五 Α7 Β7 395084 經濟^中央標隼局貝工消费合i社印装 發明説明（1 ) 本發明係有關於一種射頻功率放大器’特別係有關 於一種高效率、大增益範圍控制之射頻功率放>大器及其 控制方法。 一般-而言，在無線通訊系統中均嚅要使用到射頻功 率放大器以便將信號放大傳送，而射頻功率放大器之設 計均要求高輸出功率以及高效率，又為使其能適用於各 種不同場所使用之通信距離，更要求其能提供輸出功率 之大範圍增益控制（wide range gain control) ’以避免不必 要之功率消耗β 目前使用於單晶微波積體電路(Monolithic Microwave Integrated Circuit ； MMIC)之射頻功率放大器之輸出功 率控制方法有下列幾項：（1)功率合成方式，（2)功率衰減 方式，（3 )UBIC 方式（Unbalanced Mas C_ascode)，（4)淡極 電壓控制方式，以及（5)閘極電壓控制方式。上述各種方 式各有其優缺點’茲分述如下。 一1 (1) 功率合成方式’其主要係利用多個功率合成器（或 是功率放大器）之工作組合以達到輸出功率控制之目 的。然而，由於受限於功率合成器之數目與成本之考量， 所以功率合成器之數目有其限制故而此方式之輸出功率 大小只能有幾種選擇，且控制電路相當複雜β (2) 功率衰減方式，其係在射頻電路中增加功率衰減 器，直接將所要輸出之功率加以衣減’以達到輸出功率 控制之目的。然而，在實際應用上想要在MMIC中設計 一個具有大範圍功率哀減能力’低損耗且低成本的衰減 (請先閲讀背面之注意事項再填寫本頁) -裝- τ訂Five Α7 Β7 395084 Economy ^ Central Standards Bureau, Shellfish Consumer Co., Ltd. Printed invention description (1) The present invention relates to a radio frequency power amplifier ', and particularly to a radio frequency power amplifier with high efficiency and large gain range control> Large device and its control method. Generally speaking, RF power amplifiers are used in wireless communication systems to amplify and transmit signals. The design of RF power amplifiers requires high output power and high efficiency, and it is suitable for use in various places. The communication distance also requires that it can provide wide range gain control of output power 'to avoid unnecessary power consumption β currently used in monolithic microwave integrated circuit (MMIC) radio frequency The output power control method of the power amplifier has the following items: (1) power synthesis method, (2) power attenuation method, (3) UBIC method (Unbalanced Mas C_ascode), (4) light pole voltage control method, and (5) Gate voltage control mode. Each of the above methods has its advantages and disadvantages' is described below. One 1 (1) power combining mode ’is mainly to use the working combination of multiple power combiners (or power amplifiers) to achieve output power control. However, due to the limitation of the number and cost of power combiners, the number of power combiners has its limit. Therefore, there are only a few options for the output power in this way, and the control circuit is quite complicated. Β (2) Power attenuation The method is to add a power attenuator in the radio frequency circuit and directly reduce the output power to achieve the purpose of output power control. However, in practical applications, I want to design a MMIC with a wide range of power reduction capabilities ’low loss and low cost attenuation (please read the precautions on the back before filling this page) -install-τ order
