CN113141163B - Class D power amplifier circuit - Google Patents
Class D power amplifier circuit Download PDFInfo
- Publication number
- CN113141163B CN113141163B CN202010058159.4A CN202010058159A CN113141163B CN 113141163 B CN113141163 B CN 113141163B CN 202010058159 A CN202010058159 A CN 202010058159A CN 113141163 B CN113141163 B CN 113141163B
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- supply voltage
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- power supply
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- 230000000737 periodic effect Effects 0.000 claims abstract description 35
- 230000005236 sound signal Effects 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
- H03F1/12—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements by use of attenuating means
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
A class D power amplifier circuit includes an input stage, a periodic signal generator, a comparator, a power output stage, and a boost generator. The input stage is coupled to a first supply voltage. The periodic signal generator is used for generating a periodic signal and a reference signal. The power output stage is coupled to a second power supply voltage. The boost generator is used for comparing the output of the input stage with the reference signal so as to adjust the voltage value of the second power supply voltage. The voltage value of the second power supply voltage is larger than the voltage value of the first power supply voltage. The reference signal is proportional to the amplitude of the periodic signal, and the amplitude of the periodic signal is determined by the voltage value of the second power supply voltage.
Description
Technical Field
The invention relates to a class D power amplifier circuit.
Background
Fig. 1 shows a block diagram of a prior art class D power amplifier circuit 100. Referring to fig. 1, the power amplifier circuit 100 includes an input stage 10, a comparator 12, and a power output stage 14. The input stage 10 has an amplifier (not shown) coupled to a supply voltage VDD. The comparator 12 is used for comparing the output Vs of the input stage 10 with the periodic signal to generate a comparison signal cmp. The power output stage 14 is coupled to another power supply voltage PVDD, which is generated by a voltage boost circuit 16, wherein the voltage level of the power supply voltage PVDD is greater than the voltage level of the power supply voltage VDD.
IN order to maintain high efficiency, the conventional class D power amplifier circuit 100 uses the voltage detection circuit 18 to detect the amplitude of the input signal IN, so as to adjust the voltage level of the power supply voltage PVDD according to the amplitude of the input signal IN. However, this approach reduces the efficiency of the class D power amplifier circuit 100 when the input signal IN is low IN amplitude.
Disclosure of Invention
A class D power amplifier circuit according to one embodiment of the present invention includes an input stage, a periodic signal generator, a comparator, a power output stage, and a boost generator. The input stage is coupled to a first power supply voltage and is configured to receive an input voltage at a first node. The periodic signal generator is used for generating a periodic signal and a reference signal. The comparator is used for comparing the output of the input stage with the periodic signal so as to generate a first comparison result. The power output stage is coupled to the second power voltage, and is configured to receive the comparison result to generate a pulse modulation signal. The boost generator is used for comparing the output of the input stage with the reference signal so as to adjust the voltage value of the second power supply voltage. The voltage value of the second power supply voltage is larger than the voltage value of the first power supply voltage. The reference signal is proportional to the amplitude of the periodic signal, and the amplitude of the periodic signal is determined by the voltage value of the second power supply voltage.
Drawings
Fig. 1 shows a block diagram of a prior art class D power amplifier circuit.
Fig. 2 shows a block diagram of a class D power amplifier circuit incorporating an embodiment of the invention.
Fig. 3 shows a partial circuit schematic of the class D power amplifier circuit in combination with an embodiment of the invention.
Fig. 4 shows waveforms of the output signals of the periodic signal generator in an embodiment of the invention.
Detailed Description
Certain terms are used throughout the description and following claims to refer to particular components. It will be appreciated by those of ordinary skill in the art that manufacturers may refer to a component by different names. The present specification and the claims to follow do not take the form of an element differentiated by name, but rather by functional differences. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. In addition, the term "coupled" as used herein includes any direct or indirect electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
Fig. 2 shows a block diagram of a class D power amplifier circuit 200 incorporating an embodiment of the invention. Referring to fig. 2, the class D power amplifier circuit 200 includes an input stage 20, a comparison unit 22, a power output stage 24, a low frequency filter 25, a boost generator 26, and a periodic signal generator 27. The input stage 10 is coupled to a supply voltage VDD. The periodic signal generator 27 is used for generating a periodic signal Vp, such as a periodic triangular wave signal or a periodic saw-tooth wave signal. The comparing unit 22 is used for comparing the output Vs of the input stage 10 with the periodic signal Vp to generate a comparison result cmp. The power output stage 24 receives the comparison result cmp to generate the pulse modulation signal OUT. The low frequency filter 25 attenuates the high frequency component of the pulse modulated signal OUT. The filtered output VOUT is provided to a speaker (not depicted) to produce sound.
