Multimode operation DC-DC converter
Embodiments for at methods, apparatus and systems for operating a voltage regulator are disclosed. One apparatus includes a switching voltage regulator, wherein the switching voltage regulator includes a series switch element, a shunt switch element, a switching controller and a switched output filter. The switching controller is configured to generate a switching voltage through controlled closing and opening of the series switch element and the shunt switch element. The switched output filter filters the switching voltage and generates a regulated output voltage, wherein the switched output filter includes a plurality of capacitors that are selectively included within the switched output filter.
1. A switching voltage regulator, comprising:
a series switch element;
a shunt switch element;
a switching controller configured to generate a switching voltage through controlled closing and opening of the series switch element and the shunt switch element;
a switched output filter for filtering the switching voltage and generating a regulated output voltage, wherein the switched output filter comprises a plurality of capacitors that are selectively included within the switched output filter; and
a controllable current source connectable in series with a capacitor of the plurality of capacitors of the switched output filter; and wherein
the switching controller is operative to:
disconnect the capacitor of the plurality of capacitors of the switched output filter when the regulated output voltage is to be changed from the first value to the second value;
change the regulated output voltage from the first value to the second value;
controllably connect the controllable current source in series with the capacitor, wherein substantially all of a current provided by the controllable current source flows through the capacitor to charge the capacitor after the regulated output voltage has changed to the second value; and
reconnect the capacitor to the switched output filter.
2. The switching voltage regulator of claim 1 , further comprising determining whether the switching voltage regulator is switching from an envelope tracking mode to a non-envelope tracking mode.
3. The switching voltage regulator of claim 1 , wherein the switching voltage regulator receives an indicator that the switching voltage regulator is switching from an envelope tracking mode to a non-envelope tracking mode.
4. The switching voltage regulator of claim 1 , wherein the capacitor is charged until a voltage on the capacitor is approximately equal to the regulated output voltage while maintaining a voltage ripple on the regulated output voltage within a predetermined threshold.
5. The switching voltage regulator of claim 1 , further comprising ramping a magnitude of current conducted or sourced by the controllable current source upon determining the switching voltage regulator is switching, from an envelope tracking mode to a non-envelope tracking mode.
6. The switching voltage regulator of claim 1 , further comprising a controller operative to control selection of two or more switched output filter settings.
7. The switching voltage regulator of claim 1 , wherein selection of the settings of the switched output filter can be made as frequently as once per slot of a transmission protocol of a communications device utilizing the switching voltage regulator.
8. A method of operating a voltage regulator, comprising:
generating, by a switching controller, a switching voltage through controlled closing and opening of a series switch element and a shunt switch element;
generating, by a switchable output filter, a regulated output voltage by filtering the switching voltage, wherein the switchable output filter comprises a plurality of capacitors that are selectively included within the switchable output filter;
disconnecting a capacitor of the plurality of capacitors of the switchable output filter when the regulated output voltage is to be changed from the first value to the second value;
changing the regulated output voltage from the first value to the second value;
charging the capacitor after the regulated output voltage has changed to the second value by controllably connecting a controllable current source in series with the capacitor, wherein substantially all of a current provided by the controllable current source flows through the capacitor to charge the capacitor after the regulated output voltage has changed to the second value; and
reconnecting the capacitor to the switchable output filter.
9. The method of claim 8 , further comprising determining whether the switching voltage regulator is switching from an envelope tracking mode to a non-envelope tracking mode.
10. The method of claim 8 , wherein the switching voltage regulator receives an indicator that the switching voltage regulator is switching from an envelope tracking mode to a non-envelope tracking mode.
11. The method of claim 8 , wherein a magnitude of current conducted or sourced by the controllable current source comprises ramping the value of the controllable current source upon determining the switching voltage regulator is switching from an envelope tracking mode to a non-envelope tracking mode.
12. The method of claim 8 , further comprising selecting one of two or more switched output filter settings.
13. The method of claim 8 , wherein selecting the settings of the switchable output filter can be made as frequently as once per slot of a transmission protocol of a communications device utilizing the switching voltage regulator.
14. A mobile device, comprising:
a transmitter for transmitting communications signals;
a power amplifier for amplifying the communications signals before transmission;
a multiple mode switching voltage regulator for providing a regulated output voltage to the power amplifier, the multiple mode switching voltage regulator, comprising;
a series switch element;
a shunt switch element;
a switching controller configured to generate a switching voltage through controlled closing and opening of the series switch element and the shunt switch element;
a switched output filter for filtering the switching voltage and generating a regulated output voltage, wherein the switched output filter comprises a plurality of capacitors that are selectively included within the switched output filter; and
a controllable current source connectable in series with a capacitor of the plurality of capacitors of the switched output filter; and wherein
the switching controller is operative to:
disconnect the capacitor of the plurality of capacitors of the switched output filter when the regulated output voltage is to be changed from the first value to the second value;
change the regulated output voltage from the first value to the second value;
controllably connect the controllable current source in series with the capacitor, wherein substantially all of a current provided by the controllable current source flows through the capacitor to charge the capacitor after the regulated output voltage has changed to the second value; and
reconnect the capacitor to the switched output filter.