JP6812679B2 - Current control device, lighting device and current control method - Google Patents

Description

The present invention relates to a current control device, a lighting device and a current control method.

Conventionally, there is a current control device that supplies electric power, particularly a desired current, to an analog element such as a light emitting element to operate it. When this current control device operates an analog element using a power source such as a battery, the required voltage may be higher or lower than the supply voltage of the power supply depending on the operating condition of the analog element. In such a case, there is known a technique of boosting the power supply voltage by a charge pump circuit to supply electric power as needed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-21314

However, in a current control device using such a limited power supply, while the voltage higher than the voltage required for the operation of the analog element is generated and the power is supplied, the power consumption related to the operation of the analog element is increased. In comparison, there is a problem that the power consumption of the current control device increases and the power efficiency decreases.

An object of the present invention is to provide a current control device, a lighting device, and a current control method capable of appropriately supplying electric power while further improving power efficiency.

In order to achieve the above object, the present invention
A charge pump circuit that selectively outputs one of several different output voltages, including a voltage higher than the input voltage, to supply the operating voltage of the analog element.
A current adjustment circuit that adjusts the current flowing through the analog element, and
The output voltage selected based on the operating voltage according to the current value of the current flowing through the analog element adjusted by the current adjusting circuit is output from the charge pump circuit, and is different for each of the plurality of output voltages. Based on the reference, a control unit that performs pulse modulation control according to the current flowing through the analog element and supplies power to the analog element.
Equipped with a,
The control unit determines that, for each of the plurality of output voltages, the power efficiency indicating the ratio of the power consumption of the analog element to the supply power related to the power supply to the analog element is passed to the analog element by the output voltage. The current control device is characterized in that the pulse modulation control is performed with the first current value that becomes the maximum within the specified current range as one reference .

According to the present invention, there is an effect that the current control device can appropriately supply electric power while improving the electric power efficiency.

It is a block diagram which shows the functional structure of the lighting apparatus of embodiment of this invention. It is a figure which shows the example of the relationship between the brightness (current value) of LED, and voltage. It is a flowchart which shows the control procedure of a lighting operation control process. It is a figure which shows the example of the relationship between the current value (luminance) of LED and the voltage corresponding to the temperature change. It is a flowchart which shows the modification of the control procedure of a lighting operation control process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a functional configuration of the lighting device 1 of the present embodiment.

The lighting device 1 includes a control unit 10, a dimming circuit 20, a charge pump circuit 30, a current adjusting circuit 40, an LED 50 (light emitting diode, a light emitting unit, an analog element), and a temperature measuring unit 60 (temperature measuring means). ) Etc. are provided.

The control unit 10 comprehensively controls the overall operation of the lighting device 1. The control unit 10 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a storage unit. These may be integrally arranged on an IC chip or a microcomputer. The control unit 10 receives power from the power supply unit and performs operation control based on a clock signal input from a signal generation unit such as an oscillation circuit or a frequency divider circuit. The control unit 10 is a charge pump circuit based on the brightness setting information acquired from the outside, the magnitude information of the adjustment voltage acquired from the current adjustment circuit 40, the ambient temperature data measured by the temperature measurement unit 60, and the like. By switching the presence / absence of charge pump operation in 30 and setting the presence / absence of PWM control in the current adjustment circuit 40 and the duty ratio during PWM control, an appropriate power supply (particularly current) can be supplied to the LED 50. Do.

The control unit 10 has an operation table 11 in the storage unit. The operation table 11 associates the charge pump operation switching conditions in the charge pump circuit 30 with each parameter such as the temperature data of the temperature measuring unit 60, the lighting time of the LED 50, and the magnitude of the input voltage Vin, and their combinations. Retain memory.

The dimming circuit 20 performs an adjustment operation of the constant current circuit 41 for obtaining a current amount corresponding to a set light emission amount based on a control signal from the control unit 10.

