JP2002252979A - Switching power source - Google Patents

Switching power source

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Publication number
JP2002252979A
JP2002252979A JP2001050531A JP2001050531A JP2002252979A JP 2002252979 A JP2002252979 A JP 2002252979A JP 2001050531 A JP2001050531 A JP 2001050531A JP 2001050531 A JP2001050531 A JP 2001050531A JP 2002252979 A JP2002252979 A JP 2002252979A
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Prior art keywords
switching power
voltage
input voltage
output
width
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Pending
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JP2001050531A
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Japanese (ja)
Inventor
Yutaka Sekine
豊 関根
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Shindengen Electric Mfg Co Ltd
新電元工業株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive switching power source, which has a good characteristic against sudden change in an input voltage and is highly stable when a load is light and the on-width is more than 50%, in a switching power source for communication equipment for which a stable output voltage is required even if the input voltage suddenly changes, because a live wire need be inserted and pulled out. SOLUTION: The switching power source for controlling the output voltage by the on-width signal for a switching element comprises a PWM(pulse width modulation) comparator for determining the on-width, an oscillator for a constant frequency, wherein the inclination of a triangular wave is made variable by an input voltage, and an error amplifier for amplifying the difference between the output voltage and a reference voltage. The PWM comparator compares an output waveform from the oscillator with an output from the error amplifier, to form the on-width signal. Thus, the good output voltage characteristic is obtained even if the input voltage changes suddenly, which is suitable for the switching power source requiring the inserting and pulling out of the live wire.

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【発明の属する分野】本発明は、スイッチング電源に係わり、特に入力電圧変動時の出力電圧安定度の良い、制御方式に関するものである。 The present invention Field of the Invention relates to a switching power supply may otherwise output voltage stability during input voltage change, to a control system.

【0002】 [0002]

【従来の技術】通信機器用スイッチング電源は、活線挿抜等の必要があるため、入力電圧の急変時においても、 BACKGROUND OF THE INVENTION Switching power supply for communication devices, due to the need for such hot swapping, even when a sudden change in the input voltage,
出力電圧の安定度が要求される。 Stability of the output voltage is required. 図3はこの種の従来回路図、図6はその制御波形図で、この従来の電圧モードのスイッチング電源に於いては、入力急変により変化した出力電圧を、誤差増幅器12により検出し、制御を行うため高速で増幅率の高い増幅器が必要である。 Figure 3 is a conventional circuit diagram of this type, FIG. 6 is at its control waveforms, this is at the switching power supply of a conventional voltage mode, the output voltage varies with the input sudden change, detected by the error amplifier 12, controls the it requires a high amplification factor amplifier at high speed for performing. 即ち三角波発振器16は入力電圧の大小に係わらず一定傾斜の三角波形であり、該増幅器は入力電圧に即応したレベルの信号を送出することが求められる。 That triangular wave oscillator 16 is a triangular waveform regardless of the magnitude of the input voltage constant slope, the amplifier is able to deliver the level of the signal responsive to the input voltage is determined. しかしあまり高速にし、増幅率を高くすると、電源としての安定度が下がり、発振等を起こしてしまっていた。 But much to high speed, the higher the amplification rate, decreases the stability of as a power source, had gotten to cause the oscillation and the like.

【0003】また、図4は、他の従来回路図で所謂ピークカレントモードのスイッチング電源を示し、この回路に於いては、PWMコンパレータ13の一方の入力を、 [0003] Figure 4 shows a switching power supply of so-called peak current mode in another conventional circuit diagram, is In this circuit, one input of the PWM comparator 13,
抵抗4において検出するが、この検出した電流波形は電源のインダクタンス7等により決定され、図7に示すように入力電圧の大小により傾斜が変化し、ON幅を入力電圧により自動的に制御する。 Although detected in resistor 4, the detected current waveform is determined by the inductance 7 of the power supply or the like, the inclination is changed by the magnitude of the input voltage as shown in FIG. 7, automatically controlled by the input voltage ON width. それ故、ピークカレントモード方式は、入力電圧の急変特性は良い特性である。 Therefore, the peak current mode scheme, sudden change characteristics of the input voltage is a good characteristic.
しかし、軽負荷時の不安定、ON幅が50%を越えた場合の不安定、負荷短絡時等にON幅がゼロとならない等欠点があった。 However, instability at light loads, instability when the ON width exceeds 50%, ON width of load short-circuit or the like there is such disadvantage that does not become zero.

