JPH0444065B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a switch signal input device for inputting the open/closed state of the contacts of a manually operated switch.
For example, it can be applied to vehicle door functional devices such as electric vehicle door lock devices and electric window opening/closing devices.

[Conventional technology]

When controlling the operation of a device according to the open/closed states of the contacts of a switch, it is necessary to reduce the current flowing through the contacts of the switch in order to keep the power consumption of the switch low. However, on the other hand, when the current flowing through the contacts is reduced, there is a problem in that it becomes difficult to accurately detect whether the contacts are open or closed.

For example, vehicle door function devices, especially electric locking devices, generally operate by receiving power directly from the battery, so they remain in operation even when there are no occupants in the vehicle and the ignition switch is turned off. Consumes electricity. Therefore, in order to suppress battery consumption, it is necessary to suppress the power consumption for detecting the opening and closing of the switch. However, on the other hand, the switch of the electric lock device is installed integrally with the vehicle door in order to respond to the activation of the key cylinder operated from outside the vehicle. Due to this, there were cases where the building was exposed to water such as rainwater. When exposed to water, a weak current may flow even though the switch contacts are open, making it difficult to distinguish from when the switch contacts are closed. In addition, if the resistance value increases due to deterioration of the switch contacts, sufficient current will no longer flow even when the switch contacts are closed, making it difficult to distinguish from when the switch contacts are open. become. In this way, a device that inputs the open/closed state of a switch's contacts has the trade-off of requiring a large current to flow through the contacts in order to reliably detect whether the switch's contacts are open or closed while reducing power consumption. There was a request to do so.

Conventionally, for example, the technique disclosed in Japanese Unexamined Patent Publication No. 124992/1983 has been known, but with this conventional technique, noise is generated when voltage is applied between the contacts of the switch, and the open/closed state of the switch is There was a possibility that it could not be detected accurately.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned problems of the conventional technology, allows a sufficiently large current to flow between the switch contacts, reduces the power consumption of the switch signal input device, and accurately detects the open/closed state of the switch contacts. It is an object of the present invention to provide a switch signal input device that can perform the following functions.

[Means for solving problems]

In order to achieve the above object, the present invention provides a switch signal input device for inputting the open/closed state of a contact of a manually operated switch, which comprises a pulse signal generating means for periodically generating a pulse signal, and a pulse signal generating means for periodically generating a pulse signal; a switching circuit that periodically applies a DC voltage between the contacts of the switch in response to a signal; and a switching circuit that periodically applies a DC voltage between the contacts of the switch; a timing means for obtaining a determination timing with a delay; and a timing means for determining the open/closed state of the contacts based on the presence or absence of energization between the contacts of the switch at the determination timing obtained by the timing means, and generating a signal indicating the open/closed state of the contacts; A technical means is adopted in which the method includes a determination means that holds the signal until the next determination timing.

[Effect]

According to the configuration of the present invention described above, a direct current is periodically applied between the contacts of the switch. and,
During the application of the DC voltage, at a determination timing that is delayed by a predetermined time from the application of the voltage,
The presence or absence of current between the contacts of the switch to which voltage is applied is detected, and the open/closed state of these contacts is determined and held until the next determination timing. Therefore, transient current immediately after voltage application is not detected.
When the current flowing through the switch contacts becomes stable due to voltage application, it is determined whether the switch contacts are open or closed.

〔Example〕

In the accompanying drawings, reference numerals 1A and 1B indicate manual switches integrally provided with the vehicle door, which in this embodiment are a lock command switch and an unlock command switch of an electric door lock device. These switches 1A and 1B are grounded at one end, and when a switch current is supplied, a potential corresponding to the opening or closing of the switch is generated at the other terminals.

This potential is applied to the switch signal input circuit 2, and in this circuit 2, the open/closed state of each switch is determined. An electrical signal representing the determination result is transmitted to the logic circuit 3.

Logic circuit 3 when each switch is closed,
Two timer circuits 3 each generating a time signal
1 and 32, and each time signal is given as a signal to make each transistor 41 and 42 of the drive circuit 4 conductive. In the drive circuit 4, when one of the transistors 41 energizes the relay 43, a current flows in a predetermined direction to the door lock operating motor 5 through the closed contacts, thereby moving the door lock member (not shown) to the locked position. When the door lock member is moved and the other transistor 42 energizes the relay 44, a current flows in the opposite direction to the motor 5 and moves the door lock member to the unlocked position.

