JP5192684B2 - Power circuit - Google Patents

Description

The present invention relates to a power supply circuit , for example, a power supply circuit suitable for a case where power is distributed and supplied to several electrical components scattered on one board.

  Due to the demand for a reduction in heat generation by reducing the leakage current of a CPU (Central Processing Unit) and the progress of microfabrication technology in integrated circuits, the power supply has been promoted to have a low voltage and a large capacity. There is also a demand that the output of the power circuit is several tens of amps (ampere) at 1 V (Volt) or less. Thus, when the output voltage of the power supply circuit is drastically reduced, the influence of voltage drop due to wiring, which was not a problem, becomes serious in the conventional power supply configuration of about 5 A at 5V.

  Therefore, from a conventional method in which power is collectively supplied from one power supply circuit to each integrated circuit on a board (printed circuit board), distributed power supply (POL: POL) in which power is individually arranged in the immediate vicinity of each integrated circuit. Point Of Load) is the mainstream. The power source used for the distributed power supply method is generally required to be versatile. For this reason, power supply circuits such as modules and integrated circuits that achieve a wide input voltage range, arbitrarily settable low output voltage and high output current, are marketed in various forms by many power supply manufacturers and semiconductor manufacturers. It has become.

  These commercially available power supply circuits each have input / output conditions for obtaining the highest conversion efficiency. However, many devices and boards are not necessarily used in the best input / output conditions. For this reason, this has been a factor in hindering the reduction in power consumption of the entire apparatus system.

FIG. 7 shows an example of a conventional distributed power supply type power supply circuit. In the power supply circuit 400 adopting a distributed power system (for example, see Patent Document 1), in the vicinity of the first to third circuit that requires an individual to a power such as load circuit 401 ₁ to 401 ₃ that is disposed on the not-shown board The first and second non-insulated converters 402 ₁ , 402 ₂ or the series regulator 403 are arranged to supply power suitable for each. The isolated converter 405 connected to the input voltage source 404 supplies the intermediate bus voltage 406 to the first and second non-isolated converters 402 ₁ and 402 ₂ and the series regulator 403.

The isolated converter 405 uses a single output power source that outputs a relatively high voltage such as + 12V. Non-insulated converters such as the first and second non-isolated converters 402 ₁ and 402 ₂ that receive the intermediate bus voltage 406 operate with a wide range of input voltages. Module types that can be set arbitrarily are widely used. As the series regulator 403, a circuit component such as an external resistor that can arbitrarily set an output voltage is also widespread. This facilitates sharing of hardware of a power supply unit (not shown).

  FIG. 8 shows the conversion efficiency characteristics of a general non-insulated converter. In this figure, the horizontal axis represents the input voltage of the non-insulated converter, and the vertical axis represents the conversion efficiency. A solid line 421 is a curve representing the conversion efficiency characteristic when the output voltage required by the load circuit 101 (FIG. 7) is a volt (V). In this case, the conversion efficiency peaks at the input voltage Va, and the conversion efficiency decreases as the input voltage goes away from the voltage Va. When the output voltage is b volts different from a volts, the conversion efficiency characteristic indicated by the broken line 422 is obtained. In this case, the conversion efficiency peaks at an input voltage Vb different from the input voltage Va, and the conversion efficiency decreases as the input voltage moves away from the voltage Vb.

Thus, the non-insulated converter has different input voltages at which the conversion efficiency peaks depending on the output voltage required by the load circuit 101. Therefore, an input voltage corresponding to the voltage required by the load circuit 101 is desirable for improving the conversion efficiency. The series regulator 403 shown in FIG. 7 is a step-down constant voltage power source in which a voltage control element is connected in series with a load. The larger the input / output potential difference, the greater the internal loss. Therefore, in the distributed power supply type power supply circuit 400 shown in FIG. 7 using the general-purpose first and second non-insulated converters 402 ₁ and 402 ₂ and the series regulator 403, the conversion efficiency of the power supply is set to the best condition. It is difficult to use, and the reduction in efficiency of the entire system has been a problem.

