JP2006277760A - Power supply circuit and power supply voltage supplying method - Google Patents

Power supply circuit and power supply voltage supplying method Download PDF

Info

Publication number
JP2006277760A
JP2006277760A JP2006136545A JP2006136545A JP2006277760A JP 2006277760 A JP2006277760 A JP 2006277760A JP 2006136545 A JP2006136545 A JP 2006136545A JP 2006136545 A JP2006136545 A JP 2006136545A JP 2006277760 A JP2006277760 A JP 2006277760A
Authority
JP
Japan
Prior art keywords
voltage
circuit
constant voltage
power supply
constant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2006136545A
Other languages
Japanese (ja)
Inventor
Toshihisa Nagata
敏久 永田
Koji Yoshii
宏治 吉井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP2006136545A priority Critical patent/JP2006277760A/en
Publication of JP2006277760A publication Critical patent/JP2006277760A/en
Pending legal-status Critical Current

Links

Images

Landscapes

  • Direct Current Feeding And Distribution (AREA)
  • Continuous-Control Power Sources That Use Transistors (AREA)
  • Dc-Dc Converters (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power supply circuit and power supply voltage supplying method capable of reducing an input voltage of a circuit for generating a second constant voltage and making a mounting area small by reducing power consumption of the circuit for generating the second constant voltage. <P>SOLUTION: The power supply circuit comprises a first constant voltage circuit 2 for applying voltage step-down to a power supply voltage VDD from a direct current power supply 10, generating a prescribed constant voltage V1 and outputting the constant voltage V1, and a second constant voltage circuit 3 for applying voltage step-down to the constant voltage V1 outputted from the first constant voltage circuit 2, generating a prescribed constant voltage V2 and outputting the constant voltage V2, wherein a reference voltage generation circuit 23 in the second constant voltage circuit 3 is caused to operate with the power supply voltage VDD from the direct current power supply 10 as the power source. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、本発明は、低電圧負荷用の電源回路に関し、特に低電圧で動作する複数の負荷回路に対して異なる特性の電源の供給を行う電源回路に関する。   The present invention relates to a power supply circuit for a low voltage load, and more particularly to a power supply circuit that supplies power having different characteristics to a plurality of load circuits operating at a low voltage.

近年、環境対策上、省エネルギーが求められており、その結果、電子回路における動作電圧の低電圧化が進み、特に電池を使用した機器において該低電圧化が顕著である。また、１つの装置内において、電源に要求される特性が回路機能ごとに多様化しており、何種類もの電源電圧や、必要な電源の特性が異なるケースが増えてきている。このような用途に応えるため、従来の電源回路１００は、図４に示すような構成になっていた。   In recent years, energy conservation has been demanded for environmental measures, and as a result, the operation voltage of electronic circuits has been lowered, and the reduction in voltage is particularly remarkable in devices using batteries. In addition, the characteristics required for the power supply are diversified for each circuit function in one apparatus, and the number of types of power supply voltages and necessary power supply characteristics are increasing. In order to meet such an application, the conventional power supply circuit 100 has a configuration as shown in FIG.

図４における電源回路１００は、電池等の直流電源１１０から供給された直流電源を、第１の定電圧回路１０１で安定化させた後、複数の第２の定電圧回路１０２ａ〜１０２ｃで、対応する負荷回路（図示せず）が要求する直流電源を生成して出力する構成をなしていた。例えば、第１の定電圧回路１０１には効率のよいＤＣ／ＤＣコンバータ使用して、直流電源１１０からの電源電圧ＶＤＤを目的の電源電圧に近い電圧まで降圧させる。   The power supply circuit 100 shown in FIG. 4 uses a plurality of second constant voltage circuits 102a to 102c after the DC power supplied from a DC power supply 110 such as a battery is stabilized by the first constant voltage circuit 101. The load circuit (not shown) to generate and output the direct current power source required. For example, an efficient DC / DC converter is used for the first constant voltage circuit 101, and the power supply voltage VDD from the DC power supply 110 is stepped down to a voltage close to the target power supply voltage.

ここで、第２の定電圧回路１０２ａ〜１０２ｃに接続される負荷回路がアナログ回路であれば、第２の定電圧回路１０２ａ〜１０２ｃにはリプルやノイズの少ないシリーズレギュレータを使用する。これに対して、第２の定電圧回路１０２ａ〜１０２ｃに接続される負荷回路がデジタル回路であれば、第２の定電圧回路１０２ａ〜１０２ｃにはＤＣ／ＤＣコンバータを使用するといったように、第２の定電圧回路１０２ａ〜１０２ｃには、接続される負荷回路に応じた種類の定電圧回路を使用していた。   Here, if the load circuit connected to the second constant voltage circuits 102a to 102c is an analog circuit, a series regulator with less ripple and noise is used for the second constant voltage circuits 102a to 102c. On the other hand, if the load circuit connected to the second constant voltage circuits 102a to 102c is a digital circuit, a DC / DC converter is used for the second constant voltage circuits 102a to 102c. For the second constant voltage circuits 102a to 102c, a constant voltage circuit of a type corresponding to the connected load circuit is used.

ここで、図５は、第２の定電圧回路１０２ａ〜１０２ｃで使用されるシリーズレギュレータの回路例をそれぞれ示している。第２の定電圧回路１０２ａ〜１０２ｃで使用される基準電圧Ｖｒを生成して出力する基準電圧発生回路１０５の電源には、図５から分かるように、シリーズレギュレータの入力電圧か、又は出力電圧から供給されていた。電圧の高い基準電圧を必要とする場合は、図５（ａ）のように、基準電圧発生回路１０５の電源は、シリーズレギュレータの入力側から供給されることが望ましい。   Here, FIG. 5 shows circuit examples of series regulators used in the second constant voltage circuits 102a to 102c, respectively. As can be seen from FIG. 5, the power supply of the reference voltage generation circuit 105 that generates and outputs the reference voltage Vr used in the second constant voltage circuits 102a to 102c is derived from the input voltage of the series regulator or the output voltage. Had been supplied. When a high reference voltage is required, as shown in FIG. 5A, it is desirable that the power of the reference voltage generation circuit 105 is supplied from the input side of the series regulator.