【0004】 [0004]

【発明が解決すべき課題】通信機器用スイッチング電源は、活線挿抜等の必要があるため、入力電圧の急変時においても、出力電圧の安定度が要求されるスイッチング電源において、本発明は、入力電圧急変特性が良く、軽負荷時、ON幅50%以上時の安定度の良い、スイッチング電源の制御方式を提供する。 An invention is to solve switching power supply for communication devices, due to the need for such hot swapping, even when a sudden change in the input voltage, the switching power supply stability of the output voltage is required, the present invention is, good input voltage sudden change characteristics, light load, good stability when ON width of 50% or more, to provide a control method of a switching power supply.

【0005】 [0005]

【課題を解決する手段】上記の課題を解決するため請求項1の発明はスイッチング素子のON幅信号により出力電圧を制御するスイッチング電源において、ON幅を決定するPWMコンパレータと、周波数一定、且つ入力電圧により三角波の傾斜が可変する発振器と、該出力電圧と基準電圧の差を増幅する誤差増幅器とを備え、該PW Means for Solving the Problems To solve the above problems the invention of claim 1 in a switching power supply to control the output voltage by the ON width signal of the switching element, and a PWM comparator to determine the ON width, constant frequency, and the input comprising an oscillator tilting of the triangular wave is varied by a voltage, and an error amplifier for amplifying a difference between the output voltage and the reference voltage, the PW
Mコンパレータは該発振器の出力波形と該誤差増幅器の出力とを比較してON幅信号を形成するようにした事を特徴とする。 M comparator, characterized in that it has to form a ON width signal by comparing the output of the output waveform and said error amplifier of the oscillator.

【0006】上記の課題を解決するため請求項2の発明は、スイッチング電源が一石式フォワードコンバータであることを特徴とする。 [0006] according to claim 2 for solving the above problems the invention is characterized in that the switching power supply is one transistor type forward converter.

【0007】又、上記の課題を解決するため請求項3の発明はスイッチング電源がフライバックコンバータであることを特徴とする。 [0007] The invention of claim 3 for solving the above problems is characterized in that the switching power supply is a flyback converter.

【0008】 [0008]

【実施の態様】図1は本発明の実施例であって、1は入力コンデンサ、2は電力変換用変圧器、3はスイッチング素子、4は電流検出用抵抗、5は整流用ダイオード、 Figure 1 [aspect of an A embodiment of the present invention, 1 is an input capacitor, 2 power conversion transformer, 3 switching elements, 4 denotes a current detection resistor 5 is a rectifying diode,
6は転流用ダイオード、7は平滑用チョーク、8は平滑用コンデンサ、9,10は出力電圧検出用抵抗、11は基準電圧、12は誤差増幅器、13はON幅を変調するPWMコンパレータである。 6 commutation diode, 7 smoothing choke, the smoothing capacitor 8, 9 and 10 are resistors for detecting output voltage, 11 a reference voltage, 12 the error amplifier, 13 is a PWM comparator to modulate the ON width. 又、17は入力電圧により、周波数は一定であるが、三角波の傾斜(振幅)を制御する入力電圧比例三角波発振器である。 Further, 17 by the input voltage, although the frequency is constant, an input voltage proportional triangular wave oscillator for controlling the triangular wave slope of the (amplitude).

【0009】図5はこの回路の制御波形図である。 [0009] FIG 5 is a control waveform diagram of the circuit. この基本動作は入力電圧が一定の場合、基準電圧11と出力電圧の誤差分を誤差増幅器12にて増幅し、その出力信号(ロ)と、入力電圧比例三角波発振器17の三角波(イ)をPWMコンパレータ13にて比較しスイッチ素子3をO If this basic operation input voltage is constant, the error of the reference voltage 11 and the output voltage is amplified by the error amplifier 12, PWM and the output signal (b), the input voltage proportional triangular wave oscillator 17 triangular wave (b) O the switch element 3 compared by the comparator 13
N−OFFし電力変換変圧器2により2次側に伝え、整流用ダイオード5,転流用ダイオード6、平滑用チョーク7と平滑用コンデンサ8により出力電圧が一定な直流電圧を供給する。 Carried by N-OFF to power converter transformer 2 on the secondary side, the rectifying diode 5 is supplied, the commutating diode 6, a constant DC voltage output voltage by the smoothing choke 7 and the smoothing capacitor 8.