.VI 本紙張尺度適用中國國家棣準（CNS > A4規格（210X297公釐） A7 B7 經濟部中央梂準局貝工消費合作社印裝 五、發明説明（2 ) 器是相當困難的。 (3) UBIC方式’其主要係利用一共源極組態，場效電晶 體（common Source FET)與一共閘極組態場效電晶體 (common，gate FET)串連（casc〇de)成一級，再利用變化共 閘極組態場效電晶體之閘極電壓，藉以改變共源極組態 場效電晶體之汲極電流，以達到輸出功率控制之目的。 然而，此一方式的缺點為電路複雜度高，且因電路具有 高增益（高放大率）所以共源極組態場效電晶體和共閘極 組態場效電晶體間之阻抗匹配不易，故而容易振盪不穩 定，同時電路成本高。 (4) 汲極電壓控制方式，其主要係在射頻功率電晶體 電源輸入端’加上一個大尺吋的電源控制電晶^，藉以 變化閘極電廢以改變射頻功率電晶趙之汲極電虔電流， 以達到輸出功率控制之目的’然而此電路之成本卻相當高。 - (5) 閘極電壓控制方式，說明如下β 請參照第1圖，以閘極電壓控制方式運作之射頻功 率放大器電路，其主要係由一輸入級放大器、一中間級（或 驅動級）放大器、和一功率輸出級放大器，三級放大器依 序串接而成，上述三級放大器係分別由RF功率電晶體 Q1〜Q3配合偏壓電路所形成，其中偏壓源Vgl〜Vg3係分 別用以偏麼功率電晶體Q1〜Q3之閘極，以便分別調整功 率電晶體各級放大器的偏壓工作點，一般而言，係將輸 入級放大器偏壓成為A或AB類（class A or AB)放大器以 請 先 聞- 面 之 注.VI This paper size is applicable to China National Standards (CNS > A4 size (210X297 mm) A7 B7 Printing by the Bayou Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention (2) It is quite difficult. (3) ) UBIC method 'It mainly uses a common source configuration, a field source transistor (common source FET) and a common gate configuration field effect transistor (common, gate FET) are connected in series (cascode), and then The gate voltage of the field effect transistor is changed by changing the common gate configuration to change the drain current of the field effect transistor of the common source configuration to achieve the purpose of output power control. However, the disadvantage of this method is that the circuit is complicated High degree of resistance, and because the circuit has high gain (high amplification), the impedance matching between the common source configuration field effect transistor and the common gate configuration field effect transistor is not easy, so it is easy to oscillate and unstable, and the circuit cost is high (4) The drain voltage control method is mainly based on the RF power transistor power input terminal plus a large-sized power control transistor ^ to change the gate power waste to change the RF power transistor Zhao Zhiji Polar electric current, In order to achieve the purpose of output power control ', however, the cost of this circuit is quite high.-(5) Gate voltage control method, as described below β Please refer to Figure 1, RF power amplifier circuit that operates under gate voltage control mode, which It is mainly composed of an input stage amplifier, an intermediate stage (or driver stage) amplifier, and a power output stage amplifier. The three stage amplifiers are connected in series. The three stage amplifiers are respectively matched by RF power transistors Q1 ~ Q3. A bias circuit is formed, where the bias sources Vgl ~ Vg3 are used to bias the gates of the power transistors Q1 ~ Q3, respectively, so as to adjust the bias operating points of the amplifiers of the power transistors at different levels. Generally, Bias the input stage amplifier into a Class A or AB amplifier
I 旁 裝 訂 私紙張尺度適用中國國家捸準（CNS ) A4规格（210X297公釐 經濟部中央揉準局負工消費合作社印製 A7 B7 五、發明説明（3 ) 做為初級之放大’帀功率輸出級放大器係偏壓成為AB 類放大器。第1囫所示之射頻功率放大器電路.，係藉由 變化調整Q1-Q3閘極偏壓之大小，進而改變射頻功率放 大器之輸·出電流之大小，進而將輸入之射頻信號之 功率放大而得到所須之射頻輸出功率。另外，一位準控 制線路（Level Voltage Control ，簡稱為LVC)，其輸出 耦接至Vgl〜Vg3之輸入端點，係用以提供微調控制之 用。 . r 上述控制方法雖然簡單，但是因為RF功率電晶體之 Vgs電壓，其可控制之變化範圍很小，故不易獲得大範 圍輸出功率之微調控制。又因一般功率輸出級係為AB 類放大器所以其一直^持在導通之狀態所以相當地消耗 電流’而且在無射頻信號輸入時，易於將各放大級間之 雜訊予以放大輸出。 本發明係為解決上述習知技術之缺點而提供一種高 效率及大範圍輸出功率控制之射頻功率放大器，將其功 率輸出級的功率電晶體適當加以偏壓，以使得功率輸出 級之放大器成為C類放大器’且配合改變媒動級的功率 電晶體之閘極電壓，使驅動級可以達到一大範圍變化且 大功率輸出訊號，利用此一訊號，得以直接驅動直流偏 壓已關閉之省電高效率c類功率輸出級，而得到高效率、 大範圍輸出功率控制、高穩定度、高線性微調控制、低 耗電流與低成本的射頻功率放大器。 