JPH0558250A - Wiper controller - Google Patents

Abstract

PURPOSE:To provide a wiper controller for the control according to the operation mode in which a wiper motor is designated, by using a semiconductor circuit element. CONSTITUTION:A wiper controller is equipped with a wiper motor 12 having a high speed operation terminal and a low speed operation terminal and a wiper switch circuit 17, and if HIGH is set in this switch circuit 17, a +B electric power source is connected with the high speed operation terminal of the motor 12 through a +2 terminal. When INT mode is selected, an FET driving circuit 20 operates the first FET 21 by the instruction supplied from the switch circuit 17, and the wiper motor 12 is controlled according to the INT mode. In this case, if HIGH mode is set, the electric current due to the reverse electromotive force outputted to the low speed operation terminal of the motor 12 flows in the first FET 21, and the diodes D1 and D2 for suppressing the counterflow are connected in the circuit of the first FET 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiper control device in which a wiper motor is controlled by a semiconductor switch element.

[0002]

2. Description of the Related Art In order to control a wiper for an automobile, a relay circuit is generally used to control a power supply to a wiper motor. However, when a relay is used, not only relay noise is generated during intermittent operation, but also the motor current is opened and closed by a mechanical contact, so the durability of this contact portion becomes a problem.

In order to deal with such a problem, a wiper control device constructed by using a semiconductor switch element as disclosed in, for example, Japanese Patent Laid-Open No. 60-56655 has been considered. In this control device, a power supply is connected to the high speed operation terminal or the low speed operation terminal of the wiper motor in the high speed scanning mode (HIGH mode) and the low speed scanning mode (LOW mode) by the wiper switch circuit, and the The wiper operation is performed in the LOW mode.

Further, in the intermittent scanning (INT) mode and the OFF (OFF) mode, a command is given to the semiconductor drive circuit section, the semiconductor switch element is turned on / off by the command from this drive circuit, and the semiconductor switch element is supplied to the wiper motor. The power is controlled to be turned on and off, and a predetermined wiper operation is executed.

In such a configuration, the + B power source is connected to the low speed operation terminal of the wiper motor in the LOW mode state, and the + B power source is connected to the low speed operation terminal of the wiper motor in the INT mode via the semiconductor switch element. Connected. That is, the low-speed operation terminal of the wiper motor is connected and set to the semiconductor switch element.

Further, in the HIGH mode, the + B power source is connected to the high speed operation terminal of the wiper motor, and when the wiper motor is driven in such a HIGH mode, electromotive force is generated in the wiper motor. Then, reverse current is output to the low speed operation terminal. Then, this reverse current comes to flow in the semiconductor switch element as a reverse direction current, which may damage the semiconductor switch element.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and particularly when a wiper motor is controlled by using a semiconductor circuit, the current for driving the wiper motor is turned on / off. It is an object of the present invention to provide a wiper control device that surely prevents a reverse current from being supplied to a semiconductor switch element to be controlled, and executes highly reliable wiper control.

[0008]

A wiper control device according to the present invention is a wiper motor in which a high speed operation terminal and a high speed operation terminal are set, and a wiper in which a high speed scanning mode, a low speed scanning mode, an intermittent scanning mode or the like is selected. A semiconductor device is provided with a switching device, and the semiconductor switching device is controlled by a driving means to which a command is supplied from the switching device at least in the intermittent scanning mode, and the semiconductor switching device causes the wiper motor to operate at low speed intermittently. Then, at least in the high-speed scanning mode, circuit means for preventing a reverse current generated at the low-speed operation terminal of the wiper motor from flowing backward to the semiconductor switch element is set.

[0009]

In the wiper control device constructed as described above, in the high speed scanning mode, the + B power source is connected to the high speed operation terminal portion of the wiper motor, and the low speed operation terminal of the wiper motor is, for example, in the intermittent scanning mode. + B via semiconductor switch circuit
The power supply is designed to be connected. Therefore, in the high-speed scanning mode setting state, the + B power source is connected to the high-speed operation terminal of the wiper motor, and this motor is rotating at high speed. Therefore, a reverse current is generated at the low-speed operation terminal by the electromotive force. Then, the reverse current is supplied to the semiconductor switch element. However, since the circuit means for preventing the reverse current from flowing through the semiconductor switch element is set, the semiconductor switch element is reliably protected from damage and the reliability of the wiper control device is improved. It

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the circuit configuration of the wiper motor circuit 11. The wiper motor circuit 11 includes a wiper motor 12 having a low speed operation terminal connected to terminal +1 and a high speed operation terminal connected to terminal +2. Is the ground terminal E
Connected to. The wiper motor 12 is equipped with a cam disk (not shown) that is coaxially rotated,
Switch 13 when the wiper completes one scan
To switch.

