BIDIRECTIONAL SIGNAL CONVERSION
An embodiment includes coupling a first intermediate node between a first inductor and a first winding of a transformer to a reference node during a first portion of a first switching cycle, uncoupling the first intermediate node from the reference node and coupling the first intermediate node to a signal-storage element during a second portion of the first switching cycle, coupling a second winding of the transformer between the reference node and a second converter node during the second portion of the first switching cycle, and regulating a signal at the second converter node by controlling a duration of one of the first and second portions of the first switching cycle. For example, in an embodiment, bidirectional signal converter may perform the above steps to handle power transfer between two loads. Such a voltage converter may have improved conversion efficiency and a smaller size and lower component count as compared to a conventional bidirectional voltage converter. Furthermore, such a voltage converter may be operable with a common switching scheme regardless of the direction of power transfer, and without the need for an indicator of the instantaneous direction of power flow.
1 . A method, comprising:
coupling a first intermediate node between a first inductor and a first winding of a transformer to a reference node during a first portion of a first switching cycle;
uncoupling the first intermediate node from the reference node and coupling the first intermediate node to a signal-storage element during a second portion of the first switching cycle;
coupling a second winding of the transformer between the reference node and a second converter node during the second portion of the first switching cycle; and
regulating a signal at the second converter node by controlling a duration of one of the first and second portions of the first switching cycle.
2 . The method of claim 1 wherein the reference node comprises ground.
3 . The method of claim 1 wherein the signal-storage element comprises a capacitor.
4 . The method of claim 1 wherein coupling the first intermediate node to the signal-storage element comprises clamping a voltage across the first winding of the transformer to a voltage across the signal-storage element during the second portion of the first switching cycle.
5 . The method of claim 1 wherein coupling the second winding of the transformer during the second portion of the first switching cycle comprises coupling the second winding of the transformer across a capacitor that is coupled between the reference node and the second converter node.
6 . The method of claim 1 wherein coupling the second winding of the transformer during the second portion of the first switching cycle comprises clamping a voltage across the second winding of the transformer.
7 . The method of claim 1 wherein regulating the signal comprises regulating the voltage at the second converter node.
8 . The method of claim 1 , further comprising allowing a current through the second winding of the transformer to decay to substantially zero before coupling the second winding between the reference node and a second converter node during the second portion of the first switching cycle.
9 . The method of claim 1 , further comprising allowing a current through the first winding of the transformer to decay to substantially zero before uncoupling the first intermediate node from the reference node.
10 . The method of claim 1 , further comprising allowing a voltage across a switching circuit coupled between the first intermediate node and the signal storage element to decay to substantially zero before activating the switching circuit to couple the first intermediate node to the signal-storage element.
11 . The method of claim 1 , further comprising allowing a voltage across a switching circuit coupled between the first intermediate node and the signal storage element to decay to substantially a PN-junction forward-bias voltage level before activating the switching circuit to couple the first intermediate node to the signal-storage element.
12 . The method of claim 1 , further comprising:
coupling a second intermediate node between a second inductor and the first winding of the transformer to the reference node during a first portion of a second switching cycle;
uncoupling the second intermediate node from the reference node and coupling the second intermediate node to the signal-storage element during a second portion of the second switching cycle;
coupling the second winding of the transformer between the reference node and the second converter node during the second portion of the second switching cycle; and
regulating the signal at the second converter node by controlling a duration of one of the first and second portions of the second switching cycle.
13 . The method of claim 12 wherein the first portions of the first and second cycles overlap.
14 . The method of claim 12 wherein the second portions of the first and second cycles overlap.
15 . The method of claim 12 wherein:
coupling the second winding of the transformer between the reference node and the second converter node during the second portion of the first switching cycle comprises coupling the second winding of the transformer between the reference node and the second converter node according to a first polarity; and
coupling the second winding of the transformer between the reference node and the second converter node during the second portion of the second switching cycle comprises coupling the second winding of the transformer between the reference node and the second converter node according to a second polarity.