| 主权项 |
1. A method to achieve a differential audio amplifier, wherein a supply voltage of the amplifier is regulated by an envelope of audio signals, generating output signals free or with only very limited clipping comprising the steps of:
providing a supply voltage, an inverting buck-boost DC/DC converter, a Vmid level shifter, a control block, capable of controlling said buck-boost DC/DC converter, and a differential speaker amplifier of a portable device, wherein the differential speaker amplifier has dynamic positive and negative supply rails; connecting the positive supply rail directly to a negative port of the supply voltage; supplying the negative supply rail of the differential speaker amplifier by an output of the inverting buck-boost DC/DC converter, which is connected to a positive port of the supply voltage as input voltage, wherein the control block controls the operation of the inverting buck-boost DC/DC converter; and shifting the arithmetic average of input signals of the differential audio amplifier to an arithmetic average of the voltage levels of the positive and negative supply rails by the Vmid level shifter, wherein the input signals of the differential audio amplifier comprise a positive input signal and a negative input signal. |
