KR100875201B1 - Cascode Structured Power Amplifier for Amplitude Modulation - Google Patents

Abstract

The wireless transmitter includes a frequency generator and a power amplifier for generating a carrier signal of a predetermined frequency. The power amplifier operates by receiving a power supply voltage having a predetermined magnitude, is biased based on the voltage level of the baseband signal, receives a carrier signal, and amplifies the carrier signal according to the biased state to generate a wireless signal. In this case, the power amplifier may include a bias unit generating a bias voltage according to the voltage level of the baseband signal. In addition, the baseband signal may be a binary amplitude shift keying signal.

Description

Cascode Power Amplifier For Amplitude Modulation

1 is a block diagram of a transmitter using a conventional linear power amplifier.

2 is a block diagram of a transmitter using a conventional polar modulation scheme.

3 is a block diagram illustrating a transmitting end according to an embodiment of the present invention.

4 is a circuit diagram illustrating a cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

5 is a circuit diagram illustrating a cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

6 is a circuit diagram illustrating a cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

7 is a circuit diagram illustrating a cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

8 is a circuit diagram illustrating a cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

9 is a circuit diagram illustrating a cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

10 is a circuit diagram illustrating a differential cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

11 is a circuit diagram illustrating a differential cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

12 is a circuit diagram illustrating a transmitter having a plurality of differential cascode power amplifiers and transmission line transformers including field effect transistors according to an embodiment of the present invention.

FIG. 13 is a circuit diagram illustrating a transmitter having a plurality of differential cascode power amplifiers and transmission line transformers including bipolar transistors according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

31 power amplifier 41 common source transistor

42: common gate transistor 43: bias portion

51: common emitter transistor 52: common base transistor

53: bias part

The present invention relates to a high frequency power amplifier, and more particularly to a high frequency power amplifier for amplitude modulation.

The transmitter of the wireless communication system modulates a baseband signal having information to be transmitted to be suitable for wireless communication, amplifies the modulated signal, and transmits the modulated signal to the antenna. The modulation method and the amplification method are closely related to each other. For example, if the baseband signal is modulated by an amplitude modulation method, it is appropriate to use a linear power amplifier.

1 is a block diagram of a transmitter using a conventional linear power amplifier. Referring to FIG. 1, the transmitting end is a digital-to-analog converter (D / A) 11, 12, a low pass filter (LPF) 13, 14, a mixer 15, 16, and a band pass filter (BPF) 17. ) And a linear power amplifier (PA) 18. The digital-analog converters 11 and 12 and the low pass filters 13 and 14 convert the in-phase signal I and the quadrature signal Q, which are discrete signals, into analog signals, respectively, to perform low pass filtering. The mixers 15 and 16 and the bandpass filter 17 mix them with the cosine signals and filter the bandpass. The linear power amplifier 18 amplifies the filtered signal to generate an RF signal and transmit it to the antenna 19.

It is generally known that linear power amplifiers do not exceed 50% power efficiency. However, when the impedance of the power amplifier is adjusted by power matching to increase the power efficiency, the voltage standing wave ratio VSWR becomes worse because the difference between the impedance of the antenna is increased. It is also inefficient, as the power amplifier consumes power even when the baseband signal has no information.

2 is a block diagram of a transmitter using a conventional polar modulation scheme. Referring to FIG. 2, a polar modulation transmitter may include a polar converter 21, an amplitude chain 22, a phase chain 23, and a voltage supply unit (PWR supply). 24, a frequency generator (PLL) 25 and a power amplifier (PA) 26.

The baseband signal may be an in-phase (I) signal and a quadrature (Q) signal, and the I and Q signals may be discrete signals. The polar converter 21 extracts an amplitude signal r having amplitude information and a phase signal? Having phase information from the baseband signal.

Although the amplitude signal r and the phase signal φ are synchronized, they are processed through different paths. In the amplitude signal chain 22, the amplitude signal r is amplified with a predetermined gain, and the amplified amplitude signal r 'is provided to the voltage supply 24. The voltage supply unit 24 generates a power supply voltage that varies according to the amplitude signal r, and supplies the power supply voltage to the power amplifier 26. In the phase signal chain 23, the phase signal φ is modulated to a desired magnitude, and the modulated phase signal φ 'is provided to the frequency generator 25. The frequency generator 25 generates a carrier signal having a frequency varying according to the modulated phase signal φ 'and supplies it to the power amplifier 26. The power amplifier 26 amplifies the carrier signal according to a variable power supply voltage and transfers the carrier signal to the antenna 27.

