Stmicroelectronics S.r.l.

Nunzio Greco

Giuseppe Palmisano

Egidio Ragonese

Nunzio Spina

Alessandro Parisi

Ranieri Guerra

Pierpaolo Lombardo

Francesca Giacoma Mignemi

Osvaldo Enrico Zambetti

Leandro Grasso

Serena Angela Versace

In accordance with an embodiment, a method of operating a buck-boost power supply includes operating the buck-boost power supply in a buck mode by providing a PWM signal to a first half-bridge circuit, and turning on a charge transfer switch coupled between a first boosted supply node of a second driver circuit coupled to the first half-bridge circuit and a second boosted supply node of a second driver circuit coupled to a second half-bridge circuit when a voltage between the second boosted supply node and an output of the second half-bridge circuit is below a first threshold; and operating the buck-boost power supply in a boost mode by providing a PWM signal to the second half-bridge circuit, and turning on the charge transfer switch when the voltage between the first boosted supply node and an output of the first half-bridge circuit is below a second threshold.

Buck-boost boot refresher circuit

A buck-boost converter circuit includes a mode selection circuit that asserts a buck enable signal if an input voltage is higher than a lower threshold, and asserts a boost enable signal if the input voltage is lower than an upper threshold. A control circuit asserts a buck PWM signal upon a pulse in a buck clock and de-asserts the buck PWM signal if a buck ramp is higher than a buck control signal, and it keeps the buck PWM signal asserted if the buck enable signal is de-asserted. The control circuit asserts a boost PWM signal upon a pulse in a boost clock and de-asserts the boost PWM signal if a boost ramp is higher than a boost control signal, and it keeps the boost PWM signal de-asserted if the boost enable signal is de-asserted.

Buck-boost DC-DC converter circuit and corresponding method of operation

A DC-DC converter includes: an transformer having a primary winding and a secondary winding magnetically coupled to the primary winding; a power oscillator applying an oscillating signal to the primary to transmit a power signal to the secondary winding; a rectifier connected to the secondary winding of the transformer to obtain an output DC voltage by rectification of the power signal; comparison circuitry to generate an error signal representing a difference between the output DC voltage and a reference voltage; a transmitter connected to the secondary winding of the transformer to apply an amplitude modulation to the power signal at the secondary winding of the transformer in response to the error signal to thereby produce an amplitude modulated signal at the primary winding; and a receiver and control circuit connected to the primary winding to control an amplitude of the oscillating signal as a function of the amplitude modulated signal.

Galvanically isolated DC-DC circuit converter with data communication, corresponding system and corresponding method

A DC-DC converter includes a transformer having primary and secondary windings, a power oscillator applying an oscillating signal to the primary winding to transmit a power signal to the secondary winding, a rectifier obtaining an output DC voltage by rectifying the power signal at the secondary winding, and comparison circuitry generating an error signal representing a difference between the output DC voltage and a reference voltage value. A transmitter connected to the secondary winding performs an amplitude modulation of the power signal at the secondary winding to transmit an amplitude modulated power signal to the primary winding, the amplitude modulation based upon the error signal and modulating a stream of data to the primary winding. A receiver coupled to the primary winding demodulates the amplitude modulated power signal to recover the error signal and the stream of data. An amplitude of the oscillating signal is controlled by the error signal.

An oscillator is coupled to a first side of a galvanic barrier for supplying thereto an electric supply signal. The oscillator is configured to be alternatively turned on and off as a function of a PWM drive signal applied thereto. A receiver circuit coupled to the galvanic barrier receives therefrom a PWM power control signal. A signal reconstruction circuit coupled between the receiver circuit block and the oscillator provides to the oscillator a PWM drive signal reconstructed from the PWM power control signal. The signal reconstruction circuit includes a PLL circuit coupled to the receiver circuit block and configured to lock to the PWM control signal from the receiver circuit block. A PLL loop within the PLL circuit is sensitive to the PWM drive signal applied to the oscillator. The PLL loop is configured to be opened as a result of the power supply oscillator being turned off.

Galvanic isolation circuit and system and a corresponding method of operation

A DC-DC converter includes a power oscillator connected to a first transformer winding, and a channel conveying a data stream through galvanic isolation by power signal modulation. A rectifier rectifies the power signal to produce a DC voltage. A comparator produces an error signal from the DC voltage and a reference voltage. An analog-to-digital converter converts the error signal to a digital power control value. A multiplexer multiplexes the digital power control value with the data stream to obtain a multiplexed bitstream. A transmitter driven by the multiplexed bitstream performs amplitude modulation of the power signal at a second transformer winding. A receiver connected to the first winding demodulates the amplitude modulated power signal. A demultiplexer demultiplexes the data stream and the digital power control value. A digital-to-analog converter converts the digital power control value to an analog control signal for the power oscillator.

Power and data are transmitted via a transformer including primary side and secondary side. A primary side signal is generated by coupling a first oscillator signal modulated with a data signal with a second oscillator signal that is selectively switched on and off. At the secondary side a secondary signal is generated. A demodulator demodulates the secondary signal to recover the data signal. A rectifier processes the secondary signal to recover a power supply signal controlled by switching on and off the second oscillator.

Method of transmitting power and data across a galvanic isolation barrier, corresponding system and apparatus

A galvanic isolation circuit is formed by a differential transformer having primary and secondary windings for transmission of signals over a carrier between the primary and the secondary windings of the transformer. A galvanic isolation oxide layer is provide between the primary and secondary windings. Each winding includes include a center tap providing a low-impedance paths for dc and low frequency components of common-mode currents through the differential transformer. A pass-band stage is coupled to the secondary winding of the transformer and configured to permit propagation of signals over said carrier through the pass-band amplifier stage while providing for a rejection of common-mode noise.

Galvanic isolation circuit, corresponding system and method

A galvanic isolation system includes a first isolation barrier and a second isolation barrier. The first isolation barrier includes a transformer. The second isolation barrier includes an inductive circuit connected to a secondary winding of the transformer. The first and the second isolation barriers are coupled to form an LC resonant network.

Galvanic isolation system, apparatus and method

A galvanic isolation is provided between a first circuit and a second circuit. A first galvanically isolated link is configured to transfer power from a first circuit to a second circuit across the galvanic isolation. A second galvanically isolated link is configured to feed back an error signal from the second circuit to the first circuit across the galvanic isolation for use in regulating the power transfer and further configured to support bidirectional data communication between the first and second circuits across the galvanic isolation.

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Bronte, Italy

Nunzio Greco