CN112671353B - Low-distortion class-D power amplifier applied to high-power range - Google Patents
Low-distortion class-D power amplifier applied to high-power range Download PDFInfo
- Publication number
- CN112671353B CN112671353B CN202110175480.5A CN202110175480A CN112671353B CN 112671353 B CN112671353 B CN 112671353B CN 202110175480 A CN202110175480 A CN 202110175480A CN 112671353 B CN112671353 B CN 112671353B
- Authority
- CN
- China
- Prior art keywords
- output
- circuit
- current
- voltage
- capacitor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000010752 BS 2869 Class D Substances 0.000 title abstract description 5
- 239000003990 capacitor Substances 0.000 claims abstract description 87
- 238000005070 sampling Methods 0.000 claims abstract description 27
- 230000010355 oscillation Effects 0.000 claims abstract description 16
- 238000001514 detection method Methods 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 8
- 238000004364 calculation method Methods 0.000 claims description 6
- 238000012886 linear function Methods 0.000 claims description 3
- 230000003321 amplification Effects 0.000 abstract description 4
- 238000003199 nucleic acid amplification method Methods 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 10
- 230000005236 sound signal Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- 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
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
-
- 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
Abstract
The invention belongs to the technical field of audio power amplification, and discloses a low-distortion class-D power amplifier applied to a large power range, which comprises the following components: the self-excited internal loop oscillation circuit comprises a voltage control module, a current self-excited internal loop oscillation circuit, a MOS switch circuit, an output LC filter circuit, a nonlinear compensation module and a self-excited oscillation frequency adjustment module, wherein the current self-excited internal loop oscillation circuit is composed of a comparator and an output LC capacitance current sampling feedback circuit of which current feedback is connected with the comparator, the voltage control module is provided with a high-frequency phase control circuit for adjusting the phase delay of the switch frequency of the circuit and eliminating nonlinearity caused by high-frequency fluctuation, the self-excited oscillation frequency adjustment module adjusts the oscillation frequency according to the amplitude of an input signal, narrows the change range of the switch frequency, increases the adaptability of a voltage loop and reduces nonlinear distortion, the output LC capacitance current sampling feedback circuit adopts a mode of connecting a small capacitance of an output capacitor in parallel, and the nonlinear compensation module carries out nonlinear compensation on the circuit and further eliminates the whole signal amplitude distortion of the circuit.
Description
Technical Field
The invention belongs to the technical field of audio power amplification, and discloses a low-distortion class-D power amplifier applied to a large power range.
Background
The class D power amplifier simply refers to an amplifying mode in which the power amplifying element is in a switching operation state. In principle, the audio signal is compared with a high-frequency fixed-frequency signal to obtain a modulation signal of the audio signal on a carrier wave with fixed frequency, namely, the modulation signal is converted into a PWM signal, the PWM signal is amplified into a high-voltage and high-current high-power PWM signal through a switching amplifier, and finally, the high-power audio signal can be restored through a low-pass filter.
The distortion of the digital D-type power amplifier has a unique source compared with the analog power amplifier, a good digital power amplifier circuit can be designed to meet the requirement of high dynamic performance, but fluctuation of the switching frequency is inevitably introduced into a control loop, and the fluctuation is reflected to output by sampling of a switching comparator, so that the digital power amplifier is comparatively distorted. The control loop adjusts not only the dynamic control characteristics but also the phase delay characteristics of the switching frequency. The perfect phase delay characteristic is designed theoretically, so that the sum of the positive and negative trip point voltage fluctuation of the comparator is 0, and the fluctuation does not influence the output although being present, namely the nonlinearity of the high-frequency fluctuation can be eliminated. After the power amplifier distortion is achieved, the full audio frequency range can be smaller than 0.0002 percent.
The existing digital power amplifier has high performance, namely a self-oscillation working mode, and the problem that the oscillation frequency becomes lower along with the increase of the signal amplitude is also solved when the existing digital power amplifier has high performance, and the frequency becomes lower than that of a small signal by 50% or more when the existing digital power amplifier is used for a large signal, so that the control loop must be reduced in speed to transfer the working state of the large signal amplitude. At the same time, the frequency is greatly changed, so that the high-frequency phase control becomes difficult, and the distortion is sharply increased when the large-signal amplitude works. When the signal amplitude is large, the output voltage OUT is close to the power supply VCC, the output inductance current is not triangular wave, but is slightly circular arc deformed, the frequency becomes lower and is more serious, at the moment, the average value of the current peak-to-peak value does not represent the average value of the current, and at the moment, complex nonlinear characteristics are generated.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention discloses a low-distortion class-D power amplifier applied to a large power range, which has the following specific technical scheme:
a low distortion class D power amplifier for high power range comprising: the self-excited current internal loop oscillation circuit comprises a comparator and an output LC capacitance current sampling feedback circuit connected with the comparator through current feedback, wherein the input end of the voltage control module is connected with an input voltage VIN, the output end of the voltage control module outputs a control voltage VM to the input end of the comparator, the output end of the comparator is connected with the input end of the MOS switch circuit, the output end of the MOS switch circuit is connected with the input end of the output LC filter circuit, the output end of the output LC filter circuit is connected with the voltage control module, and the capacitance current of the output LC filter circuit is fed back to the comparator through the output LC capacitance current sampling feedback circuit; the input end of the nonlinear compensation module is connected with the input voltage VIN, and the output end of the nonlinear compensation module outputs a nonlinear compensation function signal to the output end of the voltage control module; the input end of the self-oscillation frequency adjusting module is connected with the input voltage VIN, and the output end of the self-oscillation frequency adjusting module is connected with the comparator.
