JP5717058B2 - Integrated circuit, power supply device and lighting device - Google Patents

Description

  Embodiments described herein relate generally to an integrated circuit, a power supply device, and a lighting device.

  It is known that an LED lighting device with high circuit efficiency can be obtained by lighting a light emitting diode using a DC-DC converter (see, for example, Patent Document 1). The DC-DC converter described in Patent Document 1 includes a step-down chopper, and a secondary winding that is magnetically coupled thereto when an increasing current flows through an inductor (first inductor) via an on-state switch element. The voltage induced in the (second inductor) is fed back to continue the ON operation of the switch element. In addition, a resistance element R6 is inserted in series with the switching element for detecting an increased current, and a control circuit is added to turn off the switching element when the voltage drop of the resistance element R6 exceeds a preset threshold value. .

  Then, when the switching element is turned off when the increasing current exceeds a predetermined value, the electromagnetic energy accumulated in the first inductor is released, and the decreasing current passes through the diode 15 and the capacitor 9 at the output end. Then flow. When the decreasing current becomes zero, the switch element is turned on by the counter electromotive force generated in the secondary winding of the inductor. By repeating the above circuit operation, DC-DC conversion is performed by self-excited constant current control, and the light emitting diode is turned on.

  On the other hand, a wide gap semiconductor is a semiconductor having a large band gap. Wide bandgap semiconductor elements using semiconductors such as SiC (silicon carbide), GaN (gallium nitride), and diamond as semiconductor substrates are attracting attention as semiconductors that have the potential to significantly break the performance limits of Si power devices. In the field of high-frequency power devices, expectations for wide gap semiconductors are high. These wide band gap semiconductor elements generally have normally-on characteristics in which current flows when the gate voltage is zero (see, for example, Patent Document 2).

  Further, as representative semiconductor elements using wide band gap semiconductors, JFET (junction FET), SIT (electrostatic induction transistor), MESFET (metal-semiconductor-field-effect-transistor), HFET ( There are Heterojunction Field Effect Transistors), HEMTs (High Electron Mobility Transistors), and storage FETs. In order to reliably turn off a semiconductor element having normally-on characteristics (hereinafter referred to as a normally-on switch), a drive circuit for a negative gate voltage is required.

  Since the wide band gap semiconductor element has excellent characteristics as described above, a wide band gap semiconductor is used for the switching element of the LED lighting device, so that the high frequency operation of 10 MHz or more can be performed to significantly increase the device. Miniaturization can be expected.

Japanese Patent No. 4123886 JP 2007-006658 A

However, when the LED lighting device of the prior art is inserted in series with the switch element and impedance means such as a resistance element for detecting an increasing current flowing through the inductor, and the voltage drop of the impedance means reaches a preset threshold value In addition, a current feedback type feedback circuit composed of a control circuit for turning off the switching element is required. For this reason, there is a problem that not only the circuit configuration becomes complicated, but also there is a difficulty in miniaturization.
An object of this invention is to provide the integrated circuit, power supply device, and illuminating device which contribute to size reduction.

The integrated circuit of the embodiment is used for DC-DC conversion. The integrated circuit includes a switching element having a pair of main terminals and a control element, a current control element having a pair of main terminals and a control element, and a diode element having a pair of main terminals, the switching element, While comprising the serial connection body in which the main terminals of the current control element and the diode element are connected in series, the serial connection body is located on one end side of the serial connection body, and the switching element, A main terminal of at least one of the current control element and the diode element, the first external terminal connected to the main terminal not connected to the main terminal of another element, and the other end of the series connection body A main terminal of at least one of the switching element, the current control element and the diode element, and another element A second external terminal connected to the main terminal that is not connected to the main terminal, and a connection point between at least any two of the main terminals of the switching element, the current control element, and the diode element. 3 external terminals, a fourth external terminal derived from the control terminal of the switching element, and a fifth external terminal derived from the control terminal of the constant current element.

  According to the present invention, miniaturization of an integrated circuit, a power supply device, and a lighting device can be expected.

FIG. 3 is a circuit diagram relating to the first embodiment. It is a circuit diagram regarding the second embodiment. Similarly, it is the electric current and voltage waveform figure of each part. It is a circuit diagram regarding the third embodiment. It is a circuit diagram regarding the fourth embodiment. It is a schematic diagram of the integrated circuit module regarding 5th Embodiment. FIG. 2 is a schematic partially enlarged and partially sectional perspective view of the planar coil structure.

  Hereinafter, embodiments of the present invention will be described in detail.

