AC-DC converter for wide range output voltage and high switching frequency
View Patent ↗An electrical circuit includes an input for an AC input voltage coupled to a first inductive element with first and second outputs coupled to respective first and second nodes, and a four-quadrant (4-Q) switch coupled between the first and second nodes. A capacitor is coupled between the first node and a third node, a second inductive element is coupled between the third node and the second node, and a first bidirectional device and a first diode are coupled in series between a positive output node and a negative output node. A first output of the second inductive element is coupled between the first bidirectional device and the first diode. A second bidirectional device and a second diode are coupled in series between the positive output node and the negative output node. A second output of the second inductive element is coupled between the second bidirectional device and the second diode.
1. An AC-DC converter comprising:
a coupled inductor operable to receive an AC input voltage and having first and second outputs connected to respective first and second nodes;
a four-quadrant (4-Q) switch connected between the first and second nodes;
a capacitor connected between the first node and a third node;
an inductive element connected between the third node and the second node, the inductive element having a first output terminal and a second output terminal;
a second switch and a first diode connected in series between a first output node and a second output node, wherein the first output terminal of the inductive element is connected between the second switch and the first diode; and
a third switch and a second diode connected in series between the first output node and the second output node, wherein the second output terminal of the inductive element is connected between the third switch and the second diode;
wherein each of the second and third switches are operable to:
block voltage in two directions in an off state, and
conduct current in one direction in an on state.
2. The AC-DC converter of claim 1 , further comprising a control circuit configured to:
sense the AC input voltage, and
control the first, second, and third switches such that an input current substantially follows a waveform of the AC input voltage.
3. The AC-DC converter of claim 1 , wherein at least one of the second or third switches comprises a field-effect transistor (FET) in series with a diode.
4. The AC-DC converter of claim 3 , wherein either or both of the FET or the diode comprises at least one of silicon carbide (SiC) or gallium nitride (GaN).
5. The AC-DC converter of claim 1 , wherein the inductive element comprises a transformer.
6. The AC-DC converter of claim 1 , wherein the 4-Q switch comprises a first switch connected between the first and second nodes, wherein the first switch is operable to:
block voltage in two directions in an off state, and
conduct current in two directions in an on state.
7. The electrical circuit of claim 1 , wherein the 4-Q switch comprises:
a first FET coupled between the first node and a fourth node;
a second FET coupled between the second node and the fourth node;
a third diode coupled between the first node and the fourth node; and
a fourth diode coupled between the second node and the fourth node;
wherein an input of the first FET and an input of the second FET are configured to operate the 4-Q switch.
8. The electrical circuit of claim 1 , wherein the 4-Q switch comprises:
a third diode and a fourth diode coupled to the first node;
a fifth diode and a sixth diode coupled to the second node; and
a FET coupled between:
a node connecting the third diode with the fifth diode, and
a node connecting the fourth diode with the sixth diode;
wherein an input of the FET is configured to operate the 4-Q switch.
9. The electrical circuit of claim 1 , wherein:
the second inductive element comprises a coupled inductor having:
a first winding coupled between the second node and the third node; and
a second winding coupled between a fourth node and a fifth node;
wherein:
the first output of the second inductive element comprises the fourth node; and
the second output of the second inductive element comprises the fifth node.
10. A method of manufacturing an AC-DC converter comprising:
forming a coupled inductor operable to receive an AC input voltage and having first and second outputs connected to respective first and second nodes;
connecting a four-quadrant (4-Q) switch between the first and second nodes;
connecting a capacitor between the first node and a third node;
connecting an inductive element between the third node and the second node, the inductive element having a first output terminal and a second output terminal;
connecting a second switch and a first diode in series between a first output node and a second output node;
connecting the first output terminal of the inductive element between the second switch and the first diode;
connecting a third switch and a second diode in series between the first output node and the second output node;
connecting the second output terminal of the inductive element between the third switch and the second diode,
wherein each of the second and third switches are operable to:
block voltage in two directions in an off state, and
conduct current in one direction in an on state.
11. The method of claim 10 , wherein the 4-Q switch comprises a first switch connected between the first and second nodes, wherein the first switch is operable to:
block voltage in two directions in an off state, and
conduct current in two directions in an on state.
12. The method of claim 11 , further comprising connecting a control circuit to the first second, and third switches, wherein the control circuit is configured to:
sense the AC input voltage, and
control the first, second, and third switches such that an input current substantially follows a waveform of the AC input voltage.
13. The method of claim 10 , wherein at least one of the second or third switches comprises a field-effect transistor (FET) in series with a diode.
14. The method of claim 13 , wherein either or both of the FET or the diode comprises at least one of silicon carbide (SiC) or gallium nitride (GaN).
15. The method of claim 10 , wherein the inductive element comprises a transformer.
16. The method of claim 10 , wherein the 4-Q switch comprises:
a first FET coupled between the first node and a fourth node;
a second FET coupled between the second node and the fourth node;
a third diode coupled between the first node and the fourth node; and
a fourth diode coupled between the second node and the fourth node;
wherein an input of the first FET and an input of the second FET are configured to operate the 4-Q switch.
17. The method of claim 10 , wherein the 4-Q switch comprises:
a third diode and a fourth diode coupled to the first node;
a fifth diode and a sixth diode coupled to the second node; and
a FET coupled between:
a node connecting the third diode with the fifth diode, and
a node connecting the fourth diode with the sixth diode;
wherein an input of the FET is configured to operate the 4-Q switch.
18. The method of claim 10 , wherein:
the second inductive element comprises a coupled inductor having:
a first winding coupled between the second node and the third node; and
a second winding coupled between a fourth node and a fifth node;
wherein:
the first output of the second inductive element comprises the fourth node; and
the second output of the second inductive element comprises the fifth node.