A power supply with an output node (Npa), configured to supply a modulated voltage (Vpa) for a power amplifier, comprising: an alternating current component generator, configured to generate, at a respective output terminal, an alternating current component of the modulated voltage (Vpa) according to an envelope tracking signal; a direct current component generator, configured to generate, at a respective output terminal, a direct current component of the modulated voltage (Vpa) according to an operational voltage range for the power amplifier; and a transition accelerator, coupled to the respective output terminal of the direct current component generator to receive the direct current component and speed up transition of the modulated voltage (Vpa), wherein the transition accelerator comprises at least one of: a pull-up circuit, operable to accelerate a rise in the direct current component, wherein the transition accelerator is operable to turn on the pull-up circuit during low-to-high transition intervals of the direct current component, and a pull-down circuit, operable to accelerate a drop in the direct current component, wherein the transition accelerator is operable to turn on the pull-down circuit during high-to-low transition intervals of the direct current component; wherein the respective output terminal of the direct current component generator is coupled to the respective output terminal of the alternating current component generator and to the output node (Npa) to combine together the direct current component and the alternating current component, and thereby to output the modulated voltage (Vpa). an alternating current component generator, configured to generate, at a respective output terminal, an alternating current component of the modulated voltage (Vpa) according to an envelope tracking signal; a direct current component generator, configured to generate, at a respective output terminal, a direct current component of the modulated voltage (Vpa) according to an operational voltage range for the power amplifier; and a transition accelerator, coupled to the respective output terminal of the direct current component generator to receive the direct current component and speed up transition of the modulated voltage (Vpa), wherein the transition accelerator comprises at least one of: a pull-up circuit, operable to accelerate a rise in the direct current component, wherein the transition accelerator is operable to turn on the pull-up circuit during low-to-high transition intervals of the direct current component, and a pull-down circuit, operable to accelerate a drop in the direct current component, wherein the transition accelerator is operable to turn on the pull-down circuit during high-to-low transition intervals of the direct current component; a pull-up circuit, operable to accelerate a rise in the direct current component, wherein the transition accelerator is operable to turn on the pull-up circuit during low-to-high transition intervals of the direct current component, and a pull-down circuit, operable to accelerate a drop in the direct current component, wherein the transition accelerator is operable to turn on the pull-down circuit during high-to-low transition intervals of the direct current component;