The switch 13 is normally connected to the terminal a as shown in the figure and connects the terminal S to the ground circuit, but is connected to the terminal b when switched by the cam disk. The + B power supply is connected to the terminal S.

+ B by the power source 14 by the vehicle battery
The power supply is set, and this power supply 14 is connected to the + B terminal of the wiper motor circuit 11 via the ignition switch 15.
Further, it is connected to the + B terminal of the control device 16.

The wiper control command is generated in the wiper switch circuit 17. This wiper switch circuit
Reference numeral 17 is, for example, controlled by a wiper operator in the driver's seat. When the wiper is stopped (OFF), the +1 terminal and the S terminal are connected, and in the intermittent (INT) scanning mode, the +1 terminal and the S terminal are connected. Connect the terminal and the ground terminal E. Furthermore, in the low speed scanning (LOW) mode,
One terminal is connected and the +2 terminal and the + B terminal are connected in the high speed scanning (HIGH) mode. Then, when the washer mode (W) is selected, power is supplied to the washer motor 18.

The +2 terminal of the wiper switch circuit 17 is connected to the terminal +2 of the wiper motor circuit 11, and + B
The terminal should be connected to the power supply 14, and +1, C
The outputs from the 1 and W terminals are respectively supplied to the control device 16.

The controller 16 comprises a FET drive circuit 20 to which the signals +1, C1 and W from the wiper switch circuit 17 are supplied. The drive circuit 20 is also supplied with a signal from the terminal S.

The drive circuit 20 includes first and second field effect transistors (F) which form a semiconductor switch element.
ET) 21 and 22. These FETs 21 and 22 are provided with Zener diodes Z1 and Z2, respectively, which are simultaneously produced at the time of manufacture. And the first
FET21 is connected to the +1 terminal of the wiper motor circuit 11 via the + B terminal and the terminal M, and the second FET22 is connected to the terminal M.
Connected to the ground terminal E.

Although not shown in detail here, the FET drive circuit 20 operates the first FET 21 by the +1 signal from the switch circuit 17 when the LO mode is selected by the wiper switch circuit 17, Power is supplied to the low speed operation terminal of the wiper motor 12.

Further, when the INT mode is selected by the switch circuit 17, the first F is in accordance with the command of the C1 terminal.
The ET21 is turned on to operate the wiper motor 12 at a low speed. When the selector switch 13 is switched and a signal is output to the S terminal, the first FET21 is turned off and the second FET22 is turned on. .. This second FET 22
Grounds the low speed operation terminal of the wiper motor 12 via the M terminal, grounds the electric power generated when the motor 12 is rotated by inertia, and executes dynamic braking. Then, the intermittent scanning mode is set by repeating such an operation.

In such a wiper control device, when the high speed scanning (HIGH) mode is selected in the wiper switch circuit 17, the +2 terminal of the wiper motor circuit 11 is connected to the + B power source, and the broken line arrow in the figure. A current as shown by (1) flows through the high speed operation terminal of the wiper motor 12 to drive the wiper at high speed. At the same time, a counter electromotive force is generated in the coil inside the wiper motor 12,
The reverse current is output via the low-speed operation terminal of the motor 12 as shown by the solid arrow.

The counter electromotive voltage in the motor 12 is as high as 60 V or more, and this counter current is supplied from the terminal +1 to the terminal M of the control device 16 and is attached to the first FET 21. It will flow through the diode Z1. This current not only destroys the first FET 21, but also goes in the opposite direction to the current path in the HIGH mode, and normal operation in the HIGH mode will not be performed.

Therefore, in the device shown in this embodiment, the diodes D1 and D2 for blocking the reverse current are connected in series to the source and drain of the first FET 21, respectively. These diodes D1 and D2
May be only one of them.

It is also conceivable to connect a diode for blocking a reverse current in series with the terminal M of the control device 16, but this will cut off the braking current flowing through the second FET 21, and the wiper motor 12 will be turned off. It becomes difficult to perform stop control at the normal position.

In the wiper control device shown in this embodiment, in the wiper motor drive part of the control device 16,
Particularly, when a semiconductor switch element such as a power MOSFET is used, it is intended to prevent a reverse current due to a reverse voltage generated when the wiper motor 12 operates in the HIGH mode. Therefore, the reverse current blocking means can be configured in a portion other than the control device 16.

For example, the wiper switch circuit 17 is constructed as shown in FIG. That is, in the OFF mode, the INT mode, and the LOW mode, the S terminal and the +1 terminal are all connected in the respective modes.
Only in the HIGH mode, the + B terminal is connected to the +2 terminal so that the + B power source is connected to the high speed operation terminal of the wiper motor 12 when the HIGH mode is selected.

