Texas Instruments Corporation

Stmicroelectronics S.r.l.

National Semiconductor Corporation

Analog Devices International Unlimited Company

Texas Instruments Incorporated Deutschland, Gmbh

Giovanni Frattini

Maurizio Granato

Roberto Giampiero Massolini

Giacomo Calabrese

Giulio Ricotti

Shailendra Kumar Baranwal

Luca Fontanella

Pierluigi Albertini

Pietro Giannelli

Michael Lueders

Joyce Marie Mullenix

David I Anderson

Christian Rott

Bruno Murari

Anindya Poddar

Andrea Baschirotto

Jeffrey Anthony Morroni

Gianpaolo Lisi

Sandro Rossi

Ali Djabbari

Gerard G Socci

Paolo Mattavelli

Caterina Riva

Giorgio Pedrazzini

Vijaylaxmi Gumaste Khanolkar

Guido Gabriele Albasini

Kosha Mahmodieh

Giorgio Spiazzi

Evan Reutzel

Enrico Temporiti Milani

Randall Walberg

Keith W Bennett

Filip Savic

Raj Subramoniam

Disclosed herein is a symmetric split planar transformer in the context of a DC-DC isolated converter. The symmetric split planar transformer reduces or eliminates asymmetry in the distribution of parasitic capacitance across the isolation barrier going from one end to another end of a primary coil, and as a result, undesirable electromagnetic interference (EMI) due to common mode dipole emission across the isolation barrier may be reduced. In some embodiments, the primary winding is split into at least a first coil and a second coil, each occupying a different area side-by-side on a substrate. The transformer is symmetric in the sense that a capacitive coupling of the first coil to a secondary winding is the same as a capacitive coupling of the second coil to the secondary winding, such that common mode EMI may be reduced. Each coil may include stacked spiral coil portions in multiple metal planes to increase inductive density across the isolation barrier. Furthermore, in some embodiments the first and second coils may have opposite spiral directions such that far field radiation effect from the transformer may be reduced.

Symmetric split planar transformer

In described examples, an isolated DC-DC converter includes: an input node for receiving an input voltage; a transformer including a primary side having first and second terminals and a primary side ground; and first and second low-side switches. The first low-side switch is coupled between the first terminal and the primary side ground. The second low-side switch is coupled between the second terminal and the primary side ground. A first voltage is across the first low-side switch, and a second voltage is across the second low-side switch. Also, the isolated DC-DC converter includes first and second high-side switches. The first high-side switch is coupled between the first terminal and the input node. The second high-side switch is coupled between the second terminal and the input node. Further, the isolated DC-DC converter includes a switch controller.

Isolated DC-DC converter

A converter circuit includes a primary side having a resonator and a first control circuit configured to control the resonator. The converter circuit also includes a secondary side having a resonant rectifier and a second control circuit configured to control the resonant rectifier. The converter circuit further includes a transformer configured to electrically isolate the primary side from the secondary side. The second control circuit is configured to turn the resonant rectifier on and off. The first control circuit may be configured to detect when the resonant rectifier is off and, in response, turn the resonator off without using a feedback signal from the secondary side. The first control circuit may be configured to detect when the resonant rectifier is off by detecting when input power to the primary side decreases. The resonant rectifier could be turned on and off by detuning the resonant rectifier.

Resonant isolated converters for power supply charge balancing systems and other systems

Disclosed examples include isolated load switch driver circuits to drive a load, including an impedance circuit that receives a digital input voltage signal from a signal source, and selectively allows a current signal to flow from the signal source to charge a buffer capacitor. An impedance control circuit controls the impedance circuit to limit the current signal in response to the buffer capacitor reaching a first threshold voltage, and an output circuit provides an output isolated from the digital input voltage signal to switch the load. A signaling circuit selectively enables the output circuit to draw power from the buffer capacitor in response to the voltage of the buffer capacitor reaching the first threshold voltage.

Current limiting I/O interface and isolated load switch driver IC

Disclosed examples include isolated dual active bridge (DAB) DC to DC converters with first and second bridge circuits, a transformer with a sense coil, and a secondary side control circuit to provide secondary side switching control signals to regulate an output voltage or current signal by controlling a phase shift angle between switching transitions of the secondary side switching control signals and switching transitions of a secondary side clock signal, where the secondary side control circuit includes a clock recovery circuit to synchronize the secondary side clock signal to transitions in a sense coil voltage signal of the sense coil.

