TWI449328B - Power-amplifier circuit having improved efficiency - Google Patents

Description

Power amplifier circuit for improving efficiency

The present invention relates to a power amplifying circuit, and more particularly to a power amplifying circuit for improving efficiency.

In wireless communication systems, a power amplifier (PA) is an important component in the transmitter. Before the antenna is transmitted, the wireless signal needs to pass through the power amplifier to amplify to a comparable power level. The size of the power level determines the distance that the wireless signal is transmitted, and the efficiency of the power amplifier affects the battery power consumption of the electronic device (such as a mobile phone) having the transmitter.

Please refer to FIG. 1 , which is a schematic diagram of a general power amplifier PA. The power amplifier PA operates by receiving the DC power P _dc and converts the input power P _in into the output power P _out . The efficiency of the power amplifier PA is used to indicate how much of the input energy received by the power amplifier PA is represented by the output energy of the power amplifier PA. In other words, the efficiency can exhibit the power conversion capability of the power amplifier PA.

In general, efficiency can be divided into three types: Drain efficiency (η _D ), Power-added efficiency (η _PAE ), and Overall efficiency (η _T ).

The drain efficiency η _D is the ratio of the output power P _out to the DC power P _dc . The power added efficiency η _PAE is the ratio of the difference between the output power P _out and the input power P _in to the DC power P _dc . The overall efficiency η _T is the ratio of the output power P _out to the sum of the input power P _in and the DC power P _dc .

In the case where the output power of the power amplifier is the same, the higher the efficiency, the less input power is required, thereby reducing the power consumption of the battery. In addition, the higher the efficiency, the lower the heat dissipation of the power amplifier, so that the temperature of the electronic device is not easily increased during operation.

In view of this, how to improve the efficiency of the power amplifier is a problem that researchers in related fields are eager to improve.

In view of the above problems, the present invention provides a power amplifying circuit for improving efficiency, thereby solving the problem of the prior art to improve the efficiency of a power amplifier.

One embodiment of the present invention provides a power amplifying circuit for improving efficiency, comprising: a first power amplifier, a second power amplifier, a post-stage hybrid coupler, an impedance matching unit, and a rectifying unit.

The first power amplifier has an input and an output. The second power amplifier also has an input and an output.

The post-stage hybrid coupler includes a first input, a second input, an output, and an isolated end. The first input is electrically coupled to the output of the first power amplifier. The second input is electrically coupled to the output of the second power amplifier. The impedance matching unit is electrically connected to the isolation end. The rectifying unit is electrically connected to the impedance matching unit.

The input of the first power amplifier receives the first signal. The input of the second power amplifier receives the second signal. The second signal has a phase difference between the first signals.

The output of the subsequent stage hybrid coupler is for outputting an output signal corresponding to the output of the first power amplifier and the output of the second power amplifier. The isolated end of the post-stage hybrid coupler is used to output a reflected signal that is responsive to the output impedance of the post-stage hybrid coupler. The rectifying unit outputs a direct current using a reflected signal.

In some embodiments, the rectifying unit is electrically coupled to the power terminal of the first power amplifier and to the power terminal of the second power amplifier. The rectifying unit outputs a direct current to the power supply end of the two power amplifiers by using the reflected signal.

In some embodiments, the power amplification circuit further includes a pre-stage hybrid coupler. The pre-stage hybrid coupler is electrically connected to the input end of the first power amplifier and the input end of the second power amplifier to receive an input signal and generate the first signal and the second signal according to the input signal.

In some embodiments, the power amplifying circuit further includes a power detecting unit and a control unit. The power detecting unit is configured to detect the power of the reflected signal output from the isolated end. The control unit is electrically connected between the power detecting unit and the impedance matching unit to adjust the impedance value of the impedance matching unit according to the detection result of the power detecting unit.

According to the power amplifying circuit of the present invention, the direct current converted by the redundant reflected signal can be recovered to improve the efficiency of the power amplifying circuit or to improve the efficiency of the entire circuit including the power amplifying circuit. Moreover, according to the power of the reflected signal, the impedance of the impedance matching unit is dynamically adjusted to improve the RF-DC conversion efficiency, thereby further improving the efficiency of the power amplifying circuit.

