Specific phase position detection circuit and method of the same

A specific phase position detection circuit that detects a time position to have a specific phase as a specific phase position in each cycle of an analog signal,

• the specific phase position detection circuit comprising:
• a first detection unit that detects a time position where a signal level of the analog signal is matched with a preset threshold value, as a reference position;
• a measurement unit that measures a time length based on the detected reference position, as a reference time period;
• a computation unit that computes a time period at a preset rate to the measured reference time period, as an additional time period;
• and
• a second detection unit that detects a time position based on the detected reference position and the computed additional time period, as the specific phase position, and outputs a detection signal representing the detected specific phase position.

A specific phase position detection circuit that detects a time position to have a specific phase as a specific phase position in each cycle of an analog signal,

• the specific phase position detection circuit comprising:
• a measurement unit that detects two time positions where a signal level of the analog signal is matched with a preset first threshold value, as a first reference position and a second reference position in each cycle of the analog signal, and measures a time length between the first reference position and the second reference position, as a reference time period;
• a computation unit that computes a time period at a preset rate to the reference time period measured in each previous cycle, as an additional time period in each current cycle of the analog signal;
• and
• a detection unit that detects a time position shifted from the first reference position detected in a current cycle by the additional time period computed by the computation unit, as the specific phase position, and outputs a detection signal representing the detected specific phase position.

A specific phase position detection method that detects a time position to have a specific phase as a specific phase position in each cycle of an analog signal,

• the specific phase position detection method comprising the steps of:
• (a) detecting two time positions where a signal level of the analog signal is matched with a preset threshold value, as a first reference position and a second reference position in each cycle of the analog signal;
• (b) measuring a time length between the first reference position and the second reference position, as a reference time period;
• (c) computing a time period at a preset rate to the reference time period measured in each previous cycle, as an additional time period in each current cycle of the analog signal;
• and
• (d) detecting a time position shifted from the first reference position detected in a current cycle by the additional time period, as the specific phase position.