Unlike the transmitting end of FIG. 1, the polarization type transmitting end does not need to use a linear power amplifier because the magnitude of the output signal of the power amplifier does not vary linearly with the size of the signal input to the power amplifier. For example, if the baseband signal is a signal modulated by an amplitude shift modulation scheme, a switching power amplifier switched according to the amplitude signal may be used. Switching power amplifiers are known to be more power efficient than linear power amplifiers. In addition, since a frequency mixer is not required and the number of low pass filters or band pass filters can be reduced, it may be advantageous in terms of power consumption, size, and noise.

Since the polarization-transmitter modulates the baseband signal by controlling the magnitude of the supply voltage supplied to the power amplifier, a DC-DC converter or a low-drop-out (LDO) for changing the supply voltage at the voltage supply unit. A rectifier such as This may not improve power consumption or size as expected. In addition, switching noise generated in the DC-DC converter may be disadvantageous in terms of noise.

Thus, there is still a need for a transmit stage structure using a nonlinear power amplifier that does not use a DC-DC converter or rectifier.

It is an object of the present invention to provide a transmitter having a high frequency power amplifier which does not require a DC-DC converter or a rectifier.

The wireless transmitter according to an embodiment of the present invention includes a frequency generator and a power amplifier for generating a carrier signal of a predetermined frequency. The power amplifier operates by receiving a power supply voltage having a predetermined magnitude, is biased based on a voltage level of a baseband signal, receives the carrier signal, and amplifies the carrier signal according to the biased state to generate a wireless signal. . The power amplifier may include a bias unit configured to generate a bias voltage according to the voltage level of the baseband signal. The baseband signal may be a binary amplitude shift keying signal.

A wireless transmitter according to another embodiment of the present invention includes a frequency generator, a bias unit, a common source transistor, and at least one common gate transistor. The frequency generator generates a carrier signal of a predetermined frequency. The bias unit generates a bias voltage according to the voltage level of the baseband signal. The common source transistor has a common source structure and receives the carrier signal at a gate. The common gate transistor is connected to the common source transistor in a cascode manner, receives the bias voltage at a gate, and outputs a wireless signal at a drain. The bias unit may be a level shifter for changing the voltage level of the baseband signal to a predetermined voltage level, or may be a pulse shaping circuit for pulse-shaping the waveform of the baseband signal to have a predetermined frequency characteristic. The common gate transistor is a plurality of common gate transistors connected in series, and the bias voltage may be applied to at least one of the gates of the plurality of common gate transistors.

In an embodiment, a second bias unit generates a second bias voltage according to a voltage level of the baseband signal, a second common source transistor having a common source structure, and receiving the wireless signal from a gate, and the second common source transistor. And at least one second common gate transistor connected in a cascode manner, receiving the second bias voltage at a gate, and outputting a second wireless signal at a drain.

The wireless transmitter according to another embodiment of the present invention includes a frequency generator, a bias unit, a common emitter transistor and at least one common base transistor. The frequency generator generates a carrier signal of a predetermined frequency. The bias unit generates a bias voltage according to the voltage level of the baseband signal. The common emitter transistor has a common emitter structure and receives the carrier signal at a base. The common base transistor is connected to the common emitter transistor in a cascode manner, receives the bias voltage at a base, and outputs a wireless signal at a collector. The bias unit may be a level shifter for changing the voltage level of the baseband signal to a predetermined voltage level, or may be a pulse shaping circuit for pulse-shaping the waveform of the baseband signal to have a predetermined frequency characteristic. The common base transistor is a plurality of common base transistors connected in series, and the bias voltage may be applied to at least one of the bases of the plurality of common base transistors.

In an embodiment, a second bias unit generates a second bias voltage according to a voltage level of the baseband signal, a second common emitter transistor having a common emitter structure, and receiving the wireless signal from a base, and the second common. The display device may further include at least one second common base transistor connected to the emitter transistor in a cascode manner, receiving the second bias voltage at a base, and outputting a second wireless signal at a collector.