【0010】本発明では入力電圧比例三角波発振器17 [0010] In the present invention, the input voltage proportional to the triangular wave oscillator 17
は、発振周波数は一定であるが、入力電圧により三角波の傾斜角度(又は振幅)を制御する発振器を用いている。 Is the oscillation frequency is constant, and using an oscillator for controlling the inclination angle of the triangular wave (or amplitude) by the input voltage. 即ち、入力電圧が高くなると、傾斜が大きくなり(振幅大)、入力電圧が低くなると傾斜角度が小さくなる(振幅小)様制御されている発振器である。 That is, when the input voltage increases, the inclination becomes large (the amplitude is large), and the inclination angle of the input voltage decreases is smaller is an oscillator which is (amplitude is small) like control. いま入力電圧が高くなった場合、図5の本回路波形の入力電圧大の三角波形イのように、三角波の傾斜が大きくなるため、誤差増幅器が変化しなくてもON幅を狭くし、出力電圧を一定にするよう制御される。 If now the input voltage is increased, as the input voltage sized triangular waveform b of the circuit waveform of FIG. 5, since the inclination of the triangular wave is large, and narrow the ON width without error amplifier is changed, the output It is controlled to the voltage constant. それ故良好な入力電圧急変特性が実現される。 Therefore good input voltage sudden change characteristics can be realized. 尚、三角波の傾斜の制御は一例として、抵抗とコンデンサを直列接続して入力端子間に接続し、又一定周期でオン、オフするスイッチ素子を上記コンデンサの両端に接続し該コンデンサの充放電特性を利用することにより容易に形成できる。 As an example the control of the slope of the triangular wave, a resistor and a capacitor connected in series is connected between the input terminals, and on a fixed cycle, the switching element is turned off to connect to both ends of the capacitor charge and discharge characteristics of the capacitor It can be easily formed by utilizing.

【0011】図2は本発明の他の実施例であり、上記実施例では一石式フォワードコンバータの例で説明したが、この実施例はスイッチング素子3のオン時に変圧器2にエネルギーを蓄積し、オフ時に直流出力を供給する所謂フライバックコンバータに適用したもので同様な効果が得られる。 [0011] Figure 2 shows another embodiment of the present invention, in the above embodiment was described using an example of one stone type forward converter, this embodiment stores energy in the transformer 2 during on of the switching device 3, similar effect obtained by applying the obtained supply so-called flyback converter a DC output at the time of off. また、ピークカレントモード制御のように、PWMコンパレータの信号として回路電流を使用しないため、軽負荷時の不安定、ON幅50%以上時の不安定等は無い。 Further, as the peak current mode control, because it does not use the circuit current as a signal of the PWM comparator, unstable at light loads, instability, etc. when ON width of 50% or more is not.

【0012】因みに表1に本発明回路(図1)と、従来回路(ピークカレントモード図4、電圧モード図3)を比較した入力電圧急変時の出力電圧特性を示すが、ピークカレントモード制御と同様の良い特性が得られている事が分かる。 [0012] Incidentally the present invention circuit (FIG. 1) in Table 1, the conventional circuit (peak current mode 4, the voltage mode Figure 3) shows the output voltage characteristics at the time of input voltage sudden change of the comparison, and peak current mode control it can be seen that the same good characteristics are obtained.

【表1】 [Table 1] (測定は48V入力3.3V3Aの電源にて、入力電圧36 (Measured at the power of 48V input 3.3V3A, input voltage 36
v→48v変化時間10usecにて測定) v → 48v change time measured by 10usec)

【0013】 [0013]

【発明の効果】以上の説明から明らかなように本発明によれば活線挿抜の必要なスイッチング電源に於いて、入力電圧急変時、軽負荷時等において良好な出力電圧特性が得られ又、高速、高増幅率の増幅器を使用することがないので経済的効果も大きい。 In the required switching power supply of the above, according to the apparent in the present invention hot plug from the description, according to the present invention, when the input voltage changes suddenly, good output voltage characteristics at light load or the like is obtained also fast, greater economic effect because there is no use of high amplification factor of the amplifier.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本発明の一実施回路図 An exemplary circuit diagram of the present invention; FIG

【図2】本発明の他の実施例回図 Another embodiment of times diagram of the present invention; FIG

