JP2006033411A - Detection sensor circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detection sensor circuit capable of realizing a low consumption current. <P>SOLUTION: A power supply control circuit 12 of the detection sensor circuit 4 intermittently supplies a driving current Io to a semiconductor sensor 13 on the basis of an oscillation signal P. The semiconductor sensor 13 intermittently detects stepping-on operation of a brake pedal BP in response to the intermittently supplied driving current Io. Therefore, the consumption current of the semiconductor sensor 13 can be reduced. When the semiconductor sensor 13 detects the stepping-on of the brake pedal BP, it outputs an H-level detection signal CT to a drive control circuit 5. The drive control circuit 5 lights a brake lamp 3 by turning on a switching element 2 in response to the detection signal CT. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a detection sensor circuit.

  Conventionally, vehicles are equipped with various operation members such as various switches and brake pedals, and various systems of the vehicle are controlled in accordance with the operation states. For example, in a brake lamp control device, the depression state of a brake pedal is detected by a detection sensor such as a non-contact detection element, and lighting of the brake lamp (a controlled member) is controlled based on a detection signal output from the detection sensor. The

FIG. 3 shows an example of an electric circuit of the brake lamp control device 20. As shown in FIG. 3, when the sensor 21 detects that the brake pedal BP is depressed, the sensor 21 outputs a detection signal to that effect to the drive control circuit 22. The drive control circuit 22 drives the switch element 23 based on the detection signal to switch it to an on / off state, and controls lighting of the brake lamp L. That is, when the brake pedal BP is depressed, the drive control circuit 22 turns on the switch element 23. When the switch element 23 is turned on, the brake lamp L is electrically connected to the power source Vo, and the brake lamp L is lit (Patent Document 1).
Registered Utility Model No. 2551202

  By the way, the sensor 21 of the brake lamp control device 20 is constantly supplied with a drive current from the power supply circuit E, and the operation state of the brake pedal BP is kept in a constantly detectable state. For example, in the case of the brake lamp control device 20 described above, the sensor 21 is continuously supplied with a drive current Io of about several mA.

  However, in recent automobiles, various electronic devices such as a car navigation system have been mounted, and the burden on the battery power source has been increasing. Various electronic devices are required to have low current consumption. For example, in the case of the brake lamp control device 20 described above, the drive current Io of about several mA is constantly supplied by the sensor 21.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a detection sensor circuit capable of reducing current consumption.

  According to a first aspect of the present invention, there is provided a detection sensor circuit comprising a semiconductor sensor that is supplied with drive power and performs detection operation of a detection target, and outputs a detection signal of the semiconductor sensor to a drive control circuit that controls the control target. A power supply control circuit for intermittently supplying the drive power supplied to the semiconductor sensor.

  According to a second aspect of the present invention, in the detection sensor circuit according to the first aspect of the present invention, the detection sensor circuit includes an oscillation circuit that generates an oscillation signal having a predetermined period, and the power supply control circuit is based on the oscillation signal of the oscillation circuit The driving power supplied to the semiconductor sensor is intermittently supplied.

According to a third aspect of the present invention, in the detection sensor circuit according to the first or second aspect, the power supply control circuit inputs a mode setting signal from a mode setting circuit, and based on the mode setting signal, the power supply control circuit The power supply to the semiconductor sensor is changed from intermittent power supply to constant power supply.

According to the first aspect of the present invention, since the drive power is intermittently supplied to the semiconductor sensor by the power supply control circuit, the power consumption of the semiconductor sensor can be reduced.
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the power supply control circuit intermittently supplies drive power supplied to the semiconductor sensor based on the oscillation signal of the oscillation circuit. can do.

  According to the invention described in claim 3, in addition to the effects of the invention described in claim 1 or 2, the power supply to the semiconductor sensor can be changed to an intermittent power supply and a constant power supply. Can be detected.

(First embodiment)
Hereinafter, a case where the detection sensor circuit of the present invention is embodied in an automobile brake lamp control device will be described with reference to FIGS.

