 53 via a resistor. The series circuit of the resistors 54a and 54b is connected to the power bus PL.
And a ground, and a common connection point between the two is connected to the base of the transistor 53. The emitters of the transistors 52 and 53 are connected to the ground. The above constitutes the booster circuit 42.

The transistors 55 and 56 are configured symmetrically to the transistors 35 and 37, and the base of the transistor 55 is connected to the collector of the transistor 34a via a resistor. The collectors of the transistors 55 and 56 are connected to an output line PDL via a series circuit of resistors 57a and 57b. The emitter of the pnp transistor 58 is connected to the output line PDL, and the base is connected to the common connection point of the resistors 57a and 57b. The emitter of the transistor 58 is connected to the power supply bus PL via a series circuit of resistors 59a and 59b.

The common connection point of the resistors 59a and 59b is connected to two transistors 60a and 60b connected in parallel.
And the transistors 60a and 60
The emitter and collector of Ob are connected to the emitter and collector of the transistor 39, respectively. A voltage drop compensating circuit 41 is formed by adding the above to the boosting circuit 42.

Next, the operation of the second embodiment will be described with reference to FIG. In the following description, the voltage drop due to the resistance is ignored. First, a clock signal of, for example, about 35 KHz is externally applied to the bases of the transistors 43a and 43b (see FIG. 9A), and the transistors 43a and 43b turn on and off in synchronization with the clock signal. Therefore, the transistors 43a and 43
The potential of the collector 3b is substantially at the ground level when the level of the clock signal is high, and is substantially at the VBL level when the level of the clock signal is low (see FIG. 9B).

When the collector potentials of transistors 43a and 43b are substantially at the VBL level, transistor 45
Since a and 45b are turned on and transistors 44a and 44b are turned on and transistors 46a and 46b are turned off, the potential of the terminal 51b of the capacitor 51 is substantially at the ground level. At this time, the terminal voltage VC of the capacitor 51 is charged to approximately VBL level VC = VBL-VF (Tr48) -VCE (Tr45) (2) via the transistors 48a and 48b.

When the potential is substantially at the ground level,
Transistors 45a and 45b are off, transistor 4
4a and 44b are off, transistors 46a and 46b
Is turned on, and the potential becomes approximately VBL level potential = VBL−VCE (Tr46) (3) (see FIG. 9C).

Accordingly, the potential of the terminal 51a of the capacitor 51 is substantially VBL level when the potential is substantially at ground level. Potential = VBL-VF (Tr48) -VCE (Tr45) (4), and the potential is substantially VBL level. At the time of (3) + (4)
As a result, the potential is approximately twice as high as VBL. Potential = VBL−VCE (Tr46) + VBL−VF (Tr48) −VCE (Tr45) (5) Since the potential is the potential −VF (Tr49), the approximate voltage is , Potential = 2 (VBL−VF−VCE) (6)

Since the capacitor 50 is charged by the potential, its terminal voltage gradually increases as shown in FIG. 9E, assuming that the power supply is used in a state where the power supply is smaller than the supplied power. Typically 2 (VBL-VF
−VCE).

When the mode switching signal goes to a low level indicating transition to the normal mode, the transistors 35 and 55 are simultaneously turned on, so that the transistors 38 and 39 of the power supply circuit 14 are simultaneously turned on. Transistors 58 and 60a and 60b of voltage drop compensation circuit 41
Turns on.

At this time, the transistors 58 and 60a and 60b operate at the voltage 2 (VBL-VF-VCE) sufficiently higher than the supply voltage VBL from the power supply circuit 14, and the operation in the saturation region is performed. It becomes possible. Therefore, finally, the power supply bus PL, that is, the drive control circuit 13
Is supplied as VBL '= VB-VCE (Tr60) (7), so that it is possible to compensate for the voltage drop occurring in the power supply circuit 14.

The boosted output (potential) obtained from the booster circuit 42 drives the FETs 19 to 21 serving as the high-side switches (upper arms) of the drive circuit 18 shown in FIG. Each is output to the gate as a gate signal.

As described above, the voltage drop compensating circuit 41 and the boosting circuit 42 are circuits that start operating when the power supply circuit 14 operates, and are driven by the power supply circuit PL when the power supply circuit 14 operates. The boosting operation becomes possible only after the power supply VBL is supplied. That is, the boost operation is performed after the transition from the standby mode to the normal mode, and unnecessary power consumption can be suppressed.