On the other hand, a first converter (not shown) and a second converter (not shown) that further converts the output of the first converter are arranged in series, and a load circuit (not shown) is arranged on the output side. At the same time, a proposal has been made to provide a control circuit (not shown) for controlling both converters (for example, see Patent Document 2). In this latter proposal (hereinafter, the previous proposal is referred to as the first proposal and the later proposal is referred to as the second proposal), the first converter converts the AC power supply (not shown) into a DC power supply (not shown). Functions as a circuit for power factor improvement. The second converter uses the converted DC power supply to adjust the switching operation frequency on the primary side of the transformer (not shown) to convert it to a voltage required by the load circuit.
Japanese Patent Laying-Open No. 2004-260887 (paragraph 0024, FIG. 2) JP-A-10-341572 (paragraphs 0003 and 0023, FIG. 1)

  In the second proposal, although the power factor of the first converter is improved, the DC voltage output from the first converter becomes a voltage value that does not assume the conversion efficiency of the second converter. That is, in both the first proposal and the second proposal, the conversion efficiency of the non-insulated converter shown in FIG. 8 or the circuit portion that performs the switching operation on the primary side of the transformer described above may deteriorate, reducing the power consumption. This may result in an inefficient power supply circuit that does not contribute to.

Accordingly, an object of the present invention is to provide a power supply circuit that improves the conversion efficiency of a power supply when two types of converters are connected in series to supply power to a load circuit.

In the present invention, (a) when a centralized management circuit arranged outside outputs a voltage required by a predetermined load circuit existing in each circuit to be managed as an output voltage setting signal. An output voltage setting signal receiving means for receiving an output voltage setting signal for its own circuit; and the predetermined load circuit described above as an output voltage by converting the input voltage into a voltage received by the output voltage setting signal receiving means And (b) an isolated converter that receives power from an input power supply, converts the input voltage to an arbitrary voltage, and inputs the voltage to the non-isolated converter. , (c) in this state of being electrically disconnected from the output side of the insulating converter inputs an output voltage the output from the non-insulated converter described above, based on the previously measured result Come, the best input voltage conversion efficiency and the intermediate bus voltage calculating means for calculating an intermediate bus voltage, the above-mentioned intermediate bus voltage calculated in the intermediate bus voltage calculating means of the non-insulated converter described above that pair on the output voltage An intermediate bus voltage determining means comprising an intermediate bus voltage indicating means for indicating the intermediate bus voltage obtained by calculation so as to match the arbitrary voltage output from the isolation converter. It has.

In the present invention, (a) a centralized management circuit arranged outside outputs a voltage required by a predetermined load circuit existing in each circuit to be managed as an output voltage setting signal. When receiving the output voltage setting signal receiving means for receiving the output voltage setting signal for its own circuit, the input voltage is converted into a voltage received by the output voltage setting signal receiving means and the predetermined voltage is set as the output voltage. A non-insulating converter having a voltage converting means for outputting to a load circuit; and (b) an insulating converter for receiving power supplied from an input power source and converting the input voltage into a plurality of different output voltages and outputting the same. (C) A plurality of different output voltages are input from the isolated converter, and one of them is selected and input to the non-isolated converter as the input voltage. A selecting means for, (d) while the output side of the above-mentioned insulating converter electrically disconnected inputs an output voltage the output from the non-insulated converter described above, based on the previously measured result An intermediate bus voltage calculation means for calculating the input voltage with the highest conversion efficiency of the non-insulated converter for the output voltage as an intermediate bus voltage, and an output close to the intermediate bus voltage calculated by the intermediate bus voltage calculation means The power supply circuit includes intermediate bus voltage determination means including intermediate bus voltage instruction means for instructing voltage selection.

As described above, according to the present invention, since the output voltage of the non-insulated converter is converted to the voltage required by the load circuit, this requirement can be satisfied even if the voltage required by the load circuit is different. Furthermore, since the isolated converter gives priority to the conversion efficiency of the non-isolated converter and outputs the intermediate bus voltage as its output voltage, not only the same power supply circuit can respond to the design change of the load circuit, but also the power supply circuit Can be made into common parts. For this reason, it is possible to reduce the cost by mass production of the power supply circuit and to shorten the design time of various circuits including the power supply circuit.

  Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 shows a configuration of a power supply circuit according to an embodiment of the present invention. The power supply circuit 100 is, for example, a first to third circuits for distributed power power to the load circuit 101 ₁ to 101 ₃ as a load circuit which is arranged at a distance from one another on the not-shown board.

