Feedback based buck timing of a direct current (DC)-DC converter

1. Switching power supply circuitry adapted to provide a first buck output signal and comprising:

at least a first shunt switching element coupled between a ground and an output inductance node; and

switching control circuitry adapted to select one of an ON state and an OFF state of the first shunt switching element such that the switching control circuitry is inhibited from selecting the ON state of the first shunt switching element when the buck output signal is above a first threshold.

2. The circuitry of claim 1 wherein the switching power supply circuitry further comprises series switching circuitry coupled between a direct current (DC) power supply and the output inductance node.

3. The circuitry of claim 2 wherein the DC power supply is adapted to provide a DC power supply signal to the series switching circuitry.

4. The circuitry of claim 2 wherein the DC power supply is a battery.

5. The circuitry of claim 2 further comprising the DC power supply.

6. The circuitry of claim 1 wherein the switching control circuitry is adapted to provide a first shunt control signal to the first shunt switching element.

7. The circuitry of claim 6 wherein the first shunt switching element operates in the one of the ON state and the OFF state based on the first shunt control signal.

8. The circuitry of claim 1 wherein the switching power supply circuitry further comprises a first inductive element coupled to the output inductance node and adapted to have an inductive element current.

9. The circuitry of claim 8 wherein the switching power supply circuitry further comprises at least a first series switching element coupled in series between a direct current (DC) power supply and the output inductance node, such that when an OFF state of the first series switching element is selected, the inductive element current drives the first buck output signal toward the ground.

10. The circuitry of claim 1 wherein the switching control circuitry is further adapted to receive the first buck output signal.

11. The circuitry of claim 10 wherein the switching power supply circuitry further comprises at least a first series switching element coupled in series between a direct current (DC) power supply and the output inductance node, such that the switching control circuitry is adapted to use the first buck output signal as verification that the first series switching element is in an OFF state.

12. The circuitry of claim 1 wherein the switching power supply circuitry further comprises a second shunt switching element coupled in series with the first shunt switching element between the output inductance node and the ground.

13. The circuitry of claim 12 wherein a series coupling of the first shunt switching element and the second shunt switching element provides a sub-buck output signal to the switching control circuitry.

14. The circuitry of claim 13 wherein the switching power supply circuitry further comprises at least a first series switching element coupled in series between a direct current (DC) power supply and the output inductance node, such that the switching control circuitry is adapted to use the sub-buck output signal as verification that the first series switching element is in an OFF state.

15. The circuitry of claim 1 wherein the first shunt switching element is an N-type metal-oxide-semiconductor (NMOS) transistor element.

16. The circuitry of claim 1 further comprising:

a first radio frequency (RF) power amplifier (PA) comprising:

a first non-quadrature PA path having a first single-ended output; and

a first quadrature PA path coupled between the first non-quadrature PA path and an antenna port, such that the first quadrature PA path has a first single-ended input, which is coupled to the first single-ended output; and

a second RF PA comprising a second quadrature PA path coupled to the antenna port,

wherein the antenna port is configured to be coupled to an antenna.

17. The circuitry of claim 1 further comprising:

a first multi-mode multi-band quadrature radio frequency (RF) power amplifier (PA) coupled to multi-mode multi-band alpha switching circuitry via a single alpha PA output; and

the multi-mode multi-band alpha switching circuitry having:

a first alpha non-linear mode output associated with a first non-linear mode RF communications band; and

a plurality of alpha linear mode outputs, such that each of the plurality of alpha linear mode outputs is associated with a corresponding one of a first plurality of linear mode RF communications bands.

18. The circuitry of claim 1 further comprising:

a first radio frequency (RF) power amplifier (PA) comprising a first final stage having a first final bias input, such that bias of the first final stage is via the first final bias input;

PA control circuitry;

a PA-digital communications interface (DCI) coupled between a digital communications bus and the PA control circuitry; and

a final stage current digital-to-analog converter (IDAC) coupled between the PA control circuitry and the first final bias input.

19. The circuitry of claim 1 further comprising:

a first radio frequency (RF) power amplifier (PA) having a first final stage and adapted to:

receive and amplify a first RF input signal to provide a first RF output signal; and

receive a first final bias signal to bias the first final stage;

PA bias circuitry adapted to receive a bias power supply signal and provide the first final bias signal based on the bias power supply signal; and

a direct current (DC)-DC converter adapted to receive a DC power supply signal from a DC power supply and provide the bias power supply signal based on the DC power supply signal, such that a voltage of the bias power supply signal is greater than a voltage of the DC power supply signal.

20. The circuitry of claim 1 further comprising:

a direct current (DC)-DC converter comprising:

the first switching power supply, which provides a power amplifier (PA) envelope power supply comprising a charge pump buck converter coupled to radio frequency (RF) PA circuitry; and

a PA bias power supply comprising a charge pump coupled to the RF PA circuitry; and

the RF PA circuitry.

21. The circuitry of claim 1 further comprising:

multi-mode multi-band radio frequency (RF) power amplification circuitry having at least a first RF input and a plurality of RF outputs, such that:

configuration of the multi-mode multi-band RF power amplification circuitry associates one of the at least the first RF input with one of the plurality of RF outputs; and

the configuration is associated with at least a first look-up table (LUT);

power amplifier (PA) control circuitry coupled between the multi-mode multi-band RF power amplification circuitry and a PA-digital communications interface (DCI), such that the PA control circuitry has at least the first LUT, which is associated with at least a first defined parameter set; and

the PA-DCI, which is coupled to a digital communications bus.

22. A method comprising:

providing at least a first shunt switching element of a first switching power supply, such that at least the first shunt switching element is coupled between a ground and an output inductance node;

providing switching control circuitry of the first switching power supply;

providing a buck output signal from the output inductance node;

selecting one of an ON state and an OFF state of the first shunt switching element;

when the buck output signal is above a first threshold, inhibiting selecting the ON state of the first shunt switching element; and

providing a first switching power supply output signal based on the buck output signal.