JP2007097395A - Low-consumption current circuit, voltage regulator equipped with the low-consumption current circuit, and dc-dc converter - Google Patents
Low-consumption current circuit, voltage regulator equipped with the low-consumption current circuit, and dc-dc converter Download PDFInfo
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Abstract
Description
本発明は保護回路を備えた回路の低消費電流技術に係り、特にボルテージレギュレータ、ＤＣ−ＤＣコンバータなどの電源用回路の低消費電流化に有効である。 The present invention relates to a low current consumption technology of a circuit provided with a protection circuit, and is particularly effective in reducing the current consumption of power supply circuits such as a voltage regulator and a DC-DC converter.
近年、携帯用の各種電子機器が普及しているが、今後ますます要求が高まっていく省エネルギー化や環境への配慮からICの低消費電流化は避けられない課題である。しかしながら技術の発展とともに電源ICには高機能化、高精度化が求められており、これによる回路規模の拡大が消費電流の増大を招いている。回路規模が大きくなっても回路全体の消費電流を抑えることが課題である。 In recent years, various portable electronic devices have become widespread. However, due to energy saving and environmental considerations, which are increasingly demanded in the future, low current consumption of ICs is an unavoidable issue. However, with the development of technology, power supply ICs are required to have higher functionality and higher accuracy, and the increase in circuit scale caused by this increase in current consumption. Even if the circuit scale becomes large, it is a problem to suppress the current consumption of the entire circuit.
図４は、保護回路（過電流保護回路）Ｈを備えた従来のボルテージレギュレータの基本ブロック図である。
同図において、出力ドライバトランジスタＭ２から出力される出力電圧Ｖｏｕｔを抵抗Ｒ１とＲ２で分割し、それを差動増幅器DAの一方の入力（−）に帰還し、差動増増幅器ＤＡの他方の入力（＋）には電流源ＩＳ、電圧源Ｖで生成される基準となる電圧を入力し、この差動増幅器ＤＡの出力を出力ドライバトランジスタＭ２のゲートに印加し、この出力ドライバトランジスタＭ２のオンオフを制御することによってボルテージレギュレータの出力の定電圧化を図っている。
FIG. 4 is a basic block diagram of a conventional voltage regulator provided with a protection circuit (overcurrent protection circuit) H.
In the figure, the output voltage Vout output from the output driver transistor M2 is divided by resistors R1 and R2, and fed back to one input (−) of the differential amplifier DA, and the other input of the differential amplifier DA. (+) Inputs a reference voltage generated by the current source IS and the voltage source V, applies the output of the differential amplifier DA to the gate of the output driver transistor M2, and turns on / off the output driver transistor M2. By controlling, the output of the voltage regulator is made constant.
このボルテージレギュレータにおいては保護回路Ｈは常時動作しており、保護回路Ｈの消費電流I1も常時流れている。しかし、一般的には数百mA以上で過電流保護を行うので、低出力電流(数十mA)で通常動作している状況においては出力電流のマージンもあり保護回路Ｈは役に立っていない。保護回路Ｈは万一のための回路であり、危険な状態から十分マージンがある場合においては必ずしも動作している必要はない。 In this voltage regulator, the protection circuit H always operates, and the consumption current I1 of the protection circuit H always flows. However, since the overcurrent protection is generally performed at several hundred mA or more, the protection circuit H is not useful in a situation where the normal operation is performed at a low output current (several tens of mA) because there is a margin of the output current. The protection circuit H is a circuit for safety, and does not necessarily have to operate when there is a sufficient margin from a dangerous state.
また、ICの発熱量は｛(入力電圧-出力電圧)×出力電流｝で求められる。これからわかるようにICが低出力電流動作をしている場合、ICの発熱量は小さく過熱保護回路が必要ない。このように低出力電流動作時に不要な保護回路も多い。ICの多機能化により保護回路規模が大きくなってくるとそこで消費される電流を無視することはできない。なお、電源部の異常検出に関しては、例えば特開２００２−０９５１６１号公報を参照されたい。 Further, the heat generation amount of the IC is obtained by {(input voltage-output voltage) × output current}. As can be seen, when the IC is operating at a low output current, the amount of heat generated by the IC is small and an overheat protection circuit is not required. As described above, there are many protection circuits that are not required when operating at a low output current. If the scale of the protection circuit increases due to the multi-functionalization of ICs, the current consumed there cannot be ignored. Regarding detection of abnormality in the power supply unit, refer to, for example, Japanese Patent Laid-Open No. 2002-095161.