  (First Embodiment) An integrated circuit according to a first embodiment includes a switching element having a pair of main terminals and a control element, a current control element having a pair of main terminals and a control element, and a pair of main terminals. A switching element, a current control element, and a serial connection body in which the main terminals of the diode element are connected in series, and the serial connection body of the series connection body. A first external terminal that is located on one end side and is connected to the main terminal that is at least one of the switching element, the current control element, and the diode element and is not connected to the main terminal of another element A terminal and at least one of the switching element, the current control element, and the diode element, located on the other end side of the series connection body; A second external terminal connected to the main terminal that is not connected to the main terminal of another element, and at least any two of the switching element, the current control element, and the diode element. A third external terminal derived from a connection point between the terminals, a fourth external terminal derived from the control terminal of the switching element, and a fifth external terminal derived from the control terminal of the constant current element; It is characterized by comprising.

  (Second Embodiment) The integrated circuit of the second embodiment is the same as the integrated circuit of the first embodiment, in which at least one of the switching element, the current control element, and the diode element is GaN (gallium nitride). ) Is used.

(Third Embodiment) A power supply apparatus according to a third embodiment includes the integrated circuit of the first or second embodiment, an inductor connected to a third external terminal of the integrated circuit, and the inductor And a drive winding that is magnetically coupled and connected to a fourth external terminal of the integrated circuit.
(Fourth Embodiment) An illumination device according to a fourth embodiment includes the power supply device according to the third embodiment and a light emitting element to which power is supplied from the power supply device.

  In the embodiment of the present invention, the “chopper” is a concept including various choppers such as a step-down chopper, a step-up chopper, and a step-up / step-down chopper. The step-up / step-down chopper is obtained by sequentially connecting a step-up chopper and a step-down chopper. In each of the above choppers, an increase current flows from the DC power source to the inductor by turning on the switching element, and a decrease current flows through the diode by the electromagnetic energy accumulated in the inductor by turning off the switching element. Is common in that the DC power supply voltage is DC-DC converted and output to the output terminal.

  In the embodiment of the present invention, the switching element may be either a normally-on switch or a normally-off switch. When a wide bandgap semiconductor such as GaN-HEMT is used as the switching element, the switching characteristics at high frequency of MHz or higher, for example, 10 MHz or higher are remarkably improved, the switching loss is reduced, and the inductor is also downsized. Can be greatly reduced in size.

  In addition, in the case of a switching element using a wide band gap semiconductor, a device having a normally-on characteristic is easier to obtain and lower in cost, but a device having a normally-off characteristic is also possible. Also good. In addition, it is preferable to use a normally-on switching element having a negative switching threshold, because off control using a drive winding magnetically coupled to the inductor is facilitated.

  In the embodiment of the present invention, the constant current means as the current control element is a circuit means having a constant current characteristic, such as a constant current diode, a junction FET, a three-terminal regulator, and various constant current circuits using transistors. Can be used. The constant current circuit using a transistor is allowed to be a known constant current circuit using a monolithic or bilithic transistor. Moreover, GaN-HEMT which is a kind of junction FET can be used as a constant current means. Since the switching element as the constant current means is excellent in switching characteristics at a high frequency of 10 MHz or more, it is convenient for performing high-speed switching.

  In the embodiment of the present invention, the constant current means as the current control element is interposed in series with the switching element in the first circuit in which current flows through the inductor when the switching element is turned on. The constant current means is also interposed in the drive circuit for the switch element including the drive winding for driving the switching element. By having these configurations, the increasing current flowing through the constant current means reaches a constant current value, and when further increasing, the voltage of the constant current means rapidly increases. Due to the rise in voltage, the potential of the main terminal (eg, source) incorporated in the switching element drive circuit can be made relatively higher than the potential of the control terminal (eg, gate). As a result, since the potential of the control terminal becomes lower than the threshold value of the switching element, the switching element can be turned off. This circuit operation becomes easier and more reliable when the switching element is a normally-on switch and the threshold value is negative, but it is also effective for a normally-off switch.

  In the embodiment of the present invention, it is allowed to directly connect a switching element and a constant current means as a current control element in series. It becomes easy to integrate and integrate the current means. In this case, one main terminal of the switching element, for example, the drain, two terminals of the power system consisting of the main terminal on the other end side with respect to the switching element of the constant current means, and control of each of the switching element and the constant current means The switching element and the constant current means can be constituted by an IC module having a terminal structure, for example, two control system terminals composed of gates, so that the single component can be further miniaturized. be able to.

