Abstract: A two-mode DC/DC converter systems, for use in wireless power transmission receivers, and which allow the use of conventional logic circuits, operating at voltages well over IV, to efficiently drive DC/DC converter circuits even while being powered from the low voltage, even below IV, of a photovoltaic cell output. Two separate control modules may control the DC/DC converter, a first using a simple control for switching the converter, capable of being powered by the low voltages generated by the PV. Once a voltage above about 1.5V is generated at the output of the DC/DC converter, a second, more complex controller can become powered up, and takes control of the voltage conversion process, driving the converter more efficiently, and able to adapt its control function according to logical input instructions and sensor outputs received. The complex controller can operate independently, or in conjunction with the simple controller, to increase efficiency further.

Abstract: New systems for ensuring the reliable function of systems for laser powering and information propagation using receivers located in premises frequented by the public, such as a store or a public office, using information displays. The systems employ a wireless power transmitter which has a detector for determining whether the premises is operating in a situation characteristic of normal working hours, with people present who may interfere with its correct operation, or whether the situation is typical of closed premises, with low or zero occupancy, enabling the system to operate reliably in what may be termed an “after-hours” mode. Operations which must be performed reliably include charging the receivers, updating of the displays, maintenance of the devices, and software updates. The system can detect the presence of human activity directly, or by implication by the cessation of services such as lighting or air conditioning in the area.