Error voltage ripple compensation to extend bandwidth of a feedback loop in a DC-to-DC converter
AssigneeDell Products L.P.
InventorsBrent McDonald, Daniel Jenkins
Life of this patent
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Abstract
Control loop ripple voltage in an error amplifier may be the result of a non-linear time varying behavior of a switch mode power conversion process. An inverse waveform replica of the error amplifier control loop ripple voltage waveform may be generated to substantially cancel the non-linear loop dynamics introduced by the control loop ripple voltage. Once the control loop ripple voltage is substantially cancelled the bandwidth of the DC-to-DC converter control loop may be increased for faster loop response thus reducing the need for additional output filter capacitance.
Claims26
A DC-to-DC converter having error voltage ripple compensation for extending bandwidth in the feedback loop thereof, comprising:
- a DC-to-DC converter controlled by a pulse width modulation (PWM) generator, wherein the PWM generator charges and discharges an inductor;
- a feedback loop filter/amplifier having an input coupled to an output of the DC-to-DC converter;
- a ripple compensation voltage capacitor;
- a first current source coupled to the ripple compensation voltage capacitor, wherein the first current source charges the ripple compensation voltage capacitor when the PWM generator charges the inductor;
- a second current source coupled to the ripple compensation voltage capacitor, wherein the second current source discharges the ripple compensation voltage capacitor when the PWM generator discharges the inductor;
- a high pass filter and compensation scaler having an input coupled to the ripple compensation voltage capacitor;
- and
- a voltage adder having a first input coupled to an output of the feedback loop filter/amplifier, a second input coupled to an output of the high pass filter and compensation scaler, and an output coupled to an input of the PWM generator;
- wherein a ripple compensation voltage from the output of the high pass filter and compensation scaler and a feedback loop error voltage from the output of the feedback loop filter/amplifier are added together in the voltage adder such that ripple voltage on the feedback loop error voltage is substantially reduced to the input of the PWM generator.
A method to compensate for error voltage ripple in the feedback loop of a DC-to-DC converter, said method comprising the steps of:
- controlling a DC-to-DC converter with a pulse width modulation (PWM) generator, wherein the PWM generator charges and discharges an inductor;
- coupling a feedback loop filter/amplifier to an output of the DC-to-DC converter, wherein the feedback loop filter/amplifier generates a feedback loop error voltage to the PWM generator;
- charging a ripple compensation voltage capacitor with a first current source when the PWM generator charges the inductor;
- discharging the ripple compensation voltage capacitor with a second current source when the PWM generator discharges the inductor;
- generating a ripple compensation voltage from the charge on the ripple compensation voltage capacitor;
- and
- adding the ripple compensation voltage to the feedback loop error voltage so as to substantially reduce a ripple voltage on the feedback loop error voltage.
An information handling system powered from a DC-to-DC converter having error voltage ripple compensation for extending bandwidth in the feedback loop thereof, said system comprising:
- at least one processor powered from a DC-to-DC converter, the DC-to-DC converter being controlled by a pulse width modulation (PWM) generator, wherein the PWM generator charges and discharges an inductor;
- a feedback loop filter/amplifier having an input coupled to an output of the DC-to-DC converter;
- a ripple compensation voltage capacitor;
- a first current source coupled to the ripple compensation voltage capacitor, wherein the first current source charges the ripple compensation voltage capacitor when the PWM generator charges the inductor;
- a second current source coupled to the ripple compensation voltage capacitor, wherein the second current source discharges the ripple compensation voltage capacitor when the PWM generator discharges the inductor;
- a high pass filter and compensation scaler having an input coupled to the ripple compensation voltage capacitor;
- and
- a voltage adder having a first input coupled to an output of the feedback loop filter/amplifier, a second input coupled to an output of the high pass filter and compensation scaler, and an output coupled to an input of the PWM generator;
- wherein a ripple compensation voltage from the output of the high pass filter and compensation scaler and a feedback loop error voltage from the output of the feedback loop filter/amplifier are added together in the voltage adder such that ripple voltage on the feedback loop error voltage is substantially reduced to the input of the PWM generator.
Dependencies are inferred from the claim text.