Furthermore, the voltage control module is provided with a high-frequency phase control circuit, and the high-frequency phase control circuit is provided with a plurality of high-frequency zero poles for accurately adjusting the phase of the switching frequency point.
Further, the output LC capacitive current sampling feedback circuit samples and feeds back the capacitive current of the output LC filter circuit, and one of the following modes is adopted:
a: the output capacitor of the output LC filter circuit is connected in parallel with a small capacitor, the current of the small capacitor is a mirror image of the output capacitor which is reduced in proportion, a virtual ground generating and current detecting module is used for forming a current of which the virtual ground absorbs the current at the lower end of the small capacitor, and the virtual ground generating and current detecting module outputs to obtain an output capacitor current signal;
b: the output capacitor of the output LC filter circuit is connected in parallel with a small capacitor, the current of the small capacitor is a mirror image of the output capacitor which is reduced in proportion, a virtual ground generating and current detecting module is used for forming a current for absorbing the virtual ground at the lower end of the capacitor, the output end of the front-stage circuit is controlled to be connected in series with a resistor to offset the low-frequency part of the mirror image current, and the virtual ground generating and current detecting module outputs a high-frequency part for obtaining an output capacitor current signal;
c: the output capacitor of the output LC filter circuit is connected with a current detection sensor, the sampling current is obtained through detection of the current detection sensor, and the current detection sensor comprises a current transformer or a resistor;
d: the output capacitor of the output LC filter circuit is connected with a small capacitor in parallel, the serial resistor of the small capacitor is grounded, and the sampling is amplified by a resistor voltage amplifier for several times to obtain an approximate output capacitor current signal;
e: the output capacitor of the output LC filter circuit is connected with a small capacitor in parallel, the small capacitor is connected with a front-stage circuit in series to control output, and the high-frequency part of the current signal of the approximate output capacitor is obtained by sampling and amplifying the current signal by a resistor voltage amplifier.
Further, the input end of the virtual ground generating and current detecting module externally presents low resistance, absorbs external current, and the output end outputs a detection value of the current injected from the input end to obtain an output voltage signal v=k×i, wherein K is a constant, and I is the external current.
Further, the virtual ground generation and current detection module uses OPA860 chips or transconductance amplifiers to sink current to form a virtual ground and convert the current to a voltage.
Further, the self-oscillation frequency adjusting module adopts an analog circuit or calculates and adjusts a hysteresis value through an MCU, the analog circuit comprises an RC filter circuit, the RC filter circuit is connected with an input voltage VIN, an output voltage signal VIN2 is used for replacing an output voltage OUT signal, an absolute value of the voltage signal VIN2 and a power supply voltage VCC are output to a function f2 (abs (VIN 2) and VCC) operation circuit, a hysteresis value required when the frequency is stable is obtained, and the frequency is stabilized through a hysteresis amplitude control circuit according to the hysteresis value, wherein the f2 (abs (VIN 2) and VCC) analog circuit is fitted by using a linear function or a broken line method.
Furthermore, the nonlinear compensation module eliminates the full signal amplitude distortion of the circuit by using an analog circuit or through MCU calculation, the analog circuit is provided with an RC filter circuit, the input end of the RC filter circuit is connected with an input voltage VIN, the output voltage VIN2, and meanwhile, a power supply voltage VCC is input to a nonlinear compensation function f1 (VIN 2, VCC) circuit to obtain a compensation value of the circuit.
Further, the nonlinear compensation function f1 (VIN 2, VCC) analog circuit implementation uses a polyline fitting.
