CN116566347A - Audio device and power supply control method with gain control - Google Patents
Audio device and power supply control method with gain control Download PDFInfo
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
- G05F3/02—Regulating voltage or current
- G05F3/08—Regulating voltage or current wherein the variable is dc
- G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
- G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
- G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
- G05F3/24—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations wherein the transistors are of the field-effect type only
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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
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
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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
- H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
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Abstract
The invention discloses an audio device and a power supply control method with gain control, which are characterized in that whether an output signal is truncated or not is detected by monitoring the output signal of an integrator, a gain control signal is generated to adjust the amplitude of the output signal, meanwhile, a boost control signal is generated by detecting the output signal of the integrator, and the boost voltage is controlled to meet the requirement of outputting a sound signal, so that the distortion of the output signal is reduced, the boost voltage is attached to the output signal as much as possible, the efficiency is improved, and the working time is prolonged.
Description
Technical Field
The invention relates to the technical field of audio power amplification, in particular to an audio device and a power supply control method with gain control.
Background
As portable devices and electric vehicles are increasingly demanded, battery powered applications are becoming more and more widespread, and in the case of battery powered applications, a power converter is often required to convert the voltage of the battery to the required voltage.
In the application of the class D amplifier, in order to realize a larger loudness, a larger power is required to be output, at this time, the voltage of the battery needs to be raised to a higher voltage to supply power for the class D amplifier, and the boosting process needs additional power consumption, so that efficiency is reduced, additional energy consumption loss is brought, and the higher the boosting efficiency is, the lower the boosting efficiency is, and the larger the energy consumption loss is under the condition of the same output power.
For the class-D amplifier, the higher the power supply voltage, the larger the switching loss and the lower the efficiency, and in a battery-powered system, the higher the requirement on the working time, the higher the power supply voltage of the class-D amplifier, the energy consumption loss caused by the higher power supply voltage can also reduce the working time of the system.
In addition, if the input signal increases rapidly, the speed at which the supply voltage of the class D amplifier increases does not match the speed at which the signal increases, and the output signal may be truncated, resulting in distortion and noise.
Therefore, how to reduce the distortion of the output signal and balance the energy consumption loss caused by increasing the power supply voltage is a technical problem to be solved.
Disclosure of Invention
The invention aims to provide an audio device and a power supply control method with gain control, which can adjust the amplitude of an output signal by generating a gain control signal, reduce the distortion of the output signal and control the power supply voltage to be attached to the output sound signal as much as possible, thereby improving the efficiency and prolonging the working time.
In order to achieve the above object, the present invention provides an audio device including a class D amplifier and a boost controller;
the class-D amplifier comprises an integrating filter, a triangular wave generator, a gain control component and a boost control component;
the integrating filter is used for outputting an integrator; the triangular wave generator is used for setting a boosting threshold comparison voltage and outputting a modulating triangular wave peak value; the gain control component is used for comparing the output of the integrator with the peak value of the modulated triangular wave and outputting a gain control signal so as to adjust the gain of an input signal and further adjust the amplitude of an output signal; the boost control component is configured to generate a boost control signal to change a power of the boost controller to power the class D amplifier.
Optionally, the gain control component comprises a truncated comparator, a gain controller and a variable gain amplifier;
the truncated comparator is used for sampling the output of the integrator and comparing the output with the modulation triangular wave peak value, and sending out a gain control signal when the output of the integrator exceeds the modulation triangular wave peak value;
the gain control signal controls a gain controller to adjust the variable gain amplifier, thereby adjusting the amplitude of the output signal.
Optionally, the gain controller is configured to gradually attenuate the gain of the input signal according to the start time of the gain controller, and reduce the amplitude of the output signal; and gradually recovering the gain of the input signal according to the release time of the gain controller, and increasing the amplitude of the output signal.
Optionally, the boost control component includes a boost comparator, a boost control signal generator, and a boost controller, where the boost comparator is configured to sample the output of the integrator and compare with the boost threshold comparison voltage, control the boost control signal generator to generate the boost control signal, and the boost control signal changes the power of the boost controller for supplying power to the class D amplifier.