The charge pump circuit 30 selectively sets the power supplied from the power supply unit at the input voltage Vin according to the control of the control unit 10 as it is or the voltage boosted by the charge pump (boosting operation) as the output voltage Vout. Output to LED50. As the charge pump circuit 30, various well-known circuits can be used.
Here, a dry battery, a rechargeable battery, or the like is used as the power source for the electric power supplied from the power supply unit, but the input voltage is acquired from a commercial power source such as AC 100V and converted into a predetermined DC voltage by the power supply unit. It may be input as Vin.

The current adjusting circuit 40 sends a current adjusted according to the set light amount of the LED 50 to the LED 50 based on the input signals from the control unit 10 and the dimming circuit 20. The current adjusting circuit 40 includes a constant current circuit 41, a switching element 42, and the like. Various well-known circuits are used in the constant current circuit 41, and the current flowing through the constant current circuit 41, that is, the amount of current flowing through the LED 50 is changed (adjusted). Further, PWM (Pulse Width Modulation) operation (pulse modulation control) is performed by switching on / off of the switching element 42 at a predetermined frequency and duty ratio.

The LED 50 emits light by emitting light from the supply voltage input from the charge pump circuit 30 and the current determined by the current adjusting circuit 40. As the LED 50, an appropriate well-known LED 50 is selected according to the amount of light emitted and the color of light emitted. If there is no change in conditions such as temperature, the LED 50 emits light with a brightness (luminous flux) substantially proportional to the amount of flowing current.

The temperature measuring unit 60 measures the temperature of the operating environment of the lighting device 1, here the ambient temperature, and digitally outputs the control result to the control unit 10 at a predetermined sampling frequency.
Of these configurations, the current control device 2 is configured by each component except the LED 50 as an analog element.
Further, the temperature measuring unit 60 and the control unit 10 constitute an operating environment information acquisition means.

Next, the brightness control operation in the lighting device 1 of the present embodiment will be described.
In the lighting device 1 of the present embodiment, the brightness of the LED 50 is adjusted by adjusting the amount of current flowing through the constant current circuit 41 of the current adjusting circuit 40, and PWM control by on / off operation of the switching element 42 and adjustment of the duty ratio.

FIG. 2 is a diagram showing an example of the relationship between the brightness (current value) of the LED 50 and the voltage.
The LED 50 emits light with an output current If, that is, brightness, which increases as the applied voltage Vf increases due to an applied voltage Vf equal to or higher than a predetermined threshold voltage Vf0 (barrier voltage), although it varies depending on the material. As shown in FIG. 2A, in the LED 50, the applied voltage Vf increases as the brightness increases. The charge pump circuit 30 is equal to or higher than the operating voltage Va, which is the sum of the applied voltage Vf and the minimum adjustment voltage (minimum adjustment voltage Vcmin) related to the operation of the current adjustment circuit 40 such as the constant current circuit 41 and the switching element 42. It is necessary to output and supply the output voltage Vout. The minimum adjustment voltage Vcmin does not change significantly as the amount of current (luminance) increases. When the operating voltage Va becomes higher than the first output voltage Vout1 (first voltage) of the charge pump circuit 30 in a situation where the charge pump is not operated as the amount of current (brightness) increases, the charge pump is turned on. It becomes necessary to operate and output the second output voltage Vout2 (second voltage).

At this time, when the output voltage Vout is larger than the operating voltage Va, when the power corresponding to this voltage difference is consumed as heat by the resistance element of the constant current circuit 41 or the like, the supply power of the lighting device 1, that is, the operating voltage Va The power consumption of the LED 50 with respect to the product of the output current If, that is, the power efficiency indicating the ratio of the product of the applied voltage Vf and the output current If is reduced. In the lighting device 1 of the present embodiment, the output voltage Vout and the corresponding output current Iout are fixed to a value having high power efficiency, and the output time is PWM-controlled according to the brightness, so that the current flowing through the LED 50 The average current value of is changed within a predetermined current range.

