Class E amplifier overload detection and prevention
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.
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.