The invention also provides a power supply control method with gain control, which adopts the audio device as described above and comprises the following steps:
comparing the output of the integrator with the modulating triangular wave peak value, and judging whether the output signal is truncated or not;
if the output signal is truncated, sending out the gain control signal, and gradually attenuating the gain of the input signal to reduce the amplitude of the output signal;
when the output signal is not truncated, sending out the gain control signal, and gradually recovering the gain of the input signal to increase the amplitude of the output signal;
setting a high threshold comparison voltage and a low threshold comparison voltage, comparing the integrator output with the high threshold comparison voltage and the low threshold comparison voltage to generate the boost control signal;
and changing the power of the boosting controller for supplying power to the class-D amplifier through the boosting control signal.
Optionally, the determining whether the output signal is truncated includes: and if the output of the integrator exceeds the modulation triangular wave peak value, judging that the output signal is truncated.
Optionally, the gain of the input signal is gradually attenuated according to the start time of the gain controller, and the gain of the input signal is gradually recovered according to the release time of the gain controller.
Optionally, said comparing said integrator output to said high threshold comparison voltage and said low threshold comparison voltage comprises: when the integrator output is higher than the high threshold comparison voltage, the boost control signal controls a power supply to boost; the boost control signal controlling the power supply to decrease when the integrator output is below the low threshold comparison voltage; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
Optionally, the step-up control signal changing the power of the step-up controller for supplying the class D amplifier includes: the boost control signal is connected with an error amplifier of the boost controller, and the higher the boost control signal is, the higher the power supply is; and when the power supply is smaller than or equal to the input voltage, the boost controller enters a through mode, and the power supply is equal to the input voltage.
Optionally, the generating the boost control signal includes: the boost control signal is generated by means of resistive voltage division.
Optionally, when the output of the integrator is higher than the high threshold comparison voltage, the reversible counter counts up, the effective bit of the switch control signal rises gradually, and the boost control signal increases gradually; when the integrator output is lower than the low threshold comparison voltage, the reversible counter counts down, the switch control signal valid bit is gradually reduced, and the boost control signal is gradually reduced; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
Optionally, the generating the boost control signal further includes: the boost control signal is generated by means of a switch and a capacitor.
Optionally, when the integrator output is higher than the high threshold comparison voltage, charging a first capacitor of the capacitors to continuously increase the boost control signal; discharging the first capacitor when the integrator output is lower than the low threshold comparison voltage, and continuously reducing the boost control signal; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
Optionally, the step-up control signal changing the power of the step-up controller for supplying power to the class D amplifier further includes: the boost control signal is connected with a voltage division network of the power supply through a resistor.
Optionally, the generating the boost control signal includes: the boost control signal is generated by means of resistive voltage division.
Optionally, when the integrator output is higher than the high threshold comparison voltage, the reversible counter counts up, the switch control signal valid bit rises gradually, and the boost control signal decreases gradually; when the integrator output is lower than the low threshold comparison voltage, the reversible counter counts down, the switch control signal valid bit is gradually reduced, and the boost control signal is gradually increased; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
Optionally, the generated boost control signal further comprises: the boost control signal is generated by means of a switch and a capacitor.
Optionally, discharging a first capacitor of the capacitors when the integrator output is higher than the high threshold comparison voltage, and continuously reducing the boost control signal; charging the first capacitor when the integrator output is lower than the low threshold comparison voltage, and continuously raising the boost control signal; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
Compared with the prior art, the invention has the advantages and positive effects that: the output signal of the integrator is compared with the modulating triangular wave peak value to judge whether the output signal is truncated or not, a gain control signal is generated to adjust the amplitude of the output signal, distortion of the output signal is reduced, meanwhile, a boost control signal is generated by monitoring the output signal of the integrator, and the boost voltage is controlled to meet the requirement of outputting a sound signal, so that the boost voltage is attached to the output signal as much as possible, the efficiency is improved, and the working time is prolonged.
