초록 ▼

Response of a variable frequency switching constant on-time or adaptive on-time controlled power converter to a large step-up or step-down change in load is improved with a simple circuit that detects magnitude and polarity of a change in output voltage and initiates, extends or terminates conductio

Response of a variable frequency switching constant on-time or adaptive on-time controlled power converter to a large step-up or step-down change in load is improved with a simple circuit that detects magnitude and polarity of a change in output voltage and initiates, extends or terminates conduction of power pulses from an input source through said power converter. Both the amplitude and duration of undershoot or overshoot of the transient response are reduced or, alternatively, the capacitance of an output filter may be significantly reduced and still provide comparable transient performance. The fast adaptive on-time control is applicable to multi-phase power converters using phase managers or one or more phase-locked loops for interleaving of power pulses.

대표청구항 ▼

1. A power converter including a power stage including a switching arrangement and an inductor,a circuit for providing variable frequency constant on-time or variable frequency adaptive on-time control of said switching arrangement,a detector for detecting a step-up or step-down load transient, anda

1. A power converter including a power stage including a switching arrangement and an inductor,a circuit for providing variable frequency constant on-time or variable frequency adaptive on-time control of said switching arrangement,a detector for detecting a step-up or step-down load transient, anda control generator responsive to said detector for interrupting operation of said circuit providing variable frequency constant on-time or variable frequency adaptive on-time control of said switching arrangement for a duration of said step-up or step-down transient, wherein said detector includesa filter, anda comparator circuit applying a threshold to a detected step-up or step-down load transient whereby said duration of said step-up or step-down transient is determined. 2. The power converter as recited in claim 1, wherein said power stage has a buck converter topology. 3. The power converter as recited in claim 1, wherein said circuit for controlling on-time of said switching circuit provides constant on-time control. 4. The power converter a recited in claim 1, wherein said control generator extends duration of said on-time of said switching arrangement upon detection of a step-up load transient. 5. The power converter a recited in claim 1, wherein said control generator terminates on-time of said switching arrangement upon detection of a step-down load transient. 6. The power converter as recited in claim 1, wherein said circuit for controlling on-time of said switching circuit provides adaptive on-time control. 7. The power converter as recited in claim 1, wherein said detector discriminates between step-up and step-down load transients. 8. The power converter a recited in claim 7, wherein said detector circuit includes an emitter follower circuit. 9. The power converter as recited in claim 1, wherein said detector further includes a ripple eliminator circuit. 10. The power converter a as recited in claim 9, wherein said filter is a band-pass filter circuit and wherein said detector circuit includes a first comparator receiving an output of said band-pass filter for comparison with a voltage less than a reference voltage, anda second comparator receiving an output of said band-pass filter for comparison with a voltage greater than a reference voltage. 11. The power converter as recited in claim 10, wherein said first comparator and said second comparator are transconductance amplifiers. 12. The power converter as recited in claim 1 wherein an output of said control generator is applied directly to said circuit for providing variable frequency constant on-time or variable frequency adaptive on-time control of said switching arrangement. 13. The power converter as recited in claim 1 wherein an output of said control generator is applied to a gate receiving an output of said circuit for providing variable frequency constant on-time or variable frequency adaptive on-time control of said switching arrangement. 14. The power converter as recited in claim 1 wherein an output of said control generator is combined with an input voltage to said power converter to produce a result and the result applied directly to said circuit for providing variable frequency constant on-time or variable frequency adaptive on-time control of said switching arrangement. 15. The power converter as recited in claim 1 wherein said power converter is a multi-phase power converter. 16. The power converter as recited in claim 15 wherein interleaving power pulses is performed using a phase manager. 17. The power converter as recited in claim 15 wherein interleaving of power pulses is performed using a phase-locked loop. 18. The power converter a recited in claim 9, wherein said ripple eliminator circuit includes an emitter follower circuit. 19. The power converter as recited in claim 10, wherein said band-pass filter circuit is a high frequency band-pass filter circuit which passes frequencies sufficiently high to pass the highest anticipated slew rate of a detected load transient with relatively low attenuation.