The output capacitance current sampling adopts a mirror image mode, small capacitors are connected in parallel, the current to be sampled can be reduced by many times, and then the mirror image capacitance current is acquired, so that the mirror image capacitance current acquisition mode has the advantages of extremely low distortion rate and low cost; the voltage loop is added with carefully designed high-frequency phase control, so that the influence of high-frequency ripple waves in the loop can be greatly eliminated; two benefits may be realized by adjusting the oscillation frequency by the self-oscillation frequency adjustment module according to the input signal amplitude. 1: increasing the minimum operating frequency may cause a faster control loop speed, 2: after the frequency variation is reduced, the design of the control loop switching frequency phase delay becomes simpler; the distortion of the medium-small amplitude signal can be very small after the frequency adjusting circuit is added, but other factors of nonlinear distortion can be generated under the condition of very large signal amplitude, and the nonlinear compensation circuit can eliminate the rest distortion, so that the distortion of the circuit in a very large amplitude range is very low.
Drawings
FIG. 1 is a schematic circuit diagram of the present invention;
FIG. 2 is a schematic diagram of a circuit used in a conventional base voltage control module;
FIGS. 3, 4, 5 and 6 are schematic circuit diagrams of a voltage control module according to an embodiment of the invention;
fig. 7 and 8 are high-frequency ripple and sampling point waveforms of the conventional basic voltage control module when small and large signals are respectively generated;
fig. 9 and 10 are waveforms of high-frequency ripple and sampling point of the voltage control module with high-frequency phase control circuit according to the present invention when small signal and large signal are respectively generated;
FIG. 11 is a BODE diagram of a voltage control module and a base voltage control module with a high frequency phase control circuit according to the present invention;
FIG. 12 is a BODE diagram of a voltage control module circuit with a high frequency phase control circuit according to the present invention;
fig. 13, 14, 15, 16, 17 and 18 are schematic diagrams of circuits for sampling and feeding back the capacitance current of the output LC filter circuit according to the present invention;
FIG. 19a is a schematic diagram of a virtual ground generation and current detection module according to the present invention;
FIG. 19b is a schematic circuit diagram of the virtual ground generation and current detection module of the present invention using OPA860 chips;
FIG. 19c is a schematic diagram of a circuit of the virtual ground generation and current detection module of the present invention using a transconductance amplifier;
FIG. 20 is a schematic diagram of a polyline fitting of the nonlinear compensation function of the present invention;
in the figure, a 1-voltage control module, a 2-comparator, a 3-MOS switching circuit, a 4-output LC filter circuit, a 5-nonlinear compensation module, a 6-output LC capacitance current sampling feedback circuit and a 7-self-oscillation frequency adjusting module.
Detailed Description
In order to make the objects, technical solutions and technical effects of the present invention more apparent, the present invention will be further described in detail with reference to the drawings and examples of the specification.
As shown in fig. 1, a low-distortion class D power amplifier applied to a high power range includes: the self-excited current internal loop oscillation circuit comprises a voltage control module 1, a current self-excited internal loop oscillation circuit, a MOS switch circuit 3, an output LC filter circuit 4, a nonlinear compensation module 5 and a self-excited oscillation frequency adjustment module 7, wherein the current self-excited internal loop oscillation circuit is composed of a comparator 2 and a capacitance current sampling feedback circuit 6 of an output LC of the current feedback connection comparator 2, the input end of the voltage control module 1 is connected with an input voltage VIN, the output end of the voltage control module 1 outputs a control voltage VM to the input end of the comparator 2, the output end of the comparator 2 is connected with the input end of the MOS switch circuit 3, the output end of the MOS switch circuit 3 is connected with the input end of the output LC filter circuit 4, the output end of the output LC filter circuit 4 is connected with the voltage control module 1, and the capacitance current of the output LC filter circuit 4 is fed back to the comparator 2 through the capacitance current sampling feedback circuit 6 of the output LC; the method comprises the steps of carrying out a first treatment on the surface of the The first input end of the nonlinear compensation module 5 is connected with the input voltage VIN, the second input end is connected with the power supply voltage VCC, and the output end outputs a nonlinear compensation function signal to the input end of the comparator 2; the first input end of the self-oscillation frequency adjusting module 7 is connected with the input voltage VIN, the second input end of the self-oscillation frequency adjusting module is connected with the power supply voltage VCC, and the output end of the self-oscillation frequency adjusting module is connected with the comparator 2.
As shown in fig. 2, the circuit of the conventional basic voltage control module includes an operational amplifier U1, a resistor R2, a capacitor C1, and a capacitor C2, where the capacitor C1 and the resistor R2 are connected in parallel, and one end of the capacitor C1 is connected to the output end of the LC filter circuit 4, the other end of the capacitor C2 is connected to one end of the resistor R1, the other end of the capacitor C2 is connected to the output end of the operational amplifier U1, the inverting input of the operational amplifier U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the input voltage VIN, and the output of the circuit is VM1; the circuit can meet the dynamic characteristic of the whole circuit, because the rear-stage current inner loop is equivalent to the first-order characteristic of a current source driving capacitor parallel resistor load, the voltage outer loop is easy to stabilize in practice, the characteristics of quick response and no overshoot can be achieved after the feedback capacitor differential characteristic is added, but the basic circuit does not process high-frequency ripple, and the high-frequency ripple is a main source of nonlinear distortion of the circuit.