Fig. 2 is a circuit block diagram of a power amplifying circuit 100 according to a first embodiment of the present invention.

Referring to FIG. 2, the power amplifier circuit 100 for improving efficiency includes a first power amplifier 210, a second power amplifier 220, a post-stage hybrid coupler 300, an impedance matching unit 400, and a rectifying unit 500.

The first power amplifier 210 has an input and an output. The second power amplifier 220 has an input and an output. The post-stage hybrid coupler 300 includes a first input port 310, a second input port 320, an output port 330, and an isolated port 340.

The first input 310 is electrically coupled to the output of the first power amplifier 210. The second input 320 is electrically coupled to the output of the second power amplifier 220. The impedance matching unit 400 is electrically connected between the isolated end 340 of the post-stage hybrid coupler 300 and the rectifying unit 500. The rectifying unit 500 is electrically connected to the power terminal 211 of the first power amplifier 210 and the power terminal 221 of the second power amplifier 220.

The input end of the first power amplifier 210 receives the first signal 901, and after being amplified by the first power amplifier 210, the amplified first signal 901 is outputted by the output end of the first power amplifier 210.

The input end of the second power amplifier 220 receives the second signal 902, and after being amplified by the second power amplifier 220, the amplified second signal 902 is outputted by the output end of the second power amplifier 220.

The second signal 902 has a phase difference from the first signal 901.

The output 330 of the post-stage hybrid coupler 300 is configured to output an output corresponding to the output of the first power amplifier 210 (ie, the amplified first signal 901) and the output of the second power amplifier 220 (ie, the amplified second signal) Output signal 903 of 902).

The isolated end 340 of the post-stage hybrid coupler 300 is configured to output a reflected signal 904 that is responsive to the output impedance of the post-stage hybrid coupler 300. In other words, the reflected signal 904 is derived from the impedance of the post-stage hybrid coupler 300 that does not exactly match the impedance between the loads connected to the output 330. The reflection signal 904 is directed to the output of the isolation terminal 340 by the post-stage hybrid coupler 300 to prevent the reflection signal 904 from affecting the stability and linearity of the first power amplifier 210 and the second power amplifier 220.

The impedance matching unit 400 is located between the isolated end 340 of the post-stage hybrid coupler 300 and the rectifying unit 500. When the reflected signal 904 is transmitted from the isolated end 340 to the rectifying unit 500, the power loss can be minimized.

The rectifying unit 500 outputs a direct current 905 using the reflected signal 904. Moreover, the output DC power 905 can be supplied to the power terminal 211 of the first power amplifier 210 and the power terminal 221 of the second power amplifier 220. Thereby, the power of the reflected signal 904 can be recovered to the first power amplifier 210 and the second power amplifier 220.

In some embodiments, the rectifying unit 500 can also be electrically connected to the power terminal of the circuit component outside the power amplifying circuit 100, thereby supplying the output DC 905 to an external circuit component for operation. Furthermore, the direct current 905 output by the rectifying unit 500 can be recovered into an electrical energy storage medium such as a capacitor or a battery for reuse.

In some embodiments, between the power terminal 211 of the first power amplifier 210 and the rectifying unit 500, and between the power terminal 221 of the second power amplifier 220 and the rectifying unit 500, a battery or a voltage regulator (Voltage regulator) is further provided. ) and other power supplies. Therefore, when the rectifying unit 500 outputs the direct current 905 to the power terminal 211 of the first power amplifier 210 and the power terminal 221 of the second power amplifier 220, the output current of the power source can be reduced, so that the efficiency of the overall power amplifying circuit 100 can be Get promoted.

In some embodiments, the rectifying unit 500 can be implemented by a radio frequency-to-direct current (RF-DC rectifier) to convert the reflected signal 904 into a direct current 905.

In some embodiments, the post hybrid coupler 300 can be a 90 degree hybrid coupler such as a Lange coupler or a 90 degree Wilkinson coupler with a 90 degree phase jog. Degree hybrid coupler). Moreover, the first signal 901 and the second signal 902 have equal amplitudes, but the phases are different by 90 degrees. Therefore, the post-stage hybrid coupler 300 can combine the first signal 901 and the second signal 902 as the output signal 903.