  The power supply circuit 100 according to this embodiment includes an input voltage source 102 that outputs a predetermined voltage, and an insulating converter 104 that inputs the output voltage 103. The input voltage source 102 outputs a relatively high voltage such as + 12V, for example. The isolated converter 104 is a DC (Direct Current) -DC converter in which the input and the output are insulated. The set voltage signal 106 is input from the output voltage setting circuit 105 and converted into an intermediate bus voltage 107 as an output voltage. It has become.

The intermediate bus voltage 107 is supplied to _first to third non-insulated converters 108 _{1 to} 108 ₃ , which share a part of input and output. These first to third non-insulated converters 108 _{1 to} 108 ₃ are connected to corresponding ones of the _first to third load circuits 101 _{1 to} 101 ₃ . The first to third non-insulated converters 108 _{1 to} 108 ₃ are arranged in close proximity to the corresponding ones of the _first to third load circuits 101 _{1 to} 101 ₃ , respectively, and when supplying power to them, A distributed power supply configuration that minimizes the effects of voltage drop is adopted.

The first to third load circuits 101 _{1 to} 101 ₃ output voltages required by the respective circuits as output voltage setting signals 109 _{1 to} 109 ₃ . These output voltage setting signals 109 _{1 to} 109 ₃ are input to corresponding ones of the _first to third output voltage setting circuits 111 _{1 to} 111 ₃ . The first to third output voltage setting circuits 111 _{1 to} 111 ₃ input the respective output voltage determination signals 112 _{1 to} 112 ₃ to the corresponding ones of the _first to third non-insulated converters 108 _{1 to} 108 _3. Thus, each of the first to third load circuits 101 _{1 to} 101 ₃ is automatically set to a required voltage.

Further, the power supply circuit 100 of this embodiment is provided with an intermediate bus voltage determination circuit 113 which is connected to both the first non-insulated converter 108 _first output side and the output voltage setting circuit 105. Intermediate bus voltage determination circuit 113 receives the output voltage 114 ₁ which is the first automatic setting of the non-insulated converter 108 _1, non-insulated converter 108 ₁ first such that the optimum conversion efficiency for this The intermediate bus voltage 107 as the input voltage condition is determined. Then, a bus voltage change signal 115 for realizing this is supplied to the output voltage setting circuit 105. As a result, the output voltages 114 _{1 to} 114 ₃ output from the _first to third non-insulated converters 108 _{1 to} 108 ₃ are automatically set.

FIG. 2 shows a series of operations for power supply control of the power supply circuit. This will be described with reference to FIG. In order to simplify the description, this description is limited to the _first load circuit 101 ₁ .

  First, in order to operate the power supply circuit 100, the output voltage 103 of the input voltage source 102 is applied to the insulation converter 104 (step S201). Thereby, the insulation converter 104 starts an operation (step S202), and an initial output voltage as a default value is generated as an intermediate bus voltage 107 on the output side (step S203).

The first non-insulated converter 108 ₁ is activated when the intermediate bus voltage 107 is applied (step S204). At this time, the first non-insulated converter 108 ₁ uses, as the output voltage determination signal 112 ₁ , a signal for setting the output voltage value required by the first load circuit 101 ₁ from the _first output voltage setting circuit 111 _1. Obtain (step S205). Thereby, the first non-insulated converter 108 ₁ determines its output voltage and generates the determined output voltage 114 ₁ (step S206). This output voltage 114 ₁ is supplied to the _first load circuit 101 ₁ (step S207).

The intermediate bus voltage determination circuit 113 detects the voltage supplied to the _first load circuit 101 ₁ by inputting the output voltage 114 ₁ of the first non-insulated converter 108 ₁ (step S208). The first non-insulated converter 108 ₁ determines an optimum intermediate bus voltage 107 as an input voltage condition for achieving optimum conversion efficiency (step S209), and a bus voltage change signal for realizing this. 115 is output to the output voltage setting circuit 105 (step S210). The output voltage setting circuit 105 changes the intermediate bus voltage 107 output from the isolation converter 104 from the initial output voltage using the bus voltage change signal 115 (step S211). Thereby the insulating converter 104, it is possible to output a first non-insulated converter 108 ₁ best is the best input voltage conditions for obtaining a high conversion efficiency of intermediate bus voltage 107.

  FIG. 3 shows a circuit configuration embodying the main part of FIG. The circuit portion shown in FIG. 3 corresponds to a region surrounded by a broken line 117 in the power supply circuit 100 shown in FIG.