Drawings
Fig. 1 is a schematic diagram of a circuit structure of boost control of a power supply according to an embodiment of the present invention;
FIG. 2 is a second schematic circuit diagram of boost control of a power supply according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the on-resistance of a power transistor according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of the proportional relationship between the integrator output amplitude, the modulated triangular wave amplitude, the output signal amplitude and the maximum output amplitude in the embodiment of the present invention;
FIG. 5 is a schematic circuit diagram of a boost controller according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a circuit structure of another boost controller according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a circuit structure of a boost control signal generator according to an embodiment of the invention;
FIG. 8 is a schematic diagram of a second circuit configuration of the boost control signal generator according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of a third circuit configuration of the boost control signal generator according to an embodiment of the present invention;
FIG. 10 is a diagram illustrating a fourth circuit configuration of the boost control signal generator according to an embodiment of the present invention;
FIG. 11 is a schematic diagram showing the variation relationship among the output signal, the power supply, the gain of the power amplifier and the input signal according to the embodiment of the invention;
fig. 12 is a flowchart of a power supply control method with gain control according to an embodiment of the present invention.
Detailed Description
The present invention will be described in more detail below with reference to the drawings, in which preferred embodiments of the invention are shown, it being understood that one skilled in the art can modify the invention herein described while still achieving the advantageous effects of the invention. Accordingly, the following description is to be construed as broadly known to those skilled in the art and not as limiting the invention.
The invention is more particularly described by way of example in the following paragraphs with reference to the drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.
In the working process of the class D amplifier, the sound of the audio device is big or small, so the audio device cannot be always in a high-power working state, only the big sound is played, the high voltage boosting is needed, only the low voltage boosting is needed, even the small sound is not boosted, the requirement can be met, and therefore the voltage boosting is closer to the voltage needed by sound playing, the smaller the efficiency loss is, and the longer the working time is.
In the process of actually controlling the audio device, since the boosted charging current is limited, the rising speed of the power supply voltage of the class D amplifier is limited, if the input signal increases rapidly, the rising speed of the power supply voltage of the class D amplifier cannot catch up with the rising speed of the signal, the output signal may be truncated, resulting in distortion and noise, and in order to avoid the generation of truncated distortion, a certain margin needs to be set, so that the power supply voltage is boosted to a higher voltage in advance, but the overall efficiency is reduced.
According to the scheme, when an input signal is smaller, the output power supply does not need to boost, the power supply starts to boost after the output signal is increased, the boosting speed is limited, the output signal is truncated, the AGC is started, the gain of the power amplifier is reduced, the output is not truncated and distorted any more, the maximum output amplitude of the output signal is larger and larger along with the continuous rising of the PVDD voltage, and the gain of the power amplifier is gradually recovered.
An audio device is provided in this embodiment, please refer to fig. 1-2, including a class D amplifier and a boost controller.
The class D amplifier comprises an integrating filter, a triangular wave generator, a gain control component and a boost control component;
the integrating filter is used for outputting Vint from the integrator; the triangular wave generator is used for setting the boosting threshold comparison voltages Vth and Vtl and outputting a modulating triangular wave peak value Vr; the gain control component is used for comparing the output of the integrator with the peak value of the modulated triangular wave and outputting a gain control signal so as to adjust the gain of an input signal and further adjust the amplitude of an output signal Vo; the boost control component is configured to generate a boost control signal Vco to change a power PVDD that the boost controller powers the class D amplifier.
The gain control component is used for judging whether the output signal is truncated or not and adjusting the gain.
The gain control component includes a truncated comparator, an AGC (gain) controller, and a variable gain amplifier.
The truncated comparator is used for comparing the output Vint of the sampling integrator with the modulated triangular wave peak value Vr, and when the output of the integrator exceeds the modulated triangular wave peak value, the output signal Vo is judged to have truncated, a gain control signal is output, the AGC controller is controlled to adjust the gradual attenuation gain or the restoration gain of the variable gain amplifier, and then the amplitude of the output signal Vo is adjusted.
Specifically, the AGC is configured to gradually attenuate the gain of the input signal according to the start time of the gain controller, reduce the amplitude of the output signal, and gradually recover the gain of the input signal according to the release time of the gain controller after the output signal is no longer truncated, so as to increase the amplitude of the output signal.
