Device to prevent push button switch malfunction

Abstract

To provide an erroneous operation prevention device of a push button switch which can save standby power without relying on a CPU for erroneous operation determination of a button.SOLUTION: A switch circuit having a power activation circuit 14 between a battery 12 and the operation power source 20 and urging power supply from an operation power source 20 to a control unit 30, includes a charge / discharge circuit 16 between the power activation circuit 14 and a button switch 18. The power activation circuit 14 is configured to cause activation current to flow to the operation power source 20 when there is a potential difference equal to or greater than a prescribed value between voltage between the battery 12 and the power activation circuit 14 and voltage between the power activation circuit 14 and the button switch 18 in a case where the button switch 18 is depressed. The charge / discharge circuit 16 is configured to determine, by means of setting of the time constant of shifting from the transient state to the steady state, a time in which the activation current flows when the button switch 18 is depressed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an anti-malfunction device, and more particularly to an anti-malfunction device suitable for preventing the continuous output of an activation signal when a push button switch is erroneously pressed continuously. [Background technology]

[0002] Known means for preventing malfunction of operation buttons in electronic devices and the like include, for example, the device disclosed in Patent Document 1. The malfunction prevention device disclosed in Patent Document 1 inputs an operation signal of a specific key that locks key operation to a CPU, and counts the time that the operation signal is input to this CPU (operation time) with a timer, thereby determining whether the operation of the specific key is due to a human operation or due to a factor other than human operation (malfunction), and locks or unlocks the key, etc.

[0003] With such a malfunction prevention device, it is believed that it is possible to prevent a malfunction from releasing the key lock and pressing a normal operation key, which causes the electronic device to operate, and the associated power consumption. However, the malfunction prevention device disclosed in Patent Document 1 uses a CPU and a timer to determine the operation state of the keys. As a result, the CPU continues to consume power even when the keys are not operated. Patent Document 1 also describes a sleep mode that pauses the operation of the CPU, but since a timer is used to count the operation time of a specific key when the sleep mode is released, it is unclear what state the CPU is in when it is paused.

[0004] Such malfunction prevention devices are considered to be effective for devices in which the battery is expected to be charged in a short period of time, such as one to several days.However, in a small remote control or the like that is expected to operate for several months using a small-capacity battery such as a button cell, the operating power of the CPU itself, such as that of the malfunction prevention device disclosed in Patent Document 1, accounts for a large proportion of power consumption. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-273077 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the object of the present invention is to provide a device for preventing malfunction of a push button switch that can stop the supply of power associated with pressing a button if the button is pressed by mistake, and can reduce standby power consumption without relying on a CPU to determine whether the button has malfunctioned. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a push button switch malfunction prevention device, which is a switch circuit having a power supply start-up circuit between a battery and an operating power source that prompts the supply of power from the operating power source to a control unit, and which is provided with a charge / discharge circuit between the power supply start-up circuit and a button switch, and the power supply start-up circuit is configured to flow a start-up current to the operating power source when a potential difference of a predetermined value or more occurs between the voltage between the battery and the power supply start-up circuit and the voltage between the power supply start-up circuit and the push button switch when the button switch is pressed, and the charge / discharge circuit is configured to determine the time for which the start-up current flows when the push button switch is pressed by setting a time constant for transitioning from a transient state to a steady state.

[0008] In the push button switch malfunction prevention device having the above features, the charge / discharge circuit can be a circuit in which a resistor and a capacitor are arranged in parallel. With such features, it is possible to arbitrarily determine the time constant by setting the resistance value and the capacitance of the capacitor.

[0009] In addition, it is desirable that the power supply starting circuit in the push button switch malfunction prevention device having the above-mentioned characteristics is a PNP type transistor having a base resistor, the battery is connected to the emitter side and the charge / discharge circuit is connected to the base side, and the resistance value of the base resistor is set to be smaller than the resistance value of the resistor that constitutes the charge / discharge circuit.

[0010] Furthermore, the power supply starting circuit in the push button switch malfunction prevention device having the above-mentioned characteristics can be a FET having a gate-source resistor, the battery being connected to the source side and the charge / discharge circuit being connected to the gate side, and the resistance value of the gate-source resistor can be set to be smaller than the resistance value of the resistor that constitutes the charge / discharge circuit. Effect of the Invention

