Current control device and power supply system

Abstract

To provide a current control unit and a power supply system that can prevent the occurrence of an overcurrent in a DC load.SOLUTION: A current control unit 20 is inserted between a voltage control unit 10 and a DC load 50. Based on a DC voltage output from the voltage control unit 10, the current control unit 20 controls a DC current of a DC power output to the DC load 50 so that the DC current becomes a predetermined target current, and thereby outputs the DC power. Based on power from a power supply 40, the voltage control unit 10 controls the DC voltage so that the DC voltage becomes a predetermined target voltage, and thereby outputs the DC voltage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a current control device and a power supply system. [Background technology]

[0002] Patent Document 1 discloses a power supply device. The power supply device in Patent Document 1 is a switching power supply device, and includes an input section that receives an input voltage from an external device, a power supply section, and an output section. The power supply section generates a DC voltage from the voltage input through the input section and outputs the DC voltage from the output section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-88942 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the power supply device of Patent Document 1, the power supply unit controls the power supply voltage, which is the output voltage, to a specified voltage. Therefore, if the resistance value of the DC load changes during operation of the DC load, an overcurrent may occur in the DC load.

[0005] The present disclosure provides a current control device and a power supply system capable of preventing the occurrence of an overcurrent in a DC load. [Means for solving the problem]

[0006] A current control device according to an aspect of the present disclosure is inserted between a voltage control device and a DC load. The current control device outputs DC power by controlling a DC current of the DC power output to the DC load based on a DC voltage output from the voltage control device so that the DC current of the DC power becomes a predetermined target current.

[0007] A power supply system according to an embodiment of the present disclosure includes a voltage control device and at least one current control device. The voltage control device outputs a DC voltage by controlling a DC voltage based on power from a power supply so that the output DC voltage becomes a predetermined target voltage. The at least one current control device outputs DC power by controlling a DC current based on the DC voltage output from the voltage control device so that the DC current of the DC power output to a DC load becomes a predetermined target current. Effect of the Invention

[0008] According to the present disclosure, it is possible to prevent the occurrence of an overcurrent in a DC load. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a configuration example of a power supply system according to a first embodiment. [Diagram 2] 2 is a block diagram showing an example of the configuration of a voltage control device provided in the power supply system of FIG. 1. [Diagram 3] 2 is a circuit diagram showing an example of the configuration of a current control device included in the power supply system of FIG. 1. [Figure 4] 3 is a graph showing the relationship between current and voltage that satisfies the condition that the product of current and voltage is equal to the rated power of the voltage control device of FIG. 2. [Diagram 5] 4 is a graph showing a change in current with respect to voltage of a DC load connected to the current control device of FIG. 3. [Figure 6] 3 is a graph showing a change in current with respect to the voltage of a DC load directly connected to the voltage control device of FIG. 2. [Figure 7] FIG. 11 is a block diagram showing a configuration example of a power supply system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the inventor(s) provide the attached drawings and the following explanation so that those skilled in the art can fully understand the present disclosure, and do not intend for them to limit the subject matter described in the claims.

[0011] (Embodiment 1) [1-1. Overview] 1 is a block diagram showing an example of a configuration of a power supply system 1 according to embodiment 1. The power supply system 1 supplies DC power to a DC load 50 based on power from a power supply 40.

[0012] In Fig. 1, the power source 40 is, for example, a commercial AC power source. The power source 40 is not limited to an AC power source such as a commercial AC power source, and may be a DC power source. Examples of the DC power source include a solar cell, a fuel cell, and a storage battery. The power source 40 may be a power conditioner that selectively supplies power from an AC power source and a DC power source.

[0013] In FIG. 1, the DC load 50 operates by DC power. The DC load 50 has a characteristic that the resistance value of the DC load 50 changes when the DC load 50 operates. The DC load 50 is, for example, a laser diode. If the forward voltage of the laser diode is equal to or lower than the threshold voltage, almost no current flows through the laser diode. If the forward voltage of the laser diode exceeds the threshold voltage, a large current flows through the laser diode. Therefore, the resistance value of the laser diode when the forward voltage of the laser diode exceeds the threshold voltage is smaller than the resistance value of the laser diode when the forward voltage of the laser diode is equal to or lower than the threshold voltage. In this way, the laser diode has a characteristic that the resistance value changes when it operates. The DC load 50 is not limited to a laser diode, and may be a light-emitting diode. Further, examples of the DC load 50 include a sensor, a motor, and an electromagnetic valve.

[0014] As shown in Fig. 1, a power supply system 1 includes a voltage control device 10 and current control devices 20-1, ..., 20-N (hereinafter collectively referred to as "20"). The voltage control device 10 outputs a DC voltage by controlling a DC voltage based on power from a power supply 40 so that the output DC voltage becomes a predetermined target voltage. The current control device 20 outputs DC power by controlling a DC current based on the DC voltage output from the voltage control device 10 so that the DC current of the DC power output to a DC load 50 becomes a predetermined target current.