  In the embodiment of the present invention, the inductor stores electromagnetic energy therein when an increasing current flows from the DC power source to the first circuit via the switching element and the constant current means. Further, since the inductor releases the electromagnetic energy stored when the switching element is turned off, a current that decreases at that time flows to the second circuit.

  In the embodiment of the present invention, when the chopper is operated at a high frequency of 10 MHz or more, if the inductor and the drive winding magnetically coupled to the inductor have a planar coil structure and the capacitor has a planar structure, the integrated circuit of the chopper In addition, it is possible to obtain a highly reliable operation. In other words, a planar coil inductor and drive winding, a planar capacitor, a switching element, a constant current means, and a semiconductor chip on which semiconductor components such as a diode to be described later are stacked are integrated to be integrated as a whole. A circuit module can be constructed. As a result, the LED lighting device can be significantly reduced in size. Along with this, the distance between the drive coil and the switch is minimized, so that the generation of parasitic inductance and capacitance that are unnecessary and harmful to noise generation can be minimized, and the chopper operation. Improves stability and reliability.

In the embodiment of the present invention, the diode as the diode element provides a second circuit that is a path through which a decreasing current flows from the inductor. When a wide bandgap semiconductor, for example, a GaN-based diode is used as the diode, even higher speed switching is possible. In this case, it becomes easy to configure the diode as an integrated circuit of the semiconductor element together with the switching element and the constant current means. This integrated circuit has three main terminals of a power system comprising a main terminal at one end, a main terminal at the other end, and a main terminal at an intermediate connection point in a series connection body of a switching element, a constant current means and a diode. And it has a structure provided with five external terminals for convenience with two control terminals for controlling the switching element and the constant current means, respectively.
When the chopper is configured using the integrated circuit, the whole is further reduced in size and it becomes easy to perform high-speed switching.

  In the embodiment of the present invention, the drive winding is a winding magnetically coupled to the inductor and controls the switching element. That is, when the increasing current flowing in the inductor when the switching element is on reaches the constant current value of the constant current means and the switching element is turned off, a large voltage is generated, so the main terminal (source) of the switching element is controlled. Since it becomes higher than the terminal and the control terminal becomes relatively negative and falls below the threshold value, the switching element is maintained in the OFF state.

  (First Embodiment) The first embodiment will be described. A first embodiment is shown in FIG. The lighting device (LED lighting device) includes a DC power source DC, a chopper CH, and a load circuit LC.

  The DC power source DC is means for inputting a DC voltage before conversion to a chopper CH described later. Any configuration may be used as long as it outputs a DC voltage. For example, a rectifier circuit DB is mainly used, and a smoothing circuit including a smoothing capacitor can be provided as desired. In the present embodiment, the rectifier circuit DB is preferably a bridge-type rectifier circuit, and full-wave rectifies an AC voltage of an AC power supply AC, for example, a commercial AC power supply, to obtain a DC voltage.

  In the present embodiment, the chopper CH includes DC input terminals t1 and t2 and DC output terminals t3 and t4, and the inside is configured by any one of various known choppers such as a step-down chopper, a step-up chopper, and a step-up / step-down chopper. The chopper CH includes the switching element Q1, the constant current means CCM, the inductor L1, the diode D1, and the drive winding DW as common essential components in any of the above configurations.

  Switching element Q1 may be either a normally-off switch or a normally-on switch. The constant current means CCM may be of a type in which the constant current value is fixedly set in advance or may be variable. One end of the inductor L1 is connected to the drive winding DW. The drive winding DW is magnetically coupled to the inductor L1, induces a voltage proportional to the terminal voltage of the inductor L1, and drives the switching element Q1 by applying it to the control terminal of the switching element Q1.

  The chopper CH has a pair of input terminals t1 and t2 and a pair of output terminals t3 and t4, and the internal circuit can be divided into a first circuit and a second circuit in terms of circuit operation. The first circuit is a circuit that accumulates electromagnetic energy in the inductor L1 by flowing an increasing current from the DC power source DC. In the case of a step-down chopper, the switching element Q1, the constant current means, the inductor L1, and the load circuit LC are connected. The series circuit including is provided with the structure connected to DC power supply DC. When the switching element Q1 is turned on, an increasing current flows from the DC power source DC, and electromagnetic energy is accumulated in the inductor L1.

