Patent ID: 7804197

Claim:
A power transmission control device provided in a power transmission device included in a non-contact power transmission system, the non-contact power transmission system transmitting power from the power transmission device to a power reception device by electromagnetically coupling a primary coil and a secondary coil to transmit the power to a load of the power reception device, the power transmission control device comprising: a drive clock signal generation circuit that generates a drive clock signal that specifies a drive frequency of the primary coil; a driver control circuit that generates a driver control signal based on the drive clock signal, and outputs the driver control signal to a transmission driver that drives the primary coil; a waveform detection circuit that detects a waveform of an induced voltage signal of the primary coil; and a control circuit that detects a power-reception-side load state based on a detection result of the waveform detection circuit, the waveform detection circuit including a first pulse width detection circuit that measures a first pulse width period to detect first pulse width information, the first pulse width period being a period between a first edge timing of the drive clock signal and a first timing, the first timing being a timing when a first induced voltage signal of the primary coil that has changed from a low-potential-side power supply voltage exceeds a first threshold voltage; and the control circuit detecting the power-reception-side load state based on the first pulse width information.