# US 10,122,287 B2 · Power supply systems and feedback through a transformer

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- Number: US 10,122,287 B2
- Document ID: US10122287B2
- Status: Granted
- Kind: B2
- Application number: 15/190,658
- Filed: 2016-06-23
- Published: 2017-08-24
- Granted: 2018-11-06
- Earliest claimed: 2016-02-24
- Assignees: Infineon Technologies Austria AG
- Applicants: Infineon Technologies Austria AG
- Inventors: Kennith K. Leong; Arash Pake Talei; Gerald Deboy; Giuseppe Bernacchia
- Web page: https://patentgrep.com/patent/US10122287B2

## CPC

- H02M 3/33592: {having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer}
- H02M 3/33523: {with galvanic isolation between input and output of both the power stage and the feedback loop}
- 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
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A power converter circuit includes a transformer. The transformer includes a primary winding and a secondary winding. A primary circuit is coupled to the primary winding. A secondary circuit is coupled to the secondary winding. The primary circuit and the secondary circuit are referenced to different ground voltage potentials that may vary with respect to each other. During operation, the primary circuit controls input of energy to the primary winding of the transformer. The secondary circuit receives the energy through the secondary winding and uses it to produce an output voltage to power a load. The secondary circuit receives and/or generates state information at one of multiple different levels. The secondary circuit controls a flow of current through the secondary winding to convey the state information as feedback to the primary circuit. The primary circuit analyzes a voltage at a node of the primary winding to receive the feedback.

## Claims

### Claim 1

An apparatus comprising: a transformer including a primary winding and a secondary winding; a primary circuit to control input of energy to the primary winding of the transformer; a secondary circuit to control receiving the energy through the secondary winding of the transformer and produce an output voltage from the received energy; the secondary circuit operable to control a timing of conveying feedback through the secondary winding to the primary winding to maintain a magnitude of the output voltage within a desired range; and the primary circuit operable to measure the timing of receiving the conveyed feedback at the primary winding with respect to a reference time value and use the measured timing to control the input of energy to the primary winding; wherein the primary circuit includes a timer, the primary circuit further operable to: during a first cycle of inputting energy to the primary winding and receiving the energy through the secondary winding: start a timer to track passage of time; and use the timer to determine a time of receiving the feedback at the primary winding.

### Claim 2 (depends on 1)

The apparatus as in claim 1, wherein the secondary circuit delays the timing of conveying the feedback through the secondary winding to the primary winding until a time of detecting that the magnitude of the output voltage crosses a threshold value.

### Claim 3 (depends on 1)

The apparatus as in claim 1, wherein the secondary circuit is operable to:
monitor the magnitude of the output voltage; and
in response to detecting that the magnitude of the output voltage differs with respect to a setpoint reference voltage above a threshold difference value, communicate the feedback through the secondary winding to the primary winding.

### Claim 4 (depends on 3)

The apparatus as in claim 3, wherein the primary circuit adjusts a pulse duration of energizing the primary winding on a subsequent cycle in response to receiving the feedback.

### Claim 5 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is operable to control a flow of current through the primary winding of the transformer to store the energy in the transformer; and
wherein the secondary circuit is operable to control a flow of current through the secondary winding of the transformer to receive the energy and produce the output voltage subsequent to completion of inputting the energy through the primary winding.

### Claim 6 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is operable to adjust a frequency of inputting energy into the primary winding over multiple cycles depending on times of receiving the feedback; and
wherein the secondary circuit is operable to, in response to detecting the input of the energy into the primary winding, synchronously receive the energy via control of current through the secondary winding.

### Claim 7 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is further operable to decrease the pulse duration of energizing the primary winding on a second cycle with respect to a magnitude of a pulse duration of energizing the primary winding on the first cycle to maintain frequency operation of energizing the primary winding over multiple cycles to be above a frequency threshold value.

### Claim 8 (depends on 7)

The apparatus as in claim 7, wherein the primary circuit is further operable to:
compare the time of receiving the feedback at the primary winding to a setpoint time value, the setpoint time value corresponding to a desired fixed frequency of inputting energy into the primary winding over multiple cycles; and
in response to detecting that the time is substantially equal to the setpoint time value, set a magnitude of the pulse duration of energizing the primary winding on the second cycle to be substantially the same as a pulse duration of energizing the primary winding on the first cycle.

