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US 9,093,986 B2Granted
Pulse width modulation synchronization of switched mode power converters
AssigneePowervation Limited
InventorsEamon O'Malley, Paul Kelleher, Karl Rinne, Basil Almukhtar
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Abstract
The present disclosure is directed generally to switch mode power supplies operating in a master-slave configuration and provides a method of synchronizing the PWM outputs from the master and slave devices to avoid problems such, for example, as the generation of beat frequencies.
Claims40
A method of synchronizing a PWM device to a synchronization (sync) signal, the PWM device generating a primary PWM output signal from a clock circuit, the method comprising:
- determining when a frequency of the primary PWM output of the PWM device is within a predetermined error margin of a frequency of the sync signal;
- upon making such a determination, adjusting a clock circuit of the PWM device to force the frequency of the primary PWM output of the PWM device to match the frequency of the sync signal, and
- upon reaching this condition, aligning a phase of the primary PWM output of the PWM device with respect to a phase of the sync signal such that there is a phase offset between the sync signal and the primary PWM output,
- wherein the step of determining when the frequency of the primary PWM output of the PWM device is within a predetermined frequency error margin of the sync signal comprises:
- counting a number of sync pulses received within a period defined by a predetermined count of primary PWM pulses of slave devices;
- and
- determining if the count of sync pulses is within a predetermined count margin of the predetermined count.
4 more elements
A PWM controller for generating at least one PWM control signal, comprising:
- a clock circuit for generating a clock signal, wherein the controller is configured to derive at least one PWM control signal from a clock input;
- and
- a sync module having a sync input for receiving a sync signal to which said at least one PWM control signal is to be synchronized, the sync module also comprising
- a frequency comparator for detecting a condition when a frequency of the sync signal is within a predetermined range of the at least one PWM control signal, wherein the frequency comparator comprises a first counter for counting pulses in the at least one PWM control signal and a second counter counting pulses arriving at the sync input, the sync module responsive to adjust the clock circuit to cause a frequency of at least one PWM control signal to match the frequency of the sync signal, the sync module being adapted upon matching the frequency of at least one PWM control signal to the frequency of the sync signal to align a phase of the PWM control signal relative to the sync signal,
- wherein the sync module is adapted to include a phase offset between the sync signal and a primary PWM output when aligning a phase of the primary PWM output with respect to a phase of the sync signal.
2 more elements
A PWM controller for generating at least one PWM control signal, comprising:
- a clock circuit for generating a clock signal, wherein the controller is configured to derive at least one PWM control signal from a clock input;
- and
- a sync module having a sync input for receiving a sync signal to which said at least one PWM control signal is to be synchronized, the sync module also comprising
- a frequency comparator for detecting a condition when a frequency of the sync signal is within a predetermined range of the at least one PWM control signal,
- wherein the frequency comparator comprises a first counter for counting pulses in the at least one PWM control signal and a second counter counting for pulses arriving at the sync input, the sync module responsive to adjust the clock circuit to cause a frequency of at least one PWM control signal to match the frequency of the sync signal, the sync module being adapted upon matching the frequency of at least one PWM control signal to the frequency of the sync signal to align a phase of the PWM control signal relative to the sync signal,
- wherein the-controller is programmable as either a master device or a slave device, and wherein as a master device the controller is further adapted to generate the sync signal from the primary PWM control signal for transmission as the sync input to at least one additional controller programmable as a slave device.
3 more elements
A method of synchronizing a PWM device to a synchronization (sync) signal, the PWM device generating a primary PWM output signal from a clock circuit, the method comprising:
- determining when a frequency of the primary PWM output signal of the PWM device is within a predetermined error margin of a frequency of the sync signal;
- upon making such a determination, adjusting a clock circuit of the PWM device to force the frequency of the primary PWM output of the PWM device to match the frequency of the sync signal, and
- upon reaching this condition, aligning a phase of the primary PWM output of the PWM device with respect to a phase of the sync signal such that there is a phase offset between the sync signal and the primary PWM output,
- wherein a rate of adjustment of the frequency from the clock circuit is limited to maintain stability of the clock circuit.
1 more element
A PWM controller for generating at least one PWM control signal, comprising:
- a clock circuit for generating a clock signal, wherein the controller is configured to derive at least one PWM control signal from a clock input;
- and
- a sync module having a sync input for receiving a sync signal to which said at least one PWM control signal is to be synchronized, the sync module also comprising
- a frequency comparator for detecting a condition when a frequency of the sync signal is within a predetermined range of the at least one PWM control signal, wherein the frequency comparator comprises a first counter for counting pulses in the at least one PWM control signal and a second counter counting pulses arriving at the sync input, the sync module responsive to adjust the clock circuit to cause a frequency of at least one PWM control signal to match the frequency of the sync signal, the sync module being adapted upon matching the frequency of at least one PWM control signal to the frequency of the sync signal to align a phase of the PWM control signal relative to the sync signal,
- wherein the sync module comprises a phase locked loop or a delay locked loop and an adjustable oscillator providing a reference clock signal to which the phase locked loop or delay locked loop locks, a frequency of the adjustable oscillator being responsive to an oscillator trim value.
2 more elements
A PWM controller for generating at least one PWM control signal, comprising:
- a clock circuit for generating a clock signal, wherein the controller is configured to derive at least one PWM control signal from a clock input;
- and
- a sync module having a sync input for receiving a sync signal to which said at least one PWM control signal is to be synchronized, the sync module also comprising
- a frequency comparator for detecting a condition when a frequency of the sync signal is within a predetermined range of the at least one PWM control signal, wherein the frequency comparator comprises a first counter for counting pulses in the at least one PWM control signal and a second counter counting pulses arriving at the sync input, the sync module responsive to adjust the clock circuit to cause a frequency of at least one PWM control signal to match the frequency of the sync signal, the sync module being adapted upon matching the frequency of at least one PWM control signal to the frequency of the sync signal to align a phase of the PWM control signal relative to the sync signal,
- wherein the sync module is adapted to align a phase of a primary PWM output during an inactive period in a switching cycle of the primary PWM output to ensure no PWM pulse is lost, cut short or extended during synchronization.
2 more elements
Dependencies are inferred from the claim text.