FIG. 1 is an electrical configuration diagram for explaining the brake lamp control device of the present embodiment.
As shown in FIG. 1, the brake lamp control device 1 includes a switching element 2, a brake lamp 3, a detection sensor circuit 4, and a drive control circuit 5 as controlled bodies.

  The switching element 2 is a semiconductor switching element such as a MOS transistor, and is connected in series with the brake lamp 3. The switching element 2 is turned on / off based on a control signal from the drive control circuit 5. When the switching element 2 is in the ON state, the brake lamp 3 is turned on by applying the power supply Vo. On the contrary, when the switching element 2 is in the OFF state, the brake lamp 3 is turned off without being applied with the power supply Vo.

  The detection sensor circuit 4 includes an oscillation circuit 11, a power supply control circuit 12, and a semiconductor sensor 13. The oscillation circuit 11 and the power supply control circuit 12 are respectively supplied with a drive voltage obtained by converting the battery voltage VB into a predetermined voltage from the power supply circuit 14.

  The oscillation circuit 11 oscillates based on the drive voltage from the power supply circuit 14 and outputs an oscillation signal P to the power supply control circuit 12 as shown in FIG. In this embodiment, the oscillation signal P is a periodic pulse signal in which the H level and the L level are intermittently repeated with a period To, and this period To is sufficient compared with the operation in which the driver depresses the brake pedal BP. It is a short period.

  The power supply control circuit 12 receives the drive voltage from the power supply circuit 14 to generate the drive current Io, and supplies the drive current Io to the semiconductor sensor 13. The power supply control circuit 12 receives the oscillation signal P from the oscillation circuit 11 and intermittently supplies the drive current Io to the semiconductor sensor 13 based on the oscillation signal P. More specifically, the power supply control circuit 12 generates the drive current Io when the oscillation signal P is at the H level and supplies the drive current Io to the semiconductor sensor 13, and stops generating the drive current Io when the oscillation signal P is at the L level. The drive current Io is intermittently supplied to the semiconductor sensor 13.

The power supply control circuit 12 is set to either the intermittent mode or the continuous mode based on the mode setting signal Q from the mode setting circuit 15. The intermittent mode is a mode in which the drive current Io is intermittently generated based on the oscillation signal P described above. Regardless of the oscillation signal P, the continuous mode is a mode in which the drive current Io is always generated and the drive current Io is constantly supplied to the semiconductor sensor 13.

  The mode setting circuit 15 outputs an L or H level mode setting signal Q based on the vehicle speed of the automobile. In this embodiment, when the mode setting circuit 15 determines that the speed is less than 50 kilometers per hour, the mode setting circuit 15 receives the L level mode setting signal Q. It is designed to output. The mode setting circuit 15 inputs a detection signal from the vehicle speed sensor, calculates the vehicle speed at that time, and generates a mode setting signal Q. When the L level mode setting signal Q is input (when the speed is less than 50 km), the power supply control circuit 12 enters the intermittent mode and when the H level mode setting signal Q is input (the speed is 50 km). In the above case, the continuous mode is set.

  The semiconductor sensor 13 is a sensor that is provided at a position adjacent to a brake pedal BP as an object to be detected, and detects a movement (operation state) of the brake pedal BP. Light sensor). The optical sensor detects the degree of depression of the brake pedal BP by irradiating the detected object with light emitted from the light emitting element and detecting the reflected light with the light receiving element.

  The semiconductor sensor 13 is supplied with the drive current Io from the power supply control circuit 12 and is in a state where a detection operation can be performed based on the drive current Io. Therefore, when the drive current Io is not supplied, the semiconductor sensor 13 enters a resting state and enters a non-detecting state. As a result, when the power supply control circuit 12 is in the intermittent mode, the driving current Io is intermittently supplied, so that the semiconductor sensor 13 performs the detection operation intermittently with the period To. That is, it can be detected only while the drive current is supplied. Further, when the power supply control circuit 12 is in the continuous mode, the driving current Io is constantly supplied, so that the semiconductor sensor 13 is always in a detection operation. Therefore, since the drive current Io is intermittently supplied to the semiconductor sensor 13 in the intermittent mode, the current consumption of the semiconductor sensor 13 becomes very small. In addition, the supply period of the drive current Io is determined by the period To of the oscillation signal P, and is a very small period. That is, since the period during which the drive current Io is not supplied is short, detection delay or detection is missed. The operation state of the brake pedal BP can be reliably detected.