しかし、このようにした場合、基準電圧発生回路１０５に供給される電源電圧は、通常安定化されていないため変動の大きいものとなり、基準電圧発生回路１０５から出力される基準電圧の安定度がやや低下するという問題があった。これに対して、図５（ｂ）のように基準電圧発生回路１０５の電源をシリーズレギュレータの出力側から供給する場合は、基準電圧発生回路１０５から出力される基準電圧の安定度は向上するが、シリーズレギュレータの出力電圧が基準電圧発生回路１０５を作動させるために必要な電圧以上であることが要求される。   However, in this case, the power supply voltage supplied to the reference voltage generation circuit 105 is usually not stabilized and thus varies greatly, and the stability of the reference voltage output from the reference voltage generation circuit 105 is slightly higher. There was a problem of lowering. On the other hand, when the power supply of the reference voltage generation circuit 105 is supplied from the output side of the series regulator as shown in FIG. 5B, the stability of the reference voltage output from the reference voltage generation circuit 105 is improved. The output voltage of the series regulator is required to be equal to or higher than the voltage necessary for operating the reference voltage generation circuit 105.

なお、従来において、２つの昇圧回路を直列に接続し、電圧レベルの絶対値が大きくて電圧変動の少ない電圧を生成する半導体集積回路があった（例えば、特許文献１参照。）。また、昇圧回路と降圧回路が直列に接続され、該昇圧回路及び降圧回路で使用される基準電圧は、基準電圧源６で入力端子に入力された電圧を使用して生成される定電圧型スイッチング電源回路があった（例えば、特許文献２参照。）。
特開２００１−１６９５３８号公報 特開平１−６４５５８号公報 Conventionally, there has been a semiconductor integrated circuit in which two booster circuits are connected in series to generate a voltage with a large absolute value of voltage level and a small voltage fluctuation (see, for example, Patent Document 1). Further, a booster circuit and a step-down circuit are connected in series, and a reference voltage used in the step-up circuit and the step-down circuit is generated by using a voltage input to an input terminal by a reference voltage source 6. There was a power supply circuit (for example, refer to Patent Document 2).
JP 2001-169538 A JP-A-1-64558

ここで、図６は、基準電圧発生回路１０５の回路例を示しており、図６（ａ）及び図６（ｂ）はツェナーダイオードを使用した場合を示しており、図６（ｃ）は、バンドギャップを使用した場合を示している。低い基準電圧を得るためには、図６（ｂ）で示すように、ツェナーダイオードで得られる定電圧を抵抗で分圧して得ることができる。また、図６（ｃ）のようなバンドギャップ電圧を利用した基準電圧発生回路はＩＣ化が容易であり、ＩＣとして市販(例えば製品名ＴＬ４３１)されているものもある。   Here, FIG. 6 shows a circuit example of the reference voltage generation circuit 105, FIGS. 6A and 6B show a case where a Zener diode is used, and FIG. The case where a band gap is used is shown. In order to obtain a low reference voltage, as shown in FIG. 6B, a constant voltage obtained by a Zener diode can be obtained by dividing by a resistor. In addition, a reference voltage generation circuit using a band gap voltage as shown in FIG. 6C can be easily formed as an IC, and some ICs are commercially available (for example, product name TL431).

図６で示したような基準電圧発生回路１０５を安定させて動作させるためには、ツェナーダイオードを使用した図６（ａ）及び図６（ｂ）の場合では５Ｖ以上の電源電圧が、図６（ｃ）のトランジスタのバンドギャップ電圧を使用した場合でも３Ｖ以上の電源電圧が必要であった。更に、基準電圧発生回路１０５の電源は、できるだけ電圧が安定してリプルやノイズの少ないものである必要があった。   In order to stably operate the reference voltage generation circuit 105 as shown in FIG. 6, in the case of FIGS. 6A and 6B using a Zener diode, a power supply voltage of 5 V or more is required. Even when the band gap voltage of the transistor (c) is used, a power supply voltage of 3 V or more is required. Further, the power source of the reference voltage generation circuit 105 has to be as stable as possible with little ripple and noise.

しかし、第２の定電圧回路１０２ａ〜１０２ｃの各出力電圧を低下、例えば３Ｖから１Ｖ台まで低下させる必要がある場合、第２の定電圧回路１０２ａ〜１０２ｃの出力電圧では、基準電圧発生回路１０５を作動させることができないという問題があった。   However, when it is necessary to lower the output voltages of the second constant voltage circuits 102a to 102c, for example, from 3V to 1V, the reference voltage generation circuit 105 is used for the output voltages of the second constant voltage circuits 102a to 102c. There was a problem that could not be operated.