The boost control component comprises a boost comparator and a boost control signal generator, wherein the boost controller is used for generating a power supply to supply power for the class-D amplifier, the class-D amplifier converts an input signal Vin into an output signal Vo with driving capability, and meanwhile, the boost control signal is generated to control the boost controller to output a power supply PVDD.
Specifically, the boost comparator samples the output of the integrator and compares the output with the boost threshold comparison voltage, controls the boost control signal generator to generate the boost control signal, and changes the power PVDD of the boost controller for supplying power to the class-D amplifier.
The embodiment also provides a power supply control method with gain control, which comprises the following steps:
s1, comparing the output of the integrator with the modulating triangular wave peak value, and judging whether the output signal is truncated or not;
s2, if the output signal is truncated, sending out a gain control signal, and gradually attenuating the gain of the input signal to reduce the amplitude of the output signal;
s3, when the output signal is not truncated, sending out a gain control signal, and gradually recovering the gain of the input signal to increase the amplitude of the output signal;
s4, setting a high threshold comparison voltage and a low threshold comparison voltage, and comparing the output of the integrator with the high threshold comparison voltage and the low threshold comparison voltage to generate a boost control signal Vco;
s5, changing the power PVDD for supplying power to the class D amplifier by the boost controller through a boost control signal Vco.
Referring to fig. 1-2, the boost controller generates a power supply (PVDD) to supply power to the class D amplifier, and the class D amplifier converts an input signal (Vin) into an output signal (Vo) with driving capability, and generates a boost control signal Vco to control the boost controller to output the appropriate power supply PVDD.
The signal path of the class D amplifier is a variable gain amplifier, an integrating filter, a PWM (pulse width modulation) comparator and an output stage.
The integrator output Vin is compared with a modulated triangular wave signal (Vtri) in a PWM comparator to generate a PWM output signal related to the amplitude of the input signal Vin, which is passed through an output stage to generate a driving output signal Vo.
In step S1, the boost comparator samples the integrator output Vint to determine whether the output signal is truncated and the required power supply PVDD, including boosting, dropping, or unchanged.
Further, the step of judging whether the truncated end is present comprises the steps of: and if the output of the integrator exceeds the modulation triangular wave peak value, judging that the output signal is truncated.
In step S2, after the output signal is truncated, the truncated comparator sends out a gain control signal to control the AGC (gain control) controller to adjust the variable gain amplifier, and the gain is gradually attenuated according to the start time of the AGC, so as to reduce the amplitude of the output signal.
In step S3, after the output signal is no longer truncated, the gain control signal is sent out, the gain is gradually recovered according to the release time of the AGC, and the amplitude of the output signal is increased.
Referring to fig. 3, due to the on-resistance of the power tube and the voltage division of the load, the maximum output signal amplitude Vomax is smaller than the power supply PVDD, and the relationship between the two can be as follows:
，
where Vomax is the maximum output signal amplitude, PVDD is the power supply, RL is the on-resistance, rdsonH is the on-resistance of the high side power tube connected to PVDD, rdsonL is the on-resistance of the low side power tube connected to GND.
The manner in which the sampled power supply PVDD is compared with the input signal, the output signal, is not accurate, as the maximum output signal amplitude is Vomax, instead of the power supply PVDD, as is commonly used in the prior art.
In addition, referring to fig. 4, the proportional relationship between the integrator output amplitude Vint and the modulated triangular wave amplitude Vr and the proportional relationship between the output signal amplitude Vo and the maximum output amplitude Vomax are corresponding, that is:
the amplitude of the power supply PVDD required by the output signal Vo can be more reasonably determined by detecting Vint.
The triangular wave generator is provided with a boosting threshold comparison voltage, a high threshold comparison voltage Vth and a low threshold comparison voltage Vtl, which are related to the triangular wave amplitude.
In step S4, when the integrator output is higher than Vth, the boost control signal controls the boost controller to boost the power supply PVDD, when the integrator output is lower than Vtl, the boost control signal controls the boost controller to lower the power supply PVDD, and when the integrator output is not lower than the low threshold comparison voltage and not higher than the high threshold comparison voltage, the boost control signal remains unchanged.
