CMOS current source for shortened square wave waveforms

In many practical cases sinusoidal signals can be replaced with suitable approximations. Well-known alternative is the three level shortened square wave. By introducing more equally spaced levels, higher harmonics can be further reduced. This multilevel signal is easy to generate digitally and enables simple digital processing involving only additions and shifting. An efficient CMOS technology based current source can be designed to work with such waveforms. The current source consists of Beta-multiplier type biasing circuit, switchable current mirrors and H-bridge output stage. In this case the use of H-bridge output permits possibility to avoid the conventional instrumentation amplifier (simple buffer can be used), resulting a reduction of the whole measuring system complexity.