Logah Technology Corp.

Logan Technology Corp.

Teng-Ho Wu

Cheng-Chia Hsu

Yu-Cheng Pan

Ho-Wen Chen

Teng-Kang Chang

Chia-Yuan Chen

Jong-Chi Tseng

A double frequency signal generator to which a synchronization signal having a duty cycle of 1% to 999% is inputted. The synchronization signal is used for triggering of a switching component at positive and negative edges to generate a triangular-wave signal. An average of voltages of the triangular-wave signal is acquired and compared with the triangular-wave signal at a comparator to generate a square-wave having a duty cycle of 50%. Then, the square-wave signal is used for triggering at positive and negative edges to generate a double frequency signal. As such, the high cost issue and the limitation of a square-wave input signal occurred in the prior art may be efficiently overcome.

Double frequency signal generator

A bridge type phase detection device comprises one or more than one transformer, a plurality of tubes, a voltage-detecting protection circuit and a first, second and third impedance, wherein a first tube of said plurality of tubes has a phase opposite to that of a second tube of said plurality of tubes, and a first end of said first impedance coupling with a secondary side of said transformer and a first end of said first tube, a first end of said second impedance coupling with said secondary side of said transformer and a first end of said second tube, then a second end of said first impedance connecting to a second end of said second impedance to form a detection point, said detection point coupling with said third impedance and said voltage-detecting protection circuit; said detection point having a voltage value derived from calculating a sum of said phase of said first impedance and that of said second impedance, then an output voltage divided among said first, two and third impedance, resulting in approximately zero voltage at said detection point during normal operation, if said voltage-detecting protection circuit detecting a non-zero voltage, it is concluded that a tube anomaly is present.

Bridge type phase detection device

The invention discloses a feedback sampling control circuit for a lamp driving system having a feedback loop, in that the feedback sampling control circuit includes a switch and an effective current sampling controller. The switch is electrically coupled in the feedback path of the lamp driving system. The effective current sampling controller controls switching of the switch based on a voltage or current signal from a high voltage terminal of the lamp, such that an effective current actually sampled by a feedback controller in the lamp driving system is controlled so that a current component of a parasitic capacitance contained in the effective current is minimized. Thereby, the disadvantage caused by the leakage current through the parasitic capacitance can be eliminated and it is thus possible to precisely control the lamp current and to obtain a stable brightness quality.

Feedback sampling control circuit for lamp driving system

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Yongkang, Taiwan

Teng-Ho Wu