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A circuit for the generation of an electrical signal of constant duration comprises a capacitor, a constant current generator for charging the capacitor, and a voltage comparator to compare the voltage present at the terminals of the capacitor with a reference voltage. The voltage comparator supplie

A circuit for the generation of an electrical signal of constant duration comprises a capacitor, a constant current generator for charging the capacitor, and a voltage comparator to compare the voltage present at the terminals of the capacitor with a reference voltage. The voltage comparator supplies at an output a digital signal dependent upon the voltage across the capacitor. The constant current generator comprises a transistor biased with a voltage between gate and source obtained as the difference between the sum of two gate-source voltages of two transistors and a gate-source voltage of another transistor.

대표청구항 ▼

[ I claim:] [1.] Circuit for the generation of an electrical signal of constant duration and independent of temperature and process variables, comprising:a capacitor;a constant current generator for charging the capacitor;a voltage comparator to compare the voltage present across the capacitor with

[ I claim:] [1.] Circuit for the generation of an electrical signal of constant duration and independent of temperature and process variables, comprising:a capacitor;a constant current generator for charging the capacitor;a voltage comparator to compare the voltage present across the capacitor with a first reference voltage and supply at output a digital signal dependent upon the voltage across the capacitor; andsaid constant current generator comprising a first MOS transistor having a gate terminal, a source terminal and a drain terminal, biased with a fixed voltage between gate and source to conduct a certain current between the drain and source terminals, said fixed voltage being obtained as the difference between the sum of two gate-source voltages of a second and a third MOS transistors and a gate-source voltage of a fourth MOS transistor, wherein said second and third transistors are connected in diode configuration with each having its gate terminal joined to its drain terminal and are connected together in series between a first current generator and a second reference voltage.