  When the brake pedal BP is depressed, the semiconductor sensor 13 outputs an H level detection signal CT, and when the brake pedal BP is released without being depressed, the semiconductor sensor 13 detects an L level. The signal CT is output. Accordingly, the semiconductor sensor 13 intermittently outputs the H-bell detection signal CT to the drive control circuit 5 when the brake pedal BP is depressed while the drive current Io is intermittently supplied. Further, when the drive current Io is being supplied for a while and the brake pedal BP is not depressed, the semiconductor sensor 13 intermittently outputs the L bell detection signal CT to the drive control circuit 5. Further, when the driving current Io is not supplied, the semiconductor sensor 13 outputs the L level detection signal CT regardless of the state of the brake pedal BP.

  The drive control circuit 5 receives the detection signal CT from the semiconductor sensor 13 and outputs a control signal for turning on / off the switching element 2 based on the detection signal CT. The drive control circuit 5 outputs a control signal for turning on the switching element 2 in response to the detection signal CT at the H level. More specifically, the drive control circuit 5 outputs a control signal for turning on the switching element 2 when the detection signal CT at the H level is intermittently input with the period To in the intermittent mode. The drive control circuit 5 outputs a control signal for turning on the switching element 2 when the detection signal CT of H level is input in the continuous mode.

Next, the operation of the brake lamp control device 1 configured as described above will be described.
Now, when the vehicle speed of the automobile is less than 50 km / h, the power supply control circuit 12 is in an intermittent mode and intermittently supplies the drive current Io to the semiconductor sensor 13 in response to the oscillation signal P from the oscillation circuit 11. The semiconductor sensor 13 intermittently detects the brake pedal BP based on the drive current Io supplied intermittently.

  When the brake pedal BP is depressed, the semiconductor sensor 13 detects the depressed state and intermittently outputs an H level detection signal CT to the drive control circuit 5. The drive control circuit 5 determines that the brake pedal BP has been depressed based on the intermittently supplied H level detection signal CT, turns on the switching element 2, and turns on the brake lamp 3.

  When the vehicle speed is 50 km / h or more, the power supply control circuit 12 is in a continuous mode, constantly generating the drive current Io and supplying it to the semiconductor sensor 13. The semiconductor sensor 13 always detects the brake pedal BP based on the constantly supplied drive current Io.

  When the brake pedal BP is depressed, the semiconductor sensor 13 detects the depressed state and outputs an H level detection signal CT to the drive control circuit 5. The drive control circuit 5 determines that the brake pedal BP has been depressed based on the detection signal CT at the H level, turns on the switching element 2, and turns on the brake lamp 3.

Next, effects of the embodiment configured as described above will be described below.
(1) According to the present embodiment, the brake lamp control device 1 intermittently supplies the drive current Io supplied to the semiconductor sensor 13 to detect the state of the brake pedal BP. Therefore, the current consumption of the semiconductor sensor 13 can be reduced.

In addition, since the supply cycle of the drive current Io, that is, the period in which the drive current Io is not supplied is set to a short period that does not interfere with the detection, there is no detection delay or detection is overlooked, and the brake pedal is surely The operation state of BP can be detected.
(2) According to this embodiment, when the vehicle speed is 50 km / h or less, the intermittent mode is set to the intermittent detection operation, and when the vehicle speed is 50 km / h or more, the continuous mode is set to the constant detection state. I made it. Therefore, the semiconductor sensor 13 can execute an accurate detection operation in accordance with the vehicle speed.

(Second Embodiment)
A second embodiment in which the detection sensor circuit of the present invention is embodied in an automobile brake lamp control device will be described below.