The switch signal input circuit 2 includes an oscillation circuit 6 that generates a clock signal of a constant frequency, and an intermittent pulse signal that receives the clock signal and becomes high level for a determined period _T1 and a determined time _T2 . counter circuit 7. Counter circuit 7
The intermittent pulse signal is applied via the buffer 9 to a semiconductor switching circuit consisting of two transistors 10 and 11, and when the intermittent pulse signal is at a high level, the transistor 12 becomes conductive, thereby causing the pull-up resistors 12 and 13 to become conductive. A switch current is supplied to each switch 1A, 1B through the switch.

Here, the magnitude of the switch current can be set by pull-up resistors 12 and 13. When the duty ratio T ₂ /T ₁ of the intermittent pulse signal generated by the counter circuit 7 is set to 1/80, power consumption can be reduced compared to a constantly energized type even if the magnitude of the switch current is increased several tens of times.

The intermittent pulse signal generated by the counter circuit 7 is delayed by the delay circuit 14, and a timing pulse signal that becomes high level a little after the switch current starts being supplied is sent to the two D-type flip-flop circuits 15A and 15B. Give. When flip-flop circuits 15A and 15B receive the timing pulse signal, they turn on switches 1A and 1B, respectively.
The internal state is determined according to the potential of the terminal.

If switch 1A (or 1B) is open, flip-flop circuits 15A and 15
The input terminal D of B becomes high level when receiving the intermittent pulse signal, and when the timing pulse signal from the delay circuit 14 is applied, a signal that becomes high level is generated at the output terminal Q, and the state is changed to the next one. Hold until a timing pulse signal is applied.

On the other hand, when the switches 1A and 1B are closed, the input terminals D of the flip-flop circuits 15A and 15B become low level, and in synchronization with the timing pulse signal from the delay circuit 14, a low level signal is generated and held at the output terminal Q. .

In this way, the flip-flop circuits 15A, 15
B is the period of the intermittent pulse signal and switches 1A, 1
A determination is made in state B, a signal level corresponding to the determination result is generated at the output terminal Q, and this is applied to the subsequent logic circuit 3.

Note that part of the circuit configuration described above can also be replaced by processing on software of a microcomputer. For example, the functions of the counter circuit 7 and the delay circuit 14 can be implemented by timer interrupt processing in the control program, and the determination functions of the flip-flop circuits 15A and 15B can be performed by checking the level of the signal applied to the input port. It can be implemented.

Further, the present invention can also be applied to manual switches and detection switches having meanings other than those described above.

〔Effect of the invention〕

According to the present invention described above, a DC voltage is periodically applied between the contacts of the switch, and whether or not the contacts of the switch are energized is detected at a determination timing delayed by a predetermined time from the application of this voltage. Even if the current flowing between the contacts of the switch is increased, the power consumption does not increase, and the opening/closing of the switch contacts can be accurately detected with small power consumption. In particular, since the determination timing is obtained after a predetermined time delay from the application of DC voltage, there is no need to detect transient currents caused by periodic application of DC voltage, and this also allows large currents to flow.
Accurate and stable open/close detection of switch contacts can be performed.

[Brief explanation of drawings]

The accompanying drawings are electrical wiring diagrams showing one embodiment of the present invention. 1A, 1B... switch, 2... switch signal input circuit, 3, 4, 5... logic circuit, drive circuit, and motor forming a vehicle door function device, 6, 7... oscillation circuit forming pulse signal generating means. counter circuit,
10, 11, 12, 13...transistors 10, 11 and resistors 12, 1 forming a switching circuit
3, 14...Delay circuit serving as timing means, 1
5A, 15B...Flip-flop circuits serving as determination means.

Claims (1)

[Scope of Claims] 1. A switch signal input device for inputting the open/closed state of a contact of a manually operated switch, which comprises: a pulse signal generating means that periodically generates a pulse signal; and a pulse signal generating means that responds to the pulse signal. a switching circuit that periodically applies a DC voltage between the contacts of the switch; and a switching circuit that periodically applies a DC voltage between the contacts of the switch; and a timing means for determining the open/closed state of the contacts of the switch based on the presence or absence of energization at the determination timing obtained by the timing means, generating a signal indicating whether the contacts are open or closed, and using the signal for the next determination. A switch signal input device comprising: determination means for holding until timing.