As described above, there are two types of output voltage Vout, a first output voltage Vout1 and a second output voltage Vout2. When the operating voltage Va is equal to or less than the first output voltage Vout1, the first output voltage Vout1 is used. PWM control is performed by fixing it as the output voltage Vout, and when the operating voltage Va is larger than the first output voltage Vout1 (second output voltage Vout2 or less), the second output voltage Vout2 is fixed as the output voltage Vout and PWM control is performed. I do. As a result, as shown in FIG. 2B, the output voltage Vout is not increased more than necessary, and the difference between the output voltage Vout and the operating voltage Va is limited to a small state. Therefore, in the lighting device 1, it is not necessary to generate heat and consume the voltage difference between the output voltage Vout and the operating voltage Va as the average current value decreases.
That is, the brightness (average brightness) of the LED 50 relates to the brightness at the threshold current Is (first current value), which is the output current Iout corresponding to the first output voltage Vout1, and the PWM control in the situation where the charge pump is not operated. It is determined by the duty ratio, and in the situation where the charge pump is operated, it depends on the brightness at the current value Imax (second current value), which is the output current Iout corresponding to the second output voltage Vout2, and the duty ratio related to PWM control. It is decided.
In this way, with respect to the two-stage output voltage, the positions of the operating voltage Va (= first output voltage Vout1) and the threshold current Is, which have the highest power efficiency in the operation of the LED 50 on the low voltage side where the charge pump operation is not performed, are the relevant. This is the switching position for the two-step PWM control reference (that is, the amount of current for which the duty ratio is calculated).

For example, the forward current (absolute maximum rating) of the LED 50 is used as the current value Imax, but the brightness control range of the LED 50 is sufficiently larger than the brightness corresponding to this forward current as compared with the second output voltage Vout2. In the case of limiting to a low range, the absolute maximum rating of the pulse forward current may be used. Alternatively, the current value may be smaller than the value according to these absolute maximum standards according to the upper limit of the brightness control range, but the voltage difference between the operating voltage Va and the second output voltage Vout2 may not be large. preferable.
Here, the minimum current value in the current range that can be output by the lighting device 1 is set to zero, and the brightness can be adjusted at predetermined intervals or continuously up to the minimum current value.

FIG. 3 is a flowchart showing a control procedure by the control unit 10 of the lighting operation control process executed in the lighting device 1 of the present embodiment.
When the lighting operation control process is started, the control unit 10 (CPU) acquires the brightness setting signal from the outside (step S111). This signal may be a control signal from an external device or an operation reception signal by a user's input operation. The control unit 10 converts the output current If (average current value by PWM) of the LED 50 and the applied voltage Vf according to the acquired luminance setting (light intensity) (step S112). This conversion is not particularly limited, but may be performed with reference to the operation table 11.

The control unit 10 acquires the adjustment voltage Vc from the current adjustment circuit 40, and calculates the operating voltage Va together with the applied voltage Vf (step S113). The control unit 10 determines whether or not the operating voltage Va is equal to or less than the first output voltage Vout1 of the charge pump circuit 30 (step S114).

When it is determined that the operating voltage Va is equal to or less than the first output voltage Vout1 (“YES” in step S114), the control unit 10 sets the charge pump operation to off and outputs a control signal to the charge pump circuit 30. , The output voltage Vout is set to the first output voltage Vout1, and the output current Iout is set to the threshold current Is (step S115). Then, the process of the control unit 10 shifts to step S117.

When it is determined that the operating voltage Va is not equal to or less than the first output voltage Vout1 (greater than the first output voltage Vout1) (“NO” in step S114), the control unit 10 sets the charge pump operation on. A control signal is output to the charge pump circuit 30, and the output voltage Vout is set to the second output voltage Vout2 and the output current Iout is set to the current value Imax (step S116). Then, the process of the control unit 10 shifts to step S117.
The processing of steps S113 to S116 constitutes the voltage setting step.

When the process proceeds to step S117, the control unit 10 calculates the duty ratio of the PWM operation by the switching element 42 of the current adjustment circuit 40 based on the output of the charge pump circuit 30 and the setting according to the brightness (step). S117). The control unit 10 sets the output current Iout in the dimming circuit 20 and sets and operates the constant current circuit 41 so that the output current can be obtained (step S118). Further, the control unit 10 performs PWM control of the current adjustment circuit 40 by switching the switching element 42 on and off according to the calculated duty ratio (step S119).
The processing of steps S117 to S119 constitutes the current control step.
Then, the process of the control unit 10 returns to step S111. Even if there is no change in the content of the brightness setting signal, the applied voltage Vf and the output current If according to the operating state of the LED 50 and the current adjusting circuit 40, for example, the temperature change according to the continuous operation time and the amount of light emitted at that time. Since the relationship with the above can be corrected and the adjustment voltage Vc is changed at any time and returned, each process from step S111 is periodically repeated.

