Patent ID: 7746130
Filing Date: 2010-06-29
Classification: H03F,H03K

Abstract:
1. A triangular wave generating circuit, comprising: an integrating unit including a capacitor, the integrating unit having an output for providing a triangular wave signal; first and second constant current sources for charging and discharging the capacitor; a switch unit for coupling the first and second current sources to the integrating unit to charge and discharge the capacitor in response to an internal clock signal; a high/low level limiter including first and second comparing units for comparing the output of the integrating unit with upper and lower triangular wave peak limit reference voltages, respectively, and providing output signals indicating when the output of the integrating unit coincides with the peak limit reference voltages; a clock generator for providing the internal clock signal in response to the comparing unit output signals; and means for varying a peak-to-peak swing of the triangular wave signal over time to synchronize the internal clock signal with an externally supplied clock pulse.