上述したように、従来のボルテージレギュレータにおいては、低出力電流(数十mA)で通常動作している状況においては保護回路Ｈは役に立っていないにもかかわらず、保護回路Ｈは常時動作しており、消費電流I1も常時流れていて無駄な消費電流が費やされているという問題がある。 As described above, in the conventional voltage regulator, the protection circuit H is always operating even though the protection circuit H is not useful in a situation where the operation is normally performed at a low output current (several tens of mA). The current consumption I1 always flows, and there is a problem that wasteful current consumption is consumed.
本発明は、保護回路を動作させる必要がないときは保護回路を動作させないようにして消費電流の削減を図った低消費電流回路（請求項１〜３）および低消費電流化が可能なボルテージレギュレータ（請求項４）、ＤＣ−ＤＣコンバータ（請求項５）を提供することを目的としている。特に、請求項２では保護回路を動作させる閾値となる出力電流をウエハプロセスの後工程で設定できるようにし歩留り向上を図ることを目的としている。 The present invention provides a low current consumption circuit that reduces the current consumption by not operating the protection circuit when it is not necessary to operate the protection circuit, and a voltage regulator capable of reducing the current consumption. It is an object of the present invention to provide a DC-DC converter (Claim 5). In particular, an object of the present invention is to improve the yield by setting an output current as a threshold value for operating the protection circuit in a subsequent process of the wafer process.
本発明は上記目的を達成するために。電源ICの出力電流値をモニタし、ある出力電流値を超えた場合つまり必要な場合だけ保護回路を動作させ、それ以外の場合には不要な保護回路の動作を停止させるようにし、通常動作における低消費電流化を達成するようにしたものである。 The present invention achieves the above object. The output current value of the power supply IC is monitored, and when a certain output current value is exceeded, that is, when necessary, the protection circuit is operated, and in other cases, the operation of the unnecessary protection circuit is stopped. It is intended to achieve low current consumption.
具体的には、
請求項１記載の発明は、保護回路と該保護回路の動作を停止させるためのスイッチを有する低消費電流回路であって、該低消費電流回路の出力電流を検出する出力電流モニタ回路を備え、該モニタ回路により前記出力電流が所定の値より小さいときに前記スイッチを制御して前記保護回路の動作を停止させることを特徴としている。
In particular,
The invention according to claim 1 is a low current consumption circuit having a protection circuit and a switch for stopping the operation of the protection circuit, comprising an output current monitor circuit for detecting an output current of the low current consumption circuit, When the output current is smaller than a predetermined value by the monitor circuit, the switch is controlled to stop the operation of the protection circuit.
請求項２記載の発明は、前記所定の値を、複数の抵抗または複数のトランジスタを用意し、それらを選択的にレーザトリミングすることによって設定したことを特徴としている。
請求項３記載の発明は、前記モニタ回路を、低消費電流回路に内蔵または外付けしたことを特徴としている。
The invention according to claim 2 is characterized in that the predetermined value is set by preparing a plurality of resistors or a plurality of transistors and selectively laser trimming them.
According to a third aspect of the present invention, the monitor circuit is built in or externally attached to a low current consumption circuit.
請求項４記載の発明は、上記低消費電流回路を備えたことを特徴とするボルテージレギュレータであり、請求項５記載の発明は、上記低消費電流回路を備えたことを特徴とするＤＣ−ＤＣコンバータである。 A fourth aspect of the present invention is a voltage regulator including the low current consumption circuit, and a fifth aspect of the invention is a DC-DC including the low current consumption circuit. It is a converter.
以下、本発明の効果を請求項ごとに述べる。
請求項1によれば、低出力電流動作している場合に不要な保護回路の動作を停止させることによって低消費電流化が可能になる。
The effects of the present invention will be described below for each claim.
According to claim 1, it is possible to reduce the current consumption by stopping the operation of the unnecessary protection circuit when the low output current operation is performed.
