Power supply modulation method and power supply modulator

• US 9,154,029 B2
• Filed: 10/24/2011
• Issued: 10/06/2015
• Est. Priority Date: 03/17/2011
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Wang, Linguo, Zhang, Bin
• Primary Examiner(s): GBLENDE, JEFFREY A
• Application Number:
  US14/005,543
• Publication Number:
  US 20140002053A1
• Time in Patent Office: 1,443 Days
• Field of Search: 323/234, 323/237, 323/265, 323273-275, 323282-284, 323/299, 323/300, 323/303, 363 65- 72
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 3/10 using discharge tubes with control electrode or semiconductor devices with control electrode H02M3/07 takes precedence
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 3/1566 with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• CPC Class Codes: H03F 1/0227 using supply converters

Abstract

A modulation method and modulator for an envelope tracking power supply. An output of a multi-level switching regulator (202) in the envelope tracking power supply modulator is in parallel connection with an output of a linear regulator (201) via an inductor (203) and supplies power to a load. The modulation method for the envelope tracking power supply includes: generating a first control signal (209) according to the current (211) obtained from inputting a first reference level signal (206); comparing the amplitude of a second reference level signal (2061) obtained according to the first reference level signal (206) with preset amplitudes of at least three levels, and outputting a second control signal (210) according to the comparison result and the first control signal (209); the multi-level switching regulator (202) outputting a level signal of corresponding amplitude according to the second control signal (210), and loading the amplitude of the level on the inductor (203) to output an inductive current (208′); and linearly regulating the first reference level signal (206) via a linear regulator (201) to obtain a voltage output (207) to the load. The present disclosure resolves the problem of fixed rate of change of current output by the switching regulator of the envelope tracking power supply regulator and cannot adjust to different load current change rates, thus the inductive current outputted by the multi-level switching regulator can better track the load current change.

Claims

1. A modulation method for an envelope tracking power supply, wherein an output of a multi-level switch regulator in the envelope tracking power supply is connected in parallel with an output of a linear regulator through an inductor, the method comprising:

generating a first control signal according to a current obtained from an input first reference level signal, wherein the first reference level signal controls a change trend of an output current of the multi-level switch regulator;

comparing an amplitude of a second reference level signal obtained from the first reference level signal with preset amplitudes of at least three grades of levels, outputting a second control signal according to a result of the comparison and the first control signal, wherein at least one of the preset amplitudes of at least three grades of levels is less than the amplitude of the second reference level signal and at least one of the preset amplitudes of at least three grades of levels is greater than the amplitude of the second reference level signal;

outputting, by the multi-level switch regulator, a level signal with a corresponding amplitude according to the second control signal, and applying the level signal with the corresponding amplitude on the inductor to output an inductive current; and

linearly adjusting, by the linear regulator, the first reference level signal to obtain a voltage output from the envelope tracking power supply to a load.

2. The method according to claim 1, wherein outputting the second control signal according to the result of the comparison and the first control signal comprises:

outputting the second control signal that instructs the multi-level switch regulator to output a level signal with an amplitude higher than that of a reference level signal, when the first control signal requires that the inductive current output from the multi-level switch regulator becomes larger; and

outputting the second control signal that instructs the multi-level switch regulator to output a level signal with an amplitude lower than that of the reference level signal, when the first control signal requires that the inductive current output from the multi-level switch regulator becomes smaller.

3. The method according to claim 1, wherein comparing the amplitude of the second reference level signal obtained from the first reference level signal with preset amplitudes of at least three grades of levels comprises:

taking an amplitude of the first reference level signal as the amplitude of the second reference level signal, and comparing the amplitude of the first reference level signal with the preset amplitudes of at least three grades of levels.

4. The method according to claim 1, wherein comparing the amplitude of the second reference level signal obtained from the first reference level signal with preset amplitudes of at least three grades of levels comprises:

taking an amplitude of a signal obtained through linearly adjusting the first reference signal as the amplitude of the second reference level signal, and comparing the amplitude of the signal obtained through linearly adjusting the first reference signal with the preset amplitudes of at least three grades of levels, wherein the preset amplitudes of respective grades of levels are equal to amplitudes of respective grades of levels output from the multi-level switch regulator.

5. The method according to claim 1, wherein generating the first control signal according to the current obtained from the input first reference level signal comprises:

generating the first control signal that controls the multi-level switch regulator to increase the inductive current output from the multi-level switch regulator, when the current obtained from the input first reference level signal is greater than an upper limit threshold; and

generating the first control signal that controls the multi-level switch regulator to reduce the inductive current output from the multi-level switch regulator, when the current obtained from the input first reference level signal is less than a lower limit threshold.

6. The method according to claim 5, wherein, the current obtained from the input first reference level signal is a linearly adjusted output current, or a linearly adjusted output current estimation obtained according to the first reference level signal and circuit parameters of the power supply.

7. The method according to claim 6, further comprising, after obtaining the linearly adjusted output current estimation according to the first reference level signal and circuit parameters of the power supply, of:

estimating a load current slope according to the first reference level signal and circuit parameters of the power supply to obtain a predicted signal of a load current change rate, and performing slope compensation control on the predicted signal of the load current change rate to obtain a slope compensation control signal;

wherein outputting the second control signal according to the result of the comparison and the first control signal comprises;

outputting the second control signal according to the result of the comparison, the first control signal and the slope compensation control signal.