When the boosted output from the booster circuit 42 is supplied to the output line PDL, the transistors 38 and 39 of the power supply circuit 14 are cut off. That is,
The voltage drop compensating circuit 41 generates a driving power supply VBL ′ and supplies the driving power supply VBL ′ to the drive control circuit 13 with the start of the supply of the driving power supply VBL from the power supply circuit 14 as a trigger. The combination with the voltage drop compensation circuit 41 constitutes the power supply generation circuit 100.

On the other hand, when shifting from the normal mode to the standby mode, the transistor 34a is turned on by the mode switching signal, and the transistors 38 and 3 are turned off by turning off the transistors 35 and 37 and the transistors 55 and 56.
9 and the transistors 58, 60a, 60b are turned off, so that the drive power supply VBL 'cannot be generated, and the power supply to the drive control circuit 13 is stopped.

At this time, the clock signal from the clock generating circuit is stopped by the mode switching signal, the transistor 53 is turned off by the potential of the power supply bus PL being lowered, and is stored in the capacitor 50 by the transistor 53 being turned on. The discharged charge is discharged.

As described above, according to the second embodiment, the power supply circuit 14 is provided with the voltage drop compensating circuit 41, or these are used as the power supply generation circuit 100, and the driving circuit supplied from the power supply circuit 14 Supply the power supply voltage VBL to the booster circuit 4
2, the transistors 58 and 60a and 60b are operated based on the boosted output substantially doubled, so that the voltage drop occurring in the power supply circuit 14 can be compensated for, or the driving power supply having a higher voltage can be compensated. V
BL ′ can be generated and supplied to the drive control circuit 13, so that the use efficiency of the battery 15 can be improved. The transistors 58 and 60a and 60b
May be replaced with an N-channel MOSFET.

(Third Embodiment) FIG. 10 shows a third embodiment of the present invention. The format of the drive command signal (control signal) in the third embodiment is different from that in the first and second embodiments in which the number of rotations of the motor 11 is designated by the duty ratio of the pulse signal, and the frequency of the pulse signal is different. Is changed and specified. For example, the rotational speed of the motor 11 is increased as the frequency of the pulse signal increases. The standby circuit (mode switching means) 61 is configured by a pulse number counter that counts the number of drive command signal pulses input within a predetermined time. Other configurations are the same as in the first embodiment.

According to the third embodiment configured as described above, the rotational speed command for the motor 11 decreases, and the pulse input number counted by the standby circuit 61 determines that the command is near zero. By setting the mode to shift from the normal mode to the standby mode when the power consumption drops to a sufficient level, the same effect as in the first embodiment can be obtained.

(Fourth Embodiment) FIG. 11 shows a fourth embodiment of the present invention. The format of the drive command signal (control signal) in the fourth embodiment is different from that of the first to third embodiments, and the motor 11 is controlled by a serial signal having a predetermined number of bits.
This specifies the number of rotations. That is, the number of rotations is designated by a bit string pattern in which the level of the serial signal changes digitally (binary Hi and Lo). The standby circuit (mode switching means) 70 converts the input serial signal into, for example, 4-bit parallel data, shifts to the normal mode when the data value reaches a predetermined value, and when the data value falls below the predetermined value. Switch to shift to standby mode.

The data converted in parallel by the standby circuit 70 is supplied to the drive control circuit 13 via the D / A conversion circuit 71. The operation relating to the drive control of the motor 11 after the D / A conversion circuit 71 is the same as in the other embodiments. According to the fourth embodiment configured as described above, switching between the standby mode and the normal mode can be performed based on the drive command signal.

(Fifth Embodiment) FIG. 12 shows a fifth embodiment of the present invention. The standby circuit (mode switching means) 62 in the fifth embodiment not only refers to the state of the drive command signal as in the first to third embodiments, but also, for example, a sensor (for directly detecting the rotation speed of the motor 11). Reference is also made to a detection signal (control signal) by a load drive state detection means 63 (for example, a Hall IC for detecting the rotational position of the rotor).

