Electrical switching systems including constant-power controllers and associated methods

1. An electrical switching system, comprising:

a switching device electrically coupled between a first node and a second node; and

a constant-power controller that generates a pulse width modulated signal to control the switching device and

(a) set a duration (ta) of the pulse width modulated signal during an active phase, at least partially based on a voltage (V s ) across the switching device, and

(b) set an amplitude of the pulse width modulated signal to regulate peak amplitude of current (I s ) flowing through the switching device;

wherein the constant-power controller being configured to control peak value of the pulse width modulated signal based on a difference between (a) a signal representing magnitude of current (I s ) flowing through the switching device and (b) a reference signal.

2. The electrical switching system of claim 1 , the constant-power controller further setting duration (t a ) of the pulse width modulated signal in the active phase at least partially by controlling duty cycle (t a /T) of the pulse width modulation signal.

3. The electrical switching system of claim 1 , the constant-power controller further setting duration (t a ) of the pulse width modulated signal in the active phase at least partially by controlling frequency (1/T) of the pulse width modulated signal.

4. The electrical switching system of claim 1 , wherein the constant-power controller amplifies difference between the signal representing magnitude of current (I s ) flowing through the switching device and the reference signal, to determine the peak value.

5. The electrical switching system of claim 4 , the constant-power controller further setting the pulse width modulated signal to have zero value when the pulse width modulated signal is in an inactive phase.

6. The electrical switching system of claim 1 , wherein the switching device comprises a field effect transistor (FET).

7. The electrical switching system of claim 6 , wherein the constant-power controller comprises:

a voltage sense module that generates a first signal representing voltage (V s ) across the switching device;

a comparison module that generates a third signal representing difference between (a) a second signal representing magnitude of current (I s ) flowing through the switching device and (b) a reference signal;

first and second driver switches generating the pulse width modulated signal from the third signal; and

a modulation module setting the first and second driver switches at least partially based on the first signal.

8. A constant-power control method of a switching device, comprising:

generating a first signal representing voltage (V s ) across the switching device;

generating a second signal representing magnitude of current (I s ) flowing through the switching device;

generating a third signal representing difference between the second signal and a reference signal; and

generating a pulse width modulated signal to control the switching device such that:

duration (t a ) of the pulse width modulation signal in an active phase is at least partially based on the first signal, and

peak value of the pulse width modulation signal is at least partially based on the third signal.

9. The method of claim 8 , further comprising controlling the duration (t a ) of the active phase at least partially by controlling duty cycle (t a /T) of the pulse width modulation signal.

10. The method of claim 8 , further comprising controlling the duration (t a ) of the active phase at least partially by controlling a frequency (1/T) of the pulse width modulation signal.

11. The method of any one of claim 10 , further comprising amplifying the third signal.

12. The method of claim 11 , wherein the pulse width modulation signal equals the third signal when the pulse width modulation signal is in its active phase.

13. The method of claim 12 , wherein the pulse width modulation signal has zero value when the pulse width modulation signal is in its inactive phase.

14. A constant-power controller, comprising:

a voltage sense module that generates a first signal representing voltage (V s ) across a switching device;

a comparison module that generates a third signal representing difference between (a) a second signal representing magnitude of current (I s ) flowing through the switching device and (b) a reference signal;

first and second driver switches that generate a pulse width modulation signal based on the third signal, to control the switching device; and

a modulation module configured to control the first and second driver switches such that duration (t a ) of an active phase of the pulse width modulation signal is at least partially based on the first signal.

15. The constant-power controller of claim 14 , the modulation module controlling the duration (t a ) of the pulse width modulation signal in the active phase at least partially by controlling duty cycle (t a /T) of the pulse width modulation signal.

16. The constant-power controller of claim 14 , the modulation module controlling the duration (t a ) of the pulse width modulation signal in the active phase at least partially by controlling frequency (1/T) of the pulse width modulation signal.

17. The constant-power controller of claim 16 , further comprising an amplifier that amplifies the third signal before receipt of the third signal by the first driver switch.

18. The constant-power controller of claim 17 , wherein the first and second driver switches generate the pulse width modulation signal such that the pulse width modulation signal has zero value when the pulse width modulation signal is in its inactive phase.

19. The constant-power controller of claim 14 , wherein the switching device comprises a field effect transistor (FET).