[0011] With the push button switch malfunction prevention device having the above features, even if the button is pressed, the power supply can be stopped after a certain time has passed. In addition, the device does not rely on the CPU to determine whether the button is malfunctioning. This makes it possible to reduce standby power consumption compared to conventional devices. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a schematic configuration of a small remote control to which a push button switch malfunction prevention device according to an embodiment is applied; [Diagram 2] 1A to 1C are diagrams for explaining the configuration of a push button switch malfunction prevention device according to a first embodiment. [Diagram 3] 11A and 11B are diagrams for explaining the configuration of a push button switch malfunction prevention device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a push button switch malfunction prevention device according to the present invention will be described in detail with reference to the drawings. [composition] The push button switch malfunction prevention device according to this embodiment (hereinafter simply referred to as malfunction prevention device 10) is applied to a portable small remote control or the like, and the push button switch may be, for example, an operation button such as a button for locking / opening a vehicle key, a button for opening and closing a door, or a button for starting an engine. FIG. 1 is a schematic diagram showing the configuration of a small remote control 50 to which the malfunction prevention device 10 according to the embodiment is applied. As shown in FIG. 1, the small remote control 50 has at least a battery 12, an operating power source 20, a power supply starting circuit 14, a button switch 18, a charge / discharge circuit 16, a control unit 30, and a power supply holding circuit 40.

[0014] The battery 12 may be a primary battery such as a button battery or a rechargeable secondary battery, and is an element that supplies power resulting from button operation to the control unit 30, operating power source 20, etc. via the power supply start-up circuit 14 when a button switch 18, which will be described in detail later, is pressed.

[0015] The operating power source 20 is an element for supplying the power required to output operation signals for various operations to a control unit 30 (to be described in detail later) and the like, and outputs the power based on the power supplied from the battery 12.

[0016] The power supply startup circuit 14 is a startup circuit for urging the power supply from the operating power supply 20 to the control unit 30. When the current from the battery 12 flows through the path on the button switch 18 side, the power supply to the operating power supply 20 side is prompted, and the operating power supply 20 is started up.

[0017] The button switch 18 is a button for executing various functions using the compact remote control 50. Although the example shown in Fig. 1 shows a single button switch 18, a plurality of button switches 18 may be provided. When a plurality of button switches 18 are provided, it is desirable to provide them so as to be connected in parallel to the secondary side of the charge / discharge circuit 16, the details of which will be described later. This is because such a configuration makes it possible to secure the functions provided by the charge / discharge circuit 16 while maintaining a single charge / discharge circuit 16.

[0018] The charge / discharge circuit 16 is an element for controlling the current supplied to the path on the button switch 18 side via the power supply starting circuit 14. When the charge / discharge circuit 16 is in a charging state (transient state), a potential difference occurs between the path of the battery 12-power supply starting circuit 14 and the path of the charge / discharge circuit 16-power supply starting circuit 14, so that power is supplied to the charge / discharge circuit 16 side, i.e., the path on the button switch 18 side. On the other hand, when the charge / discharge circuit 16 reaches a charging completion state (steady state), there is almost no potential difference between the above two paths, and the power supply to the path on the button switch 18 side is stopped (becomes extremely small). Therefore, even if the button switch 18 is continuously pressed, the power supply to the path on the button switch 18 side is stopped, making it possible to reduce power consumption.

[0019] The control unit 30 is an element such as a microcomputer that performs decision processing for executing various functions, and outputs control signals, etc. The control unit 30 receives power from the button switch 18 side path and from the operating power source 20, and uses this as an input signal to decide on the required control and output control signals, etc.

[0020] The power supply holding circuit 40 is an element for preventing the power supply to the operating power source 20 from being stopped by the action of the charge / discharge circuit 16 while the control unit 30 is operating. The power supply holding circuit 40 lowers the potential of the path on the charge / discharge circuit 16 side in the power supply starting circuit 14 based on a control signal from the control unit 30, and performs an action equivalent to a pseudo power supply to the path on the charge / discharge circuit 16 side. This allows power to be supplied to the operating power source 20 via the power supply starting circuit 14.

[0021] In the compact remote control 50 having such a basic configuration, the malfunction prevention device 10 according to the present invention is composed of a battery 12, a power supply starting circuit 14, a charge / discharge circuit 16, and a button switch 18. A specific embodiment of the malfunction prevention device 10 composed of these elements will be described below.

[0022] [First embodiment] 2, a PNP-type transistor is used for the power supply starting circuit 14, and the charge / discharge circuit 16 is configured by connecting a resistor 16a and a capacitor 16b in parallel. The power supply starting circuit 14, which is configured by a transistor, is provided with a base resistor 14a and a base-emitter resistor 14b.

[0023] Here, the resistance value of the base resistor 14a is configured to be sufficiently smaller than the resistance value of the resistor 16a constituting the charge / discharge circuit 16 (about 1 / 10 in the example shown below). With such a configuration, it is possible to balance the charging and discharging in the charge / discharge circuit 16, and to reduce the time constant until the charge / discharge circuit 16 transitions from a transient state to a steady state. The capacitance of the capacitor 16b constituting the charge / discharge circuit 16 may be determined so as to obtain a desired time constant, taking into consideration the resistance value of the resistor (base resistor 14a) associated with the transistor and the resistance value of the resistor 16a constituting the charge / discharge circuit 16.