Isolated phase shifted DC to DC converter with secondary side regulation and sense coil to reconstruct primary phase

In described examples, an isolated DC-DC converter includes: an input node for receiving an input voltage; a transformer including first and second terminals; first and second low-side switches; and first and second high-side switches. The first low-side switch is coupled between the first terminal and a primary side ground. The second low-side switch is coupled between the second terminal and the primary side ground. The first high-side switch is coupled between the first terminal and the input node and is configured to be activated by a voltage at the second terminal. The second high-side switch is coupled between the second terminal and the input node and is configured to be activated by a voltage at the first terminal. Further, the isolated DC-DC converter includes a switch controller to cause the first and second voltages to alternatingly be zero by opening and closing the first and second low-side switches.

A switched voltage converter may be controlled with load current feedforward control loop in addition to an output voltage feedback loop. The converter includes a first switch device that is controlled to open and close at a selected switching rate with a selected duty cycle. The first switch device is coupled in series with an inductor and conducts current through the inductor while the first switch is closed. A second switch device conducts current from the inductor to an output capacitor and to load while the first switch is open to produce an output voltage and a resulting load current through the load. The load current is measured in a continuous manner and a load current feedforward control signal is generated that is representative of the load current. The switch rate and/or duty cycle of the first switch is adjusted in response to the load current feedforward control signal.

Switched converter control using adaptive load current sensing and feedforward technique

Described examples include DC to DC converters and systems with switching circuitry formed by four series-connected switches, inductors connected between the ends of the switching circuitry and corresponding output nodes, and with a flying capacitor coupled across interior switches of the switching circuitry and a second capacitor coupled across the ends of the switching circuitry. A control circuit operates the switching circuit to control a voltage signal across the output nodes using a first clock signal and a phase shifted second clock signal to reduce output ripple current and enhance converter efficiency using valley current control. The output inductors are wound on a common core in certain examples.

Multilevel boost DC to DC converter circuit

A transducer has an input and produces a mechanical output, wherein the magnitude of the mechanical output of the transducer is dependent on the frequency and magnitude of current at the input. A driver for the transducer includes a device having a transfer function associated with the device, the device having a device input and a device output, the device output being connectable to the input of the transducer and the device input being connectable to a power source. The device attenuates the current output at a frequency that causes a peak in the magnitude of the mechanical output of the transducer.

Transducer driver attenuating input current frequency at maximum mechanical output

Disclosed examples include isolated phase shifted dual active bridge DC to DC converters with a first bridge circuit operative according to a primary side clock signal to provide a primary voltage signal to a transformer primary winding, a second bridge circuit operative according to a secondary side clock signal to convert a secondary voltage signal from a transformer secondary winding to provide an output voltage signal, and a secondary side control circuit that alternately operates in a first mode to regulate the output voltage signal by controlling a phase shift angle between switching transitions of secondary side switching control signals and switching transitions of the secondary side clock signal, and a second mode to discontinue the secondary side switching control signals and synchronize the secondary side clock signal to transitions in the secondary voltage signal while the secondary side switching control signals are discontinued.

Isolated phase shifted DC to DC converter with frequency synthesizer to reconstruct primary clock

An electronic device, which includes an H-bridge circuit and a miniaturized transformer that is coupled to operate at VHF frequency, and a driver circuit for an n-type power transistor of the H-bridge circuit are disclosed. The driver circuit includes a first p-type transistor and an n-type transistor coupled between an upper rail and a lower rail, with an output taken between the drains of the first p-type transistor and the n-type transistor being coupled to a gate of the n-type power transistor. The driver circuit also includes a sample-and-hold capacitor coupled to capture a drain voltage for the first n-type power transistor on a first edge of a control signal for the first n-type power transistor and a comparator coupled to compare the captured drain voltage to a lower rail on a given edge of a clock signal and to provide a comparator value. The driver circuit also includes an up/down counter, which is coupled to receive the comparator value, to adjust a counter value responsive to receiving the comparator value and to output the counter value, and a first timing circuit that is coupled to receive the counter value and to send an adjustable pulse towards a gate of the first p-type transistor and a gate of the n-type transistor.

Isolated high frequency DC/DC switching regulator

Growing community of inventors

Travaco' Siccomario, Italy

Giovanni Frattini