また、第２の定電圧回路１０２ａ〜１０２ｃの各入力電圧を第１の定電圧回路１０１からそれぞれ供給される場合、できる限り第２の定電圧回路１０２ａ〜１０２ｃでの電力消費を少なくするため、第１の定電圧回路１０１は、第２の定電圧回路１０２ａ〜１０２ｃの出力電圧に近い電圧を入力電圧として供給するのが望ましかった。このため、例えば作動電圧が３Ｖの負荷回路を作動させるためには、該負荷回路に電源を供給する第２の定電圧回路の入力電圧には約３.３Ｖの電圧が、作動電圧が２Ｖの負荷回路を作動させるためには、該負荷回路に電源を供給する第２の定電圧回路の入力電圧には約２.３Ｖの電圧が入力されるようにする必要があった。   Further, when the input voltages of the second constant voltage circuits 102a to 102c are supplied from the first constant voltage circuit 101, respectively, in order to reduce the power consumption in the second constant voltage circuits 102a to 102c as much as possible, It was desirable that the first constant voltage circuit 101 supplies a voltage close to the output voltage of the second constant voltage circuits 102a to 102c as an input voltage. For this reason, for example, in order to operate a load circuit having an operating voltage of 3V, the input voltage of the second constant voltage circuit that supplies power to the load circuit is about 3.3V, and the operating voltage is 2V. In order to operate the load circuit, it is necessary to input a voltage of about 2.3 V to the input voltage of the second constant voltage circuit that supplies power to the load circuit.

このため、図５（ａ）の第２の定電圧回路のような入力側から電源が供給される基準電圧発生回路に対しても作動させることができなくなり、作動させることができたとしても安定した基準電圧を得ることができなかった。また、基準電圧発生回路が作動するための十分な電圧を、第１の定電圧回路１０１から第２の定電圧回路に供給すると、第２の定電圧回路での消費電力が増大するという問題が発生する。このため、第２の定電圧回路での発熱が増加し、分散した電源回路ごとに大きな実装スペースが必要になるという問題があった。   For this reason, the reference voltage generating circuit to which power is supplied from the input side such as the second constant voltage circuit of FIG. 5A cannot be operated, and even if it can be operated, it is stable. The obtained reference voltage could not be obtained. Further, if a sufficient voltage for operating the reference voltage generation circuit is supplied from the first constant voltage circuit 101 to the second constant voltage circuit, the power consumption in the second constant voltage circuit increases. appear. For this reason, there is a problem that heat generation in the second constant voltage circuit increases and a large mounting space is required for each dispersed power supply circuit.

更に、第１の定電圧回路１０１がＤＣ／ＤＣコンバータのようなスイッチング方式の定電圧回路の場合は、出力電圧にリプルや、高周波ノイズが重畳されている。このような出力電圧が電源として基準電圧発生回路に直接供給されると、基準電圧発生回路からの基準電圧にもリプルや高周波ノイズが重畳し、第２の定電圧回路からの出力電圧も不安定なものになるという問題があった。   Further, when the first constant voltage circuit 101 is a switching type constant voltage circuit such as a DC / DC converter, ripples and high frequency noise are superimposed on the output voltage. When such an output voltage is directly supplied to the reference voltage generation circuit as a power source, ripples and high frequency noise are also superimposed on the reference voltage from the reference voltage generation circuit, and the output voltage from the second constant voltage circuit is also unstable. There was a problem of becoming something.

本発明は、上記のような問題を解決するためになされたものであり、第２の定電圧回路における基準電圧発生回路の電源を第１の定電圧回路の入力電圧を供給している直流電源から得るようにしたことから、第２の定電圧回路の入力電圧を低下させることができ、第２の定電圧回路での消費電力を小さくして実装面積を小さくすることができる電源回路及び電源電圧供給方法を得ることを目的とする。   The present invention has been made to solve the above-described problem, and a DC power supply that supplies a reference voltage generation circuit power supply in a second constant voltage circuit to an input voltage of the first constant voltage circuit. Therefore, the power supply circuit and the power supply that can reduce the input voltage of the second constant voltage circuit, reduce the power consumption in the second constant voltage circuit, and reduce the mounting area. The object is to obtain a voltage supply method.

この発明に係る電源回路は、電源電圧を所定の第１の定電圧に変換して出力する第１の定電圧回路と、該第１の定電圧回路からの出力電圧をあらかじめ設定された定電圧に変換して出力する少なくとも１つの第２の定電圧回路とを備える電源回路において、
前記第２の定電圧回路は、所定の第２の基準電圧を生成して出力する第２の基準電圧発生回路を有し、
前記第１の定電圧回路の出力電圧は、前記第２の基準電圧発生回路が安定動作する電圧以下であり、前記第２の基準電圧発生回路は、前記電源電圧を電源にして作動するものである。 A power supply circuit according to the present invention includes a first constant voltage circuit that converts a power supply voltage into a predetermined first constant voltage and outputs the first constant voltage, and an output voltage from the first constant voltage circuit. In a power supply circuit comprising at least one second constant voltage circuit that converts and outputs to
The second constant voltage circuit includes a second reference voltage generation circuit that generates and outputs a predetermined second reference voltage,
The output voltage of the first constant voltage circuit is equal to or lower than a voltage at which the second reference voltage generation circuit operates stably, and the second reference voltage generation circuit operates using the power supply voltage as a power source. is there.

また、この発明に係る電源電圧供給方法は、電源電圧を所定の第１の定電圧に降圧し、該第１の定電圧を所定の第２の定電圧に降圧して負荷に出力する電源電圧供給方法において、
前記第２の定電圧を所定の分圧比で分圧し、
該分圧電圧が、基準電圧に等しくなるように、前記第２の定電圧を制御して前記負荷に供給するようにした。 In the power supply voltage supply method according to the present invention, the power supply voltage is stepped down to a predetermined first constant voltage, and the first constant voltage is stepped down to a predetermined second constant voltage and output to the load. In the supply method,
Dividing the second constant voltage at a predetermined voltage dividing ratio;
The second constant voltage is controlled and supplied to the load so that the divided voltage becomes equal to the reference voltage.