The isolated converter 104 for inputting the output voltage 103 of the input voltage source 102 shown in FIG. 1 and the first non-insulated converter 108 ₁ connected to the output side thereof are respectively modularized, and have an input terminal IN and an output terminal. V _OUT and a voltage adjustment terminal TRIM are provided. Here, the voltage adjustment terminal TRIM is a terminal that can arbitrarily set the intermediate bus voltage 107 or the output voltage 114 ₁ output from the output terminal V _OUT .

Such a voltage adjustment terminal TRIM makes the output voltage of the output terminal _VOUT variable by changing the voltage applied to a predetermined location inside the corresponding module or changing the value of the digital signal supplied to this predetermined location. ing. In general, the voltage output from the output terminal V _OUT is often made variable by changing the impedance of an electrical component such as a resistor. Also in the power supply circuit 100 of the present embodiment, the output voltage can be adjusted by such a voltage adjustment terminal TRIM. The configuration and use method of the voltage adjustment terminal TRIM itself is not particularly limited.

The first load circuit 101 ₁ arranged on the output side of the first non-insulated converter 108 ₁ is composed of circuit components that receive power supply such as an IC (Integrated Circuit) 121, and the output voltage is contained therein. A setting signal output unit 122 is provided. The output voltage setting signal output unit 122 may be configured as an internal circuit of the IC 121. The output voltage setting signal output unit 122 generates an output voltage setting signal 109 ₁ to obtain a voltage required by the first load circuit 101 ₁ and outputs the output voltage setting signal 109 ₁ to the first output voltage setting circuit 111 _1. It has become.

Of course, it is not always necessary that the output voltage setting signal output unit 122 itself generates the output voltage setting signal 109 ₁ . For example, centralized control circuit 125 disposed on the outside as indicated by a broken line in FIG. 3, concentrate the respective voltages required by the first to third load circuit 101 ₁ to 101 ₃ shown in FIG. 1 In the case of management, the output voltage setting signal 126 ₁ obtained from this is received by the output voltage setting signal output unit 122, and the output voltage setting signal 109 ₁ is output based on this. Good.

The first output voltage setting circuit 111 ₁ for receiving the output voltage setting signal 109 _1, for example, a variable resistor 127 _1, so as to supply the resistance value corresponding to the input signal to the voltage adjustment terminal TRIM ing.

The intermediate bus voltage determination circuit 113 has a voltage detection circuit 131 that receives the output voltage 114 ₁ of the first non-insulated converter 108 ₁ , a storage circuit 132 that stores predetermined conversion efficiency characteristic data, and a maximum conversion efficiency. A voltage value selection circuit 133 that selects an input voltage value, and a bus voltage change signal output circuit 134 that supplies the voltage value selected by the voltage value selection circuit 133 to the output voltage setting circuit 105 as a bus voltage change signal 115. Yes. Here, as described with reference to FIG. 8, the input voltage V having the highest conversion efficiency (the conversion efficiency reaches a peak) for each value of the output voltage 114 ₁ is stored in the memory circuit 132. Stored as table information as address information.

FIG. 8 shows two examples where the output voltage is a volt and b volt, but the table information stored in the storage circuit 132 corresponds to the “output voltage” of the entire range assumed as the output voltage 114 _1. Thus, it is a list of “input voltage V” with the highest conversion efficiency. This consists of a relationship between “output voltage” and “input voltage V” obtained by actual measurement. Of course, instead of such table information, an arithmetic expression that approximately obtains the “input voltage V” that provides the best conversion efficiency when the “output voltage” is given may be stored in the storage circuit 132. .

The voltage value selection circuit 133 converts the output voltage 114 ₁ detected by the voltage detection circuit 131 into corresponding address information, and the “input” corresponding to the corresponding “output voltage” from the table information stored in the storage circuit 132. Read voltage V ". A bus voltage change signal 115 for causing the output voltage setting circuit 105 to set the “input voltage V” is output from the bus voltage change signal output circuit 134.

Accordingly, if the voltage detection circuit 131 outputs the address information corresponding to the output voltage 114 ₁ and the storage circuit 132 directly outputs the bus voltage change signal 115 corresponding thereto, the intermediate bus voltage determination circuit 113. The configuration can be further simplified. The same applies to the case where an arithmetic expression is stored in the memory circuit 132 for calculation.