The standby circuit 62 is formed around a counter, for example, similarly to the standby circuit 61 of the third embodiment.
The number of rotations of the motor 11 is directly detected by counting the number of pulses of a detection signal output with the rotation of the rotor (for example, every 120 electrical degrees). Other configurations are the same as in the first embodiment.

According to the fifth embodiment configured as described above, the number of revolutions of the motor 11 decreases, and the pulse input number counted by the standby circuit 62 determines that the number of revolutions is near zero. The same effect as in the third embodiment can be obtained by setting the mode to shift from the normal mode to the standby mode when the power consumption drops to a sufficient level.

The control signal in the present invention broadly means a signal used for controlling the driving of the load, and specifically, as described in the above embodiment, The drive state or control state of the motor, such as a drive command signal given from outside to specify the number of rotations of the motor or a position detection signal of the sensor 63 required when the drive control circuit 13 controls the drive of the motor 11 Indicates a signal that reflects such factors.

The present invention is not limited to the embodiment described above and shown in the drawings, and the following modifications or extensions are possible. When the duty ratio of the drive start condition in the control signal is 20%, the duty ratio of the mode switching threshold is not limited to 5%, and may be set to, for example, 3% or 10%. . In addition, 20%
May be set. Instead of the gate drive circuit 40 composed of a CMOSFET, a gate drive circuit 64 composed of a bipolar transistor may be arranged as shown in FIG. The drive power supply VBL supplied from the power supply circuit 14 is applied to the collector of the npn-type transistor 65 constituting the gate drive circuit 64, and its base is connected via a resistor. The base of the transistor 65 is connected to the base of the pnp transistor 66 and the collector of the npn transistor 67.

The emitter of the transistor 65 is connected to the emitter of the transistor 66 and the gate of the FET 22. The collector of the transistor 66 and the emitter of the transistor 67 are connected to the ground. The gate of the FET 22 has a braking circuit (braking means) 6.
8 is connected to the collector of a pnp transistor 68a. The emitter of the transistor 68a is
The power supply VB of the battery 15 is supplied.

The gate drive circuit 6 configured as described above
When a high-level signal is applied to the base of the transistor 67, the transistors 67 and 66 are turned on and the transistor 65 is turned off. Accordingly, the gate of the FET 22 becomes low level and is turned off. In addition, transistor 6
When a low-level signal is supplied to the base of the transistor 7, the transistors 67 and 66 are turned off and the transistor 65 is turned on, so that the gate of the FET 22 is turned on at the high level.

In the standby mode, since the driving power supply VBL is not supplied to the gate driving circuit 64, a low-level signal is supplied to the base of the transistor 68a by the control unit (not shown) of the braking circuit 68 (for example, For example, pulling the base with a current of about 10 μA) drives the gates of the FETs 22 to 24 to a high level to turn on the FETs 22 to 24. in this case,
Like the braking circuit 25, during the standby mode, the FET
The gates 22 to 24 may be driven continuously or intermittently at regular intervals. When the gate drive circuit 64 and the braking circuit 68 are configured as described above, the same effects as those of the first embodiment can be obtained.

The drive command signal is not limited to the signal for specifying the rotation speed of the motor 11 by changing the duty ratio of the pulse signal, but may be a signal for specifying the rotation speed by changing the signal level. Even when such a type of drive command signal is externally supplied, the standby circuit 1 in the first embodiment is provided.
6 can be applied as it is by appropriately adjusting the level of the reference voltage VREF. For example, when the signal level of the drive command signal exceeds a mode switching threshold given by the reference voltage VREF, the capacitor 32 is continuously charged by the output signal of the first comparator 27, and the terminal voltage thereof rises. And the second comparator 3
3, the mode switching signal is output so as to shift from "standby to normal". Conversely, when the signal level of the drive command signal falls below the mode switching threshold, the capacitor 32 is continuously discharged, so that the mode switching is performed so that the terminal voltage falls and shifts from "normal to standby". A signal is output.

