Patent attributes
A sawtooth waveform generator includes an operational amplifier that generates a ramp signal. The ramp signal charges a capacitor connected between the output of the operational amplifier and the inverting input of the operational amplifier. The inverting input is maintained at a substantially constant voltage, which provides a substantially constant charging current through a timing resistor. The connections to the capacitor are switched when the ramp voltage reaches a predetermined level. A control circuit switches the connections to the capacitor in response to a voltage on one terminal of the capacitor to assure that the connections to the capacitor are switched to a configuration to cause the direction of current flow through the capacitor to be reversed as a result of the switching.