  The second circuit is a circuit that discharges electromagnetic energy accumulated in the inductor L1 and flows a current that decreases. In the case of a step-down chopper, a series circuit including a diode D1 and a load circuit LC described later is connected to the inductor L1. A current that decreases from the inductor L1 flows when the switching element Q1 is turned off.

  In the case of the step-up chopper, the chopper CH is a first circuit in which a series circuit of the inductor L1, the switching element Q1, and the constant current means CCM is connected to the DC power source DC, and a series circuit of the inductor L1, the diode D1, and the load circuit LC. Can be configured with a second circuit connected to the DC power source DC. The step-up / down chopper is as described above.

  The load circuit LC includes an output capacitor that includes a light emitting diode as a load and bypasses a high frequency component. In the case of a step-down chopper, the load circuit LC is located at a position on the circuit where both an increasing current and a decreasing current flow. It is connected. In the case of the step-up type, it is connected to a position on the circuit through which a decreasing current flows. The light-emitting diode LED is composed of a single forward current or a plurality of serially connected currents flowing through the output end of the chopper. Hereinafter, second to fifth embodiments for carrying out the present invention will be described with reference to FIGS. 2 to 7. In addition, in each figure, the same code | symbol is attached | subjected about the part same as FIG. 1, and description is abbreviate | omitted.

(Second Embodiment) A second embodiment will be described. A second embodiment is shown in FIG. In this embodiment, a GaN-HEMT is used for the switching element Q1, a constant current diode is used for the constant current means CCM, and an inductor L1 is connected between the constant current means CCM and the load circuit LC. In the figure, the same parts as those in FIG. Reference numeral C1 denotes a high frequency bypass capacitor connected between the input ends t1 and t2 of the chopper CH. Reference numeral C2 is a coupling capacitor inserted between the drive winding DW and the control terminal of the switching element Q1. Reference numeral A is a first circuit, and reference numeral B is a second circuit. Reference symbol LED of the load circuit LC is a light emitting diode and C3 is an output capacitor.
Next, the circuit operation in the second embodiment will be described with reference to FIG. 2 and FIG.

  When the DC power source DC is turned on, since the switching element Q1 of the chopper CH is turned on, a current flows from the DC power source DC through the switching element Q1 and the constant current means CCM in the first circuit A. Increases linearly. As a result, electromagnetic energy is accumulated in the inductor L1. Note that the gate-source voltage VGS of the switching element Q1 is 0 during the period when the switching element Q1 is on. When the increasing current reaches the constant current value of the constant current means CCM, the increasing tendency of the current is stopped and held at the constant current. Note that while the increasing current flows through the inductor L1, the terminal voltage of the inductor L1 is positive as shown in FIG.

  When the increasing current reaches the constant current value of the constant current means CCM, the current flowing through the inductor L1 tends to increase further, so that the voltage VCCM of the constant current means CCM is pulsed as shown in FIG. growing. Along with this, the source potential of the switching element Q1 becomes higher than the potential of the control terminal (gate), and as a result, the control terminal becomes relatively clearly a negative potential, so that the switching element Q1 is turned off. For this reason, the increasing current IU flowing into the inductor L1 is cut off when the switching element Q1 is turned off as shown in FIG.

  As soon as the switching element Q1 is turned off, the electromagnetic energy stored in the inductor L1 starts to be released, and a current that decreases as shown in FIG. While the decreasing current is flowing, the voltage polarity of the inductor L1 is reversed and becomes negative as shown in FIG. 3E, and the control terminal of the switching element Q1 is a negative potential in the drive winding DW. Since a negative voltage is applied between the gate and source of the switching element Q1 via the constant current means CCM as shown in FIG. 3 (f), the switching element Q1 is maintained in the OFF state. The

  When the decreasing current flowing through the second circuit becomes 0, the negative voltage applied to the control terminal of the switching element Q1 is not induced, and at the same time, the control terminal is shown in FIG. Since a positive voltage is induced in the drive winding DW, the switching element Q1 is turned on again, and thereafter the same circuit operation as described above is repeated.

  As is apparent from the above circuit operation, the chopper CH performs a step-down chopper operation, and an output current IO in which an increasing current and a decreasing current alternately flow in the load circuit LC connected between the output terminals t3 and t4 is obtained. It is formed as shown in FIG. 3 (d), and the light emitting diode LED is lit by these DC components, and the output capacitor C4 bypasses the high frequency component.

  (Third Embodiment) A third embodiment will be described. A third embodiment is shown in FIG. In the present embodiment, the constant current means CCM is a GaN-HEMT, and the inductor L1 is connected to a position where the load circuit LC is interposed between the constant current means CCM.