Further, the mode switching means is provided by the battery 15
By referring to the terminal voltage VB, when the terminal voltage VB decreases to some extent in accordance with the use state of the battery 15, the transition timing from "standby to normal" is further delayed, and "normal to standby" It is preferable to adjust the level of the reference voltage VREF so that the timing of transition to "" becomes earlier. With such a configuration, it is possible to suppress the power consumption of the battery 15 and prolong the usable time. The switching elements constituting the drive circuit are not limited to the FETs 19 to 24, but may be bipolar transistors or IGBTs. However, the braking circuit 25 is not limited to this. Other examples of the load drive state detection means include, for example,
A current detector that detects a motor current to detect a drive state such as lock or overcurrent of the motor 11 may be used, and the current detection signal may be used as a control signal. Further, as the control state detecting means, the FET1 of the drive circuit 18 is used.
A temperature sensor that detects the temperature of 9 to 24 may be used. The mode switching means is configured to shift to the standby mode when lock or overcurrent of the motor 11 is detected by the control signal in the normal mode, or when abnormal overheating of the FETs 19 to 24 is detected. Is also good. With such a configuration, the motor 11 and the drive circuit 18
Can be protected, and power consumption when an abnormal state occurs can be suppressed.

As the boosting circuit, a boosting chopper circuit may be formed using a coil or a transformer. When braking the motor 11 by the braking circuit 25 in the standby mode, it is not always necessary to turn on all of the FETs 19 to 21, and any one or two of the FETs 19 to 21 may be turned on. good. Further, the output terminal of the braking circuit 25 is connected to the F
The control may be similarly performed by connecting to the gates of the ETs 22 to 24. Further, any two of the FETs 19 to 24 may be turned on. However, it goes without saying that a pattern in which the upper and lower arm FETs of the same phase are simultaneously turned on is excluded. The braking circuit 25 or 68 may be provided as needed. When the capacity of the motor 11 is small, the driving power supply VBL may be supplied to the driving circuit 18 via the power supply circuit 13. The motor 11
The connection is not limited to the Δ connection, but may be a Y connection. Also,
The load is not limited to the motor 11.

[Brief description of the drawings]

FIG. 1 is a diagram showing a detailed electrical configuration of a standby circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a more detailed electrical configuration of a drive control circuit;

FIG. 3 is a diagram illustrating a detailed electrical configuration of a power supply circuit.

FIG. 4 is a functional block diagram showing the entire electrical configuration.

FIG. 5 is a diagram showing a relationship between a pulse duty ratio of a drive command signal and a rotation speed of a motor.

FIG. 6 is a diagram showing a drive command signal and a signal waveform of each part of a standby circuit.

FIG. 7 is a diagram showing only a part of a configuration example of a gate drive circuit built in a control circuit;

FIG. 8 is a diagram showing an electrical configuration of a voltage drop compensation circuit according to a second embodiment of the present invention.

FIG. 9 is a diagram showing signal waveforms at various parts of the voltage drop compensation circuit.

FIG. 10 is a view corresponding to FIG. 4, showing a third embodiment of the present invention.

FIG. 11 is a view corresponding to FIG. 4, showing a fourth embodiment of the present invention;

FIG. 12 is a view corresponding to FIG. 4, showing a fifth embodiment of the present invention.

FIG. 13 is a diagram showing another configuration example of the gate drive circuit.

FIG. 14 is a diagram corresponding to FIG. 4 showing the prior art (part 1);

FIG. 15 is a diagram corresponding to FIG. 4 showing the prior art (part 2);

[Explanation of symbols]

11 is a motor (load), 12 is a fan, 13 is a drive control circuit, 14 is a power supply circuit, 15 is a battery (main power supply), 16 is a standby circuit (mode switching means), 1
8 is a drive circuit, 19 to 24 are power MOSFETs (switching elements), 25 is a braking circuit (braking means), 27
Is a first comparator, 28 is a charge / discharge switching circuit, 29 is a charging circuit, 30 is a discharging circuit, 32 is a capacitor, 33 is a second comparator, 38 and 39 are transistors (switching elements), 41 is a voltage drop compensation circuit, 42 Is a booster circuit; 61 and 62 are standby circuits (mode switching means); 63 is a sensor (load drive state detecting means); 68 is a braking circuit (braking means); 70 is a standby circuit (mode switching means); 1 shows a circuit.

