Abstract: A telephone circuit, which may be monolithically integrated, for feeding a subscriber's telephone line which is coupled via the circuit to a supply voltage generator. The circuit supplies the line with an impedance having a first predetermined value up to a given value of the line current, beyond which is supplies the line with an impedance of a second value greater than the first. The circuit is electrically equivalent to a voltage generator, identical to the supply voltage generator, having circuit components solely of the resistive type connected in series therewith.

Abstract: The bias voltage generator is particularly intended for EPROM memory address decoder circuits, and comprises:(a) a stage generating a reference voltage approximately equal to the turn off threshold voltage of a natural transistor, with its sign changed; and(b) a doubler stage driven by the reference voltage and adapted to supply a bias voltage equal to twice the turn off threshold voltage with its sign changed.Preferably, the bias voltage generator furthermore comprises an adjustment stage driven by the output bias voltage to inject an additional current in negative feedback into said doubler stage when the output bias voltage drops, to return it to the desired value.

Abstract: A voltage regulator includes an output power element and protection circuit connected to a control terminal of the power element in such a way as to cause the element to conduct in a direction opposite to that of normal operation, when the transient overvoltages of polarity opposite to that of the generator reach a predetermined value. The energy associated with the transient is thus discharged via the output power device and it is not therefore necessary to use additional power components to carry out this function, leading to reductions in size and production costs.