A wireless transmitter according to another embodiment of the present invention includes a frequency generator, a bias unit, a pair of common source transistors and at least a pair of common gates. The pair of common source transistors have a common source structure, and differentially receive the carrier signal at each gate. The at least one pair of common gate transistors are cascoded with the common source transistor, respectively, and receive the bias voltage at a gate, and differentially output a wireless signal at a drain. The bias unit may be a pulse shaping circuit for shaping the waveform of the baseband signal to have a predetermined frequency characteristic. The common gate transistor is a plurality of common gate transistors connected in series, and the bias voltage may be applied to at least one gate of the plurality of common gate transistors.

A wireless transmitter according to another embodiment of the present invention includes a frequency generator, a bias unit, a pair of common emitter transistors and at least a pair of common bases. The pair of common emitter transistors have a common emitter structure and differentially receive the carrier signal at each base. The at least one pair of common base transistors are cascoded with the common emitter transistor, respectively, and receive the bias voltage at a base, and differentially output a wireless signal at a collector. The bias unit may be a pulse shaping circuit for shaping the waveform of the baseband signal to have a predetermined frequency characteristic. The common base transistor is a plurality of common base transistors connected in series, and the bias voltage may be applied to at least one base of the plurality of common base transistors.

A wireless transmitter according to another embodiment of the present invention includes a frequency generator for generating a carrier signal of a predetermined frequency, at least two power amplifiers including field effect transistors, and two or more transmission line transformers. The power amplifier operates by receiving a power supply voltage having a predetermined magnitude, is biased based on a voltage level of a baseband signal, differentially inputs the carrier signal, and amplifies the carrier signal according to the biased state to differential the wireless signal. Create The two or more transmission line transformers are each connected to the outputs of the at least two power amplifiers, each having a 1: 1 turns ratio, and connected in series with each other. In this case, the power amplifier has a bias unit for generating a bias voltage according to the voltage level of the baseband signal, a common source structure, a pair of common source transistors differentially inputting the carrier signal at each gate, and At least one pair of common gate transistors connected to the common source transistor in a cascode manner, respectively receiving the bias voltage at a gate, and differentially outputting a wireless signal at a drain. The bias unit may be a pulse shaping circuit for pulse shaping the waveform of the baseband signal to have a predetermined frequency characteristic.

A wireless transmitter according to another embodiment of the present invention includes a frequency generator for generating a carrier signal of a predetermined frequency, at least two power amplifiers including bipolar transistors, and two or more transmission line transformers. The power amplifier operates by receiving a power supply voltage having a predetermined magnitude, is biased based on a voltage level of a baseband signal, differentially inputs the carrier signal, and amplifies the carrier signal according to the biased state to differential the wireless signal. Create The two or more transmission line transformers are each connected to the outputs of the at least two power amplifiers, each having a 1: 1 turns ratio, and connected in series with each other. The power amplifier has a bias unit and a common emitter structure for generating a bias voltage according to the voltage level of the baseband signal, and a pair of common emitter transistors differentially input the carrier signal at each base. And a common base transistor connected to the common emitter transistor in a cascode manner, respectively receiving the bias voltage from a base, and differentially outputting a wireless signal from a collector. The bias unit may be a pulse shaping circuit for pulse shaping the waveform of the baseband signal to have a predetermined frequency characteristic.

With respect to the embodiments of the present invention disclosed in the text, specific structural to functional descriptions are merely illustrated for the purpose of describing embodiments of the present invention, embodiments of the present invention may be implemented in various forms and It should not be construed as limited to the embodiments described in.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosure form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for the components.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between. Other expressions describing the relationship between components, such as "between" and "immediately between," or "neighboring to," and "directly neighboring to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is described, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention.

3 is a block diagram illustrating a transmitting end according to an embodiment of the present invention.

Referring to FIG. 3, the transmitting end includes a nonlinear switching power amplifier 31. The power amplifier 31 receives a baseband signal modulated by a predetermined modulation scheme and a carrier signal having a predetermined frequency, and operates by receiving a power supply voltage having a predetermined magnitude. The baseband signal is used as a bias voltage of the power amplifier 31, and the power amplifier 31 amplitude modulates the amplitude of the carrier signal according to the bias voltage and outputs the amplitude as a radio signal RF OUT.

Amplitude-shift-keying (ASK) is suitable for baseband signals input to nonlinear power amplifiers because it is amplitude modulation and does not require high linearity. A case of transmitting a baseband signal having a binary amplitude shift modulated to have an amplitude of 0 or 1 will be described as an example. When the level of the baseband signal corresponds to the binary value 0, since the bias voltage of the power amplifier becomes the voltage level corresponding to the binary value 0, the amplitude of the radio signal has a relatively large swing width. When the level of the baseband signal corresponds to the binary value 1, the bias voltage of the power amplifier is also the voltage level corresponding to 1, so that the amplitude of the radio signal has a relatively small swing width.

