Patent FR-2961056-A1 (FR)
Title: Electronic device for protecting a component against the electrostatic discharges, comprises a first terminal and a second terminal, and an electronic unit coupled between the two terminals, where the electronic unit comprises two blocks
Inventor: GALY PHILIPPE
IPC: H03K17/56
Filed: 2010-06-03
Abstract: The electronic device comprises a first terminal (BP) and a second terminal (BN), and an electronic unit coupled between the two terminals. The electronic unit comprises two blocks (BLC1, BLC2) comprising a metal oxide semiconductor (MOS) transistor having a first electrode, a second electrode, a grid, and a parasitic bipolar transistor. The first electrode is coupled with the first terminal, and the second electrode is coupled with the second terminal. A current pulse is provided between the two terminals by operating in a hybrid mode and a function of MOS type in a threshold mode. The electronic device comprises a first terminal (BP) and a second terminal (BN), and an electronic unit coupled between the two terminals. The electronic unit comprises two blocks (BLC1, BLC2) comprising a metal oxide semiconductor (MOS) transistor having a first electrode, a second electrode, a grid, and a parasitic bipolar transistor. The first electrode is coupled with the first terminal, and the second electrode is coupled with the second terminal. A current pulse is provided between the two terminals by operating in a hybrid mode and a function of MOS type in a threshold mode and a parasitic bipolar transistor operation. The substrate and gate of the MOS transistor are respectively floating. The substrate and gate of the MOS transistor are connected together, or not directly connected to one of the first and second terminals. The block further comprises a control circuit configured to, in presence of a current pulse between two terminals, apply a first non-zero voltage on the substrate of the MOS transistor and a second voltage lower than the threshold voltage on the gate of the MOS transistor. The circuit control is configured to apply a first voltage less than a limit voltage corresponding to a substrate source of saturation of the parasitic bipolar transistor. The first electrode of the MOS transistor is a drain, and the second electrode is a source. The control circuit includes a first resistive element having a first terminal connected to the source of the MOS transistor and a second terminal connected to the substrate and the gate of the MOS transistor, and a second resistor element connected between the gate and the source of the MOS transistor. The electronic unit further comprises a diode of which the cathode is connected to the first terminal and whose anode is connected to the second terminal, and two cascaded blocks coupled in series between the first terminal and second terminal symmetrically. Each block further comprises an additional element configured to delay the discharge of the gate capacitance of MOS transistor, where the additional element is connected between the substrate and the gate of MOS transistor or between the substrate of the MOS transistor and the resistive element. The electronic unit further comprises a triac coupled between the first terminal and the second terminal, and of which the trigger is coupled to the common connection terminal between the two blocks. The triac has two fingers integrated in two semiconductor boxes, and the two blocks are respectively integrated on and within two semiconductor boxes. A protection is formed against the electrostatic discharge, and the first and second terminals are intended to be connected to a component to be protected. Independent claims are included for: (1) an input/output cell of an integrated circuit; and (2) a method for protecting a component against the electrostatic discharges.