The output voltage setting circuit 105 includes a variable resistor 136, for example, and supplies a resistance value corresponding to the input bus voltage change signal 115 to the voltage adjustment terminal TRIM of the insulation converter 104. As a result, the first to third non-insulated converters 108 _{1 to} 108 ₃ can change the intermediate bus voltage 107 as the input voltage from the initial output voltage as the default value to the optimum intermediate bus voltage. Become.

As described above, according to the power supply circuit 100 of the present embodiment, the output voltage 114 ₁ of the first non-insulated converter 108 ₁ is set according to the load of the _first load circuit 101 ₁ , and further the first non-insulating decide to change the intermediate bus voltage 107 so as to optimize the conversion efficiency with respect to the output voltage 114 ₁ of the insulating converter 108 _1. This enables a highly efficient power supply configuration.

Further, in the present embodiment, the first output voltage setting circuit is also applied when, for example, a circuit component such as the IC 121 constituting the _first load circuit 1011 is changed and the required voltage is changed at the time of design, for example. 111 ₁ is applied to the first voltage after the change the output voltage ₁₁₄₁ of the non-insulated converter 108 _1. Therefore, the circuit configuration as the power supply circuit 100 can be used as it is, and design man-hours and delivery time can be shortened. Thus, since the hardware of the power supply circuit 100 can be shared with the various load circuits 101, the cost reduction by mass production becomes easy.

  <First Modification of Invention>

  FIG. 4 shows the configuration of the power supply circuit in the first modification of the present invention. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In addition, the letter “A” is appended to the end of the number representing the circuit component corresponding to the circuit component shown in FIG.

In the previous embodiment, as shown in FIG. 1, one insulating converter 104 is shared by the _first to third non-insulating converters 108 _{1 to} 108 ₃ . In the power supply circuit 100A of the first modified example, first to third insulating converters 104 _{1 to} 104 ₃ are provided corresponding to the _first to third load circuits 101 _{1 to} 101 ₃ , respectively. Therefore, in these first to third insulating converter 104 _{1-104 3} one by one to form to correspond, is provided with a first to third intermediate bus voltage determination circuit 113 ₁ to 113 _3.

The output voltage 114 ₁ output from the first non-insulated converter 108 ₁ is supplied to the first intermediate bus voltage determination circuit 113 ₁ in addition to being supplied to the _first load circuit 101 ₁ . The first intermediate bus voltage determination circuit 113 _1, will supply the set voltage signal 106 ₁ for setting the first intermediate bus voltage 107 ₁ in the first insulating converter 104 _1. Depending on the device configuration, the first output voltage setting circuit 105 ₁ is arranged between the first intermediate bus voltage 107 ₁ and the first isolation converter 104 ₁ like the power supply circuit 100 of the embodiment shown in FIG. May be.

The output voltage 114 ₂ output from the second non-insulated converter 108 ₂ is supplied to the second intermediate bus voltage determination circuit 113 ₂ in addition to being supplied to the _second load circuit 101 ₂ . Second intermediate bus voltage determination circuit 113 ₂ supplies a set voltage signal 106 ₂ for setting the second intermediate bus voltage 107 ₂ in the second insulating converter 104 _2. Depending on the device configuration, a second output voltage setting circuit 105 ₂ such as the power supply circuit 100 of the embodiment may be disposed between the second intermediate bus voltage 107 ₂ and the second isolation converter 104 ₂ .

Similarly, the output voltage 114 ₃ output from the third non-insulated converter 108 ₃ is supplied to the third intermediate bus voltage determination circuit 113 ₃ in addition to being supplied to the _third load circuit 101 ₃ . A third intermediate bus voltage determination circuit 113 ₃ supplies a set voltage signal 106 ₃ for setting the third intermediate bus voltage 107 ₃ in the third insulating converter 104 _3. Depending on the device configuration, the third output voltage setting circuit 105 ₃ may be arranged between the third intermediate bus voltage 107 ₃ and the third isolation converter 104 ₃ similarly as in the power supply circuit 100 of the embodiment. .

According to the power supply circuit 100A of the first modification, when the voltages required by the _first to third load circuits 101 _{1 to} 101 ₃ are different, the first to third intermediate bus voltages 107 _{1 are used.} it can be set to 107 ₃ to match the voltage value, respectively. Therefore, it is possible to realize the optimum input / output condition when performing distributed power feeding to each of the _first to third load circuits 101 _{1 to} 101 ₃ .

  <Second Modification of Invention>

  FIG. 5 shows an outline of the configuration of the power supply circuit according to the second modification of the present invention. In FIG. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In addition, the letter “B” is added to the end of the number representing the circuit component corresponding to the circuit component shown in FIG.