本発明の電源回路によれば、第２の定電圧回路における第２の基準電圧発生回路が、第１の定電圧回路の入力電圧である電源電圧を電源にして作動するようにしたことから、第２の定電圧回路の入力電圧を低下させることができるため、第２の定電圧回路での消費電力を小さくすることができ実装面積を小さくすることができる。   According to the power supply circuit of the present invention, the second reference voltage generation circuit in the second constant voltage circuit is operated using the power supply voltage that is the input voltage of the first constant voltage circuit as a power supply. Since the input voltage of the second constant voltage circuit can be reduced, the power consumption in the second constant voltage circuit can be reduced and the mounting area can be reduced.

また、本発明の電源電圧供給方法によれば、前記第２の定電圧を所定の分圧比で分圧し、該分圧電圧が、基準電圧に等しくなるように、前記第２の定電圧を制御して前記負荷に供給するようにしたことから、第１の定電圧を第２の定電圧に降圧する際の該第１の定電圧を低下させることができるため、第２の定電圧を生成するときの消費電力を小さくすることができ、実装面積を小さくすることができる。   According to the power supply voltage supply method of the present invention, the second constant voltage is divided at a predetermined voltage dividing ratio, and the second constant voltage is controlled so that the divided voltage becomes equal to the reference voltage. Since the first constant voltage can be lowered when the first constant voltage is stepped down to the second constant voltage, the second constant voltage is generated. In this case, power consumption can be reduced and the mounting area can be reduced.

次に、図面に示す実施の形態に基づいて、本発明を詳細に説明する。
第１の実施の形態．
図１は、本発明の第１の実施の形態における電源回路の例を示した図である。なお、図１では、１つの第２の定電圧回路を有する降圧型の電源回路を例にして示し、第２の定電圧回路にシリーズレギュレータを使用した場合を例にして示している。
図１において、電源回路１は、電池等の直流電源１０からの電源電圧ＶＤＤを所定の定電圧Ｖ１に降圧する第１の定電圧回路２と、該第１の定電圧回路２から出力された定電圧Ｖ１を所定の定電圧Ｖ２に降圧して負荷回路（図示せず）に出力する第２の定電圧回路３とで構成されている。 Next, the present invention will be described in detail based on the embodiments shown in the drawings.
First embodiment.
FIG. 1 is a diagram showing an example of a power supply circuit according to the first embodiment of the present invention. In FIG. 1, a step-down power supply circuit having one second constant voltage circuit is shown as an example, and a case where a series regulator is used for the second constant voltage circuit is shown as an example.
In FIG. 1, a power supply circuit 1 outputs a first constant voltage circuit 2 that steps down a power supply voltage VDD from a DC power supply 10 such as a battery to a predetermined constant voltage V <b> 1 and the first constant voltage circuit 2. It is composed of a second constant voltage circuit 3 that steps down the constant voltage V1 to a predetermined constant voltage V2 and outputs it to a load circuit (not shown).

第１の定電圧回路２は、例えばスイッチングレギュレータで構成されており、入力端ＩＮ１に電源電圧ＶＤＤが入力され、生成した定電圧Ｖ１を出力端ＯＵＴ１から第２の定電圧回路２の入力端ＩＮ２に出力する。
図２は、第１の定電圧回路２をスイッチングレギュレータで形成した場合の回路例を示した図である。
図２における第１の定電圧回路２において、基準電圧発生回路３１は、直流電源１０からの電源電圧ＶＤＤを電源として動作し、所定の基準電圧Ｖｒ１を生成して出力する。 The first constant voltage circuit 2 is composed of, for example, a switching regulator. The power supply voltage VDD is input to the input terminal IN1, and the generated constant voltage V1 is output from the output terminal OUT1 to the input terminal IN2 of the second constant voltage circuit 2. Output to.
FIG. 2 is a diagram showing a circuit example when the first constant voltage circuit 2 is formed of a switching regulator.
In the first constant voltage circuit 2 in FIG. 2, the reference voltage generation circuit 31 operates using the power supply voltage VDD from the DC power supply 10 as a power supply, and generates and outputs a predetermined reference voltage Vr1.

また、抵抗３２及び３３は、出力端ＯＵＴ１から出力された電圧を分圧して分圧電圧Ｖｄ１を生成して出力し、誤差増幅器３４は、該分圧電圧Ｖｄ１と基準電圧Ｖｒ１との電圧差に応じた電圧を出力する。比較器３５は、三角波発生回路３６から出力された所定の三角波と、誤差増幅器３４の出力電圧との電圧比較を行い、該比較結果に応じた２値の信号をＰＭＯＳトランジスタからなるスイッチングトランジスタ３７のゲートに出力する。スイッチングトランジスタ３７は、比較器３５からの出力信号に応じてスイッチングを行う。スイッチングトランジスタ３７から出力された信号は、フライホールダイオードをなすダイオード３８、コイル３９及びコンデンサ４０で平滑されて出力端ＯＵＴ１から定電圧Ｖ１として出力される。   The resistors 32 and 33 divide the voltage output from the output terminal OUT1 to generate and output a divided voltage Vd1, and the error amplifier 34 determines the voltage difference between the divided voltage Vd1 and the reference voltage Vr1. The corresponding voltage is output. The comparator 35 performs a voltage comparison between the predetermined triangular wave output from the triangular wave generating circuit 36 and the output voltage of the error amplifier 34, and outputs a binary signal corresponding to the comparison result of the switching transistor 37 comprising a PMOS transistor. Output to the gate. The switching transistor 37 performs switching according to the output signal from the comparator 35. The signal output from the switching transistor 37 is smoothed by the diode 38 forming a fly-hole diode, the coil 39, and the capacitor 40, and output from the output terminal OUT1 as a constant voltage V1.