8. The method according to claim 6, wherein linearly adjusting, by the linear regulator, the first reference level signal to obtain the voltage output from the power supply to the load comprises:

performing high-pass filtering on an output voltage after linearly adjusting the first reference level signal by the linear regulator; and

using the filtered output voltage as the voltage output from the power supply to the load.

9. The method according to claim 6, wherein outputting, by the multi-level switch regulator, the level signal with the corresponding amplitude and applying a level signal with the corresponding amplitude on the inductor to output the inductive current comprises:

performing low-pass filtering on a sampled current signal output after linearly adjusting; and

using the filtered sampled current signal to control the inductive current output from the multi-level switch regulator.

10. A modulator for an envelope tracking power supply, comprising a linear regulator, a multi-level switch regulator, an inductor, a current controller and a level selection controller, wherein, an output of the multi-level switch regulator is connected in parallel with an output of the linear regulator through the inductor;

the current controller, the level selection controller and the multi-level switch regulator are connected in series;

the current controller is configured to generate a first control signal according to a current obtained from an input first reference level signal, wherein the first reference level signal controls a change trend of an output current of the multi-level switch regulator, the current controller is connected with the level selection controller through a port for outputting the first control signal, and a second reference level signal obtained from the first reference level signal is input to the level selection controller;

the level selection controller is configured to compare an amplitude of the second reference level signal obtained from the first reference level signal with preset amplitudes of at least three grades of levels to output a second control signal, wherein at least one of the preset amplitudes of at least three grades of levels is less than the amplitude of the second reference level signal, and at least one of the preset amplitudes of at least three grades of levels is greater than the amplitude of the second reference level signal, the level selection controller is connected with the multi-level switch regulator through a port for outputting the second control signal;

the multi-level switch regulator is configured to output a level signal with a corresponding amplitude according to the second control signal, and to apply a level signal with the corresponding amplitude on the inductor to output an inductive current; and

the linear regulator is configured to linearly adjust the first reference level signal to obtain a voltage output from the envelope tracking power supply to a load.

11. The modulator according to claim 10, wherein the level selection controller is further configured to:

output the second control signal that instructs the multi-level switch regulator to output a level signal with an amplitude higher than that of a reference level signal, when the first control signal requires that the inductive current output from the multi-level switch regulator becomes larger; and

output the second control signal that instruct the multi-level switch regulator to output a level signal with an amplitude lower than that of the reference level signal, when the first control signal requires that the inductive current output from the multi-level switch regulator becomes smaller.

12. The modulator according to claim 10, wherein the first reference level signal is input to an input for the second reference signal of the level selection controller, and wherein the level selection controller is further configured to compare an amplitude of the first reference level signal with preset amplitudes of at least three grades of levels.

13. The modulator according to claim 10, wherein, an input for the second reference signal of the level selection controller is configured to input a signal obtained through linearly adjusting the first reference signal, the level selection controller is further configured to compare an amplitude of the signal obtained through linearly adjusting the first reference signal with preset amplitudes of at least three grades of levels, wherein, the preset amplitudes of respective grades of levels are equal to amplitudes of respective grades of levels output from the multi-level switch regulator.

14. The modulator according to claim 10, wherein, the current controller is further configured to:

generate the first control signal that controls the multi-level switch regulator to increase the output inductive current, when the current obtained from the input first reference level signal is greater than an upper limit threshold; and

generate the first control signal that controls the multi-level switch regulator to reduce the output inductive current, when the current obtained from the input first reference level signal is less than a lower limit threshold.

15. The modulator according to claim 14, wherein an input of the current controller for the current obtained according to the first reference level signal is configured to input a sampled linearly adjusted output current;

or the modulator further comprising an estimator configured to obtain a linearly adjusted output current estimation according to the first reference level signal and circuit parameters of the power supply, wherein a port of the estimator for outputting the current estimation is connected to the input of the current controller for the current obtained according to the first reference level signal.

16. The power supply modulator according to claim 15, wherein the first reference level signal is input to a load current slope estimation circuit configured to estimate a load current slope according to the first reference level signal and circuit parameters of the envelope tracking power supply to output a predicted signal of a load current change rate;

wherein a port for outputting the predicted signal of the load current change rate is connected to a slope compensation control circuit configured to perform slope compensation control on the predicted signal of the load current change rate to obtain a slope compensation control signal, wherein a port for outputting the slope compensation control signal is connected to the level selection controller configured to output the second control signal according to the result of the comparison, the first control signal and the slope compensation control signal.

17. The power supply modulator according to claim 15, wherein an output of the linear regulator is connected in series with a high-pass filter and further connected in parallel with the multi-level switch regulator through the inductor.

18. The modulator according to claim 15, wherein an output of the linear regulator is connected with a low-pass filter outputting a low-frequency signal of the sampled linearly adjusted output current signal, wherein a port of the low-pass filter for outputting the low-frequency signal of current is connected with the multi-level switch regulator, the multi-level switch regulator is further configured to control the output inductive current with the sampled linearly adjusted output current signal after low-pass filtering.