Transmitting type electronic pen and signal transmitting circuit thereof

A transmitting type electronic pen comprising:

• a housing;
• and
• a signal transmitting circuit disposed in the housing,
• wherein the signal transmitting circuit includes:
• a resonance circuit including a coil and a resonance capacitor;
• a switch circuit which, in operation, enables a current to flow to the resonance circuit, the current providing to the resonance circuit energy that sustains resonance of the resonance circuit;
• and
• a control signal generating circuit which, in operation, generates a control signal that controls changeover of the switch circuit to enable the current to flow to the resonance circuit,
• wherein the control signal generating circuit includes:
• a detection circuit which, in operation, detects a cycle of the transmission signal;
• a timing generating circuit which, in operation, generates a timing point at which the control signal is generated based on a result of a detection by the detection circuit;
• and
• a drive circuit which, in operation, generates the control signal at a timing point generated by the timing generating circuit and supplies the generated control signal to the switch circuit;
• and
• wherein a transmission signal with a resonance frequency of the resonance circuit is output from the electronic pen.