Figure 1 The usual topology for converting digital square waves to analog sawtooth requires a negative rail. Figure 2 shows an alternative sawtooth topology that employs flying capacitor C2 to reset ...

Figure 1 Buffered triangles, sawtooth waves, and square waves from two op amps. Amplifier A2 integrates the difference between A1’s rail-to-rail output and waveshape control R2 to produce triangle ...