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US 8,896,284 B2Granted
DC-DC converter using internal ripple with the DCM function
AssigneeTexas Instruments Incorporated
InventorJiwei Fan
Life of this patent
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Abstract
A DC-DC converter, having an input voltage and an output voltage, includes an inductor and a switch switching the input voltage to an input side of the inductor, where a feedback path controlling initiation of closing the switch includes capacitive coupling of the voltage at the input side of the inductor.
Claims13
A DC-DC converter receiving an input voltage and generating an output voltage, comprising:
- an inductor;
- a switch switching the input voltage to a first side of the inductor;
- a comparator controlling initiation of closing the switch;
- and,
- the first side of the inductor capacitively coupled to a first input of the comparator;
- a second switch switching the first side of the inductor to ground;
- circuitry receiving a voltage at the first side of the inductor, receiving a state of the second switch, and controlling at least part of the signal path between the first side of the inductor and the first input of the comparator for providing a signal at a first strength to the first input of the comparator;
- and,
- the circuitry configured to provide the signal at a second strength less than the first strength from the first side of the inductor to the first input of the comparator only when the circuitry determines that a discontinuous conduction mode (DCM) exists for the inductor;
- further comprising:
- a resistance comprising a series combination of a first resistor having a resistance much greater than a second resistor in the path between the first side of the inductor and the first input of the comparator;
- a third switch in parallel with the first resistor;
- and,
- the circuitry configured to cause the third switch to open when the circuitry determines that a DCM exists for the inductor.
11 more elements
A DC-DC converter receiving an input voltage and generating an output voltage, comprising:
- an inductor;
- a switch switching the input voltage to a first side of the inductor;
- a comparator controlling initiation of closing the switch;
- and,
- the first side of the inductor capacitively coupled to a first input of the comparator;
- a differential difference amplifier having an output that is electrically coupled to the first input of the comparator;
- the differential difference amplifier having a first input electrically coupled to the output voltage;
- the differential difference amplifier having a second input connected to a first reference voltage that is variable;
- and
- reference adjust circuitry, having a first input electrically coupled to a fraction of the output voltage and a second input electrically coupled to a second reference voltage that is constant, the reference adjust circuitry integrating a difference between the fraction of the output voltage and the second reference voltage and adding the integrated difference to the second reference voltage to generate the first reference voltage.
7 more elements
A DC-DC converter receiving an input voltage and generating an output voltage, comprising:
- an inductor;
- a switch switching the input voltage to a first side of the inductor;
- a comparator controlling initiation of closing the switch;
- and,
- the first side of the inductor capacitively coupled to a first input of the comparator;
- a feedback path comparing a fraction of the output voltage to a first reference voltage;
- an amplifier receiving a fraction of the output voltage and a second reference voltage, and having an amplifier output that is the difference between the fraction of the output voltage and the second reference voltage;
- a threshold circuit determining whether the magnitude of the output of the amplifier is greater than a threshold;
- an integrator integrating the output of the amplifier only when the threshold circuit determines that the magnitude of the output of the amplifier is greater than the threshold;
- and,
- an adder, adding an output of the integrator to the first reference voltage to adjust the first reference voltage.
8 more elements
Dependencies are inferred from the claim text.