Referring to fig. 2, the power output stage 24 is coupled to another power supply voltage PVDD generated by the boost generator 26, wherein the voltage level of the power supply voltage PVDD is greater than the voltage level of the power supply voltage VDD. The power voltage PVDD is additionally transmitted to the periodic signal generator 27, thereby varying the amplitude of the periodic signal Vp.
Fig. 3 shows a partial circuit schematic of the class D power amplifier circuit 200' incorporating an embodiment of the invention. Referring to fig. 3, the input stage 20' includes a dual differential input, a dual differential output amplifier X1, resistors R1, R2, and capacitors C1, C2. The resistors R1, R2 receive first and second input signals INP and INN. The input signals INP and INN are a pair of differential audio signals in the present embodiment, but the invention is not limited thereto. In other embodiments, the amplifier X1 is a single-ended differential input, double-ended differential output amplifier.
The output signals Vs1, vs2 of the amplifier X1 are compared with the periodic signal Vp generated by the periodic signal generator 27 to generate comparison signals cmp1 and cmp2. In one embodiment, the comparison signals cmp1 and cmp2 are complementary signals. The comparison signals cmp1 and cmp2 are passed through the power output stage 24 to generate complementary pulse modulation signals OUTP and OUTN. In this embodiment, the feedback elements 28,28' are of a resistive type, which respectively feed back the pulse modulated signals OUTP and OUTN to the differential inputs of the amplifier X1.
Referring to fig. 3, the output signals Vs1, vs2 of the amplifier X1 are compared with a signal Va generated by the periodic signal generator 27, wherein the signal Va is proportional to the amplitude of the periodic signal Vp. Fig. 4 shows the relationship of signals Va and Vp in an embodiment of the invention. In this example, the periodic signal Vp is a triangular wave signal with an amplitude Vhl, wherein the amplitude is determined by the voltage level of the power supply voltage PVDD. The signal Va is a direct current signal whose voltage value is equal to α×vhl, where α is between 0 and 1.
Referring to fig. 3, the boost generator 26 includes two comparators 262,264, an n-bit counter 266, and a boost circuit 268. The comparators 262,264 are used to compare the output signals Vs1, vs2 of the amplifier X1 with the signal Va. In one embodiment, a low pass filter (not shown) is disposed between the output of the amplifier X1 and the inputs of the comparators 262,264 to filter noise from the output signals Vs1, vs2 of the amplifier X1. The N-bit counter 266 receives the comparison results of the comparators 262,264 to generate an N-bit output signal. The boost circuit 268 receives the N-bit output signal and generates the power supply voltage PVDD for providing to the power output stage 24. The boost circuit may be a direct current to direct current voltage converter (DC-DC voltage converter), or a charge pump (charge pump).
In operation, the N-bit counter 266 generates an output signal [0,0] when the output signals Vs1, vs2 are less than the signal Va. The boost circuit 268 generates the power supply voltage PVDD having a first voltage level. As the difference between the input signals INP and INN becomes larger, the output signals Vs1, vs2 of the amplifier X1 also increase. The N-bit counter 266 generates an output signal [0,1] when the output signal Vs1, vs2 is greater than the signal Va. The boost circuit 268 generates a new power supply voltage PVDD having a second voltage level that is greater than the first voltage level. Since the amplitude of the periodic signal Vp is determined by the voltage level of the power supply voltage PVDD, when the output signals Vs1, vs2 are increased and larger than the signal Va, the voltage level of the power supply voltage PVDD is increased, so that the amplitude of the periodic signal Vp is also increased. In other words, the amplitude of the periodic signal Vp in the present invention varies with the magnitude of the output signal of the amplifier X1.
While the foregoing has been with reference to the present disclosure, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit of the invention. Accordingly, the scope of the present invention should not be limited to the embodiments disclosed, but should be construed to include various alternatives and modifications without departing from the invention and be covered by the appended claims.
[ symbolic description ]
100 Class D power amplifier circuit
10. Input stage
12. Comparator with a comparator circuit
14. Power output stage
16. Boost circuit
18. Voltage detection circuit
19. Feedback assembly
200,200' class D power amplifier circuit
20. Input stage
22. Comparison unit
222,224 comparator
24. Power output stage
25. Low frequency filter
26. Boost generator
262,264 comparator
266 N-bit counter
268. Boost circuit
27. Periodic signal generator
28,28' feedback assembly
R1, R2 resistance
RF1, RF2 resistor
C1, C2 capacitor
X1 amplifier
Claims (6)
1. A class D power amplifier circuit comprising:
an input stage coupled to a first power supply voltage, the input stage to receive an input voltage at a first node;
a periodic signal generator for generating a periodic signal and a reference signal;
a comparator for comparing the output of the input stage with the periodic signal to generate a first comparison result;
the power output stage is coupled to the second power supply voltage and is used for receiving the comparison result so as to generate a pulse modulation signal; and
a boost generator for comparing the output of the input stage with the reference signal to adjust a voltage value of the second power supply voltage;
wherein the voltage value of the second power supply voltage is larger than the voltage value of the first power supply voltage; and
wherein the reference signal is proportional to the amplitude of the periodic signal, and the amplitude of the periodic signal is determined by the voltage value of the second power supply voltage.
