Abstract: In one embodiment, a circuit is formed to couple a battery to a charging voltage at least a portion of a time when the charging voltage is greater than zero volts and is less than a first voltage value. The circuit is also formed to decouple the battery from the charging voltage approximately when the charging voltage is greater than the first voltage and also approximately when the charging voltage is no greater than zero volts.

Abstract: In one embodiment, a circuit is formed to couple a battery to a charging voltage at least a portion of a time when the charging voltage is greater than zero volts and is less than a first voltage value. The circuit is also formed to decouple the battery from the charging voltage approximately when the charging voltage is greater than the first voltage and also approximately when the charging voltage is no greater than zero volts.

Abstract: An audio amplifier system (10) is formed to include a voltage reference (16). The voltage reference (16) is formed to utilize a filter having a first cut-off frequency when the output (14) of the voltage reference (16) is less than a first value and to use a second cut-off frequency when the output (14) is greater than the first value.

Abstract: An audio amplifier system (10) is formed to include a voltage reference (16). The voltage reference (16) is formed to utilize a filter having a first cut-off frequency when the output (14) of the voltage reference (16) is less than a first value and to use a second cut-off frequency when the output (14) is greater than the first value.

Abstract: A differential amplifier filter with two channels in phase opposition, wherein each channel includes the same network of passive components which includes two impedances coupled in series between a first input terminal of the filter and a corresponding input of the differential amplifier, a feed-forward impedance coupled between a common node of the two series impedances and an output of the same channel of the differential amplifier, and a feedback impedance coupled between a second input of the differential amplifier and an output of the other channel of the differential amplifier.

Abstract: An integrated circuit constituting a current generator formed by CMOS technology comprises a first pair of similar transistors, one of which recopies the current of the other, subject to a proportionality factor; a second pair of similar transistors, one of which recopies the source voltage of the other; a third pair of similar transistors having different threshold voltages in contrast to the other pairs. A resistor is placed in series with one of the transistors of the third pair in order to compensate for the difference between the threshold voltages, an additional transistor being provided for recopying the current in one of the transistors aforementioned. The current thus produced is stable in time as well as independent of temperature and of the circuit supply voltage.