Infineon Technologies Ag

International Rectifier Corporation

David Jacquinod

Andre Mourrier

Michael Asam

Christian Djelassi-Tscheck

Mario Tripolt

Mirko Bernardoni

Robert Illing

Vincent Thiery

Bernhard Auer

Michael Luschin

Louis Janinet

Thomas Blasius

In accordance with an embodiment, a circuit for driving an electronic switch includes a control circuit configured to trigger a switch-on and a switch-off of the electronic switch in accordance with an input signal, wherein the control circuit is further configured to trigger the switch-off of the electronic switch in response to an under-voltage signal signaling an under-voltage state; and an under-voltage detection circuit configured to signal the under-voltage state when a supply voltage received at a supply node is below an under-voltage threshold value, wherein the under-voltage threshold value depends on a load current passing through the electronic switch.

Smart electronic switch

According to an embodiment, a current monitoring circuit includes a signal shaping unit configured to receive a current sense signal and provide a modified current signal; a filter configured to receive the modified current signal and to provide a respective filtered signal; a comparator configured to receive the filtered signal and a threshold value and to indicate when the filtered signal exceeds the threshold value. The signal shaping unit is configured to calculate a level of the modified current signal from a corresponding level of the current sense signal in accordance with non-linear function.

An integrated circuit that may be employed as a smart switch is described herein. In accordance with one embodiment the integrated circuit includes a power transistor coupled between a supply pin and an output pin and further includes a control circuit configured to trigger a switch-on and a switch-off of the power transistor in accordance with an input signal. The control circuit is configured to trigger a switch-off of the power transistor when a load current passing through the power transistor is at or above a predetermined current and a supply voltage received at the supply pin is at or below a predetermined threshold voltage.

A circuit protective device includes a current sensing circuit adapted to be coupled to an output power switch to provide a feedback signal representative of the output current, an overcurrent sensor responsive to the feedback signal exceeding a presettable reference level to provide an overcurrent alert signal, a function generator responsive to the feedback signal to generate a first signal related to the output current according to a preset functional relationship, an integration circuit coupled to the output of the function generator to provide a second signal representative of the product of the first signal and t, where t is the elapsed time following generation of an overcurrent alert signal, and a control circuit responsive to a presettable value of the second signal to disable a gating circuit for the power switch, the shut-down signal being provided at a time which depends on the magnitude of the overcurrent signal. The control circuit also shuts down the gating circuit if the output current exceeds a second preset limit representing a short circuit condition with substantially no delay. A related method, and a function generator in the form of a piece-wise linear approximation circuit are also disclosed.

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La Fare les Oliviers, France

David Jacquinod