The voltage control module 1 of the invention is provided with a high-frequency phase control circuit for processing high-frequency ripple, and the high-frequency phase control circuit comprises the following circuit structures:
as shown in fig. 3, a resistor R3 is added to the basic voltage control module circuit, and after the resistor R3 and a capacitor C1 are connected in series, the resistor end is connected with the output end of the LC filter circuit 4; the output of the circuit is VM2;
as shown in fig. 4, a resistor R3, a resistor R4 and a capacitor C3 are added on the basic voltage control module circuit, the resistor end after the resistor R4 and the capacitor C3 are connected in series is connected with the output end of the LC filter circuit 4, and the resistor end after the resistor R3 and the capacitor C1 are connected in series is connected with the output end of the LC filter circuit 4; the output of the circuit is VM3;
as shown in fig. 5, a resistor R3 and a resistor R5 are added on the basic voltage control module circuit, the resistor R3 and a capacitor C1 are connected in series, the resistor end is connected with the output end of the LC filter circuit 4, and the resistor R5 is arranged between the capacitor C2 and the output end of the operational amplifier U1; the output of the circuit is VM4;
as shown in fig. 6, a primary circuit is added on a basic voltage control module circuit, the added circuit comprises an operational amplifier U2, a resistor R3, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R10, a capacitor C4 and a capacitor C5, the resistor end is connected with the output end of the LC filter circuit 4 after the resistor R3 and the capacitor C1 are connected in series, the resistor R5 is arranged between the capacitor C2 and the output end of the operational amplifier U1, one end of the capacitor C4 is connected with one end of the resistor R7, the other end of the resistor R7 is connected with one end of the resistor R6 and then connected with the reverse input end of the operational amplifier U2, and the other end of the capacitor C4 is connected with the other end of the resistor R6 and then connected with the output end of the operational amplifier U1; the output of the circuit is VM6;
the dynamic characteristics of the circuits in the audio can be kept, but the phases of the switching frequency points can be accurately adjusted by setting a plurality of high-frequency zero poles according to the actual circuit requirement, wherein the resistor R3 can lead the high-frequency phase to lag, the resistor R5 leads the phase to lead, and the complicated phase control aims are as follows: in the switching frequency range, an appropriate phase slope is set. Fig. 6 shows that some circuit structures need to be added with a stage of circuit on the original basis, and a certain phase control can be added on the stage of circuit. After the high-frequency ripple phase is accurately adjusted, the distortion rate can be reduced by two orders of magnitude, and the full audio frequency range is below 0.0002%.
As shown in fig. 7 and 8, the high-frequency ripple and sampling point waveforms of the basic voltage control module are shown, wherein VM1 is the output of the basic voltage control module, sample is the comparator turning point, fig. 7 shows that the high-frequency switch duty ratio is 50% when the signal input level is 0, and fig. 8 shows that the duty ratio deviates by 50% when the signal input level is large. It can be seen that the sampling point of VM1 during switch inversion cannot reflect the average voltage of VM1, and there is actually a large nonlinearity, which is the main nonlinear distortion of the circuit.
As shown in fig. 9 and 10, the high-frequency ripple and sampling point waveform of the voltage control module with the high-frequency phase control circuit of the present invention shifts the phase of the switching frequency point by approximately 90 degrees. When different input signal amplitudes are achieved, the average value of the voltage of the positive and negative switch switching sampling points of VM2 is just the average value of VM2, and at the moment, the influence of the ripple wave of the switching frequency is eliminated. More complex phase control can control more precisely, and after this nonlinear distortion is eliminated, the circuit distortion can reach an extremely low level.
As shown in fig. 11 and 12, VM1 is a basic circuit satisfying the dynamic characteristics of the outer voltage loop, and the dynamic characteristics of the latter circuits are similar, but the phase is adjusted around the switching frequency point of 500 KHZ. VM2 is the simplest circuit which approximately meets the requirement, and compared with VM1, the amplitude of the switching frequency point is greatly attenuated, namely, the voltage ripple is controlled to be reduced, so that nonlinearity is reduced, and meanwhile, the phase of the switching frequency point is greatly adjusted, so that the sum of the voltage fluctuation of the positive and negative jump time points VM2 of the comparator is 0, and the high-frequency ripple factor is counteracted. Both VM3 and VM4 can do corrections including phase slope on the basis of VM2, so that phase control is more accurate.