[0015] Since the power supply system 1 has the current control device 20 interposed between the voltage control device 10 and the DC load 50, it is a current source rather than a voltage source for the DC load 50. Therefore, even if the resistance value of the DC load 50 changes during operation of the DC load 50 and the DC current of the DC power supplied to the DC load 50 changes, the current control device 20 controls the DC current so that the DC current becomes a predetermined target current. Therefore, the power supply system 1 can reduce the possibility of an overcurrent occurring in the DC load 50.

[0016] [1-2.Details] Hereinafter, a detailed description will be given of the power supply system 1. As shown in Fig. 1, the power supply system 1 includes a voltage control device 10 and a plurality of current control devices 20-1, ..., 20-N, where N represents the number of current control devices 20.

[0017] [1-2-1. Configuration of voltage control device] In Fig. 1, a voltage control device 10 outputs a DC voltage by controlling a DC voltage based on power from a power source 40 so that the output DC voltage becomes a predetermined target voltage. The voltage control device 10 is a switching power supply for outputting a constant voltage. The voltage control device 10 is attached to an object such as a DIN rail. The connection between the voltage control device 10 and the power source 40 is not limited to an electric wire, but can be realized by an appropriate wiring method such as a conductive bar.

[0018] Fig. 2 is a block diagram showing a configuration example of the voltage control device 10. As shown in Fig. 2, the voltage control device 10 includes a rectifier circuit 11, a smoothing circuit 12, a switching circuit 13, a rectifier circuit 14, a smoothing circuit 15, a voltage detection circuit 16, and a control circuit 17.

[0019] The rectifier circuit 11 is configured to include, for example, a diode bridge. The rectifier circuit 11 rectifies the voltage from the power supply 40 and outputs the rectified voltage to the smoothing circuit 12.

[0020] The smoothing circuit 12 is configured to include, for example, a smoothing capacitor. The smoothing circuit 12 smoothes the voltage from the rectifier circuit 11 and outputs the smoothed voltage to the switching circuit 13.

[0021] The switching circuit 13 includes, for example, a transformer and a switching element. The primary winding and the switching element of the transformer are electrically connected in series between both ends of the smoothing capacitor of the smoothing circuit 12. The secondary winding of the transformer is connected to the rectifier circuit 14. The control circuit 17 outputs a PWM signal to the switching element of the switching circuit 13 to switch the voltage from the smoothing circuit 12 and apply a pulse voltage to the primary winding of the transformer. The secondary winding of the transformer outputs a pulse voltage to the rectifier circuit 14 that is lower than the pulse voltage input to the primary winding of the transformer.

[0022] The rectifier circuit 14 is configured to include, for example, a rectifier diode. The rectifier circuit 14 rectifies the pulse voltage from the secondary winding of the transformer of the switching circuit 13, and outputs the rectified voltage to the smoothing circuit 15.

[0023] The smoothing circuit 15 includes, for example, a smoothing capacitor. The smoothing circuit 15 smoothes the voltage from the rectifier circuit 14 and outputs a DC voltage.

[0024] The voltage detection circuit 16 detects the DC voltage output from the smoothing circuit 15, and outputs a voltage detection signal indicating the detected DC voltage to the control circuit 17.

[0025] The control circuit 17 controls the duty ratio of the PWM signal output to the switching element of the switching circuit 13 so that the DC voltage indicated by the voltage detection signal from the voltage detection circuit 16 becomes a predetermined target voltage.

[0026] The configuration of the voltage control device 10 may be the same as the configuration of a known switching power supply or other circuits that generate a constant voltage, and therefore a detailed description of the voltage control device 10 will be omitted.

[0027] [1-2-2. Configuration of current control device] In FIG. 1, a plurality of current control devices 20-1, ..., 20-N are electrically connected in parallel to a voltage control device 10 and receive a DC voltage from the voltage control device 10. Each of the plurality of current control devices 20-1, ..., 20-N is electrically connected to a DC load 50. Each current control device 20 outputs DC power by controlling a DC current based on the DC voltage output from the voltage control device 10 so that the DC current of the DC power output to the DC load 50 becomes a predetermined target current. The current control device 20 is a switching power supply for outputting a constant current. The current control device 20 is attached to an object such as a DIN rail. The connection between the current control device 20, the voltage control device 10, and the DC load 50 is not limited to an electric wire, but may be realized by an appropriate wiring method such as a conductive bar.

[0028] 3 is a circuit diagram showing a configuration example of the current control device 20. The current control device 20 includes a switching circuit 21, a current detection circuit 22, an adjustment circuit 23, and a control circuit 24, as shown in FIG.

