SWITCHED MODE POWER SUPPLIES

• US 20140098578A1
• Filed: 10/01/2013
• Published: 04/10/2014
• Est. Priority Date: 10/05/2012
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: HALBERSTADT, Hans
• Granted Patent: US 9,219,419 B2
• Time in Patent Office: Days
• US Class Current: 363/21.15
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33515 with digital control
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An example embodiment relates to a switched-mode power supply comprising a transformer with a first winding and a second winding. There is a transmitter configured to: detect a detectable variable (Vout) at the first winding, generate a transformer relayed signal in accordance with the detectable variable (Vout), and provide the transformer relayed signal to the first winding. A receiver is configured to: receive the transformer relayed signal from the second winding, and control a controllable variable at the second winding in response to the transformer relayed signal, wherein the transformer relayed signal is a symbol stream comprising a plurality of symbols.

Claims

1. A switched-mode power supply comprising:

a transformer with a first winding and a second winding;

a transmitter configured to;

detect a detectable variable (Vout) at the first winding,

generate a transformer relayed signal in accordance with the detectable variable (Vout), and

provide the transformer relayed signal to the first winding; and

a receiver configured to;

receive the transformer relayed signal from the second winding, and

control a controllable variable at the second winding in response to the transformer relayed signal,

wherein the transformer relayed signal is a symbol stream comprising a plurality of symbols.

2. The switched-mode power supply of claim 1, wherein the first winding is a secondary side winding of the transformer and the second winding is a primary side winding of the transformer, the switched-mode power supply further comprising a power switch coupled in series with the primary side winding, wherein the controllable variable relates to a state of the power switch.

3. The switched-mode power supply of claim 2, further comprising a secondary side switch coupled in series with the secondary side winding, wherein the transmitter generates a transformer relayed signal by operating the secondary side switch.

4. The switched-mode power supply of claim 3, wherein the transmitter is configured to operate the secondary side switch during a ringing time in the operation of the switched-mode power supply.

5. The switched-mode power supply of claim 4, wherein the transmitter is configured to operate the secondary side switch at an instant at, or adjacent to, a maxima or minima in a voltage across the secondary winding during a ringing time in the operation of the switched-mode power supply.

6. The switched-mode power supply of claim 2, wherein the transmitter is configured to provide at least a portion of the symbol stream during a ringing time between a secondary stroke of a cycle and a primary stroke of a next cycle of the switched-mode power supply and to provide a further portion of the symbol stream during a ringing time between a secondary stroke of the next cycle or a subsequent cycle and a primary stroke of the cycle after the next or subsequent cycle.

7. The switched-mode power supply of claim 1, wherein the second winding is a secondary side winding of the transformer and the first winding is a primary side winding of the transformer, the switched-mode power supply further comprising a secondary side switch coupled in series with the secondary side winding, wherein the controllable variable relates to a state of the secondary side switch.

13. The switched-mode power supply of any preceding claim, wherein the detectable variable is indicative of one of:

a voltage, a power, or a current.

14. The switched-mode power supply of any preceding claim, wherein the transmitter is configured to provide the transformer relayed signal during a ringing time between a secondary stroke of a first cycle and a primary stroke of a next cycle of the switched-mode power supply.

15. The switched-mode power supply of claim 13, wherein the transformer relayed signal comprises an additional change of a current in, or voltage across, a winding of the transformer.

8. A switched-mode power supply comprising:

a transformer with a first winding and a second winding;

a communication current source associated with the first winding;

a transmitter associated with the first winding, the transmitter configured to operate the communication current source in order to adjust the voltage across the first winding in accordance with information to be communicated to the second winding, thereby generating a transformer relayed signal; and

a receiver associated with the second winding, the receiver configured to;

receive the transformer relayed signal from the second winding, and

control a controllable variable at the second winding in response to the transformer relayed signal.

9. The switched-mode power supply of claim 8, wherein the transmitter is configured to operate the communication current source in order to adjust the voltage across the first winding during a ringing time between a secondary stroke of a cycle and a primary stroke of a next cycle of the switched-mode power supply.

10. The switched-mode power supply of claim 8, wherein the first winding is a primary winding and the second winding is a secondary winding, and further comprising a secondary side switch in series with the secondary winding, wherein the receiver is configured to control the state of the secondary side switch in order to close the secondary side switch before the start of a primary stroke of the switched mode power supply in accordance with the transformer relayed signal.

11. The switched-mode power supply of claim 8, wherein the current source is configured to provide an alternating current with a carrier frequency, and the transmitter is configured to modulate the carrier frequency in accordance with information to be communicated to the second winding in order to provide the transformer relayed signal.

12. A switched-mode power supply comprising:

a transformer with a primary side winding and a secondary side winding;

a secondary side switch coupled in series with the secondary side winding;

a transmitter configured to;

detect a detectable variable at the primary side winding,

generate a transformer relayed signal in accordance with the detectable variable, and

provide the transformer relayed signal to the primary side winding; and

a receiver configured to;

receive the transformer relayed signal from the secondary side winding, and

operate the secondary side switch in response to the transformer relayed signal.