201245921 六、發明說明： 【發明所屬之技術領域】 本發明係關於低壓降穩壓器’尤指利用感測負載電流的變化來 調整誤差放大器的輸出阻抗以補償極點位置改變的低壓降穩壓器與 相關的極點補償方法。 【先前技術】 傳統的低壓降穩壓器（low-dropoutreg\ilator)在輕負載（light load)的操作下，由於負載阻抗值的增加將導致由低壓降穩屢器之 輸出端所產生的極點（pole)往低頻方向移動。因此，由於低壓降 穩壓器之輸出端所產生的極點會朝由低壓降穩壓器的誤差放大器輸 出端所產生的主極點（dominantpole)移動，故而造成系統頻寬的 下降以及相位邊界（phasemargin)的減少’影響穩壓器的穩定度。 第1圖為習知低壓降穩壓器的增益與相位對於頻率的關係圖。第 1圖顯示當低壓降穩壓器於重負載與輕負載時，極點移動的情形。 在輕負載的情形下，極點P2會移動至左方較低頻的極點p2,（在此 為主極點），其中極點Pi的位置係由低壓降穩壓器中的誤差放大器 之輸出端來決定，而極點P2的位置係由低壓降穩壓器中的輸出端來 決定。當極點Ρ!與P2靠近時，將造成相位提早下降，使得相位邊 界在頻寬内就已消失殆盡，而導致系統的不穩定。 201245921 【發明内容】 本發明揭示一種低壓降穩壓器，包含誤差放大器、導通元件、回 授網路以及極闕償單元。該誤差放大翻綠大參考電壓與回授 電左之間的電m生誤差信號；該導通元件係#接於該誤差放 大益’用以依雜誤差信絲產生輸出電壓；該回授網關麵接於 该導通兀件，用以依據該輸出電壓來產生該回授電壓；以及極點補 償單7L 誤差放A器之輸出端，用以依據貞載電流的變化 來調整該誤差放大器的触阻抗以補倾健降麵^之極點位置 改變。 本發明另揭示低壓降穩壓器的極點補償方法，包含：感測該低 壓降穩壓ϋ之負載電流的變化；以及當該負載電流產生變化時，調 整该低壓降穩壓器之誤差放大器的—輸出阻抗，來補償該低壓降穩 壓器之極點位置改變。 【實施方式】 第2圖為本發明一實施例的示意圖。低壓降穩壓器200包含(但 不侷限於)誤差放大器220、導通元件23〇、回授網路24()以及極點 補償單元25〇 ’其中誤差放大器no係用來放大參考電壓L斑回 授電壓Vf之間的-電壓差以產生—誤差信號％;導通元件23〇輕 接於誤差放大H 220，用以依據誤差信號％來產生輸㈣壓v⑽； 回授網路24〇係麵接於導通元件23〇，用以依據輸出電壓v⑽來產 生回授電壓vf;以及極點補償單元25G係減於誤差放大器22〇之201245921 VI. Description of the Invention: [Technical Field] The present invention relates to a low dropout regulator, particularly a low dropout regulator that utilizes a change in sense load current to adjust the output impedance of an error amplifier to compensate for pole position changes. Related pole compensation methods. [Prior Art] A conventional low-dropout regulator (low-dropoutreg\ilator), under light load operation, will cause a pole generated by the output of the low-voltage drop stabilizer due to an increase in the load impedance value. (pole) moves in the low frequency direction. Therefore, since the pole generated at the output of the low-dropout regulator moves toward the dominant pole generated by the error amplifier output of the low-dropout regulator, the system bandwidth is reduced and the phase boundary is phasemargin. The reduction of 'affects the stability of the regulator. Figure 1 is a plot of gain vs. phase vs. frequency for a conventional low dropout regulator. Figure 1 shows the pole shift when the low dropout regulator is under heavy and light loads. In the case of light load, the pole P2 will move to the lower pole p2 of the left side (here the main pole), where the position of the pole Pi is determined by the output of the error amplifier in the low dropout regulator. The position of the pole P2 is determined by the output of the low dropout regulator. When the pole is near! When it is close to P2, it will cause the phase to drop early, so that the phase boundary disappears within the bandwidth and the system is unstable. 201245921 SUMMARY OF THE INVENTION The present invention discloses a low dropout regulator comprising an error amplifier, a conducting component, a feedback network, and a pole compensation unit. The error amplifies the electrical m error signal between the green reference voltage and the feedback left; the conduction component is connected to the error amplification to generate an output voltage according to the error error signal; the feedback gateway surface Connected to the conduction component for generating