JP2007094970A - Voltage supply circuit - Google Patents

Voltage supply circuit Download PDF

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JP2007094970A
JP2007094970A JP2005286667A JP2005286667A JP2007094970A JP 2007094970 A JP2007094970 A JP 2007094970A JP 2005286667 A JP2005286667 A JP 2005286667A JP 2005286667 A JP2005286667 A JP 2005286667A JP 2007094970 A JP2007094970 A JP 2007094970A
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transistor
circuit
voltage
time constant
resistor
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Michiya Hosono
倫也 細野
Yuukai Fukuhara
悠介 福原
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Toko Inc
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Toko Inc
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Priority to TW095135092A priority patent/TWI327691B/en
Priority to KR1020060095521A priority patent/KR100813486B1/en
Publication of JP2007094970A publication Critical patent/JP2007094970A/en
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/08—Regulating voltage or current wherein the variable is dc
    • G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
    • G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
    • G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
    • G05F3/205—Substrate bias-voltage generators
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/08—Regulating voltage or current wherein the variable is dc
    • G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
    • G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
    • G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
    • G05F3/22—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations wherein the transistors are of the bipolar type only
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/08—Regulating voltage or current wherein the variable is dc
    • G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
    • G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
    • G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
    • G05F3/26—Current mirrors
    • G05F3/265—Current mirrors using bipolar transistors only

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Nonlinear Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Continuous-Control Power Sources That Use Transistors (AREA)
  • Control Of Electrical Variables (AREA)
  • Measurement Of Predetermined Time Intervals (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage supply circuit which charges a capacitor quickly which constitutes a time constant circuit when voltage supply starts and easily adjusts a quantity of bias to be supplied for a transistor. <P>SOLUTION: On an input side of a time constant circuit 6 equipped with a series circuit of a resistor R0 and a capacitor C0 provided is the voltage supply circuit 7a of a series regulator type. Inside the voltage supply circuit 7a provided are: a first transistor Q1 connected between an input terminal IN of the voltage supply circuit and the time constant circuit 6; a second transistor Q2 for performing current mirror operation with the first transistor Q1; a third transistor Q3 which connects to the resistor R0 of the time constant circuit 6 its main current passage in parallel; and a bias circuit for supplying the third transistor Q3 with bias in accordance with current to be supplied by the second transistor Q2 or, to be specific, a resistor R3. More preferably, to the resistor R0 of the time constant circuit 6, a diode Q5 is connected in parallel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、ＲＣ時定数回路やフィルタ回路を介して所定の電圧を供給するための電圧発生回路に関し、時定数回路内に設けられたコンデンサの充電を急速に行うことで、それらが設置された装置全体の起動動作を高速で行えるようにするための技術に関するものである。   The present invention relates to a voltage generation circuit for supplying a predetermined voltage via an RC time constant circuit or a filter circuit, and by rapidly charging a capacitor provided in the time constant circuit, they are installed. The present invention relates to a technique for enabling the startup operation of the entire apparatus at high speed.

一般的な電子機器は、例えば信号処理装置、表示装置、駆動装置など、様々な装置部分の集合体として成り立っている。一部の装置が動作状態にある時に他の装置が起動あるいは動作停止をすると、電源電圧が変動したり、誤動作を誘発する恐れのあるノイズが動作中の装置に侵入してしまうという事態が起こり得る。このため、各装置の入力側に個別に電圧安定化回路を設ける、特に電圧値の安定化が求められる回路箇所にはＲＣ時定数回路（フィルタ、積分回路とも言う）を設ける、などの対策が必要であった。   A general electronic device is configured as an assembly of various device parts such as a signal processing device, a display device, and a driving device. When some devices are in operation, when other devices are started or stopped, the power supply voltage may fluctuate or noise that may cause malfunctions may enter the operating device. obtain. For this reason, measures such as individually providing a voltage stabilization circuit on the input side of each device, especially providing an RC time constant circuit (also referred to as a filter or an integration circuit) at a circuit location where the stabilization of the voltage value is required. It was necessary.

図２は、電子機器内における電源と負荷装置と安定化回路とフィルタの位置関係の一例を示している。
図２において、電源１の高電位側端子はＰｃｈ−ＭＯＳ型のパワートランジスタ３の主電流路を介して負荷装置２の一端に接続され、電源1の低電位側端子及び負荷装置２の他端は共にグランドに接続されている。パワートランジスタ３のゲートはトランジスタ４の主電流路を介してグランドに接続され、トランジスタ４のゲートは誤差増幅器５の信号出力端子に接続されている。 FIG. 2 shows an example of the positional relationship among the power source, the load device, the stabilization circuit, and the filter in the electronic device.
In FIG. 2, the high potential side terminal of the power source 1 is connected to one end of the load device 2 through the main current path of the Pch-MOS type power transistor 3, and the low potential side terminal of the power source 1 and the other end of the load device 2. Are both connected to ground. The gate of the power transistor 3 is connected to the ground via the main current path of the transistor 4, and the gate of the transistor 4 is connected to the signal output terminal of the error amplifier 5.