The first output voltage Vout1 to be compared with the above-mentioned operating voltage Va is not strictly set to this value, but may be a low voltage value including some margin. As shown in the modified example described later, the applied voltage Vf with respect to the current value flowing through the LED 50 can fluctuate, and the first output voltage Vout1 can also change due to the fluctuation of the input voltage Vin. Therefore, even if these fluctuations occur temporarily, a low voltage value is set so that the operating voltage Va becomes the first output voltage Vout1 or less with a sufficient probability according to the reliability of the lighting device 1 and the like. A current value smaller than the threshold current Is is intermittently flowed to the LED 50 by PWM control according to the lower voltage value. In other words, the output current (average current value by PWM control) when the charge pump operation is not performed can be appropriately determined in advance within a range smaller than the threshold current Is.

[Modification example]
Next, a modified example of the brightness control operation of the lighting device 1 will be described.
The relationship between the current value (that is, the brightness) flowing through the LED 50 and the applied voltage Vf varies greatly depending on the element of the LED 50, and further changes according to the state of the surrounding environment such as the ambient temperature.
FIG. 4 is a diagram showing an example of the relationship between the current value (luminance) and the voltage of the LED 50 according to the temperature change.

When the ambient temperature T rises from the predetermined standard temperature T0 to a temperature T1 higher than this, the applied voltage Vf (forward voltage) corresponding to the predetermined current value decreases, and the operating voltage also becomes Va (T0) accordingly. Decreases from to Va (T1). Therefore, the current when the first output voltage Vout1 and the operating voltage Va become equal, that is, the threshold current Is increases.

Further, since the input voltage Vin from a battery such as a dry battery or a rechargeable battery decreases according to the remaining battery level, the output voltage Vout of the charge pump circuit 30 also changes as the input voltage Vin decreases (changes). Therefore, this change in the output voltage Vout can also be a factor for changing the reference for switching the presence or absence of the charge pump operation.

In the lighting device 1 of the present embodiment, the threshold current Is is stored in the operation table 11 in association with parameters such as temperature conditions as a reference for switching the presence or absence of charge pump operation. The parameters (operating environment information) may include the ambient temperature measured by the temperature measuring unit 60, the input voltage Vin, and the duration after the start of the lighting operation. Then, a part or all of these parameters are acquired at an appropriate frequency, and the presence / absence of charge pump operation and the reference for PWM control are changed (changed) in the setting of the threshold current Is according to the acquired data (acquired data). Is switched.

FIG. 5 is a flowchart showing a modified example of the control procedure by the control unit 10 of the lighting operation control process executed in the lighting device 1 of the present embodiment.
In the lighting operation control processing of this modification, as compared with the lighting operation control processing shown in FIG. 3, the processing of steps S121 and S122 is added instead of the processing of step S113, and the processing of steps S112 and S114 to S116 The processing is replaced with the processing of steps S112a and S114a to S116a, respectively. Other processes are the same, and the same processing contents are designated by the same reference numerals and detailed description thereof will be omitted.

When the brightness setting is acquired in the process of step S111, the control unit 10 converts the output current If (average current value by PWM) according to the brightness (step S112a). The control unit 10 acquires the adjustment voltage Vc from the current adjustment circuit 40, acquires the ambient temperature from the temperature measurement unit 60 as a parameter, and measures and acquires the input voltage Vin (step S121).

The control unit 10 acquires and sets the threshold current Is according to the parameters such as the acquired adjustment voltage Vc, input voltage Vin, and ambient temperature T with reference to the operation table 11 (step S122).

