Abstract: An adaptive DC-DC boost converter arrangement and an electronic circuit including such an arrangement are provided. The arrangement includes a circuit board with a plurality of electronic components mounted thereon, implementing an adaptive DC-DC boost converter circuit and a boost decoupling capacitor. The adaptive DC-DC boost converter circuit comprises a DC-DC boost converter having a converter set value input, a boost supply input, and a boost voltage output, and an adaptive DC-DC boost control unit having a control input and a control output. An acoustical noise suppression filter is present having a filter input connected to the control output of the adaptive DC-DC boost control unit and a filter output connected to the converter set value input of the DC-DC boost converter.

Abstract: An adaptive DC-DC boost converter arrangement and an electronic circuit including such an arrangement are provided. The arrangement includes a circuit board with a plurality of electronic components mounted thereon, implementing an adaptive DC-DC boost converter circuit and a boost decoupling capacitor. The adaptive DC-DC boost converter circuit comprises a DC-DC boost converter having a converter set value input, a boost supply input, and a boost voltage output, and an adaptive DC-DC boost control unit having a control input and a control output. An acoustical noise suppression filter is present having a filter input connected to the control output of the adaptive DC-DC boost control unit and a filter output connected to the converter set value input of the DC-DC boost converter.

Abstract: A driver circuit arrangement for driving a load and a differential drive arrangement thereof are provided. The driver circuit arrangement employs a dual feedback configuration with a feedback resistor and a current sensor feedback arrangement. The current sensor feedback arrangement provides a current feedback path from the amplifier output to the amplifier input, and has a current sensor resistor connected in an output current path of the driver circuit arrangement. A current feedback amplifier is present connected to the current sensor resistor and to the amplifier input.

Abstract: An adaptive DC-DC boost converter arrangement and an electronic circuit including such an arrangement are provided. The arrangement includes a circuit board with a plurality of electronic components mounted thereon, implementing an adaptive DC-DC boost converter circuit and a boost decoupling capacitor. The adaptive DC-DC boost converter circuit comprises a DC-DC boost converter having a converter set value input, a boost supply input, and a boost voltage output, and an adaptive DC-DC boost control unit having a control input and a control output. An acoustical noise suppression filter is present having a filter input connected to the control output of the adaptive DC-DC boost control unit and a filter output connected to the converter set value input of the DC-DC boost converter.

Abstract: An audio amplifier system is described comprising: a variable gain audio processor for processing digital audio signal, a digital to analog converter coupled to the audio processor, and configured to receive the processed digital audio signal, a variable gain amplifier having an input coupled to the output of the digital to analog converter and operably connected to a power supply, a controller coupled to the variable gain audio processor and the variable gain amplifier and configured to switch the audio amplifier system between a first operating mode having a first power supply voltage value and a second operating mode having a second higher power supply voltage value; wherein the controller is operable in the first operating mode to set the audio amplifier system gain to a desired gain value and in the second operating mode to maintain the desired gain value.

Abstract: An audio amplifier system is described comprising: a variable gain audio processor for processing digital audio signal, a digital to analog converter coupled to the audio processor, and configured to receive the processed digital audio signal, a variable gain amplifier having an input coupled to the output of the digital to analog converter and operably connected to a power supply, a controller coupled to the variable gain audio processor and the variable gain amplifier and configured to switch the audio amplifier system between a first operating mode having a first power supply voltage value and a second operating mode having a second higher power supply voltage value; wherein the controller is operable in the first operating mode to set the audio amplifier system gain to a desired gain value and in the second operating mode to maintain the desired gain value.

Abstract: A microphone circuit has a clip detection circuit which detects when an analogue to digital converter output has reached a threshold. A variable attenuator is controlled based on the clip detection circuit output. The feedback is thus based on the ADC output level, and the processing of this signal can be implemented without requiring baseband processing of the signal—it can simply be based on a state of the ADC output. An overrule function is also provided so that the clip detection AGC control can be inhibited or controlled differently.

Abstract: A true ground amplifier circuit in which a voltage sensor senses the output voltage and generates a binary output which indicates whether the output is above or below a threshold. A variable gain feedback system generates a feedback signal for combination with the digital input, thereby to provide offset cancellation. The variable gain is reduced over time to provide offset cancellation during an initial period of time of operation of the amplifier circuit. This provides offset cancellation during a start-up period, for example.