  The mode setting circuit 15 of the present embodiment outputs an L level mode setting signal Q when an automobile ignition switch (not shown) is off. When it is determined that the ignition switch is switched from OFF to ON, the mode switch signal is switched from the L level mode setting signal Q and the H level mode setting signal Q is output.

  Then, after the ignition switch is turned on, the power supply control circuit 12 enters a continuous mode, constantly generates the drive current Io, and supplies it to the semiconductor sensor 13. The semiconductor sensor 13 always detects the brake pedal BP based on the constantly supplied drive current Io. When the brake pedal BP is depressed, the semiconductor sensor 13 detects the depressed state and outputs an H level detection signal CT to the drive control circuit 5. The drive control circuit 5 determines that the brake pedal BP has been depressed based on the detection signal CT at the H level, turns on the switching element 2, and turns on the brake lamp 3.

  Further, when the ignition switch is off (the state before the ignition switch is turned on), the power supply control circuit 12 enters an intermittent mode, and intermittently supplies the drive current Io in response to the oscillation signal P from the oscillation circuit 11. Supply to the semiconductor sensor 13. The semiconductor sensor 13 intermittently detects the brake pedal BP based on the drive current Io supplied intermittently.

  By doing so, the brake lamp control device 1 can reduce the current consumption of the semiconductor sensor 13. In addition, the semiconductor sensor 13 can be accurately detected according to the on / off state of the ignition switch.

In addition, embodiment of invention is not limited to said each embodiment, You may implement as follows.
In the above embodiment, the power supply control circuit 12 can be set to the intermittent mode and the continuous mode according to the mode setting signal Q from the mode setting circuit 15. This may be performed by omitting the mode setting circuit 15 and always setting the power supply control circuit 12 in the intermittent mode. As a result, the current consumption can be further reduced.

  In the above embodiment, the semiconductor sensor 13 that detects the brake pedal BP is an optical sensor, but is not limited to this, and may be any semiconductor magnetic sensor, for example.

  In the oscillation signal P of the above embodiment, if the detection delay and detection are not overlooked, the period To may be changed as appropriate, or the duty ratio (H level period and L level period) may be changed as appropriate. Good.

  In the above embodiment, the detection sensor circuit of the present invention is adapted to the brake lamp control device 1, but is not limited to this, and is adapted to the detection sensor circuit used in the control device of another control system. The same effects as described above can be obtained.

  The semiconductor sensor of the detection sensor circuit may be any sensor. In short, the detection sensor circuit may be applied to a detection sensor circuit of a semiconductor sensor that is supplied with drive power and performs a detection operation.

The electric block circuit diagram of a brake lamp control apparatus. The timing chart for demonstrating operation | movement of a brake lamp control apparatus. The electric block circuit diagram of the conventional brake lamp control apparatus.

Explanation of symbols

  P ... oscillation signal, Io ... drive current, Q ... mode setting signal, CT ... detection signal, 1 ... brake lamp control device as control device, 2 ... switching, 3 ... brake lamp, 4 ... detection sensor circuit, 5 ... drive Control circuit 11... Oscillator circuit 12. Power supply control circuit 13 Semiconductor sensor 14 Power circuit 15 Mode setting circuit

Claims (3)

In a detection sensor circuit that includes a semiconductor sensor that is supplied with drive power and performs detection operation of a detection target, and outputs a detection signal of the semiconductor sensor to a drive control circuit that controls the control target.
A detection sensor circuit comprising a power supply control circuit for intermittently supplying the driving power supplied to the semiconductor sensor. The detection sensor circuit according to claim 1,
An oscillation circuit for generating an oscillation signal having a predetermined cycle is provided, and the power supply control circuit intermittently supplies drive power to be supplied to the semiconductor sensor based on the oscillation signal of the oscillation circuit. Detection sensor circuit. The detection sensor circuit according to claim 1 or 2,
The power supply control circuit receives a mode setting signal from a mode setting circuit, and changes the power supply to the semiconductor sensor from intermittent power supply to constant power supply based on the mode setting signal. A characteristic detection sensor circuit.

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