In some embodiments, the first power amplifier 210 and the second power amplifier 220 have the same gain, that is, have the same signal amplification.

Fig. 3 is a circuit block diagram of a power amplifying circuit 100 according to a second embodiment of the present invention.

Referring to FIG. 3, the power amplifier circuit 100 further includes a DC-DC converter 700.

The DC voltage converter 700 is electrically connected between the rectifying unit 500 and the power terminal 211 of the first power amplifier 210, and is electrically connected between the rectifying unit 500 and the power terminal 221 of the second power amplifier 220. Thereby, the voltage of the direct current 905 is adjusted to meet the voltage level of the power terminal 211 of the first power amplifier 210 and the power terminal 221 of the second power amplifier 220.

Fig. 4 is a circuit block diagram of a power amplifying circuit 100 according to a third embodiment of the present invention.

Referring to FIG. 4, the power amplifying circuit 100 further includes a pre-stage hybrid coupler 600. The pre-stage hybrid coupler 600 includes an input port 610, a transmitted port 620, a coupled port 630, and an isolated port 640. Thereby, the pre-stage hybrid coupler 600, the first power amplifier 210, the second power amplifier 220, and the post-stage hybrid coupler 300 can form a balanced power amplifier.

The input terminal 610 is configured to receive an input signal 900. The transmitting end 620 is electrically connected to the input end of the first power amplifier 210 to output the first signal 901. The coupling end 630 is electrically connected to the input end of the second power amplifier 220 to output the second signal 902. The isolated end 640 is configured to output a reflected signal 906 corresponding to the impedance that is not completely matched between the pre-stage hybrid coupler 600 and the first power amplifier 210 and the second power amplifier 220.

In some embodiments, the isolated end 640 of the pre-stage hybrid coupler 600 is electrically coupled to the grounded resistor 650 to dissipate the power of the reflected signal 906.

In some embodiments, the pre-stage hybrid coupler 600 can be a 90 degree hybrid coupler such as a Lange coupler or a 90 degree Wilkinson coupler with a 90 degree phase jog. ° hybrid coupler). Thereby, the input signal 900 is divided into a first signal 901 and a second signal 902 having the same amplitude and 90 degrees out of phase.

Fig. 5 is a circuit diagram of the impedance matching unit 400 and the rectifying unit 500 according to the first to third embodiments of the present invention.

Referring to FIG. 5 , the impedance matching unit 400 includes an inductor 401 and a capacitor 402 . One end of the inductor 401 is electrically connected to the isolated end 340 of the rear stage hybrid coupler 300, and the other end is electrically connected to the rectifying unit 500. One end of the capacitor 402 is electrically connected between the inductor 401 and the rectifying unit 500, and the other end is grounded. The conjugate matching is achieved by designing the inductance value of the inductor 401 and the capacitance value of the capacitor 402 so that the rectifying unit 500 can have an optimum RF-DC conversion efficiency.

As shown in FIG. 5, the rectifying unit 500 includes a first capacitor 501, a second capacitor 502, a first diode 503, and a second diode 504. One end of the first capacitor 501 is electrically connected to the impedance matching unit 400. One end of the first diode 503 is electrically connected to the other end of the first capacitor 501, and the other end of the first diode 503 is electrically connected to the power terminal 211 of the first power amplifier 210 and the power terminal 221 of the second power amplifier 220. One end of the second diode 504 is electrically connected between the first capacitor 501 and the first diode 503, and the other end of the second diode 504 is grounded. One end of the second capacitor 502 is grounded, and the other end is electrically connected to the power terminal 211 of the first power amplifier 210 and the power terminal 221 of the second power amplifier 220. Thereby, the reflected signal 904 charges the first capacitor 501 and the second capacitor 502 via the impedance matching unit 400, so that the second capacitor 502 generates a direct current 905 when discharging.

Fig. 6 is a diagram showing the RF-DC conversion efficiency of the rectifying unit 500 according to the third embodiment of the present invention.

Referring to FIG. 5 and FIG. 6 , when the inductance 401 of the impedance matching unit 400 is 5.6 nano Henry (nH), the capacitance is 15 pico Farad (pF), and the first capacitor 501 of the rectifying unit 500 When it is 32 picofarads (pF) and the second capacitor 502 is 1 microfarad (μF), the RF-DC conversion efficiency of the rectifying unit 500 is as shown in FIG.