次に、図１において、第２の定電圧回路３は、ＰＭＯＳトランジスタからなる電圧制御用トランジスタ２１と、該電圧制御用トランジスタ２１の動作制御を行う誤差増幅器２２と、所定の基準電圧Ｖｒ２を生成して出力する基準電圧発生回路２３と、電圧制御用トランジスタ２１から出力される電圧を分圧する抵抗２４，２５とを備えたシリーズレギュレータで構成されている。   Next, in FIG. 1, the second constant voltage circuit 3 generates a voltage control transistor 21 composed of a PMOS transistor, an error amplifier 22 for controlling the operation of the voltage control transistor 21, and a predetermined reference voltage Vr2. The reference voltage generating circuit 23 that outputs the voltage and the resistors 24 and 25 that divide the voltage output from the voltage control transistor 21 are configured as a series regulator.

第２の定電圧回路３において、電圧制御用トランジスタ２１は、入力端ＩＮ２と出力端ＯＵＴ２との間に接続されており、抵抗２４と２５の直列回路が出力端ＯＵＴ２と接地電圧ＧＮＤとの間に接続されている。誤差増幅器２２の反転入力端には基準電圧発生回路２３からの基準電圧Ｖｒ２が入力されており、誤差増幅器２２の非反転入力端には、出力端ＯＵＴ２から出力された電圧が抵抗２４及び２５で分圧された分圧電圧Ｖｄ２が入力されている。誤差増幅器２２は、分圧電圧Ｖｄ２が基準電圧Ｖｒ２になるように電圧制御用トランジスタ２１の動作制御を行う。ここで、基準電圧発生回路２３は、直流電源１０からの電源電圧ＶＤＤを電源にして動作しており、誤差増幅器２２は、第１の定電圧回路２からの定電圧Ｖ１を電源として動作している。   In the second constant voltage circuit 3, the voltage control transistor 21 is connected between the input terminal IN2 and the output terminal OUT2, and a series circuit of resistors 24 and 25 is connected between the output terminal OUT2 and the ground voltage GND. It is connected to the. The reference voltage Vr2 from the reference voltage generation circuit 23 is input to the inverting input terminal of the error amplifier 22, and the voltage output from the output terminal OUT2 is input to the non-inverting input terminal of the error amplifier 22 through resistors 24 and 25. The divided voltage Vd2 is inputted. The error amplifier 22 controls the operation of the voltage control transistor 21 so that the divided voltage Vd2 becomes the reference voltage Vr2. Here, the reference voltage generation circuit 23 operates using the power supply voltage VDD from the DC power supply 10 as a power supply, and the error amplifier 22 operates using the constant voltage V1 from the first constant voltage circuit 2 as a power supply. Yes.

このようにすることにより、例えば第２の定電圧回路３の出力電圧が３Ｖ以下であり、第２の定電圧回路３の入力電圧が３.３Ｖであっても、基準電圧発生回路２３の電源は、第１の定電圧回路２の入力電圧である例えば６Ｖの電源電圧ＶＤＤが直接供給されるため、基準電圧発生回路２３を作動させるのに十分な電源電圧を供給することができる。このことから、第２の定電圧回路３は、出力する定電圧Ｖ２に電圧制御用トランジスタ２１のソース・ドレイン間電圧を加えた値以上の入力電圧が入力端ＩＮ２に入力されれば、安定した定電圧Ｖ２を出力することができる。   By doing so, for example, even if the output voltage of the second constant voltage circuit 3 is 3V or less and the input voltage of the second constant voltage circuit 3 is 3.3V, the power supply of the reference voltage generation circuit 23 Since, for example, a power supply voltage VDD of 6 V, which is an input voltage of the first constant voltage circuit 2, is directly supplied, a power supply voltage sufficient to operate the reference voltage generation circuit 23 can be supplied. From this, the second constant voltage circuit 3 is stable if an input voltage equal to or greater than the value obtained by adding the source-drain voltage of the voltage control transistor 21 to the output constant voltage V2 is input to the input terminal IN2. A constant voltage V2 can be output.

例えば、第２の定電圧回路３の出力端ＯＵＴ２から出力される電流が１００ｍＡである場合、電圧制御用トランジスタ２１のソース・ドレイン間電圧０.１〜０.２Ｖ位であることから、定電圧Ｖ２が１.５Ｖとした場合、第２の定電圧回路３は、入力端ＩＮ２に入力される電圧が１.６〜１.７Ｖ以上であれば安定した定電圧Ｖ２を出力することができる。このように、第１の定電圧回路２の出力電圧は、第２の定電圧回路３が定電圧Ｖ２を生成して出力するために必要とする最小入力電圧になるようにすればよい。   For example, when the current output from the output terminal OUT2 of the second constant voltage circuit 3 is 100 mA, the voltage between the source and the drain of the voltage control transistor 21 is about 0.1 to 0.2 V. When V2 is 1.5 V, the second constant voltage circuit 3 can output a stable constant voltage V2 as long as the voltage input to the input terminal IN2 is 1.6 to 1.7 V or higher. In this way, the output voltage of the first constant voltage circuit 2 may be set to the minimum input voltage required for the second constant voltage circuit 3 to generate and output the constant voltage V2.

また、第１の定電圧回路２が、ＤＣ／ＤＣコンバータのようなスイッチングレギュレータである場合、第１の定電圧回路２の出力電圧に含まれるリプルや高周波のスイッチングノイズが第２の定電圧回路３における基準電圧発生回路２３に入り込まないため、更に第２の定電圧回路３の出力電圧を安定させることができる。   In addition, when the first constant voltage circuit 2 is a switching regulator such as a DC / DC converter, ripples and high-frequency switching noise included in the output voltage of the first constant voltage circuit 2 are the second constant voltage circuit. 3, the output voltage of the second constant voltage circuit 3 can be further stabilized.

