Sgs-thomson Microelectronics S.r.l.

Stmicroelectronics S.r.l.

Paolo Cordini

Domenico Rossi

Giorgio Pedrazzini

Paola Galbiati

Massimo Pozzoni

Michele Palmieri

Luca Bertolini

Giuseppe Scrocchi

In a junction isolated integrated circuit including power DMOS transistors formed in respective well regions or in an isolated epitaxial region on a substrate of opposite type of conductivity, circuits are formed in a distinct isolated region sensitive to oversupply and/or belowground effects. These effects are caused by respective power DMOS transistors coupled to the supply rail or ground. These effects are alternatively controllable by specifically shaped layout arrangements, and may be effectively protected from both effects. This is achieved by interposing between the region of sensitive circuits and the region containing the power DMOS transistors for which the alternatively implementable circuital arrangements are not formed, the region containing the power DMOS transistors coupled to the supply rail or to a ground rail for which the alternatively implementable arrangements are formed. The special interposition separates and shields the sensitive circuits from the power device whose oversupply or belowground effect is not countered by specific circuit arrangements.

Belowground and oversupply protection of junction isolated integrated circuits

A fully digital, current mode, PWM control is realized by employing two distinct comparators, both reading the voltage drop on a sensing resistance. The first comparator exerts an open-loop current mode control. The second comparator, establishing a second higher current threshold than the current threshold set by the first comparator, triggers a disabling circuit of the output power transistor for a preset period of time, when the current level through the output stage uncontrollably rises beyond the second threshold. This may occur because of an insufficient discharge from the load circuit inductance during off-phases of the output power transistor of the extra energy stored during switching delay periods of the first (open loop control) comparator. The frequency of the sequence of bursts may be precisely controlled to be well outside the frequency range of interest to prevent disturbances.

Dual threshold current mode digital PWM controller

The present invention relates to an integrated input/output interface for low and/or high voltage range signals of the digital and/or analog type. It comprises essentially a power amplification circuit block (2) having at least one low voltage range input terminal (A) and at least one high voltage range output terminal (B), and a second amplification circuit block (3) having a high voltage range input terminal connected to said high voltage range output terminal (B) and at least one low voltage range output terminal (D). A conventional circuit block (4) prevents a high voltage range signal being input to said high voltage range terminal (B) from propagating through the first power amplification circuit block (2), so that it only affects the second amplification circuit block (3). This interface is implemented in mixed high voltage bipolar/CMOS/DMOS technology.

Input/output interface circuit for digital and/or analog signals

A stage of both input and output configurable for operation with low and high voltages, comprises:

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Pavia, Italy

Paolo Cordini