  Further, the constant current means CCM makes the constant current value variable by making the gate potential variable by using the adjustable potential source E. In the figure, reference symbol ZD1 denotes a diode for clamping the switching element Q1 so that the gate-source voltage VGS does not exceed 0.6V.

  Further, in the present embodiment, the switching element Q1, the constant current means CCM, and the diode D1 forming the series connection body are configured as an integrated circuit IC. The integrated circuit IC includes first to fifth external terminals P1 to P5. The first external terminal P1 is derived from the drain of the switching element Q1. The second external terminal P2 is derived from the cathode of the diode D1. The third external terminal P3 is derived from the connection point between the source of the constant current means CCM and the anode of the diode D1. The fourth external terminal P4 is derived from the gate of the switching element Q1. The fifth external terminal P5 is derived from the gate of the constant current means CCM.

  That is, in the integrated circuit IC, the first and second main terminals are derived from the main terminals of the semiconductor elements located at both ends of the series connection body composed of the three power semiconductor elements of the chopper, and the middle of the series connection body. The third external terminal is led out from the main terminal of the connection portion, and the fourth and fifth external terminals are led out from the control terminal of the switching element Q1 and the constant current means CCM. Therefore, the first to third external terminals are power systems, and the fourth and fifth external terminals are control systems.

  Thus, in the third embodiment, since the constant current means CCM is composed of a GaN-HEMT similarly to the switching element Q1, the high-speed switching characteristic at a high frequency of 10 MHz or more is further improved. However, if the diode D1 is also formed of a GaN substrate if desired, an integrated integrated circuit can be configured using a GaN substrate, and extremely high-speed switching can be achieved and a downsized chopper can be configured. Becomes easier.

  Further, since the constant current value is variable by using the adjustable potential source E1, it becomes easy to set a desired load current, and if the adjustable potential source E1 is feedback-controlled with respect to power supply voltage fluctuations. Further, it is possible to suppress the fluctuation of the light output of the light emitting diode with respect to the fluctuation of the power supply voltage. Further, the voltage drop of the constant current means CCM and the load circuit LC is added to the negative voltage of the drive winding DW applied to the control terminal of the switching element Q1.

  Further, if the switching element, the constant current means and the diode are configured as an integrated circuit having five external terminals, the entire chopper can be further miniaturized and high-speed switching can be easily performed.

  (Fourth Embodiment) A fourth embodiment will be described. A fourth embodiment is shown in FIG. Note that the same parts as those in FIG. In the present embodiment, the constant current means CCM is constituted by a current mirror constant current circuit using transistors Q2 and Q3. In the current mirror constant current circuit, the series circuit of the transistor Q2 and the resistor R1 is inserted in series with the switching element Q1, the base of the transistor Q3 is connected to the base of the transistor Q2, and the reverse bias power supply E2 is reverse polarity to the emitter. A DC power supply E3 is connected to a series circuit of a collector and a bias power supply E2. Further, the collector and base of the transistor Q3 are directly connected by a conductor.

  In addition, a pair of Zener diodes ZD1 and ZD2 are connected in parallel with opposite polarities between the control terminal of the switching element Q1 and the position across the constant current means CCM to form a clamp circuit. The Zener diode ZD1 has a Zener voltage of −12V, and the Zener diode ZD2 has a Zener voltage of + 0.7V, so that an excessive VGS is not applied to the switching element Q1.

  Thus, according to the fourth embodiment, the constant current value flowing through the transistor Q2 can be controlled as desired by the DC voltage connected to the transistor Q3, and the voltage generated when the constant current value is reached increases. There is no need to use the voltage of the light emitting diode LED of the load. Further, since the DC power source E2 is used to control the constant current means CCM constant current value, a transistor capable of high speed control is not required. Furthermore, if the constant current means CCM is turned off in synchronization when turning off the switching element Q1, the switching element Q1 can be substantially normally off. Furthermore, the semiconductor component parts of the switching element Q1, the constant current means CCM, and the diode D1 can be integrated on a GaN-based chip as desired.

(Fifth Embodiment) A fifth embodiment will be described. A fifth embodiment is shown in FIGS. This embodiment is an IC integrated in a part or a plurality of the first to fourth embodiments of the present invention, with the semiconductor components, coil components, capacitor components and external terminals of the LED lighting device being integrated. . That is, the remaining circuit components excluding the light emitting diode LED of the LED lighting device are composed of a planar coil structure L, a planar capacitor structure C, a GaN chip G, a wiring formation body W, a terminal formation body T, and a substrate structure B. Each planar structure is divided and formed, these planar structures are laminated together, and the structures are connected using means such as through holes to form an integrated circuit module IC ′. The integrated circuit module IC of the illustrated example is configured by the following planar structures.
As shown in FIG. 7, the planar coil structure L includes an inductor L1 and a drive winding DW.