2. The class D power amplifier circuit of claim 1, further comprising a feedback component coupled between the input stage and the power output stage.
3. The class D power amplifier circuit of claim 2, further comprising a low frequency filter for filtering the pulse modulated signal.
4. The class D power amplifier circuit of claim 1, wherein the input stage comprises a double-ended differential input, double-ended differential output amplifier, and the input voltage received by the input stage is a differential pair of audio signals.
5. The class D power amplifier circuit of claim 1, wherein the boost generator comprises:
a comparator for comparing the output of the input stage with the reference signal to generate a second comparison result;
an N-bit counter for receiving the second comparison result to generate an N-bit output signal; and
the boost circuit is used for receiving the N-bit output signal so as to adjust the voltage value of the second power supply voltage.
6. The class D power amplifier circuit of claim 5, wherein the boost circuit is a dc-to-dc voltage converter or a charge pump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010058159.4A CN113141163B (en) | 2020-01-19 | 2020-01-19 | Class D power amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010058159.4A CN113141163B (en) | 2020-01-19 | 2020-01-19 | Class D power amplifier circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113141163A CN113141163A (en) | 2021-07-20 |
| CN113141163B true CN113141163B (en) | 2023-11-17 |
Family
ID=76808690
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010058159.4A Active CN113141163B (en) | 2020-01-19 | 2020-01-19 | Class D power amplifier circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113141163B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2557745A1 (en) * | 1975-02-07 | 1976-08-19 | Nat Semiconductor Corp | ANALOG / DIGITAL SIGNAL CONVERTER CIRCUIT |
| US5701103A (en) * | 1993-06-30 | 1997-12-23 | Kabushiki Kaisha Toshiba | Amplifying circuit with DC voltage feedback to base terminal for magnetic record and playback apparatus |
| US5831475A (en) * | 1997-08-04 | 1998-11-03 | Motorola, Inc. | Method and apparatus for delay matching in a power amplifier |
| KR19990030033A (en) * | 1997-09-22 | 1999-04-26 | 이토 기요시 | Switching Regulator Improves Efficiency at Small Loads |
| CN1497839A (en) * | 2002-10-03 | 2004-05-19 | 三菱电机株式会社 | Class D amplifier |
| CN1666411A (en) * | 2002-07-10 | 2005-09-07 | 因芬尼昂技术股份公司 | Amplifier circuit |
| CN1711678A (en) * | 2002-11-15 | 2005-12-21 | 松下电器产业株式会社 | Power amplifier |
| CN101127510A (en) * | 2006-08-17 | 2008-02-20 | 松下电器产业株式会社 | Differential input class D amplifier |
-
2020
- 2020-01-19 CN CN202010058159.4A patent/CN113141163B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2557745A1 (en) * | 1975-02-07 | 1976-08-19 | Nat Semiconductor Corp | ANALOG / DIGITAL SIGNAL CONVERTER CIRCUIT |
| US5701103A (en) * | 1993-06-30 | 1997-12-23 | Kabushiki Kaisha Toshiba | Amplifying circuit with DC voltage feedback to base terminal for magnetic record and playback apparatus |
| US5831475A (en) * | 1997-08-04 | 1998-11-03 | Motorola, Inc. | Method and apparatus for delay matching in a power amplifier |
| KR19990030033A (en) * | 1997-09-22 | 1999-04-26 | 이토 기요시 | Switching Regulator Improves Efficiency at Small Loads |
| CN1666411A (en) * | 2002-07-10 | 2005-09-07 | 因芬尼昂技术股份公司 | Amplifier circuit |
| CN1497839A (en) * | 2002-10-03 | 2004-05-19 | 三菱电机株式会社 | Class D amplifier |
| CN1711678A (en) * | 2002-11-15 | 2005-12-21 | 松下电器产业株式会社 | Power amplifier |
| CN101127510A (en) * | 2006-08-17 | 2008-02-20 | 松下电器产业株式会社 | Differential input class D amplifier |
Non-Patent Citations (1)
| Title |
|---|
| 新型光纤声光可调滤波器的宽带信号放大器设计;方水平;;激光杂志(第04期);全文 * |
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| Publication number | Publication date |
|---|---|
| CN113141163A (en) | 2021-07-20 |
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