Mode selection circuit for low-cost integrated circuits such as microcontrollers

摘要

In one form, an integrated circuit includes a negative voltage detector circuit and a logic circuit. The negative voltage detector circuit has a power supply input coupled to a power supply voltage terminal, a ground input coupled to a ground voltage terminal, a first input coupled to a first signal terminal, a second input coupled to a second signal terminal, and an output for providing an enable signal when a voltage on the first signal terminal is less than a voltage on the ground voltage terminal by at least a predetermined amount when a signal on said second signal terminal is in a first predetermined logic state. The logic circuit has an input for receiving the enable signal. The logic circuit changes an operation of the integrated circuit in response to an activation of the enable signal.