A graphical method for identifying positive feedback loops automatically in self-biasing circuit for determining the uniqueness of operating points

A graphical method for identifying positive feedback loops in analog circuits is presented for the purpose of identifying the stable equilibrium points. Graphical models for key analog components are developed and hierarchically used to obtain a graphical representation of an analog circuit. From this graphical circuit representation, positive feedback loops are defined. Applications to identifying Trojan operating states and trust in electronic circuits are discussed.