TRIANGULAR WAVEFORM GENERATING CIRCUIT, GENERATING METHOD, INVERTER USING THEM, LIGHT EMITTING DEVICE AND LIQUID CRYSTAL TELEVISION

摘要

A charging/discharging circuit (32) charges or discharges a capacitor (C2) having an end the potential at which is fixed. A first comparator (COMP1) compares an output voltage (Vout) of the capacitor (C2) with a first threshold voltage (Vmin) to output a first comparison signal (S1) in accordance with a comparison result. An edge detecting circuit (34) detects the edges of an externally applied synchronization signal (SYNC_IN), the frequency of which is equal to approximately a half of a triangular waveform signal generated by the triangular waveform generating circuit (30), and outputs an edge detection signal (S4) that exhibits a predetermined level for each of the detected edges. A charging/discharging control part (40) refers to both the first comparison signal (S1) outputted by the first comparator (COMP1) and the edge detection signal (S4) outputted by the edge detecting circuit (34) to switch, in accordance with the level transitions of these signals, the charging/discharging states of the charging/discharging circuit (32). The voltage of the capacitor (C2) is outputted as a triangular waveform signal (Vosc).