Patent ID: 7154310
Filing Date: 2006-12-26
Classification: H03K

Abstract:
1. A trapezoid signal generating circuit comprising: a capacitor for producing and outputting a trapezoid signal generating circuit trapezoid signal; a first current output circuit connected to the capacitor for supplying to the capacitor a charging current having a first magnitude; a second current output circuit connected to the capacitor for supplying from the capacitor a discharging current having a second magnitude which is K times (K>1) the charging current when a waveform control signal applied to the second current output circuit is at a first level, and stopping the discharging current when the waveform control signal is at a second level; and a current control circuit for receiving a trapezoid signal generating circuit input signal and being connected to the first current output circuit and the second current output circuit for supplying the first current output circuit with a command signal based on the input signal so that the charging current continuously increases from a first time point when the waveform control signal changes from the first level to the second level and continuously decreases after the trapezoid signal produced and output by the capacitor reaches a predetermined reference level, and for supplying the first and the second current output circuits with the command signal so that both of the charging current and the discharging current continuously increase from a second time point when the waveform control signal changes from the second level to the first level and continuously decrease after the trapezoid signal reaches the predetermined reference level.