Here, the values of the circuits of the impedance matching unit 400 and the rectifying unit 500 and the internal components thereof shown in FIG. 5 are merely examples, and the first to third embodiments of the present invention are not limited thereto.

Fig. 7 is a comparison diagram (1) of the efficiency of power recovery according to the third embodiment of the present invention. Fig. 8 is a comparison diagram (2) of the efficiency of power recovery according to the third embodiment of the present invention.

As shown in FIG. 7, the power amplifying circuit 100 (with power recovery) of the third embodiment and the impedance matching unit 400 and the rectifying unit 500 in the power amplifying circuit 100 are compared when the voltage standing wave ratio is 2:1. The efficiency of both the power amplifying circuit 100 (without power recovery) of the third embodiment of the recovery path. Figure 7 also shows the efficiency improvement of power recovery relative to no power recovery.

As shown in FIG. 8, the power matching circuit 100 (with power recovery) of the third embodiment and the impedance matching unit 400 and the rectifying unit 500 in the power amplifying circuit 100 are compared when the voltage standing wave ratio is 4:1. The efficiency of both the power amplifying circuit 100 (without power recovery) of the third embodiment of the recovery path. Figure 8 also shows the efficiency of power recovery versus no-power recovery.

Referring to FIG. 6, the RF-DC conversion efficiency diagram of the rectifying unit 500 shown in FIG. 6 shows that the input impedance and the RF-DC conversion efficiency of the rectifying unit 500 vary depending on the power of the reflected signal 906. Therefore, it is necessary to make the rectifying unit 500 have the maximum RF-DC conversion efficiency by adjusting the impedance value of the impedance matching unit 400.

Fig. 9 is a circuit block diagram (1) of the power amplifying circuit 100 according to the fourth embodiment of the present invention.

Referring to FIG. 9 , the power amplifying circuit 100 further includes a power detecting unit 810 and a control unit 820 . The control unit 820 is electrically connected between the power detecting unit 810 and the impedance matching unit 400.

The power detecting unit 810 is configured to detect the power of the reflected signal 904 output by the isolated end 340 of the hybrid mixer 300. The control unit 820 is configured to adjust the impedance value of the impedance matching unit 400 according to the detection result of the power detecting unit 810.

Fig. 10 is a circuit block diagram (2) of the power amplifying circuit 100 according to the fourth embodiment of the present invention.

As shown in FIG. 10, in some embodiments, the power amplifying circuit 100 further includes a coupling unit 830 electrically connected to the power detecting unit 810 and the isolated terminal 340. The coupling unit 830 is configured to couple a portion of the reflected signal 904 to the power detecting unit 810.

In some embodiments, the coupling unit 830 can be implemented by a direction coupler and electrically connected to the isolation terminal 340, the impedance matching unit 400, and the power measurement unit 810. The directional coupler can split the reflected signal 904 into two parts, a few parts branch to the power measuring unit 810, and the remaining part continues to be transmitted to the impedance matching unit 400. Therefore, the power detecting unit 810 can further convert the detected power into the power of the overall reflected signal 904 by detecting the power of the portion of the reflected signal 904.

Figure 11 is a schematic diagram of an impedance matching unit 400 in accordance with a fourth embodiment of the present invention. Figure 12 is a circuit diagram of an impedance matching unit 400 and a rectifying unit 500 according to a fourth embodiment of the present invention.

As shown in FIG. 11, the impedance matching unit 400 may include the variable impedance element 430, and the control unit 820 adjusts the impedance value of the variable impedance element 430 to determine the impedance value of the impedance matching unit 400. The varactor element 430 is electrically connected to the isolation terminal 340 and the rectifying unit 500. However, the fourth embodiment of the present invention does not limit the varactor element 430 to electrically connect the isolation terminal 340 and the rectifying unit 500 in series.

Refer to Figure 11 and Figure 12 for the merger. In some embodiments, the variable impedance element 430 can be a variable capacitor 434. As shown in FIG. 12, the variable capacitor 434 is electrically connected between the isolated terminal 340 of the post-stage hybrid coupler 300 and the rectifying unit 500. Thereby, the control unit 820 can determine the impedance value of the impedance matching unit 400 by adjusting the capacitance value of the variable capacitor 434.