### Claim 9 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is further operable to:
produce a difference value indicating a time difference between the time of receiving the feedback and a setpoint time value, the setpoint time value corresponding to a desired fixed frequency of inputting energy into the primary winding over multiple cycles; and
use the difference value to proportionally adjust a magnitude of a pulse duration of energizing the primary winding on a second cycle with respect to a magnitude of a pulse duration of energizing the primary winding on the first cycle.

### Claim 10 (depends on 1)

The apparatus as in claim 1, wherein the feedback includes state information indicating a particular state selected amongst multiple possible states, the feedback varying depending on a magnitude of error between the output voltage and a desired setpoint.

### Claim 11 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is further operable to utilize the feedback to determine a magnitude in which to adjust a pulse duration of energizing the primary winding for a subsequent cycle of energizing the primary winding.

### Claim 12 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is further operable to adjust a pulse duration of energizing the primary winding depending on the measured timing of receiving the feedback at the primary winding.

### Claim 13 (depends on 12)

The apparatus as in claim 12, wherein adjustment of the pulse duration changes a switching frequency of energizing the primary winding.

### Claim 14 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit includes a timer circuitry operable to measure a time delay of receiving the feedback at the primary winding.

### Claim 15 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is operable to control a switching frequency of energizing the primary winding based on the measured timing of the conveyed feedback.

### Claim 16 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit switches between operating in a fixed frequency mode and a variable frequency mode of inputting energy into the primary winding based on the measured timing of receiving the feedback with respect to the reference time value over each of multiple cycles.

### Claim 17 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is operable to adjust a pulse duration of energizing the primary winding based on power consumption of a load powered by the output voltage.

### Claim 18 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is further operable to:
determine a time difference between the time of receiving the feedback at the primary winding and the reference time value; and
utilize the time difference to determine a pulse duration of energizing the primary winding.

### Claim 19 (depends on 18)

The apparatus as in claim 18, wherein the reference time value varies depending on a desired frequency of inputting the energy into the primary winding over multiple cycles.

### Claim 20 (depends on 1)

The apparatus as in claim 1, wherein the primary circuit is operable to control a pulse duration of energizing the primary winding over multiple cycles based on the timing of receiving the feedback at the primary winding, the pulse duration controlled to maintain a frequency of inputting the energy into the primary winding at a desired frequency.

### Claim 21

A method comprising: controlling operation of a power converter circuit to input energy to a primary winding of a transformer and receive the energy through a secondary winding of the transformer; producing an output voltage using the energy received through the secondary winding; controlling a timing of conveying feedback through the secondary winding to the primary winding to maintain a magnitude of the output voltage within a desired range; monitoring the timing of receiving the feedback at the primary winding; controlling a pulse duration of energizing the primary winding depending on the timing of receiving the feedback at the primary winding; and the method further comprising: during a first cycle of inputting energy to the primary winding and receiving the energy through the secondary winding: i) starting a timer to track a passage of time, and ii) use the timer to determine a time of receiving the feedback at the primary winding.

### Claim 22 (depends on 21)

The method as in claim 21, wherein controlling the timing includes:
delaying the timing of conveying the feedback through the secondary winding to the primary winding until a time of detecting that the magnitude of the output voltage crosses a threshold value.

### Claim 23 (depends on 21)

The method as in claim 21, wherein controlling the timing includes:
monitoring the magnitude of the output voltage; and
in response to detecting that the magnitude of the output voltage differs with respect to a setpoint reference voltage above a threshold difference value, communicating the feedback through the secondary winding to the primary winding.

### Claim 24 (depends on 23)

The method as in claim 23 further comprising:
in response to receiving the feedback, adjusting the pulse duration of energizing the primary winding on a subsequent cycle.

### Claim 25 (depends on 21)

The method as in claim 21, wherein controlling operation of the power converter circuit further comprises:
controlling a flow of current through the primary winding of the transformer to store the energy in the transformer; and
subsequent to completion of inputting the energy through the primary winding, controlling a flow of current through the secondary winding of the transformer to receive the energy and produce the output voltage.

### Claim 26 (depends on 21)

The method as in claim 21 further comprising:
adjusting a frequency of inputting energy into the primary winding over multiple cycles depending on times of receiving the feedback; and
in response to detecting the input of the energy into the primary winding, synchronously receiving the energy via control of current through the secondary winding.