The control unit 10 determines whether or not the output current If (average current value) to be passed through the LED 50 is equal to or less than the obtained threshold current Is or less under the control of the current adjustment circuit 40 (step S114a). When it is determined that the output current If is equal to or less than the threshold current Is (“YES” in step S114a), the control unit 10 sets the charge pump operation by the charge pump circuit 30 to off, and the current adjustment circuit 40 sets the charge pump operation to off. The current value of the output current Iout during the period in which the current flows by PWM control is set to the threshold current Is (step S115a). Then, the process of the control unit 10 shifts to step S117.

When it is determined that the output current If is not equal to or less than the threshold current Is (“NO” in step S114a), the control unit 10 sets the charge pump operation by the charge pump circuit 30 to ON, and the current of the output current Iout. The value is set to the current value Imax (step S116a). Then, the process of the control unit 10 shifts to step S117.

As described above, the current control device 2 that controls the current of the LED 50, which is the analog element of the lighting device 1 of the present embodiment, selects one of a plurality of different output voltages Vout including a voltage higher than the input voltage Vin. According to the charge pump circuit 30 that outputs the operating voltage Va of the LED 50, the current adjusting circuit 40 that adjusts the output current If (average current value) flowing through the LED 50, and the current value of the output current Iout flowing through the LED 50. The output voltage Vout selected based on the operating voltage Va is output from the charge pump circuit 30, and PWM control is performed according to the output current If flowing through the LED 50 with different standards for each of the plurality of output voltages Vout (Vout1, Vout2). A control unit 10 for supplying power to the LED 50 is provided. In this way, by performing PWM control with reference to the threshold current Is and the current value Imax, which are the operating voltages Va with good power efficiency for the plurality of output voltages in the charge pump circuit 30, the power efficiency is not lowered. It is possible to output an appropriate current with little waste in a wide output current range. Further, as a result, it is not necessary to constantly output a voltage corresponding to the maximum output voltage, and a wide range of current can be supplied by effectively using a battery having a limited output voltage such as a dry battery or a rechargeable battery.

Further, the control unit 10 has determined that for each of the plurality of output voltages Vout1 and Vout2, the power efficiency indicating the ratio of the power consumption of the LED50 to the power supply related to the power supply to the LED50 is passed to the LED50 by the output voltage Vout. PWM control is performed using the first current value (threshold current Is, current value Imax), which is the maximum within the current range, as one reference. In this way, by performing PWM control based on the current and voltage having the maximum power efficiency, even when a current smaller than this is passed through the LED 50, the power efficiency is not significantly reduced in a wide range, so that the state of high power efficiency is wide. It can be maintained over a range.

Further, the current range defined for each of the plurality of output voltages Vout1 and Vout2 is defined so that the power efficiency becomes the maximum at the maximum current value in the current range, and the control unit 10 sets the maximum current value. As a reference for each of the output voltages of the above, power is supplied to the LED 50 by performing PWM control according to the current flowing through the LED 50.
As a result, current output can be performed while maintaining high power efficiency over the entire current range by PWM control that throttles this current based on the maximum current value in each current range, so it is easily appropriate for the entire current output target range. Control can be performed efficiently.

Further, the charge pump circuit 30 can output a first output voltage Vout1 that does not boost the input voltage Vin and a second output voltage Vout2 that boosts the input voltage Vin, and is a current adjusting circuit. 40 causes the charge pump circuit 30 to output the first output voltage Vout1 when a current within the current range of the minimum current value (zero) or more and the threshold current Is or less to be passed through the LED 50 by the first output voltage Vout1 is passed through the LED 50. Then, PWM control is performed to flow the current of the threshold current Is at a duty ratio based on the threshold current Is and the output current If (average current value) to be passed through the LED 50, and when a current larger than the threshold current Is is passed to the LED 50, the charge is charged. PWM control is performed by causing the pump circuit 30 to output the second output voltage Vout2 and passing a current with a current value of Imax at a duty ratio based on a predetermined current value Imax and a current flowing through the LED 50 according to the second output voltage Vout2. Do.
In this way, the output voltage is switched in two stages by the charge pump operation, and the charge pump operation is switched and PWMed at the position of the operating voltage Va corresponding to the threshold current Is, which has good power efficiency with respect to the output voltage Vout on the low voltage side. Since the reference current related to control is switched, efficient current output can be performed with a simple control operation.