In the power supply circuit 100B shown in the second modification, a DC input voltage source 102B is connected to a pair of input terminals 301 and 302 of the insulating converter 104B. First to third output terminals 303 to 305 are provided on the output side of the insulating converter 104B, and the first to third output voltages 306 to 308 are output. First to third output voltages 306 to 308 are adapted to respectively supplied to the first to third switcher circuit 309 _{1 to 309 3.}

The first to third switcher circuits 309 _{1 to} 309 ₃ include first to third switching elements 311 to 313 that individually input the first to third output voltages 306 to 308, respectively. The output sides of the first to third switching elements 311 to 313 are connected in common, and the first to third intermediate bus voltages 107 ₁ are connected to the corresponding ones of the first to _third non-insulated converters 108 _{1 to} 108 _3. It is adapted to output as to 107 _3.

The first intermediate bus voltage 107 ₁ is input to the _first non-isolated converter 108 ₁ . The output voltage 114 ₁ of the first non-insulated converter 108 ₁ is input to the first intermediate bus voltage determination circuit 113 ₁ . The first intermediate bus voltage determination circuit 113 ₁ is substantially the same circuit as the intermediate bus voltage determination circuit 113 of the previous embodiment. The bus voltage change signal 115 ₁ output from the first intermediate bus voltage determination circuit 113 ₁ is supplied to the _first switcher circuit 309 _1, and _one of the first to third switching elements 311 to 313 is It is supposed to be turned on.

The second intermediate bus voltage 107 ₂ is input to the _second non-isolated converter 108 ₂ . The output voltage 114 ₂ of the second non-insulated converter 108 ₂ is input to the second intermediate bus voltage determination circuit 113 ₂ . The second intermediate bus voltage determination circuit 113 ₂ is substantially the same circuit as the intermediate bus voltage determination circuit 113 of the previous embodiment. The bus voltage change signal 115 ₂ output from the second intermediate bus voltage determination circuit 113 ₂ is supplied to the _second switcher circuit 309 ₂ , and one of the first to third switching elements 311 to 313 is It is supposed to be turned on.

The third intermediate bus voltage 107 ₃ is input to the _third non-isolated converter 108 ₃ . The output voltage 114 of the _third non-insulated converter 108 ₃ is input to the third intermediate bus voltage determination circuit 113 _3. A third intermediate bus voltage determination circuit 113 ₃ is an intermediate bus voltage determination circuit 113 substantially the same circuit of the previous embodiment. Bus voltage change signal 115 ₃ output from the third intermediate bus voltage determination circuit 113 ₃ is supplied to the third switcher circuit 309 _3, one of the first to third switching elements 311 - 313 It is supposed to be turned on.

  FIG. 6 specifically shows the configuration of the insulating converter of the second modification. The insulating converter 104B includes an input smoothing capacitor 321 connected to a pair of input terminals 301 and 302, a transformer 323 having one end of a primary winding connected to the input terminal 301 side, and the other end of the primary winding of the transformer 323. And a field effect transistor 324 having a drain and a source connected between the input terminal 302 and a first having an anode connected to each point in the direction in which the amount of winding decreases when viewed from the ground side of the secondary winding of the transformer 323. To third diodes 326 to 328, and first to third output smoothing capacitors 331 to 333 having one ends connected to the cathodes of the first to third diodes 326 to 328 and the other ends grounded. The constant voltage control circuit 335 has one end connected to a connection point between the first diode 326 and the first output smoothing capacitor 331.

  Here, the connection point between the first diode 326 and the first output smoothing capacitor 331 is connected to the first output terminal 303, and the connection point between the second diode 327 and the second output smoothing capacitor 332 is A second output terminal 304 is connected. A connection point between the third diode 328 and the third output smoothing capacitor 333 is connected to the third output terminal 305. Further, a pulse signal 337 output from the constant voltage control circuit 335 and turned on / off at a predetermined frequency and voltage change is applied to the gate of the field effect transistor 324.

In the power supply circuit 100B having such a second modification, in order to achieve optimum output conditions for performing distributed power to the respective first to third load circuit 101 ₁ to 101 ₃ shown in FIG. 5 The first to third switcher circuits 309 _{1 to} 309 ₃ are used to select the intermediate bus voltage from the first to third output voltages 306 to 308 having different voltages in advance, so that the first to third intermediate voltages are selected. The device is designed to output the bus voltages 107 _{1 to} 107 ₃ .