誤差増幅器５の反転入力端子（−）はパワートランジスタ３と負荷装置２の共通接続点に接続され、誤差増幅器５の非反転入力端子（＋）は時定数回路６に接続されている。
ここで、時定数回路６は抵抗Ｒ０とコンデンサＣ０の直列回路からなり、抵抗Ｒ０とコンデンサＣ０のそれぞれの一端が誤差増幅器５の非反転入力端子（＋）に共通接続され、コンデンサＣ０の他端はグランドに接続され、抵抗Ｒ０の他端は電圧発生回路７の出力端子ＯＵＴに接続されている。そして電圧発生回路７の入力端子ＩＮは、電源１の高電位側端子に接続されている。 The inverting input terminal (−) of the error amplifier 5 is connected to the common connection point of the power transistor 3 and the load device 2, and the non-inverting input terminal (+) of the error amplifier 5 is connected to the time constant circuit 6.
Here, the time constant circuit 6 is composed of a series circuit of a resistor R0 and a capacitor C0, and one end of each of the resistor R0 and the capacitor C0 is commonly connected to the non-inverting input terminal (+) of the error amplifier 5 and the other end of the capacitor C0. Is connected to the ground, and the other end of the resistor R0 is connected to the output terminal OUT of the voltage generating circuit 7. The input terminal IN of the voltage generation circuit 7 is connected to the high potential side terminal of the power supply 1.

この図２では、パワートランジスタ３、トランジスタ４、誤差増幅器５、時定数回路６、電圧発生回路７がシリーズレギュレータ・タイプの電圧安定化回路を構成し、電圧発生回路７から時定数回路６を介して供給される電圧ＶR2が安定化目標としての基準電圧に相当する。このため電源１の電源電圧ＶD が変動したとしても、その変動量が所定の限界値よりも小さく、かつ緩慢であれば、負荷装置２に供給される供給電圧ＶS は電圧発生回路７から時定数回路６を介して供給される電圧ＶR2にほぼ等しい大きさに安定化される。 In FIG. 2, the power transistor 3, the transistor 4, the error amplifier 5, the time constant circuit 6, and the voltage generation circuit 7 constitute a series regulator type voltage stabilization circuit, and the voltage generation circuit 7 passes through the time constant circuit 6. The voltage V R2 supplied in this way corresponds to a reference voltage as a stabilization target. Therefore, even if the power supply voltage V D of the power supply 1 fluctuates, if the fluctuation amount is smaller than a predetermined limit value and is slow, the supply voltage V S supplied to the load device 2 is supplied from the voltage generation circuit 7. The voltage is stabilized substantially equal to the voltage V R2 supplied via the time constant circuit 6.

一方、電源電圧ＶD の変動が非常に急峻である場合、あるいは高周波ノイズなどが重畳された場合には、電圧発生回路７の内部構成にも依るが、電圧発生回路７の出力電圧ＶR1にノイズが生じる可能性が有る。このような場合、時定数回路６がノイズを濾波するフィルタとして機能するため、誤差増幅器５の非反転入力端子（＋）の位置における電圧Ｖ＋（＝ＶR2）はノイズ成分が少ないものとなる。その結果、電源電圧ＶD に大きなノイズが重畳されても、供給電圧ＶS はノイズの少ない安定した値を維持する事になる。 On the other hand, when the fluctuation of the power supply voltage V D is very steep or when high frequency noise is superimposed, the output voltage V R1 of the voltage generation circuit 7 depends on the internal configuration of the voltage generation circuit 7. Noise may occur. In such a case, since the time constant circuit 6 functions as a filter for filtering noise, the voltage V + (= V R2 ) at the position of the non-inverting input terminal (+) of the error amplifier 5 has a small noise component. As a result, even if large noise is superimposed on the power supply voltage V D , the supply voltage V S maintains a stable value with little noise.

ところで、負荷装置２に供給される供給電圧ＶS のノイズ成分を少なくするには、時定数回路６を構成する抵抗Ｒ０の抵抗値とコンデンサＣ０の静電容量の少なくとも一方を充分に大きくし、電圧ＶR2に含まれるノイズを少なくすれば良い。しかし、抵抗Ｒ０の抵抗値やコンデンサＣ０の静電容量を大きくすると、図３中の曲線（ａ）（＝太線）のように、時定数回路６から誤差増幅器５に供給される電圧ＶR2の「ゼロボルトから規定電圧に到達するまでの時間」が長くなってしまう。負荷装置２の起動／停止が電源１からの電源電圧ＶD の供給／遮断によって行われるとすると、電源１からの電圧供給が開始されてから負荷装置２に供給される電圧ＶS が所定の値に達するまでの時間も長くなり、負荷装置２の起動が遅れてしまう。 By the way, in order to reduce the noise component of the supply voltage V S supplied to the load device 2, at least one of the resistance value of the resistor R0 and the capacitance of the capacitor C0 constituting the time constant circuit 6 is sufficiently increased, The noise included in the voltage V R2 may be reduced. However, when the resistance value of the resistor R0 and the capacitance of the capacitor C0 are increased, the voltage V R2 supplied from the time constant circuit 6 to the error amplifier 5 as shown by the curve (a) (= thick line) in FIG. “Time to reach the specified voltage from zero volts” becomes longer. Assuming that the load device 2 is started / stopped by supplying / cutting off the power supply voltage V D from the power source 1, the voltage V S supplied to the load device 2 after the voltage supply from the power source 1 is started is predetermined. The time until the value is reached also becomes long, and the activation of the load device 2 is delayed.

