Current limiter system, circuit and method for limiting current

An integrated circuit, comprising:

• a determination circuit, generating a short-circuit signal when the current value exceeds a predetermined threshold;
• and
• a current supply circuit coupled to a voltage supply source, the current sensor, and the determination circuit, comprising a current limiting path and a current pass-through path,
• wherein the determination circuit determines whether the short-circuit signal is generated;
• if yes, the current supply circuit delivers a limited current through the current limiting path to the load upon receiving the short-circuit signal, and if not, the current supply circuit passes the current from the voltage supply source through the pass-through path to the load;
• wherein the current supply circuit comprises:
• a current source producing a bias current;
• a first transistor in a diode connection, coupled to the current source;
• a second transistor coupled to the voltage source and the current sensor, connected with the first transistor to form a current mirror and generate a mirrored current, and disconnected from the first transistor to provide the pass-though path;
• a first switch coupled to the determination circuit, the first and the second transistors, receiving the short circuit signal to connect the first and the second transistors;
• and
• a second switch coupled to the determination circuit, a ground and the second transistor, receiving the short-circuit signal to disconnect the second transistor from the ground;
• and
• wherein the limited load current is determined by width to length (W/L) ratio of the first and the second transistors, and the bias current.

A method of limiting a current through a load, comprising the steps of:

• providing a current indication indicating the value of the current through the load;
• generating a short-circuit signal when the current value exceeds a predetermined threshold;
• determining whether the short-circuit signal is generated;
• if yes, delivering a limited current through a current limiting path in a current supply circuit to the load, upon reception of the short-circuit signal;
• and
• if not, passing the current from a voltage source through a pass-though path in the current supply circuit to the load;
• wherein the current supply circuit comprises:
• a current source producing a bias current;
• a first transistor in a diode connection, coupled to the current source;
• a second transistor coupled to the voltage source and the current sensor, connected with the first transistor to form a current mirror and generate a mirrored current, and disconnected from the first transistor to provide the pass-through path;
• a first switch coupled to the determination circuit, the first and the second transistors, receiving the short-circuit signal to connect the first and the second transistors;
• and
• a second switch coupled to the determination circuit, a ground and the second transistor, receiving the short-circuit signal to disconnect the second transistor from the ground;
• and
• wherein the limited load current is determined by width to length (W/L) ratio of the first and the second transistors, and the bias current.