次に、図１では第２の定電圧回路が１つである場合を例にして説明したが、複数の第２の定電圧回路を備えるようにしてもよく、図３は、このようにした場合の電源回路１の例を示した概略のブロック図である。なお、図３では、３つの第２の定電圧回路を有する降圧型の電源回路を例にして示しているが、本発明は、これに限定するものではなく、複数の第２の定電圧回路を備える場合に適用することができる。また、図３では、図１と同じものは同じ符号で示し、ここではその説明を省略する。
図３において、電源回路１は、第１の定電圧回路２と、該第１の定電圧回路２から出力された定電圧Ｖ１を所定の定電圧Ｖ２ａ〜Ｖ２ｃに降圧して対応する負荷回路（図示せず）に出力する第２の定電圧回路３ａ〜３ｃとで構成されている。 Next, FIG. 1 illustrates an example in which there is one second constant voltage circuit. However, a plurality of second constant voltage circuits may be provided, and FIG. It is the schematic block diagram which showed the example of the power supply circuit 1 in the case. In FIG. 3, a step-down power supply circuit having three second constant voltage circuits is shown as an example. However, the present invention is not limited to this, and a plurality of second constant voltage circuits are provided. It can be applied in the case of comprising. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted here.
In FIG. 3, a power supply circuit 1 includes a first constant voltage circuit 2 and a load circuit (corresponding to stepping down the constant voltage V1 output from the first constant voltage circuit 2 to predetermined constant voltages V2a to V2c ( And the second constant voltage circuits 3a to 3c that output to the output (not shown).

第２の定電圧回路３ａ〜３ｃは、図１の第２の定電圧回路３と同じ回路構成をそれぞれなしており、第２の定電圧回路３との相違点は、基準電圧発生回路から出力される基準電圧が異なるか否かにある。第２の定電圧回路３ａは、所定の基準電圧Ｖｒａを生成して出力する基準電圧発生回路２３ａを、第２の定電圧回路３ｂは、所定の基準電圧Ｖｒｂを生成して出力する基準電圧発生回路２３ｂを、第２の定電圧回路３ｃは、所定の基準電圧Ｖｒｃを生成して出力する基準電圧発生回路２３ｃをそれぞれ備えている。   The second constant voltage circuits 3a to 3c have the same circuit configuration as that of the second constant voltage circuit 3 of FIG. 1, and the difference from the second constant voltage circuit 3 is that the output from the reference voltage generation circuit. The reference voltage to be used is different. The second constant voltage circuit 3a generates a reference voltage generation circuit 23a that generates and outputs a predetermined reference voltage Vra, and the second constant voltage circuit 3b generates a reference voltage generation circuit that generates and outputs a predetermined reference voltage Vrb. The circuit 23b and the second constant voltage circuit 3c are each provided with a reference voltage generation circuit 23c that generates and outputs a predetermined reference voltage Vrc.

基準電圧発生回路２３ａ〜２３ｃの各電源入力端ＩＮ３ａ〜ＩＮ３ｃには、直流電源１０からの電源電圧ＶＤＤがそれぞれ入力され、基準電圧発生回路２３ａ〜２３ｃは、直流電源１０からの電源電圧ＶＤＤを電源にしてそれぞれ動作する。また、第１の定電圧回路２の出力電圧は、第２の定電圧回路３ａ〜３ｃの中で最も高い入力電圧を必要とする電圧に設定する。すなわち、第１の定電圧回路２の出力電圧は、各第２の定電圧回路３ａ〜３ｃが対応する定電圧Ｖ２ａ〜Ｖ２ｃを生成して出力するために必要とするそれぞれの最小入力電圧の最大値になるようにする。このようにして、第２の定電圧回路３ａ〜３ｃで消費される電力が最小になるようにする。   The power supply voltage VDD from the DC power supply 10 is input to the power supply input terminals IN3a to IN3c of the reference voltage generation circuits 23a to 23c, respectively. The reference voltage generation circuits 23a to 23c supply the power supply voltage VDD from the DC power supply 10 as a power source. Each works. The output voltage of the first constant voltage circuit 2 is set to a voltage that requires the highest input voltage among the second constant voltage circuits 3a to 3c. That is, the output voltage of the first constant voltage circuit 2 is the maximum of the minimum input voltage required for each of the second constant voltage circuits 3a to 3c to generate and output the corresponding constant voltage V2a to V2c. To be a value. In this way, the power consumed by the second constant voltage circuits 3a to 3c is minimized.

なお、前記説明では、第２の定電圧回路にシリーズレギュレータを使用した場合を例にして説明したが、接続される負荷回路に応じて第２の定電圧回路に図２で示したようなスイッチングレギュレータを使用してもよい。このようにした場合、スイッチングレギュレータにおける基準電圧発生回路は、直流電源１０からの電源電圧ＶＤＤを電源にしてそれぞれ動作するようにする。また、前記説明では、第１の定電圧回路２にスイッチングレギュレーションを使用した場合を例にして説明したが、本発明は、これに限定するものではなく、第１の定電圧回路２にシリーズレギュレータを使用してもよい。   In the above description, the case where the series regulator is used for the second constant voltage circuit has been described as an example. However, the switching as shown in FIG. 2 is applied to the second constant voltage circuit according to the connected load circuit. A regulator may be used. In this case, the reference voltage generation circuit in the switching regulator operates with the power supply voltage VDD from the DC power supply 10 as the power supply. In the above description, the case where the switching regulation is used for the first constant voltage circuit 2 has been described as an example. However, the present invention is not limited to this, and the first constant voltage circuit 2 includes a series regulator. May be used.