従って、負荷装置２に対してノイズの少ない電圧の供給が要求され、なおかつ負荷装置２の迅速な起動が要求される場合には、図４に示すように、（１）起動時にオン状態となるスイッチＳ１を抵抗Ｒ０に対して並列接続する、あるいは（２）起動時にオン状態となるスイッチＳ２を電源ラインＶccとコンデンサＣ０の一端の間に接続する、といった対策が必要となっていた。ちなみに、（１）の対策は電圧発生回路７自体に充分な電流供給能力がある場合に主に使用され、（２）の対策は電圧発生回路７自体に充分な電流供給能力が無い場合に使用される。（特許文献１参照）
特開平１１−０５１９８１号 Therefore, when the load device 2 is required to supply a voltage with less noise and the load device 2 is required to be activated quickly, as shown in FIG. 4, (1) the device is turned on at the time of activation. It is necessary to take measures such as connecting the switch S1 in parallel to the resistor R0, or (2) connecting the switch S2 that is turned on at the time of startup between the power supply line Vcc and one end of the capacitor C0. Incidentally, the measure (1) is mainly used when the voltage generation circuit 7 itself has sufficient current supply capability, and the measure (2) is used when the voltage generation circuit 7 itself does not have sufficient current supply capability. Is done. (See Patent Document 1)
JP-A-11-051981

上で紹介した（１）と（２）の対策で重要なのは、コンデンサＣ０の端子間電圧が低い時にはスイッチＳ１、Ｓ２をオンにし、コンデンサＣ０の充電が終了した後にはスイッチＳ１、Ｓ２オフさせることである。具体的に、抵抗Ｒ０に対してダイオードを並列接続すると、そのダイオードは、抵抗Ｒ０を流れる電流とコンデンサＣ０の端子間電圧に応じて自律的にオン、オフするスイッチＳ１として使用することができる。また、電源ラインＶccとコンデンサＣ０の間にトランジスタの主電流路を接続し、当該トランジスタの制御端子（＝ベース）を抵抗Ｒ０の他端に接続すると、そのトランジスタは、抵抗Ｒ０を流れる電流とコンデンサＣ０の端子間電圧に応じて自律的にオン、オフするスイッチＳ２として使用することができる。   What is important in the countermeasures (1) and (2) introduced above is that the switches S1 and S2 are turned on when the voltage across the capacitor C0 is low, and the switches S1 and S2 are turned off after the charging of the capacitor C0 is completed. It is. Specifically, when a diode is connected in parallel to the resistor R0, the diode can be used as the switch S1 that is autonomously turned on and off according to the current flowing through the resistor R0 and the voltage across the capacitor C0. Further, when a main current path of a transistor is connected between the power supply line Vcc and the capacitor C0, and the control terminal (= base) of the transistor is connected to the other end of the resistor R0, the transistor has a current and a capacitor flowing through the resistor R0. It can be used as a switch S2 that turns on and off autonomously according to the voltage between terminals of C0.

しかし、スイッチＳ１としてのダイオードを抵抗Ｒ０に並列接続した場合については、ダイオードに生じる順方向降下電圧がコンデンサＣ０への電流供給に抵抗する要因となる。このため、コンデンサＣ０の迅速な充電という面では未だ改善の余地が有る。一方、スイッチＳ２としてのトランジスタを電源ラインＶccとコンデンサＣ０の間に接続し、そのベースを抵抗Ｒ０の所定位置に接続した場合については、抵抗Ｒ０の抵抗値は主に時定数回路６に要求される特性によって決定されてしまう。このため、ターンオン、ターンオフ、オン状態維持の各時点でトランジスタに供給すべきバイアス量の調整が難しいといった問題があった。   However, when the diode as the switch S1 is connected in parallel to the resistor R0, the forward voltage drop generated in the diode becomes a factor that resists current supply to the capacitor C0. For this reason, there is still room for improvement in terms of quick charging of the capacitor C0. On the other hand, when the transistor as the switch S2 is connected between the power supply line Vcc and the capacitor C0 and its base is connected to a predetermined position of the resistor R0, the resistance value of the resistor R0 is mainly required by the time constant circuit 6. Will be determined by the characteristics. For this reason, there is a problem that it is difficult to adjust the bias amount to be supplied to the transistor at each time of turn-on, turn-off, and on-state maintenance.

そこで本発明は、電圧供給が開始された時に時定数回路を構成するコンデンサの充電を迅速に行え、なおかつトランジスタに供給すべきバイアス量の調整が容易な電圧供給回路を提供することを目的とする。   Accordingly, an object of the present invention is to provide a voltage supply circuit that can quickly charge a capacitor constituting a time constant circuit when voltage supply is started and that can easily adjust a bias amount to be supplied to a transistor. .

上記課題を解決するための本発明は、抵抗とコンデンサを含む時定数回路を介して時定数回路の出力側に設けられた機能回路に所定の電圧を供給するための電圧供給回路において、 時定数回路に電圧・電流を供給するように、入力端子と時定数回路の間に設けられた第１のトランジスタと、 その制御端子が第１のトランジスタの制御端子と共通接続され、その主電流路に第１のトランジスタを通過する電流に応じた電流を流すように構成された第２のトランジスタと、 その主電流路が時定数回路を構成する抵抗に並列接続された第３のトランジスタと、 第２のトランジスタの主電流路を通過する電流の供給を受けて第３のトランジスタの制御端子にバイアスを供給するバイアス回路とを具備することを特徴とする。更に好ましくは、時定数回路を構成する抵抗に対して並列接続されたダイオードを具備することを特徴とする。   In order to solve the above problems, the present invention provides a voltage supply circuit for supplying a predetermined voltage to a functional circuit provided on the output side of a time constant circuit via a time constant circuit including a resistor and a capacitor. The first transistor provided between the input terminal and the time constant circuit and the control terminal thereof are commonly connected to the control terminal of the first transistor so as to supply voltage and current to the circuit, and the main current path A second transistor configured to flow a current according to a current passing through the first transistor, a third transistor whose main current path is connected in parallel to a resistor forming a time constant circuit, And a bias circuit for supplying a bias to the control terminal of the third transistor by receiving a current passing through the main current path of the transistor. More preferably, it comprises a diode connected in parallel to the resistor constituting the time constant circuit.