Claims (15)

[Claims] 1. A drive control circuit for controlling a drive of a load based on a predetermined drive condition, a power supply circuit for supplying a drive power to the drive control circuit, and a drive control circuit for controlling the drive of the load. A load, comprising: mode switching means for switching between a normal mode and a standby mode for reducing power consumption by controlling the supply of driving power by the power supply circuit based on a control signal. Drive control device. 2. A drive control circuit for controlling drive of a load based on a predetermined drive condition, a power supply circuit for supplying a drive power to the drive control circuit, and a drive control circuit for controlling the drive of the load. A mode switching unit that switches between a normal mode and a standby mode in which the supply of the driving power is stopped by controlling the supply of the driving power by the power supply circuit based on the control signal. Load drive control device. 3. The mode switching means includes a charge / discharge switching circuit for switching charge / discharge of a capacitor according to the level of the control signal, and switches between the normal mode and the standby mode based on a terminal voltage of the capacitor. 3. The load drive control device according to claim 1, wherein switching of the load drive is performed. 4. The control signal is a signal in which a duty ratio of a pulse signal changes according to a driving condition of the load. The mode switching means switches connection to the capacitor by the charge / discharge switching circuit. A charging circuit and a discharging circuit for charging and discharging the capacitor, wherein the charging and discharging circuit has a ratio of a charging current and a discharging current between the two for switching between the normal mode and the standby mode. 4. The load drive control device according to claim 3, wherein the duty ratio of the pulse signal corresponding to a mode switching threshold is set in advance so as to be substantially equal to the duty ratio. 5. The load drive control according to claim 4, wherein a duty ratio corresponding to the mode switching threshold is set smaller than a duty ratio corresponding to a drive start condition of the load. apparatus. 6. The control signal is a signal in which the frequency of the pulse signal changes in accordance with the driving condition of the load, and the mode switching means detects the frequency of the pulse signal and detects the frequency. 3. The load drive control device according to claim 1, wherein switching between the normal mode and the standby mode is performed in accordance with a level of a frequency. 7. The control signal is a serial signal whose level changes digitally in accordance with the driving condition of the load. The mode switching means converts the serial signal into a parallel signal, 3. The load drive control device according to claim 1, wherein switching between the normal mode and the standby mode is performed based on the data value. 8. The power supply circuit supplies the drive power based on power supplied from a main power supply, and the mode switching means refers to the main power supply voltage to supply the main power supply. The load drive control device according to any one of claims 1 to 7, wherein a transition timing between the normal mode and the standby mode is changed according to a voltage change. 9. A load driving state detecting means for detecting a driving state of the load and outputting the control signal based on the driving state, wherein the mode switching means drives the load by the control signal. The load drive control device according to any one of claims 1 to 8, wherein upon detecting that the device has shifted to the stop state, the device changes from the normal mode to the standby mode. 10. The apparatus according to claim 1, wherein said mode switching means shifts from said normal mode to said standby mode even when it is detected by said control signal that the driving of said load has become abnormal. Item 10. The load drive control device according to Item 9. 11. A control state detecting means for detecting a control state of the drive control circuit and outputting the control signal based on the control state, wherein the mode switching means controls the drive control based on the control signal. The load drive control device according to any one of claims 1 to 10, wherein when the control of the circuit is detected to be in an abnormal state, a transition is made from the normal mode to the standby mode. 12. The power supply circuit is configured to control the supply of the driving power by a plurality of switching elements, and includes a boosting circuit for performing a boosting operation of the driving power supply voltage; 12. A voltage drop compensating circuit configured to compensate for the influence of a voltage drop of the driving power supply due to the plurality of switching elements based on the boosted output. A load drive control device according to any of the above. 13. A drive control circuit comprising: a booster circuit for performing a boost operation of the drive power supply voltage supplied from the power supply circuit; and a drive power supply generated by using a boosted output of the booster circuit to the drive control circuit. The load drive control device according to any one of claims 1 to 11, further comprising a power supply circuit for supplying the power. 14. The load drive control device according to claim 13, wherein said power supply generation circuit starts operation of said booster circuit when said mode switching means shifts from said standby mode to said normal mode. . 15. The drive control circuit includes a drive circuit that is configured by a plurality of switching elements connected in a bridge and drives the load. When the drive control circuit is in a state of transition to the standby mode by the mode switching unit, 2. A braking device configured to apply a braking to the load by turning on at least one of a plurality of switching elements constituting the driving circuit. Or 1
5. The load drive control device according to any one of 4.