為達成上述之目的’本發明之一種高效率和高範圍 本紙張尺度逋用中國國家橾準（CNS、A以β -------^丨裝------：訂丨-----必 I·' (請先聞讀背面.5-注意事項再填寫本頁) 5 經濟部中央橾準局員工消費合作社印ft A7 __________B7_五、發明説明（4) 增益控制之射頻放大器，包括：一第一級放大器，包含 一第一功率電晶想、一第一偏壓電路、以及一，第一偏壓 源，其中上述第一功率電晶體之汲/源極之一端耦接至一 電源節點其没/源之另一端耦接至一參考接地節點，上 述第一偏壓源為一固定值經上述第一偏壓電路而提供上 述第一功率電晶體之閘極偏壓，藉以使上述第一級放大 器成為A類或AB類放大器，一信號耦接至上述第一功 r ·* 率電晶體之閘極再經上述第一級放大器放大後由第一功 率放大器之没極輸出；一第二級放大器，包含一第二功 率電晶體、一第二偏壓電路、以及一第二偏壓源，其中 上述第二功率電晶體之汲/源極之一端耦接至上述電源 節點，其汲/源之另一端耦接至上述參考接地節點，上述 第二偏壓源經上述第二偏壓電路而提供上述第二功率電 晶艎之閘極偏壓，藉由改變上述第二偏壓源之電壓值以 便調整上述第一功率電晶體導通時汲極電流之大小，上 述第一級放大器之輪出耦接至上述第二功率電晶體之閘 極經上述第一級放大器放大後由上述第二功率放大器之 汲極輸出，此輸出為一大範圍變化且大輸出功率訊號； 以及，一第二級放大器，包含一第三功率電晶體、一第 三偏壓電路、以及一第三偏壓源，其中上述第三功率電 晶體之汲/源極之一端耦接至上述電源節點，其汲/源之另 一端耦接至上述參考接地節點，上述第三偏壓源為一固 疋值經上述第二偏壓電路而提供上述第一功率電晶體之 閘極偏壓，藉以使上述第三級放大器成為c類放大器’ ____ 6 本紙張尺度適用中國國家揉準（CNS ) A4規格（2I0X297公釐） (請先W讀背面之注意事項再填寫本頁) 衮· .訂 -· 經濟部中央樣準局貝工消費合作社印裝 五、發明説明（5 ) 上述第二級放大器之輸出相接至上述第三功 閘極’經上述第三級放大器放大後由上述第三功率曰放大 器之汲極輸出。 平狹大 另外-，上述第二級放大器中更可包括一位準控制裝 置耗接於上述第二功率電晶體之閘極，此位準控制展置 可由外加所須控制範圍之輸入電壓，轉換成所須之不同 輸出電壓準位，用以微調上述第二功率電晶趙導通時之 >及極電流。 為讓本發明之上述目的、特徵、和優點能更明顯易 僅，下文特舉出若干較佳之實施例，並配合所附囷式， 做詳細說明如下。 圖式之簡單說明： 第1圖係顯示以傳統技術申，使用閘極電壓控制方 式運作之射頻功率放大器的電路圖。 第2圖係顯示依據本發明之高效率和高範圍增益控 制之射頻放大器的電路圖。 第3A圖係表示’在頻率為9〇〇 MHz下，第二偏壓源 Vg2之電壓變化對應輸出功率p〇ut(dBm)與效率E(%)之結 果圖。 第3B圖係表示，在頻率為900 mHz下，第二偏壓 Vg2之電壓變化對應總消耗電流Id(mA)之結果圖。 第4A圖係表示，在頻率為915 MHz下，第二偏壓源 Vg2之電壓變化對應輸出功率pcut(dBm)與效率E(%)之結 果圖。 本紙張尺度適用中國國家揉準（CNS ) A4規格（210X297公釐） I» m »1 I ΙΊ 1 n u 1 I (請先聞诊背面之注$項再填寫本頁) |訂- 經濟部中央橾準局貝工消費合作社印製 A7 B7 五、發明説明（6 ) 第4B圖係表示’在頻率為915 MHz下，第二偏壓 Vg2之電壓變化對應總消耗電流Id(mA)之結果圊。 第5A圈係表示，在頻率為930 MHz下，第二偏壓源 Vg2之電壓變化對應輸出功率PDut(dBm)與效率E(%)之結 果囷。 第5B圖係表示，在頻率為930 MHz下，第二偏壓 Vg2之電壓變化對應總消耗電流id(mA)之結果圖。 符號說明： ·I Side-bound private paper standards are applicable to China National Standards (CNS) A4 specifications (210X297 mm printed by the Central Government Bureau of the Ministry of Economic Affairs and Consumer Cooperatives) A7 B7 V. Description of the invention (3) as a primary amplification '帀 Power output The stage amplifier is biased to become a class AB amplifier. The RF power amplifier circuit shown in Section 1 adjusts the gate bias voltage of Q1-Q3 to change the output and output current of the RF power amplifier. Furthermore, the power of the input RF signal is amplified to obtain the required RF output power. In addition, a level voltage control (LVC) output whose output is coupled to the input endpoints of Vgl ~ Vg3 is used In order to provide fine-tuning control.. R Although the above control method is simple, because the Vgs voltage of the RF power transistor has a small controllable change range, it is not easy to obtain fine-tuning control of a wide range of output power. Because of the general power output The stage is a class AB amplifier, so it is always in the on state, so it consumes considerable current, and it is easy to put each amplifier when there is no RF signal input. The noise between stages is amplified and output. The present invention is to provide a high-efficiency and wide-range output power control RF power amplifier in order to solve the shortcomings of the above-mentioned conventional technology. The power