the feedback voltage according to the output voltage; and the output terminal of the pole compensation single 7L error amplifier for adjusting the contact impedance of the error amplifier according to the change of the load current The position of the pole of the make-up and descending surface ^ changes. The invention further discloses a pole compensation method for a low dropout regulator, comprising: sensing a change of a load current of the low dropout voltage regulator; and adjusting an error amplifier of the low dropout regulator when the load current changes - Output impedance to compensate for pole position changes of the low dropout regulator. Embodiments Fig. 2 is a schematic view showing an embodiment of the present invention. The low dropout regulator 200 includes, but is not limited to, an error amplifier 220, a pass element 23, a feedback network 24 (), and a pole compensation unit 25 〇 'where the error amplifier no is used to amplify the reference voltage L spot feedback The voltage difference between the voltages Vf is generated - the error signal %; the conduction element 23 is lightly connected to the error amplification H 220 for generating the input (four) voltage v (10) according to the error signal %; the feedback network 24 is connected to the system The conducting element 23A is configured to generate the feedback voltage vf according to the output voltage v(10); and the pole compensation unit 25G is subtracted from the error amplifier 22
S 5 201245921 一輸出端，用以依據負載電流Ibad的變化來動態地調整誤差放大器 220的一輸出阻抗，以補償低壓降穩壓器22〇之極點位置改變。此 外，在低壓降穩壓器200的輸出端接一負載網路260，其中 負載網路260係用以接收負載電流Ii〇ad。請注意，誤差放大器22〇、 導通元件zju以及回授網路240可代表習知低壓降穩壓器27〇的基 本架構，而第1圖可視為習知低壓降穩壓器27〇的增益與相位對頻 率所作之圖。此外，習知低壓降穩壓器27〇的基本架構僅供說明之 需，並非用來侷限本發明之複數個變化形，例如，本發明可在誤差 放大器220與導通元件230之間耦接一電壓緩衝器，或是增加其他 旁路電容II等。由於習知低壓降穩壓器27G運作原理為熟f技藝者 可輕易瞭解，故在此便不再贅述。 如第1圖所不，負載阻抗值的改變會造成極點（例如極點p2) 位置的移動’因此為m由於負载情職不同所造成的極點位置 改1以及系統穩定性的惡化，故極點補償單元250係依據負載電流 Ibad的變化來調整系統中另一個極點’以降低極點位置改變對於系 統的影響。在本實施例中，極點補償單元25〇係接收並依據一負載 電流Iload變化的信號來調整極點補償單元25〇的一輸出阻抗，以達 到調整/影響誤差放大器220的該輸出阻抗的目的。請注意，極點補 償單元250可由負載網路260直接感測負載電流Ii〇ad的變化、依據 流經導通元件230的電流Ip間接感測負載電流Ii〇ad的變化，或是透 過其他可行方式來感測負載電流I1〇ad的變化。另外，極點補償單元 250 了透過與誤差放大器220並聯、串聯或其他可行方式來實現誤 201245921 •差放Μ 之輸出阻抗的動態調整。關於運用極點補償單元250 以增加系統穩定性的說明，可參閱第3圖。 _第3圖為本發明—實_的增益與她對鮮_侧。如圖 所:、，當極點&朝極點Ρι移動以致於極點&糾接近時，若極點 ⑽被^至極點p2原來的位置，則兩極點軸的淨效應幾乎可抵 消也就疋》兒’對於系統來說，極點位置幾乎沒有改變，所以相位 邊界也/又有減v ’更廣泛地來說，當極點&朝極點p丨移動以致於 極點h與p2接料，若極點Ρι驗鶴域近難&縣的位置， 則兩極點移_淨效應可減小，因此，對於系統來說，極點位置僅 會具有輕微變動’所以她邊界僅會频受聰響。舉例來說，在 第2圖中’虽負載電流u生變化而造成—極點位置的改變（例 如極點P2朝極點Pl移動），極點補償單元25〇便依據負載電流‘變 化的信號來動態地調整誤差放大器22G的輸出阻抗以藉由移動另 一極點（例如將極點Pl移動至極點Μ來的位置或趨近極點匕原 來的位置）來消弭/減輕極點位置移動對系統穩定性的影響。 第4圖為另-實關的電路示意圖。低壓降穩壓器4〇〇包含誤 差放大器420、導通元件430、回授網路440以及極點補償單元45〇。 在本實施例中，誤差放大器420包含有放大器425、輸出電容Q以 及輸出電阻艮’且用來放大參考電壓Vref與回授電壓％之間的一電 壓差以產生一誤差信號Ve;導通元件430為p型金氧半場效功率電 晶體MP1 ’ MP1的閘極辆接於誤差放大器420，用以依據誤差信號 201245921 ve來產生輸出賴VQut，以及Cgs與〜分職表· _極源極 與閘極-錄之_寄生電容；回授網路包含複數個電阻幻盘 R2，構成-分壓電路而輕接於Μρι的没極，用以依據輸出電壓I 來產生回授電壓Vf;以及極點補償單元包含（但不舰於）電 流感測器454與阻抗調整器，其中電流感測器你_於_ 的源極用以感測負載電流Ii〇ad之變化來產生一控制信號&，而阻 抗調整器458祕於誤差放大器物之輸出端&，且具有一可變阻 抗zt’用以依據控制信號Sc來調整可變阻抗&。此外，在低壓降穩 壓器400的輸出端越輸出電容。。以下以輕負載為例來說 明本發明所揭示的極點補償程序。 請參考第3圖與第4圖。在重負载的操作環境之下，低壓降穩 壓器働於誤紐μ 的輸_ &所產生雜點&與在低壓 降穩壓器400的輸出端N〇ut所產生的極點^的相對位置如極叫 與p2所示’亦即極點Pcl的頻率低於極點Pc2。