JP2007159227A - Switching power supply - Google Patents

Switching power supply Download PDF

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JP2007159227A
JP2007159227A JP2005349243A JP2005349243A JP2007159227A JP 2007159227 A JP2007159227 A JP 2007159227A JP 2005349243 A JP2005349243 A JP 2005349243A JP 2005349243 A JP2005349243 A JP 2005349243A JP 2007159227 A JP2007159227 A JP 2007159227A
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switching power
power supply
voltage
circuit
output
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JP4789605B2 (en
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Kenichi Suzuki
健一 鈴木
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Shindengen Electric Manufacturing Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a relatively inexpensive high efficiency switching power supply circuit with uniform output current. <P>SOLUTION: In the switching power supply circuit where a plurality of switching power supplies are connected in parallel, each switching power supply is provided with an output inductor 1, a filter circuit 4 where a resistor 2 and a capacitor 3 is connected in parallel with the inductor is provided, output voltage from each switching power supply and the voltage of the filter circuit are added and compared with a reference voltage 11, and the main switch of the switching power supply is controlled by the comparison signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、複数個のスイッチング電源を並列接続してあるスイッチング電源回路に関するものである。   The present invention relates to a switching power supply circuit in which a plurality of switching power supplies are connected in parallel.

複数個のスイッチング電源を並列接続して、並列運転する場合、個々の設定電圧の違いより出力電流が均一にならない事が知られており、図3に示すように、各々の電流値はスイッチング電源の負荷レギュレーションにより決定する。   When a plurality of switching power supplies are connected in parallel and operated in parallel, it is known that the output current is not uniform due to the difference in individual set voltages. As shown in FIG. Determined by the load regulation.

個々の設定電圧の違いより出力電流が均一にならない問題を解決するために、図4に示すように、スイッチング電源主回路1の出力側に設けた出力インダクタ11と直列に接続するインダクタ電流検出回路22により出力インダクタ1を流れる電流を検出し、基準電圧制御回路23によりインダクタ電流検出回路22により検出したインダクタ電流に比例した基準電圧を設けるとともに、分圧抵抗17,18で構成した出力電圧検出手段により出力電圧を検出し、前記基準電圧と出力電圧とを比較器20で比較して、比較信号をスイッチング電源主回路1に設けたメインスイッチを制御し、出力電圧を下げることにより、スイッチング電源の負荷レギュレーションを決定していた(例えば、特許文献1参照)。
特開平3−128668号公報
In order to solve the problem that the output current is not uniform due to the difference between the individual set voltages, an inductor current detection circuit connected in series with the output inductor 11 provided on the output side of the switching power supply main circuit 1 as shown in FIG. 22 detects the current flowing through the output inductor 1, and provides a reference voltage proportional to the inductor current detected by the inductor current detection circuit 22 by the reference voltage control circuit 23, and output voltage detection means comprising voltage dividing resistors 17 and 18. The reference voltage and the output voltage are compared by the comparator 20, the main switch provided in the switching power supply main circuit 1 is controlled by the comparator 20, and the output voltage is lowered. The load regulation has been determined (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 3-128668

しかし、基準電圧を下げて負荷レギュレーションを決定するために、出力電圧検出手段7,8、インダクタ電流検出回路22、並びに、この電流に比例して基準電圧を可変させる基準電圧制御回路23が必要となり、コスト増大及び電流検出回路による電源効率の低下を招くという問題がある。   However, in order to lower the reference voltage and determine the load regulation, the output voltage detection means 7 and 8, the inductor current detection circuit 22, and the reference voltage control circuit 23 that varies the reference voltage in proportion to this current are required. In addition, there is a problem in that the cost increases and the power supply efficiency decreases due to the current detection circuit.

本発明は、上記問題に鑑みてなされたものであり、比較的安価で出力電流を均一化させることによる高効率なスイッチング電源回路を提供する。   The present invention has been made in view of the above problems, and provides a high-efficiency switching power supply circuit by making the output current uniform at a relatively low cost.