[0029] The switching circuit 21 outputs DC power to a DC load 50 based on the DC voltage from the voltage control device 10. The switching circuit 21 is a step-down chopper including a switching element S1, a coil L1, and a diode D1.

[0030] The current detection circuit 22 detects the DC current of the DC power output to the DC load 50, and outputs a current detection signal indicating the detected DC current to the control circuit 24. The current detection circuit 22 includes a resistor R1 and an operational amplifier OP1 for current detection. The resistor R1 is electrically connected in series to the DC load 50. The non-inverting input terminal and the inverting input terminal of the operational amplifier OP1 are electrically connected to a first end and a second end of the resistor R1 via resistors R2 and R3, respectively. The non-inverting input terminal of the operational amplifier OP1 is electrically connected to the ground via a resistor R4. The inverting input terminal of the operational amplifier OP1 is electrically connected to the output terminal of the operational amplifier OP1 via a resistor R5. The current detection circuit 22 outputs a voltage corresponding to the current flowing through the resistor R1 as a current detection signal from the output terminal of the operational amplifier OP1.

[0031] The adjustment circuit 23 adjusts a predetermined target current of the current control device 20 and outputs a target signal indicating the predetermined target current to the control circuit 24. The adjustment circuit 23 includes a variable resistor VR1. One end of the variable resistor VR1 is electrically connected to the ground, and the other end of the variable resistor VR1 is electrically connected to the internal power supply Vcc via a resistor R6. A variable resistance value output terminal of the variable resistor VR1 is electrically connected to the control circuit 24 via a resistor R7. The variable resistance value of the variable resistor VR1 corresponds to the predetermined target current. The predetermined target current is adjusted by adjusting the variable resistance value of the variable resistor VR1. The adjustment circuit 23 outputs a voltage corresponding to the variable resistance value of the variable resistor VR1 as a target signal from the variable resistance value output terminal of the variable resistor VR1.

[0032] The control circuit 24 controls the switching circuit 21 so that the DC current of the DC power supplied from the current control device 20 to the DC load 50 becomes a predetermined target current adjusted by the adjustment circuit 23. The control circuit 24 includes a drive circuit 241, a comparator CP1, a photocoupler PC1, and a switch S2. The non-inverting input terminal of the comparator CP1 is electrically connected to the variable resistance terminal of the variable resistor VR1 via a resistor R7. The inverting input terminal of the comparator CP1 is electrically connected to the output terminal of the operational amplifier OP1 of the current detection circuit 22, and receives a current detection signal from the current detection circuit 22. The photodiode PD1 of the photocoupler PC1 is electrically connected to the switch S2. The phototransistor PT1 of the photocoupler PC1 is electrically connected between the non-inverting input terminal of the comparator CP1 and the ground. The switch S2 switches the photodiode PD1 between emitting and not emitting light in response to manual operation of the switch S2.

[0033] The driving circuit 241 outputs a PWM signal to the gate of the switching element S1 via the resistor R8 to drive the switching element S1. When the phototransistor PT1 is off, the non-inverting input terminal of the comparator CP1 receives a target signal from the adjustment circuit 23. The output terminal of the comparator CP1 outputs a voltage corresponding to the difference between the voltage of the target signal from the adjustment circuit 23 and the voltage of the current detection signal from the current detection circuit 22. The driving circuit 241 adjusts the duty ratio of the PWM signal output to the switching element S1 so that the voltage of the output terminal of the comparator CP1 becomes small. In this way, the control circuit 24 controls the switching circuit 21 so that the DC current of the DC power supplied from the switching circuit 21 becomes a predetermined target current. When the phototransistor PT1 is on, the non-inverting input terminal of the comparator CP1 is connected to ground via the phototransistor PT1, the voltage of the output terminal of the comparator CP1 becomes 0, and the driving circuit 241 does not drive the switching element S1.

[0034] Next, the rated power of the multiple current control devices 20-1, ..., 20-N will be described. In the power supply system 1 of Fig. 1, the rated power of the multiple current control devices 20-1, ..., 20-N is set based on the rated power of the voltage control device 10. The sum of the rated power of the multiple current control devices 20-1, ..., 20-N is equal to or less than the rated power of the voltage control device 10. In an ideal case where there is no power loss in the switching circuit 21 of the current control device 20, the rated voltages and predetermined target currents of the multiple current control devices 20-1, ..., 20-N can be set so that the sum of the rated power of the multiple current control devices 20-1, ..., 20-N matches the rated power of the voltage control device 10.

[0035] In the power supply system 1 configured as above, the predetermined target current of the current control device 20 can be set to a value equal to or lower than the maximum rated current of the DC load 50. In this case, the DC load 50 can be prevented from being destroyed.