然而，當低壓降轉壓 器操作在輕㈣，繼流Ik>ad減少，使得極點^朝低頻方向 移動。極點pcl的頻率wPc丨可表示為 ^Pc\ ------------ (Re + Re{Z}). (Ce + + ApiCgd + Im{Z}) 其中Z係為由誤差放大器420的輪出軌所看到極點補償單元· 的輸出阻抗、則2}與/响分別代表極點補償單元的輸出阻 抗Z的實部與虛部，以及Αρι為Μρι的電壓增益（她哪㈣。所 以，此時電流感測器454制到負栽電流Ii〇ad減少，控制信號^會 201245921S 5 201245921 An output terminal for dynamically adjusting an output impedance of the error amplifier 220 according to a change of the load current Ibad to compensate for a pole position change of the low dropout regulator 22 . In addition, a load network 260 is coupled to the output of the low dropout regulator 200, wherein the load network 260 is configured to receive the load current Ii〇ad. Please note that the error amplifier 22〇, the conduction element zju, and the feedback network 240 can represent the basic architecture of the conventional low-dropout regulator 27〇, and FIG. 1 can be regarded as the gain of the conventional low-dropout regulator 27〇. A plot of phase versus frequency. In addition, the basic architecture of the conventional low-dropout regulator 27A is for illustrative purposes only, and is not intended to limit the plurality of variations of the present invention. For example, the present invention can couple between the error amplifier 220 and the conductive element 230. Voltage buffer, or add other bypass capacitors II and so on. Since the operating principle of the conventional low-dropout regulator 27G can be easily understood by a skilled person, it will not be described here. As shown in Figure 1, the change in the load impedance value will cause the pole (such as the pole p2) to move. Therefore, the pole position is changed due to the load responsibilities, and the stability of the system is deteriorated. Therefore, the pole compensation unit The 250 Series adjusts the other pole in the system based on the change in load current Ibad to reduce the impact of pole position changes on the system. In the present embodiment, the pole compensation unit 25 receives and adjusts an output impedance of the pole compensation unit 25A according to a signal of a load current Iload to achieve the purpose of adjusting/affecting the output impedance of the error amplifier 220. Please note that the pole compensation unit 250 can directly sense the change of the load current Ii〇ad by the load network 260, indirectly sense the change of the load current Ii〇ad according to the current Ip flowing through the conduction element 230, or through other feasible means. The change in load current I1〇ad is sensed. In addition, the pole compensation unit 250 realizes the dynamic adjustment of the output impedance of the error 201245921 • differential amplifier by parallel connection, series connection or other feasible manner with the error amplifier 220. For a description of the use of pole compensation unit 250 to increase system stability, see Figure 3. _ Figure 3 is the gain of the invention - the real _ side. As shown in the figure: , when the pole & move toward the pole Ρι so that the pole & close, if the pole (10) is ^ to the original position of the pole p2, the net effect of the pole pole is almost canceled. 