As described above, in the power supply circuit 100B of the second modified example, the first to third output voltages 306 to 308 are changed according to the voltages required by the _first to third load circuits 101 _{1 to} 101 ₃ , respectively. A desired voltage can be selected as the _first to third intermediate bus voltages 107 _{1 to} 107 ₃ . Therefore, as compared with the power supply circuit 100A of the first modified example, it is not necessary to provide insulation type converters as many as the load circuits 101 _{1 to} 101 ₃ . For this reason, the manufacturing cost can be reduced by simplifying the circuit, and the space of the power supply circuit on the printed circuit board can be saved.

In the power supply circuit 100B of the second modified example, the ratio of the number of turns of the secondary winding (output winding) of the transformer 323 is the same as that of the first to third load circuits 101 _{1 to} 101 ₃ . Does not need to be set strictly for the voltage required. Even if a simple method of selecting a desired voltage from the first to third output voltages 306 to 308 by the first to _third switcher circuits 309 _{1 to} 309 ₃ is adopted, the intermediate bus voltage 107 _{1-107 3} because the first to third non-isolated converter 108 _{1-108 3} individually adjust the output voltage 114 _{1-114 3} in the subsequent stage is performed, high-precision voltage setting is not required That's why. Of course, the first to third non-insulated converters 108 _{1 to} 108 ₃ have an advantage that the intermediate bus voltage 107 can be selected from three different voltages closer to a desired voltage unlike the embodiment.

  Further, in the power supply circuit 100B of the second modified example, one of the first to third output voltages 306 to 308 (only the first output voltage 306 in this modified example) is supplied to the constant voltage control circuit. 335 is configured to feed back. Therefore, for the remaining two output voltages (the second and third output voltages 307 and 308 in this modification), the output voltage is determined by the turn ratio of the transformer 323. However, proportional voltages are output to the first to third output terminals 303 to 305 according to the turns ratio of the transformer 323, respectively. For this reason, by controlling the output voltage of the entire isolation converter 104B based on the output voltage output from one output terminal, the output stability is stable compared to the case of individually controlling the output voltage of each output terminal. Although the degree is inferior, the stability sufficient for practical use can be obtained as the intermediate bus voltage.

However, in this second modification, the intermediate converter voltage from the first to third output voltages 306 to 308 whose voltages are stepwise different from those of the previous embodiment and the first modification is different in the insulating converter 104B. Will be selected. For this reason, the voltages selected as the _first to third intermediate bus voltages 107 _{1 to} 107 ₃ are different from the voltages optimally determined in advance by the circuit design, and become values approximate to the optimal location. However, even in the selection of the _first to third intermediate bus voltages 107 _{1 to} 107 ₃ , the first to third loads are selected by the selection from the first to third output voltages 306 to 308. If the voltage required by each of the circuits 101 _{1 to} 101 ₃ is approximated within a certain error range of the voltage, a sufficiently high conversion efficiency can be expected practically. Further, since the first to third switcher circuits 309 _{1 to} 309 ₃ are used, not only the circuit is simplified, but also the first to third intermediate bus voltages 107 _{1 to} 107 for the change of the load. ₃ can be made to correspond automatically.

Of course, the first to third switcher circuits 309 _{1 to} 309 ₃ are not limited to switches having mechanical contacts, and may be configured by electronic switches using semiconductors. Of course, the number of load circuits 101 and the number of stepped output voltages in the insulating converter 104B are not limited to the embodiment or the modification. The input voltage source may be an AC voltage source. In this case, a rectifier circuit may be provided on the primary side of the transformer 323 shown in FIG. 6, or the input smoothing capacitor 321 and the field effect transistor 324 may be provided. Omitted and alternating current may be applied to the primary coil.

It is a block diagram showing the structure of the power supply circuit in one Example of this invention. It is explanatory drawing showing a series of operation | movement of the power supply control in the power supply circuit of a present Example. FIG. 2 is a block diagram illustrating a circuit configuration in which the main part of FIG. 1 is embodied in the present embodiment. It is a block diagram showing the structure of the power supply circuit in the 1st modification of this invention. It is a block diagram showing the outline | summary of the structure of the power supply circuit in the 2nd modification of this invention. It is a circuit diagram showing concretely the composition of the insulation converter of the 2nd modification. It is the block diagram which showed an example of the power supply circuit of the conventional distributed power supply system. It is a characteristic view showing the conversion efficiency characteristic of a general non-insulated converter.

