Switching power supply controller with high frequency current balance
View Patent ↗A controller for a multi-phase switching power supply shuffles the sequence of the phases in response to a load transient to prevent synchronization of one or more phases with high-frequency load transients. The sequence may be shuffled by varying the frequency and/or sequence of the switching control signals to introduce a random variation in the phases.
1. A method of forming a power supply controller comprising:
configuring the power supply controller to form switching control signals for a multi-phase switching power supply;
configuring an oscillator to form a clock signal having a frequency that is used to control the switching control signals; and
shuffling the sequence of the switching control signals by increasing the frequency to an increased frequency in response to a load transient and maintaining the increased frequency during the load transient.
2. The method of claim 1 where shuffling the sequence comprises varying the sequence of the switching control signals.
3. The method of claim 1 where shuffling the sequence comprises introducing a random variation to the switching control signals.
4. The method of claim 1 where shuffling the sequence comprises varying the frequency of the oscillator.
5. The method of claim 1 where the load transient is detected based on an error signal which is generated by an error amplifier in response to an output of the switching power supply and a reference signal.
6. A switching power supply controller comprising:
a modulation circuit to generate switching control signals for a multi-phase switching power supply;
an oscillator having a frequency that is used to control a frequency of the switching control signals wherein the oscillator forms a clock signal having the frequency; and
circuitry to shuffle the sequence of the switching control signals by varying a sequence of the switching control signals relative to each other without changing the frequency in response to a load transient.
7. The controller of claim 6 where the circuitry to shuffle the sequence comprises circuitry coupled to the driver logic to vary the sequence of the switching control signals.
8. The controller of claim 7 further including randomizer circuitry to randomly blank the clock signal during a load release.
9. The controller of claim 6 where:
the controller further comprises an error amplifier to generate an error signal in response to an output of the switching power supply and a reference signal;
the oscillator including an input to set the frequency in response to a resistance coupled to the terminal; and
the multi-phase switching power supply further comprises a diode and a resistor coupled in series between an output of the error amplifier and the input of the oscillator.
10. The controller of claim 9 further comprising a second diode coupled in series with the diode and resistor.
11. The controller of claim 6 where the circuitry to shuffle the sequence of the switching control signals shuffles the sequence when an output of the switching power supply goes out of regulation.
12. The controller of claim 6 where the circuitry to shuffle the sequence of the switching control signals shuffles the sequence during a blanking period of the switching control signals.
13. The controller of claim 9 where the diode and resistor are arranged to vary the frequency of the oscillator during a load release.
14. The controller of claim 9 where the circuitry to shuffle the sequence comprises an analog comparator coupled to the error amplifier to receive the error signal.
15. The controller of claim 6 where the circuitry to shuffle the sequence comprises a digital algorithm to monitor the status of a load.