'For the system, the pole position is almost unchanged, so the phase boundary is also reduced by v. More broadly, when the pole & moves toward the pole p丨 so that the poles h and p2 are picked up, if the pole is Ρι If the position of the crane field is near and difficult, then the two-pole point shift _ net effect can be reduced, so for the system, the pole position will only have a slight change' so her border will only be very fluent. For example, in Fig. 2, 'the load current u changes, the pole position changes (for example, the pole P2 moves toward the pole P1), the pole compensation unit 25 dynamically adjusts according to the load current' change signal. The output impedance of the error amplifier 22G is used to cancel/mitigate the effect of pole position shift on system stability by moving another pole (e.g., moving the pole P1 to a pole 或 position or approaching a pole 匕 original position). Figure 4 is a schematic diagram of another-real circuit. The low dropout regulator 4A includes an error amplifier 420, a pass element 430, a feedback network 440, and a pole compensation unit 45A. In the present embodiment, the error amplifier 420 includes an amplifier 425, an output capacitor Q, and an output resistor 艮' and is used to amplify a voltage difference between the reference voltage Vref and the feedback voltage % to generate an error signal Ve; the conduction element 430 The gate of the p-type MOS field-effect power transistor MP1 'MP1 is connected to the error amplifier 420 for generating the output VQut according to the error signal 201245921 ve, and the Cgs and the _ pole source and gate Polar-recorded _ parasitic capacitance; the feedback network includes a plurality of resistor floppy disks R2, which constitute a voltage dividing circuit and are lightly connected to the 没ρι 没, for generating the feedback voltage Vf according to the output voltage I; The compensation unit includes (but does not ship with) the current sensor 454 and the impedance adjuster, wherein the source of the current sensor is used to sense the change of the load current Ii〇ad to generate a control signal & The impedance adjuster 458 is secreted at the output of the error amplifier & and has a variable impedance zt' for adjusting the variable impedance & in accordance with the control signal Sc. In addition, the output capacitance is output at the output of the low dropout regulator 400. . The pole compensation procedure disclosed by the present invention will be exemplified below by taking a light load as an example. Please refer to Figures 3 and 4. Under heavy-duty operating conditions, the low-dropout regulator 働 误 的 的 的 所 所 所 所 所 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与 与The relative position is as shown in p2 and the frequency of the pole Pcl is lower than the pole Pc2. However, when the low-pressure drop converter operates at light (four), the relay Ik>ad is reduced, causing the pole to move toward the low frequency direction. The frequency wPc丨 of the pole pcl can be expressed as ^Pc\ ------------ (Re + Re{Z}). (Ce + + ApiCgd + Im{Z}) where the Z system is the error The output impedance of the pole compensation unit of the amplifier 420 is shown as the output impedance of the pole compensation unit, and the 2} and / ring respectively represent the real and imaginary parts of the output impedance Z of the pole compensation unit, and the voltage gain of Αρι is Μρι (here (four). Therefore, at this time, the current sensor 454 reduces the load current Ii〇ad, and the control signal ^ 201245921