Further, in the embodiment of the present invention, referring to fig. 5-6, the step-up controller receives the step-up control signal in two ways:
s501, a boost control signal is directly connected with an error amplifier of a boost controller.
S502, a boosting control signal is connected with a voltage division network of PVDD through a resistor R3.
Specifically, in step S501, the boost control signal is directly connected to the error amplifier of the boost controller, and in this case, the boost control signal corresponds to the reference signal of the error amplifier, and the higher the boost control signal, the higher the PVDD.
In addition, when pvdd+.vin, the boost controller enters a pass-through mode, i.e., pvdd=vin.
Specifically, in step S502, the boost control signal Vco is connected to the voltage divider network of PVDD through the resistor R3, and at this time,
。
wherein Vref is a reference voltage, PVDD is a power supply, vco is a boost control signal, R1 is a first resistor, R2 is a second resistor, and R3 is a third resistor.
The lower the boost control signal, the higher the PVDD, and when the boost control signal is 0, the PVDD is at most。
Wherein Vref is a reference voltage, PVDD is a power supply, R1 is a first resistor, R2 is a second resistor, and R3 is a third resistor.
Further, when the boost control signal is directly connected to the error amplifier of the boost controller, two ways of generating the boost control signal in step S5 are respectively:
s5011, a boost control signal is generated by means of resistor voltage division.
Referring to FIG. 7, the up-down counter of the boost control generator receives the output of the boost comparator, and when Vint > Vth, the up-down counter counts up, the effective bit of the switch control signal S < n:0> rises gradually, and the boost control signal increases gradually.
When Vint < Vtl, the reversible counter counts down, the effective bit of the switch control signal S < n:0> is gradually reduced, and the boost control signal is gradually reduced.
When Vtl is less than or equal to Vint and less than or equal to Vth, the boost control signal remains unchanged.
Wherein the rising speed of the boost control signal is controlled by the start time, and the falling speed of the boost control signal is controlled by the release time.
S5012, a boost control signal is generated by means of a switched capacitor.
Referring to fig. 8, when Vint > Vth, the buck-boost controller of the boost control generator receives the output of the boost comparator, and needs to charge the first capacitor C1, sa is turned on, sb is turned off, sc is turned on first to charge C0 to the reference voltage, sc is turned off, sd is turned on, C0 charges C1, sd is turned off again, and the boost control signal Vco is continuously increased, where the boost control signal Vco specifically indicates:
wherein Vref is a reference voltage, vco is a boost control signal, C1 is a first capacitor, C0 is a capacitor for charging C1, and n is the number of times of charging.
When Vint < Vtl, the first capacitor C1 needs to be discharged, sa is turned off, sb is turned off, sc is turned on first for each discharge period, charges of C0 are discharged, sc is turned off, sd is turned on, C1 discharges C0, sd is turned off again, and the boost control signal Vco is reduced continuously, wherein the boost control signal Vco specifically indicates:
where Voc is the original control voltage, vco is the boost control signal, C1 is the first capacitance, C0 is the capacitance that discharges C1, and n is the number of discharges.
When Vtl is less than or equal to Vint and less than or equal to Vth, the boost control signal remains unchanged. Wherein the rising speed of the boost control signal is controlled by the start time, and the falling speed of the boost control signal is controlled by the release time.
Further, when the boost control signal is connected to the voltage divider network of PVDD through the resistor R3, two ways of generating the boost control signal in step S4 are respectively:
and S5021, generating a boost control signal by means of resistor voltage division.
Referring to FIG. 9, the reversible counter of the boost control generator receives the output of the boost comparator, and counts up when Vint > Vth, the effective bit of the switch control signal S < n:0> is gradually increased, and the boost control signal is gradually decreased.
When Vint < Vtl, the reversible counter counts down, the effective bit of the switch control signal S < n:0> is gradually reduced, and the boost control signal is gradually increased.
When Vtl is less than or equal to Vint and less than or equal to Vth, the boost control signal remains unchanged.
Wherein the falling speed of the boost control signal is controlled by the start time, and the rising speed of the boost control signal is controlled by the release time.
And S5022, generating a boost control signal in a switch capacitor mode.