このように、本第１の実施の形態における電源回路は、直流電源１０からの電源電圧ＶＤＤを降圧して所定の定電圧Ｖ１を生成し出力する第１の定電圧回路２と、該第１の定電圧回路２から出力された定電圧Ｖ１を降圧して所定の定電圧を生成し出力する少なくとも１つの第２の定電圧回路からなり、該第２の定電圧回路における基準電圧発生回路が直流電源１０からの電源電圧ＶＤＤを電源として動作するようにした。このことから、第２の定電圧回路の入力電圧を低下させることができ、第２の定電圧回路での消費電力を少なくして実装面積を小さくすることができる。   As described above, the power supply circuit according to the first embodiment includes the first constant voltage circuit 2 that steps down the power supply voltage VDD from the DC power supply 10 to generate and output the predetermined constant voltage V1, and the first constant voltage circuit 2 The constant voltage circuit 1 includes at least one second constant voltage circuit that steps down the constant voltage V1 output from the constant voltage circuit 2 to generate and output a predetermined constant voltage, and a reference voltage generation circuit in the second constant voltage circuit is provided. The power supply voltage VDD from the DC power supply 10 is used as a power supply. As a result, the input voltage of the second constant voltage circuit can be reduced, the power consumption in the second constant voltage circuit can be reduced, and the mounting area can be reduced.

本発明の第１の実施の形態における電源回路の例を示した図である。It is the figure which showed the example of the power supply circuit in the 1st Embodiment of this invention. 図１における第１の定電圧回路２をスイッチングレギュレータで形成した場合の回路例を示した図である。It is the figure which showed the circuit example at the time of forming the 1st constant voltage circuit 2 in FIG. 1 with a switching regulator. 本発明の第１の実施の形態における電源回路の他の例を示した概略のブロック図である。It is the schematic block diagram which showed the other example of the power supply circuit in the 1st Embodiment of this invention. 従来の電源回路の例を示した概略のブロック図である。It is the schematic block diagram which showed the example of the conventional power supply circuit. 図４の第２の定電圧回路の回路例を示した図である。FIG. 5 is a diagram illustrating a circuit example of a second constant voltage circuit in FIG. 4. 図５の基準電圧発生回路１０５の回路例を示した図である。FIG. 6 is a diagram illustrating a circuit example of a reference voltage generation circuit 105 in FIG. 5.

符号の説明Explanation of symbols

１ 電源回路
２ 第１の定電圧回路
３，３ａ〜３ｃ 第２の定電圧回路
１０ 直流電源
２１ 電圧制御用トランジスタ
２２，３４ 誤差増幅器
２３，３１，２３ａ〜２３ｃ 基準電圧発生回路
２４，２５，３２，３３ 抵抗
３５ 比較器
３６ 三角波発生回路
３７ スイッチングトランジスタ
３８ ダイオード
３９ コイル
４０ コンデンサ
DESCRIPTION OF SYMBOLS 1 Power supply circuit 2 1st constant voltage circuit 3,3a-3c 2nd constant voltage circuit 10 DC power supply 21 Voltage control transistor 22,34 Error amplifier 23,31,23a-23c Reference voltage generation circuit 24,25,32 33 Resistor 35 Comparator 36 Triangular wave generation circuit 37 Switching transistor 38 Diode 39 Coil 40 Capacitor

Claims (2)

電源電圧を所定の第１の定電圧に変換して出力する第１の定電圧回路と、該第１の定電圧回路からの出力電圧をあらかじめ設定された定電圧に変換して出力する少なくとも１つの第２の定電圧回路とを備える電源回路において、
前記第２の定電圧回路は、所定の第２の基準電圧を生成して出力する第２の基準電圧発生回路を有し、
前記第１の定電圧回路の出力電圧は、前記第２の基準電圧発生回路が安定動作する電圧以下であり、前記第２の基準電圧発生回路は、前記電源電圧を電源にして作動することを特徴とする電源回路。 A first constant voltage circuit that converts a power supply voltage into a predetermined first constant voltage and outputs the first constant voltage; and at least one that converts an output voltage from the first constant voltage circuit into a preset constant voltage and outputs the voltage. In a power supply circuit comprising two second constant voltage circuits,
The second constant voltage circuit includes a second reference voltage generation circuit that generates and outputs a predetermined second reference voltage,
The output voltage of the first constant voltage circuit is equal to or lower than a voltage at which the second reference voltage generation circuit operates stably, and the second reference voltage generation circuit operates with the power supply voltage as a power source. A featured power supply circuit. 電源電圧を所定の第１の定電圧に降圧し、該第１の定電圧を所定の第２の定電圧に降圧して負荷に出力する電源電圧供給方法において、
前記第２の定電圧を所定の分圧比で分圧し、
該分圧電圧が、基準電圧に等しくなるように、前記第２の定電圧を制御して前記負荷に供給することを特徴とする電源電圧供給方法。
In a power supply voltage supply method for stepping down a power supply voltage to a predetermined first constant voltage, stepping down the first constant voltage to a predetermined second constant voltage and outputting the same to a load,
Dividing the second constant voltage at a predetermined voltage dividing ratio;
A power supply voltage supply method characterized in that the second constant voltage is controlled and supplied to the load so that the divided voltage becomes equal to a reference voltage.
JP2006136545A 2006-05-16 2006-05-16 Power supply circuit and power supply voltage supplying method Pending JP2006277760A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006136545A JP2006277760A (en) 2006-05-16 2006-05-16 Power supply circuit and power supply voltage supplying method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006136545A JP2006277760A (en) 2006-05-16 2006-05-16 Power supply circuit and power supply voltage supplying method

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
JP2005044122A Division JP3817569B2 (en) 2005-02-21 2005-02-21 Power circuit

Publications (1)

Publication Number Publication Date
JP2006277760A true JP2006277760A (en) 2006-10-12

Family

ID=37212388

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006136545A Pending JP2006277760A (en) 2006-05-16 2006-05-16 Power supply circuit and power supply voltage supplying method

Country Status (1)

