Stmicroelectronics S.r.l.

Stefano Ramorini

Alessandro Gasparini

Alberto Cattani

Germano Nicollini

Alessandro Bertolini

Roberto Pio Baorda

Paolo Angelini

Giorgio Massimiliano Membretti

Giuseppe Calderoni

Andrea Donadel

Eugenio Miluzzi

Marco Attanasio

Federica Papotti

Tommaso Rosa

Massimiliano Giorgio Membretti

A multiphase DC-DC converter has two converter arrangements, each with a switching stage that has a switching node, an inductor, a converter output node, a high-side switch, and a low-side switch. Current sensing circuits detect the instantaneous current flowing through either the high-side or low-side switches, and signal time-averaging circuits produce time-averaged signals indicating the average current during a switch conduction interval. The time-averaged signals are added up and re-scaled based on the time period of the switching nodes' electrical coupling to the converter output nodes to generate an output signal for the average output current.

Multiphase DC-DC switching converter circuit, corresponding power management integrated circuit and display device

A DC-DC boost converter includes an input receiving an input voltage and an output producing an output voltage. A switching stage is formed by a low-side transistor arranged between a switching node and a ground node, and a high-side transistor arranged between the switching node and the output. The high-side transistor includes a body diode having an anode coupled to the switching node and a cathode coupled to the output. The converter is controlled in an asynchronous operation mode where the low-side transistor is driven alternately to a conductive state and a non-conductive state, and the high-side transistor is driven steadily to a non-conductive state. A variable load circuit is selectively coupled between the two output terminals when the converter is in the asynchronous operation mode in order to sink a load current having a value that is a function of a value of the input voltage.

DC-DC converter circuit, corresponding method of operation and method of trimming a DC-DC converter circuit

A switching DC-DC converter circuit includes a switching stage having an input node receiving an input voltage and an output node producing an output voltage. The converter includes feedback loop circuitry coupled to the output node of the switching stage to produce, at a respective output node, a control signal of the converter circuit as a function of a difference between the output voltage and a reference voltage. The converter includes test loop circuitry arranged between an output node of the feedback loop circuitry and the output node of the switching stage. The test loop, when enabled, sources a current to the output node of the switching stage or sinks a current from the output node of the switching stage as a function of a value of the control signal of the converter circuit. The feedback loop circuitry is calibrated during a test phase of the switching DC-DC converter circuit.

DC-DC converter circuit and corresponding method of testing a DC-DC converter circuit

A power switch current sensing circuit includes matching first and second transistors having sources connected to first and second terminals, respectively, of the power switch. A current mirror has a first node coupled to a drain of the first transistor and a second node coupled to a drain of the second transistor. The current mirror sinks a current from the first node equal to a current flowing through the second transistor. A biasing circuit provides a same biasing voltage to the control terminals of the first and second transistors. An output resistance is coupled between the first node and a reference voltage node. A difference between a current flowing through the first transistor and the current sunk by the current mirror circuit from the first node flows through the output resistance. An output voltage produced at the first node is indicative of the current flowing through the power switch.

Current sensing circuit and corresponding DC-DC converter

A half bridge converter is controlled by a circuit including a differential circuit receiving a reference signal and a feedback signal which is a function of an output signal from the converter. The half bridge includes hand and low side switches. A comparator generates a PWM signal for controlling the converter as a function of the duty cycle of the PWM signal in response to a signal at an intermediate node between the hand and low side switches and an output of the differential circuit. A gain circuit block coupled between the intermediate node and the input of the comparator applies a ramp signal to the input of the comparator which is a function of the signal at the intermediate node. A variable gain is applied by the gain circuit block in order to keep a constant value for the duty cycle of said PWM signal irrespective of converter operation.

Circuit for controlling converters, corresponding converter device and method

A converter system includes a reference buffer buffering a reference input to produce a DAC reference, operating from a reference feedback voltage generated by a reference divider. A tail buffer generates a tail voltage from an input voltage generated from the DAC reference by a tail divider. An R-2R type DAC utilizes an R-2R ladder to generate a DAC output from a code. This ladder has a tail resistor coupled to the tail voltage. A feedback buffer buffers the DAC output to produce a converter reference. A DC-DC converter generates a DC output from a DC input, based upon a converter feedback voltage. A feedback divider coupled between the DC output and the converter reference generates the converter feedback voltage. Control circuitry selectively taps the reference divider to produce the reference feedback voltage (performing gain trimming) and selectively taps the tail divider to produce the input voltage (performing offset trimming).

Trimming procedure and code reuse for highly precise DC-DC converters

A control circuit operates to control a switching stage of an electronic converter. The control circuit includes: first terminals providing drive signals to electronic switches of the switching stage; a second terminal receiving from a feedback circuit a first feedback signal proportional to a converter output voltage; and a third terminal configured to receive from a current sensor a second feedback signal proportional to an inductor current. A driver circuit provides the drive signals as a function of a PWM signal generated by a generator circuit as a function of the first and second feedback signals, a reference voltage and a slope compensation signal. A mode selection signal is generated as a function of a comparison between the input voltage and the output voltage. A feed-forward compensation circuit is configured to source and/or sink a compensation current as a function of a variation in the mode selection signal.