Referring to fig. 10, the boost-buck controller of the boost control generator receives the output of the boost comparator, and is in the through mode, sa, sc, sd is turned on when the system is started, and the boost control signal is equal to the reference voltage.
When Vint > Vth, the capacitor C1 needs to be discharged, sa is turned off, sb is turned off, sc is turned on first for each discharge period, the charge of C0 is discharged, sc is turned off, sd is turned on, C1 discharges the charge of C0, sd is turned off again, and the boost control signal Vco is continuously reduced in a cyclic manner, wherein the boost control signal Vco is specifically expressed as:
where Voc is the original control voltage, vco is the boost control signal, C1 is the first capacitance, C0 is the capacitance that discharges C1, and n is the number of discharges.
When Vint is smaller than Vtl, the capacitor C1 needs to be charged, sa is turned on, sb is turned off, each charging period, sc is turned on first, C0 is charged to a reference voltage, sc is turned off, sd is turned on, C0 charges C1, sd is turned off again, and the boost control signal Vco is continuously increased in a cyclic manner, wherein the boost control signal Vco is specifically expressed as:
wherein Vref is a reference voltage, vco is a boost control signal, voc is an original control voltage, C1 is a first capacitor, C0 is a capacitor for charging C1, and n is the number of times of charging.
When Vtl is less than or equal to Vint and less than or equal to Vth, the boost control signal remains unchanged.
Wherein the falling speed of the boost control signal is controlled by the start time, and the rising speed of the boost control signal is controlled by the release time.
Referring to fig. 11, in the present embodiment, when the input signal is small, the output power supply does not need to boost, and the output signal is boosted and then the power supply PVDD is boosted and stepped down according to the system requirement.
Referring to fig. 12, the boost comparator and the truncated comparator monitor the integrator output Vint, generate a boost control signal to control the power supply voltage, and simultaneously generate a gain control signal by comparing the integrator output Vint with the modulation triangular wave peak value, adjust the gain, avoid the output signal from being truncated, and reduce the distortion.
In summary, the invention compares the output signal of the integrator with the modulating triangular peak value to judge whether the output signal is truncated, generates the gain control signal to adjust the amplitude of the output signal, reduces the distortion of the output signal, and simultaneously monitors the output signal of the integrator to generate the boost control signal to control the boost voltage to meet the requirement of the output sound signal, so that the boost voltage is attached to the output signal as much as possible, the efficiency is improved, the working time is prolonged, and the power source PVDD is attached to the output signal as much as possible under the condition of effectively controlling the output distortion, thereby improving the overall efficiency of the work.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (18)
1. An audio device comprising a class D amplifier and a boost controller;
the class-D amplifier comprises an integrating filter, a triangular wave generator, a gain control component and a boost control component;
the integrating filter is used for outputting an integrator; the triangular wave generator is used for setting a boosting threshold comparison voltage and outputting a modulating triangular wave peak value; the gain control component is used for comparing the output of the integrator with the peak value of the modulated triangular wave and outputting a gain control signal so as to adjust the gain of an input signal and further adjust the amplitude of an output signal; the boost control component is configured to generate a boost control signal to change a power of the boost controller to power the class D amplifier.
2. The audio device of claim 1, wherein the gain control component comprises a truncated comparator, a gain controller, and a variable gain amplifier;
the truncated comparator is used for sampling the output of the integrator and comparing the output with the modulation triangular wave peak value, and sending out a gain control signal when the output of the integrator exceeds the modulation triangular wave peak value;
the gain control signal controls a gain controller to adjust the variable gain amplifier, thereby adjusting the amplitude of the output signal.
3. The audio device of claim 2, wherein the gain controller is configured to gradually attenuate a gain of an input signal according to a start-up time of the gain controller, reducing an amplitude of the output signal; and gradually recovering the gain of the input signal according to the release time of the gain controller, and increasing the amplitude of the output signal.
4. The audio device of claim 1, wherein the boost control component comprises a boost comparator for sampling the integrator output and comparing with the boost threshold comparison voltage, and a boost control signal generator for controlling the boost control signal generator to generate the boost control signal that alters the power supplied by the boost controller to the class D amplifier.
