Radio-frequency power supply, radio-frequency amplifier and method for improving efficiency of radio-frequency amplifier

• US 10,111,187 B2
• Filed: 08/17/2017
• Issued: 10/23/2018
• Est. Priority Date: 12/13/2016
• Status: Active Grant

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Lai, Wei-Hsun, Hsu, Chi
• Primary Examiner(s): Lee, John J
• Application Number:
  US15/679,810
• Publication Number:
  US 20180167898A1
• Time in Patent Office: 432 Days
• Field of Search: 4551942, 4551931, 455311, 455341
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 1/0222 by using a signal derived from the input signal
• CPC Class Codes: H03F 1/0233 by using a signal derived from the output signal, e.g. bootstrapping the voltage supply
• CPC Class Codes: H03F 1/30 Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in differential amplifiers H03F3/45479
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03G 3/3036 in high-frequency amplifiers or in frequency-changers H03G3/3052, H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for improving an efficiency of a radio-frequency amplifier includes following steps. A set of predetermined parameters are set. A total circuit parameter is calculated according to the set of the predetermined parameters. A switch stress of a power switch is calculated according to the set of the predetermined parameters and the total circuit parameter. A first curve graph is made according to a duty cycle corresponding to the switch stress. The efficiency is calculated according to the set of the predetermined parameters and the total circuit parameter. A second curve graph is made according to the duty cycle corresponding to the efficiency of the radio-frequency amplifier. A value of the duty cycle is selected according to the first curve graph. The efficiency corresponding to the value of the duty cycle is obtained according to the second curve graph.

Claims

1. A method for improving an efficiency of a radio-frequency amplifier, the radio-frequency amplifier comprising an input loop and an output loop, the input loop comprising an input inductor and a power switch, the input inductor connected to the power switch in series, the output loop comprising an output capacitor and a resonant unit, the output capacitor connected to the resonant unit in series, the power switch connected to the output capacitor in parallel and converting an input voltage into an output voltage, the method comprising:

(a) setting a set of predetermined parameters, wherein the set of the predetermined parameters comprises an output power of the radio-frequency amplifier, the input voltage, an operation frequency and a duty cycle;

(b) calculating a total circuit parameter according to the set of the predetermined parameters;

(c) calculating a switch stress of the power switch according to the set of the predetermined parameters and the calculated total circuit parameter;

(d) calculating the efficiency of the radio-frequency amplifier according to the set of the predetermined parameters and the calculated total circuit parameter; and

(e) checking whether the efficiency of the radio-frequency amplifier is within a predetermined range or not, wherein if the efficiency of the radio-frequency amplifier is not within the predetermined range, the input voltage or the duty cycle of the set of the predetermined parameters is adjusted, and then the method returns to the step (a);

if the efficiency of the radio-frequency amplifier is within the predetermined range, a value of the duty cycle is selected as a duty cycle of the power switch of the radio-frequency amplifier.

2. The method in claim 1, wherein the step (c) further comprises:

(c1) making a first curve graph according to the duty cycle corresponding to the switch stress.

3. The method in claim 2, wherein the step (d) further comprises:

(d1) making a second curve graph according to the duty cycle corresponding to the efficiency of the radio-frequency amplifier.

4. The method in claim 3 further comprising after the step (d1):

(d2) selecting the value of the duty cycle according to the first curve graph;

obtaining the efficiency of the radio-frequency amplifier corresponding to the value of the duty cycle according to the second curve graph.

5. The method in claim 1, wherein the step (e) further comprises:

(e1) checking whether a total harmonic distortion and a cooling capacity of the radio-frequency amplifier are within the predetermined range or not, wherein if the total harmonic distortion or the cooling capacity of the radio-frequency amplifier is not within the predetermined range, the input voltage or the duty cycle of the set of the predetermined parameters is adjusted, and then the method returns to the step (a);

if the total harmonic distortion and the cooling capacity of the radio-frequency amplifier are within the predetermined range, the value of the duty cycle is selected as the duty cycle of the power switch of the radio-frequency amplifier.

6. The method in claim 1, wherein the calculated total circuit parameter comprises a phase-shift angle of the radio-frequency amplifier, an electric capacity of the output capacitor, an input current of the radio-frequency amplifier and a resonant current of the resonant unit.

7. The method in claim 1, wherein the step (d) further comprises:

(d2) calculating a total power loss of the radio-frequency amplifier according to the set of the predetermined parameters and the calculated total circuit parameter;

calculating the efficiency of the radio-frequency amplifier according to the total power loss, wherein the efficiency of the radio-frequency amplifier is equal to a ration of a power output of the radio-frequency amplifier relative to an overall power consumption of the radio-frequency amplifier.

8. The method in claim 7, wherein the resonant unit comprises a resonant capacitor and a resonant inductor;

the resonant capacitor is connected to the resonant inductor in series;

the step (d) further comprises;

(d3) selecting an inductance of the input inductor, a capacitance of the resonant capacitor and an inductance of the resonant inductor according to the total power loss.

9. The method in claim 1, wherein the switch stress comprises a switch voltage stress and a switch current stress.

10. The method in claim 9, wherein the step (c) further comprises:

(c2) selecting the power switch according to the switch voltage stress and the switch current stress.

11. The method in claim 1, wherein the total power loss comprises a power loss of the power switch, a power loss of the output capacitor, a power loss of the resonant unit and a power loss of the input inductor.

12. A radio-frequency amplifier comprising:

an input loop comprising an input inductor and a power switch, the input inductor connected to the power switch in series and receiving an input voltage; and

an output loop comprising an output capacitor and a resonant unit, the output capacitor connected to the power switch in parallel, the resonant unit connected to the output capacitor in series and outputting an output voltage,

wherein a duty cycle of the power switch of the radio-frequency amplifier is determined by the method in claim 1.

13. The radio-frequency amplifier in claim 12, wherein the input voltage of the radio-frequency amplifier is the input voltage corresponding to the duty cycle of the power switch.

14. A radio-frequency power supply comprising:

a power factor correction unit converting an alternating current input voltage into a direct current voltage;

a converting unit connected to the power factor correction unit and converting the direct current voltage into an input voltage;

a radio-frequency amplifier connected to the converting unit and converting the input voltage into an output voltage; and

a control unit controlling the power factor correction unit, the converting unit and the radio-frequency amplifier,

wherein the radio-frequency amplifier comprises an input loop and an output loop;

the input loop comprises an input inductor and a power switch;

the input inductor is connected to the power switch in series;

the output loop comprises an output capacitor and a resonant unit;

the output capacitor is connected to the resonant unit in series;

the power switch is connected to the output capacitor in parallel;

a duty cycle of the power switch of the radio-frequency amplifier is determined by the method in claim 1.

15. The radio-frequency power supply in claim 14, wherein the input voltage of the radio-frequency amplifier is the input voltage corresponding to the duty cycle of the power switch.

16. The radio-frequency power supply in claim 15, wherein a voltage conversion ratio of the converting unit is adjusted according to the input voltage.