transistor of the power output stage is appropriately biased. In order to make the amplifier of the power output stage become a class C amplifier, and cooperate with changing the gate voltage of the power transistor of the medium drive stage, the driver stage can achieve a wide range of changes and high power output signals. Using this signal, it can be directly driven Power-saving and high-efficiency Class C power output stage with DC bias turned off, to obtain high efficiency, wide range output power control, high stability, high linear trimming control, low current consumption and low cost RF power amplifier. To achieve the above Purpose 'A high-efficiency and high-range paper size of the present invention uses the Chinese national standard (CNS, A with β ------- ^ 丨 installed --------: order 丨 ---- -必 I · '(Please read the back. 5-Notes before filling out this page) 5 Printed by the Consumer Cooperatives of the Central Government Bureau of the Ministry of Economic Affairs ft A7 __________B7_ V. Description of the invention (4) RF amplifier for gain control The device includes a first-stage amplifier including a first power transistor, a first bias circuit, and a first bias source, wherein one of the drain / source terminals of the first power transistor is described above. The other end of the source / source is coupled to a reference ground node, and the first bias source is a gate of the first power transistor with a fixed value through the first bias circuit Bias, so that the first-stage amplifier becomes a class A or AB amplifier, a signal is coupled to the gate of the first power r · * rate transistor, and then amplified by the first-stage amplifier, and then the first power amplifier Pole-less output; a second-stage amplifier including a second power transistor, a second bias circuit, and a second bias source, wherein one of the drain / source terminals of the second power transistor is coupled Connected to the power node, the other end of its sink / source is coupled to the reference ground node, the second bias source provides the gate bias of the second power transistor through the second bias circuit, By changing the voltage value of the second bias source to Adjusting the magnitude of the drain current when the first power transistor is turned on, the wheel output of the first-stage amplifier is coupled to the gate of the second power transistor, and the gate of the second power transistor is amplified by the first-stage amplifier, and then the gate of the second power amplifier is amplified. Drain output, which is a wide range and large output power signal; and a second-stage amplifier, including a third power transistor, a third bias circuit, and a third bias source, where One end of the drain / source of the third power transistor is coupled to the power supply node, and the other end of the drain / source of the third power transistor is coupled to the reference ground node. The third bias source is a fixed value that passes through the second The bias circuit provides the gate bias of the