【図3】従来の回路図 FIG. 3 is a conventional circuit diagram

【図4】従来の回路図 [Figure 4] conventional circuit diagram

【図5】本発明の実施例回路図(図1)の制御波形図 Control waveform diagram of FIG. 5 embodiment circuit diagram of the present invention (FIG. 1)

【図6】従来回路(図3)の制御波形図 [6] control waveform diagram of a conventional circuit (FIG. 3)

【図7】従来回路(図4)の制御波形図 [7] control waveform diagram of a conventional circuit (FIG. 4)

【符号の説明】 DESCRIPTION OF SYMBOLS

1: 入力コンデンサ 2: 電力変換用変圧器 3: スイッチング素子 4: 電流検出用抵抗 5: 整流用ダイオード 6: 転流用ダイオード 7: 平滑用チョーク 8: 平滑用コンデンサ 9、10: 出力電圧検出用抵抗 11: 基準電圧 12: 誤差増幅器 13: PWMコンパレータ 17: 入力電圧比例三角波発振器 1: the input capacitor 2: power converter transformer 3: Switching element 4: current detecting resistor 5: rectifying diode 6: commutating diode 7: smoothing choke 8: smoothing capacitor 9 and 10: the output voltage detecting resistor 11: reference voltage 12: error amplifier 13: PWM comparator 17: input voltage proportional triangular wave oscillator

Claims (3)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】スイッチング素子のON幅信号により出力電圧を制御するスイッチング電源において、ON幅を決定するPWMコンパレータと、周波数一定、且つ入力電圧により三角波の傾斜が可変する発振器と、該出力電圧と基準電圧の差を増幅する誤差増幅器とを備え、該PW 1. A switching power supply to control the output voltage by the ON width signal of the switching element, and a PWM comparator to determine the ON width, and oscillator frequency constant and triangular wave slope by the input voltage is variable, and the output voltage and a differential amplifier for amplifying a difference between the reference voltage, the PW
    Mコンパレータは該発振器の出力波形と該誤差増幅器の出力とを比較してON幅信号を形成するようにした事を特徴とするスイッチング電源。 M comparator switching power supply, characterized in that was to form the ON width signal by comparing the output of the output waveform of the oscillator and said error amplifier.
  2. 【請求項2】スイッチング電源が一石式フォワードコンバータであることを特徴とする請求項1のスイッチング電源。 2. A switching power supply according to claim 1, the switching power supply characterized in that it is a single-transistor type forward converter.
  3. 【請求項3】スイッチング電源がフライバックコンバータであることを特徴とする請求項1のスイッチング電源。 3. A switching power supply according to claim 1, the switching power supply is characterized by a flyback converter.
JP2001050531A 2001-02-26 2001-02-26 Switching power source Pending JP2002252979A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6963190B2 (en) 2003-05-14 2005-11-08 Taiyo Yuden Co., Ltd. Power supply apparatus
JP2007082316A (en) * 2005-09-14 2007-03-29 Fuji Electric Device Technology Co Ltd Dc/dc converter
US7202650B2 (en) 2002-11-12 2007-04-10 O2Micro International Limited Controller for DC to DC converter
CN100525083C (en) 2004-01-07 2009-08-05 奥特蓝星技术股份有限公司 Power supply rejection for pulse width modulated amplifiers and automatic gain control
JP2011188602A (en) * 2010-03-08 2011-09-22 Kyosan Electric Mfg Co Ltd Voltage conversion circuit and voltage conversion method
US9059632B2 (en) 2008-03-24 2015-06-16 O2Micro, Inc. Controllers for DC to DC converters

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7202650B2 (en) 2002-11-12 2007-04-10 O2Micro International Limited Controller for DC to DC converter
US6963190B2 (en) 2003-05-14 2005-11-08 Taiyo Yuden Co., Ltd. Power supply apparatus
CN100525083C (en) 2004-01-07 2009-08-05 奥特蓝星技术股份有限公司 Power supply rejection for pulse width modulated amplifiers and automatic gain control
JP2007082316A (en) * 2005-09-14 2007-03-29 Fuji Electric Device Technology Co Ltd Dc/dc converter
JP4682763B2 (en) * 2005-09-14 2011-05-11 富士電機システムズ株式会社 Dc / dc converter
US9059632B2 (en) 2008-03-24 2015-06-16 O2Micro, Inc. Controllers for DC to DC converters
JP2011188602A (en) * 2010-03-08 2011-09-22 Kyosan Electric Mfg Co Ltd Voltage conversion circuit and voltage conversion method

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