Abstract: An analog to digital converter comprises an input terminal configured to receive an analog input signal and an output terminal configured to provide an output digital signal.

Abstract: An analogue to digital converter comprises an input terminal configured to receive an analogue input signal and an output terminal configured to provide an output digital signal.

Abstract: A true ground amplifier circuit in which a voltage sensor senses the output voltage and generates a binary output which indicates whether the output is above or below a threshold. A variable gain feedback system generates a feedback signal for combination with the digital input, thereby to provide offset cancellation. The variable gain is reduced over time to provide offset cancellation during an initial period of time of operation of the amplifier circuit. This provides offset cancellation during a start-up period, for example.

Abstract: An amplifier is disclosed, wherein the output stage is split between a primary output stage and a secondary stage. To minimize or eliminate any audible plop when the amplifier is switched on, the primary stage is connected, and the second stage is gradually connected using a switch. The gradual connection can be by means of varying the pulse-density of a pulse wave modulation on the switch, from fully open (0% pulse-density) to fully closed (100%). The inverse process can minimize or eliminate plop during switch-off. Separate feedback loops are switchable, from the primary and secondary stages; in a DC-coupled embodiment, the feedback loop from the secondary stage may include DC-offset cancelling circuitry, to both reduce or eliminate the plop and avoid and DC-offset current through the speaker.

Abstract: A microphone circuit has a clip detection circuit which detects when an analogue to digital converter output has reached a threshold. A variable attenuator is controlled based on the clip detection circuit output. The feedback is thus based on the ADC output level, and the processing of this signal can be implemented without requiring baseband processing of the signal—it can simply be based on a state of the ADC output. An overrule function is also provided so that the clip detection AGC control can be inhibited or controlled differently.

Abstract: A class H amplifier circuit includes a Buck converter 20 and a charge pump 30 which are used to generate voltages which are used in turn to power an output driver 10. A feedback path 36 controls the loop. The circuit is particularly suitable as a high efficiency circuit for driving headphones or loudspeakers.

Abstract: A circuit for monitoring capacitive signal sources, and particularly detecting changes in capacitance of a variable capacitor, comprises the capacitive signal source and a differential analogue to digital converter. A voltage source provides a DC voltage to a first terminal of the differential analogue to digital converter, and the capacitive signal source is connected to the other terminal of the differential analogue to digital converter. A feedback path low pass filters the output of the differential analogue to digital converter to derive a DC offset value and couples the DC offset value to the other terminal of the differential analogue to digital converter.

Abstract: An amplifier is disclosed, wherein the output stage is split between a primary output stage and a secondary stage. To minimise or eliminate any audible plop when the amplifier is switched on, the primary stage is connected, and the second stage is gradually connected using a switch. The gradual connection can be by means of varying the pulse-density of a pulse wave modulation on the switch, from fully open (0% pulse-density) to fully closed (100%). The inverse process can minimise or eliminate plop during switch-off. Separate feedback loops are switchable, from the primary and secondary stages; in a DC-coupled embodiment, the feedback loop from the secondary stage may include DC-offset cancelling circuitry, to both reduce or eliminate the plop and avoid and DC-offset current through the speaker.

Abstract: A class H amplifier circuit includes a Buck converter 20 and a charge pump 30 which are used to generate voltages which are used in turn to power an output driver 10. A feedback path 36 controls the loop. The circuit is particularly suitable as a high efficiency circuit for driving headphones or loudspeakers.

Abstract: The invention relates to a Sigma Delta A/D converter (2) for generating a N-bits digital output signal (4) on the basis of an analogue input signal (6), comprising a control loop which comprises a quantizer (8) comprising at least a comparator (24.1, 24.2) for generating the N-bits digital output signal (4) and a D/A converter (10) in a first feedback loop (12) of the control loop for generating an analogue version (14) of the N-bits digital output signal (4) on the basis of the N-bits digital output signal (4), wherein the quantizer (8) also comprises an Up-Down counter (26) which is coupled to the comparator (24.1, 24.2), wherein the D/A converter (10) is coupled to the comparator (24.1, 24.2) in a second feedback loop (27) of the control loop.

Abstract: To switch a switch of an audio source for example the problem exists that switching noise can occur.