[0036] In the power supply system 1 configured as above, the predetermined target current of the current control device 20 can be set to be larger than the rated current of the voltage control device 10. In this case, the current control device 20 can output to the DC load 50 a current larger than the current output by the voltage control device 10 to the DC load 50. This prevents a current shortage at the start of the DC load 50. This contributes to improving the start of the DC load 50, and improves the stability of the DC load 50 at the start of its operation. When the power supply system 1 includes a plurality of current control devices 20, the predetermined target current of at least one of the plurality of current control devices 20 can be set to be larger than the rated current of the voltage control device 10.

[0037] In the power supply system 1 configured as above, the rated voltage of the current control device 20 can be set to be equal to or higher than the operating voltage of the DC load 50. In this case, the stability of the DC load 50 at the start of operation can be improved.

[0038] Next, an example of a predetermined target current and a rated voltage for each of the multiple current control devices 20-1, ..., 20-N will be described with reference to Fig. 4. Fig. 4 is a graph showing a relationship between current and voltage that satisfies the condition that the product of the current and the voltage is equal to the rated power of the voltage control device 10. In Fig. 4, I 10 indicates the rated current of the voltage control device 10, and V 10 indicates a predetermined target voltage of the voltage control device 10. For example, I 10 is 10A, V 10 is 24V and the rated power of the voltage control device 10 is 240W.

[0039] For example, the rated voltages of the current control devices 20-1, ..., 20-N can be set so that the rated voltages of the current control devices 20-1, ..., 20-N are equal to each other. 20 If so, the sum of the predetermined target currents of the multiple current control devices 20-1, . . . , 20-N is I 20 Then, V 20 ×I 20 =V10 ×I 10 If the operating voltage of the DC load 50 is 3 V, then V 20 If is 3V, I 20 is 80 A. When the number N of current control devices 20 is 5, all of the predetermined target currents of the five current control devices 20-1, 20-2, 20-3, 20-4, and 20-5 are set to be equal to or higher than the rated current of the voltage control device 10. The DC currents of the five current control devices 20-1, 20-2, 20-3, 20-4, and 20-5 are, for example, 20 A, 18 A, 16 A, 14 A, and 12 A. At least one of the predetermined target currents of the five current control devices 20-1, 20-2, 20-3, 20-4, and 20-5 may be set so that the predetermined target current of at least one of the five current control devices 20-1, 20-2, 20-3, 20-4, and 20-5 is greater than the rated current of the voltage control device 10.

[0040] For example, the predetermined target currents of the current control devices 20-1, ..., 20-N can be set so that the predetermined target currents of the current control devices 20-1, ..., 20-N are equal to each other. 20 In this case, the sum of the rated voltages of the multiple current control devices 20-1, ..., 20-N is V 20 Then, V 20 ×I 20 =V 10 ×I 10 It is. 20 If is 12A, V 20 is 20 V. When the number N of current control devices 20 is 3, the rated voltages of the three current control devices 20-1, 20-2, and 20-3 are, for example, 10 V, 7 V, and 3 V, respectively.

[0041] For example, the predetermined target currents and rated voltages of the current control devices 20-1, ..., 20-N can be set so that the predetermined target currents of the current control devices 20-1, ..., 20-N are equal to each other, and the rated voltages of the current control devices 20-1, ..., 20-N are equal to each other. 30 , rated voltage V 30 Then, N×V30 ×I 30 =V 10 ×I 10 When the number N of the current control devices 20 is 5, for example, V 30 is 3V, I 30 is 16A.

[0042] For example, the predetermined target currents and rated voltages of the multiple current control devices 20-1, ..., 20-N can be set so that the predetermined target currents of the multiple current control devices 20-1, ..., 20-N are different from one another and the rated voltages of the multiple current control devices 20-1, ..., 20-N are different from one another. When the number N of current control devices 20 is 2, the predetermined target current of the current control device 20-1 can be set to I 41 , rated voltage V 41 The predetermined target current of the current control device 20-2 is I 42 , rated voltage V 42 Then, V 41 ×I 41 +V 42 ×I 42 =V 10 ×I 10 For example, I 41 is 24A,V 41 is 5V, I 42 is 20A,V 42 is 6V.

[0043] [1-2-3. Performance evaluation] In order to confirm that the power supply system 1 can prevent the occurrence of an overcurrent in the DC load 50, the relationship between the voltage applied to the DC load 50 and the current flowing through the DC load 50 was examined. Fig. 5 is a graph showing the change in the current flowing through the DC load 50 relative to the voltage applied to the DC load 50 when the DC load 50 is connected to the voltage control device 10 via the current control device 20. Fig. 6 is a graph showing the change in the current flowing through the DC load 50 relative to the voltage applied to the DC load 50 when the DC load 50 is connected to the voltage control device 10 instead of the current control device 20. In Figs. 5 and 6, V th indicates the threshold voltage of the DC load 50, and I r indicates the maximum rated current of DC load 50.