The invention samples and feeds back the capacitance current of the output LC filter circuit 4, and adopts one of the following modes:
as shown in fig. 13, the output capacitor of the output LC filter circuit 4 is connected in series with a current transformer, and the output capacitor is only ac, so the current transformer detection can work stably, but the magnetic element may have certain nonlinearity, which is not suitable when a very low distortion degree is required;
as shown in fig. 14, the output capacitor of the output LC filter circuit 4 is connected in series with a resistor, and the resistor voltage is amplified to obtain a capacitor current, which has the disadvantages that the resistor has a certain power loss and generates heat and has a little influence on the output voltage;
as shown in fig. 15, the output capacitor of the output LC filter circuit 4 is connected in parallel with a small capacitor, and the small capacitor is connected in series with a resistor and then grounded, and the voltage of the resistor is amplified by several times by a resistor voltage amplifier to be used as an approximate output capacitor current signal. After the resistors are connected in series with the small capacitors, the low-pass filtered signal of the output capacitor current is actually obtained, and the smaller the resistor, the smaller the high-frequency attenuation, so that the voltage amplification with the small resistor is preferable. The resistor with larger size can be used practically without amplification, but the current sampling high-frequency part attenuates more, and the output impedance parameter can be deteriorated.
As shown in fig. 16, the output capacitor of the output LC filter circuit 4 is connected in parallel with a small capacitor, the serial resistor of the small capacitor is connected to the front stage circuit to control the output, the high frequency part of the output capacitor current signal is obtained by amplifying the sample several times through the resistor voltage amplifier, the front stage feedback circuit maintains the virtual ground of the lower end of the small capacitor, however, because the front stage only controls the audio part, the high frequency part or the filter characteristic.
As shown in fig. 17, the output capacitor of the output LC filter circuit 4 is connected in parallel with a small capacitor, the small capacitor current is a mirror image with the output capacitor reduced in proportion, the virtual ground generating and current detecting module is used for forming a current for absorbing the virtual ground at the lower end of the small capacitor, the virtual ground generating and current detecting module outputs to obtain an output capacitor current signal, and meanwhile, the current on the small capacitor can be detected.
In the practical circuit, as shown in fig. 18, in order to make the current self-excited comparator operate near the 0 point, the pre-stage circuit is used to control the series resistance of the output VM (n) to offset the low frequency part of the image current, the remaining high frequency part is generated by virtual ground and absorbed and converted into a high frequency voltage signal by the current detection module, and the signal is compared with the hysteresis voltage above and below the 0 level to generate PWM wave.
Specifically, as shown in fig. 19a, the input end of the virtual ground generating and current detecting module is externally connected with a low resistance, absorbs external current, and the output end outputs a detection value of the current injected from the input end, so as to obtain an output voltage signal v=k×i, where K is a constant, and I is the external current.
As shown in fig. 19b and 19c, the virtual ground generation and current detection module may use an OPA 860-like chip or a transconductance amplifier to sink current to form a virtual ground and convert the current to a voltage.
The feedback of the capacitive current of the output LC filter circuit 4 comprises an output inductor current and a load current, the inductor current feedback providing the circuit dynamic characteristics and stability, the load current feedback enabling the output impedance to reach an extremely low level.
The self-oscillation frequency adjusting module 7 is used for dynamically adjusting the stability of the switching frequency, so that the circuit performance is greatly improved.
The self-oscillation frequency adjusting module 7 adopts an analog circuit or calculates and adjusts a hysteresis value through an MCU so as to stabilize the frequency, the analog circuit comprises an RC filter circuit, the RC filter circuit is connected with an input voltage VIN for replacing output voltage, and outputs a voltage signal VIN2, the output voltage signal VIN2 can simulate the phase lag of an output voltage OUT relative to the input voltage VIN, so that the output voltage signal VIN2 can replace the output voltage OUT to be used for calculation, the absolute value of the voltage signal VIN2 and a power supply voltage VCC are output to a function f2 (abs (VIN 2) and VCC), the hysteresis value required when the frequency is stabilized is obtained, and the frequency is stabilized through a hysteresis amplitude control circuit according to the hysteresis value, wherein the f2 (abs (VIN 2) and VCC) analog circuit can be used for realizing a certain simplification and using a linear function or a polyline method to fit. The MCU calculation implementation can obtain any f2 () function.
