Abstract: A method of detecting a state of charge of a battery, can include: obtaining an open circuit voltage in a present cycle according to an open circuit voltage of a previous cycle, a battery internal resistance of the previous cycle, and a battery capacitance of the previous cycle, where the battery internal resistance and the battery capacitance are updated according to the state of charge of the battery; and determining the state of charge of the battery according to the open circuit voltage in the present cycle.

Abstract: A loudspeaker diaphragm state estimation method includes: adjusting a weight value of a diaphragm displacement model by adaptive filtering until an error between an estimated value of a driving voltage of a loudspeaker and a measured value of the driving voltage is less than a predetermined threshold; estimating a diaphragm relative displacement of the loudspeaker according to the diaphragm displacement model corresponding to a final determined weight value; determining a diaphragm relative speed at a next moment based on an input current, a product value of a vector determined by an estimated value of a diaphragm relative speed and an estimated value of a diaphragm relative displacement, and a weight value vector obtained at a present moment; and determining an estimated value of the driving voltage using the estimated value of the diaphragm relative speed, the input current, and a DC impedance of the loudspeaker at the present moment.

Abstract: A battery balance circuit configured for a battery apparatus having two batteries coupled in series, can include: first and second capacitors respectively coupled to two terminals of the two batteries; first and second switching circuits respectively coupled to the two terminals of the two batteries, where the first and second switching circuits are configured to control charging or discharging of each of the two batteries; a third capacitor coupled between the first and second switching circuits, where the third capacitor is configured to store or release energy in order to balance battery levels between the two batteries; and parasitic inductors, where the third capacitor and the parasitic inductors are configured to resonate, and the first and second switching circuits are configured to operate at a resonance frequency.

Abstract: A speaker driving apparatus can include: a sound pressure feedback unit configured to generate an electrical signal indicative of a sound pressure of a loudspeaker; a compensation unit configured to compensate an input audio signal according to the electrical signal indicative of the sound pressure of the loudspeaker to generate a compensated audio signal, where the sound pressure of the loudspeaker is linearly related to the input audio signal; and an amplification unit configured to amplify the compensated audio signal in order to drive the loudspeaker.

Abstract: A method of balancing battery power can include: determining batteries to be balanced and directions of balance currents according to charge and discharge states and power states of the batteries, where each of the power states includes a state of charge, a remaining capacity, and a capacity to be charged; determining a reference of the balance current based on controlling temperatures of the batteries to be balanced to be lower than a temperature threshold when the SOCs of the batteries to be balanced are lower than a predetermined threshold; and balancing power of the batteries to be balanced according to the directions of the balance currents and the reference.

Abstract: A loudspeaker diaphragm state estimation method includes: adjusting a weight value of a diaphragm displacement model by adaptive filtering until an error between an estimated value of a driving voltage of a loudspeaker and a measured value of the driving voltage is less than a predetermined threshold; estimating a diaphragm relative displacement of the loudspeaker according to the diaphragm displacement model corresponding to a final determined weight value; determining a diaphragm relative speed at a next moment based on an input current, a product value of a vector determined by an estimated value of a diaphragm relative speed and an estimated value of a diaphragm relative displacement, and a weight value vector obtained at a present moment; and determining an estimated value of the driving voltage using the estimated value of the diaphragm relative speed, the input current, and a DC impedance of the loudspeaker at the present moment.

Abstract: A loudspeaker diaphragm state estimation method includes: adjusting a weight value of a diaphragm displacement model by adaptive filtering until an error between an estimated value of a driving voltage of a loudspeaker and a measured value of the driving voltage is less than a predetermined threshold; estimating a diaphragm relative displacement of the loudspeaker according to the diaphragm displacement model corresponding to a final determined weight value; determining a diaphragm relative speed at a next moment based on an input current, a product value of a vector determined by an estimated value of a diaphragm relative speed and an estimated value of a diaphragm relative displacement, and a weight value vector obtained at a present moment; and determining an estimated value of the driving voltage using the estimated value of the diaphragm relative speed, the input current, and a DC impedance of the loudspeaker at the present moment.

Abstract: A loudspeaker diaphragm state estimation method includes: adjusting a weight value of a diaphragm displacement model by adaptive filtering until an error between an estimated value of a driving voltage of a loudspeaker and a measured value of the driving voltage is less than a predetermined threshold; estimating a diaphragm relative displacement of the loudspeaker according to the diaphragm displacement model corresponding to a final determined weight value; determining a diaphragm relative speed at a next moment based on an input current, a product value of a vector determined by an estimated value of a diaphragm relative speed and an estimated value of a diaphragm relative displacement, and a weight value vector obtained at a present moment; and determining an estimated value of the driving voltage using the estimated value of the diaphragm relative speed, the input current, and a DC impedance of the loudspeaker at the present moment.

Abstract: A speaker driving apparatus can include: a sound pressure feedback unit configured to generate an electrical signal indicative of a sound pressure of a loudspeaker; a compensation unit configured to compensate an input audio signal according to the electrical signal indicative of the sound pressure of the loudspeaker to generate a compensated audio signal, where the sound pressure of the loudspeaker is linearly related to the input audio signal; and an amplification unit configured to amplify the compensated audio signal in order to drive the loudspeaker.