In some embodiments, the varactor element 430 can be electrically coupled to the isolated end 340 of the post-stage hybrid coupler 300 via the coupling unit 830 as shown in FIG.

In some embodiments, the variable impedance element 430 can also be implemented with a variable inductance or a Reactance modulator.

FIG. 12 is another circuit diagram of the impedance matching unit 400 and the rectifying unit 500. The impedance matching unit 400 includes a capacitor 432 and a variable capacitor 434 connected in series, electrically connected between the isolation terminal 340 and the rectifying unit 500, and two inductive inductors 431, 433. The inductor 431 is electrically connected between the capacitor 432 and the variable capacitor 434, and the inductor 433 is electrically connected between the variable capacitor 434 and the rectifying unit 500.

In some embodiments, the variable capacitor 434 can be implemented as a variable capacitance diode. The capacitance value of the variable capacitor 434 is adjusted by the control unit 820 according to the power of the reflected signal 904. In other words, the control unit 820 can control the power of the partial reflection signal 904 or the power of the corresponding overall reflection signal 904 according to the power detection unit 810, and control the reverse bias applied to the varactor. The capacitance value of the variable capacitor 434.

Figure 13 is a Smith chart of the impedance matching unit 400 according to the fourth embodiment of the present invention.

Referring to Figures 10, 12 and 13, when the capacitance 432 of the impedance matching unit 400 is 32 picofarads (pF), the capacitance value of the variable capacitor may include 7 picofarads (pF), and the inductance 431 is 17 nai Henry ( nH), the inductance 433 is 24 Nai Henry (nH), and the first capacitor 501 of the rectifying unit 500 is 32 picofarads (pF), and the second capacitor 502 is 1 microfarad (μF), the impedance matching unit 400 The input impedance is shown in Figure 13. When the capacitance value of the variable capacitor 434 is increased, the impedance of the impedance matching unit 400 moves in the direction of the arrow.

Here, the values of the circuits of the impedance matching unit 400 and the rectifying unit 500 and the internal components thereof shown in FIG. 12 are merely examples, and the fourth embodiment of the present invention is not limited thereto.

In summary, according to the power amplifying circuit 100 of the present invention, the direct current 905 converted by the redundant reflected signal 904 can be recovered to improve the efficiency of the power amplifying circuit 100 or to improve the overall power amplifier circuit 100. The efficiency of the circuit. Moreover, the impedance of the impedance matching unit 400 is dynamically adjusted according to the power of the reflected signal 904 to improve the RF-DC conversion efficiency, thereby further improving the efficiency of the power amplifying circuit 100.

While the present invention has been described above in the foregoing embodiments, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of patent protection shall be subject to the definition of the scope of the patent application attached to this specification.

100. . . Power amplifier circuit

210. . . First power amplifier

211. . . Power terminal

220. . . Second power amplifier

221. . . Power terminal

300. . . Rear hybrid coupler

310. . . First input

320. . . Second input

330. . . Output

340. . . Isolated end

400. . . Impedance matching unit

401. . . inductance

402. . . capacitance

430. . . Variable reactance component

431. . . inductance

432. . . capacitance

433. . . inductance

434. . . Variable capacitance

500. . . Rectifier unit

501. . . First capacitor

502. . . Second capacitor

503. . . First diode

504. . . Second diode

600. . . Pre-stage hybrid coupler

610. . . Input

620. . . Transmission end

630. . . Coupling end

640. . . Isolated end

650. . . resistance

700. . . DC voltage converter

810. . . Power detection unit

820. . . control unit

830. . . Coupling unit

900. . . Input signal

901. . . First signal

902. . . Second signal

903. . . Output signal

904. . . Reflection signal

905. . . Direct current

906. . . Reflection signal

PA. . . Power amplifier

P _dc . . . DC power

P _in. . . input power

P _out . . . Output Power

Figure 1 is a schematic diagram of a general power amplifier;

2 is a circuit block diagram of a power amplifying circuit according to a first embodiment of the present invention;

Figure 3 is a circuit block diagram of a power amplifying circuit according to a second embodiment of the present invention;

Figure 4 is a circuit block diagram of a power amplifying circuit according to a third embodiment of the present invention;