[0044] As can be seen from FIGS. 5 and 6, the voltage applied to the DC load 50 is equal to the threshold voltage V th In the following cases, the DC load 50 is in a state where almost no current flows through the DC load 50. This state is close to a state where the DC load 50 is not connected to the voltage control device 10 or the current control device 20.

[0045] On the other hand, the voltage applied to the DC load 50 is the threshold voltage V th 6, the voltage control device 10 controls the DC voltage output to the DC load 50, but does not control the current flowing through the DC load 50. Therefore, when the current flowing through the DC load 50 exceeds the maximum rated current I r In the case of FIG. 6, the load by the DC load 50 increases when the voltage across the DC load 50 exceeds the threshold voltage V th In this way, when the DC load 50 exceeds the threshold voltage V th In this case, when the voltage control device 10 is directly connected to the DC load 50 and the DC load 50 is operated by the voltage control device 10, the voltage applied to the DC load 50 becomes equal to or exceeds the threshold voltage V th The moment this voltage is exceeded, a large current will flow, which may damage the DC load 50.

[0046] In the case of FIG. 5, the current control device 20 controls the DC current of the DC power supplied to the DC load 50 to a predetermined target current I c Therefore, the current flowing through the DC load 50 is controlled to the maximum rated current I r The DC load 50 is a laser diode, a light-emitting diode, etc., and has a threshold voltage V th In order to prevent the DC load 50 from being damaged when the load has a current control device 20, the current source, it is necessary to supply DC power to the DC load 50. By supplying DC power to the DC load 50 from the current control device 20, the current source, the occurrence of an overcurrent in the DC load 50 can be prevented.

[0047] As is clear from the graphs shown in FIGS. 5 and 6, it was confirmed that the power supply system 1 can prevent the occurrence of an overcurrent in the DC load 50.

[0048] [1-3. Effects, etc.] As described above, in the present embodiment, the power supply system 1 includes the voltage control device 10 and a plurality of current control devices 20. The voltage control device 10 outputs a DC voltage by controlling a DC voltage based on the power from the power supply 40 so that the output DC voltage becomes a predetermined target voltage. Each of the plurality of current control devices 20 outputs DC power by controlling a DC current based on the DC voltage output from the voltage control device 10 so that the DC current of the DC power output to the DC load 50 becomes a predetermined target current.

[0049] As shown in FIG. 1, in the power supply system 1, the current control device 20 is inserted between the voltage control device 10 and the DC load 50. Therefore, even if the resistance value of the DC load 50 changes during the operation of the DC load 50 and the DC current of the DC power supplied to the DC load 50 changes, the current control device 20 controls the DC current so that the DC current becomes a predetermined target current. This allows the power supply system 1 to prevent the occurrence of an overcurrent in the DC load 50. In particular, even if the voltage control device 10 has already been installed, it is possible to construct the power supply system 1 by retrofitting the current control device 20 to the voltage control device 10 so that the current control device 20 is inserted between the voltage control device 10 and the DC load 50. In this way, in the power supply system 1, it is possible to simply attach the current control device 20 to the voltage control device 10. It is also possible to prepare one voltage control device 10 and use multiple current control devices 20. In this case, it is also possible to distribute current to multiple DC loads 50 by multiple current control devices 20.

[0050] In the present embodiment, the power supply system 1 includes a plurality of current control devices 20-1, ..., 20-N, and can supply DC power from the voltage control device 10 to a plurality of DC loads 50. In particular, each of the plurality of current control devices 20-1, ..., 20-N controls the DC current so that the DC current of the DC power output to the DC load 50 becomes a predetermined target current. Even if any of the plurality of DC loads 50 is short-circuited, the current flowing through the short-circuited DC load 50 does not exceed the predetermined target current. Therefore, it is possible to prevent the short-circuit of any of the plurality of DC loads 50 from affecting the remaining DC loads 50. Even if any of the plurality of DC loads 50 is short-circuited, it is possible to prevent the remaining DC loads 50 from being damaged or broken. Therefore, the operation of the power supply system 1 can be normally terminated in order to replace the short-circuited DC load 50, etc.

[0051] Moreover, in the present embodiment, the DC load 50 has a characteristic that the resistance value of the DC load 50 changes when the DC load 50 is in operation. According to this configuration, it is possible to prevent the occurrence of an overcurrent in the DC load 50 having a characteristic that the resistance value changes when the DC load 50 is in operation.

[0052] In this embodiment, the DC load 50 is a light emitting diode or a laser diode. This configuration makes it possible to prevent overcurrent from occurring in the light emitting diode or the laser diode.

