High-efficiency power amplifier system for wireless power transmitters

A device for providing wireless power comprising:

• a power supply;
• a power amplifier coupled to the power supply, the power amplifier comprising:
• a first switch and a second switch coupled to the power supply and to a common switch output,
• a first diode coupled between an output of the first switch and an input of the first switch, the first diode biased to enable current flow from the output to the input of the first switch,
• a second diode coupled between an output of the second switch and an input of the second switch, the second diode biased to enable current flow from the output to the input of the second switch;
• and
• a pulse-width modulator (“PWM”) coupled to the power amplifier, the PWM configured to substantially simultaneously toggle each of the first and second switches between open and closed states, and to maintain the first and second switches in opposite open and closed states;
• a controller coupled to the power supply and the PWM, the controller configured to:
• receive a sensor signal indicating an impedance of a load;
• determine a duty cycle of the PWM based on the sensor signal;
• and
• adjust an output voltage of the power supply based on the duty cycle of the PWM.