上記課題を解決するために、本発明に係るスイッチング電源回路は、複数個のスイッチング電源を並列接続してあるスイッチング電源回路において、各スイッチング電源に出力インダクタを設け、このインダクタと並列に抵抗とコンデンサとを直列接続したフィルタ回路を備えてあり、前記各スイッチング電源の出力電圧と前記フィルタ回路の電圧とを加算して基準電圧と比較し、この比較信号によりスイッチング電源のメインスイッチを制御するように構成してあることを特徴とする。   In order to solve the above-described problems, a switching power supply circuit according to the present invention is a switching power supply circuit in which a plurality of switching power supplies are connected in parallel. Are connected in series, the output voltage of each switching power supply and the voltage of the filter circuit are added and compared with a reference voltage, and the main switch of the switching power supply is controlled by this comparison signal It is configured.

また、前記フィルタ回路を構成する抵抗とコンデンサとの間に接続部を設け、この接続部に抵抗を接続し、これにより得られた電圧と前記出力電圧の分割電圧とを比較するように構成してあることを特徴とする。   In addition, a connection portion is provided between the resistor and the capacitor constituting the filter circuit, the resistor is connected to the connection portion, and the voltage obtained thereby is compared with the divided voltage of the output voltage. It is characterized by being.

本発明によれば、従来のものと比べてインダクタを流れる電流を検出する回路が不必要となるため、スイッチング電源回路の低コスト化および高効率化を可能とし、さらに、前記電流検出回路を有するスイッチング電源回路と同様に、出力電流を均一化させることにより高信頼度のスイッチング電源回路を提供することが可能である。   According to the present invention, a circuit for detecting the current flowing through the inductor is not required as compared with the conventional one, so that the switching power supply circuit can be reduced in cost and efficiency, and further includes the current detection circuit. Similar to the switching power supply circuit, it is possible to provide a highly reliable switching power supply circuit by making the output current uniform.

以下、添付図面を用いて本発明スイッチング電源回路に係る実施例を説明する。図1は本発明に係るスイッチング電源回路に適用する回路を示した図である。なお、本実施例においては、スイッチング電源主回路1を一つのみ示してあるが、実際には同様のスイッチング電源主回路1を複数個並列に接続してある。図1に示すスイッチング電源回路は、スイッチング電源主回路1の出力側に出力インダクタ11を設けてある。スイッチング電源主回路1の出力側には負荷15と平滑コンデンサ16とが接続してある。   Embodiments according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing a circuit applied to a switching power supply circuit according to the present invention. In this embodiment, only one switching power supply main circuit 1 is shown, but actually, a plurality of similar switching power supply main circuits 1 are connected in parallel. The switching power supply circuit shown in FIG. 1 includes an output inductor 11 on the output side of the switching power supply main circuit 1. A load 15 and a smoothing capacitor 16 are connected to the output side of the switching power supply main circuit 1.

本発明では、スイッチング電源主回路1の出力電圧を検出する出力電圧検出手段を設けてあり、本実施例においては、スイッチング電源主回路1の出力側に分圧抵抗17,18を設けてあり、これにより、出力電圧を検出し分圧して、出力電圧信号を出力できるように構成してある。   In the present invention, output voltage detection means for detecting the output voltage of the switching power supply main circuit 1 is provided, and in this embodiment, voltage dividing resistors 17 and 18 are provided on the output side of the switching power supply main circuit 1, Thus, the output voltage is detected and divided to output an output voltage signal.

出力インダクタ11と並列に抵抗12とコンデンサ13とを直列接続したフィルタ回路14を備えてある。フィルタ回路14を構成する抵抗12とコンデンサ13との間に接続部を設け、この接続部に抵抗19を接続してある。このスイッチング電源は比較器20を設けてあり、検出側には前記分圧抵抗17,18の接続部と、フィルタ回路14に接続する抵抗19の一端とが接続し、基準側には基準電圧源21が接続してある。この比較器20により出力される比較信号によりスイッチング電源主回路1のメインスイッチを制御するように構成してある。   A filter circuit 14 in which a resistor 12 and a capacitor 13 are connected in series is provided in parallel with the output inductor 11. A connecting portion is provided between the resistor 12 and the capacitor 13 constituting the filter circuit 14, and a resistor 19 is connected to the connecting portion. This switching power supply is provided with a comparator 20, a connection portion of the voltage dividing resistors 17 and 18 and one end of a resistor 19 connected to the filter circuit 14 are connected to the detection side, and a reference voltage source is connected to the reference side. 21 is connected. The main switch of the switching power supply main circuit 1 is controlled by the comparison signal output from the comparator 20.

