An original buffer circuit for medium power and medium frequency operation

We present an output stage buffer circuit that can serve as a near optimal impedance converter with no signal distortion or loss, over a wide range of input and output resistances and a relatively large frequency band. The buffer circuit exhibited the following characteristics: a high input impedance; a high current sourcing capability due to a low output resistance; a minimal quiescent current; a good stability; a flat frequency response over a relatively wide range; an improved response with a flexible block design regardless of the power level and of the frequency within the bandwidth of application. As a result, the circuit behaves as a optimal isolation buffer from dc to some high frequency value imposed by the transition frequency of the transistors used and the number of elementary cells in the buffer circuit, thus allowing the design of independent functional stages within the power circuit of the system at hand.