Power transmission device and wireless power transfer system

A power transmission device included in a wireless power transfer system that includes the power transmission device and a power reception device and in which power is supplied from the power transmission device to the power reception device, the power reception device including a power reception coil, a power-reception resonance capacitor that forms a power-reception resonance mechanism with the power reception coil and a power reception circuit that is electrically connected to the power-reception resonance mechanism and that supplies power to a load, the power transmission device comprising:

• a power transmission coil;
• a power-transmission resonance capacitor that forms, together with the power transmission coil, a power-transmission resonance mechanism;
• and
• a power transmission circuit that is electrically connected to the power-transmission resonance mechanism and that is configured to intermittently apply a direct-current input voltage to the power-transmission resonance mechanism and cause the power transmission coil to generate an alternating-current voltage, the power transmission circuit including a control circuit section and a power circuit section, each of which is formed of an electronic circuit, the power circuit section being formed of an integrated circuit sealed in a package with a plurality of terminals, the integrated circuit being electrically and directly connected to the power-transmission resonance mechanism, the control circuit section being configured to output a driving signal to the power circuit section, and the power circuit section being configured to drive, by using the driving signal input to the power circuit section, a transistor provided in the integrated circuit, to intermittently apply the direct-current input voltage to the power-transmission resonance mechanism,
• wherein
• at least a portion of the control circuit section and at least a portion of the power circuit section are formed of a complementary metal oxide semiconductor (CMOS) standard logic integrated circuit (IC) or a transistor-transistor logic (TTL) standard logic IC that includes a plurality of logic gate circuits and that is sealed in a single package with a plurality of terminals,
• the CMOS standard logic IC or the TTL standard logic IC includes four two-input NAND gates, and
• the control circuit section includes an oscillation circuit that includes one of the four NAND gates and an oscillator, and the power circuit section includes the remaining NAND gates among the four NAND gates.