In the transmitter of FIG. 1, a binary ASK signal of 0 or 1 input to the linear power amplifier is amplified and output according to a predetermined gain. In general, in a transmitter using a linear power amplifier, a mixer, a filter, and the like consume power regardless of the amplitude of the baseband signal. In the transmitting terminal of FIG. 2, a voltage corresponding to 0 V or VDD is supplied to the power supply voltage of the power amplifier according to an input signal having an amplitude of 0 or 1. Although there are no mixers or filters, it is necessary to have a DC-DC converter or a rectifier in order to convert the power supply voltage level, and is vulnerable to switching noise of a power supply supplying a large current. In contrast, in the transmitting end of FIG. 3, a mixer, a filter, and the like are not necessary, and noise is also reduced since the power supply is not switched.

4 is a circuit diagram illustrating a cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

Referring to FIG. 4, the cascode power amplifier has a structure in which a common source transistor 41 and a common gate transistor 42 are cascoded. The common source transistor 41 is connected in a common source manner, and receives a carrier signal provided from a frequency generator (not shown) at a gate. The common gate transistor 42 is connected in a common gate manner, receives a bias voltage at a gate, a source is connected to a drain of the common source transistor 41, and at a drain, a radio signal RF OUT. Outputs

The baseband signal is converted into a bias voltage in the bias unit 43 and applied to the gate of the common gate transistor 42. When the level of the baseband signal is zero, the common gate transistor 42 almost blocks the current path of the cascode current amplifier, and at the drain, a radio signal having a relatively large amplitude with a frequency of the carrier signal is output. . When the level of the baseband signal corresponds to 1, the common gate transistor 42 is turned on and causes the cascode current amplifier to act like a linear large power amplifier, at the drain having the frequency of the carrier signal and having a relatively small amplitude. The radio signal is output.

The bias section 43 converts the baseband signal to have a voltage level suitable for the common gate transistor 42. In one embodiment, the bias unit 43 may be implemented as a level shifter according to the relative high and low of the voltage level of the baseband signal and the voltage level of the bias voltage, or implemented as a voltage divider. May be In another embodiment, the bias unit 43 may be a pulse shaping circuit or a pre-distortion circuit that pre-adjusts the waveform of the baseband signal to reduce frequency components unnecessary for the wireless signal. . In another embodiment, the bias unit 43 may be an inverter operating between a predetermined supply voltage and a base voltage other than VDD.

An inductor 44 connected between the drain of the common gate transistor 42 and the high voltage power supply VDD serves as a load of the common gate transistor 42 in the cascode power amplifier, while switching to a radio signal RF OUT. It also has the effect of blocking the transmission of high frequency noise to the power supply.

Inductor 44 may be viewed as part of a transmission line transformer (TLT, not shown) connected to the cascode power amplifier. Since the wireless signal cannot be larger than the size of the high voltage power supply (VDD), the output of the wireless signal can be increased by connecting a transmission line transformer to the next stage of the power amplifier.

5 is a circuit diagram illustrating a cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

Referring to FIG. 5, the cascode power amplifier has a structure in which a common emitter transistor 51 and a common base transistor 52 are cascoded. The common emitter transistor 51 is connected in a common emitter manner and receives a carrier signal provided from a frequency generator (not shown) at the base. The common base transistor 52 is connected in a common base manner, receives a bias voltage at the base, the emitter is connected to the collector of the common emitter transistor 51, and the radio signal RF OUT at the collector. Outputs

The baseband signal is converted into a bias voltage in the bias unit 53 and applied to the base of the common base transistor 52. When the level of the baseband signal is zero, the common base transistor 52 almost cuts off the current path of the cascode current amplifier, and at the base, a radio signal having a relatively large amplitude with the frequency of the carrier signal is output. do. When the level of the baseband signal is equal to 1, the common base transistor 52 is turned on and causes the cascode current amplifier to act like a linear large power amplifier, with the frequency of the carrier signal at the base having a relatively small amplitude The radio signal is output.