Country Link
JP (1) JP2006277760A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008035694A (en) * 2006-06-30 2008-02-14 Semiconductor Energy Lab Co Ltd Semiconductor device
US8004254B2 (en) 2008-02-19 2011-08-23 Ricoh Company, Ltd. Power supply circuit
CN103187871A (en) * 2011-12-30 2013-07-03 北京谊安医疗系统股份有限公司 Power supply control device of magnetic valve flow in anaesthesia machine and method thereof
US8502417B2 (en) 2008-04-11 2013-08-06 Ricoh Company, Ltd. Power source device and output voltage changing method of the power source device
JP2013208766A (en) * 2012-03-30 2013-10-10 Brother Industries Ltd Image forming apparatus
JP2019007924A (en) * 2017-06-28 2019-01-17 株式会社デンソー Electronic device

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6464558A (en) * 1987-09-03 1989-03-10 Seiko Epson Corp Constant voltage type switching power source circuit
JPH08223796A (en) * 1995-02-07 1996-08-30 Nikon Corp Power circuit
JPH09179639A (en) * 1995-10-27 1997-07-11 Toko Inc Series control type regulator
JPH09233810A (en) * 1996-02-22 1997-09-05 Sony Corp Switching power supply circuit
JPH1173231A (en) * 1997-08-29 1999-03-16 Sharp Corp Dc stabilized power supply device
JP2000354365A (en) * 1999-06-07 2000-12-19 Sharp Corp Regulated dc power unit and optical medium equipment using the same
JP2001147726A (en) * 1999-09-06 2001-05-29 Seiko Instruments Inc Voltage regulator
JP2001282370A (en) * 2000-03-29 2001-10-12 Sharp Corp Stabilized direct current power source device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6464558A (en) * 1987-09-03 1989-03-10 Seiko Epson Corp Constant voltage type switching power source circuit
JPH08223796A (en) * 1995-02-07 1996-08-30 Nikon Corp Power circuit
JPH09179639A (en) * 1995-10-27 1997-07-11 Toko Inc Series control type regulator
JPH09233810A (en) * 1996-02-22 1997-09-05 Sony Corp Switching power supply circuit
JPH1173231A (en) * 1997-08-29 1999-03-16 Sharp Corp Dc stabilized power supply device
JP2000354365A (en) * 1999-06-07 2000-12-19 Sharp Corp Regulated dc power unit and optical medium equipment using the same
JP2001147726A (en) * 1999-09-06 2001-05-29 Seiko Instruments Inc Voltage regulator
JP2001282370A (en) * 2000-03-29 2001-10-12 Sharp Corp Stabilized direct current power source device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008035694A (en) * 2006-06-30 2008-02-14 Semiconductor Energy Lab Co Ltd Semiconductor device
US8004254B2 (en) 2008-02-19 2011-08-23 Ricoh Company, Ltd. Power supply circuit
US8502417B2 (en) 2008-04-11 2013-08-06 Ricoh Company, Ltd. Power source device and output voltage changing method of the power source device
CN103187871A (en) * 2011-12-30 2013-07-03 北京谊安医疗系统股份有限公司 Power supply control device of magnetic valve flow in anaesthesia machine and method thereof
CN103187871B (en) * 2011-12-30 2016-04-20 北京谊安医疗系统股份有限公司 The power control of electromagnetically operated valve flow and method in a kind of Anesthesia machine
JP2013208766A (en) * 2012-03-30 2013-10-10 Brother Industries Ltd Image forming apparatus
US9417592B2 (en) 2012-03-30 2016-08-16 Brother Kogyo Kabushiki Kaisha Image forming apparatus
JP2019007924A (en) * 2017-06-28 2019-01-17 株式会社デンソー Electronic device

Similar Documents

Publication Publication Date Title
EP1385074B1 (en) Power supplying method and apparatus capable of quickly responding to variations in input and output voltages to output a stable voltage
US7893667B2 (en) PWM power supply apparatus having a controlled duty ratio without causing overall system oscillation
JP5369750B2 (en) Power supply circuit and operation control method thereof
US6593725B1 (en) Feed-forward control for DC-DC converters
CN107305400B (en) Reference voltage generating circuit and DCDC converter having the same
JP4997122B2 (en) Power supply circuit and operation control method thereof
KR102216799B1 (en) Buck converter
CN108432112B (en) DC-DC converter and semiconductor integrated circuit for driving load
JP5152761B2 (en) Boost type switching power supply circuit
JP2006277760A (en) Power supply circuit and power supply voltage supplying method
JP2007014176A (en) Multiple-power supply circuit and multiple-power supply method
JP5176433B2 (en) Switching regulator and DC-DC converter using the switching regulator
JP3817569B2 (en) Power circuit
JP4673350B2 (en) DC power supply
JP6608866B2 (en) DC-DC converter
JP2009254110A (en) Step-up dc-dc converter and semiconductor integrated circuit for driving power supply
JP4328290B2 (en) Power supply circuit, semiconductor integrated circuit device, electronic apparatus, and control method for power supply circuit
JP4082708B2 (en) Low voltage output regulator IC and linear regulator IC, switching regulator IC, composite regulator IC using the circuit
JP6224365B2 (en) Power supply device and semiconductor device
JP2007236071A (en) Voltage conversion device and method
JP2003180073A (en) Power supply circuit
JP2008086165A (en) Power supply unit
JP2007236051A (en) Switching regulator
JP5062188B2 (en) POWER CIRCUIT, ELECTRONIC DEVICE, SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE, AND POWER CIRCUIT CONTROL METHOD
US10250118B1 (en) PWM mode boost switching regulator with programmable pulse skip mode

Legal Events

Date Code Title Description
A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20090818

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20091006

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20091124

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100224

A911 Transfer of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20100316

A912 Removal of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A912

Effective date: 20100416