時定数回路を構成する抵抗の両端を、電圧供給開始時にオン状態となる第３のトランジスタで短絡するようにしたため、順方向降下電圧のような電流流通に対する抵抗要因が小さく、迅速に時定数回路内のコンデンサを充電できる。
電圧供給開始時に抵抗の両端を短絡する第３のトランジスタに対し、第２のトランジスタとそこから電流供給を受けるバイアス回路からバイアスを供給するようにしたため、時定数回路の抵抗の設定値に関係なくバイアス量を設定できる。そして、第２のトランジスタを通過する電流の大きさ、供給電流に対するバイアス回路からのバイアス供給量、そして必要に応じて抵抗に並列接続したダイオードの順方向降下電圧（オン電圧）、を相互に調整する事により、ターンオン、オフ、そしてオン状態維持の各時点での第３のトランジスタに供給すべきバイアス量の調整が容易に行える。 Since both ends of the resistor constituting the time constant circuit are short-circuited by the third transistor that is turned on at the start of voltage supply, the resistance factor with respect to current flow such as a forward voltage drop is small, and the time constant circuit is quickly The capacitor inside can be charged.
Since the bias is supplied from the second transistor and the bias circuit that receives current from the third transistor that short-circuits both ends of the resistor at the start of voltage supply, regardless of the set value of the resistance of the time constant circuit. The amount of bias can be set. Then, the magnitude of the current passing through the second transistor, the bias supply amount from the bias circuit with respect to the supply current, and the forward drop voltage (ON voltage) of the diode connected in parallel with the resistor are adjusted as necessary. By doing so, it is possible to easily adjust the bias amount to be supplied to the third transistor at each point of turn-on, off, and maintaining the on-state.

抵抗とコンデンサの直列回路を備える時定数回路の入力側にシリーズレギュレータ型の電圧供給回路を設ける。ここで電圧供給回路の内部には、電圧供給回路の入力端子と時定数回路の間に接続された第１のトランジスタと、第１のトランジスタとカレントミラー動作を行う第２のトランジスタと、時定数回路の抵抗にその主電流路を並列接続した第３のトランジスタと、第２のトランジスタから供給される電流に応じて第３のトランジスタにバイアスを供給するバイアス回路、具体的には抵抗、を設ける。更に望ましくは、時定数回路の抵抗に対してダイオードを並列接続する。   A series regulator type voltage supply circuit is provided on the input side of a time constant circuit including a series circuit of a resistor and a capacitor. Here, the voltage supply circuit includes a first transistor connected between the input terminal of the voltage supply circuit and the time constant circuit, a second transistor performing current mirror operation with the first transistor, and a time constant. A third transistor having a main current path connected in parallel to a circuit resistor, and a bias circuit for supplying a bias to the third transistor according to a current supplied from the second transistor, specifically, a resistor, are provided. . More preferably, a diode is connected in parallel to the resistance of the time constant circuit.

電圧供給回路から時定数回路に対して電圧の供給が開始された時、時定数回路のコンデンサの端子間電圧が低いとダイオードが導通する。この時、抵抗とダイオードの双方を流れる電流がコンデンサに流れ込み、第１のトランジスタを通過する電流は抵抗単独の時よりも大きくなる。第１のトランジスタを通過する電流が大きくなると第２のトランジスタを通過する電流も大きくなり、第３のトランジスタがオンする。オン状態のトランジスタ素子の主電流路に現れる電気抵抗は極めて低く、そこに生じる電位差もダイオードの順方向降下電圧よりも低いため、コンデンサは急速に充電される。   When voltage supply is started from the voltage supply circuit to the time constant circuit, the diode becomes conductive when the voltage across the terminals of the capacitor of the time constant circuit is low. At this time, the current flowing through both the resistor and the diode flows into the capacitor, and the current passing through the first transistor is larger than when the resistor alone is used. When the current passing through the first transistor increases, the current passing through the second transistor also increases and the third transistor is turned on. Since the electric resistance appearing in the main current path of the transistor element in the on state is very low, and the potential difference generated there is also lower than the forward drop voltage of the diode, the capacitor is rapidly charged.

コンデンサの充電が進み、その端子間電圧が上昇すると、やがて第３のトランジスタはオン状態を維持できなくなる。具体的に、コンデンサの端子間電圧がほぼ規定の電圧値にまで高まると第３のトランジスタはオフ状態に移行する。以後、第３のトランジスタは、コンデンサの端子間電圧が高い値を維持する限りオフ状態を維持する。このようにして第３のトランジスタは、実質的に時定数回路を構成するコンデンサの端子間電圧に応じてオン、オフすることになる。   When charging of the capacitor proceeds and the voltage between the terminals rises, the third transistor can no longer be kept on. Specifically, when the voltage between the terminals of the capacitor increases to a substantially specified voltage value, the third transistor shifts to an off state. Thereafter, the third transistor remains off as long as the voltage across the capacitor maintains a high value. In this way, the third transistor is turned on / off in accordance with the voltage across the terminals of the capacitor constituting the time constant circuit.

