Abstract:
An amplifying circuit receiving an input voltage and a reference voltage equal to a fraction of the circuit supply voltage, the reference voltage provided by a time constant circuit, including a circuit for, upon power-on, inhibiting the amplifying circuit for as long as the difference between the value of the provided reference voltage and the voltage at the output of the time constant circuit is greater than a determined threshold.
Abstract:
A pair of complementary current sources includes a reference current source, and two complementary current mirrors having the same number of branches provided with bipolar mirror transistors. The bases of the mirror transistors of the complementary mirrors are connected to a common node. One of the complementary mirrors is connected to the reference source. An intermediate current mirror includes a first slave branch connected to the other complementary current mirror, a second slave branch connected to the reference source, and a master branch connected to the output of a trimming circuit for trimming the complementary currents for substantially equalizing the base currents of the mirror transistors of the complementary current mirrors. The input of the trimming circuit is connected to the common node.
Abstract:
An amplifier including first, second, and third series-connected stages, the third stage including a MOS output transistor having its source or drain forming an output terminal of the amplifier, including means for detecting the transition from a first operating state of the output transistor in which the drain current varies little with the voltage between the drain and the source to a second state in which the drain current varies substantially proportionally to the voltage between the drain and the source; and means for, upon detection of such a transition, having the voltage gain of the amplifier and/or the product between the bandwidth of the amplifier and the voltage gain of the amplifier at the upper limit frequency of the bandwidth drop.
Abstract:
An amplifier includes an input stage with one or more input terminals for receiving a signal to be amplified, and an output terminal. An inverting gain stage includes an input terminal connected to the output terminal of the input stage, an output terminal for delivering an amplified signal, and a variable feedback resistor connected between the output terminal and input terminal thereof. The input stage is a transconductor stage biased by a current source. A transconductance thereof is set by a resistor of the current source so that the amplifier has a gain proportional to the product of the variable feedback resistor multiplied by the transconductance.