[0053] Furthermore, in this embodiment, the predetermined target current of the current control device 20 is equal to or less than the maximum rated current of the DC load 50. With this configuration, the DC load 50 can be prevented from being destroyed.

[0054] In this embodiment, the rated voltage of the current control device 20 is equal to or lower than the DC voltage output from the voltage control device 10. In other words, the rated voltage of the current control device 20 is equal to or lower than a predetermined target voltage of the voltage control device 10. Furthermore, the rated voltage of the current control device 20 is equal to or higher than the operating voltage of the DC load 50. With this configuration, it is possible to improve the stability of the DC load 50 at the start of its operation.

[0055] In the present embodiment, the rated power of the current control device 20 is equal to or less than the rated power of the voltage control device 10. The predetermined target current of the current control device 20 is greater than the rated current of the voltage control device 10. With this configuration, it is possible to improve the stability of the DC load 50 at the start of its operation.

[0056] Moreover, in this embodiment, the power supply system 1 includes a plurality of current control devices 20. The sum of the rated powers of the plurality of current control devices 20 is equal to or less than the rated power of the voltage control device 10. The predetermined target current of at least one of the plurality of current control devices 20 is greater than the rated current of the voltage control device 10. With this configuration, it is possible to improve the stability of the DC load 50 at the start of its operation.

[0057] (Embodiment 2) 7 is a block diagram showing an example of the configuration of a power supply system 1A according to the second embodiment. The power supply system 1A includes a voltage control device 10, a plurality of current control devices 20-1, 20-2, 20-3, . . . , 20-N, and a distribution device 30.

[0058] 7, a distribution device 30 distributes a DC voltage from a voltage control device 10 to a plurality of current control devices 20. The distribution device 30 is configured with an input terminal electrically connected to the voltage control device 10 and a plurality of output terminals electrically connected to the plurality of current control devices 20, respectively. The distribution device 30 outputs the DC voltage received from the voltage control device 10 at the input terminal to each of the plurality of current control devices 20 from the plurality of output terminals.

[0059] 7, two current control devices 20-1 and 20-2 and a distribution device 30 are directly connected to a voltage control device 10, and the remaining current control devices 20-3, ..., 20-N are connected to the distribution device 30. The current control device 20 does not necessarily have to be directly connected to the voltage control device 10, and may be indirectly connected to the voltage control device 10 via the distribution device 30.

[0060] The distribution device 30 may have a known configuration, and therefore a detailed description of the distribution device 30 will be omitted. The distribution device 30 is attached to an object such as a DIN rail. The connection between the distribution device 30 and the voltage control device 10 and the current control device 20 is realized by an appropriate wiring method such as a conductive bar, not limited to electric wires.

[0061] As described above, in the present embodiment, the power supply system 1A includes the distribution device 30, which distributes the DC voltage from the voltage control device 10 to the multiple current control devices 20. The distribution device 30 makes it possible to connect the multiple current control devices 20 in parallel to one output terminal of the voltage control device 10. By using the distribution device 30, it is possible to increase the number of current control devices 20 that can be connected to the voltage control device 10. This configuration makes it possible to improve the degree of freedom of wiring for connecting the multiple current control devices 20 to the voltage control device 10.

[0062] (Modification) The embodiments of the present disclosure are not limited to the first and second embodiments. As long as the object of the present disclosure can be achieved, various modifications of the first and second embodiments are possible depending on the design and the like. Modifications of the first and second embodiments are listed below. The modifications described below can be applied in appropriate combination.

[0063] In one modified example, the number of voltage control devices 10, the number of current control devices 20, and the number of distribution devices 30 are not particularly limited. The power supply system 1 only needs to include at least one voltage control device 10 and at least one current control device 20.

[0064] When the power supply system 1 includes one voltage control device 10 and one current control device 20, the rated power of the current control device 20 is set to be equal to or less than the rated power of the voltage control device 10. In an ideal case where there is no power loss in the switching circuit 21 of the current control device 20, the rated power of the current control device 20 can be set to match the rated power of the voltage control device 10.

[0065] Referring to FIG. 4, the predetermined target current of the current control device 20 is I20 , the rated voltage of the current control device 20 is V 20 Then, V 20 ×I 20 ≦V 10 ×I 10 So that V 20 and I 20 If the operating voltage of the DC load 50 is 3 V, V 20 Set to, for example, 3V, and I 20 can be set to, for example, 20A to 80A.

[0066] In this case, the predetermined target current of the current control device 20 can be set to 2 to 8 times the rated current of the voltage control device 10. In this way, the current control device 20 can output to the DC load 50 a current larger than the current output to the DC load 50 by the voltage control device 10. This makes it possible to prevent a current shortage at the start-up of the DC load 50. This contributes to improving the start-up of the DC load 50, and improves the stability of the DC load 50 at the start of its operation.