5. A power supply control method with gain control, employing an audio device as claimed in any one of claims 1 to 4, comprising:
comparing the output of the integrator with the modulating triangular wave peak value, and judging whether the output signal is truncated or not;
if the output signal is truncated, sending out a gain control signal, and gradually attenuating the gain of the input signal to reduce the amplitude of the output signal;
when the output signal is not truncated, sending out the gain control signal, and gradually recovering the gain of the input signal to increase the amplitude of the output signal;
setting a high threshold comparison voltage and a low threshold comparison voltage, comparing the integrator output with the high threshold comparison voltage and the low threshold comparison voltage to generate the boost control signal;
and changing the power of the boosting controller for supplying power to the class-D amplifier through the boosting control signal.
6. The power supply control method with gain control according to claim 5, wherein said judging whether or not the output signal has a truncated shape comprises: and if the output of the integrator exceeds the modulation triangular wave peak value, judging that the output signal is truncated.
7. The power supply control method with gain control according to claim 5, wherein the gain of the input signal is gradually attenuated according to the start-up time of the gain controller, and the gain of the input signal is gradually restored according to the release time of the gain controller.
8. The power supply control method with gain control of claim 5, wherein said comparing said integrator output to said high threshold comparison voltage and said low threshold comparison voltage comprises: when the integrator output is higher than the high threshold comparison voltage, the boost control signal controls a power supply to boost; the boost control signal controlling the power supply to decrease when the integrator output is below the low threshold comparison voltage; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
9. The power supply control method with gain control of claim 5, wherein the boost control signal changing the power supplied by the boost controller to the class D amplifier comprises: the boost control signal is connected with an error amplifier of the boost controller, and the higher the boost control signal is, the higher the power supply is; and when the power supply is smaller than or equal to the input voltage, the boost controller enters a through mode, and the power supply is equal to the input voltage.
10. The power supply control method with gain control of claim 9, wherein generating the boost control signal comprises: the boost control signal is generated by means of resistive voltage division.
11. The power supply control method with gain control according to claim 10, wherein when the integrator output is higher than the high threshold comparison voltage, a reversible counter counts up, a switch control signal valid bit is gradually increased, and the boost control signal is gradually increased; when the integrator output is lower than the low threshold comparison voltage, the reversible counter counts down, the switch control signal valid bit is gradually reduced, and the boost control signal is gradually reduced; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
12. The power supply control method with gain control of claim 9, wherein generating the boost control signal further comprises: the boost control signal is generated by means of a switch and a capacitor.
13. The power supply control method with gain control of claim 12, wherein when the integrator output is higher than the high threshold comparison voltage, charging a first one of the capacitances continuously increases the boost control signal; discharging the first capacitor when the integrator output is lower than the low threshold comparison voltage, and continuously reducing the boost control signal; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
14. The power supply control method with gain control of claim 5, wherein the boost control signal changing the power of the boost controller to power the class D amplifier further comprises: the boost control signal is connected with a voltage division network of the power supply through a resistor.
15. The power supply control method with gain control of claim 14, wherein generating the boost control signal comprises: the boost control signal is generated by means of resistive voltage division.
16. The power supply control method with gain control of claim 15, wherein when the integrator output is higher than the high threshold comparison voltage, a reversible counter counts up, a switch control signal valid bit is gradually increased, and the boost control signal is gradually decreased; when the integrator output is lower than the low threshold comparison voltage, the reversible counter counts down, the switch control signal valid bit is gradually reduced, and the boost control signal is gradually increased; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
17. The power supply control method with gain control of claim 14, wherein generating the boost control signal further comprises: the boost control signal is generated by means of a switch and a capacitor.
18. The power supply control method with gain control of claim 17, wherein when the integrator output is higher than the high threshold comparison voltage, discharging a first one of the capacitors continuously decreases the boost control signal; charging the first capacitor when the integrator output is lower than the low threshold comparison voltage, and continuously raising the boost control signal; the boost control signal remains unchanged when the integrator output is not below the low threshold comparison voltage and not above the high threshold comparison voltage.
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