Abstract: A circuit, which is enabling the superpositioning of different audio signals such as voice, music or ringer signals in a audio output device is achieved. The individual superpositioning can be activated and performed by a combination of resistors and switches without the need of an additional mixing amplifier as in prior art. One common output stage is used for all the signals activated and superpositioned. The adjustment of the amplitude of the output signal, which can be used for the volume adjustment of a loudspeaker, is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier through a current-voltage conversion. Said current-voltage conversion is performed by a string of resistors activated by a string of correspondent switches. This circuit reduces the power consumption, the chip area required and the offset and improves the power supply rejection rate (PSSR).

Abstract: A circuit where the same amplifiers and the same volume adjustment circuitry are used for the ringer mode as well as for the audio mode of a mobile phone is achieved. The volume adjustment in the audio and ringer mode is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier used in a bridge circuit through a current-voltage conversion. This volume adjustment circuit avoids the high power dissipation of a volume control through pulse width modulation (PWM) and avoids the risk of over-and undershooting of the amplifier's output signal due to a high slew rate in combination with the inductance of the loudspeaker. The current-voltage conversion is performed by a series of resistors activated by a series of correspondent switches. High impedance current less sense paths are eliminating the parasitic effect of the resistance of low cost standard switches to adjust the volume of the loudspeaker in the audio and the ringer mode.

Abstract: A circuit where the same amplifiers and the same volume adjustment circuitry are used for the ringer mode as well as for the audio mode of a mobile phone is achieved. The volume adjustment in the audio and ringer mode is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier used in a bridge circuit through a current-voltage conversion. This volume adjustment circuit avoids the high power dissipation of a volume control through pulse width modulation (PWM) and avoids the risk of over -and undershooting of the amplifier's output signal due to a high slew rate in combination with the inductance of the loudspeaker. The current-voltage conversion is performed by a series of resistors activated by a series of correspondent switches. High impedance current less sense paths are eliminating the parasitic effect of the resistance of low cost standard switches to adjust the volume of the loudspeaker in the audio and the ringer mode.

Abstract: A circuit where the same amplifiers and the same volume adjustment circuitry are used for the ringer mode as well as for the audio mode of a mobile phone is achieved. The volume adjustment in the audio and ringer mode is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier used in a bridge circuit through a current-voltage conversion. This volume adjustment circuit avoids the high power dissipation of a volume control through pulse width modulation (PWM) and avoids the risk of over-and undershooting of the amplifier's output signal due to a high slew rate in combination with the inductance of the loudspeaker. The current-voltage conversion is performed by a series of resistors activated by a series of correspondent switches. High impedance current less sense paths are eliminating the parasitic effect of the resistance of low cost standard switches to adjust the volume of the loudspeaker in the audio and the ringer mode.

Abstract: A circuit, where distortions, caused by PSRR in a mobile phone, are significantly reduced, is achieved. The power supplyvoltage for a signal processing module in a mobile phone is specially filtered by Low Drop Out (LDO) linear voltage regulators or other means of filtering. By filtering the noise in the power supply of a signal processing module the following output stage will not amplify the ripples caused by said noise. In a bridge configuration there is no more the requirement of a perfect symmetrical design and layout of the signal processing module, therefore the costs for manufacturing, design and layout are significantly reduced.

Abstract: A circuit, which is enabling the superpositioning of different audio signals such as voice, music or ringer signals in a audio output device is achieved. The individual superpositioning can be activated and performed by a combination of resistors and switches without the need of an additional mixing amplifier as in prior art. One common output stage is used for all the signals activated and superpositioned. The adjustment of the amplitude of the output signal, which can be used for the volume adjustment of a loudspeaker, is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier through a current-voltage conversion. Said current-voltage conversion is performed by a string of resistors activated by a string of correspondent switches. This circuit reduces the power consumption, the chip area required and the offset and improves the power supply rejection rate (PSSR).

Abstract: A circuit where the same amplifiers and the same volume adjustment circuitry are used for the ringer mode as well as for the audio mode of a mobile phone is achieved. The volume adjustment in the audio and ringer mode is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier used in a bridge circuit through a current-voltage conversion. This volume adjustment circuit avoids the high power dissipation of a volume control through pulse width modulation (PWM) and avoids the risk of over-and undershooting of the amplifier's output signal due to a high slew rate in combination with the inductance of the loudspeaker. The current-voltage conversion is performed by a series of resistors activated by a series of correspondent switches. High impedance current less sense paths are eliminating the parasitic effect of the resistance of low cost standard switches to adjust the volume of the loudspeaker in the audio and the ringer mode.