[0067] In one modified example, the voltage control device 10 may be connectable to a plurality of power sources 40 and may receive power from all or some of the plurality of power sources 40. The voltage control device 10 may have a noise filter, an inrush current limiting circuit, a harmonic current suppression circuit, an overvoltage protection circuit, and an overcurrent protection circuit as necessary. The noise filter, the inrush current limiting circuit, the harmonic current suppression circuit, the overvoltage protection circuit, and the overcurrent protection circuit may be of conventionally known configurations, and therefore detailed description thereof will be omitted.

[0068] In one modification, the current control device 20 may receive a DC voltage from one or more voltage control devices 10 and one or more distribution devices 30. The current control device 20 may supply DC power to each of a plurality of DC loads 50. The current control device 20 does not necessarily have to include the adjustment circuit 23. The circuit configuration of the switching circuit 21 and the current detection circuit 22 of the current control device 20 is not limited to the circuit configuration shown in Fig. 3 and may be a well-known circuit configuration.

[0069] (Aspect) As is clear from the first and second embodiments and the modified examples, the present disclosure includes the following aspects. In the following, reference symbols are given in parentheses only to clarify the correspondence with the first and second embodiments.

[0070] The first aspect is a current control device (20) inserted between a voltage control device (10) and a DC load (50). The current control device (20) is configured to output DC power by controlling the DC current of the DC power output to the DC load (50) based on the DC voltage output from the voltage control device (10) so that the DC current becomes a predetermined target current. According to this aspect, an overcurrent in the DC load (50) can be prevented.

[0071] The second aspect is a current control device (20) based on the first aspect. In the second aspect, the voltage control device (10) is configured to output a DC voltage by controlling the DC voltage based on power from a power source (40) so that the DC voltage becomes a predetermined target voltage. According to this aspect, an overcurrent in a DC load (50) can be prevented.

[0072] A third aspect is the current control device (20) based on the first or second aspect. In the third aspect, the DC load (50) has a characteristic that a resistance value of the DC load (50) changes when the DC load (50) is in operation. According to this aspect, it is possible to prevent the occurrence of an overcurrent in the DC load (50) having a characteristic that a resistance value changes when the DC load (50) is in operation.

[0073] A fourth aspect is a current control device (20) based on the third aspect. In the fourth aspect, the DC load (50) is a light-emitting diode or a laser diode. According to this aspect, it is possible to prevent the occurrence of an overcurrent in the light-emitting diode or the laser diode.

[0074] A fifth aspect is a current control device (20) based on any one of the first to fourth aspects. In the fifth aspect, the predetermined target current is equal to or less than a maximum rated current of the DC load (50). According to this aspect, it is possible to prevent the DC load (50) from being damaged.

[0075] A sixth aspect is a current control device (20) based on any one of the first to fifth aspects. In the sixth aspect, the rated voltage of the current control device (20) is equal to or lower than the DC voltage of the voltage control device (10) and is equal to or higher than the operating voltage of the DC load (50). According to this aspect, it is possible to improve stability at the start of operation of the DC load (50).

[0076] The seventh aspect is a current control device (20) based on any one of the first to sixth aspects. In the seventh aspect, the rated power of the current control device (20) is equal to or less than the rated power of the voltage control device (10). The predetermined target current of the current control device (20) is greater than the rated current of the voltage control device (10). According to this aspect, it is possible to improve stability at the start of operation of the DC load (50).

[0077] An eighth aspect is a power supply system (1;1A) including a voltage control device (10) and at least one current control device (20). The voltage control device (10) is configured to output a DC voltage by controlling a DC voltage based on power from a power source (40) so that the output DC voltage becomes a predetermined target voltage. The at least one current control device (20) is configured to output a DC power by controlling a DC current based on the DC voltage output from the voltage control device (10) so that the DC current of the DC power output to a DC load (50) becomes a predetermined target current. According to this aspect, it is possible to prevent an overcurrent from occurring in the DC load (50).

[0078] A ninth aspect is a power supply system (1; 1A) based on the eighth aspect. In the ninth aspect, the DC load (50) has a characteristic that a resistance value of the DC load (50) changes when the DC load (50) is in operation. According to this aspect, it is possible to prevent an overcurrent from occurring in the DC load (50) having a characteristic that a resistance value changes when the DC load (50) is in operation.

[0079] A tenth aspect is a power supply system (1; 1A) based on the ninth aspect. In the tenth aspect, the DC load (50) is a light-emitting diode or a laser diode. According to this aspect, it is possible to prevent the occurrence of an overcurrent in the light-emitting diode or the laser diode.

[0080] An eleventh aspect is a power supply system (1;1A) based on any one of the eighth to tenth aspects. In the eleventh aspect, the predetermined target current is equal to or less than a maximum rated current of the DC load (50). According to this aspect, it is possible to prevent damage to the DC load (50).