Abstract: The present disclosure relates to a class-D audio amplifier. When the class-D audio amplifier is powered on, an auxiliary power amplifier and an auxiliary feedback circuit constitute an auxiliary close loop so that a control loop is established in advance. The auxiliary close loop is disconnected after various circuit modules reach their steady operation points, and the class-D audio amplifier operates at a normal state. A soft start circuit is provided for suppressing noise which occurs when the class-D audio amplifier is powered on. Thus, the class-D audio amplifier suppresses POP noise at an output terminal when the class-D audio amplifier is powered on.

Abstract: A method of detecting a state of charge of a battery, can include: obtaining an open circuit voltage in a present cycle according to an open circuit voltage of a previous cycle, a battery internal resistance of the previous cycle, and a battery capacitance of the previous cycle, where the battery internal resistance and the battery capacitance are updated according to the state of charge of the battery; and determining the state of charge of the battery according to the open circuit voltage in the present cycle.

Abstract: A DC impedance detection circuit can include: an integration time generation circuit configured to generate an integration time signal in accordance with a current flowing through a speaker, where the current of a speaker at a beginning time of each active time interval of the integration time signal is the same as that at an ending time of the active time interval; a current integration circuit configured to integrate the current of the speaker in the active time interval, and to generate a current integration signal; a voltage integration circuit configured to integrate a voltage of the speaker in the active time interval, and to generate a voltage integration signal; and where a ratio between the voltage integration signal and the current integration signal is configured as a DC impedance of the speaker in the active time interval.

Abstract: Disclosed herein are various battery power measurement devices, methods, and related apparatuses. In one embodiment, a method of measuring a battery power can include: (i) detecting a voltage and a temperature at an output terminal of a battery; (ii) obtaining a first correction coefficient based on a battery open-circuit voltage at a previous sample time; (iii) obtaining a second correction coefficient based on the battery temperature; (iv) calculating a real-time battery open-circuit voltage by using the voltage at the output terminal of the battery, the first and second correction coefficients, the battery open-circuit voltage at the previous sample time, and a time interval between the previous sample time and a present sample time; and (v) converting the real-time battery open-circuit voltage into a battery power measurement for display.

Abstract: A method of balancing battery power can include: determining batteries to be balanced and directions of balance currents according to charge and discharge states and power states of the batteries, where each of the power states includes a state of charge, a remaining capacity, and a capacity to be charged; determining a reference of the balance current based on controlling temperatures of the batteries to be balanced to be lower than a temperature threshold when the SOCs of the batteries to be balanced are lower than a predetermined threshold; and balancing power of the batteries to be balanced according to the directions of the balance currents and the reference.

Abstract: A battery balance circuit configured for a battery apparatus having two batteries coupled in series, can include: first and second capacitors respectively coupled to two terminals of the two batteries; first and second switching circuits respectively coupled to the two terminals of the two batteries, where the first and second switching circuits are configured to control charging or discharging of each of the two batteries; a third capacitor coupled between the first and second switching circuits, where the third capacitor is configured to store or release energy in order to balance battery levels between the two batteries; and parasitic inductors, where the third capacitor and the parasitic inductors are configured to resonate, and the first and second switching circuits are configured to operate at a resonance frequency.

Abstract: The present disclosure relates to a class-D audio amplifier. When the system is powered on, an auxiliary power amplifier and an auxiliary feedback circuit constitute an auxiliary close loop so that a control loop is established in advance. The auxiliary close loop is disconnected after various circuit modules reach their steady operation points, and the system operates at a normal state. A soft start circuit is provided for suppressing noise which occurs when the system is powered on. Thus, the class-D audio amplifier suppresses POP noise at an output terminal when the system is powered on.

Abstract: A DC impedance detection circuit can include: an integration time generation circuit configured to generate an integration time signal in accordance with a current flowing through a speaker, where the current of a speaker at a beginning time of each active time interval of the integration time signal is the same as that at an ending time of the active time interval; a current integration circuit configured to integrate the current of the speaker in the active time interval, and to generate a current integration signal; a voltage integration circuit configured to integrate a voltage of the speaker in the active time interval, and to generate a voltage integration signal; and where a ratio between the voltage integration signal and the current integration signal is configured as a DC impedance of the speaker in the active time interval.

Abstract: Disclosed herein are various battery power measurement devices, methods, and related apparatuses. In one embodiment, a method of measuring a battery power can include: (i) detecting a voltage and a temperature at an output terminal of a battery; (ii) obtaining a first correction coefficient based on a battery open-circuit voltage at a previous sample time; (iii) obtaining a second correction coefficient based on the battery temperature; (iv) calculating a real-time battery open-circuit voltage by using the voltage at the output terminal of the battery, the first and second correction coefficients, the battery open-circuit voltage at the previous sample time, and a time interval between the previous sample time and a present sample time; and (v) converting the real-time battery open-circuit voltage into a battery power measurement for display.