JP4988192B2 - Lighting device and lighting head used in the lighting device - Google Patents

Description

  The present invention relates to an illumination device for lighting an illumination head including an illumination circuit to which a light emitting diode is connected, in a replaceable manner with a power supply device, and the illumination head.

  When an illumination head with a large number of light emitting diodes is connected to a power supply device and used, the power supply device turns on the lighting head by supplying an appropriate current that allows the rated current to flow through each light emitting diode. Power supply power is set as follows.

Recently, even when an illumination head capable of individually lighting individual light emitting diodes is connected to the power supply device, there is a power supply device that can control the supply current according to the number of lighting so that the rated current can be supplied to each light emitting diode. Proposed.
Japanese Patent Laid-Open No. 2000-6466

  However, this type of power supply adjusts the current according to the number of light-emitting diodes when a specific lighting head is connected. When used as a power supply for lighting heads with different specifications, The current cannot be adjusted accordingly.

Therefore, recently, as shown in FIG. 5, different types of illumination heads 52... Can be attached to and detached from the power supply device 51 via a connector 53, and the illumination head 52 includes an illumination circuit 55 including a light emitting diode 54. In parallel, an identification circuit 57 having an identification resistor 56 having a higher resistance value than that of the light emitting diode 54 is formed, and the resistance value of the identification resistor 56 is measured by applying an identification voltage lower than the lighting lower limit voltage of the light emitting diode 54. Based on this, a lighting device 50 is proposed in which the type of the lighting head 52 is discriminated and a current corresponding to the type of the lighting head 52 is supplied from the power supply circuit 58 of the power supply device 51 at the operating voltage. Yes.
According to this, since the kind of lighting heads 52 connected to the power supply device 51 can be determined, it is possible to light up with appropriate brightness according to the specification of each lighting head 52.
JP2004-158840

However, when the lighting heads 52 are installed away from the power supply device 51, it is necessary to connect the power supply devices 51 and the lighting heads 52 with a long cable, and the internal resistance of the cable cannot be ignored. When the resistance value is detected, an error occurs, and as a result, the lighting heads 52 may be erroneously discriminated and the rated current corresponding to the type cannot be supplied.
Further, since the identification resistor 56 is connected in parallel with the light emitting diode 54, a current also flows through the identification resistor 56 when the light emitting diode 54 is turned on, and the current values thereof are the respective circuits of the illumination circuit 55 and the identification circuit 57. Since it depends on the resistance and the voltage applied from the power supply device 51, it is difficult to specify.
For this reason, it is difficult to accurately control the drive current of the light emitting diode 54 and the light quantity is likely to vary. When the subject illuminated by the illumination device 50 is imaged and image-processed, the processed image data is converted into the processed image data. There was a problem that the effect of the difference in the amount of light remained.

  Therefore, the present invention does not erroneously identify the illumination head even when the illumination head is installed away from the power supply device, and can maintain the light amount constant by accurately controlling the drive current of the light emitting diode. Doing this is a technical challenge.

In order to solve this problem, the present invention provides an identification circuit that includes an illumination circuit including one or more light emitting diodes and an identification head that includes an identification element that identifies a rated current of the illumination circuit. A lighting device that supplies a rated current from a power supply device in accordance with an identification signal output from the light emitting diode of an illumination head,
In the lighting head, a constant current element that outputs an identification current having a predetermined current value set in advance according to a rated current as an identification element is connected in series with the light emitting diode,
The power supply device includes a rated current setting circuit that sets a rated current based on a current value of an identification signal output from the constant current element, and a current that flows through a lighting circuit to a rated current set by the rated current setting circuit. A matching current control circuit is formed,
The bypass circuit that bypasses the constant current element is provided with a timer switch that is conductive when a preset identification current measurement time has elapsed after the start of energization of the illumination circuit.

According to the present invention, the identification circuit branched from the illumination circuit of the illumination head is provided with a constant current element that outputs an identification current having a predetermined current value set in advance according to the rated current. When a predetermined voltage is applied from the power supply device through the circuit, the voltage is also applied to the identification circuit, and an identification current having a predetermined current value set in advance according to the rated current of the lighting head is output from the constant current element. .
Since the current value of the identification current output from the constant current element is always constant as long as it is within the predetermined operating voltage range, even if the cable connecting the lighting head and the power supply device has an internal resistance, the current of the identification current The value is kept constant.