[0081] A twelfth aspect is a power supply system (1;1A) based on any one of the eighth to eleventh aspects. In the twelfth aspect, a rated voltage of the at least one current control device (20) is equal to or lower than the predetermined target voltage and equal to or higher than an operating voltage of the DC load (50). According to this aspect, it is possible to improve stability at the start of operation of the DC load (50).

[0082] A thirteenth aspect is a power supply system (1;1A) based on any one of the eighth to twelfth aspects. In the thirteenth aspect, the power supply system (1;1A) includes one of the current control devices (20). The rated power of the current control device (20) is equal to or less than the rated power of the voltage control device (10). The predetermined target current of the current control device (20) is greater than the rated current of the voltage control device (10). According to this aspect, it is possible to improve stability at the start of operation of the DC load (50).

[0083] A fourteenth aspect is a power supply system (1;1A) based on any one of the eighth to twelfth aspects. In the fourteenth aspect, the power supply system (1;1A) includes a plurality of the current control devices (20). A total of rated powers of the plurality of current control devices (20) is equal to or less than a rated power of the voltage control device (10). The predetermined target current of at least one of the plurality of current control devices (20) is greater than the rated current of the voltage control device (10). According to this aspect, it is possible to improve stability at the start of operation of the DC load (50).

[0084] As described above, the embodiment has been described as an example of the technology in the present disclosure. For this purpose, the attached drawings and detailed description have been provided. Therefore, among the components described in the attached drawings and detailed description, not only components essential for solving the problem but also components that are not essential for solving the problem in order to illustrate the above technology may be included. Therefore, just because those non-essential components are described in the attached drawings or detailed description, it should not be immediately recognized that those non-essential components are essential. In addition, since the above-mentioned embodiment is intended to illustrate the technology in the present disclosure, various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0085] The present disclosure is applicable to a current control device and a power supply system. In particular, the present disclosure is applicable to a current control device and a power supply system for supplying power to a DC load. [Explanation of symbols]

[0086] 1, 1A power system 10 Voltage control device 20 Current control device 40 Power supply 50 DC load

Claims

1. A current control device inserted between a voltage control device and a DC load, the current control device controls a DC current of a DC power output to a DC load based on a DC voltage output from the voltage control device so that the DC current of the DC power becomes a predetermined target current, thereby outputting the DC power; The rated power of the current control device is equal to or less than the rated power of the voltage control device, the predetermined target current of the current control device is greater than the rated current of the voltage control device; Current control device.

2. the voltage control device controls the DC voltage based on power from a power source so that the DC voltage becomes a predetermined target voltage, thereby outputting the DC voltage. The current control device of claim 1 .

3. The DC load has a characteristic that a resistance value of the DC load changes when the DC load is in operation.

3. A current control device according to claim 1 or 2.

4. The DC load is a light emitting diode or a laser diode.

4. The current control device of claim 3.

5. The predetermined target current is equal to or less than a maximum rated current of the DC load. The current control device according to any one of claims 1 to 4.

6. The rated voltage of the current control device is equal to or lower than the DC voltage of the voltage control device and is equal to or higher than the operating voltage of the DC load. A current control device according to any one of claims 1 to 5.

7. A voltage control device that outputs a DC voltage by controlling the DC voltage so that the output DC voltage becomes a predetermined target voltage based on power from a power source; a current control device that controls a DC current of a DC power output to a DC load based on the DC voltage output from the voltage control device so that the DC current of the DC power becomes a predetermined target current, thereby outputting the DC power; Equipped with The rated power of the current control device is equal to or less than the rated power of the voltage control device, the predetermined target current of the current control device is greater than the rated current of the voltage control device; Power supply system.

8. a voltage control device that controls a DC voltage based on power from a power source so that the DC voltage becomes a predetermined target voltage, thereby outputting the DC voltage; a plurality of current control devices that output the DC power by controlling the DC current of the DC power output to a DC load based on the DC voltage output from the voltage control device so that the DC current of the DC power becomes a predetermined target current; Equipped with a sum of the rated powers of the plurality of current control devices is equal to or less than a rated power of the voltage control device; the predetermined target current of at least one of the plurality of current control devices is greater than the rated current of the voltage control device; Power supply system.

9. The DC load has a characteristic that a resistance value of the DC load changes when the DC load is in operation.

9. The power supply system according to claim 7 or 8.

10. The DC load is a light emitting diode or a laser diode.

10. The power supply system of claim 9.

11. The predetermined target current is equal to or less than a maximum rated current of the DC load. The power supply system according to any one of claims 7 to 10.

12. The rated voltage of the current control device is equal to or lower than the predetermined target voltage and equal to or higher than the operating voltage of the DC load. The power supply system according to any one of claims 7 to 11.

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