請求項2によれば、後工程でしきい値となる出力電流を設定することを可能にしているので、IC間のばらつき低減、歩留りの向上が期待できる。
請求項３によれば、出力電流モニタ回路をIC内蔵または外付けとすることで、回路規模の問題から内蔵が困難な場合には外付けにし、高精度にモニタしたい場合は外付けにするというように柔軟に対応できるようになる。
According to the second aspect, since it is possible to set an output current which becomes a threshold value in a subsequent process, it is possible to expect a reduction in variation between ICs and an improvement in yield.
According to the third aspect of the present invention, the output current monitoring circuit is built in or externally attached to the IC, so that it is externally attached when it is difficult to incorporate the output current monitoring circuit due to the problem of the circuit scale, and is externally attached when high accuracy monitoring is desired. To be able to respond flexibly.
（実施例）
本発明は、通常の低出力電流動作時に不要な保護回路の動作を停止し、回路全体の消費電流を抑えるものである。
(Example)
The present invention stops the operation of the protection circuit which is unnecessary during normal low output current operation, and suppresses the current consumption of the entire circuit.
（実施例の説明）
以下、本発明の実施例を、図面を用いて説明する。
図１は、本発明の第１の実施例に係るボルテージレギュレータを説明するための図である。
(Description of Examples)
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram for explaining a voltage regulator according to a first embodiment of the present invention.
本実施例のボルテージレギュレータは、ボルテージレギュレータのIC内部に図４の従来の回路素子に加えて、出力電流モニタ回路ＩＭ１とスイッチ１（ＳＷ１）をさらに内蔵している。出力電流モニタ回路ＩＭ１により出力電流をモニタし、その値によってスイッチ1（ＳＷ１）をコントロールして不要な場合はスイッチ１（ＳＷ１）を断にして保護回路１（Ｈ）を動作させないようにしたものである。 The voltage regulator of this embodiment further includes an output current monitor circuit IM1 and a switch 1 (SW1) in addition to the conventional circuit element of FIG. 4 in the IC of the voltage regulator. The output current is monitored by the output current monitor circuit IM1, and the switch 1 (SW1) is controlled according to the value, and the switch 1 (SW1) is turned off to prevent the protection circuit 1 (H) from operating when unnecessary. It is.
図２は、図１の出力電流モニタ回路ＩＭ１のさらに詳しい構成を示した図である。図２に示すように、図１の出力電流モニタＩＭ１を出力ドライバトランジスタＭ2のカレントミラートランジスタＭ1と電流モニタＩＭ２によって構成し、ある出力電流のしきい値を超えるまでスイッチ１（ＷＳ１）をオフしている。これによって保護回路１（Ｈ）は動作しないが、先に示したような理由により全く問題ない。 FIG. 2 is a diagram showing a more detailed configuration of the output current monitor circuit IM1 of FIG. As shown in FIG. 2, the output current monitor IM1 of FIG. 1 is constituted by the current mirror transistor M1 of the output driver transistor M2 and the current monitor IM2, and the switch 1 (WS1) is turned off until a certain output current threshold is exceeded. ing. As a result, the protection circuit 1 (H) does not operate, but there is no problem at all for the reason described above.
このとき保護回路Ｈの消費電流I1はゼロになる。所定の出力電流のしきい値を超えた場合はICの過熱等の危険があるので、それを電流モニタＩＭ２で検出してスイッチ１（ＷＳ１）をオンにして保護回路Ｈを動作させる。これにより保護回路Ｈは必要なときのみに動作させることが可能である。 At this time, the consumption current I1 of the protection circuit H becomes zero. If the threshold value of the predetermined output current is exceeded, there is a risk of overheating of the IC, etc., which is detected by the current monitor IM2, and the protection circuit H is operated by turning on the switch 1 (WS1). As a result, the protection circuit H can be operated only when necessary.
図２は、出力ドライバトランジスタＭ2とそのカレントミラートランジスタＭ1をMOSトランジスタで構成しているが、MOSトランジスタ以外のトランジスタで構成した場合も同様である。また、出力電圧のしきい値は抵抗またはトランジスタをあらかじめ複数個を設けておき、選択的にレーザトリミングすることによって任意の値に設定可能にすることで精度が向上するだけではなく、歩留りの向上を図ることができる。 In FIG. 2, the output driver transistor M2 and its current mirror transistor M1 are composed of MOS transistors, but the same applies when they are composed of transistors other than MOS transistors. In addition, the threshold of the output voltage can be set to an arbitrary value by providing a plurality of resistors or transistors in advance and selectively performing laser trimming, which not only improves accuracy but also improves yield. Can be achieved.