first power transistor to make the above-mentioned third-stage amplifier a Class C amplifier. ____ 6 This paper size applies to China National Standard (CNS) A4 (2I0X297 mm) (Please read the precautions on the reverse side before filling out this page). · .Order- · Printed by the Central Bureau of Standards, Ministry of Economic Affairs, Shellfish Consumer Cooperative, Ltd. 5. Description of Invention (5) The output of the above-mentioned second-stage amplifier is connected to the above The third power gate 'is amplified by the third-stage amplifier and output by the drain of the third power amplifier. In addition, the second stage amplifier can include a quasi-control device connected to the gate of the second power transistor. This level control display can be converted by adding an input voltage within the required control range. Different output voltage levels are required to fine-tune the above-mentioned second power transistor and the pole current when it is on. In order to make the above-mentioned objects, features, and advantages of the present invention more obvious and easy, several preferred embodiments are listed below, and the following formulas will be described in detail in conjunction with the attached formulas. Brief description of the diagram: Figure 1 is a circuit diagram showing an RF power amplifier that operates with gate voltage control using conventional technology. Fig. 2 is a circuit diagram showing a radio frequency amplifier with high efficiency and high range gain control according to the present invention. Figure 3A is a graph showing the results of the voltage change of the second bias source Vg2 at a frequency of 900 MHz corresponding to the output power pout (dBm) and the efficiency E (%). Figure 3B is a graph showing the result of the voltage change of the second bias voltage Vg2 corresponding to the total consumption current Id (mA) at a frequency of 900 mHz. Figure 4A is a graph showing the output voltage pcut (dBm) and efficiency E (%) corresponding to the voltage change of the second bias source Vg2 at a frequency of 915 MHz. This paper size applies to the Chinese National Standard (CNS) A4 (210X297 mm) I »m» 1 I ΙΊ 1 nu 1 I (please note the $ in the back of the diagnosis first and then fill out this page) | Order-Central Ministry of Economic Affairs APrinted by the Zhuhai Bureau Shellfish Consumer Cooperative A7 B7 V. Description of the invention (6) Figure 4B shows' the result of the voltage change of the second bias voltage Vg2 corresponding to the total consumption current Id (mA) at the frequency of 915 MHz 圊. Circle 5A indicates that at a frequency of 930 MHz, the voltage change of the second bias source Vg2 corresponds to the result of the output power PDut (dBm) and the efficiency E (%). Figure 5B is a graph showing the result of the change in voltage of the second bias voltage Vg2 corresponding to the total current consumption id (mA) at a frequency of 930 MHz. Symbol Description: ·
