Patent ID: 7667442

Claim:
A constant voltage power supply circuit with excessive current protection, comprising: an input terminal configured to receive an input voltage; an output terminal configured to receive an output voltage and output current; a constant voltage circuit configured to convert the input voltage into a predetermined constant output voltage; a first excessive current protection circuit configured to reduce the output voltage when the output current is greater than a predetermined maximum current value; and a second excessive current protection circuit having a selectable operative mode and a selectable inoperative mode, and wherein said second excessive current protection circuit, when said second excessive current protection circuit is in said selectable operative mode, further reduces the output voltage if the first excessive current protection circuit decreases the output voltage to less than a predetermined voltage value, and wherein said constant voltage power supply circuit is arranged to operate such that said output terminal receives said output voltage and said output current when said second excessive current protection circuit is in said selectable inoperative mode.