Zero-current crossing detection circuits
First Claim
1. A circuit, comprising:
- a buck converter comprising a high-side switch, a low-side switch, and an inductor;
a zero-current crossing detection circuit comprising a reference switch coupled to a current source, wherein the reference switch is controllable conjointly with the low-side switch;
an amplifier coupled to;
(a) a first node between the current source and the reference switch, wherein the first node has a positive voltage value during an interval of interest, and (b) a second node between the low-side switch and the inductor, wherein the second node has a negative voltage value during the interval of interest; and
a comparator coupled to the amplifier, the comparator configured to output a flag signal in response to a detection that a decreasing current through the inductor has reached a predetermined value.
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Accused Products
Abstract
Systems and methods for zero-current crossing detection circuits. In some embodiments, a circuit may include a buck converter comprising a high-side switch, a low-side switch, and an inductor; a zero-current crossing detection circuit comprising a reference switch coupled to a current source, where the reference switch is controllable conjointly with the low-side switch; an amplifier coupled to: (a) a first node between the current source and reference switch, where in operation the first node has a positive voltage value during an interval of interest, and a (b) second node between the low-side switch and the inductor, where in operation the second node has a negative voltage value during the interval of interest; and a comparator coupled to the amplifier, the comparator configured to output a flag in response to a detection that a decreasing current through the inductor has reached a predetermined value.
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Citations
18 Claims
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1. A circuit, comprising:
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a buck converter comprising a high-side switch, a low-side switch, and an inductor; a zero-current crossing detection circuit comprising a reference switch coupled to a current source, wherein the reference switch is controllable conjointly with the low-side switch; an amplifier coupled to;
(a) a first node between the current source and the reference switch, wherein the first node has a positive voltage value during an interval of interest, and (b) a second node between the low-side switch and the inductor, wherein the second node has a negative voltage value during the interval of interest; anda comparator coupled to the amplifier, the comparator configured to output a flag signal in response to a detection that a decreasing current through the inductor has reached a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A zero-current crossing detection circuit, comprising:
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a current source; a reference switch coupled to the current source at a first node, wherein a gate terminal of the reference switch is coupled to a gate terminal of a low-side switch of a DC-to-DC converter, the DC-to-DC converter comprising; (a) a high-side switch coupled to the low-side switch at a second node; and (b) an inductor coupled to the second node, wherein in operation the first node has a positive voltage and the second node has a negative or a positive voltage depending upon the operation cycle; a comparator configured to output a flag signal in response to a detection that a decreasing current through the inductor has reached a predetermined value greater than zero, wherein the predetermined value is selected to compensate for a delay between the detection and a subsequent turning off of the low-side switch to block the decreasing current before it reaches or drops below zero; and an amplifier having a pair of differential inputs coupled to the first and second nodes and a pair of differential outputs coupled to the comparator. - View Dependent Claims (11, 12, 13, 14)
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15. An electronic device, comprising:
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a DC-to-DC converter; and a zero-current crossing detection circuit coupled to the DC-to-DC converter, the zero-crossing detection circuit configured to output a flag signal in response to a decreasing current through an inductor within the DC-to-DC converter having reached a predetermined value, at least in part, by comparing;
(a) a positive voltage at a first node between a current source and a reference switch against (b) a negative voltage at a second node coupled to the inductor. - View Dependent Claims (16, 17, 18)
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Specification