Abstract: The LEDs in a phototherapy LED pad are controlled so that the intensity of the light varies in accordance with a sinusoidal function, thereby eliminating the harmonics that are generated when the LEDs are pulsed digitally, in accordance with a square-wave function. This is accomplished analogically by using a sinusoidal wave to control the gate of a MOSFET connected in series with the LEDs or by using a digital-to-analog converter to control the gate of the MOSFET with a stair step function representative of the values of a sinusoidal function at predetermined intervals. Alternatively, pulse-width modulation is used to control the gate of the MOSFET in such a way that the average current through the LEDs simulates a sinusoidal function. In additional to using a simple sine wave function, the LED current may also be controlled in accordance with “chords” containing multiple sine waves of different frequencies.

Abstract: In a flexible LED pad for use in phototherapy treatment of humans or animals, the PCBs in the pad are securely linked together with electrical connectors and ribbon cables to prevent the connections from being broken as the flexible pad is bent or otherwise deformed during the treatment. In one embodiment, low-profile socket connectors are mounted to the PCBs and mate with plug connectors at the ends of the ribbon cables. For similar reasons, the LED pad may be connected to an LED control unit by means of an electrical connector (e.g. a USB socket) mounted to a PCB in the LED pad. The PCBs, on which the LEDs are mounted, are fitted into a downset in the flexible pad to prevent the LEDs from becoming misaligned with openings in the flexible pad.