An amplifier and a method of outputting a waveform of a music signal capable of outputting a waveform of a music signal exceeding a power supply voltage is provided. An amplifier includes a power supply, an input terminal for a music signal, an amplifying circuit which amplifies the music signal using the power supply, and a jumping-up circuit which is connected to an output end of the amplifying circuit and outputs a waveform exceeding a voltage value of the power supply.

Differential control circuitry configured to control the operation of a power converter. The control circuitry of this disclosure is configured to receive two differential feedback signals from a fully differential amplifier. The amplifier receives an output voltage (Vout) from the switched mode power supply as well as a reference voltage (Vref). When Vout is less than Vref, the control circuitry may output a pulse width modulation (PWM) control signal to the switched mode power supply with a duty cycle of the PWM control signal based on a relative difference between a positive difference voltage and a negative difference voltage. When Vout is greater than Vref, the control circuitry may output a pulse frequency modulation (PFM) control signal to the switched mode power supply with a switching time of the PFM control signal based on a relative difference between the positive difference voltage and the negative difference voltage.

A shaper circuit includes a first amplifier including an input and an output, the input being configured to receive an input signal, which includes one or more current pulses, a feedback component coupled to the output and to the input of the first amplifier thereby forming a feedback loop of the first amplifier, and an RC component coupled to the output of the first amplifier and to a reference potential terminal. Therein the shaper circuit is configured to provide an output signal as a function of the input signal, the output signal including one or more voltage pulses, and the RC component is configured to largely cancel a low frequency pole of the feedback loop of the first amplifier.

Differential control circuitry configured to control the operation of a power converter. The control circuitry of this disclosure is configured to receive two differential feedback signals from a fully differential amplifier. The amplifier receives an output voltage (Vout) from the switched mode power supply as well as a reference voltage (Vref). When Vout is less than Vref, the control circuitry may output a pulse width modulation (PWM) control signal to the switched mode power supply with a duty cycle of the PWM control signal based on a relative difference between a positive difference voltage and a negative difference voltage. When Vout is greater than Vref, the control circuitry may output a pulse frequency modulation (PFM) control signal to the switched mode power supply with a switching time of the PFM control signal based on a relative difference between the positive difference voltage and the negative difference voltage.

An amplifier and a method of outputting a waveform of a music signal capable of outputting a waveform of a music signal exceeding a power supply voltage is provided. An amplifier includes a power supply, an input terminal for a music signal, an amplifying circuit which amplifies the music signal using the power supply, and a jumping-up circuit which is connected to an output end of the amplifying circuit and outputs a waveform exceeding a voltage value of the power supply.

An error amplifier including a differential pair circuit, a resistive device, a low voltage capacitor, and a protection device. The differential pair circuit is coupled between an upper supply node and a lower supply node with first and second intermediate nodes and is responsive to a difference between a reference voltage and a feedback voltage for driving a control voltage developed on the second intermediate node. The resistive device is coupled between the second intermediate node and a low voltage node, and the low voltage capacitor and the protection device are coupled between the low voltage node and the lower supply node. The protection device is dynamically controlled by the first intermediate node to prevent the low voltage node from exceeding a predetermined maximum level. The protection device may be a transistor having size parameters based on voltage characteristics of the first intermediate node during expected operating conditions.

A two-stage circuit includes a differential-to-single-ended first stage with a differential pair of transistors. The first stage includes a current mirror including a diode-connected transistor having an RC circuit coupled to a drain of the diode-connected transistor. The current mirror is configured to mirror a power supply noise current conducted by the RC circuit through a first stage output terminal to a gate of an output transistor in a second stage of the two-stage circuit.