電圧供給開始時に時定数回路のコンデンサの充電を迅速に行えるようにした、本発明による電圧供給回路の回路を図１に示した。ここで図１の回路は、図２中の電圧発生回路７と時定数回路６に相当する部分を抜き出して示しており、電圧発生回路７ａを次のように接続構成している。
入力端子ＩＮと出力端子ＯＵＴの間にトランジスタＱ１の主電流路を接続し、トランジスタＱ１のベースはトランジスタＱ４の主電流路を介してグランドに接続されている。トランジスタＱ４のベースは誤差増幅器ＡＭＰの信号出力端子に接続され、誤差増幅器ＡＭＰの非反転入力端子（＋）はバンドギャップリファレンス回路ＢＧに接続されている。出力端子ＯＵＴとグランドの間に抵抗Ｒ１とＲ２の直列回路が接続され、抵抗Ｒ１とＲ２の共通接続点は誤差増幅器ＡＭＰの反転入力端子（−）に接続されている。 FIG. 1 shows a circuit of a voltage supply circuit according to the present invention that can quickly charge a capacitor of a time constant circuit at the start of voltage supply. Here, the circuit of FIG. 1 shows a portion corresponding to the voltage generation circuit 7 and the time constant circuit 6 in FIG. 2, and the voltage generation circuit 7a is connected and configured as follows.
The main current path of the transistor Q1 is connected between the input terminal IN and the output terminal OUT, and the base of the transistor Q1 is connected to the ground via the main current path of the transistor Q4. The base of the transistor Q4 is connected to the signal output terminal of the error amplifier AMP, and the non-inverting input terminal (+) of the error amplifier AMP is connected to the band gap reference circuit BG. A series circuit of resistors R1 and R2 is connected between the output terminal OUT and the ground, and a common connection point of the resistors R1 and R2 is connected to an inverting input terminal (−) of the error amplifier AMP.

トランジスタＱ１とベース同士、エミッタ同士がそれぞれ共通接続されたトランジスタＱ２を設け、トランジスタＱ２のコレクタをバイアス回路としての抵抗Ｒ３の一端に接続する。抵抗Ｒ３の他端はグランドに接続し、抵抗Ｒ３の一端をトランジスタＱ３のベースに接続する。トランジスタＱ３の主電流路が時定数回路６内の抵抗Ｒ０に対して並列接続状態になるように、そのエミッタを抵抗Ｒ０の一端に、そのコレクタを抵抗Ｒ０の他端に接続する。そして、コレクタ、ベース間を短絡したトランジスタＱ５を設け、トランジスタＱ５のエミッタを抵抗Ｒ０の一端に、コレクタを抵抗Ｒ０の他端に接続する。   The transistor Q1, the base, and the transistor Q2 in which the emitters are commonly connected are provided, and the collector of the transistor Q2 is connected to one end of a resistor R3 as a bias circuit. The other end of the resistor R3 is connected to the ground, and one end of the resistor R3 is connected to the base of the transistor Q3. The emitter is connected to one end of the resistor R0 and the collector is connected to the other end of the resistor R0 so that the main current path of the transistor Q3 is in parallel connection with the resistor R0 in the time constant circuit 6. Then, a transistor Q5 in which the collector and the base are short-circuited is provided, and the emitter of the transistor Q5 is connected to one end of the resistor R0 and the collector is connected to the other end of the resistor R0.

以上のような構成とした電圧発生回路７ａは以下のような動作をする。
先ず、入力端子ＩＮに電圧が供給されると、バンドギャップリファレンス回路ＢＧと誤差増幅器ＡＭＰが動作状態となる。ところで、電圧発生回路７ａの内部において、トランジスタＱ１、誤差増幅器ＡＭＰ、バンドギャップリファレンス回路ＢＧ、および抵抗Ｒ１とＲ２はシリーズレギュレータの回路構成となっている。このため、動作状態となったバンドギャップリファレンス回路ＢＧは、室温で１．２６Ｖ前後の値を示す安定度の極めて高いＢＧ電圧信号を発生させ、一方、動作状態となった誤差増幅器ＡＭＰは、抵抗Ｒ１とＲ２の共通接続点の電圧がバンドギャップリファレンス回路ＢＧから供給されるＢＧ電圧信号に等しくなるように、トランジスタＱ１を駆動する事になる。 The voltage generating circuit 7a configured as described above operates as follows.
First, when a voltage is supplied to the input terminal IN, the bandgap reference circuit BG and the error amplifier AMP are in operation. Incidentally, in the voltage generation circuit 7a, the transistor Q1, the error amplifier AMP, the band gap reference circuit BG, and the resistors R1 and R2 have a circuit configuration of a series regulator. For this reason, the bandgap reference circuit BG in the operating state generates a very stable BG voltage signal indicating a value of about 1.26 V at room temperature, while the error amplifier AMP in the operating state has a resistance The transistor Q1 is driven so that the voltage at the common connection point of R1 and R2 is equal to the BG voltage signal supplied from the band gap reference circuit BG.