本発明に係るスイッチング電源回路は以下のように作用する。なお、図2に本発明に係るスイッチング電源回路における負荷レギュレーションを決定する電流−電圧波形図を示す。先ず、スイッチング電源主回路1のメインスイッチをオンさせて、出力インダクタ11に流れる電流と出力電圧を検出する。出力インダクタ11に流れる電流は出力インダクタ11の内部抵抗により検出することができる。また、出力インダクタ1と並列に接続したフィルタ回路14を構成するコンデンサ13には、出力インダクタ11に流れる電流と出力インダクタ11の内部抵抗値との積により求められる電圧が発生する。即ち、出力インダクタ11に流れる電流値と比例する電圧が発生する。この電圧をフィルタ回路14に接続する分圧抵抗19により分圧して得た分割電圧を比較器20の負の端子に入力する。   The switching power supply circuit according to the present invention operates as follows. FIG. 2 shows a current-voltage waveform diagram for determining the load regulation in the switching power supply circuit according to the present invention. First, the main switch of the switching power supply main circuit 1 is turned on to detect the current flowing through the output inductor 11 and the output voltage. The current flowing through the output inductor 11 can be detected by the internal resistance of the output inductor 11. In addition, a voltage determined by the product of the current flowing through the output inductor 11 and the internal resistance value of the output inductor 11 is generated in the capacitor 13 constituting the filter circuit 14 connected in parallel with the output inductor 1. That is, a voltage proportional to the current value flowing through the output inductor 11 is generated. A divided voltage obtained by dividing this voltage by a voltage dividing resistor 19 connected to the filter circuit 14 is input to the negative terminal of the comparator 20.

一方、出力電圧は分圧抵抗17,18で分圧して得た分割出力電圧を比較器20の負の端子に入力する。分割出力電圧とインダクタ電流に比例する分割電圧との合成電圧と基準電圧とを比較器20で比較して、比較信号をスイッチング電源主回路1に設けたメインスイッチを制御し、出力電圧を下げることにより、スイッチング電源の負荷レギュレーションを決定する。   On the other hand, the divided output voltage obtained by dividing the output voltage by the voltage dividing resistors 17 and 18 is input to the negative terminal of the comparator 20. The combined voltage of the divided output voltage and the divided voltage proportional to the inductor current and the reference voltage are compared by the comparator 20 to control the main switch provided with the comparison signal in the switching power supply main circuit 1 to lower the output voltage. Thus, the load regulation of the switching power supply is determined.

以上より、インダクタ電流に比例する分割電圧を比較器20の負の端子に入力するとともに、出力電圧の分割電圧を比較器20の負の端子に入力することにより、負荷レギュレーションを急激に下げることなく、適当な位置に設定することができる。図2に示すように、複数個のスイッチング電源を並列に接続した場合、個々の設定電圧の違いが発生するが、本発明は以上の作用により、従来のスイッチング電源装置に比べて、各々のスイッチング電源における出力電流の差が小さくなり、出力電流をより均一化させることが可能となり、高効率化かつ高信頼性を図ることができる。   As described above, the divided voltage proportional to the inductor current is input to the negative terminal of the comparator 20 and the divided voltage of the output voltage is input to the negative terminal of the comparator 20 without drastically reducing the load regulation. , Can be set to an appropriate position. As shown in FIG. 2, when a plurality of switching power supplies are connected in parallel, there is a difference in each set voltage. However, according to the present invention, each switching power supply can be compared with a conventional switching power supply apparatus. The difference in output current in the power supply is reduced, the output current can be made more uniform, and high efficiency and high reliability can be achieved.