[0024] As an example, if the resistance value of base resistor 14a is 100 kΩ and the resistance value of resistor 16a that constitutes charge / discharge circuit 16 is 1 MΩ, then by setting the capacitance of capacitor 16b to 1 μF, the charge time constant will be 0.1 seconds and the discharge time constant will be 1 second (time constant T=CR: C=capacitor capacitance, R=resistance value).

[0025] [Effect] When the malfunction prevention device 10 is configured in this way, the following action is achieved by pressing the button switch 18. First, when the button switch 18 is pressed, a current flows from the emitter side to the base side of the transistor that constitutes the power supply starting circuit 14, and the current is supplied to the charge / discharge circuit 16. At this time, the current from the battery 12 also flows to the operating power supply 20 located on the collector side.

[0026] When the button switch 18 is kept pressed, the capacitor 16b constituting the charge / discharge circuit 16 is charged, and the potential difference between the emitter circuit and the base circuit disappears (becomes smaller), and the current flow from the emitter to the base stops. This also stops the power supply from the collector side.

[0027] [effect] As a result, even if the button switch 18 is kept pressed, the current flowing to the circuits on the receiving side, such as the control unit 30, is cut off, making it possible to reduce power consumption. Also, the cutting of the current to the circuits on the receiving side, such as the control unit 30, is based on the change in potential between the charge / discharge circuit 16 and the power supply start-up circuit 14 and does not involve control by the CPU, etc., so the power consumed by the CPU, etc. can be reduced.

[0028] [Second embodiment] Next, a configuration in which a FET is used in the power supply starting circuit 14 will be described with reference to Fig. 3. When the power supply starting circuit 14 is configured with a FET, the battery 12 is connected to the source side, the button switch 18 to the gate side, and the operating power supply 20 to the drain side. In the example shown in Fig. 2, a gate-source resistor 14c is also provided.

[0029] The charge / discharge circuit 16 may be configured with a resistor 16a and a capacitor 16b, similar to the case where a transistor is used in the power supply starting circuit 14 (the form shown in FIG. 2). Here, the resistor 16a is determined to have a resistance value that is sufficiently larger (for example, 10 times larger) than the resistance value of the gate-source resistor 14c in the FET that constitutes the power supply starting circuit 14.

[0030] [Actions and Effects] Even if the malfunction prevention device 10 is configured in this manner, as with the malfunction prevention device of the above embodiment, the current flowing to the control unit 30 is cut off even if the button switch 18 is continuously pressed, thereby making it possible to reduce power consumption. [Industrial Applicability]

[0031] In the above embodiment, a vehicle operation remote control was used as an example of a small remote control 50 to which the malfunction prevention device 10 is applied, but the push button switch malfunction prevention device 10 of this embodiment can also be applied to remote controls used for other purposes. [Explanation of symbols]

[0032] 10.... Malfunction prevention device, 12.... Battery, 14.... Power supply start circuit, 14a.... Base resistor, 14c.... Gate-source resistor, 16.... Charge / discharge circuit, 16a.... Resistor, 16b.... Capacitor, 18.... Button switch, 20.... Operating power supply, 30.... Control unit, 40.... Power supply maintenance circuit, 50.... Small remote control.

Claims

1. A switch circuit having a power supply starting circuit between a battery and an operating power supply, the power supply starting circuit urging a supply of power from the operating power supply to a control unit, A charge / discharge circuit is provided between the power supply starting circuit and the button switch, the power supply starting circuit is configured to supply a starting current to the operating power supply when a potential difference of a predetermined value or more is generated between a voltage between the battery and the power supply starting circuit and a voltage between the power supply starting circuit and the button switch when the button switch is pressed; A device for preventing malfunction of a push button switch, characterized in that the charge / discharge circuit is configured to determine the time for which the startup current flows when the button switch is pressed by setting a time constant for transitioning from a transient state to a steady state.

2. 2. The device for preventing malfunction of a push button switch according to claim 1, wherein the charge / discharge circuit is a circuit in which a resistor and a capacitor are arranged in parallel.

3. the power supply starting circuit is a PNP transistor having a base resistor, the battery is connected to an emitter side, and the charge / discharge circuit is connected to a base side; 3. The device for preventing malfunction of a push button switch according to claim 2, wherein a resistance value of the base resistor is set to be smaller than a resistance value of the resistor constituting the charge / discharge circuit.

4. the power supply starting circuit is an FET having a gate-source resistor, the source side of which is connected to the battery, and the gate side of which is connected to the charge / discharge circuit; 3. The device for preventing malfunction of a push button switch according to claim 2, wherein the resistance value of the gate-source resistor is set to be smaller than the resistance value of the resistor constituting the charge / discharge circuit.

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