### Claim 27 (depends on 21)

The method as in claim 21 further comprising:
decreasing the pulse duration of energizing the primary winding on a second cycle with respect to a magnitude of a pulse duration of energizing the primary winding on the first cycle to maintain frequency operation of energizing the primary winding over multiple cycles to be above a frequency threshold value.

### Claim 28 (depends on 27)

The method as in claim 27 further comprising:
comparing the time of receiving the feedback at the primary winding to a setpoint time value, the setpoint time value corresponding to a desired fixed frequency of inputting energy into the primary winding over multiple cycles; and
in response to detecting that the time is substantially equal to the setpoint time value, setting a magnitude of the pulse duration of energizing the primary winding on the second cycle to be substantially the same as a pulse duration of energizing the primary winding on the first cycle.

### Claim 29 (depends on 21)

The method as in claim 21 further comprising:
comparing the time to a setpoint time value, the setpoint time value corresponding to a desired fixed frequency of inputting energy into the primary winding over multiple cycles; and
depending on the comparison, adjusting a magnitude of a pulse duration of energizing the primary winding on a second cycle with respect to a magnitude of a pulse duration of energizing the primary winding on the first cycle.

### Claim 30 (depends on 29)

The method as in claim 29, wherein adjusting the magnitude further comprises:
in response to detecting that the time is less than the setpoint time value, increasing the pulse duration of energizing the primary winding on the second cycle with respect to a magnitude of the pulse duration of energizing the primary winding on the first cycle.

### Claim 31 (depends on 29)

The method as in claim 29, wherein adjusting the magnitude further comprises:
in response to detecting that the time is greater than the setpoint time value, decreasing the pulse duration of energizing the primary winding on the second cycle with respect to a magnitude of the pulse duration of energizing the primary winding on the first cycle.

### Claim 32 (depends on 21)

The method as in claim 21 further comprising:
producing a difference value indicating a time difference between the time of receiving the feedback and a setpoint time value, the setpoint time value corresponding to a desired fixed frequency of inputting energy into the primary winding over multiple cycles; and
using the difference value to proportionally adjust a magnitude of a pulse duration of energizing the primary winding on a second cycle with respect to a magnitude of a pulse duration of energizing the primary winding on the first cycle.

### Claim 33 (depends on 21)

The method as in claim 21, wherein the feedback includes state information indicating a particular state selected amongst multiple possible states, the feedback varying depending on a magnitude of error between the output voltage and a desired setpoint.

### Claim 34 (depends on 21)

The method as in claim 21 further comprising:
utilizing the feedback to determine a magnitude in which to adjust the pulse duration of energizing the primary winding for a subsequent cycle of energizing the primary winding.

### Claim 35 (depends on 21)

The method as in claim 21 further comprising:
measuring the timing of receiving the conveyed feedback at the primary winding with respect to a reference time value; and
using the measured timing as a basis to control the pulse duration.

### Claim 36

An apparatus comprising:
a transformer including a primary winding and a secondary winding;
a primary circuit to control input of energy to the primary winding of the transformer;
a secondary circuit to control receiving the energy through the secondary winding of the transformer and produce an output voltage from the received energy;
the secondary circuit operable to control a timing of conveying feedback through the secondary winding to the primary winding to maintain a magnitude of the output voltage within a desired range;
wherein the primary circuit includes a timer, the primary circuit further operable to: during a first cycle of inputting energy to the primary winding and receiving the energy through the secondary winding: i) start a timer to track passage of time; and ii) use the timer to determine a time of receiving the feedback at the primary winding;
wherein the primary circuit is further operable to:
compare the time to a setpoint time value, the setpoint time value corresponding to a desired fixed frequency of inputting energy into the primary winding over multiple cycles; and
depending on the comparison, adjust a magnitude of a pulse duration of energizing the primary winding on a second cycle with respect to a magnitude of a pulse duration of energizing the primary winding on the first cycle.

### Claim 37 (depends on 36)

The apparatus as in claim 36, wherein the primary circuit is further operable to:
in response to detecting that the time is less than the setpoint time value, increase the pulse duration of energizing the primary winding on the second cycle with respect to a magnitude of the pulse duration of energizing the primary winding on the first cycle.

### Claim 38 (depends on 36)

The apparatus as in claim 36, wherein the primary circuit is further operable to:
in response to detecting that the time is greater than the setpoint time value, decrease the pulse duration of energizing the primary winding on the second cycle with respect to a magnitude of the pulse duration of energizing the primary winding on the first cycle.