The minimum current value is zero. By using PWM control in this way, it is possible to output a wide range of small currents stably and efficiently.

Further, the temperature measuring unit 60 is provided, and the control unit 10 has a function of measuring the input voltage Vin, and the control unit 10 changes the setting related to the threshold current Is based on these acquired data. In particular, the resistance value of the LED 50 to be output of current decreases due to a temperature rise or the like, so that current easily flows, and the input voltage from a battery such as a dry battery may change depending on the remaining amount of the battery or the like. Therefore, by determining an appropriate threshold current Is in consideration of these, it is possible to output an appropriate current more efficiently.

Further, since the temperature measuring unit 60 is provided, it is possible to more appropriately reflect the characteristic change due to the temperature of the LED 50 from the ambient temperature and the like.

The pulse modulation control is PWM control. By controlling the amount of light by switching only the duty ratio while keeping the clock frequency constant, it is possible to accurately control the change in the amount of light with simple processing.

Further, the LED 50 is used as an analog element. As described above, by passing a current through the current control device 2 of the present embodiment to the analog element whose light amount changes according to the current value, a simpler and more accurate current amount can be passed with a small loss. ..

Further, the lighting device 1 of the present embodiment includes the above-mentioned current control device 2 and the LED 50.
With such a lighting device 1, it is possible to easily perform a lighting operation with low power consumption and accurate brightness over a wide range of brightness. In particular, since an appropriate amount of light is output even when a battery such as a dry battery is used, it is possible to output at an appropriate brightness while improving the usable time of the battery in a portable lighting device or the like. You can. In particular, since the power consumption when the brightness is lowered can be reduced, when the product is used at a low brightness, it can be used for a longer time according to the brightness.

Further, by using the above-mentioned current control method, it is possible to perform an appropriate current output with less waste in a wide output current range without lowering the power efficiency. Further, as a result, it is not necessary to always output a voltage corresponding to the maximum output voltage, and an effective current supply can be performed by effectively utilizing a battery having a limited output voltage such as a dry battery or a rechargeable battery.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, the pulse width control (PWM control) as the pulse modulation control achieves both reduction of power consumption and stable brightness adjustment, but in addition to PWM control, pulse frequency (PFM) control Etc. may be performed or combined.

Further, in the above embodiment, the charge pump circuit 30 is shown to boost the input voltage by one step, but the present invention is not limited to this. A charge pump circuit capable of boosting in two or more steps may be used, and the magnification of the boost voltage with respect to the input voltage is appropriately determined. In this case, different threshold currents Is (k) corresponding to each of the output voltages Vout (k) (k = 1 to N-1) of the two or more stages (N stages) are applied so as to improve power efficiency. You just have to decide.

Further, in the above embodiment, the current (average current value) is adjusted by PWM control based on the maximum current that can be passed at each output voltage, but the present invention is not limited to this. When a small current flows with reference to a voltage slightly lower than the maximum current, the average current value is narrowed down by PWM control, and the variable resistance value is made smaller between the reference current and the maximum current than during PWM control. It may be made to emit light. On the contrary, when the brightness setting is very small, the pulse modulation control and the increase in the resistance value may be combined to reduce the current flowing through the LED 50.

Further, in the above embodiment, the case where the current (light amount) and the voltage change with a monotonous increase is shown, but when the voltage peak is in the middle as compared with the current increase, that is, the power efficiency is maximized. If the position is not the position of the maximum current value, the current at the peak position is used as the reference current, PWM control is performed for the current smaller than this, and the current and voltage are adjusted for the current larger than this by adjusting the constant current circuit 41. You may switch such as getting.