The bias section 53 converts the baseband signal to have a voltage level suitable for the common base transistor 52. In one embodiment, the bias unit 53 may be implemented as a level shifter as a relative high and low voltage level of the baseband signal and the voltage level of the bias voltage, or may be implemented as a voltage divider. May be In another embodiment, the bias unit 53 may be a pulse shaping circuit or a pre-distortion circuit that pre-adjusts the waveform of the baseband signal to reduce frequency components unnecessary for the wireless signal. . In another embodiment, the bias section 53 may be an inverter operating between a predetermined supply voltage and a base voltage other than Vdd.

An inductor 54 connected between the collector of the common base transistor 52 and the high voltage power supply VDD serves as a load of the common base transistor 52 in the cascode power amplifier, and due to the switching radio signal RF OUT It also has the effect of blocking the transmission of high frequency noise to the power supply.

Inductor 54 may be viewed as part of a transmission line transformer (TLT, not shown) connected to the cascode power amplifier. Since the wireless signal cannot be larger than the size of the high voltage power supply (VDD), the output of the wireless signal can be increased by connecting a transmission line transformer to the next stage of the power amplifier.

6 is a circuit diagram illustrating a cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

Referring to FIG. 6, the cascode power amplifier has a plurality of common gate transistors 61 and 62, and each receives a corresponding bias voltage. At this time, at least one of the plurality of bias voltages is a bias voltage generated from the baseband signal.

7 is a circuit diagram illustrating a cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

Referring to FIG. 7, the cascode power amplifier has a plurality of common base transistors 71 and 72, and receives corresponding bias voltages, respectively. At this time, at least one of the plurality of bias voltages is a bias voltage generated from the baseband signal.

8 is a circuit diagram illustrating a cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

Referring to FIG. 8, the cascode power amplifier includes a plurality of cascode power amplifier stages. The first cascode stage 81 receives a carrier signal and a bias voltage and outputs a modulated signal. The second cascode stage 82 receives a modulated signal and a bias voltage and outputs a radio signal.

9 is a circuit diagram illustrating a cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

9, a cascode power amplifier includes a plurality of cascode power amplifier stages. The first cascode stage 91 receives a carrier signal and a bias voltage and outputs a modulated signal, and the second cascode stage 92 receives a modulation signal and a bias voltage and outputs a radio signal.

10 is a circuit diagram illustrating a differential cascode power amplifier including a field effect transistor according to an embodiment of the present invention.

Referring to FIG. 10, the cascode power amplifier includes a pair of common source transistors 101 and 102 and a pair of common gate transistors 103 and 104.

A bias signal is commonly applied to the gates of the common gate transistors 103 and 104 similarly to the case of FIG. 4. The carrier signal is differentially input to the gates of the common source transistors 101 and 102, and the radio signal RF OUT is differentially output to the drains of the common gate transistors 103 and 104. Since the operation of the cascode power amplifier is similar to the operation of the cascode power amplifier of FIG.

The bias unit 105 converts the baseband signal to have a voltage level suitable for the common gate transistors 103 and 104. The bias unit 105 may be a level shifter, a voltage divider, a pulse shape circuit, or a line distortion circuit.

In some embodiments, the common gate transistors 103 and 104 may be a plurality of transistors to which a plurality of bias voltages are applied. At this time, at least one of the plurality of bias voltages is a bias voltage generated from the baseband signal.

11 is a circuit diagram illustrating a differential cascode power amplifier including a bipolar transistor according to an embodiment of the present invention.

Referring to FIG. 11, the cascode power amplifier includes a pair of common emitter transistors 111 and 112 and a pair of common base transistors 113 and 114.

A bias signal is commonly applied to the bases of the common base transistors 113 and 114 similarly to the case of FIG. 5. The carrier signal is differentially input to the base of the common emitter transistors 111 and 112, and the radio signal RF OUT is differentially output from the collector of the common base transistors 113 and 114. Since the operation of the cascode power amplifier is similar to that of the cascode power amplifier of FIG. 5, the description thereof is omitted.

The bias unit 115 converts the baseband signal to have a voltage level suitable for the common base transistors 113 and 114. The bias unit 115 may be a level shifter, a voltage divider, a pulse shape circuit, or a line distortion circuit.

In some embodiments, the common base transistors 113 and 114 may be a plurality of transistors to which a plurality of bias voltages are applied. At this time, at least one of the plurality of bias voltages is a bias voltage generated from the baseband signal.