Nonlinear distortion of the circuit comes from another aspect in addition to the effect of the high frequency ripple on the control circuit. When the signal amplitude is large, the output voltage OUT is close to the power supply voltage VCC, the output inductance current is not triangular wave, but is slightly circular arc deformed, at the moment, the average value of the current peak-to-peak value does not represent the average value of the current, and at the moment, complex nonlinear characteristics are generated. The nonlinear compensation module 5 of the invention eliminates the whole signal amplitude distortion of the circuit by using an analog circuit or by MCU calculation, the analog circuit realizes the default VCC constant and uses a broken line method for fitting, and the MCU calculation realization mode can obtain any f1 () function.
The analog circuit is provided with an RC filter circuit, the input end of the RC filter circuit is connected with an input voltage VIN, the output end of the RC filter circuit outputs a signal to a nonlinear compensation function circuit, and meanwhile, a power supply voltage VCC is input to a nonlinear compensation function f1 (VIN 2, VCC) circuit to obtain a compensation value of the circuit, so that nonlinear distortion of the circuit is eliminated. As shown in fig. 20, for simplicity, the power supply voltage VCC can be ignored because of being relatively stable, the nonlinear compensation function analog circuit implementation can be default VCC constant and fit by using a polyline method, and the circuit implementation is relatively simple.
Claims (8)
1. A low distortion class D power amplifier for high power range comprising: the self-excited internal loop oscillation circuit is characterized by further comprising a nonlinear compensation module (5) and a self-excited oscillation frequency adjustment module (7), wherein the self-excited internal loop oscillation circuit consists of a comparator (2) and an output LC capacitance current sampling feedback circuit (6) connected with the comparator (2) through current feedback, the input end of the voltage control module (1) is connected with an input voltage VIN, the output end of the voltage control module outputs a control voltage VM to the input end of the comparator (2), the output end of the comparator (2) is connected with the input end of the MOS switch circuit (3), the output end of the MOS switch circuit (3) is connected with the input end of the output LC filter circuit (4), the output end of the output LC filter circuit (4) is connected with the voltage control module (1), and the capacitance current of the output LC filter circuit (4) is fed back to the comparator (2) through the output LC capacitance current sampling feedback circuit (6); the first input end of the nonlinear compensation module (5) is connected with the input voltage VIN, the second input end of the nonlinear compensation module is connected with the power supply voltage VCC, and the output end of the nonlinear compensation module outputs a nonlinear compensation function signal to the input end of the comparator (2); the first input end of the self-oscillation frequency adjusting module (7) is connected with the input voltage VIN, the second input end of the self-oscillation frequency adjusting module is connected with the power supply voltage VCC, and the output end of the self-oscillation frequency adjusting module is connected with the comparator (2).
2. A low distortion class D power amplifier applied in high power range as claimed in claim 1, wherein said voltage control module (1) is provided with a high frequency phase control circuit, said high frequency phase control circuit setting a plurality of high frequency poles zero to precisely adjust the phase of the switching frequency point.
3. A low distortion class D power amplifier applied to a high power range according to claim 1, wherein the output LC capacitive current sampling feedback circuit (6) samples and feeds back the capacitive current of the output LC filter circuit (4) in one of the following ways:
a: the output capacitor of the output LC filter circuit (4) is connected in parallel with a small capacitor, the current of the small capacitor is a mirror image of the output capacitor which is reduced in proportion, a virtual ground generating and current detecting module is used for forming a current of which the virtual ground absorbs the current at the lower end of the capacitor, and the virtual ground generating and current detecting module outputs to obtain an output capacitor current signal;
b: the output capacitor of the output LC filter circuit (4) is connected in parallel with a small capacitor, the current of the small capacitor is a mirror image of the output capacitor which is reduced in proportion, a virtual ground generating and current detecting module is used for forming a current for absorbing the current of the small capacitor at the lower end of the small capacitor, the output end of the front-stage circuit is controlled to be connected in series with a resistor to counteract a low-frequency part of the mirror image current, and the virtual ground generating and current detecting module outputs a high-frequency part for obtaining an output capacitor current signal;
c: an output capacitor of the output LC filter circuit (4) is connected with a current detection sensor, sampling current is obtained through detection of the current detection sensor, and the current detection sensor comprises a current transformer or a resistor;
d: the output capacitor of the output LC filter circuit (4) is connected in parallel with a small capacitor, the series resistance of the small capacitor is grounded, and the sampling is amplified by a resistor voltage amplifier for several times to obtain an approximate output capacitor current signal;
e: the output capacitor of the output LC filter circuit (4) is connected with a small capacitor in parallel, the serial resistor of the small capacitor is connected with the front-stage circuit to control the output, and the high-frequency part of the current signal of the approximate output capacitor is obtained by sampling and amplifying the current signal by a resistor voltage amplifier.
4. A low distortion class D power amplifier for high power range as claimed in claim 3, wherein said virtual ground generating and current detecting module has an input end which exhibits low resistance to the outside, absorbs an external sink current, and an output end which outputs a detected value of the sink current from the input end to obtain an output voltage signal v=k×i, where K is a constant and I is said external sink current.
