×

Wireless power transmitters with wide input voltage range and methods of their operation

  • US 9,843,219 B2
  • Filed: 11/04/2016
  • Issued: 12/12/2017
  • Est. Priority Date: 09/04/2013
  • Status: Active Grant
First Claim
Patent Images

1. A power transmitter for wirelessly charging an electronic device, the power transmitter comprising:

  • an input configured to receive a variable DC input voltage;

    an inverter coupled to the input to receive the variable DC input voltage, the inverter configured to generate an AC square-wave signal having a duty cycle selected to provide a predetermined equivalent voltage, wherein the inverter is configured to generate the AC square-wave signal with a relatively high duty cycle when a determined magnitude of the variable DC input voltage is relatively low, and the inverter is configured to generate the AC square-wave signal with a relatively low duty cycle when the determined magnitude of the variable DC input voltage is relatively high;

    a plurality of primary coils coupled to a matching network to receive a charging signal, the plurality of primary coils configured to be selectable in multiple different coil combinations, each of the multiple different coil combinations including a number of the plurality of primary coils, with at least one of the multiple different coil combinations including more than one of the plurality of primary coils to facilitate transmission with different numbers of primary coils, the plurality of primary coils configured to selectively transmit a power transfer signal to a receiver coil on the electronic device; and

    the matching network coupled to the inverter and to the plurality of primary coils, the matching network configured to generate the charging signal from the AC square-wave signal and to provide the charging signal to the plurality of primary coils, the matching network includinga differential input with first and second differential inputs configured to receive the AC square wave signal,a differential output with first and second differential outputs configured to produce the charging signal, anda plurality of switched capacitors that are selectively switched to achieve maximum power transfer efficiency for a selected coil combination used to transmit the power transfer signal, wherein the plurality of switched capacitors are coupled in parallel across the first and second differential inputs, wherein a first number of the plurality of switched capacitors are switched into the matching circuit when a first number of primary coils are included in the selected coil combination, and one or more additional switched capacitors are switched into the matching circuit when a second and larger number of primary coils are included in the selected coil combination.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×