When the wiper switch circuit 17 is constructed as described above, the electromotive voltage generated in the wiper motor 12 during the operation in the HIGH mode is applied to the +1 terminal of the wiper switch circuit 17. However, since the wiper switch circuit 17 is set to the HIGH mode, the +1 terminal is in the open state, and the reverse current is not supplied to the M terminal of the control device 16.

When the wiper switch circuit 17 is set to the OFF mode, the INT mode, and the LOW mode, the output from the M terminal of the control device 16 is the switch circuit 17.
Wiper motor circuit 11 via S terminal and +1 terminal of
It will be supplied to the +1 terminal and will operate normally.

Here, in OFF, INT, and LOW, the S terminal and the +1 terminal are all connected in their respective modes. Therefore, this switch mode identification cannot be performed in the drive circuit 20 in the control device 16. Therefore, in this embodiment, the 2S terminal is added to ensure that the mode is identified.

In this case, of course, the 2S terminal input to the control device 16 is increased, and the mode can be discriminated by the combination of the signals of the 2S terminal and the C1 terminal. The identification table is shown. This identification combination can be set in any combination as long as OFF, INT, LOW, and HIGH can be identified, and it is not necessary to pay particular attention to the 2S terminal and the C1 terminal.

The means for blocking the reverse current in the control device 16 is not limited to the diodes D1 and D2 shown in FIG. FIG. 3 shows an embodiment constituted by mechanical contacts, and a relay circuit 30 is added in place of the diodes D1 and D2 to the embodiment shown in FIG.

The relay circuit 30 is connected between the first FET 21 and the terminal + B, and is a wiper switch circuit.
It includes a transistor 31 whose operation is controlled by a signal from the +2 terminal of 17 when the HIGH mode is set.

A relay coil 32 is connected to the collector circuit of the transistor 31, and when the transistor 31 is turned on, that is, when the HIGH mode is set, an exciting current flows through the relay coil 32 and the relay contact 321 opens. Be done. This relay contact 321 is connected to the terminal M in series, and is only connected to the first F terminal in the HIGH mode.
The reverse current circuit flowing through the ET21 is cut off to protect the FET21 from destruction.

The wiper switch circuit 17 is in the OFF mode,
In INT mode and LOW mode, no voltage is applied to the +2 terminal, so
31 is not turned on and the exciting current does not flow in the relay coil 32. Therefore, the relay contact 321 is maintained in the ON state, and when the first FET 21 is activated, the wiper motor 12 is provided with an appropriate output.

In this embodiment, the relay contact is shown in the normally closed state, and the drive circuit of this relay circuit is shown to use the transistor 31, but it is supplied to the first FET 21 in the HIGH mode state. Any circuit element can be applied as long as it cuts off the reverse current circuit.

[0034]

As described above, according to the wiper control device of the present invention, when the semiconductor circuit is used, the reverse current flowing through the semiconductor switch element for driving and controlling the wiper motor is surely blocked, The semiconductor switch element is reliably protected from reverse current. Therefore, any of the wiper operation modes can be properly set, and reliability can be easily ensured.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram for explaining a wiper control device according to an embodiment of the present invention.

FIG. 2A is a diagram showing a wiper switch circuit according to a second embodiment of the present invention, and FIG. 2B is a diagram showing a discriminating state of its operation.

FIG. 3 is a circuit diagram for explaining a third embodiment of the present invention.

[Explanation of symbols]

11 ... Wiper motor circuit, 12 ... Wiper motor, 14 ... Power supply, 15 ... Ignition switch, 16 ... Control device, 17 ...
Whiper switch circuit, 20 ... FET drive circuit, 21, 22 ...
1st and 2nd FET, 30 ... Relay circuit.

Claims (1)

[Claims] 1. A wiper motor having a high speed operation terminal and a low speed operation terminal, in which high speed and low speed operations are selectively set, and a wiper switch for connecting a power source to the high speed operation terminal of the wiper motor in a high speed scanning mode of the wiper. A device, drive means to which a command signal is given at least in the intermittent scanning mode setting state of the wiper switch device, and on / off control by a command from the drive means,
A first semiconductor switching device that supplies power to a low-speed operation terminal of the wiper motor, and ON control is performed when the first semiconductor switching device is in an OFF state, and generated power generated by the wiper motor is grounded to perform braking control. A second semiconductor switching device, and circuit means for preventing a reverse current generated at a low speed operation terminal of the wiper motor from flowing back to the first semiconductor switching device in a high speed scanning mode state of the wiper switching device. And a wiper control device.