Patent attributes
A series regulator with fold-back over current protection has a high ratio current mirror circuit located between a sense transistor and its voltage output terminal. The series regulator receives an input voltage at an input terminal and generates a stable output voltage at an output terminal. A first amplifier receives a reference voltage. An output transistor is connected between the input terminal and the output terminal and has a gate connected to an output of the first amplifier. A current limiting transistor and the current sense transistor are connected to the input terminal, the output terminal of the first amplifier, and the gate of the output transistor. A voltage divider, connected between the output terminal and ground, generates first and second voltage signals. The first voltage signal is provided to a non-inverting input of the first amplifier. A first current source is connected to the voltage divider and receives the second voltage signal. The current mirror circuit is connected to the current sense transistor, the first current source, and the output terminal. The current mirror circuit returns the sense current to the output terminal and controls the drain-source voltage of the sense transistor.