控制阻抗調整器458 (例如調整可變M … 金J雙阻抗Zt，使輸出阻抗Z的實部 办{Z}降低）以減少誤差放大器·的輪出阻抗。 由於流經導通元件43〇的電流ΙρΆ，其中If係為流經回 綱路的電流，當負载情形由重負裁轉換至輕負载時，一般來 況僅會影響負載電流Ibad，所以Ip的變化主要是來自於U的變化， 因此電流感測請便透過流經導通树的電以來間接感測 U的變化。如前文所述，電流感測器454並不侷限於雛•以 間接感測I-的變化’亦接於負載網路以直接感測U的變化， 或疋透過其他可行方式來感》則11(^的變化。同樣地，阻抗調整器祝 亦可透過與誤差放大器420並聯、串聯或其他可行方式來調整誤差 放大器420的輸出阻抗。 此外，依據本實施例的另一變形，當電流感測器454所感測之負 載電流Iload減少以致低壓降穩壓器400之極點Ρ。2由一原本位置朝低 頻方向移鱗，㈣錢S。會控制阻抗調整g 458以致使原位於極 點PC2左側之極點pel朝右側高頻方向移動至改變位置後之極點 的右側，達到兩極點互換的效果以維持系統穩定性。另值得注意的 是，極點補償不僅止於重負載轉換到輕負載的情形，當發生輕負载 轉換至重負載的情形時，極點補償單元450亦可控制阻抗調整器458 的輸出阻抗Zt以維持系統穩定性。換言之，極點pci的移動係為雙 向式的。 201245921 第5圖為另一實施例的電路示意圖。低壓降穩壓器5〇〇主要是 基於第4圖低壓降穩壓器4〇〇的基本架構，因此，低壓降穩壓器5〇〇 包3誤差放大器520、導通元件530、回授網路540以及極點補償單 元55〇。在本實施例中’低壓降穩壓器500另包含電壓緩衝器（voltage buffer) 580與585，皆用以提供電壓緩衝之用。此外，在低塵降穩 墨器500的輸出端N〇ut耗接輸出電容Qut與負載電阻。極點補 侦單元550包含（但不侷限於）電流感測器μα與阻抗調整器Mg， 其中電流感測器554係耦接於導通元件53〇，用以感測負載電流 之變化來產生-㈣電壓Ve;以及阻抗調整器558係為湘n型金 氧半場效電晶H Mi來實賴-觀壓㈣電阻（她ag_ntr〇lled resistor)。Mi的閘極接收電流感測器554產生的控制電壓、，用以 依據控制輕Ve來織Ml的導軸度，躺實卿整電阻的效 果。此外，的汲極耦接於誤差放大器52〇之輸出端Ne，以及可 變電阻Rt耦接於的源極以表示阻抗調整器558的輸出電阻。由 於低壓降穩壓ϋ 5GG的運作功能係與第4圖巾低壓降穩壓器4〇〇的 功能相似’故其運作細節在此便不再贅述。 注意的是，電流感測器554所產生的控制信號雖然以電壓型式 呈現’但此僅供說明之用，並非用來侷限本發明之變形。也就是說， 電流感測器554並不一定是將電流信號轉換為電壓信號，阻抗調節 器558所接收的控制信號也不一定是電壓型式。 第6圖為本發明應用於一低壓降穩壓器的極點補償方法的一實 201245921 施例的流程圖。上述之極點補償方法可應用於低壓降穩壓器200、 4〇〇與5〇〇,並可簡單歸納如下： 步驟600 :開始； 步驟602 :感測-低壓降穩壓器之—負載電流的變化； 步驟604 :當該負載電流產生變化時，調整該低壓降穩壓器之一誤 差放大器的一輸出阻抗，來補償該低壓降穩壓器之極點 位置改變。 另外’針對步驟602，可依據所感測之負載電流變化來產生一 控制域；錢針對步驟6G4，可將具有―可變阻抗之—阻抗調整 器搞接於該誤差放大器之—輸㈣，以及依__信號來調整該 可變阻抗。舉例來說，當所感測之該貞載電流減少時，該控制信號 會控制該阻抗調魏來減少該縣放大器之該輸出阻抗，以補償極 點位置的移動H個情形下，當所感測之該負载電流減少以致 =低壓降麵$之—第二極點由—縣位置朝左側低頻方向移動 時丄該控制錢會控繼阻抗雕㈣致錄·二極點左側 之一第-極_右側高頻方向移動至改變位置後之該第二極點的右 =言之，應用於低壓降穩壓器的極點補償方法得以實現兩個極 轉祕敎性。由於熟1技藝者可根據上述健降 祕裔200、400與500的說明而輕易地瞭解第 作，於此便不另贅述。 母步驟的運 201245921 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍 所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第i圖為習知低壓降穩壓器之增益與相位對頻率的關係圖。 第2圖為本發明低壓降穩壓器之一實施例的示意圖。 第3圖為本發明另一實施例的增益與相位對頻率的關係圖。 第4圖為本發明另一實施例的示意圖。 第5圖為本發明另一實施例的不意圖。 第6圖為本發明應用於低壓降穩壓器之極點補償方法的一流程圖。 【主要元件符號說明】 200、270、400、500 低壓降穩壓器 220'420'520 誤差放大器 230、430、530 導通元件 240、440、540 回授網路 250、450、550 極點補償單元 260 負載網路 425 放大器 454 > 554 電流感測器 458 ' 558 阻抗調整器 580'585 電壓緩衝器 12The impedance adjuster 458 is controlled (e.g., the variable M ... gold J double impedance Zt is adjusted, and the real part of the output impedance Z is reduced {Z}) to reduce the wheel-out impedance of the error amplifier. Since the current flowing through the conduction element 43〇Ι, where If is the current flowing through the return path, when the load condition is switched from a heavy negative to a light load, the general condition only affects the load current Ibad, so the change of Ip is mainly It is a change from U, so current sensing should indirectly sense the change of U through the electricity flowing through