Why the terms 'current mode' and 'voltage mode' neither divide nor qualify circuits

Abstract

It is often stated in papers that there may be a fundamental difference between current-mode and voltage-mode circuits. In this discussion paper, we show that there is no definition that would clearly divide all circuits into current-mode and voltage-mode. Then we provide evidence that a voltage-mode Gm-C filter and its current-mode counterpart have the same performance. The reason why current-mode circuits often perform differently from voltage-mode circuits is that current-mode circuits often use less loop gain and are less complex. Because one can also build voltage-mode circuits in that way, and current-mode circuits with more gain and complexity, the actual difference between current mode and voltage mode comes from the different preferences of the research groups. We conclude that conscious efforts should be made to re-integrate the knowledge produced by the current-mode research groups into main-stream analog IC design.