Abstract: Circuitry for detecting a capacitive load coupled between a first node and a second node, the circuitry comprising: drive circuitry for applying a first voltage to a first node over a first time period; processing circuitry configured to: measure a second voltage at the first node; and determine that the load is a capacitive load based on the second voltage.

Abstract: Circuitry for detecting a capacitive load coupled between a first node and a second node, the circuitry comprising: drive circuitry for applying a first voltage to a first node over a first time period; processing circuitry configured to: measure a second voltage at the first node; and determine that the load is a capacitive load based on the second voltage.

Abstract: This application relates to methods and apparatus for voltage control, and in particular to maintain safe voltages for components of audio driving circuits that are operable in a high voltage mode. An audio driving circuit (100) may include a power supply module (106) and may be operable such that, in use, a voltage magnitude at a source terminal of at least a first transistor (306, 309, 603, 605) of the audio driving circuit can exceed its gate-source voltage tolerance. A voltage generator (111 P) is configured to output a first intermediate voltage (VSAFEP) to an intermediate voltage path for use as a gate control voltage for at least the first transistor, to maintain its gate-source voltage below tolerance. An intermediate path voltage clamp (114P) is provided for selectively clamping the intermediate voltage path to a voltage level, so as to maintain the magnitude of the gate-source voltage of the first transistor below tolerance.

Abstract: This application relates to methods and apparatus for voltage control, and in particular to maintain safe voltages for components of audio driving circuits that are operable in a high voltage mode. An audio driving circuit (100) may include a power supply module (106) and may be operable such that, in use, a voltage magnitude at a source terminal of at least a first transistor (306, 309, 603, 605) of the audio driving circuit can exceed its gate-source voltage tolerance. A voltage generator (111 P) is configured to output a first intermediate voltage (VSAFEP) to an intermediate voltage path for use as a gate control voltage for at least the first transistor, to maintain its gate-source voltage below tolerance. An intermediate path voltage clamp (114P) is provided for selectively clamping the intermediate voltage path to a voltage level, so as to maintain the magnitude of the gate-source voltage of the first transistor below tolerance.

Abstract: This application relates to switch arrangements, in particular switch arrangements suitable for switchable connecting nodes of audio driving circuitry (100) that may, in use, experience a signal swing depending on an output audio driving signal (VD). A switch arrangement (300) comprises first and second transistors (301 and 302) of the same polarity type connected in series between the first and second nodes, with a third transistor (303) connected between a defined voltage (VS) and an intermediate node (N3) between the first and second transistors. The first transistor (301) has a drain connection to the first node (N1) and a source connection to the intermediate node (N3). The second transistor (302) has a drain connection to the second node (N2) and a source connection to the intermediate node (N3).

Abstract: This application relates to methods and apparatus for voltage control, and in particular to maintain safe voltages for components of audio driving circuits that are operable in a high voltage mode. An audio driving circuit (100) may include a power supply module (106) and may be operable such that, in use, a voltage magnitude at a source terminal of at least a first transistor (306, 309, 603, 605) of the audio driving circuit can exceed its gate-source voltage tolerance. A voltage generator (111P) is configured to output a first intermediate voltage (VSAFEP) to an intermediate voltage path for use as a gate control voltage for at least the first transistor, to maintain its gate-source voltage below tolerance. An intermediate path voltage clamp (114P) is provided for selectively clamping the intermediate voltage path to a voltage level, so as to maintain the magnitude of the gate-source voltage of the first transistor below tolerance.

Abstract: This application relates to switch arrangements, in particular switch arrangements suitable for switchable connecting nodes of audio driving circuitry (100) that may, in use, experience a signal swing depending on an output audio driving signal (VD). A switch arrangement (300) comprises first and second transistors (301 and 302) of the same polarity type connected in series between the first and second nodes, with a third transistor (303) connected between a defined voltage (VS) and an intermediate node (N3) between the first and second transistors. The first transistor (301) has a drain connection to the first node (N1) and a source connection to the intermediate node (N3). The second transistor (302) has a drain connection to the second node (N2) and a source connection to the intermediate node (N3).

Abstract: This application describes methods and apparatus for selectively clamping a signal path (106) for an analog audio signal to a clamp voltage, e.g. ground. Voltage clamping circuitry (200) is disclosed having a first switching device (201) in series with a second switching device (202) between a node of the signal path and the clamp voltage. The clamping circuitry is configured to be operable in: a first state where the first and second switching devices are both on to electrically connect the signal path to the clamp voltage; and also a second state to electrically disconnect the signal path from the clamp voltage. In the second state one of the first and second switching devices is configured to block conduction when the voltage at said node of the signal path is positive and the other switching device is configured to block conduction when the voltage at said node of the signal path is negative.

Abstract: This application describes methods and apparatus for selectively clamping a signal path (106) for an analogue audio signal to a clamp voltage, e.g. ground. Voltage clamping circuitry (200) is disclosed having a first switching device (201) in series with a second switching device (202) between a node of the signal path and the clamp voltage. The clamping circuitry is configured to be operable in: a first state where the first and second switching devices are both on to electrically connect the signal path to the clamp voltage; and also a second state to electrically disconnect the signal path from the clamp voltage. In the second state one of the first and second switching devices is configured to block conduction when the voltage at said node of the signal path is positive and the other switching device is configured to block conduction when the voltage at said node of the signal path is negative.

Abstract: A regulator structure includes a first differential amplifier having a first input coupled to a reference voltage node. A second differential amplifier has a first input coupled to the output of the first differential amplifier. A third differential amplifier has a first input coupled to the output of the first differential amplifier. A first pmos transistor has its gate coupled to the second differential amplifier output, and its drain coupled to a second input of each of the first and second differential amplifiers. A second pmos transistor has its gate coupled to the third differential amplifier output, and its drain configured to output a regulated voltage which is also a second input of the third differential amplifier. A circuit is configured to replicate the regulated voltage and couple the replicated regulated voltage to the drain of the first pmos transistor.

Abstract: A regulator structure includes a first differential amplifier having a first input coupled to a reference voltage node. A second differential amplifier has a first input coupled to the output of the first differential amplifier. A third differential amplifier has a first input coupled to the output of the first differential amplifier. A first pmos transistor has its gate coupled to the second differential amplifier output, and its drain coupled to a second input of each of the first and second differential amplifiers. A second pmos transistor has its gate coupled to the third differential amplifier output, and its drain configured to output a regulated voltage which is also a second input of the third differential amplifier. A circuit is configured to replicate the regulated voltage and couple the replicated regulated voltage to the drain of the first pmos transistor.

Abstract: A linear regulator with an N-type pass transistor includes an over-current protection circuit. A current sink is used as an indicator for an over-current condition and is coupled to the output of the linear regulator. The indicator is coupled to a feedback logic circuit that controls the current through the output load. The over-current protection circuit extensively uses N-type devices for various components including the output driver stage in the circuit. This results in reduced area for the over-current protection circuit.

Abstract: A linear regulator with an N-type pass transistor includes an over-current protection circuit. A current sink is used as an indicator for an over-current condition and is coupled to the output of the linear regulator. The indicator is coupled to a feedback logic circuit that controls the current through the output load. The over-current protection circuit extensively uses N-type devices for various components including the output driver stage in the circuit. This results in reduced area for the over-current protection circuit.