Each of the flat coil wires is formed by winding in a plane to form a spiral shape, and is held so that they are in an appropriate separated state, and the inside and the periphery are covered with the magnetic layer M, and as a whole It is configured in a planar shape. One end of the inductor L1 and the drive winding DW is located at the center of the coil and constitutes a terminal portion t. Then, a through hole h is formed at the center of the terminal portion t, one terminal conductor of a constant current means portion of a GaN chip G described later is inserted into the through hole h, and a conductor is injected into the inside, The inductor L1, the drive winding DW, and the connection conductor of the GaN chip G are connected together. The magnetic layer M is made of, for example, ceramics or plastics in which ferrite fine particles are dispersed, as shown in a cross-sectional view in which a part of FIG.
The planar capacitor structure C is a planar structure in which a plurality of capacitors each including a pair of electrode bodies each sandwiching a thin dielectric film is assembled.
The GaN chip G is a planar structure in which a switching element Q1, a constant current means CCM, and a diode D1 are formed on a GaN-based semiconductor substrate.
The wiring formation body W is a planar structure that connects the planar coil structure L, the planar capacitor structure C, and the GaN chip G to the terminal formation body T described later as required.
The terminal forming body T is interposed between the wiring forming body W and a substrate structure B to be described later and connects the two.

  The board structure B includes an external terminal TE and external mounting means (not shown), and integrally supports the planar structures described above to form a module. The external terminal TE is an output terminal for connecting the input terminal of the LED lighting device and the light emitting diode LED.

  Thus, the present embodiment is suitable for an LED lighting device that operates at a high frequency of 10 MHz or higher, and the external terminals TE disposed on the substrate structure B are all DC, and only DC input / output is provided. Therefore, the operation is stable and a remarkable downsizing can be realized. For this reason, it becomes possible to arrange | position an LED lighting device between the light emitting diodes of an illuminating device, and it contributes to remarkable miniaturization of an illuminating device.

  Furthermore, the inductor and the drive winding have a planar coil structure, and an integrated circuit in which at least the switching element and the diode are stacked on at least one surface of the planar coil structure is configured. Since the generation of parasitic inductance and parasitic capacitance that are unnecessary and harmful to noise generation can be minimized, the stability and reliability of the chopper operation is improved.

  A ... first circuit, B ... second circuit, C1 ... high frequency bypass capacitor, C2 coupling capacitor, C3 ... output capacitor, CCM ... constant current means, CH ... chopper, D1 ... diode, DB ... rectifier circuit, DC ... DC power supply, DW ... drive winding, IC ... integrated circuit, L1 ... inductor, LC ... load circuit, LED ... light emitting diode, Q1 ... switching element, t1, t2 ... DC input terminal, t3, t4 ... DC output terminal

Claims (4)

An integrated circuit used for DC-DC conversion,
A switching element having a pair of main terminals and a control element;
A current control element having a pair of main terminals and a control element;
A diode element having a pair of main terminals, and including a series connection body in which the main terminals of the switching element, the current control element and the diode element are connected in series, and the series connection body,
Located on one end side of the series connection body and connected to the main terminal that is at least one of the switching element, the current control element, and the diode element and is not connected to the main terminal of another element A first external terminal that
The main terminal which is located on the other end side of the series connection body and is at least one of the switching element, the current control element and the diode element, and is not connected to the main terminal of another element; A second external terminal to be connected;
A third external terminal derived from a connection point between at least two main terminals of the switching element, the current control element, and the diode element;
A fourth external terminal derived from the control terminal of the switching element;
An integrated circuit comprising: a fifth external terminal derived from a control terminal of the constant current element.   2. The integrated circuit according to claim 1, wherein at least one of the switching element, the current control element, and the diode element uses GaN (gallium nitride). An integrated circuit according to claim 1 or 2, and
An inductor connected to a third external terminal of the integrated circuit;
A power supply device comprising: a drive winding magnetically coupled to the inductor and connected to a fourth external terminal of the integrated circuit. A power supply device according to claim 3,
A light emitting element supplied with electric power from the power supply device;
An illumination device comprising:

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