Explanation of symbols

100, 100A, 100B Power supply circuit 101 ₁ 1st load circuit 101 ₂ 2nd load circuit 101 ₃ 3rd load circuit 102 Input voltage source 104, 104B Isolation converter 105 Output voltage setting circuit 107 Intermediate bus voltage 107 ₁ 1st Intermediate bus voltage 107 ₂ second intermediate bus voltage 107 ₃ third intermediate bus voltage 108 non-isolated converter 108 ₁ first non-isolated converter 108 ₂ second non-isolated converter 108 ₃ third non-isolated converter 111 ₁ First output voltage setting circuit 111 ₂ Second output voltage setting circuit 111 ₃ Third output voltage setting circuit 113 Intermediate bus voltage determination circuit 113 ₁ First intermediate bus voltage determination circuit 113 ₂ Second intermediate bus voltage determination Circuit 113 ₃ Third intermediate bus voltage determination circuit 303 First output terminal 304 Second output terminal 305 Third output terminal 309 ₁ First switcher circuit 309 ₂ Second switcher circuit 309 ₃ Third switcher circuit 335 Constant voltage control circuit

Claims (6)

When an externally arranged centralized management circuit outputs a voltage required for a predetermined load circuit existing in each circuit to be managed as an output voltage setting signal, the output for its own circuit An output voltage setting signal receiving means for receiving a voltage setting signal; and a voltage converting means for converting the input voltage into a voltage received by the output voltage setting signal receiving means and outputting the output voltage to the predetermined load circuit. A non-isolated converter with
An isolated converter that receives power from an input power supply, converts the input voltage into an arbitrary voltage, and inputs the voltage to the non-isolated converter;
The output voltage output from the non-isolated converter is input in a state of being electrically disconnected from the output side of the isolation converter, and the most of the non-isolated converter with respect to the output voltage is based on a result of actual measurement. An intermediate bus voltage calculation means for calculating an input voltage with good conversion efficiency as an intermediate bus voltage, and the arbitrary voltage output from the isolation converter is matched with the intermediate bus voltage calculated by the intermediate bus voltage calculation means. Intermediate bus voltage determining means comprising intermediate bus voltage indicating means for indicating the intermediate bus voltage obtained by calculation;
A power supply circuit comprising:   2. The power supply circuit according to claim 1, wherein there are a plurality of non-insulated converters, one of which is connected to the intermediate bus voltage determining means. The non-isolated converter, the isolated converter, and the intermediate bus voltage determining means exist in a plurality corresponding to each one, and each non-isolated converter is connected to the corresponding intermediate bus voltage determining means. The power supply circuit according to claim 1. When an externally arranged centralized management circuit outputs a voltage required for a predetermined load circuit existing in each circuit to be managed as an output voltage setting signal, the output for its own circuit An output voltage setting signal receiving means for receiving a voltage setting signal; and a voltage converting means for converting the input voltage into a voltage received by the output voltage setting signal receiving means and outputting the output voltage to the predetermined load circuit. A non-isolated converter with
An insulation converter that receives power from an input power supply, converts the input voltage into a plurality of different output voltages, and outputs the output voltage;
Selection means for inputting the plurality of different output voltages from the isolation converter and selecting one of them to be input to the non-isolation converter as the input voltage;
The output voltage output from the non-isolated converter is input in a state of being electrically disconnected from the output side of the isolation converter , and based on the result of measurement in advance, Intermediate bus voltage calculating means for calculating an input voltage with good conversion efficiency as an intermediate bus voltage, and intermediate bus voltage indicating means for instructing selection of an output voltage close to the intermediate bus voltage calculated by the intermediate bus voltage calculating means. An intermediate bus voltage determination means provided with the power supply circuit.   The non-isolated converter and the intermediate bus voltage determining means are present in a plurality corresponding to each other, and each non-isolated converter is connected to the corresponding intermediate bus voltage determining means. 4. The power supply circuit according to 4. The intermediate bus voltage determination means uses table information in which input voltages of the non-isolated converter with good conversion efficiency for various output voltages of the non-isolated converter are associated with each other,
5. The power supply circuit according to claim 1, wherein the power supply circuit is means for instructing the intermediate bus voltage.

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