時定数回路６のコンデンサＣ０が未充電状態であり、その端子間電圧が低い状態であると、当然、誤差増幅器ＡＭＰはトランジスタＱ１の通過電流を大きくするようにトランジスタＱ１を駆動する。この時、時定数回路６の抵抗Ｒ０の端子間には大きな電位差が生じる。この電位差はダイオードとして動作するトランジスタＱ５のオン電圧を上回る大きさとなるため、トランジスタＱ５が導通し、トランジスタＱ５を介してコンデンサＣ０に大きな充電電流が供給されるようになる。   When the capacitor C0 of the time constant circuit 6 is in an uncharged state and the voltage between the terminals is low, the error amplifier AMP naturally drives the transistor Q1 so as to increase the passing current of the transistor Q1. At this time, a large potential difference is generated between the terminals of the resistor R0 of the time constant circuit 6. Since this potential difference is larger than the ON voltage of the transistor Q5 operating as a diode, the transistor Q5 becomes conductive, and a large charging current is supplied to the capacitor C0 via the transistor Q5.

トランジスタＱ５に電流が流れると、トランジスタＱ１には抵抗Ｒ０単独の時よりも大きな電流が流れるようになり、トランジスタＱ１とカレントミラー回路を構成するように接続されたトランジスタＱ２にも大きな電流が流れる。トランジスタＱ２を通過した電流は抵抗Ｒ３の一端とトランジスタＱ３のベースに供給され、その結果、トランジスタＱ３はオンする。オンしたトランジスタＱ３の主電流路は電気抵抗の極めて低い状態となり、コンデンサＣ０の充電を迅速に行わせる。   When a current flows through the transistor Q5, a larger current flows through the transistor Q1 than when the resistor R0 alone, and a large current also flows through the transistor Q2 connected to form a current mirror circuit with the transistor Q1. The current passing through the transistor Q2 is supplied to one end of the resistor R3 and the base of the transistor Q3. As a result, the transistor Q3 is turned on. The main current path of the transistor Q3 that is turned on has a very low electric resistance, and the capacitor C0 is quickly charged.

コンデンサＣ０の充電が進み、その端子間電圧（すなわち電圧ＶR2）が規定の値に近づくと、Ｑ１、Ｑ４、ＡＭＰ、ＢＧ、Ｒ１、Ｒ２からなる回路部分のシリーズレギュレータとしての動作により、トランジスタＱ１を通過する電流が絞られる。この時、トランジスタＱ２の通過電流も同時に絞られ、トランジスタＱ３のエミッタの位置の電位上昇とベースの位置の電位低下が同時進行する。すると、トランジスタＱ３に供給されるバイアスは低下し、やがてトランジスタＱ３はオフ状態に移行することになる。
以上のようにして、トランジスタＱ３は、コンデンサＣ０の端子間電圧とトランジスタＱ１を通過する電流に応じてオン、オフすることになる。 When the charging of the capacitor C0 progresses and the voltage between the terminals (that is, the voltage V R2 ) approaches a specified value, the transistor Q1 operates as a series regulator of the circuit portion composed of Q1, Q4, AMP, BG, R1, and R2. The current passing through is reduced. At this time, the passing current of the transistor Q2 is simultaneously reduced, and the potential increase at the emitter position of the transistor Q3 and the potential decrease at the base position proceed simultaneously. Then, the bias supplied to the transistor Q3 decreases, and the transistor Q3 is eventually turned off.
As described above, the transistor Q3 is turned on / off according to the voltage across the capacitor C0 and the current passing through the transistor Q1.

この図１の回路においては、トランジスタＱ３がオン状態となった時、そのコレクタ、エミッタ間に現れる電位差が、ダイオード素子の順方向降下電圧やコレクタ、ベース間が短絡されたトランジスタＱ５のコレクタ、エミッタ間の電位差よりも低くなる。このため、時定数回路６の抵抗Ｒ０にダイオードを接続するだけの対策（先に説明した（１）の対策の具体例）よりも迅速にコンデンサＣ０を充電できる。そして、トランジスタＱ３にバイアスを供給するための抵抗Ｒ３とトランジスタＱ２は、その抵抗値とトランジスタのサイズ（＝通過電流の大きさ）を時定数回路６の抵抗値や特性に関係なく設定できる。このため、トランジスタＱ３のターンオン時、ターンオフ時のバイアス供給量、オン状態維持の時のバイアス供給量の調整が容易となる。   In the circuit of FIG. 1, when the transistor Q3 is turned on, the potential difference appearing between its collector and emitter is caused by the forward drop voltage of the diode element and the collector and emitter of the transistor Q5 shorted between the collector and base. It becomes lower than the potential difference between. For this reason, the capacitor C0 can be charged more quickly than a measure by simply connecting a diode to the resistor R0 of the time constant circuit 6 (specific example of the measure (1) described above). The resistance R3 and the transistor Q2 for supplying a bias to the transistor Q3 can set the resistance value and the transistor size (= the magnitude of the passing current) regardless of the resistance value and characteristics of the time constant circuit 6. For this reason, it becomes easy to adjust the bias supply amount when the transistor Q3 is turned on and off, and the bias supply amount when the transistor Q3 is kept on.