5. A low distortion class D power amplifier for high power range as set out in claim 4, wherein said virtual ground generation and current detection module uses an OPA860 chip or transconductance amplifier to sink current to form a virtual ground and convert the current to a voltage.
6. A low distortion class D power amplifier applied to a high power range as claimed in claim 1, wherein the self-oscillation frequency adjusting module (7) uses an analog circuit or is calculated by an MCU to obtain and adjust a hysteresis value, the analog circuit comprises an RC filter circuit, the RC filter circuit is connected to an input voltage VIN, an output voltage signal VIN2 is used to replace an output voltage OUT signal, an absolute value of the voltage signal VIN2 and a power voltage VCC to a function f2 (abs (VIN 2), VCC) operation circuit are output, a hysteresis value required when the frequency is stable is obtained, and the frequency is stabilized by a hysteresis amplitude control circuit according to the hysteresis value, wherein the f2 (abs (VIN 2), VCC) analog circuit is fitted by using a linear function or a polyline method.
7. A low distortion class D power amplifier for high power range according to claim 1, characterized in that the nonlinear compensation module (5) uses an analog circuit or by MCU calculation to eliminate the full signal amplitude distortion of the circuit, the analog circuit is provided with an RC filter circuit, the input terminal of the RC filter circuit is connected with the input voltage VIN, the output voltage VIN2, and the power supply voltage VCC is input to the nonlinear compensation function f1 (VIN 2, VCC) circuit to obtain the compensation value of the circuit.
8. A low distortion class D power amplifier for high power range as recited in claim 7, wherein said nonlinear compensation function f1 (VIN 2, VCC) analog circuit implementation uses a polyline method fit.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110175480.5A CN112671353B (en) | 2021-02-09 | 2021-02-09 | Low-distortion class-D power amplifier applied to high-power range |
| PCT/CN2021/078065 WO2022170645A1 (en) | 2021-02-09 | 2021-02-26 | Low-distortion class d power amplifier applied to high-power range |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110175480.5A CN112671353B (en) | 2021-02-09 | 2021-02-09 | Low-distortion class-D power amplifier applied to high-power range |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112671353A CN112671353A (en) | 2021-04-16 |
| CN112671353B true CN112671353B (en) | 2024-02-13 |
Family
ID=75399207
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110175480.5A Active CN112671353B (en) | 2021-02-09 | 2021-02-09 | Low-distortion class-D power amplifier applied to high-power range |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN112671353B (en) |
| WO (1) | WO2022170645A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115128664B (en) * | 2022-09-01 | 2022-11-08 | 中国科学院地质与地球物理研究所 | Seismic acquisition system based on frequency domain broadening MEMS sensor |
| CN117134715B (en) * | 2023-10-26 | 2024-01-26 | 苏州仁正智探科技有限公司 | Induction type oil liquid abrasive dust micro-signal two-stage amplification processing system and method |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101093644B1 (en) * | 2010-07-15 | 2011-12-15 | 전북대학교산학협력단 | Analog feedback linear power amplifier using negative group delay circuits |
| JP2013207534A (en) * | 2012-03-28 | 2013-10-07 | Pioneer Electronic Corp | Multichannel amplifier, method of controlling multichannel amplifier, and program |
| CN104348427A (en) * | 2013-07-29 | 2015-02-11 | 安凯(广州)微电子技术有限公司 | Class D audio power amplifier circuit, power amplifier and audio player |
| CN110912524A (en) * | 2019-12-11 | 2020-03-24 | 深圳市芯生半导体有限公司 | Class D power amplifier oscillation circuit, class D power amplifier oscillator and frequency adjusting method thereof |
| CN111740714A (en) * | 2020-07-27 | 2020-10-02 | 张金路 | Filter capacitor current feedback self-oscillation audio digital power amplifier |
| CN111884608A (en) * | 2020-08-03 | 2020-11-03 | 广芯电子技术（上海）股份有限公司 | Class D audio power amplifier and sampling triangular wave generating and filtering circuit used therein |
| CN111900944A (en) * | 2020-07-27 | 2020-11-06 | 张金路 | Composite parallel connection type audio digital power amplifier without dead zone distortion |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7027780B2 (en) * | 2003-09-30 | 2006-04-11 | Broadcom Corporation | Technique for improving modulation performance of translational loop RF transmitters |
| JP5253413B2 (en) * | 2006-12-21 | 2013-07-31 | バング アンド オルフセン アイスパワー アクティーゼルスカブ | Error correction system for class D power stage |
