Stmicroelectronics S.r.l.

Stmicroelectronics (grenoble 2) Sas

Francesco Ferrazza

Claudio Adragna

Jean Camiolo

Nathalie Ballot

Mirko Gravati

Domenico Tripodi

Christian Leone Santoro

Davide Lena

Ambrogio Giuseppe D'Adda

Massimiliano Leggenda

In an embodiment, a USB interface includes a transformer, a primary winding of the transformer, and a first switch in series between a first and a second node, a secondary winding of the transformer and a component in series between a third and a fourth node, the fourth node configured to be set a first reference potential, a second switch connected between the third node and a first terminal, the first terminal configured to provide an output voltage of the USB interface; wherein the component is configured to avoid a current circulation in the secondary winding when the first switch is closed and a control circuit configured to compare a first voltage of an interconnection node between the secondary winding and the component to a first threshold and compare the first voltage to a second threshold when the first voltage is, in absolute values, above the first threshold.

USB interface

A control circuit for controlling a switching stage of an electronic converter includes a first terminal configured to provide a drive signal and a second terminal configured to receive a first feedback signal. A third terminal receives a second feedback signal and a driver circuit provides the drive signal as a function of a PWM signal. A PWM signal generator circuit generates the PWM signal as a function of the first feedback signal, a reference threshold and the second feedback signal or a slope compensation signal. The control circuit is configured to sense an input signal, provide a first compensation parameter, and provide a first compensating signal as a function of a power of the input sensing signal.

Control circuit, corresponding electronic converter device and method of operating thereof

In an embodiment, an USB interface includes a transformer, a primary winding of the transformer and a first switch connected in series between a first node and a second node, a secondary winding of the transformer and a component connected in series between a third node and a fourth node, the fourth node configured to be set a first reference potential, a second switch connected between the third node and a first terminal, the first terminal configured to provide an output voltage of the USB interface; wherein the component is configured to avoid a current circulation in the secondary winding when the first switch is closed and a control circuit configured to compare a first voltage of an interconnection node between the secondary winding and the component to a first threshold and compare the first voltage to a second threshold when the first voltage is, in absolute values, above the first threshold.

In an embodiment, a method for operating an ACF converter includes: turning on a low-side transistor that is coupled between a primary winding of a transformer and a reference terminal to cause a forward current to enter the primary winding, turning off the low-side transistor; after turning off the low-side transistor, turning on a high-side transistor that is coupled between the primary winding and a clamp capacitor to cause a reverse current to flow through the primary winding; and after turning on the high-side transistor, when an overcurrent of the reverse current is not detected, keeping the high-side transistor on for a first period of time, and turning off the high-side transistor after the first period of time, and when the overcurrent of the reverse current is detected, turning off the high-side transistor without keeping the high-side transistor on for the first period of time.

Cycle-by-cycle reverse current limiting in ACF converters

A control device for a switching converter having a transformer, with a primary winding receiving an input quantity, a secondary winding providing an output quantity, an auxiliary winding providing a feedback quantity, and a switch element. The control device has a processing module for generating a control signal for switching the switch element on the basis of the feedback quantity in order to regulate the output quantity via alternation of phases of storage and transfer of energy. The processing module controls the end of the transfer phase by comparing the feedback quantity with a comparison threshold. A discrimination circuit generates a signal for discrimination between the presence of a short circuit on the output or the fact that the input quantity is lower than a threshold. The processing module controls the end of the energy-transfer phase also on the basis of the discrimination signal.

Control device for a quasi-resonant switching converter, and corresponding control method

A method of controlling a switching converter and a related controller suitable for the switching converter allow to implement a burst-mode functioning without generating acoustic noise and with a relevantly reduced ripple of the regulated DC voltage or current provided in output to a supplied load. The method includes sensing the difference between the error signal and the burst-stop threshold at the beginning of a burst period. If the error signal has surpassed (either upwards or downwards) the burst-stop threshold, the method sets the switching stage in a high impedance state at a new active edge of a clock signal, keeps the switching stage in the high impedance state for an integer number of cycles of the clock signal, and re-enables the switching stage to switch the energy tank circuit up to the end of the burst period. The integer number is determined based on the difference between the error signal and the burst-stop threshold.

Growing community of inventors

Milan, Italy

Francesco Ferrazza