Sgs-thomson Microelectronics S.r.l.

Fabio Marchio'

Marco Morelli

Giorgio Rossi

Francesco Tricoli

Liana Luoni

A circuit controllably and independently recycles the discharge current of a plurality of inductive loads that are connected between first and second power supply terminals. For each of the loads, an active element for driving the inductive load is provided, as well as a regulator for controlling the recycling of the discharge current from the respective load, which is connected to the control terminal of the active element and to a node for connection between the active element and the respective inductive load.

Circuit and method for controlled independent recycle of discharge

A circuit for recirculating the discharge current of an inductive load driven from the high side of the supply at two different recirculation voltages which may be selected for implementing a slow or a fast recirculation of the current advantageously employs a single power element represented by an NPN transistor functionally connected in parallel to the load. During a driving phase of the load a slow recirculation of the discharge current is implemented by delivering to the base of the recirculation NPN transistor a current sufficient to keep it saturated. upon switching off the load, when a fast recirculation of the dischage current through the recirculation NPN transistor is desired, delivery of the saturating current to the base of the recirculation transistor is interrupted and the transistor remains conducting having a diode and a zener diode in opposition thereto connected in series between ground and the base of the recirculation NPN transistor for permitting the recirculation at a voltage substantially equal to the sum of the voltage drop through the first diode, the zener voltage and the base-emitter voltage of the recirculation NPN transistor.

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Gallarate, Italy

Fabio Marchio'