なお、ダイオードとして機能するトランジスタＱ５については、抵抗Ｒ０単独の時よりも大きな電流を通過させることにより、トランジスタＱ１とトランジスタＱ２に大きな電流を流通させ、トランジスタＱ３のターンオンを促進するという役目を担う。このトランジスタＱ５のオン電圧を適切な値に設定しておく事により
、不測の事態によりコンデンサＣ０の端子間電圧が規定の値よりも低下した時、トランジスタＱ３をオンさせて迅速に規定の値に復帰させたり、逆に、ノイズでトランジスタＱ３が誤ってオンするのを防止したりすることができる。ただし、起動時（＝コンデンサＣ０の端子間電圧がゼロ）と通常動作時（＝コンデンサＣ０の端子間電圧が規定値）において、それぞれ抵抗Ｒ０を流れる電流の差が極めて大きく、トランジスタＱ３のターンオンを促進する必要が無いと判断される場合にはトランジスタＱ５は省略することもできる。 Note that the transistor Q5 functioning as a diode plays a role of facilitating the turn-on of the transistor Q3 by allowing a larger current to flow through the transistors Q1 and Q2 by passing a larger current than when the resistor R0 alone. By setting the ON voltage of the transistor Q5 to an appropriate value, when the voltage between the terminals of the capacitor C0 falls below a specified value due to an unexpected situation, the transistor Q3 is turned ON to quickly reach the specified value. In other words, the transistor Q3 can be prevented from being erroneously turned on due to noise. However, the difference between the currents flowing through the resistor R0 is very large during startup (= the voltage between terminals of the capacitor C0 is zero) and during normal operation (= the voltage between terminals of the capacitor C0 is a specified value). If it is determined that there is no need to promote the transistor Q5, the transistor Q5 can be omitted.

図１の回路が定常動作状態の時、電圧発生回路７ａ内部のトランジスタＱ１、Ｑ４、誤差増幅器ＡＭＰ、バンドギャップリファレンス回路ＢＧによる回路部分は、その回路構成からリップルフィルタと見なすこともできる。電圧発生回路７ａの入力端子ＩＮの電圧（ＶIN）が出力端子ＯＵＴの電圧（ＶOUT ）（＝図２のＶR1）よりも充分に高い場合、電圧発生回路７ａのリップルフィルタ機能により電圧（ＶIN）に含まれるノイズは大幅に低減され、電圧（ＶOUT ）はノイズの少ない直流電圧となる。当然、時定数回路６から取り出される電圧（＝図２のＶR2）はノイズの少ない直流電圧となる。 When the circuit of FIG. 1 is in a steady operation state, the circuit portion including the transistors Q1 and Q4, the error amplifier AMP, and the bandgap reference circuit BG inside the voltage generation circuit 7a can be regarded as a ripple filter because of its circuit configuration. When the voltage (V IN ) of the input terminal IN of the voltage generation circuit 7a is sufficiently higher than the voltage (V OUT ) (= V R1 of FIG. 2) of the output terminal OUT, the voltage ( The noise included in V IN ) is greatly reduced, and the voltage (V OUT ) is a DC voltage with less noise. Naturally, the voltage (= V R2 in FIG. 2) extracted from the time constant circuit 6 is a DC voltage with less noise.

一方、電圧（ＶIN）と電圧（ＶOUT ）が近似の場合、電圧（ＶIN）に含まれるノイズが電圧発生回路７ａを、ほぼそのまま通過してしまう。しかし、時定数回路６がローパスフィルタとして機能するため、結果的に時定数回路６から取り出される電圧（＝図２のＶR2）はノイズの少ない直流電圧となる。従って、本発明による電圧発生回路を従来の安定化回路に適用しても、安定化回路自体の回路動作を損なうことは無い。 On the other hand, when the voltage (V IN ) and the voltage (V OUT ) are approximate, noise included in the voltage (V IN ) passes through the voltage generation circuit 7a almost as it is. However, since the time constant circuit 6 functions as a low-pass filter, the voltage (= V R2 in FIG. 2) extracted from the time constant circuit 6 is a DC voltage with less noise. Therefore, even if the voltage generation circuit according to the present invention is applied to a conventional stabilization circuit, the circuit operation of the stabilization circuit itself is not impaired.

以上の本発明の説明において、図１のトランジスタＱ１、誤差増幅器ＡＭＰ、バンドギャップリファレンス回路ＢＧ、抵抗Ｒ１およびＲ２はシリーズレギュレータを構成している。しかし時定数回路６への供給電流を調整するトランジスタＱ１やそれに類する素子が存在するものであれば、例えば三端子レギュレータなどを構成するものであっても良い。また、本発明による電圧発生回路７ａは、図２のように電圧安定化回路の基準電圧供給用に限らず、時定数回路（ＲＣフィルタ）を介して安定度の高い電圧を供給する場面に広く適用することが可能である。   In the above description of the present invention, the transistor Q1, the error amplifier AMP, the band gap reference circuit BG, and the resistors R1 and R2 of FIG. 1 constitute a series regulator. However, as long as the transistor Q1 for adjusting the current supplied to the time constant circuit 6 or an element similar thereto exists, a three-terminal regulator or the like may be configured, for example. Further, the voltage generation circuit 7a according to the present invention is not limited to the supply of the reference voltage of the voltage stabilization circuit as shown in FIG. 2, but is widely used for supplying a highly stable voltage via a time constant circuit (RC filter). It is possible to apply.