The current value of the identification current is detected by the rated current setting circuit provided in the power supply device, the rated current of the lighting head is set, and the current control circuit so that the current flowing through the lighting circuit matches the rated current Current control.
In this way, since a constant current element is used instead of an identification resistor as an identification element, even when the internal resistance of the cable cannot be ignored as when the lighting head is installed away from the power supply device, The constant current element outputs an identification signal having a current value corresponding to the rated current. Therefore, the rated current of the lighting head can be accurately set, and the drive current is controlled to match the rated current.

  In this example, when the illumination head is installed away from the power supply device, the illumination head is not misidentified, and the driving current of the light emitting diode is accurately controlled so that the light quantity can be kept constant. In order to achieve the above object, a constant current element that outputs an identification current having a predetermined current value set in advance according to the rated current is used as the identification element of the illumination head, and the constant current element is branched from the illumination circuit. The power supply device is provided with a rated current that is set based on the current value of the identification signal output from the constant current element. A current setting circuit and a current control circuit for matching the current flowing through the lighting circuit with the rated current set by the rated current setting circuit are formed.

  FIG. 1 is a circuit diagram showing an example of an illumination device according to the present invention, FIG. 2 is a circuit diagram showing another embodiment of an illumination head used therefor, and FIG. 3 is a circuit diagram showing another embodiment of the illumination device. 4 is a circuit diagram showing another embodiment of the illumination head used for this.

Lighting device 1 shown in FIG. 1 is to be turned to connect the lighting head H to the power supply E ₁ by a cable 2.
Cable 2, three terminals 3S power supply _{E 1,} comprising 3G, and 3C, three terminals 4S lighting head H, 4G, three electric wires 5 ... a connecting together 4C, the connector 6 at both ends thereof, 6 is formed.

In the illumination head H, one or more light emitting diodes 8 are interposed in the illumination circuit 7 from the plus terminal 4S to the GND terminal 4G, and an identification current (identification signal) having a predetermined current value set in advance according to the rated current is provided. A constant current diode (constant current element) 9 for output is provided.
The constant current diode 9 is interposed in an identification circuit 10 that branches from the GND terminal 4G side of the illumination circuit 7 and reaches the identification current output terminal 4C.

The power supply unit E _1, feeding a power supply circuit 12 supplies a DC drive current to the lighting circuit 7 through the terminal 3S, rated current based on the identification current input from the output from the constant current diode 9 identifies the current input terminal 3C And a current control circuit 14 for matching the current flowing through the illumination circuit 7 with the rated current set by the rated current setting circuit 13.

The rated current setting circuit 13 includes an identification current detection circuit 15 that detects the current value of the identification current and converts it into a voltage, and a rated current setting device 16 that sets the rated current based on the detected voltage Vc.
When the current value of the identification current Ic output from the constant current diode 9 is Ic, the detection voltage Vc output from the identification current detection circuit 15 is determined by Vc = Ic × Rc, where Rc is a feedback resistance.
Since the feedback resistance Rc is constant and the identification current Ic does not change due to the internal resistance of the cable 2, the detection voltage Vc depends only on the current value Ic of the identification current regardless of the internal resistance of the cable 2.

Thus, by selecting the constant current diode 9 output current value varies depending on the rated current I _R, by detecting the identifying current Ic outputted from the constant current diode 9, respectively rated current I of the lighting head H ₁ of _R can be set accurately.
Therefore, in the rated current setter 16, when the detected voltage Vc is input, reads the rated current I _R that is set in advance in accordance with the voltage, the rated current I rated set corresponding to _R voltage Vs of the current control circuit 14 Output to.

  The current control circuit 14 includes a current limiting circuit 17 that limits a current flowing through the illumination circuit 7, a drive current detection circuit 18 that is connected to the GND terminal 4G of the illumination circuit 7 via the GND terminal 3G, and the detected drive current And a current regulator 19 for matching Id with the output of the current limiting circuit 17.

