Patent ID: 7663858

Claim:
Control device for an electro-actuator comprising a first and a second input terminal which are connected, in use, to an electrical energy source; a first and a second output terminal which are connected, in use, to the electro-actuator; and selectively controlled switch means which is activated in order to connect the first and second output terminals to the first and second input terminals in predetermined operative conditions; controlled switch means comprising first controlled switch means which are connected between the first input terminal and the first output terminal and second controlled switch means which are connected between the second input terminal and the second output terminal; the control device comprises: first detector means which are connected to the ends of the first controlled switch means and provide a first signal (V HS ) of the current flowing in the first controlled switch means, wherein the first detector means comprises: first threshold comparator means which are configured to compare a value correlated to the current flowing in the first controlled switch means with a first threshold value (V TH — HS ) of a predetermined upper limit for the current flowing in the first controlled switch means and generates the first signal (V HS ); the first signal (V HS ) indicating whether the current flowing in the first controlled switch means has exceeded the upper limit or not, the predetermined upper limit comprising the maximum current flowing (I D — MAX ) in the first controlled switching means under normal operating conditions, the control device further comprising a threshold generator element which supplies the first threshold value with a value such as to cause a complete shutdown of the current when current flowing is outside a normal operating condition; wherein the maximum current flowing in the first controlled switching means under normal operating conditions is a function of the current I D which passes through the first controlled switching means, when turned on, giving rise to a voltage drop V DS equal to R DS — ON ·I D with R DS — ON having known values for the first controlled switching means and a known maximum current I D — MAX , wherein V DS — MAX =R DS — ON — MAX ·I D — MAX , with detection of any short circuit when the value of the threshold voltage V TH — HS exceeds V DS — MAX , through the first controlled switching means, wherein R DS — ON — MAX is the channel resistance at the maximum junction temperature, having a predetermined known value for the first controlled switch, without functioning problems at low temperatures, with the device being configured such that passing current therethrough on short circuit gives rise to a sudden increase in junction temperature.