本発明によれば、従来のものと比べてインダクタを流れる電流を検出する回路が不必要となるため、スイッチング電源回路の低コスト化を可能とし、さらに、前記電流検出回路を有するスイッチング電源回路と同様に、出力電流を均一化させることによる高効率かつ高信頼性なスイッチング電源回路を提供することができ、産業上利用可能である。   According to the present invention, a circuit for detecting the current flowing through the inductor is not required as compared with the conventional one, so that the cost of the switching power supply circuit can be reduced, and the switching power supply circuit having the current detection circuit, Similarly, a high-efficiency and high-reliability switching power supply circuit by making the output current uniform can be provided and can be used industrially.

本発明に係るスイッチング電源装置における要部の回路を示した回路図である。It is the circuit diagram which showed the circuit of the principal part in the switching power supply device which concerns on this invention. 図1図示回路における負荷レギュレーションを決定する電流−電圧波形図である。FIG. 2 is a current-voltage waveform diagram for determining load regulation in the circuit shown in FIG. 1. 従来のスイッチング電源装置における負荷レギュレーションを決定する電流−電圧波形図である。It is a current-voltage waveform diagram which determines the load regulation in the conventional switching power supply device. 従来のスイッチング電源装置の例を示した回路図である。It is the circuit diagram which showed the example of the conventional switching power supply device.

符号の説明Explanation of symbols

1 スイッチング電源主回路
11 出力インダクタ
12 抵抗
13 コンデンサ
14 フィルタ回路
15 負荷
16 平滑コンデンサ
17,18,19 分圧抵抗
20 比較器
21 基準電圧源
22 電流検出回路
23 基準電圧制御回路
1 switching power supply main circuit 11 output inductor 12 resistor 13 capacitor 14 filter circuit 15 load 16 smoothing capacitor 17, 18, 19 voltage dividing resistor
20 Comparator 21 Reference Voltage Source 22 Current Detection Circuit 23 Reference Voltage Control Circuit

Claims (2)

複数個のスイッチング電源を並列接続してあるスイッチング電源回路において、各スイッチング電源に出力インダクタを設け、このインダクタと並列に抵抗とコンデンサとを直列接続したフィルタ回路を備えてあり、前記各スイッチング電源の出力電圧と前記フィルタ回路の電圧とを加算して基準電圧と比較し、この比較信号によりスイッチング電源のメインスイッチを制御するように構成してあることを特徴とするスイッチング電源回路。 In a switching power supply circuit in which a plurality of switching power supplies are connected in parallel, an output inductor is provided for each switching power supply, and a filter circuit in which a resistor and a capacitor are connected in series with the inductor is provided. A switching power supply circuit configured to add an output voltage and a voltage of the filter circuit to compare with a reference voltage, and to control a main switch of the switching power supply by the comparison signal. 前記フィルタ回路を構成する抵抗とコンデンサとの間に接続部を設け、この接続部に抵抗を接続し、これにより得られた電圧と前記出力電圧の分割電圧とを比較するように構成してあることを特徴とする請求項1記載のスイッチング電源回路。 A connecting part is provided between the resistor and the capacitor constituting the filter circuit, and a resistor is connected to the connecting part, and the voltage obtained thereby is compared with the divided voltage of the output voltage. The switching power supply circuit according to claim 1.
JP2005349243A 2005-12-02 2005-12-02 Switching power supply circuit Expired - Fee Related JP4789605B2 (en)

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JP4789605B2 JP4789605B2 (en) 2011-10-12

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1169789A (en) * 1997-08-11 1999-03-09 Tokimec Inc Switching power supply device
JP2005500795A (en) * 2001-08-21 2005-01-06 インターシル アメリカズ インク Thermally compensated current sensing of intrinsic power converter elements
JP2005110369A (en) * 2003-09-29 2005-04-21 Murata Mfg Co Ltd Ripple converter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1169789A (en) * 1997-08-11 1999-03-09 Tokimec Inc Switching power supply device
JP2005500795A (en) * 2001-08-21 2005-01-06 インターシル アメリカズ インク Thermally compensated current sensing of intrinsic power converter elements
JP2005110369A (en) * 2003-09-29 2005-04-21 Murata Mfg Co Ltd Ripple converter

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