Stmicroelectronics S.r.l.

Francesco DiStefano

Giuseppe Scilla

The trimming circuit includes a plurality of trimmable resistances that may be coupled among them, each resistance being connected in parallel to a respective fuse. The trimming circuit allows burning any number of fuses according to a fixed trimming sequence using only one or two dedicated pins because it includes an input diode-connected transistor and a plurality of trimming transistors of different sectional area, each connected to force current throughout a respective one of the shunt fuses and coupled to the input diode-connected transistor such to mirror the current flowing therethrough. The fuses of the trimming circuit may be burnt by applying a trimming voltage to the diode-connected input transistor with a voltage generator connected between a dedicated pin of the circuit and a terminal at a reference potential, such to force a current therethrough as long as the mirrored currents flowing throughout the fuses burn them.

Electronic trimming circuit

An electronic trimming circuit carries out a trimming operation on portions of an integrated device. The circuit includes N trimmable interconnected resistances, each connected in parallel to a respective shunt fuse. N trimming transistors are each connected to a respective one of the shunt fuses to force therethrough substantially the whole current flowing in the respective trimming transistor. N bias networks are each functionally connected to a control terminal of a respective one of the trimming transistors to directly bias an active junction thereof. An externally driven heating device is thermally coupled with the active junctions of the trimming transistors adapted to raise the temperature thereof.

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Palagonia, Italy

Francesco DiStefano