Granted Patent B2

US 12,438,469 · App. 17/311,083 · Granted Oct 7, 2025

Inventors: Alexander Moser (Werl, DE); Thomas Sprink (Salzkotten, DE)

Assignee: Phoenix Contact GmbH & Co. KG

H02M3/33569H02M1/0074H02M1/0077H02M3/158H02M1/007

Abstract

Claims (40)

1. A switched-mode power supply, comprising:

an input circuit powered by an input voltage, wherein the input voltage is based on a voltage difference between a positive input voltage and a negative input voltage;

an output circuit coupled to the input circuit and configured to provide an output voltage; and

a direct current (DC) isolating element between the input circuit and the output circuit and configured to observe a prescribed safety requirement with regard to isolation between the input voltage and the output voltage,

wherein the input circuit comprises two coupled step-down converter stages, wherein the two coupled step-down converter stages comprise a first step-down converter stage configured to step down the positive input voltage and a second step-down converter stage configured to step down the negative input voltage, wherein the two coupled step-down converter stages are connected to the input circuit upstream of the DC isolating element,

wherein the two coupled step-down converter stages are configured to cause a voltage drop in the input voltage and thus reduce an isolation voltage across the DC isolating element,

wherein the two coupled step-down converter stages are coupled to one another on an output side via an output capacitor,

wherein a coil of the first step-down converter stage and a coil of the second step-down converter stage are wound on and coupled via a common core,

wherein the two coupled step-down converter stages are configured to be controlled jointly via a control signal,

wherein the input circuit comprises a control circuit configured to generate the control signal, and

wherein a reference potential of the control circuit is associated with a center tap between the two coupled step-down converter stages.

2. The switched-mode power supply according to claim 1 ,

wherein the switched-mode power supply is grounded to the positive input voltage or to the negative input voltage.

3. The switched-mode power supply according to claim 1 ,

wherein each of the two coupled step-down converter stages further comprises a power switch and a free-wheeling diode.

4. The switched-mode power supply according to claim 3 ,

wherein the input circuit comprises a pulse transformer or a driver circuit configured to adapt the control signal of the two coupled step-down converter stages to a reference potential of both power switches.

5. The switched-mode power supply according to claim 3 ,

wherein the two coupled step-down converter stages are coupled to one another on an input side via two input capacitors connected in series, wherein a center tap of the two input capacitors forms the center tap between the two coupled step-down converter stages.

6. The switched-mode power supply according to claim 5 ,

wherein the two input capacitors are connected in series between the positive input voltage and the negative input voltage.

7. The switched-mode power supply according to claim 3 ,

wherein the DC isolating element comprises a transformer configured to be controlled by the control circuit via a second power switch.

8. The switched-mode power supply according to claim 7 ,

wherein the input circuit comprises a second transformer connected between the control circuit and the power switch, wherein the second transformer galvanically isolates the control circuit from the power switch.

9. The switched-mode power supply according to claim 3 ,

wherein the DC isolating element comprises a feedback element configured to regulate the input circuit, wherein the feedback element is configured to be controlled by a secondary-side regulator.

10. A method for reducing an insulation requirement on a switched-mode power supply, comprising:

providing an input circuit powered by an input voltage, wherein the input voltage is based on a difference between a positive input voltage and a negative input voltage, an output circuit coupled to the input circuit and configured to provide an output voltage, and a DC isolating element between the input circuit and the output circuit, wherein the DC isolating element is configured to comply with a prescribed safety requirement with regard to isolation between the input voltage and the output voltage; and

switching two coupled step-down converter stages in the input circuit of the switched-mode power supply,

wherein the two coupled step-down converter stages comprise a first step-down converter stage in the positive input voltage and a second step-down converter stage in the negative input voltage, wherein the two coupled step-down converter stages are connected to the input circuit upstream of the DC isolating element,

wherein the two coupled step-down converter stages are configured to cause a voltage drop in the input voltage and thus reduce an isolation voltage across the DC isolating element,

wherein the two coupled step-down converter stages are coupled to one another on an output side via an output capacitor,

wherein a coil of the first step-down converter stage and a coil of the second step-down converter stage are wound on and coupled via a common core,

wherein the method further comprises controlling the two coupled step-down converter stages jointly via a common control signal,

wherein the input circuit comprises a control circuit configured to generate the common control signal, and

wherein a reference potential of the control circuit is associated with a center tap between the two coupled step-down converter stages.

11. The method of claim 10 , further comprising:

adapting a control signal of the two coupled step-down converter stages to a reference potential of respective power switches of the two coupled step-down converter stages.

12. The method of claim 11 , wherein the two coupled step-down converter stages are coupled to one another on an input side via two input capacitors connected in series, wherein a center tap of the two input capacitors forms the center tap between the two coupled step-down converter stages.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (26)