The current limiting circuit 17 is a circuit that outputs the smaller one of the input voltages. The rated setting voltage Vs output from the rated current setter 16 is input and the upper limit voltage Vmax that is the maximum value of the expected detection voltage Vc. Is input from the control voltage setting unit 20.
As a result, the upper limit voltage Vmax and the rated set voltage Vs are compared. Usually, the rated set voltage Vs ≦ Vmax is satisfied, so Vs is output. .

The drive current detection circuit 18 includes a transistor 21 serving as a current adjusting element and a detection resistor Rd that detects the drive current Id.
The current regulator 19 receives the output signal of the current limiting circuit 17 at its non-inverting input terminal, receives the detection signal from the detection resistor Rd of the drive current detection circuit 18 at its inverting input terminal, and outputs the control signal as a control signal. CS is input to the base of the transistor 21.
Thereby, the current value of the drive current Id flowing through the drive current detection circuit 19 is compared with the rated current, and the current flowing between the emitter and collector of the transistor 21 is adjusted so that they match.

The above is an example configuration of the present invention, and its operation will be described next.
The lighting head H ₁ is connected via a cable 2 to the power supply E _1, the driving current in a state of turning off the transistor 21 of the detecting circuit 18, when a predetermined voltage is applied from the power supply circuit 12, a part of the identification circuit 10, an identification current Ic having a current value corresponding to the rated current of the lighting head H ₁ is output from the constant current diode 9 and input to the rated current setting circuit 13 of the power supply device E ₁ via the cable 2. Is done. At this time, even if the internal resistance of the cable 2 increases, the identification current Ic does not change and is kept constant.

In the rated current setting circuit 13, the identification current Ic is input to the identification current detection circuit 15, converted into a voltage by the feedback resistor Rc, and the detected voltage Vc = Ic × Rc is output to the rated current setting device 16.
Since the identification current Ic does not change due to the internal resistance of the cable 2, the detection voltage Vc also depends only on the current value Ic of the identification current regardless of the internal resistance of the cable 2.
Thus, by selecting the constant current diode 9 output current value varies depending on the rated current I _R, by detecting the identifying current Ic outputted from the constant current diode 9, respectively rated current I of the lighting head H ₁ of _R is set correctly, the rated current I _R rating setting voltage Vs corresponding to the output from the rated current setting device 16 to the current control circuit 14.

Then, the detection voltage Vd detected by the drive current detection circuit 18 and the rated setting voltage Vs are compared by the current regulator 19, and the control signal CS is sent from the current regulator 19 to the base of the transistor 21 so that Vd = Vs. Is output, and the current flowing between the emitter and the collector is adjusted.
By this, the drive current Id flowing in the lighting circuit 7 regardless of the internal resistance of the cable 2 is controlled so as to coincide with the rated current I _R.

Figure 2 shows another illumination head H ₂ to be used in connection with a power supply unit E ₁ shown in FIG.
Lighting head of H ₂ present example, the identification circuit 10 to the constant current diode 9 is interposed, except that it is branching from the positive terminal 4G side lighting circuit 7 is common to the illumination head H _1.
Be used lighting head of H ₂ present embodiment, it is possible to set the rated current I _R in the same manner with the power supply device E _1, regardless of the internal resistance of the cable 2, the rated drive current Id flowing in the lighting circuit 7 it can be accurately maintained to the current I _R.
Since the control operation of the power supply device E ₁ in this case is the same as in Example 1, detailed description thereof will be omitted.

FIG. 3 shows another embodiment of the lighting device. In addition, the same code | symbol is attached to a common part with FIG. 1, and detailed description is abbreviate | omitted.
Lighting apparatus 31 of this example is to be turned to connect the lighting head H ₃ to the power supply E ₃ by a cable 32.
Cable 32 includes two terminals 3S power supply _{E 3,} and 3G, two terminals 4S lighting head _{H 3,} with two of the electric wire 5 ... a connecting together 4G, connectors 6,6 on both ends formed Has been.