Further, in the above embodiment, the light emitting diode (LED) is used as the analog element through which the current flows, but other light emitting bodies (light emitting parts), for example, an organic light emitting diode (OLED) may be used. good. Further, the device that emits light from the light emitter is not limited to the lighting device, and may be used for other purposes such as a sensor. Further, in this case, the light emitting body is not limited to one that emits visible light, and may be one that emits infrared light or ultraviolet light. Further, the current control device 2 may control the current for operating an analog element other than the light emitting body. For example, the analog element may be an electric heater, a motor, various sound generators, or the like.

Further, in the above embodiment, the case where power is supplied to a single LED has been described as an example, but a plurality of LEDs and the like are arranged in parallel so that the current flows substantially evenly through the resistance element and the like. It may be provided in. Alternatively, the same current may be controlled to flow completely individually for the plurality of LEDs by using the current control circuit.
In addition, specific details such as the configuration, control contents, and procedures shown in the above-described embodiment can be appropriately changed without departing from the spirit of the present invention.

Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and the equivalent scope thereof.
The inventions described in the claims originally attached to the application of this application are added below. The claims in the appendix are as specified in the claims originally attached to the application for this application.

[Additional Notes]
<Claim 1>
A charge pump circuit that selectively outputs one of several different output voltages, including a voltage higher than the input voltage, to supply the operating voltage of the analog element.
A current adjustment circuit that adjusts the current flowing through the analog element, and
The output voltage selected based on the operating voltage according to the current value of the current flowing through the analog element adjusted by the current adjusting circuit is output from the charge pump circuit, and is different for each of the plurality of output voltages. Based on the reference, a control unit that performs pulse modulation control according to the current flowing through the analog element and supplies power to the analog element.
A current control device characterized by comprising.
<Claim 2>
The control unit determines that, for each of the plurality of output voltages, the power efficiency indicating the ratio of the power consumption of the analog element to the supply power related to the power supply to the analog element is passed to the analog element by the output voltage. The current control device according to claim 1, wherein the pulse modulation control is performed using the first current value that becomes the maximum within the obtained current range as one reference.
<Claim 3>
The current range defined for each of the plurality of output voltages is defined so that the maximum current value in the current range has the highest power efficiency.
The control unit is characterized in that power is supplied to the analog element by performing the pulse modulation control according to the current flowing through the analog element, using the maximum current value as a reference for each of the plurality of output voltages. 2. The current control device according to claim 2.
<Claim 4>
The charge pump circuit can output a first voltage that does not perform a boosting operation with respect to the input voltage and a second voltage that performs a boosting operation from the input voltage.
The control unit
When a current within the current range equal to or greater than the minimum current value to be passed through the analog element by the first voltage and equal to or lower than the first current value is passed through the analog element, the first voltage is output to the charge pump circuit. Then, the pulse modulation control for passing the current of the first current value is performed with a duty ratio based on the first current value and the current flowing through the analog element.
When a current larger than the first current value is passed through the analog element, the charge pump circuit is made to output the second voltage, and a second current predetermined according to the second voltage is generated. The current control device according to claim 3, wherein the pulse modulation control for flowing the current of the second current value is performed by a duty ratio based on the value and the current flowing through the analog element.
<Claim 5>
The current control device according to claim 4, wherein the minimum current value is zero.
<Claim 6>
Equipped with operating environment information acquisition means
The current control device according to any one of claims 2 to 5, wherein the control unit changes the setting related to the first current value based on the acquired data of the operating environment information acquisition means. ..
<Claim 7>
The current control device according to claim 6, wherein the operating environment information acquisition means includes a temperature measuring means.
<Claim 8>
The current control device according to any one of claims 1 to 7, wherein the pulse modulation control is PWM control.
<Claim 9>
The current control device according to any one of claims 1 to 8, wherein the analog element is a light emitting diode.
<Claim 10>
The current control device according to claim 9 and
The light emitting part to which the output voltage is supplied and the current flows,
A lighting device characterized by being provided with.
<Claim 11>
A current adjustment circuit that adjusts the current flowing through the analog element, and a charge pump circuit that selectively outputs one of a plurality of different output voltages including a voltage higher than the input voltage to supply the operating voltage of the analog element. A current control method for a current control device comprising,
A voltage setting step of outputting the output voltage selected based on the operating voltage according to the current value of the current flowing through the analog element from the charge pump circuit.
A current control step in which pulse modulation control is performed according to a current flowing through the analog element based on a different reference for each of the plurality of output voltages, and power is supplied to the analog element.
A current control method comprising.