Ql、Q2、Q3〜功率電晶體，Bl、B2、B3〜偏壓電 路，VDD〜電源’ Vgl、Vg2、Vg3〜偏壓源，RFin〜射頻 輸入信號，LVC〜電壓控制裝置，Id〜總消耗電流，E〜效 率、P〇Ut〜輸出功率。 · 實施例： ， 第2圖係顯示依據本發明之高效率和高範圍增益控 制之射頻放大f的電路圖。本發明之射頻功率放大器， 其由三級放大器I、Π、m串接而成，下文將參照第2 囷作詳細之說明。 第一級放大器I，包含一第一功率電晶體（^、一第 -偏壓電路B1、以及一第一偏壓源Vgl。上述第一功率 電晶體Q1，例如為一„通道場效電晶體，其沒/源極之 -端經-阻抗路徑輕接至一電源VDD，其汲/源之另一端 柄接至-參考接地節點。上述第—偏麼源Vgl為一固定 值（在此實施例為-0.55V)經上述第一偏壓電路B1而提供 上述第-功率電晶趙Q1之閘極偏壓，藉以調整電晶體 ---------1 —Τ ^ 裝 111 I J 訂—— I ί·-Λ - » f (請先聞讀背面之注意事項再填寫本頁) 本紙張糊210χ297‘------ A7 B7 五、發明説明（7) Q1之偏壓工作點使得上述第一級放大器I成為A類或ab 類放大器。一射頻信號RFin耦接至上述第一功唓電晶體 Q1之閘極再經上述第一級放大器j進行初級放大後由第 一功率放A器之汲極輸出。 一第一級放大器II ’包含一第二功率電晶體Q2、一 第二偏壓電路B2、以及一第二偏壓源Vg2，其中上述第 二功率電晶體Q2，例如為！！通道場效電晶體，其汲/源 極之一端經一阻抗路徑耦接至上述電’源Vdd，其汲/源之 另一端耦接至上述參考接地節點，上述第二偏壓源Vg2 經上述第二偏壓電路而提供上述第二功率電晶體q2之 閘極偏壓，藉由改變上述第二偏壓源Vg2之電壓值以便 調整上述第二功率電晶體q2導通時汲極電流之大小以 達到控制輸出功库之目的，上述第一級放大器工之輸出相 接至上述第二功率電晶體Q2之閘極經上述第二級放大 器Π放大後由上述第二功率放大器之汲極輸出。其中， 更匕括位準控制裝置LVC，其輪入電壓介於3〜， 而輸出電壓約介於〇〜·2V之間，其與上述第二偏麼源並 聯叙接，藉變化施加於上述第二功率電晶體間極之電 壓’用以微調上述第二功率電晶趙導通時之沒極電流， 以獲得-大範圍變化且大功率輸出之訊號，而達到微調 控制輸出功率之目的。 -第三級放大器m ’包含一第三功率電晶趙⑺、 :第二電路B3、以及—第三偏㈣Vg3，其中上述 功率電晶趙Q3，例如為η通道場效電晶趙，其汲/ 本紙張尺度適用中國 ---.--.J---„-I^-------?!—-----^---- (請先聞讀背面4:-注$項再填寫本頁) 經濟部中央標準局貝工消費合作社印製 A7 B7 五、發明説明（8 ) 源極之一端經一阻抗路徑耦接至上述電源VDD，其汲/源 之另一端耦接至上述參考接地節點，上述第三偷壓源Vg3 為一固定值（在此實施例為-1.8V)經上述第三偏壓電路B3 而提供上-述第三功率電晶體之閘極偏壓，藉由改變上述 第三電晶體Q3之偏壓工作點，而使得上述第三級放大器 III成為C類放大器，上述第二級放大器II之大範圍變化 且大輸出功率訊號耦接至上述第三功率電晶體Q3之閘 極，直接驅動直流偏壓已關閉之省電高效率C類第三級 放大器，經上述第三級放大器III放大後由上述第三功率 放大器之汲極輸出，而成為射頻功率放大器之輸出。 本實例之實驗測試結果係在輸入射頻信號RFin之輸 入功率卩化為-3dBm，第一偏壓源Vgl為-0.55V，第三 偏壓源Vg3為-1.8V，以及VDD為3.3V之條件下加以量 測而得。第3A、4A、及5A圖分別表示，在頻率為900 MHz、915 MHz、以及930 MHz下，第二偏壓源Vg2之 電壓變化對應輸出功率PcJdBm)與效率E(%)之結果 圖。第3B、4B、及5B圖分別表示，在頻率為900 MHz、 915 MHz、以及930 MHz下，第二偏壓Vg2之電壓變化 對應消耗電流Id(mA)之結果圖。 如第3A、4A、及5A圖所示，本發明之射頻功率放 大器其輸出功率Pw可由+25 dBm大範圍變化至-25 dBm 且其對應於第二偏壓源Vg2之變化具有高度之線性，另 外在高功率輸出時其輸出效率亦可大於40%以上。所以 本發明之功率放大器確可以利用配合改變功率驅動級 10 本紙張尺度適用中國國家標準（CNS ) A4規格（2丨0·〆297公釐） (請先聞讀背面之注$項再填寫本頁) 裝. 訂 A7 ______B7_ 五、發明説明（10) 穩定度，且使電路之設計更單蜂化。 綜上所述，本發明之一種高效率及大範圍輸出功率 控制之射頻功率放大器’將其功率輸出級的功率電晶鱧 適當加以-偏壓，以使得功率輸出級之放大器成為C類放 大器，且配合改變驅動級（第二級放大器π)的功率電晶體 之閘極電壓，而得到高效率、大範圍輸出功率控制、高 穩定度、高線性微調控制、低耗電流與低成本的射頻功 率放大器。 Λ ， 雖然本發明已以一較佳實施例揭露如上，然其並非 用以限定本發明，任何熟悉本項技藝者，在不脫離本發 明之精神和範圍内所提出之修改和潤飾，均係涵括在本 發明之保護範圍内，而本發明之’保護範圍視後附之申請 專利範圍所界定者為準。 - ^1' n n n· J— n n n n n I T n -: n n I - · 0¾ Ί ————————— ^ * i , ' (請先閲^-背面1注意事項再填寫本頁) 經濟部t央標準局員工消费合作社印製Ql, Q2, Q3 ~ power transistors, Bl, B2, B3 ~ bias circuit, VDD ~ power supply 'Vgl, Vg2, Vg3 ~ bias source, RFin ~ RF input signal, LVC ~ voltage control device, Id ~ total Current consumption, E ~ efficiency, P0Ut ~ output power. Example: Fig. 2 is a circuit diagram showing a radio frequency amplifier f with high efficiency and high range gain control according to the present invention. The radio frequency power amplifier of the present invention is formed by connecting three stages of amplifiers I, Π, and m in series. The detailed description will be made below with reference to the second stage. The first-stage amplifier I includes a first power transistor (^, a first-bias circuit B1, and a first bias source Vgl. The first power transistor Q1 is, for example, a channel field effect transistor For the crystal, the -end of the source / source is lightly connected to a power source VDD, and the other end of the drain / source is connected to the -reference ground node. The first-biased source Vgl is a fixed value (here The example is -0.55V) The gate bias voltage of the first power transistor Zhao Q1 is provided through the first bias circuit B1 to adjust the transistor --------- 1 -T ^ 111 IJ Order—— I ί · -Λ-»f (Please read the notes on the back before filling this page) This paper paste 210χ297 '------ A7 B7 V. Description of the invention (7) Q1 bias The voltage operating point makes the first-stage amplifier I become a class A or ab amplifier. A radio frequency signal RFin is coupled to the gate of the first power transistor Q1, and then primary amplification is performed by the first-stage amplifier j. A drain output of a power amplifier A. A first-stage amplifier II ′ includes a second power transistor Q2, a second bias circuit B2, and a second bias source. Vg2, where the second power transistor Q2 is, for example, a channel field effect transistor, one end of its drain / source is coupled to the above-mentioned electrical source Vdd via an impedance path, and the other end of its drain / source is coupled To the reference ground node, the second bias source Vg2 provides the gate bias of the second power transistor q2 through the second bias circuit, and the voltage value of the second bias source Vg2 is changed so that Adjust the magnitude of the drain current when the second power transistor q2 is turned on to control the output power bank. The output of the first stage amplifier is connected to the gate of the second power transistor Q2 via the second stage. After the amplifier Π is amplified, it is output by the drain of the second power amplifier. Among them, the level control device LVC has a wheel-in voltage of 3 ~, and the output voltage is between 0 ~ · 2V. The second biased source is connected in parallel. By changing the voltage applied to the pole of the second power transistor, it is used to fine-tune the non-polar current when the second power transistor is turned on. Signal of power output, To achieve the purpose of fine-tuning the control of the output power.-The third-stage amplifier m 'includes a third power transistor Zhao Q, a second circuit B3, and a third bias Vg3, where the power transistor Zhao Q3 is, for example, an η channel. Field effect transistor Zhao, its standard / This paper size is applicable to China ---.--. J --- „-I ^ -------?! ------- ^ ---- ( Please read the back 4: -note $ before filling out this page) Printed by A7 B7, Shellfish Consumer Cooperative, Central Bureau of Standards, Ministry of Economic Affairs 5. Description of the Invention (8) One end of the source is coupled to the above-mentioned power supply VDD via an impedance path The other end of the sink / source is coupled to the reference ground node, and the third voltage stealing source Vg3 is a fixed value (-1.8V in this embodiment) provided by the third bias circuit B3. The gate bias voltage of the third power transistor is changed