Figure 5 is a circuit diagram of an impedance matching unit and a rectifying unit according to the first to third embodiments of the present invention;

Figure 6 is a diagram showing the RF-DC conversion efficiency of the rectifying unit according to the third embodiment of the present invention;

Figure 7 is a comparison diagram of the efficiency of power recovery according to the third embodiment of the present invention (1);

Figure 8 is a comparison diagram of the efficiency of power recovery according to the third embodiment of the present invention (2);

Figure 9 is a circuit block diagram (1) of a power amplifying circuit according to a fourth embodiment of the present invention;

Figure 10 is a circuit block diagram (2) of a power amplifying circuit according to a fourth embodiment of the present invention;

Figure 11 is a schematic diagram of an impedance matching unit according to a fourth embodiment of the present invention;

Figure 12 is a circuit diagram of an impedance matching unit and a rectifying unit according to a fourth embodiment of the present invention;

Figure 13 is a Smith chart of an impedance matching unit according to a fourth embodiment of the present invention.

100. . . Power amplifier circuit

210. . . First power amplifier

211. . . Power terminal

220. . . Second power amplifier

221. . . Power terminal

300. . . Rear hybrid coupler

310. . . First input

320. . . Second input

330. . . Output

340. . . Isolated end

400. . . Impedance matching unit

500. . . Rectifier unit

901. . . First signal

902. . . Second signal

903. . . Output signal

904. . . Reflection signal

905. . . Direct current

Claims (9)

A power amplifier circuit for improving efficiency includes: a first power amplifier having an input terminal for receiving a first signal; and a second power amplifier having an input terminal for receiving a second signal, wherein the second a phase difference between the signal and the first signal; a post-stage hybrid coupler comprising: a first input terminal electrically connected to the output end of the first power amplifier; and a second input terminal electrically connected to the second An output end of the power amplifier; an output end for outputting an output signal corresponding to an output of the first power amplifier and an output of the second power amplifier; and an isolation end responsive to the rear stage hybrid coupler The output impedance outputs a reflection signal; an impedance matching unit electrically connects the isolation end of the post-stage hybrid coupler; and a rectifying unit electrically connected to the impedance matching unit to continuously galvanically output the reflected signal. The power amplifying circuit of claim 1, wherein the rectifying unit is electrically connected to a power terminal of the first power amplifier, and is electrically connected to a power terminal of the second power amplifier, and outputs the DC power to the two power terminals. The power amplifying circuit of claim 1, further comprising: a DC voltage converter electrically connected to the rectifying unit to adjust the voltage of the direct current. The power amplifier circuit of claim 1, wherein the rectifying unit comprises: a first capacitor, one end of which is electrically connected to the impedance matching unit; and a first diode, one end of which is electrically connected to the other end of the first capacitor, and the other end Electrically connecting the power terminal of the first power amplifier and the power terminal of the second power amplifier; a second diode having one end electrically connected between the first capacitor and the first diode, and the other end grounded; The second capacitor is grounded at one end, and the other end is electrically connected to the power terminal of the first power amplifier and the power terminal of the second power amplifier. The power amplifying circuit of claim 1, further comprising: a pre-stage hybrid coupler electrically connected to the input end of the first power amplifier and the input end of the second power amplifier to receive an input signal and according to The input signal generates the first signal and the second signal. The power amplifier circuit of claim 1, further comprising: a power detecting unit configured to detect the power of the reflected signal output by the isolated end; and a control unit electrically connected to the power detecting unit and the The impedance matching unit adjusts the impedance value of the impedance matching unit according to the detection result of the power detecting unit. The power amplifying circuit of claim 6, further comprising: a coupling unit electrically connected to the power detecting unit and the isolating end for coupling a part of the reflected signal to the power detecting unit for the The power detecting unit detects the power of the reflected signal. The power amplifying circuit of claim 6, wherein the impedance matching unit comprises: a variable impedance component, wherein the control unit determines the impedance value of the impedance matching unit by adjusting an impedance value of the variable impedance component. The power amplifier circuit of claim 8, wherein the variable impedance component is a variable capacitor, wherein the control unit determines the impedance value of the impedance matching unit by adjusting a capacitance value of the variable capacitor.