Class E amplifier overload detection and prevention

• US 8,736,368 B2
• Filed: 03/30/2012
• Issued: 05/27/2014
• Est. Priority Date: 08/16/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Irish, Linda S, Toncich, Stanley Slavko, Von Novak, William H III
• Primary Examiner(s): Mottola, Steven J
• Application Number:
  US13/436,650
• Publication Number:
  US 20130043951A1
• Time in Patent Office: 788 Days
• Field of Search: 330/51, 330/251, 330/298
• US Class Current: 330/251
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H03F 1/523 for amplifiers using field-effect devices H03F1/526 takes precedence
• CPC Class Codes: H03F 3/2176 Class E amplifiers
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• 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

Systems, methods and apparatus are disclosed for amplifiers for wireless power transfer. In one aspect a method is provided for controlling operation of an amplifier, such as a class E amplifier. The method may include monitoring an output of the amplifier. The method may further include adjusting a timing of an enabling switch of the amplifier based on the output of the amplifier.

Claims

1. A method of controlling operation of an amplifier comprising:

monitoring an output of an enabling switch of the amplifier;

adjusting a timing of the enabling switch based on the output;

enabling the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point; and

enabling the enabling switch when the output does not fall below the first threshold within a time limit.

2. The method of claim 1, wherein the amplifier comprises is configured as a class E amplifier.

3. The method of claim 1, wherein the output has a falling edge, the adjusting comprising substantially aligning a rising edge of an enabling signal supplied to the enabling switch to the falling edge.

4. The method of claim 1, wherein the output has a falling edge, the adjusting comprising substantially aligning a falling edge of an enabling signal supplied to the enabling switch to the falling edge.

5. An apparatus for controlling operation of an amplifier comprising:

means for monitoring an output of an enabling switch of the amplifier;

means for adjusting a timing of the enabling switch based on the output;

means for enabling the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point; and

means for enabling the enabling switch when the output does not fall below the first threshold within a time limit.

6. The apparatus of claim 5, wherein the amplifier is configured as a class E amplifier.

7. The apparatus of claim 5, wherein the output has a falling edge, the means for adjusting comprising means for substantially aligning a rising edge of an enabling signal supplied to the enabling switch to the falling edge.

8. The apparatus of claim 5, wherein the output has a falling edge, the means for adjusting comprising means for substantially aligning a falling edge of an enabling signal supplied to the enabling switch to the falling edge.

9. A non-transitory computer-readable medium comprising code that, when executed, causes an apparatus to:

monitor an output of an enabling switch of an amplifier;

adjust a timing of the enabling switch based on the output; and

enable the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point; and

enable the enabling switch when the output does not fall below the first threshold within a time limit.

10. The medium of claim 9, wherein the amplifier is configured as a class E amplifier.

11. The medium of claim 9, wherein the output has a falling edge, and the medium further comprises code that, when executed, causes the apparatus to substantially align a rising edge of an enabling signal supplied to the enabling switch to the falling edge.

12. The medium of claim 9, wherein the output has a falling edge, and the medium further comprises code that, when executed, causes the apparatus to substantially align a falling edge of an enabling signal supplied to the enabling switch to the falling edge.

13. An apparatus configured to transmit wireless charging power, the apparatus comprising:

an amplifier comprising an enabling switch;

a monitoring circuit configured to monitor an output of the enabling switch;

a timing circuit configured to adjust a timing of the enabling switch based on the output; and

a driving circuit configured to enable the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point and enable the enabling switch when the output does not fall below the first threshold within a time limit.

14. The apparatus of claim 13, wherein the amplifier is configured as a class E amplifier.

15. The apparatus of claim 13, wherein the output has a falling edge, the timing circuit configured to substantially align a rising edge of an enabling signal supplied to the enabling switch to the falling edge.

16. The apparatus of claim 13, wherein the output has a falling edge, timing circuit configured to substantially align a falling edge of an enabling signal supplied to the enabling switch to the falling edge.

17. A method of controlling operation of an amplifier comprising:

monitoring an output of an enabling switch of the amplifier;

adjusting a timing of the enabling switch based on the output; and

enabling the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point,

wherein;

the monitoring comprises measuring an antenna current divided by a DC power value, and

the adjusting comprises adjusting a duty cycle of the enabling switch based on the antenna current divided by the DC power value.

18. An apparatus for controlling operation of an amplifier comprising:

means for monitoring an output of an enabling switch of the amplifier;

means for adjusting a timing of the enabling switch based on the output; and

means for enabling the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point,

wherein;

the means for monitoring comprises means for measuring an antenna current divided by a DC power value, and

the means for adjusting comprising means for adjusting a duty cycle of the enabling switch based on the antenna current divided by the DC power value.

19. A non-transitory computer-readable medium comprising code that, when executed, causes an apparatus to:

monitor an output of an enabling switch of an amplifier;

adjust a timing of the enabling switch based on the output;

enable the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point;

measure an antenna current divided by a DC power value; and

adjust a duty cycle of the enabling switch based on the antenna current divided by the DC power value.

20. An apparatus configured to transmit wireless charging power, the apparatus comprising:

an amplifier comprising an enabling switch;

a monitoring circuit configured to monitor an output of the enabling switch;

a timing circuit configured to adjust a timing of the enabling switch based on the output; and

a driving circuit configured to enable the enabling switch when the output of the enabling switch falls below a first threshold above a zero crossover point,

wherein the monitoring circuit comprises a drain power detector and an antenna current detector, the timing circuit configured to adjust a duty cycle of the enabling switch based on the antenna current divided by the DC power value.