by changing the bias operating point of the third transistor Q3, so that the third-stage amplifier III becomes a class C amplifier, and the second-stage amplifier II is widely changed. And the high output power signal is coupled to the gate of the third power transistor Q3, which directly drives the power-saving high-efficiency class C third-stage amplifier with the DC bias turned off. Is, via the third amplifier stage III amplified output from the drain electrode of the third power amplifiers, and an output of the RF power amplifier. The experimental test results of this example are based on the condition that the input power of the input RF signal RFin is reduced to -3dBm, the first bias source Vgl is -0.55V, the third bias source Vg3 is -1.8V, and VDD is 3.3V. Measured below. Figures 3A, 4A, and 5A respectively show the results of the voltage change of the second bias source Vg2 corresponding to the output power PcJdBm) and the efficiency E (%) at frequencies of 900 MHz, 915 MHz, and 930 MHz. Figures 3B, 4B, and 5B show the results corresponding to the current consumption Id (mA) of the voltage change of the second bias voltage Vg2 at frequencies of 900 MHz, 915 MHz, and 930 MHz, respectively. As shown in Figures 3A, 4A, and 5A, the output power Pw of the RF power amplifier of the present invention can vary from +25 dBm to -25 dBm in a wide range, and its change corresponding to the second bias source Vg2 is highly linear. In addition, its output efficiency can be greater than 40% at high power output. Therefore, the power amplifier of the present invention can indeed be used to change the power drive level. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (2 丨 0 · 〆297 mm). (Please read the note on the back before filling in this. Page) Assembly. Order A7 ______B7_ 5. Description of the invention (10) Stability, and make the circuit design more simple. In summary, a high-efficiency and wide-range output power control RF power amplifier according to the present invention 'appropriately biases the power transistor of its power output stage, so that the amplifier of the power output stage becomes a class C amplifier. And in cooperation with changing the gate voltage of the power transistor of the driving stage (second stage amplifier π), high efficiency, wide range output power control, high stability, high linear trimming control, low current consumption and low cost RF power are obtained. Amplifier. Λ, although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any modifications and retouches proposed by those skilled in the art without departing from the spirit and scope of the present invention are all It is included in the scope of protection of the present invention, and the scope of protection of the present invention is determined by the scope of the attached patent application. -^ 1 'nnn · J— nnnnn IT n-: nn I-· 0¾ Ί ————————— ^ * i,' (Please read ^ -Notes on the back 1 before filling this page) Ministry of Economy Printed by the Consumer Standards Cooperative of the Central Bureau of Standards