Method and apparatus for phase alignment in semi-resonant power converters
AssigneeInfineon Technologies Austria AG
InventorAmir Babazadeh
Life of this patent
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Abstract
Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and adjusts the duty cycles of the control signals for the phases so that the SR switches are switched off when zero or almost zero current is flowing through them.
Claims20
A multi-phase voltage converter, comprising:
- a plurality of phases, each phase comprising a synchronous rectification (SR) switch through which a half-cycle sinusoidal-like current is conducted when turned on;
- and
- a control circuit operable to:
- control cycle-by-cycle switching of each phase via respective pulse width modulation (PWM) control signals, each PWM control signal having a switching period and duty cycle;
- select one of the phases as a reference phase, wherein the switching period and duty cycle of the PWM control signal for the reference phase are set such that the half-cycle sinusoidal-like current conducted by the SR switch of the reference phase crosses zero or nearly crosses zero when the SR switch is turned off each switching cycle;
- set the switching period and duty cycle of the PWM control signals for the other phases to that of the reference phase;
- and
- adjust the duty cycle of the PWM control signals for the other phases such that the half-cycle sinusoidal-like current conducted by the SR switches of the other phases eventually cross zero or nearly cross zero when the SR switches are turned off each switching cycle.
A method of phase alignment for a multi-phase voltage converter, each phase of the multi-phase voltage converter including a synchronous rectification (SR) switch through which a half-cycle sinusoidal-like current is conducted when turned on, the method comprising:
- controlling cycle-by-cycle switching of each phase via respective pulse width modulation (PWM) control signals, each PWM control signal having a switching period and duty cycle;
- selecting one of the phases as a reference phase, wherein the switching period and duty cycle of the PWM control signal for the reference phase are set such that the half-cycle sinusoidal-like current conducted by the SR switch of the reference phase crosses zero or nearly crosses zero when the SR switch is turned off each switching cycle;
- setting the switching period and duty cycle of the PWM control signals for the other phases to that of the reference phase;
- and
- adjusting the duty cycle of the PWM control signals for the other phases such that the half-cycle sinusoidal-like current conducted by the SR switches of the other phases eventually cross zero or nearly cross zero when the SR switches are turned off each switching cycle.
Dependencies are inferred from the claim text.