1 Lighting device 2 Current control device 10 Control unit 11 Operation table 20 Dimming circuit 30 Charge pump circuit 40 Current adjustment circuit 41 Constant current circuit 42 Switching element 50 LED (light emitting diode)
60 Temperature measuring unit Is threshold current Va Operating voltage Vc Adjustment voltage Vf Applied voltage Vin Input voltage Vout Output voltage

Claims (10)

A charge pump circuit that selectively outputs one of several different output voltages, including a voltage higher than the input voltage, to supply the operating voltage of the analog element.
A current adjustment circuit that adjusts the current flowing through the analog element, and
The output voltage selected based on the operating voltage according to the current value of the current flowing through the analog element adjusted by the current adjusting circuit is output from the charge pump circuit, and is different for each of the plurality of output voltages. Based on the reference, a control unit that performs pulse modulation control according to the current flowing through the analog element and supplies power to the analog element.
Equipped with a,
The control unit determines that, for each of the plurality of output voltages, the power efficiency indicating the ratio of the power consumption of the analog element to the supply power related to the power supply to the analog element is passed to the analog element by the output voltage. A current control device , each of which performs the pulse modulation control with the first current value that becomes the maximum within the specified current range as a reference . The current range defined for each of the plurality of output voltages is defined so that the maximum current value in the current range has the highest power efficiency.
The control unit is characterized in that power is supplied to the analog element by performing the pulse modulation control according to the current flowing through the analog element, using the maximum current value as a reference for each of the plurality of output voltages. The current control device according to claim 1 . The charge pump circuit can output a first voltage that does not perform a boosting operation with respect to the input voltage and a second voltage that performs a boosting operation from the input voltage.
The control unit
When a current within the current range equal to or greater than the minimum current value to be passed through the analog element by the first voltage and equal to or lower than the first current value is passed through the analog element, the first voltage is output to the charge pump circuit. Then, the pulse modulation control for passing the current of the first current value is performed with a duty ratio based on the first current value and the current flowing through the analog element.
When a current larger than the first current value is passed through the analog element, the charge pump circuit is made to output the second voltage, and a second current predetermined according to the second voltage is generated. The current control device according to claim 2, wherein the pulse modulation control for flowing the current of the second current value is performed with a duty ratio based on the value and the current flowing through the analog element. The current control device according to claim 3, wherein the minimum current value is zero. Equipped with operating environment information acquisition means
The current control device according to any one of claims 1 to 4 , wherein the control unit changes the setting related to the first current value based on the acquired data of the operating environment information acquisition means. .. The current control device according to claim 5 , wherein the operating environment information acquisition means includes a temperature measuring means. The current control device according to any one of claims 1 to 6 , wherein the pulse modulation control is PWM control. The current control device according to any one of claims 1 to 7 , wherein the analog element is a light emitting diode. The current control device according to claim 8 and
The light emitting part to which the output voltage is supplied and the current flows,
A lighting device characterized by being provided with. A current adjustment circuit that adjusts the current flowing through the analog element, and a charge pump circuit that selectively outputs one of a plurality of different output voltages including a voltage higher than the input voltage to supply the operating voltage of the analog element. A current control method for a current control device comprising,
A voltage setting step of outputting the output voltage selected based on the operating voltage corresponding to the current value of the current flowing through the analog element adjusted by the current adjusting circuit from the charge pump circuit.
A current control step in which pulse modulation control is performed according to a current flowing through the analog element based on a different reference for each of the plurality of output voltages, and power is supplied to the analog element.
For each of the plurality of output voltages, the power efficiency indicating the ratio of the power consumption of the analog element to the supply power related to the power supply to the analog element is within the current range defined to be passed through the analog element by the output voltage. With the first current value that becomes the maximum in 1 as a reference, the pulse modulation step that performs the pulse modulation control, respectively.
A current control method comprising.

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