Power factor correction with carrier control and input voltage sensing
AssigneeChampion Microelectronic Corp.
InventorJeffrey H. Hwang
Life of this patent
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Abstract
A switching power supply which uses carrier control and input voltage sensing. In one aspect, an output voltage is monitored to form a carrier signal. The carrier signal is compared to a signal that is representative of the input current in order to control the switching duty cycle. In addition, a signal representative of the input voltage is summed with the signal that is representative of the input current, or with the carrier signal, in order to effectively control the switching duty cycle under light load conditions and conditions in which the input voltage can vary.
Claims43
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating an input current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- control circuitry coupled to the switch for controlling operation of the switch by comparing a carrier signal to a signal representative of the input current, wherein the carrier signal is representative of a level of the output voltage;
- and
- means for summing an input voltage sensing signal with the signal representative of the input current.
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating an input current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- control circuitry coupled to the switch for controlling operation of the switch by comparing a carrier signal to a signal representative of the input current, wherein the carrier signal is representative of a level of the output voltage;
- and
- means for summing an input voltage sensing signal with the carrier signal.
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating an input current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- control circuitry coupled to the switch for controlling a duty cycle of the switch so that the input current is maintained substantially in-phase with an AC input voltage provided by the source without having to multiply an input voltage sensing signal with a signal representative of the output voltage;
- and
- means for adjusting the duty cycle of the switch in response to changes in the effective level of the AC input voltage the means for adjusting coupled to the control circuitry.
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating an input current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- an error amplifier for forming an error signal that is representative of a difference between the output voltage and a desired level for the output voltage;
- a signal generator for forming a periodic carrier signal based on the error signal;
- an input current sensing amplifier for forming a signal that is representative of the input current;
- a summing element for summing the signal that is representative of the input current with a signal that is representative of the input voltage, thereby forming a combined signal;
- and
- a comparator for comparing the combined signal to the periodic carrier signal, wherein an output of the comparator controls operation of the switch.
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating an input current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- an error amplifier for forming an error signal that is representative of a difference between the output voltage and a desired level for the output voltage;
- a signal generator for forming a periodic carrier signal based on the error signal;
- an input current sensing amplifier for forming a signal that is representative of the input current;
- summing element for summing the periodic carrier signal with a signal that is representative of the input voltage, thereby forming a combined signal;
- and
- a comparator for comparing the combined signal to the signal that is representative of the input current, wherein an output of the comparator controls operation of the switch.
Dependencies are inferred from the claim text.