Protection circuit for protecting a switching device with an inductive load

A Packaged Integrated Circuit comprising:

• a switching device including flyback body diodes, the switching device being arranged to control a current through an inductive load subject to a supply voltage, by switching a first and a second terminal of the inductive load to the respective pole of the supply voltage, and the switching device being controlled by a switching control device;
• and
• a protection device for protecting the switching device,
• wherein the protection device includes:
• measuring means for measuring a voltage level on a first terminal of the load;
• decision means for making a decision on switching the first terminal of the load if the measured voltage level exceeds the supply voltage, to counteract the voltage level of the first terminal;
• and
• instructing means for instructing the switching control device based on the decision on switching the first terminal of the load, to limit the current through a body diode by counteracting the voltage level over the load.

An apparatus including at least one motor, and a Packaged Integrated Circuit coupled to the motor, said Packaged Integrated Circuit comprising:

• a switching device including flyback body diodes, the switching device being arranged to control a current through an inductive load subject to a supply voltage, by switching a first and a second terminal of the inductive load to the respective pole of the supply voltage, and the switching device being controlled by a switching control device;
• and
• a protection device for protecting the switching device,
• wherein the protection device includes:
• measuring means for measuring a voltage level on a first terminal of the load;
• decision means for making a decision on switching the first terminal of the load if the measured voltage level exceeds the supply voltage, to counteract the voltage level of the first terminal;
• and
• instructing means for instructing the switching control device based on the decision on switching the first terminal of the load, to limit the current through a body diode by counteracting the voltage level over the load.

A method for protecting a switching device arranged to control a current through an inductive load subject to a supply voltage, by switching a first and a second terminal of the inductive load to the respective pole of the supply voltage, the switching device being controlled by a switching control device, the switching control device operating based on a predetermined algorithm, and the switching device comprising flyback body diodes, said method comprising the steps of:

• measuring a voltage level on a first terminal of the load;
• making a decision on switching the first terminal of the load if the measured voltage level exceeds the supply voltage, to counteract the voltage level of the first terminal;
• and
• instructing the switching control device based on the decision on switching the first terminal of the load, to limit the current through a body diode by counteracting the voltage level over the load.

A device for controlling an inductive load, said device comprising:

• a switching device including a plurality of switches and a plurality of flyback body diodes, the switching device being coupled to first and second terminals of the inductive load for controlling current through the load by opening and closing the switches so as to selectively couple and decouple the terminals of the load with first and second supply voltages;
• a switching control device coupled to the switching device for controlling the opening and closing of the switches of the switching device;
• and
• a protection device coupled to the switching control device for, when the switching control device controls two of the switches of the switching device to be open so that the first terminal of the load is decoupled from both the first and second supply voltages and a voltage level on the first terminal of the load exceeds the first supply voltage, instructing the switching control device to close one of the two switches so as to limit the current through a corresponding one of the body diodes of the switching device.