Control circuit for controlling a switching stage of an electronic converter, corresponding electronic converter device and method

In an embodiment, a method includes: providing a voltage setpoint to a voltage converter; generating an output voltage at a voltage rail with the voltage converter based on the voltage setpoint; when the voltage setpoint is transitioning from a first voltage setpoint to a second voltage setpoint that has a lower magnitude than the first voltage setpoint, providing a first constant current to a first node coupled to a control terminal of an output transistor to turn on the output transistor, where the output transistor includes a source terminal coupled to a first terminal of a first resistor, and where a current path of the output transistor is coupled to the voltage rail; and turning off the output transistor after the output voltage reaches the target output voltage corresponding to the second voltage setpoint.

Discharge circuit and method for voltage transition management

A first node of converter circuit receives an input, provides an output at a second node, and has a third node coupled by an inductance to ground. A first switch has a current path between the first and third nodes and a second switch has a current path between the third and second nodes. The converter circuit operates in a first state (with the first switch conductive and the second switch non-conductive) and a second state (with the first switch non-conductive and the second switch conductive). Current flowing through the first switch is sensed during the first state to produce a sensing signal indicative of inductance current. The sensing signal is averaged to produce an averaged sensing signal indicative of an average value of the current. The averaged sensing signal is then weighted by a time during which the second switch is conductive to produce a weighted signal.

Method of operating a converter circuit, corresponding converter circuit and driver device

A sensor circuit for a power FET monitors current flowing through the FET and includes a regulator circuit regulating a first current flowing through a sense resistance, so voltage drop at the sense resistance corresponds to voltage drop between terminals of the FET. A measurement circuit provides a second current corresponding (or being proportional) to the first current. A first switch selectively applies the second current to a resistor based on a first control signal, and a low pass filter generates a low-pass filtered signal by filtering voltage at the resistor. A voltage follower generates a replica of the low-pass filtered signal, and a second switch selectively applies the replica to the resistor. When the FET is closed, a control circuit closes the first switch and opens the second electronic switch. When the FET is opened, the control circuit opens the first electronic switch and closes the second electronic switch.

Control circuit for an electronic converter, related integrated circuit, electronic converter and method of operating an electronic converter

Charge pump stages are coupled between flying capacitor pairs and arranged in a cascaded between a bottom voltage line and an output voltage line. Gain stages apply pump phase signals having a certain amplitude to the charge pump stages via the flying capacitors. A feedback signal path from the output voltage line to the bottom voltage line applies a feedback control signal to the bottom voltage line. Power supply for the gain stages is provided by a voltage of the feedback control signal in order to control the amplitude of the pump phase signals. An asynchronous logic circuit generates the switching drive signals for the gain stages with a certain switching frequency which is a function of a logic supply voltage derived from the voltage of the feedback control signal.

Charge pump circuit, corresponding device and method

A converter circuit includes first and second electronic switches coupled at an intermediate node, with an inductor coupled between the intermediate node and an output node. Switching drive control circuitry causes the first and the second electronic switch to switch between a conductive state and a non-conductive state. The drive control circuitry includes a first feedback signal path to control switching of the first and the second electronic switch as a function of the difference between a feedback signal indicative of the signal at the output node and a reference value. A second feedback signal path includes a low-pass filter coupled to the output node and configured to provide a low-pass filtered feedback signal resulting from low-pass filtering of the output signal. The second feedback signal path compensates the feedback signal as a function of the difference between the low-pass filtered feedback signal and a respective reference value.

Converter circuit, corresponding device and method

A bandgap circuit includes a supply node as well as a first and second bipolar transistors having jointly coupled base terminal at a bandgap node providing a bandgap voltage. First and second current generators are coupled to the supply node and supply mirrored first and second currents, respectively, to first and second circuit nodes. A third circuit node is coupled to the first bipolar transistor via a first resistor and coupled to ground via a second resistor, respectively. The third circuit node is also coupled to the second bipolar transistor so that the second resistor is traversed by a current which is the sum of the currents through the bipolar transistors. A decoupling stage intermediate the current generators and the bipolar transistors includes first and second cascode decoupling transistors having jointly coupled control terminals receiving a bias voltage sensitive to the bandgap voltage.

Bandgap reference circuit, corresponding device and method

A sensor comprises a first transistor comprising a first control terminal, a second transistor that is a scaled version of and connected to the first transistor and comprising a second control terminal, an operational amplifier connected to both the first and second transistors and configured to generate an intermediate signal at an output terminal, a variable current source, a current mirror, a measurement circuit, and a chopper circuit. The first and second control terminals are configured to receive a drive signal. The variable current source is configured to generate a first variable current as a function of the intermediate signal. The current mirror configured to apply a second variable current proportional to the first variable current to the second transistor. The measurement circuit is configured to generate a measurement signal indicative of current through the first transistor. The chopper circuit is configured to shift an offset of the operation amplifier.

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Arluno, Italy

Stefano Ramorini