the conduction tree. As mentioned above, the current sensor 454 is not limited to the younger ones. • Indirect sensing of the change in I- is also connected to the load network to directly sense the change of U, or to sense through other feasible means. (Changes in ^. Similarly, the impedance adjuster may also adjust the output impedance of the error amplifier 420 by being connected in parallel, in series, or other feasible manner with the error amplifier 420. Further, according to another variation of the embodiment, when current sensing The load current Iload sensed by the device 454 is reduced so that the pole of the low-dropout regulator 400 is Ρ2. The scale is shifted from the original position toward the low frequency direction, and (4) the money S. The impedance adjustment g 458 is controlled so that the pole is located on the left side of the pole PC2. The pel moves to the right side of the high frequency direction to the right side of the pole after changing position, achieving the effect of two poles interchange to maintain system stability. It is also worth noting that the pole compensation is not limited to the case of heavy load switching to light load when it occurs. When the light load is switched to a heavy load, the pole compensation unit 450 can also control the output impedance Zt of the impedance adjuster 458 to maintain system stability. In other words, the shift of the pole pci 201245921 Figure 5 is a circuit diagram of another embodiment. The low-dropout regulator 5〇〇 is mainly based on the basic structure of the low-dropout regulator 4〇〇 of Figure 4, therefore, the low-voltage drop-down The voltage regulator 5 includes an error amplifier 520, a conducting component 530, a feedback network 540, and a pole compensation unit 55. In the present embodiment, the low dropout regulator 500 further includes a voltage buffer 580 and 585, both for providing voltage buffering. In addition, the output terminal Qut and the load resistance are consumed at the output terminal of the low dust drop stabilizer 500. The pole compensation unit 550 includes (but is not limited to) a sense of current The detector μα is coupled to the impedance adjuster Mg, wherein the current sensor 554 is coupled to the conductive element 53A for sensing a change of the load current to generate a voltage voltage Ve; and the impedance adjuster 558 is a gold n-type gold The oxygen half-field effect crystal H Mi is based on the (four) resistance (her ag_ntr〇lled resistor). The gate of Mi receives the control voltage generated by the current sensor 554, and is used to guide the M1 according to the control light Ve. Axis, the effect of lying on the whole resistance. In addition, the 汲The pole is coupled to the output terminal Ne of the error amplifier 52〇, and the source to which the variable resistor Rt is coupled to represent the output resistance of the impedance adjuster 558. The operating function of the low voltage drop regulator ϋ 5GG and the fourth towel The function of the low-dropout regulator 4〇〇 is similar, so the details of its operation will not be described here. Note that the control signal generated by the current