Reset device for microprocessor, particularly for automotive applications
AssigneeSGS-Thomson Microelectronics S.A.
InventorVanni Poletto
Life of this patent
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Abstract
A microprocessor reset device comprising a first comparator which, when the input signal of the device falls below a first threshold, closes a switch controlling discharging of a condenser. A second comparator connected to the condenser enables the reset signal when its input signal, correlated with the voltage of the condenser, falls below a seond threshold. For enabling of the reset signal to be dependent on both the duration of the reduction in the input signal below the first threshold, as measured by the voltage present at the terminals of the condenser, as well as on the amount of reduction, the input signal of the second comparator consists of a linear combination of the input signal and the voltage of the condenser, effected by an adding element.
Claims10
A reset device for a microprocessor, particularly for automotive applications, defining an input terminal and an output terminal, and comprising a first comparing stage having first and second inputs connected, respectively, to said input terminal and to a first source of a first threshold signal;
- a switch controlled by said first comparing stage, for switching between a closed and an open state;
- a capacitive element coupled to said switch and being charged and discharged depending on the state of said switch;
- and a second comparing stage having first input-connected to a second source of a second threshold signal, for generating a reset signal having two different logic states and supplied to said output terminal;
- characterised by an adding element having first and second inputs connected, respectively, to said input terminal and to said capacitive element, and including an output connected to a second input of said second comparing stage.
Dependencies are inferred from the claim text.