Abstract: A current reference circuit for low supply voltages is provided. The current reference circuit includes a series including a resistor and a diode, a current source having one terminal coupled to a supply voltage and another terminal coupled to the series, an operational amplifier having its negative electrode connected to a band gap reference voltage, and a transistor. The diode has its cathode electrode coupled to ground and its anode electrode coupled to the resistor. The transistor has its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source. Also provided are an integrated circuit that includes at least one current reference circuit for low supply voltages and a signal processing system that includes at least one current reference circuit for low supply voltages.

Abstract: A current generator with thermal protection has an input terminal and an output terminal. The current generator includes a voltage generator, first and second controlled switches, a temperature sensor, and a control circuit. The first controlled switch has a control terminal applied to the voltage generator, a first terminal connected to the input terminal, and a second terminal connected to a resistance. The second controlled switch has a control terminal coupled to the voltage generator, a first terminal connected to the resistance, and a second terminal connected to the output terminal. The temperature sensor of the current generator measures the temperature of the generator, and the control circuit controls the second controlled switch so as to open the second controlled switch when the temperature of the current generator overcomes a preset temperature.

Abstract: An active pull-up circuit for connection to an input pin that receives high and low logic level signals and a high voltage signal whose level is higher than the high logic level. The active pull-up circuit includes a pull-up circuit that is coupled between the input pin and a voltage supply line, and a breaking circuit that is coupled between the pull-up circuit and the voltage supply line. The pull-up circuit selectively brings the input pin to the level of the voltage supply line, and the breaking circuit operates to inhibit the pull-up circuit when the high voltage signal is on the input pin. In a preferred embodiment, the breaking circuit inhibits the pull-up circuit by electrically isolating the pull-up circuit from the voltage supply line. A method for selectively pulling-up an input node is also provided.