Abstract: A self-disabling and self-recovering converter includes a transformer connected to a power source and has an auxiliary winding for providing a self-supply voltage after start-up, and an integrated circuit having circuitry and a plurality of pins connected thereto. The converter also includes at least one external line and a sensor connected thereto for an electrical or physical quantity to be monitored. The at least one external line is biased through a first pin with the self-supply voltage, and is functionally coupled to a second pin when a threshold is surpassed. A sectionable voltage clamp chain is connected between the auxiliary winding and a voltage reference. A self-recovery circuit having a first input is connected to the auxiliary winding and a second input is connected through the second pin to the at least one external line.

Abstract: The power output of a static DC--DC converter employing a current mode PWM controller is controlled upon the varying of the switching frequency, by detecting the sawtooth signal produced by the local oscillator generating a DC signal with an amplitude inversely proportional to the frequency. The power output is controlled by alternatively clamping the output voltage of the error amplifier of the PWM controller at a voltage proportional to the amplitude of the DC signal, or by offsetting the signal present on the current sensing resistor by a voltage corresponding to the difference between a constant voltage and the DC signal.

Abstract: A circuit for regulating the charging time of the output node of an amplifier at start up. The output node commonly comprises an external soft-start capacitor charged by a current delivered by a pull-up transistor of a push-pull output stage of the amplifier, through a decoupling diode that is functionally connected between the output node of the amplifier and a terminal of the external soft-start capacitor. The present application provides a current mirror feed back circuit capable of mirroring the charge current of the external soft-start capacitor onto the driving node of the pull-up transistor of the output stage of the amplifier. The regulating circuit permits use of an external capacitance of extremely small size. Upon the reaching of a fully charged condition by the external capacitor, the control circuit self-isolates and does not influence in any way the normal operation of the amplifier.