TWO STAGE STRUCTURE FOR POWER DELIVERY ADAPTER

• US 20170170734A1
• Filed: 12/15/2015
• Published: 06/15/2017
• Est. Priority Date: 12/15/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: SHENG, Honggang, CHNG, Choon Ping
• Granted Patent: US 9,899,925 B2
• Time in Patent Office: Days
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/4258 using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• 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 3/33576 having at least one active switching element at the secondary side of an isolation transformer

Abstract

In one general aspect, a system can include an electromagnetic interference (EMI) filter, an alternating current (AC) rectifier bridge operatively coupled to the electromagnetic filter, the AC rectifier bridge providing a first voltage, a first power stage including a step-down transformer, the first power stage configured to receive the first voltage and output a second voltage, a second power stage configured to receive the second voltage and configured to convert the second voltage to a third voltage, and a power delivery adapter controller configured to receive at least one input indicative of a requested voltage value and configured to provide at least one output for use by the second power stage, the second power stage configured to determine a value for the third voltage based on the at least one output.

Claims

1. A system comprising:

an electromagnetic interference (EMI) filter;

an alternating current (AC) rectifier bridge operatively coupled to the electromagnetic filter, the AC rectifier bridge providing a first voltage;

a first power stage including a step-down transformer, the first power stage configured to receive the first voltage and output a second voltage;

a second power stage configured to receive the second voltage, the second power stage including a buck converter configured to convert the second voltage to a third voltage, the buck converter including at least one switch;

a power delivery adapter controller configured to receive at least one input indicative of a requested voltage value and configured to provide at least one output for use by the second power stage, the second power stage configured to determine a value for the third voltage based on the at least one output; and

a buck controller configured to control the switching of the at least one switch based on the determined value for the third voltage.

2. The system of claim 1, wherein an alternating current (AC) voltage is input to the electromagnetic filter, the AC voltage provided by an AC power source.

3. The system of claim 2,

wherein the step-down transformer includes a primary winding and a secondary winding,

wherein the primary winding includes a switch configured to control a number of windings on the primary winding, and

wherein a control signal for the switch enables the switch to control the number of windings on the primary winding based on a value for the AC voltage.

4. The system of claim 2,

wherein the step-down transformer includes a primary winding and a secondary winding,

wherein the secondary winding includes a switch configured to control a number of windings on the primary winding, and

wherein a control signal for the switch enables the switch to control the number of windings on the secondary winding based on a value for the AC voltage.

5. The system of claim 1, wherein the first voltage is a full-wave AC rectified voltage equal to a first voltage value and the second voltage is a lower AC rectified voltage equal to a second voltage value that is less than the first voltage value.

6. The system of claim 5, wherein the second voltage value is greater than the value for the third voltage.

7. The system of claim 1, wherein the step-down transformer functions as a safety isolation transformer.

8. The system of claim 1, wherein a first capacitor included on an input to the first power stage and a second capacitor included on an output of the first power stage determine an amount of AC ripple on the second voltage.

9. The system of claim 1, further including a feedback control circuit used to provide a feedback control input to the second power stage, wherein the at least one output for use by the second power stage controls a switch that switches a resistor in and out of the feedback control circuit, and wherein the second power stage is configured to determine a value for the third voltage based on the feedback control input.

11. The system of claim 1, wherein the power delivery adapter controller is configured to receive the at least one input indicative of a requested voltage value from a USB Type-C port.

10. (canceled)

12. A method for providing an output voltage comprising:

receiving an alternating current (AC) voltage from an AC power source;

generating a first voltage based on the AC voltage, the first voltage being a full-wave rectified voltage;

generating, by a first power stage, a second voltage based on the first voltage, the second voltage being a lower rectified voltage that is less than the first voltage;

receiving, by a power delivery adapter controller, at least one input indicative of a requested voltage value;

controlling, by the power delivery adapter controller, a feedback control signal based on the received at least one input indicative of the requested voltage value;

receiving, by a second power stage, the second voltage and the feedback control signal; and

generating, by the second power stage, an output voltage equal to the requested voltage value based on the received second voltage and the received feedback control signal.

13. The method of claim 12, wherein the controlling a feedback control signal based on the received at least one input indicative of the requested voltage value includes:

controlling switching of a first switch and a second switch, the first switch switching a first resistor in and out of a feedback control circuit used to generate the feedback control signal, and the second switch switching a second resistor in and out of the feedback control circuit.

14. The method of claim 13, further comprising:

providing, by a USB Type-C port, the at least one input indicative of a requested voltage value.

15. The method of claim 14,

wherein the USB Type-C port implements a USB power delivery (PD) protocol, and

wherein the controlling of the switching of the first switch and the second switch is based on the USB PD protocol.

16. The method of claim 12, wherein generating a second voltage based on the first voltage includes:

providing a control signal to a switch included on a primary winding of a step-down transformer included in the first power stage, the control signal enabling the switch to control a number of windings on the primary winding based on a value for the AC voltage.

17. The method of claim 12, wherein generating a second voltage based on the first voltage includes:

providing a control signal to a switch included on a secondary winding of a step-down transformer included in the first power stage, the control signal enabling the switch to control a number of windings on the secondary winding based on a value for the AC voltage.

18. The method of claim 12, wherein generating a first voltage based on the AC voltage includes:

inputting the AC voltage to an electromagnetic interference (EMI) filter;

suppressing, by the EMI filter, noise included on the AC voltage;

inputting the noise-suppressed AC voltage to an AC rectifier bridge; and

outputting, by the AC rectifier bridge, the full-wave rectified voltage as the first voltage.

19. A power adapter comprising:

a rectifier;

a cable including a plug connected to an alternating current (AC) power source, the AC power source providing an AC voltage to the rectifier;

a power delivery adapter controller;

a multipurpose port;

a buck controller; and

a two-stage adapter circuit including a first power stage and a second power stage, the second power stage including a buck converter including at least one switch;

the first power stage configured to receive a first voltage generated by the rectifier and based on the AC voltage, and configured to output a second voltage;

the second power stage configured to receive the second voltage, the buck converter configured to convert the second voltage to a third voltage; and

the power delivery adapter controller configured to receive at least one input indicative of a requested voltage value from the multipurpose port and configured to provide at least one output for use by the second power stage, the second power stage configured to determine a value for the third voltage based on the at least one output and configured to provide the third voltage to the multipurpose port; and

the buck controller configured to control the switching of the at least one switch based on the determined value for the third voltage.

20. The power adapter of claim 19, wherein the multipurpose port is a USB Type-C port that implements a USB power delivery (PD) protocol.