A resonant voltage multiplier for long-range inductive power transmission

A switch-based technique has been presented for efficient inductive power transmission at large coupling distances. Unlike the conventional inductive link, in which the receiver (Rx) LC-tank is utilized as a voltage source, the proposed link switches the Rx LC-tank in a novel fashion to act as a current source. Therefore, the voltage across the load (RL) can be significantly larger than the Rx LC-tank voltage. This enables the design of integrated voltage multipliers without additional off-chip capacitors and diodes, which are needed in conventional voltage multipliers. In the proposed link, the energy is first stored in the Rx coil by shorting the Rx LC-tank for several power carrier cycles. At the peak of Rx coil current, the coil energy is then transferred to the load capacitance and RL. In simulations, the proposed inductive link was capable of achieving a DC voltage of 5.7 V across RL of 100 kΩ while the peak of maximum AC voltage across the Rx coil was 1 V at the operation frequency of 1 MHz.