Lighting head H _3, together with the lighting circuit 7 to one or more light emitting diode 8, from the positive terminal 4S to the GND terminal 4G is interposed, identified current (identification of previously set predetermined current value in accordance with the rated current A constant current diode (constant current element) 9 for outputting a signal is connected in series with the light emitting diode 8.
In addition, a bypass circuit 33 that bypasses the constant current diode 9 is formed in the illumination circuit 7, and the bypass circuit 33 has a predetermined identification current measurement time (for example, 1 second) after energization to the illumination circuit 7 is started. ) A timer switch 34 which is turned on when it passes is provided.

The power supply unit E _3, a power supply circuit 12 supplies a DC drive current to the lighting circuit 7 via the feed terminal 3S plus side, the rated current setting for setting a rated current based on the identification current outputted from the constant current diode 9 The circuit 13 and the current control circuit 14 for matching the current flowing through the illumination circuit 7 with the rated current set by the rated current setting circuit 13 are provided. The rated current setting circuit 13 and the current control circuit 14 are connected to the GND terminal 3G. Has been.

According to the illumination device 31, connected via a cable 32 to the lighting head H ₃ to the power supply E _3, a timer switch 34 interposed in the bypass circuit 33 of the lighting head H _3, the drive current detection circuit 18 When a predetermined voltage is applied from the power supply circuit 12 with the transistor 21 turned off, a part of the voltage is applied to the constant current diode 9 connected in series with the light emitting diode 8. identifying current Ic having a current value corresponding to the rated current of the head _{H 3} is output from the GND terminal 4G, it is inputted via the cable 32 to the GND terminal 3G power supply _{E 3.}

At this time, since the transistor 21 of the drive current detection circuit 18 is turned off, the identification current Ic is input to the rated current setting circuit 13, and the detection voltage Vc is output from the identification current detection circuit 15 to the rated current setting device 16. The rated current setting device 16 sets a rated setting voltage Vs according to the detected voltage Vc, stores this value, and outputs it to the current control circuit 14.
Since the identification current Ic does not change due to the internal resistance of the cable 32, the rated current can be accurately set by detecting the identification current Ic.

When the timer switch 34 is turned on after a predetermined time (for example, 1 second), the current control circuit 14 uses the current regulator 19 to detect the detected voltage Vd detected by the drive current detection circuit 18 and the rated setting voltage Vs. The control signal CS is output from the current regulator 19 to the base of the transistor 21 so that Vd = Vs, and the current flowing between the emitter and the collector is adjusted.
By this, the drive current Id flowing in the lighting circuit 7 regardless of the internal resistance of the cable 32 is controlled so as to coincide with the rated current I _R.

FIG. 4 shows another illumination device 41 that is used by connecting the illumination head H ₄ to the power supply device E ₄ . Note that parts common to those in FIG.
Lighting head H ₄ of the present embodiment, the lighting circuit 7 extending from the positive terminal 4S the GND terminal 4G with one or more light emitting diode 8 is interposed, preset predetermined current value in accordance with the rated current I _R The constant current diode (constant current element) 9 that outputs the identification current (identification signal) is connected in parallel with the light emitting diode 8.
The power supply device E ₄ is the same as the power supply device E _{3 of the} third embodiment shown in FIG. 3 except that the bias voltage V _B is applied to the non-inverting input terminal of the drive current detection circuit 18.

According to the illumination device 41, connected via a cable 32 to the lighting head H ₄ to the power supply E _4, the transistor 21 of the drive current detection circuit 18 in a state of off, from the power supply circuit 12, the light emitting diode 8 A reference voltage V ₀ (<V _F + V _B ) lower than the sum of the operating voltage V _F and the bias voltage V _B is supplied. At this time, the potential difference applied between the terminals 4S to 4G of the illumination circuit 7 is V ₀ −V _B. (<V _F ), which is less than the operating voltage V _{F of} the light emitting diode 8, so that the light emitting diode 8 is not turned on, and the identification current having a current value corresponding to the rated current of the lighting head H ₄ from the constant current diode 9 Ic is outputted from the GND terminal 4G, it is inputted via the cable 32 to the GND terminal 3G power supply _{E 4.}

Here, since the transistor 21 of the drive current detection circuit 18 is turned off, the identification current Ic is input to the rated current setting circuit 13, and the detection voltage Vc is output from the identification current detection circuit 15 to the rated current setting device 16. rated current I _R is read out in accordance with the rated current setting device 16 in the detection voltage Vc is set rated set voltage Vs corresponding to a current value of the rated current I _{R +} identification current Ic is outputted to the current control circuit 14 The
Since the identification current Ic does not change due to the internal resistance of the cable 32, the rated current can be accurately set by detecting the identification current Ic.

