Oscillator and associated direct current-to-direct current converter applying the oscillator
AssigneeElite Semiconductor Memory Technology Inc.
InventorYao-Wei Yang
Life of this patent
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Abstract
An oscillator includes a reference current generating circuit, a modulator circuit, and an oscillating circuit. The reference current generating circuit generates a first reference current. The modulator circuit generates a modulation current according to the first reference current and a feedback voltage, wherein the modulation current is negatively correlated with the feedback voltage. The oscillating circuit receives at least the modulation current, and generates an oscillating signal with an oscillating frequency according to at least the modulation current, wherein the oscillating frequency is varied according to the modulation current. The oscillator may be employed by a direct current (DC)-to-DC voltage converter.
Claims16
An oscillator, comprising:
- a reference current generating circuit, arranged to generate a first reference current;
- a modulator circuit, coupled to the reference current generating circuit, wherein the modulator circuit is arranged to generate a modulation current according to the first reference current and a feedback voltage, and the modulation current is negatively correlated with the feedback voltage, the modulator circuit comprising:
- a first transistor, having a source terminal coupled to the first reference current, and a gate terminal coupled to the feedback voltage, wherein the first transistor is controlled by the feedback voltage;
- and
- a current mirror, coupled to a drain terminal of the first transistor to generate the modulation current;
- and
- an oscillating circuit, coupled to the modulator circuit, wherein the oscillating circuit is arranged to receive at least the modulation current and generate an oscillating signal with an oscillating frequency according to at least the modulation current, wherein the oscillating frequency is varied according to the modulation current.
A direct current (DC)-to-DC voltage converter, comprising:
- an inductor-capacitor circuit, comprising at least an inductor and a capacitor, wherein the inductor-capacitor circuit is arranged to receive an inductor current from an input voltage source of the DC-to-DC converter via at least a switch to provide energy for a following loading;
- a feedback circuit, coupled to the inductor-capacitor circuit, wherein the feedback circuit is arranged to generate a feedback voltage according to the inductor current;
- and
- an oscillator, coupled to the feedback circuit, wherein the oscillator is arranged to generate an oscillating signal according to the feedback voltage, and the switch is controlled according to the oscillating signal, and the oscillator comprises:
- a reference current generating circuit, arranged to generate a first reference current;
- a modulator circuit, coupled to the reference current generating circuit, wherein the modulator circuit is arranged to generate a modulation current according to the first reference current and the feedback voltage generated from the feedback circuit, and the modulation current is negatively correlated with the feedback voltage, the modulator circuit comprising:
- a first transistor, having a source terminal coupled to the first reference current, and a gate terminal coupled to the feedback voltage, wherein the first transistor is controlled by the feedback voltage;
- and
- a current mirror, coupled to a drain terminal of the first transistor to generate the modulation current;
- and
- an oscillating circuit, coupled to the modulator circuit, wherein the oscillating circuit is arranged to receive at least the modulation current and generate the oscillating signal with an oscillating frequency according to at least the modulation current, wherein the oscillating frequency is varied according to the modulation current.
Dependencies are inferred from the claim text.