図３は、図１の出力電流モニタ回路ＩＭ１のさらに別の構成を示した図である。図３の例では、図１の出力電流モニタＩＭ１をボルテージレギュレータICの外部に出力電流モニタＩＭ３を設け、該出力電流モニタＩＭ３からの信号を端子Aに入力した例である。 FIG. 3 is a diagram showing still another configuration of the output current monitor circuit IM1 of FIG. The example of FIG. 3 is an example in which the output current monitor IM1 of FIG. 1 is provided outside the voltage regulator IC, and the signal from the output current monitor IM3 is input to the terminal A.
高精度の出力電流モニタをIC内蔵とすることは回路規模の問題から困難な場合がある。このような場合には図３のように出力電流モニタＩＭ３を外付けとするのが便利である。これによってある出力電流のしきい値を超えるまでスイッチ１（ＷＳ１）をオフされ、保護回路１（Ｈ）も動作しないが、先に示したような理由により全く問題はない。 It may be difficult to incorporate a high-accuracy output current monitor into the IC due to the problem of circuit scale. In such a case, it is convenient to attach the output current monitor IM3 as shown in FIG. As a result, the switch 1 (WS1) is turned off until a certain output current threshold value is exceeded, and the protection circuit 1 (H) does not operate. However, there is no problem at all for the reason described above.
Ｈ：保護回路（過電流保護回路）、
Ｍ１：カレントミラートランジスタ、
Ｍ２：出力ドライバトランジスタ、
Ｒ１，Ｒ２：抵抗、
Ｖｏｕｔ：出力電圧、
ＤＡ：差動増幅器、
Ｖ：電圧源、
ＩＭ１，ＩＭ２：出力電流モニタ、
ＳＷ１，ＳＷ２：スイッチ。
H: Protection circuit (overcurrent protection circuit),
M1: current mirror transistor,
M2: output driver transistor,
R1, R2: resistance,
Vout: output voltage,
DA: differential amplifier,
V: voltage source,
IM1, IM2: output current monitor,
SW1, SW2: switches.
Claims (5)
ボルテージレギュレータ。 A voltage regulator comprising the low current consumption circuit according to claim 1.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2006318335A JP2007097395A (en) | 2006-11-27 | 2006-11-27 | Low-consumption current circuit, voltage regulator equipped with the low-consumption current circuit, and dc-dc converter |
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| Application Number | Priority Date | Filing Date | Title |
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| JP2006318335A JP2007097395A (en) | 2006-11-27 | 2006-11-27 | Low-consumption current circuit, voltage regulator equipped with the low-consumption current circuit, and dc-dc converter |
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| Application Number | Title | Priority Date | Filing Date |
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| JP2002084421A Division JP2003284241A (en) | 2002-03-25 | 2002-03-25 | Low-consumption current circuit and voltage regulator equipped therewith, and dc-dc converter |
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| JP2007097395A true JP2007097395A (en) | 2007-04-12 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009296723A (en) * | 2008-06-03 | 2009-12-17 | Brother Ind Ltd | Power unit and image forming apparatus |
| JP2010146458A (en) * | 2008-12-22 | 2010-07-01 | Ricoh Co Ltd | Constant-voltage circuit |
| JP2013186735A (en) * | 2012-03-08 | 2013-09-19 | Seiko Instruments Inc | Voltage regulator |
| US9306457B2 (en) | 2013-12-04 | 2016-04-05 | Apple Inc. | Instantaneous load current monitoring |
-
2006
- 2006-11-27 JP JP2006318335A patent/JP2007097395A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009296723A (en) * | 2008-06-03 | 2009-12-17 | Brother Ind Ltd | Power unit and image forming apparatus |
| JP2010146458A (en) * | 2008-12-22 | 2010-07-01 | Ricoh Co Ltd | Constant-voltage circuit |
| JP2013186735A (en) * | 2012-03-08 | 2013-09-19 | Seiko Instruments Inc | Voltage regulator |
| US9306457B2 (en) | 2013-12-04 | 2016-04-05 | Apple Inc. | Instantaneous load current monitoring |
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