12 is a circuit diagram illustrating a transmitter having a plurality of differential cascode power amplifiers and transmission line transformers including field effect transistors according to an embodiment of the present invention.

Referring to FIG. 12, the transmitter includes two differential cascode power amplifiers 121 and 122 and a 1: 2 transmission line transformer 124.

The two differential cascode power amplifiers 121, 122 have common source transistors and common gate transistors similar to the circuit of FIG. The bias signal generated by the bias unit 123 based on the baseband signal is commonly applied to the gates of the common gate transistors 1213, 1214, 1223, and 1224, similarly to the case of FIG. 6. The carrier signal is differentially input to the gates of the common source transistors 1211, 1212, 1221, 1222. The operation of the cascode power amplifier is similar to that of the cascode power amplifier of FIGS. 4 and 10, and thus description thereof is omitted.

The bias unit 123 converts the baseband signal to have a voltage level suitable for the common gate transistors 1213, 1214, 1223, and 1224. The bias unit 123 may be a level shifter, a voltage divider, a pulsed circuit, or a line distortion circuit.

According to an embodiment, the common gate transistors 1213, 1214, 1223, and 1224 may be a plurality of transistors connected in series to receive a plurality of bias voltages. At this time, at least one of the plurality of bias voltages is a bias voltage generated from the baseband signal.

The wireless signal differentially output from the drains of the common gate transistors 1213, 1214, 1223, and 1224 is applied to the transmission line transformer 124. The transmission line transformer 124 has a form in which two transformers each having a turns ratio of 1: 1 are connected in series. Using such a voltage-combining transformer results in the same effect as connecting one transformer having a turns ratio of 1: 2.

FIG. 13 is a circuit diagram illustrating a transmitter having a plurality of differential cascode power amplifiers and a transmission line transformer including a bipolar transistor according to an embodiment of the present invention.

Referring to FIG. 13, the transmitter includes two differential cascode power amplifiers 131 and 132 and a 1: 2 transmission line transformer 134.

The two differential cascode power amplifiers 131, 132 have common emitter transistors and common base transistors similar to the circuit of FIG. 7. The bias signal generated by the bias unit 133 based on the baseband signal is commonly applied to the bases of the common base transistors 1313, 1314, 1323, and 1324 similarly to the case of FIG. 7. The carrier signal is differentially input to the base of the common emitter transistors 1311, 1312, 1321, 1322. Since the operation of the cascode power amplifier is similar to the operation of the cascode power amplifier of FIGS. 5 and 11, description thereof is omitted.

The bias unit 133 converts the baseband signal to have a voltage level suitable for the common base transistors 1313, 1314, 1323, and 1324. The bias unit 133 may be a level shifter, a voltage divider, a pulse shape circuit, or a line distortion circuit.

According to an embodiment, the common base transistors 1313, 1314, 1323, and 1324 may be a plurality of transistors connected in series to which a plurality of bias voltages are applied. At this time, at least one of the plurality of bias voltages is a bias voltage generated from the baseband signal.

The wireless signal differentially output from the collectors of the common base transistors 1313, 1314, 1323, and 1324 is applied to the transmission line transformer 134. The transmission line transformer 134 has a form in which two transformers each having a turns ratio of 1: 1 are connected in series. Using such a voltage-combining transformer results in the same effect as connecting one transformer having a turns ratio of 1: 2.

The circuit of the present invention is applicable to a transmitting terminal such as a portable communication device, such as a mobile phone, a PCS phone, a wireless LAN transmitter, an RF reader, and the like.

The high frequency power amplifier according to an embodiment of the present invention can switch the power amplifier without using a DC-DC converter or an LDO rectifier. In addition, the carrier signal can be modulated according to the information of the baseband signal without using a mixer or a filter. Therefore, there is no problem of switching noise, and the chip area and power consumption can be reduced.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (27)