本発明による電圧発生回路と時定数回路の回路図。FIG. 3 is a circuit diagram of a voltage generation circuit and a time constant circuit according to the present invention. 電子機器内部の一般的な配置を示すブロック図。The block diagram which shows the general arrangement | positioning inside an electronic device. 時定数回路から出力される電圧信号の波形図。The wave form diagram of the voltage signal output from a time constant circuit. 従来における一般的な電圧発生回路と時定数回路の充電促進技術を示す回路図。The circuit diagram which shows the charge promotion technique of the conventional common voltage generation circuit and time constant circuit.

符号の説明Explanation of symbols

１：電源
２：負荷装置
３：パワートランジスタ
６：時定数回路
７、７ａ：電圧発生回路
ＡＭＰ：誤差増幅器
ＢＧ：バンドギャップリファレンス回路
Ｃ０：時定数回路を構成するコンデンサ
ＩＮ：電圧発生回路の入力端子
ＯＵＴ：電圧発生回路の出力端子
Ｑ１：トランジスタ（第１のトランジスタ）
Ｑ２：トランジスタ（第２のトランジスタ）
Ｑ３：トランジスタ（第３のトランジスタ）
Ｑ５：トランジスタ（ダイオード）
Ｒ０：時定数回路を構成する抵抗
Ｒ３：抵抗（バイアス回路）
ＶD ：電源からの供給電圧
ＶR1：電圧発生回路の出力電圧
ＶR2：時定数回路の出力電圧
ＶS ：負荷装置への供給電圧 1: power supply 2: load device 3: power transistor 6: time constant circuit 7, 7a: voltage generation circuit AMP: error amplifier BG: band gap reference circuit C0: capacitor constituting time constant circuit IN: input terminal of voltage generation circuit OUT: output terminal Q1 of the voltage generation circuit: transistor (first transistor)
Q2: Transistor (second transistor)
Q3: Transistor (third transistor)
Q5: Transistor (diode)
R0: resistor constituting the time constant circuit R3: resistor (bias circuit)
V D : supply voltage V R1 : output voltage V R2 of voltage generation circuit: output voltage V S of time constant circuit: supply voltage to load device

Claims (5)

抵抗とコンデンサを含む時定数回路を介して該時定数回路の出力側に設けられた機能回路に所定の電圧を供給するための電圧供給回路において、
該時定数回路に電圧・電流を供給するように、入力端子と該時定数回路の間に設けられた第１のトランジスタと、
その制御端子が該第１のトランジスタの制御端子と共通接続され、その主電流路に該第１のトランジスタを通過する電流に応じた電流を流すように構成された第２のトランジスタと、
その主電流路が該時定数回路を構成する抵抗に並列接続された第３のトランジスタと、
該第２のトランジスタの主電流路を通過する電流の供給を受けて該第３のトランジスタの制御端子にバイアスを供給するバイアス回路と、
を具備することを特徴とする電圧供給回路。 In a voltage supply circuit for supplying a predetermined voltage to a functional circuit provided on the output side of the time constant circuit via a time constant circuit including a resistor and a capacitor,
A first transistor provided between the input terminal and the time constant circuit so as to supply voltage / current to the time constant circuit;
A second transistor whose control terminal is connected in common with the control terminal of the first transistor and configured to flow a current according to a current passing through the first transistor in the main current path;
A third transistor whose main current path is connected in parallel to a resistor constituting the time constant circuit;
A bias circuit for receiving a supply of current passing through a main current path of the second transistor and supplying a bias to a control terminal of the third transistor;
A voltage supply circuit comprising: 前記バイアス回路は、前記時定数回路を構成するコンデンサの端子間電圧が低い時に、前記第１のトランジスタの主電流路を通過する電流の大きさに応じて前記第３のトランジスタをオン状態とするようなバイアスを供給することを特徴とする、請求項１に記載した電圧供給回路。 The bias circuit turns on the third transistor according to the magnitude of the current passing through the main current path of the first transistor when the voltage between the terminals of the capacitor constituting the time constant circuit is low. The voltage supply circuit according to claim 1, wherein the bias is supplied. 前記バイアス回路が抵抗素子よりなることを特徴とする、請求項２に記載した電圧供給回路。 The voltage supply circuit according to claim 2, wherein the bias circuit includes a resistance element. 前記時定数回路の端子間電圧に相等する帰還電圧信号と電圧値が安定した基準電圧信号を受信し、当該２つの電圧信号の大きさに応じて前記第１のトランジスタを通過する電流を制御するための信号を生成する誤差増幅器を更に具備し、
前記第１のトランジスタが、該誤差増幅器と共に前記時定数回路の端子間電圧を一定にするためのレギュレータ回路を構成することを特徴とする、請求項１から請求項３のいずれかに記載した電圧供給回路。 A feedback voltage signal equivalent to the voltage between the terminals of the time constant circuit and a reference voltage signal with a stable voltage value are received, and the current passing through the first transistor is controlled according to the magnitude of the two voltage signals. An error amplifier for generating a signal for
The voltage according to any one of claims 1 to 3, wherein the first transistor constitutes a regulator circuit for making the voltage across the time constant circuit constant together with the error amplifier. Supply circuit. 前記時定数回路を構成する抵抗に対して並列接続されたダイオードを更に具備することを特徴とする、請求項１から請求項４のいずれかに記載された電圧供給回路。 5. The voltage supply circuit according to claim 1, further comprising a diode connected in parallel to a resistor constituting the time constant circuit. 6.
JP2005286667A 2005-09-30 2005-09-30 Voltage supply circuit Pending JP2007094970A (en)

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