Then, in the current control circuit 14, the detection voltage Vd detected by the drive current detection circuit 18 and the rated setting voltage Vs are compared by the current regulator 19, and the current regulator 19 to the transistor 21 so that Vd = Vs. The control signal CS is output to the base of the power source, and the current flowing between the emitter and the collector is controlled to be the rated current I _R + the identification current Ic.
Here, if the rated current setting circuit 13 is cut off by a switch (not shown), the current Id flowing through the light emitting diode 8 of the illumination circuit 7 and the current Ic output from the constant current diode 9 all flow to the drive current detection circuit 18. If the current value is controlled to be the rated current I _R + the identification current Ic, the current flowing through the light emitting diode 8 is maintained at the rated current I _R.

  In the present invention, the supply current from the power supply device is automatically maintained at an appropriate current regardless of the specification of the illumination head, and the light emitting diode can always be lit at the rated value. It is suitable for use in which it is arbitrarily replaced with.

The circuit diagram which shows an example of the illuminating device which concerns on this invention. The circuit diagram which shows other embodiment of the illumination head used for this. The circuit diagram which shows other embodiment of an illuminating device. The circuit diagram which shows other embodiment of an illuminating device. The circuit diagram which shows a conventional apparatus.

Explanation of symbols

1, 31, 41 Lighting device
H _{1 to} H ₄ lighting heads E _{1 to} E ₄ power supply device 7 lighting circuit 8 light emitting diode 9 constant current diode (constant current element)
DESCRIPTION OF SYMBOLS 10 Identification circuit 12 Power supply circuit 13 Rated current setting circuit 14 Current control circuit 15 Identification current detection circuit 16 Rated current setting device 17 Current limiting circuit 18 Drive current detection circuit 19 Current regulator

Claims (3)

When an illumination head including an illumination circuit including one or more light emitting diodes and an identification element for identifying the rated current thereof is connected to the power supply apparatus, the power supply apparatus is configured to respond to an identification signal output from the identification element. A lighting device that supplies a rated current and lights a light emitting diode of a lighting head,
In the lighting head, a constant current element that outputs an identification current having a predetermined current value set in advance according to a rated current as an identification element is connected in series with the light emitting diode,
The power supply device includes a rated current setting circuit that sets a rated current based on a current value of an identification signal output from the constant current element, and a current that flows through a lighting circuit to a rated current set by the rated current setting circuit. A matching current control circuit is formed,
An illumination device , wherein a bypass switch that bypasses the constant current element is provided with a timer switch that is turned on when a preset identification current measurement time has elapsed after the start of energization of the illumination circuit. An illumination circuit including one or more light emitting diodes and an identification element for identifying the rated current are provided, and the rated current is supplied according to an identification signal output from the identification element when connected to a power supply device. An illumination head that receives the light emitting diode and receives the light,
As the identification element, a constant current element that outputs an identification current having a predetermined current value set in advance according to a rated current is connected in series with the light emitting diode,
An illumination head, wherein a bypass switch that bypasses the constant current element is provided with a timer switch that is turned on when a predetermined identification current measurement time has elapsed after the start of energization of the illumination circuit. The rated current setting circuit includes an identification current detection circuit that outputs a detection voltage corresponding to the current value of the identification current, and a rated current setting device that outputs a rated setting voltage according to the rated current based on the detection voltage,
The lighting device according to claim 1, wherein the current control circuit includes a current limiting circuit that limits a current flowing through the lighting circuit when the rated setting voltage exceeds a preset upper limit voltage.

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