Controller including a common current-sense device for power switches of a power converter
A controller for a power converter includes a current-sense device couplable in series with switched terminals of power switches of interleaved switching regulators and configured to produce a current-sense signal. The controller also includes an error amplifier configured to produce an error signal as a function of a characteristic of the power converter. The controller also includes a duty-cycle controller configured to sample the current-sense signal at mid-points of duty cycles of the power switches and regulate the characteristic as a function of the error signal and the current-sense signal.
1. A controller for use with a power converter formed with interleaved switching regulators, comprising:
a common current-sense device couplable in series with switched terminals of power switches of said interleaved switching regulators and configured to produce a current-sense signal representative of currents in said power switches;
an error amplifier configured to produce an error signal as a function of a characteristic of said power converter; and
a duty-cycle controller configured to sample said current-sense signal at mid-points of duty cycles of said power switches and regulate said characteristic as a function of said error signal and said current-sense signal sampled at said mid-points.
2. The controller as recited in claim 1 , wherein said current-sense device is a common current-sense resistor.
3. The controller as recited in claim 1 , wherein said characteristic of said power converter is an output voltage.
4. The controller as recited in claim 1 , wherein said error amplifier is configured to produce said error signal as a function of a reference voltage.
5. The controller as recited in claim 1 , further comprising a comparator configured to produce an average current signal as a function of said current-sense signal sampled at said mid-points and said error signal.
6. The controller as recited in claim 5 , wherein said duty-cycle controller is configured to produce drive signals for and to control said duty cycles of said power switches as a function of said average current signal.
7. The controller as recited in claim 1 , wherein a sampled current-sense signal represents a current through a switched terminal of one of said power switches when a current flowing through a switched terminal of another of said power switches is substantially zero.
8. A method for use with a power converter formed with interleaved switching regulators, comprising:
producing a current-sense signal with a common current-sense device in series with switched terminals of power switches of said interleaved switching regulators, said current-sense signal being representative of currents in said power switches;
producing an error signal as a function of a characteristic of said power converter;
sampling said current-sense signal at mid-points of duty cycles of said power switches; and
regulating said characteristic as a function of said error signal and said current-sense signal sampled at said mid-points.
9. The method as recited in claim 8 , wherein producing said error signal is a function of a reference voltage.
10. The method as recited in claim 8 , further comprising producing an average current signal as a function of said current-sense signal sampled at said mid-points and said error signal.
11. The method as recited in claim 10 , further comprising producing drive signals for and to control said duty cycles of said power switches as a function of said average current signal.
12. The method as recited in claim 8 , wherein a sampled current-sense signal represents a current through a switched terminal of one of said power switches when a current flowing through a switched terminal of another of said power switches is substantially zero.
13. A power converter, comprising:
a first interleaved switching regulator including a first power switch;
a second interleaved switching regulator including a second power switch; and
a controller, comprising:
a common current-sense device couplable in series with switched terminals of said first and second power switches and configured to produce a current-sense signal representative of currents in said first and second power switches;
an error amplifier configured to produce an error signal as a function of a characteristic of said power converter; and
a duty-cycle controller configured to sample said current-sense signal at mid-points of duty cycles of said first and second power switches and regulate said characteristic as a function of said error signal and said current-sense signal sampled at said mid-points.
14. The power converter as recited in claim 13 , wherein said current-sense device is a common current-sense resistor.
15. The power converter as recited in claim 13 , wherein said characteristic of said power converter is an output voltage.
16. The power converter as recited in claim 13 , wherein said error amplifier is configured to produce said error signal as a function of a reference voltage.
17. The power converter as recited in claim 13 , wherein said controller further comprises a comparator configured to produce an average current signal as a function of said current-sense signal sampled at said mid-points and said error signal.
18. The power converter as recited in claim 17 , wherein said duty-cycle controller is configured to produce drive signals for and to control said duty cycles of said first and second power switches as a function of said average current signal.
19. The power converter as recited in claim 13 , wherein a sampled current-sense signal represents a current through a switched terminal of said first power switch when a current flowing through a switched terminal of said second power switch is substantially zero.
20. The power converter as recited in claim 13 , wherein said first interleaved switching regulator is controlled with a duty cycle 180 degrees out of phase with respect to said second interleaved switching regulator.