Abstract: In one embodiment the present invention includes a method for starting up a class D amplifier. The method comprises increasing, gating, and driving. The increasing includes increasing a duty cycle of a pulse train from a first duty cycle to a second duty cycle. The gating includes gating a signal based on the increasing of the duty cycle. The gating results in a gated signal. The driving includes driving an output signal from the gated signal to charge an output capacitor. The output capacitor is coupled to a speaker. The increasing of the duty cycle contributes to the charging of the output capacitor such that switching sounds detectable by the human ear are reduced.

Abstract: In one embodiment the present invention includes a switching circuit. The circuit comprises a first transistor, a second transistor, and a boost circuit. The first transistor couples a first power source to a first intermediate node during a first phase of operation and the second transistor couples a second intermediate node to the first intermediate node during a second phase of operation. The boost circuit is coupled to the second intermediate node and provides a second power source by a transferring of energy from the first power source. The transferring of energy includes an inductor receiving energy from the first power source during the first phase of operation and providing a portion of said energy to the boost circuit during the second phase of operation. The boost circuit provides a biasing to enable deactivation of the second transistor during the first phase of operation.

Abstract: In one embodiment, the present invention includes a charge pump circuit. The charge pump circuit comprises a plurality of terminals, a plurality of switches for selectively coupling the plurality of terminals, and a control circuit. A first input terminal receives a first reference voltage and a second input terminal receives a second reference voltage. First, second, third, and fourth flying capacitor terminals and the first and second input terminals are selectively coupled together in different configurations. The control circuit selects the switches to actuate according to a cycling of at least three phases of configuration. The cycling shifts the first and second reference voltages to provide dual power supply rails.

Abstract: In one embodiment the present invention includes a DC to DC converter device which includes an electronic circuit. The electronic circuit comprises a first comparator, a second comparator, a first switch, a first latch, and a current sensor. The inductor current includes a peak current value and a valley current value. The first comparator detects the peak current value and resets the first latch which opens the first switch. The second comparator detects the valley current value and sets the first latch which closes the first switch. The current sensor is coupled to sense an inductor current flowing through an output load, and is coupled to provide a sense voltage to the first and second comparators. In this manner, the electronic circuit provides DC to DC conversion with current control.

Abstract: In one embodiment the present invention includes a method for starting up a class D amplifier. The method comprises increasing, gating, and driving. The increasing includes increasing a duty cycle of a pulse train from a first duty cycle to a second duty cycle. The gating includes gating a signal based on the increasing of the duty cycle. The gating results in a gated signal. The driving includes driving an output signal from the gated signal to charge an output capacitor. The output capacitor is coupled to a speaker. The increasing of the duty cycle contributes to the charging of the output capacitor such that switching sounds detectable by the human ear are reduced.

Abstract: Embodiments of the present invention include systems and methods of control using a single wire. The systems and methods presented allow sending or receiving commands and data through a single wire. In one embodiment, commands and data are received by the control system through a single terminal. In another embodiment, commands and data are received and transmitted from the control system through a single terminal.

Abstract: Embodiments of the present invention include circuits and methods for electrical current control. In one embodiment, a regulator provides power to the anode end of a set of LED strings. A current setting circuit derives its current from a current reference and generates multiple matching currents that drive the low side (cathode end) of the set of LED strings. The current setting circuit also contains a feedback signal to the regulator that helps maintain a desired voltage level to the anode end of the LED strings. This embodiment is designed to be expandable and drive any number of LED strings. The present invention may be implemented with a high or low side driver scheme to drive the current. Also, the present invention may be implemented with bipolar, nmos, pmos, or any device that operates as a transistor.

Abstract: Embodiments of the present invention include switching amplifier circuits and methods. In one embodiment, the present invention includes an low distortion method of driving a switching amplifier comprising generating a first pulse width modulated signal on a first terminal, generating a second pulse width modulated signal on a second terminal, and delaying one of the first or second signals. In one embodiment, the modulated signals and delay result in pulse trains near zero crossings to reduce crossover distortion.

Abstract: Embodiments of the present invention include a method of starting a boost regulator comprising during an initial phase beginning when the boost regulator is powered off, coupling a first current from the input node to the output node to increase a voltage on the capacitor to a first voltage level, during a second phase following the first phase, switching the PMOS transistor and the NMOS transistor, during a third phase following the second phase, turning said PMOS off and switching said NMOS transistor, and during a fourth phase, synchronously switching the PMOS transistor and NMOS transistor.

Abstract: Embodiments of the present invention include circuits and methods for electrical current control. In one embodiment, a regulator provides power to the anode end of a set of LED strings. A current setting circuit derives its current from a current reference and generates multiple matching currents that drive the low side (cathode end) of the set of LED strings. The current setting circuit also contains a feedback signal to the regulator that helps maintain a desired voltage level to the anode end of the LED strings. This embodiment is designed to be expandable and drive any number of LED strings. The present invention may be implemented with a high or low side driver scheme to drive the current. Also, the present invention may be implemented with bipolar, nmos, pmos, or any device that operates as a transistor.

Abstract: Embodiments of the present invention include systems and methods of control using a single wire. The systems and methods presented allow sending or receiving commands and data through a single wire. In one embodiment, commands and data are received by the control system through a single terminal. In another embodiment, commands and data are received and transmitted from the control system through a single terminal.

Abstract: Embodiments of the present invention include systems and methods of driving an electroluminescent lamp. In one embodiment, the electroluminescent lamp is driven to a first threshold during a first time period and then driven to successive voltages between the threshold and a maximum voltage during successive time. This method of driving the lamp waveshapes the lamp voltage signal. In one example, the thresholds are set to minimize audible noise from the electroluminescent lamp due to the piezoelectric effect.

Abstract: Embodiments of the present invention include systems and methods of driving an electroluminescent lamp. In one embodiment, the electroluminescent lamp is driven to a first threshold during a first time period and then driven to successive voltages between the threshold and a maximum voltage during successive time. This method of driving the lamp waveshapes the lamp voltage signal. In one example, the thresholds are set to minimize audible noise from the electroluminescent lamp due to the piezoelectric effect.

Abstract: Embodiments of the present invention include switching amplifier circuits and methods. In one embodiment, the present invention includes an audio amplification method comprising modulating an audio input signal to produce a first modulated signal and a second modulated signal, amplifying the first modulated signal to generate an amplified first modulated signal at a first output terminal of an amplifier, and amplifying the second modulated signal to generate an amplified second modulated signal at a second output terminal of the amplifier, wherein the first output terminal of the amplifier is constant when the second output terminal of the amplifier is switching, and wherein the second output terminal of the amplifier is constant when the first output terminal of the amplifier is switching.

Abstract: In one embodiment, the present invention includes a circuit comprising an amplifier having an input terminal, an output terminal, a positive supply voltage, and a negative supply voltage. The amplifier is configured to have a first gain. A variable feedback circuit is coupled between the input terminal and the output terminal. The difference between the voltage on the output terminal and input terminal is received by the variable feedback circuit, which changes the gain of the circuit and reduces distortion.