A frequency generator for generating a carrier signal of a predetermined frequency; And And a power amplifier configured to operate by receiving a power supply voltage having a predetermined magnitude, biased based on a voltage level of a baseband signal, and receiving the carrier signal and amplifying the carrier signal according to the biased state to generate a wireless signal. Wireless transmitting end, characterized in that. The wireless transmitter of claim 1, wherein the power amplifier includes a bias unit configured to generate a bias voltage according to a voltage level of the baseband signal. delete A frequency generator for generating a carrier signal of a predetermined frequency; A bias unit generating a bias voltage according to the voltage level of the baseband signal; A common source transistor having a common source structure and receiving the carrier signal at a gate; And And at least one common gate transistor connected to the common source transistor in a cascode manner, receiving the bias voltage at a gate, and outputting a wireless signal at a drain. 5. The wireless transmitter of claim 4, wherein the bias unit is a level shifter for changing a voltage level of the baseband signal to a predetermined voltage level. 5. The wireless transmitter of claim 4, wherein the bias unit is a pulse shaping circuit for pulse shaping the waveform of the baseband signal to have a predetermined frequency characteristic. 5. The wireless transmitter of claim 4, further comprising at least one common gate transistor connected in series with the common gate transistor, wherein a predetermined bias voltage is applied to the gates of the plurality of common gate transistors, respectively. The method of claim 4, wherein A second bias unit configured to generate a second bias voltage according to the voltage level of the baseband signal; A second common source transistor having a common source structure and receiving the wireless signal at a gate; And And at least one second common gate transistor connected to the second common source transistor in a cascode manner, receiving the second bias voltage at a gate, and outputting a second wireless signal at a drain. Characterized in that the wireless transmitting end. A frequency generator for generating a carrier signal of a predetermined frequency; A bias unit generating a bias voltage according to the voltage level of the baseband signal; A common emitter transistor having a common emitter structure and receiving the carrier signal at a base; And And at least one common base transistor connected to the common emitter transistor in a cascode manner, receiving the bias voltage at a base, and outputting a wireless signal at a collector. 10. The wireless transmitter of claim 9, wherein the bias unit is a level shifter for changing a voltage level of the baseband signal to a predetermined voltage level. 10. The wireless transmitter of claim 9, wherein the bias unit is a pulse shaping circuit for pulse shaping the waveform of the baseband signal to have a predetermined frequency characteristic. 10. The wireless transmitter of claim 9, further comprising at least one common base transistor connected in series with the common base transistor, wherein a predetermined bias voltage is applied to the bases of the plurality of common base transistors, respectively. The method of claim 9, A second bias unit configured to generate a second bias voltage according to the voltage level of the baseband signal; A second common emitter transistor having a common emitter structure and receiving the wireless signal at a base; And At least one second common base transistor connected to the second common emitter transistor in a cascode manner, receiving the second bias voltage at a base, and outputting a second wireless signal at a collector; Wireless transmitting end, characterized in that. delete delete delete A frequency generator for generating a carrier signal of a predetermined frequency; A bias unit generating a bias voltage according to the voltage level of the baseband signal; A pair of common emitter transistors having a common emitter structure and differentially inputting the carrier signal at each base; And And at least one pair of common base transistors connected to the common emitter transistors in a cascode manner, respectively receiving the bias voltage at a base, and differentially outputting a wireless signal at a collector. Sender. 18. The wireless transmitter of claim 17, wherein the bias unit is a pulse shaping circuit for pulse shaping the waveform of the baseband signal to have a predetermined frequency characteristic. 18. The wireless transmitter of claim 17, wherein the common base transistor is a plurality of common base transistors connected in series, and the bias voltage is applied to at least one of the bases of the plurality of common base transistors. delete delete delete delete A frequency generator for generating a carrier signal of a predetermined frequency; It operates by receiving a power supply voltage of a predetermined magnitude, is biased based on the voltage level of the baseband signal, differentially receives the carrier signal, amplifies the carrier signal according to the biased state to differentially generate a wireless signal, and a bipolar transistor At least two power amplifiers including; And And at least two transmission line transformers each connected to the outputs of the at least two power amplifiers, each having a 1: 1 turns ratio and connected in series with each other. The power amplifier of claim 24 wherein the power amplifier is A bias unit generating a bias voltage according to the voltage level of the baseband signal; A pair of common emitter transistors having a common emitter structure and differentially inputting the carrier signal at each base; And And at least one pair of common base transistors connected to the common emitter transistors in a cascode manner, respectively receiving the bias voltage at a base, and differentially outputting a wireless signal at a collector. Sender. 26. The wireless transmitter of claim 25, wherein the bias unit is a pulse shaping circuit for pulse shaping the waveform of the baseband signal to have a predetermined frequency characteristic. 27. The wireless transmitter of claim 25, wherein the common base transistor is a plurality of common base transistors connected in series, and the bias voltage is applied to at least one of the bases of the plurality of common base transistors.

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