sensor 554 is presented in voltage mode, but this is for illustrative purposes only. It is not intended to limit the variations of the present invention. That is, the current sensor 554 does not necessarily convert the current signal into a voltage signal, and the control signal received by the impedance adjuster 558 is not necessarily a voltage type. Figure 6 is a flow chart of a real-time 201245921 embodiment of the pole compensation method applied to a low-dropout regulator of the present invention. The above-mentioned pole compensation method can be applied to the low-dropout regulators 200, 4〇〇 and 5〇〇, and can be simply summarized as follows: Step 600: Start; Step 602: Sensing-Low-Dropout Regulator-Load Current Step 604: When the load current changes, an output impedance of the error amplifier of one of the low dropout regulators is adjusted to compensate for the pole position change of the low dropout regulator. In addition, for step 602, a control domain may be generated according to the sensed load current change; for step 6G4, a variable impedance-impedance adjuster may be connected to the error amplifier (four), and The __ signal adjusts the variable impedance. For example, when the sensed load current is reduced, the control signal controls the impedance modulation to reduce the output impedance of the county amplifier to compensate for the movement of the pole position. In the case of sensing H, The load current is reduced so that the low voltage drop surface is - the second pole is moved from the county position to the left side in the low frequency direction. The control money is controlled by the impedance carving (4) Recording · One of the left side of the two poles Right to the second pole after moving to the changed position = the pole compensation method applied to the low-dropout regulator achieves two extreme turn-offs. Since the skilled person can easily understand the work according to the descriptions of the above-mentioned Jianshen Miku 200, 400 and 500, no further details will be described herein. The above description of the parent process is only a preferred embodiment of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention. [Simple diagram of the diagram] The i-th diagram is the relationship between the gain and phase versus frequency of a conventional low-dropout regulator. Figure 2 is a schematic diagram of one embodiment of a low dropout regulator of the present invention. Figure 3 is a graph showing gain versus phase vs. frequency for another embodiment of the present invention. Figure 4 is a schematic view of another embodiment of the present invention. Figure 5 is a schematic view of another embodiment of the present invention. Figure 6 is a flow chart of the pole compensation method applied to the low dropout regulator of the present invention. [Main component symbol description] 200, 270, 400, 500 low dropout voltage regulator 220'420'520 error amplifier 230, 430, 530 conduction element 240, 440, 540 feedback network 250, 450, 550 pole compensation unit 260 Load Network 425 Amplifier 454 > 554 Current Sense 458 ' 558 Impedance Adjuster 580'585 Voltage Buffer 12