| US20110292699A1 (en) * | 2010-05-26 | 2011-12-01 | Texas Instruments Incorporated | Systems and Methods for Distortion Reduction |
| EP2784940B1 (en) * | 2013-03-28 | 2015-03-18 | Asahi Kasei Microdevices Corporation | Voltage-controlled oscillator module and phase-locked loop device including the same |
| JP2017073583A (en) * | 2015-10-05 | 2017-04-13 | ヤマハ株式会社 | Class D amplifier |
| CN111541430B (en) * | 2020-05-21 | 2023-05-12 | 张金路 | Composite serial digital power amplifier |
| CN212305266U (en) * | 2020-07-27 | 2021-01-05 | 张金路 | Filter capacitor current feedback self-oscillation audio digital power amplifier |
-
2021
- 2021-02-09 CN CN202110175480.5A patent/CN112671353B/en active Active
- 2021-02-26 WO PCT/CN2021/078065 patent/WO2022170645A1/en active Application Filing
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101093644B1 (en) * | 2010-07-15 | 2011-12-15 | 전북대학교산학협력단 | Analog feedback linear power amplifier using negative group delay circuits |
| JP2013207534A (en) * | 2012-03-28 | 2013-10-07 | Pioneer Electronic Corp | Multichannel amplifier, method of controlling multichannel amplifier, and program |
| CN104348427A (en) * | 2013-07-29 | 2015-02-11 | 安凯(广州)微电子技术有限公司 | Class D audio power amplifier circuit, power amplifier and audio player |
| CN110912524A (en) * | 2019-12-11 | 2020-03-24 | 深圳市芯生半导体有限公司 | Class D power amplifier oscillation circuit, class D power amplifier oscillator and frequency adjusting method thereof |
| CN111740714A (en) * | 2020-07-27 | 2020-10-02 | 张金路 | Filter capacitor current feedback self-oscillation audio digital power amplifier |
| CN111900944A (en) * | 2020-07-27 | 2020-11-06 | 张金路 | Composite parallel connection type audio digital power amplifier without dead zone distortion |
| CN111884608A (en) * | 2020-08-03 | 2020-11-03 | 广芯电子技术（上海）股份有限公司 | Class D audio power amplifier and sampling triangular wave generating and filtering circuit used therein |
Non-Patent Citations (1)
| Title |
|---|
| 集成运算放大器的选择与使用的探讨;宋世全;广州航海高等专科学校学报(第01期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112671353A (en) | 2021-04-16 |
| WO2022170645A1 (en) | 2022-08-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4589665B2 (en) | Amplifier and high-frequency power amplifier using the same | |
| JP3899074B2 (en) | Digital PWM input class D acoustic amplifier with PWM negative feedback | |
| CN100433548C (en) | Power amplifier | |
| AU754082B2 (en) | Amplifier circuit | |
| CN112671353B (en) | Low-distortion class-D power amplifier applied to high-power range | |
| EP2041867B1 (en) | Amplifier employing interleaved signals for pwm ripple suppression | |
| TWI477064B (en) | A system and method for reducing distortion in an audio amplification system | |
| CN101297475A (en) | Method and arrangement for optimizing efficiency of a power amplifier | |
| WO2003061117A1 (en) | Class d electroacoustic amplifier and method for compensation of power supply voltage influence on output audio signal in class d electroacoustic amplifier | |
| CN111580587B (en) | Pulse width modulation type constant current source circuit | |
| US8525593B2 (en) | Circuit and method for amplifying a digital signal | |
| CN212305266U (en) | Filter capacitor current feedback self-oscillation audio digital power amplifier | |
| CN109104180B (en) | Electronic information data processing system | |
| CN102447410B (en) | AC-DC power supply changeover device and loop compensation circuit thereof | |
| US9444439B2 (en) | Pulse generating circuit for audio-frequency amplifiers and regulated power supplies | |
| US11784615B2 (en) | Class-D amplifier with nested feedback loops | |
| Bellili et al. | Low power class D audio amplifier with high performance and high efficiency | |
| CN111740714A (en) | Filter capacitor current feedback self-oscillation audio digital power amplifier | |
| CN104201996A (en) | Feedback circuit for D type power amplifier and electronic equipment | |
| Hietakangas et al. | 1.8 W, 19 MHz envelope amplifier for envelope tracking and envelope elimination and restoration | |
| Pillonnet et al. | A topological comparison of PWM and hysteresis controls in switching audio amplifiers | |
| CN113467312B (en) | Device for generating excitation signal of rotary transformer | |
| CN219625576U (en) | Alternating current signal source generating device for cable detection | |
| CN220325507U (en) | Interleaved parallel PFC self-adaptive current detection circuit under wide-area working condition | |
| Ng et al. | A 94% efficiency near-constant frequency self-oscillating class-D audio amplifier with voltage control resistor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |