JP2017199590A - LED lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED lamp lighting device which allows for cost reduction of product and compaction of a device, because a circuit for changing an overcurrent into heat can be eliminated, by configuring not to generate overcurrent.SOLUTION: An LED lamp lighting device 1 can be switched to connection state for supplying a current from an LED lamp drive control circuit 10 to a lamp circuit 13 and a bypass circuit 16 while detouring a lamp circuit 14, when a current cannot be supplied from the LED lamp drive control circuit 10 to the lamp circuit 14 due to abnormality, and when switching is made to this connection state, an impressed voltage to be applied from the LED lamp drive control circuit 10 to the lamp circuit 13 is lowered below a drive voltage applied to the lamp circuit 13 for constant current drive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an LED lamp lighting device for driving an LED lamp.

  In recent years, demands for reducing environmental loads on vehicles such as motorcycles and automobiles have become stricter, and in response to such demands, there has been an increasing trend to reduce fuel consumption and improve fuel efficiency.

  In such a flow, the vehicle headlamp requires a large amount of light, and thus consumes a large amount of power. Therefore, in recent years, as a headlight of a vehicle, an LED (light emitting diode) with low power consumption has been used as a light source instead of a filament lamp or a xenon discharge lamp that has been used as a light source for many years. ing.

  A headlamp that uses such an LED as a light source cannot obtain a large amount of light with a single LED compared to a filament lamp or a xenon discharge lamp. Therefore, a plurality of LEDs are connected in series, connected in parallel, or a combination thereof. Connected configuration.

  For headlamps that use LEDs as light sources, current flows in both the high beam and the low beam and both the high beam and the low beam are lit, and the current flows only in the low beam and only the low beam is lit. Are known to be switched by a dimmer switch.

  In such a configuration, when the high beam side LED becomes abnormal, the high beam side LED is in an open state and is not energized, but the low beam side LED can be turned on by switching the dimmer switch to the low side. it can. On the other hand, when the LED on the low beam side is damaged, the LED on the low beam side is in an open state and is not energized, and both the high beam side LED and the low beam side LED are not lit even when the dimmer switch is switched.

  On the other hand, Patent Document 1 discloses an LED lamp lighting device that avoids a state where both the high beam side LED and the low beam side LED are not lit when the low beam side LED is damaged. In the LED lamp lighting device disclosed in Patent Document 1, when the low beam side LED is broken, the dimmer switch is switched to the high side, a predetermined voltage is applied to the Zener diode, and a predetermined current flows through the thyristor. When the thyristor is turned on, a current flows through the high beam LED, and the high beam LED is turned on.

  On the other hand, in the LED lamp lighting device disclosed in Patent Document 1, since the power supply voltage at the moment when the thyristor is turned on is boosted to a predetermined voltage using a booster circuit, the forward voltage and the drive voltage of the thyristor Is greater than the sum of As a result, in the LED lamp lighting device disclosed in Patent Document 1, when the thyristor is turned on, an overcurrent larger than the rated current of the LED flows by overshooting the rated current of the LED, so that the high beam side The LED may be damaged.

  On the other hand, patent document 2 is disclosing the LED lamp lighting device which suppresses said overcurrent. The LED lamp lighting device disclosed in Patent Document 2 includes a protection circuit that discharges a current exceeding the rated current of the LED by changing it to heat using a transistor or a protective resistor. According to the LED lamp lighting device disclosed in Patent Document 2, the overcurrent can be suppressed by the protection circuit.

JP 2014-120444 A Japanese Patent No. 5635209

  Here, according to the study of the present inventor, the LED lamp lighting device disclosed in Patent Document 2 is a transistor or a protective resistor having a large allowable maximum power so that it can withstand the power burden when changing to heat. This increases the cost of the product and increases the size of the apparatus.

  The present invention has been made through the above-described studies. By adopting a configuration that does not generate overcurrent, a circuit that changes overcurrent into heat can be eliminated, thereby reducing the cost of the product. It is an object of the present invention to provide an LED lamp lighting device that can reduce the size of the device.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided an LED lamp lighting device for driving an LED lamp, the first lamp comprising a single LED lamp or a plurality of LED lamps connected in series. A lamp circuit, a second lamp circuit connected in series to the first lamp circuit, comprising one LED lamp or a plurality of LED lamps connected in series, and a current supply from the power supply unit An LED lamp drive control unit for driving the first lamp circuit and the second lamp circuit; and when the current cannot be supplied from the LED lamp drive control unit to the second lamp circuit due to an abnormality, the LED A bypass circuit to which a current is supplied from a lamp drive control unit; and when the abnormality occurs, the power supply unit bypasses the second lamp circuit and bypasses the second lamp circuit. And a switch that can be switched to a connected state for supplying a current to the bypass circuit, and the LED lamp drive control unit has the first lamp when the switch is in the connected state. An LED lamp lighting device characterized in that an applied voltage applied to a circuit is lower than a drive voltage applied to the first lamp circuit in order to drive the first lamp circuit at a constant current.

  In addition to the first aspect, the present invention provides the LED lamp drive controller after the applied voltage is lowered below the drive voltage when the switch is in the connected state. A second aspect is that the applied voltage is boosted so that a current supplied to one lamp circuit becomes a target value when the first lamp circuit is driven at a constant current.

  In addition to the first or second aspect of the present invention, the LED lamp drive control unit has a voltage at which the bypass circuit does not turn off when the switch is in the connected state, and the first A third aspect is to lower the applied voltage to a voltage that can supply a current that does not cause an overcurrent to the lamp circuit.

  According to the present invention, in addition to any of the first to third aspects, the LED drive control unit includes a booster circuit that boosts the applied voltage, the booster circuit, the first lamp circuit, and the And a protection circuit comprising a switching element connected between the second lamp circuit and a resistor connected in parallel with the switching element, and the voltage on the booster circuit side of the protection circuit is The detection as the applied voltage is a fourth aspect.

  According to the present invention, in addition to any of the first to third aspects, the LED drive control unit includes a booster circuit that boosts the applied voltage, the booster circuit, the first lamp circuit, and the A protection circuit comprising a switching element connected between the second lamp circuit and a resistor connected in parallel with the switching element, the first lamp circuit of the protection circuit, and the The fifth aspect is to detect the voltage on the second lamp circuit side as the applied voltage.

  The LED lamp lighting device according to the first aspect of the present invention is an LED lamp lighting device that drives an LED lamp, and includes a first lamp circuit including one LED lamp or a plurality of LED lamps connected in series. A second lamp circuit connected in series to the first lamp circuit, comprising one LED lamp or a plurality of LED lamps connected in series, and a first lamp by receiving a current supply from a power supply unit LED lamp drive control unit for driving the circuit and the second lamp circuit, and when the current cannot be supplied from the LED lamp drive control unit to the second lamp circuit due to an abnormality, current is supplied from the LED lamp drive control unit. A bypass circuit that bypasses the second lamp circuit from the power supply unit and causes the current to flow to the first lamp circuit and the bypass circuit when an abnormality occurs. A switch that can be switched to a connection state to be supplied, and the LED lamp drive control unit applies an applied voltage to the first lamp circuit when the switch is in the connection state. Since the driving voltage applied to the first lamp circuit is lower than the driving voltage applied to the first lamp circuit in order to perform constant current driving, a circuit that changes the overcurrent into heat can be eliminated by adopting a configuration that does not generate overcurrent. Therefore, the cost of the product can be reduced and the apparatus can be miniaturized.

  In the LED lamp lighting device according to the second aspect of the present invention, when the LED lamp drive control unit lowers the applied voltage below the drive voltage when the switch is in the connected state, the LED lamp drive control unit sets the first lamp circuit. Since the applied voltage is boosted so that the supplied current becomes a target value when the first lamp circuit is driven with constant current, the first lamp circuit is driven with constant current without causing an overcurrent. Can do.

  In the LED lamp lighting device according to the third aspect of the present invention, when the LED lamp drive control unit is in a connected state, the voltage that does not turn off the bypass circuit and the overcurrent with respect to the first lamp circuit. Since the applied voltage is lowered to a voltage that can supply a current that cannot be supplied, even if an abnormality occurs in the second lamp circuit, the first lamp circuit can be turned on without damaging the LED. .

  In the LED lamp lighting device according to the fourth aspect of the present invention, the LED drive control unit is connected between the booster circuit that boosts the applied voltage, and the booster circuit, the first lamp circuit, and the second lamp circuit. And a protection circuit including a resistor connected in parallel with the switching element, and detects a voltage on the booster circuit side of the protection circuit as an applied voltage. Can be controlled to prevent overcurrent.

  In the LED lamp lighting device according to the fifth aspect of the present invention, the LED drive control unit is connected between the booster circuit that boosts the applied voltage, and the booster circuit, the first lamp circuit, and the second lamp circuit. And a protection circuit comprising a switching element connected in parallel with the switching element, and detecting a voltage on the first lamp circuit side and the second lamp circuit side of the protection circuit as an applied voltage Therefore, it is possible to prevent the overcurrent from occurring by controlling the voltages on the first lamp circuit side and the second lamp circuit side.

FIG. 1 is a block diagram showing a configuration of an LED lamp lighting device according to the first embodiment of the present invention. FIG. 2 is a flowchart and timing chart showing the LED lamp abnormality drive processing in the first embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of the LED lamp lighting device according to the second embodiment of the present invention. FIG. 4 is a flowchart and timing chart showing the LED lamp abnormality drive processing in the second embodiment of the present invention.

  Hereinafter, an LED lamp lighting device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

(First embodiment)
<Configuration of LED lamp lighting device>
First, with reference to FIG. 1, it demonstrates in detail about the structure of the LED lamp lighting device in this embodiment.

  FIG. 1 is a block diagram showing a configuration of an LED lamp lighting device according to the first embodiment of the present invention.

  As shown in FIG. 1, the LED lamp lighting device 1 in this embodiment is mounted on a vehicle such as a motorcycle.

  The power supply unit 21 rectifies an output voltage from a battery or an AC generator (not shown) and supplies the rectified voltage to the booster circuit 11.

  The LED lamp lighting device 1 includes a booster circuit 11, a drive control unit 12, a lamp circuit 13, a lamp circuit 14, a switch 15, and a bypass circuit 16. The LED lamp drive control unit 10 includes a drive control unit 12 and a booster circuit 11, and supplies current to the lamp circuit 13 and the lamp circuit 14 by receiving supply of current from the power supply unit 21. 13 and the ramp circuit 14 are driven.

  The booster circuit 11 boosts the voltage supplied from the power supply unit 21 under the control of the drive control unit 12 to a voltage equal to or higher than the forward voltage of the lamp circuit 13 and the lamp circuit 14, and the current supplied from the power supply unit 21. Is supplied to the drive control unit 12.

  The drive control unit 12 reads a necessary control program and control data from a memory (not shown) and controls the current supplied to the lamp circuit 13 so as not to become an overcurrent.

  Specifically, the drive control unit 12 includes a voltage monitoring unit 121, a boost control unit 122, a gate control unit 123, and a protection circuit 124.

Voltage monitor 121 detects a voltage _{V D} of the booster circuit 11-side of the protection circuit 124, and outputs an electrical signal indicating the detected value of the voltage _{V D} to the boost control unit 122.

The boost control unit 122 controls the boost circuit 11 and the gate control unit 123 based on the detected value of the voltage V _D indicated by the electrical signal input from the voltage monitoring unit 121.

  The gate control unit 123 controls the voltage applied to the gate terminal of the switching element Q1 of the protection circuit 124 under the control of the boost control unit 122, and turns on or off the gate of the switching element Q1.

  The protection circuit 124 is a constant current circuit, and includes a switching element Q1 connected between the booster circuit 11, the ramp circuit 13, and the ramp circuit 14, and a resistor R1 connected in parallel with the switching element Q1. Yes. The gate of the switching element Q1 is turned ON or OFF under the control of the gate control unit 123. The protection circuit 124 supplies the current supplied from the booster circuit 11 to the ramp circuit 13 and the ramp circuit 14 through the resistor R1 when the gate of the switching element Q1 is turned off. The protection circuit 124 supplies the current supplied from the booster circuit 11 to the ramp circuit 13 and the ramp circuit 14 via the switching element Q1 and the resistor R1 when the gate of the switching element Q1 is turned on. To the lamp circuit 13 and the lamp circuit 14 side.

  The lamp circuit 13 includes one LED lamp or a plurality of LED lamps connected in series. The lamp circuit 13 is driven when the current is supplied from the drive control unit 12 to turn on the LED lamp, and when the supply of current from the drive control unit 12 is stopped, the drive is stopped and the LED lamp is turned off. To do.

  The lamp circuit 14 includes one LED lamp or a plurality of LED lamps connected in series. The lamp circuit 14 is connected to the lamp circuit 13 in series. The lamp circuit 14 is driven to turn on the LED lamp when current is supplied from the drive control unit 12 to the LED lamp lighting device 1, and stops driving when supply of current from the drive control unit 12 is stopped. Then turn off the LED lamp.

  The switch 15 includes a terminal 15a connected to the output terminal of the lamp circuit 13, a terminal 15b connected to the output terminal of the drive control unit 12, a terminal 15c connected to the input terminal of the bypass circuit 16, It has. The switch 15 supplies the current supplied from the drive control unit 12 to the ramp circuit 14 when the low-side connection state connecting the terminal 15a and the terminal 15b is established, and connects the terminal 15a and the terminal 15c to the high side. A current supplied from the drive control unit 12 via the lamp circuit 14 when the connection state is established is supplied to the bypass circuit 16.

  The bypass circuit 16 is connected in series with the lamp circuit 13 when the switch 15 is in a high-side connection state. A current is supplied to the bypass circuit 16 from the drive control unit 12 when the switch 15 is in a high-side connection state.

<LED lamp abnormality drive processing>
Next, with reference to FIG. 2, the LED lamp abnormality driving process in the present embodiment will be described in detail.

  FIG. 2 is a flowchart and timing chart showing the LED lamp abnormality drive processing in the first embodiment of the present invention. 2A is a flowchart showing the LED lamp abnormality driving process, and FIG. 2B is a timing chart of the LED lamp abnormality driving process.

  In the flowchart shown in FIG. 2A, when an abnormality occurs in the lamp circuit 14, the switch 15 is brought into a high-side connection state in which the terminals 15 a and 15 c are connected, and the power supply unit 21 passes through the booster circuit 11. The drive process at the time of LED lamp abnormality when the electric current is supplied to the drive control part 12 is shown.

  First, in the process of step S1, the boost control unit 122 controls the booster circuit 11 so as to stop the boosting operation. Thereby, the process of step S1 is completed, and the LED lamp abnormality drive process proceeds to the process of step S2.

  In the process of step S <b> 2, the gate control unit 123 turns off the gate under the control of the boost control unit 122. Thereby, the process of step S2 is completed, and the LED lamp abnormality drive process proceeds to the process of step S3.

  In the process of step S3, the boost controller 122 controls the booster circuit 11 so as to start the boosting operation. Thereby, the process of step S3 is completed, and the LED lamp abnormality drive process proceeds to the process of step S4.

When the booster circuit 11 starts the boosting operation, the voltage V _D on the booster circuit 11 side of the protection circuit 124 gradually increases and reaches V _OVS at time t _SCRON as shown in FIG. Bypass circuit 16 is turned on at time t _SCRON when voltage V _D reaches V _OVS .

Further, the current supplied from the power supply unit 21 to the drive control unit 12 via the booster circuit 11 does not flow into the switching element Q1 of the protection circuit 124 when the bypass circuit 16 is turned on. Flows through R1. Then, the output current I ₀ of the drive control unit 12 is supplied to the ramp circuit 13 and the bypass circuit 16. As a result, the current value of the output current I ₀ of the drive control unit 12 rises to I _{SCRON at} time t _SCRON as shown in FIG. The voltage V _D gradually increases after the bypass circuit 16 is turned on.

In the process of step S4, the voltage monitoring unit 121 detects the voltage V _D on the booster circuit 11 side of the protection circuit 124, and determines whether or not the voltage V _D is equal to or higher than the threshold value V _DH . As a result of the determination, when the voltage V _D is less than the threshold value V _DH , the process of step S4 is repeated. On the other hand, if the determination result shows that the voltage V _D is equal to or higher than the threshold value V _DH , the voltage monitoring unit 121 outputs a signal indicating that the voltage V _D is equal to or higher than the threshold value V _DH to the boost control unit 122. The LED lamp abnormality drive process proceeds to step S5.

Specifically, as shown in FIG. 2B, the voltage V _D is less than the threshold value V _DH until time t _DRVSTP , and in this case, the process of step S4 is repeated. At this time, the output current I ₀ of the drive control unit 12 gradually increases from I _SCRON . On the other hand, the voltage V _D becomes _equal to or higher than the threshold V _{DH at} time t _DRVSTP , and in this case, a signal indicating that the voltage V _D is equal to or higher than the threshold V _DH is output from the voltage monitoring unit 121 to the boost control unit 122. .

  In the processing of step S5, the boost control unit 122 controls the booster circuit 11 so as to stop the boosting operation. Thereby, the process of step S5 is completed, and the LED lamp abnormality drive process proceeds to the process of step S6.

By boosting circuit 11 stops the boosting operation, the voltage _{V D} of the booster circuit 11-side of the protection circuit 124, as shown in FIG. 2 (b), the forward voltage gradually decreases from time _{t DRVSTP V F} And the value of V _SCRON, and further lower than this addition value. At this time, since the current value of the output current I ₀ of the drive control unit 12 is _{equal to} or higher than I _SCRON , the bypass circuit 16 is not turned off.

In the process of step S6, the voltage monitoring unit 121 detects the voltage V _D on the booster circuit 11 side of the protection circuit 124, and determines whether or not the voltage V _D has decreased to the threshold value V _DL . As a result of the determination, if the voltage V _D has not decreased to the threshold value V _DL , the process of step S6 is repeated. On the other hand, as a result of the determination, when the voltage V _D decreases to the threshold value V _DL , the voltage monitoring unit 121 outputs a signal indicating that the voltage V _D has decreased to the threshold value V _DL to the boost control unit 122. The LED lamp abnormality drive process proceeds to step S7.

Specifically, as shown in FIG. 2B, the voltage V _D is larger than the threshold value V _DL until time t _DRVSTRT . In this case, the process of step S6 is repeated. On the other hand, at time t _DRVSTRT , the voltage V _D decreases to the threshold value V _DL , and in this case, a signal indicating that the voltage V _D has decreased to the threshold value V _DL is output from the voltage monitoring unit 121 to the boost control unit 122. To do.

Here, the threshold value V _DL is a voltage that can supply an output current I ₀ that does not turn off the bypass circuit 16 and a voltage that can supply a current that does not become an overcurrent to the ramp circuit 13, and is a forward voltage V _F. The voltage is set lower than the added value with V _SCRON . Therefore, the current supplied from the power supply unit 21 to the drive control unit 12 via the booster circuit 11 flows to the switching element Q1 of the protection circuit 124 even when the voltage V _D drops to the threshold value V _DL. If not, the resistor R1 of the protection circuit 124 continues to flow. Then, the output current I ₀ of the drive control unit 12 is continuously supplied to the lamp circuit 13 and the bypass circuit 16.

  In the process of step S7, the gate control unit 123 turns on the gate of the switching element Q1 under the control of the boost control unit 122. Thereby, the process of step S7 is completed, and the LED lamp abnormality drive process proceeds to the process of step S8.

  In the process of step S8, the boost control unit 122 starts a boost operation.

When the boost control unit 122 starts the boost operation, the voltage V _D on the boost circuit 11 side of the protection circuit 124 gradually increases and stabilizes at a predetermined value. As a result, the lamp circuit 13 enters a constant current drive state.

Specifically, as shown in FIG. 2B, the voltage V _D on the booster circuit 11 side of the protection circuit 124 gradually rises from the threshold value V _DL, and at the time t _CONST , the forward voltages V _F and V _SCRON Is reached, and a stable constant current driving state is achieved with this addition value. Here, the added value of the forward voltage V _F and V _SCRON is a drive voltage applied to the ramp circuit 13 in order to drive the ramp circuit 13 at a constant current. As a result, the lamp circuit 13 enters a constant current drive state.

The current supplied from the power supply unit 21 to the drive control unit 12 via the booster circuit 11 flows through the resistor R1 and the switching element Q1 of the protection circuit 124. Then, the output current I ₀ of the drive control unit 12 is supplied to the ramp circuit 13 and the bypass circuit 16. Accordingly, the current value of the output current I ₀ of the drive control unit 12 is increased at once to a rated current I _F of the LED lamp as shown in FIG. 2 (b). However, the output current I ₀ of the drive control unit 12, since the booster circuit 11 to the voltage V _D falls below the threshold value V _DL does not start the boost does not exceed the rated current I _F.

  Thereby, the process of step S8 is completed, and the LED lamp abnormality time driving process ends.

  In the LED lamp lighting device 1 according to the embodiment of the present invention, when the current cannot be supplied from the drive control unit 12 to the lamp circuit 14 due to an abnormality, the lamp circuit 13 bypasses the lamp circuit 14 from the drive control unit 12. The connection state for supplying a current to the bypass circuit 16 can be switched, and when the connection state is switched, the voltage applied to the lamp circuit 13 from the drive control unit 12 is applied to the ramp circuit 13 by constant current driving. Therefore, by lowering the driving voltage applied to the lamp circuit 13 to prevent the overcurrent from being generated, the circuit for changing the overcurrent into heat can be eliminated, thereby reducing the cost of the product. And the size of the apparatus can be reduced.

  In the LED lamp lighting device 1 according to the embodiment of the present invention, the applied voltage is switched when the drive control unit 12 is switched to a connection state that bypasses the lamp circuit 14 and supplies current to the lamp circuit 13 and the bypass circuit 16. After the voltage is lowered below the drive voltage, the applied voltage is boosted so that the current supplied from the drive control unit 12 to the lamp circuit 13 becomes a target value when the lamp circuit 13 is driven at a constant current. Constant current driving can be performed without generating current.

  Further, in the LED lamp lighting device 1 according to the embodiment of the present invention, when the drive control unit 12 bypasses the lamp circuit 14 and is switched to a connection state in which current is supplied to the lamp circuit 13 and the bypass circuit 16, the bypass circuit Since the applied voltage is reduced to a voltage at which the voltage 16 does not turn off and the voltage that can supply a current that does not cause an overcurrent to the lamp circuit 13, the lamp circuit 13 can be lit without damaging the LED.

  Further, in the LED lamp lighting device 1 according to the embodiment of the present invention, the booster circuit 11 that boosts the applied voltage, the switching element Q1 connected between the booster circuit 11, the lamp circuit 13, and the lamp circuit 14, and the switching element A protection circuit 124 including a resistor R1 connected in parallel with Q1, and detects the voltage on the booster circuit 11 side of the protection circuit 124 as an applied voltage. It can be controlled to prevent overcurrent.

(Second Embodiment)
<Configuration of LED lamp lighting device>
First, with reference to FIG. 3, it demonstrates in detail about the structure of the LED lamp lighting device in this embodiment.

  FIG. 3 is a block diagram showing the configuration of the LED lamp lighting device according to the second embodiment of the present invention.

  3, parts having the same configuration as in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 3, the LED lamp lighting device 2 in this embodiment is mounted on a vehicle such as a motorcycle.

  The LED lamp lighting device 2 includes a booster circuit 11, a drive control unit 22, a lamp circuit 13, a lamp circuit 14, a switch 15, and a bypass circuit 16. The LED lamp drive control unit 20 includes a drive control unit 22 and a booster circuit 11, and supplies current to the lamp circuit 13 and the lamp circuit 14 by receiving supply of current from the power supply unit 21, thereby supplying the lamp circuit. 13 and the ramp circuit 14 are driven.

  The booster circuit 11 boosts the voltage supplied from the power supply unit 21 under the control of the drive control unit 22 to a voltage equal to or higher than the forward voltage of the lamp circuit 13 and the lamp circuit 14, and the current supplied from the power supply unit 21. Is supplied to the drive control unit 22.

  The drive control unit 22 reads a necessary control program and control data from a memory (not shown) and controls the current supplied to the lamp circuit 13 so as not to become an overcurrent.

  Specifically, the drive control unit 22 includes a gate control unit 123, a protection circuit 124, a voltage monitoring unit 221, and a boost control unit 222.

The voltage monitoring unit 221 detects the voltage V _LED on the lamp circuit 13 and lamp circuit 14 side of the protection circuit 124, and outputs an electrical signal indicating the detected value of the voltage V _LED to the boost control unit 222.

The boost control unit 222 controls the boost circuit 11 and the gate control unit 123 based on the detected value of the voltage V _LED indicated by the electric signal input from the voltage monitoring unit 221.

  The gate control unit 123 controls the voltage applied to the gate terminal of the switching element Q1 of the protection circuit 124 under the control of the boost control unit 222, and turns on or off the gate of the switching element Q1.

  The lamp circuit 13 is driven when the current is supplied from the drive control unit 22 to turn on the LED lamp, and when the supply of current from the drive control unit 22 is stopped, the drive is stopped and the LED lamp is turned off. To do.

  The lamp circuit 14 is driven when the current is supplied from the drive control unit 22 to turn on the LED lamp, and when the supply of current from the drive control unit 22 is stopped, the drive is stopped and the LED lamp is turned off. To do.

  The switch 15 includes a terminal 15a connected to the output terminal of the lamp circuit 13, a terminal 15b connected to the output terminal of the drive control unit 22, a terminal 15c connected to the input terminal of the bypass circuit 16, It has.

<LED lamp abnormality drive processing>
Next, with reference to FIG. 4, the LED lamp abnormality driving process in the present embodiment will be described in detail.

  FIG. 4 is a flowchart and timing chart showing the LED lamp abnormality drive processing in the second embodiment of the present invention. In FIG. 4, FIG. 4A is a flowchart showing the LED lamp abnormality drive process, and FIG. 4B is a timing chart of the LED lamp abnormality drive process.

  In the flowchart shown in FIG. 4A, when an abnormality occurs in the lamp circuit 14, the switch 15 is brought into a high-side connection state in which the terminals 15 a and 15 c are connected, and the power supply unit 21 passes through the booster circuit 11. The drive process at the time of LED lamp abnormality when the electric current is supplied to the drive control part 22 is shown.

  First, in the process of step S11, the boost control unit 222 stops the boost operation. Thereby, the process of step S11 is completed, and the LED lamp abnormality drive process proceeds to the process of step S12.

  In the process of step S <b> 12, the gate control unit 123 turns off the gate under the control of the boost control unit 222. Thereby, the process of step S12 is completed, and the LED lamp abnormality time driving process proceeds to the process of step S13.

  In the processing of step S13, the boost control unit 222 controls the booster circuit 11 so as to start the boosting operation. Thereby, the process of step S13 is completed, and the LED lamp abnormality drive process proceeds to the process of step S14.

When the booster circuit 11 starts the boosting operation, the voltage V _LED on the ramp circuit 13 and ramp circuit 14 side of the protection circuit 124 gradually rises to V at time t _SCRON as shown in FIG. _{Reach OVS} . Bypass circuit 16 is turned on at time t _SCRON when voltage V _LED reaches V _OVS .

Further, the current supplied from the power supply unit 21 to the drive control unit 22 via the booster circuit 11 does not flow into the switching element Q1 of the protection circuit 124 when the bypass circuit 16 is turned on. Flows through R1. Then, the output current I ₀ of the drive control unit 22 is supplied to the lamp circuit 13 and the bypass circuit 16. As a result, the current value of the output current I ₀ of the drive control unit 22 rises to I _{SCRON at} time t _SCRON as shown in FIG.

In the process of step S14, the voltage monitoring unit 221 detects the voltage V _LED on the lamp circuit 13 and the lamp circuit 14 side of the protection circuit 124, and determines whether or not the voltage V _LED is equal to or less than the threshold value V _LEDL . As a result of the determination, when the voltage V _LED is larger than the threshold value V _LEDL , the process of step S14 is repeated. On the other hand, as a result of the determination, if the voltage V _LED is _{equal to} or lower than the threshold V _LEDL , the voltage monitoring unit 221 outputs a signal indicating that the voltage V _LED is _{equal to} or lower than the threshold V _LEDL to the boost control unit 222. The LED lamp abnormality drive process proceeds to step S15.

Specifically, as shown in FIG. 4B, the voltage V _LED on the lamp circuit 13 and lamp circuit 14 side of the protection circuit 124 becomes equal to or lower than the threshold value V _LEDL at time t _SCRON , and in this case, voltage monitoring The unit 121 outputs a signal indicating that the voltage V _LED is _{equal to} or lower than the threshold value V _LEDL to the boost control unit 122.

  In the process of step S15, the boost control unit 222 controls the booster circuit 11 to stop the boosting operation. Thereby, the process of step S15 is completed, and the LED lamp abnormality drive process proceeds to the process of step S16.

When the boosting control unit 222 stops the boosting operation at time t _DRVSTP , the voltage V _LED on the lamp circuit 13 and lamp circuit 14 side of the protection circuit 124 gradually decreases as shown in FIG. 4B. lower than the forward voltage V _F. Further, the output current I ₀ of the drive control unit 22 continues to be supplied to the lamp circuit 13 and the bypass circuit 16 and gradually decreases from time t _DRVSTP . At this time, since the current value of the output current I ₀ of the drive control unit 22 is _{equal to} or higher than I _SCRON , the bypass circuit 16 is not turned off.

In the process of step S16, the boost control unit 222 determines whether or not a predetermined time T _DCHRG has elapsed since the time when the boost operation was stopped. As a result of the determination, if the predetermined time T _DCHRG or more has not elapsed since the time when the boosting operation was stopped, the process of step S16 is repeated. On the other hand, as a result of the determination, when a predetermined time T _DCHRG or more has elapsed from the time when the boost operation is stopped, the boost control unit 222 controls the gate control unit 123 to _{turn on} the gate of the switching element Q1, and the LED The lamp abnormality driving process proceeds to step S17.

Specifically, as shown in FIG. 4 (b), since the until time _{t DRVSTRT} not elapsed from the time _{t DRVSTP} predetermined time _{T DCHRG} above, in this case, the step-up control unit 222, step S16 Repeat the process. On the other hand, at time t _DRVSTRT , since the predetermined time T _DCHRG has elapsed from time t _DRVSTP , in this case, the boost control unit 222 controls the gate control unit 123 to _{turn on} the gate of the switching element Q1.

Here, the predetermined time T _DCHRG is the time during which the current value of the output current I ₀ of the drive control unit 22 does not decrease to I _SCRON when the bypass circuit 16 is turned off, and the voltage on the lamp circuit 13 and lamp circuit 14 side of the protection circuit 124. V _LED is set to a time that is discharged to below the forward voltage _{V F} is a voltage lower than the sum of the forward voltage _{V F} and _{V SCRON.} Therefore, the output current I ₀ of the drive control unit 22 continues to be supplied to the lamp circuit 13 and the bypass circuit 16 even when the predetermined time T _DCHRG has elapsed.

  In the process of step S <b> 17, the gate control unit 123 turns on the gate of the switching element Q <b> 1 under the control of the boost control unit 222. Thereby, the process of step S17 is completed, and the LED lamp abnormality drive process proceeds to the process of step S18.

  In the process of step S18, the boost control unit 222 controls the booster circuit 11 to start the boosting operation.

When the booster circuit 11 starts the boosting operation, the voltage V _LED on the ramp circuit 13 and ramp circuit 14 side of the protection circuit 124 gradually increases and stabilizes at a predetermined value. As a result, the lamp circuit 13 enters a constant current drive state.

Specifically, the voltage V _LED on the ramp circuit 13 and ramp circuit 14 side of the protection circuit 124 gradually increases from time t _DRVSTRT and forward voltage V V at time t _CONST as shown in FIG. The sum of _F and V _SCRON is reached, and a constant current drive state that is stable at this sum is obtained. As a result, the lamp circuit 13 enters a constant current drive state.

The current supplied from the power supply unit 21 to the drive control unit 22 via the booster circuit 11 flows through the resistor R1 and the switching element Q1 of the protection circuit 124. The output current I ₀ of the drive control unit 22, by supplying to the lamp circuit 13 and the bypass circuit 16, rises at once to the rated current I _F of the LED lamp as shown in Figure 4 (b). However, the output current _{I 0} of the drive control unit 22 because it does not initiate booster from the time _{t DRVSTP} stopping the boosting operation until a predetermined time has elapsed _{T DCHRG} above, does not exceed the rated current _{I F.}

  Thereby, the process of step S18 is completed and the drive process at the time of LED lamp abnormality is complete | finished.

  In the LED lamp lighting device 2 in the above embodiment of the present invention, when the current cannot be supplied from the drive control unit 22 to the lamp circuit 14 due to an abnormality, the lamp circuit 13 bypasses the lamp circuit 14 from the drive control unit 22. The connection state for supplying current to the bypass circuit 16 can be switched. When the connection state is switched, the voltage applied from the drive control unit 22 to the lamp circuit 13 is driven by the constant current driving of the lamp circuit 13. Therefore, by lowering the driving voltage applied to the lamp circuit 13 to prevent the overcurrent from being generated, the circuit for changing the overcurrent into heat can be eliminated, thereby reducing the cost of the product. And the size of the apparatus can be reduced.

  Further, in the LED lamp lighting device 2 according to the embodiment of the present invention, the applied voltage is switched when the drive control unit 22 is switched to a connection state that bypasses the lamp circuit 14 and supplies current to the lamp circuit 13 and the bypass circuit 16. After the voltage is lowered below the drive voltage, the applied voltage is boosted so that the current supplied from the drive control unit 22 to the lamp circuit 13 becomes a target value when the lamp circuit 13 is driven at a constant current. Constant current driving can be performed without generating current.

  Further, in the LED lamp lighting device 2 according to the embodiment of the present invention, the booster circuit 11 that boosts the applied voltage, the switching element Q1 connected between the booster circuit 11, the lamp circuit 13, and the lamp circuit 14, and the switching element A protection circuit 124 including a resistor R1 connected in parallel with Q1, and detects the voltage on the ramp circuit 13 and ramp circuit 14 side of the protection circuit 124 as an applied voltage. In addition, the voltage on the lamp circuit 14 side can be controlled so as not to cause an overcurrent.

  In the present invention, the type, shape, arrangement, number, and the like of the members are not limited to the above-described embodiment, and the gist of the invention is appropriately replaced such that the constituent elements are appropriately replaced with those having the same operational effects. Of course, it can be changed as appropriate without departing from the scope.

  As described above, in the present invention, since the circuit that changes overcurrent into heat can be eliminated by adopting a configuration that does not generate overcurrent, the cost of the product can be reduced and the apparatus can be reduced. An LED lamp lighting device that can be reduced in size can be provided, and is expected to be widely applicable to LED lamp lighting devices such as motorcycles because of its universality.

DESCRIPTION OF SYMBOLS 1 ... LED lamp lighting device 2 ... LED lamp lighting device 10 ... LED lamp drive control part 11 ... Booster circuit 12 ... Drive control part 13 ... Lamp circuit 14 ... Lamp circuit 15 ... Switch 16 ... Bypass circuit 20 ... LED lamp drive control part DESCRIPTION OF SYMBOLS 21 ... Power supply part 22 ... Drive control part 121 ... Voltage monitoring part 122 ... Boost control part 123 ... Gate control part 124 ... Protection circuit 221 ... Voltage monitoring part 222 ... Boost control part

Claims (5)

An LED lamp lighting device for driving an LED lamp,
A first lamp circuit comprising one LED lamp or a plurality of LED lamps connected in series;
A second lamp circuit connected in series to the first lamp circuit and comprising one LED lamp or a plurality of LED lamps connected in series;
An LED lamp drive control unit that drives the first lamp circuit and the second lamp circuit by receiving a current supply from a power supply unit;
A bypass circuit to which a current is supplied from the LED lamp drive control unit when the LED lamp drive control unit cannot supply a current to the second lamp circuit due to an abnormality;
A switch that can be switched to a connection state that bypasses the second lamp circuit from the power supply unit and supplies current to the first lamp circuit and the bypass circuit when the abnormality occurs. ,
The LED lamp drive controller is
When the switch is in the connected state, an applied voltage applied to the first lamp circuit is set to a driving voltage applied to the first lamp circuit to drive the first lamp circuit at a constant current. Lower,
An LED lamp lighting device characterized by that. The LED lamp drive controller is
When the switch is in the connected state, the current supplied to the first lamp circuit after the applied voltage is lowered below the drive voltage, the target when the first lamp circuit is driven at a constant current The LED lamp lighting device according to claim 1, wherein the applied voltage is boosted to a value. The LED lamp drive controller is
When the switch is in the connection state, the applied voltage is lowered to a voltage at which the bypass circuit does not turn off and a voltage that can supply a current that does not cause an overcurrent to the first lamp circuit. The LED lamp lighting device according to claim 1 or 2. The LED drive controller is
A booster circuit for boosting the applied voltage;
A protection circuit comprising a switching element connected between the booster circuit and the first lamp circuit and the second lamp circuit, and a resistor connected in parallel with the switching element;
The LED lamp lighting device according to any one of claims 1 to 3, wherein a voltage on the booster circuit side of the protection circuit is detected as the applied voltage. The LED drive controller is
A booster circuit for boosting the applied voltage;
A protection circuit comprising a switching element connected between the booster circuit and the first lamp circuit and the second lamp circuit, and a resistor connected in parallel with the switching element;
4. The LED lamp lighting device according to claim 1, wherein a voltage on the first lamp circuit and the second lamp circuit side of the protection circuit is detected as the applied voltage. 5.

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