Apple Inc.

Texas Instruments Corporation

Nicola Rasera

Michael Couleur

Michael Lueders

Erich Bayer

Fabio Ongaro

Ivan Shumkov

Siarhei Meliukh

Gaetano Maria Walter Petrina

Joerg Kirchner

Bogdan-Eugen Matei

Ruediger Ganz

Nikola Jovanovic

Cristian Grecu

Ming Sun

Martin Priess

Xiaofeng Wang

Stefan Reithmaier

Roland Bucksch

Johan L Piper

Andrea Acquas

Christian Rott

Florian Neveu

Denis M Darmon

Pietro Gabriele Gambetta

Robert D Zucker

A piecewise linear current-mode digital-to-analog converter circuit approximates an exponential output current over a range of input codes by generating linearly varying currents with different slopes of different ranges of the input codes. The piecewise linear current-mode digital-to-analog converter circuit includes a current generator circuit that generates the output current based on a reference voltage and a feedback signal. A variable resistance circuit is used to generate the feedback signal using the output current. Respective values of the reference voltage and the variable resistance circuit vary as a function of the input code.

Piecewise linear digital-to-analog converter circuit

A high current, low dropout driver circuit is disclosed. The circuit includes a decoder configured to decode a plurality of control bits to generate a plurality of control signals, and a current source having a plurality of devices. The current source is configured to activate at least a subset of the plurality of devices using the control signals to provide a load current to a load circuit, such as a light-emitting diode (LED), using activated ones of the plurality of devices and a control voltage. A control circuit is configured to generate the control voltage based on the load current and a reference current.

High current, low dropout driver circuit

Systems and methods for electronic displays to use reference voltages to control driving current of illuminators are provided. The reference voltages are used to reduce or eliminate cross talk in driving voltages among different illuminators and driving voltage variations from frame to frame. The transient performance of the driving current of the illuminator (e.g., the current rise/decline time, current overshoot issue, current settling time) may be improved by implementing the reference voltages.

Method and apparatus for LED driver to reduce cross talk or flicker

Methods, apparatus, systems, and articles of manufacture are disclosed for cross-conduction detection. An example apparatus includes a cross detector circuit including a first transistor and a second transistor, the first transistor coupled to a load, a third transistor coupled to a first controlled delay circuit and the first transistor, a fourth transistor coupled to a second controlled delay circuit and to the third transistor at a phase node, and a control circuit coupled to the first controlled delay circuit, the second controlled delay circuit, and the load.

Methods and apparatus for cross-conduction detection

A multi-level power converter circuit for computer systems maintains phase alignment with other power converter circuits by employing low-gain phase-locked loop circuits. In order to account for different voltage levels on its terminal nodes, the power converter circuit may perform a comparison of the respective voltage levels of its terminal nodes. Using results of the comparison, the power converter circuit can select different regulation modes using different ones of the low-gain phase-locked loop circuits.

Multi-level power converter with low-gain phase-locked loop control

A hysteretic current control switching power converter with a clock-controlled switching frequency is disclosed. A power converter includes a switching circuit including a high side switch and a low side switch coupled to one another at a switching node, with an inductor being coupled between the switching node and a regulated supply voltage node. The power converter further includes a control circuit configured to alternately cause activation of the high side switch and the low side switch, wherein the control circuit is configured to activate the low side switch in response to a first voltage reaching peak threshold value, the first voltage corresponding to a current through the inductor. A ramp voltage circuit is configured to, in response to a clock signal, generate a ramp voltage, wherein the peak threshold value is based on the ramp voltage.

Hysteretic current control switching power converter with clock-controlled switching frequency

A control system with a voltage-to-time converter for combined buck-boost converter using a single inductor. The system includes a voltage-to-time converter circuit having first and second inputs coupled to receive first and second voltage signals, respectively. The voltage-to- time converter includes a comparator configured to compare the first voltage signal and the second voltage signal and to generate a comparator output signal at a first level if the first voltage is greater than the second voltage and at a second level if the second voltage is greater than the first voltage. The voltage-to-time converter further includes an output circuit configured to generate first and second output signals based on the comparator output signal. The output circuit is configured to provide a selected one of the first or second output signals at the first level for a duration dependent on a difference between respective voltages of the first and second voltage signals.

Control system with voltage-to-time converter for combined buck-boost converter using a single inductor

A power converter circuit that includes a switch circuit, and multiple phase and amplifier circuits, may generate a voltage level on a regulated power supply node of a computer system. The amplifier circuits may generate respective demand currents using a voltage level of the regulated power supply node and a reference voltage. In response to activation of a multi-phase operating mode, the switch circuit may short the outputs of the amplifier circuits to generate a common demand current. The multiple phase circuits may sequentially source current to regulated power supply node using the common demand current.

Reconfigurable multi-phase power converter

A DC-DC converter that provides both buck and boost voltages using a single inductor is disclosed. The DC-DC converter includes an H-bridge circuit having an inductor having first and second terminals, and a number of switches. The switches include a first switch coupled between the second inductor terminal and a boost voltage node, a second switch coupled between the second inductor terminal and a buck voltage node, and a third switch coupled between the first inductor terminal and an input voltage node. A control circuit is coupled to activate the switches in accordance with a number of different phases such that a buck voltage (e.g., less than the input voltage) is provided on the buck voltage node, while a boost voltage (e.g., greater than the input voltage) is provided on the boost voltage node.

Combined buck-boost converter using a single inductor

Disclosed examples include inverting buck-boost DC-DC converter circuits with a switching circuit to alternate between first and second buck mode phases for buck operation in a first mode, including connecting an inductor and a capacitor in series between an input node and a reference node to charge the inductor and the capacitor in the first buck mode phase, and connecting the inductor and the capacitor in parallel between an output node and the reference node to discharge the inductor and the capacitor to the output node. For boost operation in a second mode, the switching circuit alternates between connecting the inductor and the capacitor in series between the input node and the reference node to discharge the inductor and charge the capacitor in a first boost mode phase, and connecting the inductor between the input node and the reference node to charge the inductor and connecting the capacitor between the first output node and the reference node to discharge the capacitor to deliver power to the output node in a second boost mode phase.

Buck-boost DC-DC converter

A power converter circuit included in a computer system may charge and discharge a switch node coupled to a regulated power supply node via an inductor. During a charge cycle, the power converter circuit may generate a reference ramp signal that has an initial voltage level greater than that of the switch node. The power converter may also generate a sense ramp signal using the voltage level of the switch node, and halt the charge cycle using results of a comparison of the respective voltage levels of the reference ramp signal and the sense ramp signal.

Power converter with on-resistance compensation

In an example, a dual-phase inverting buck-boost power converter for use with at least first and second energy storage elements includes an inverting buck-boost power converter and an inverting boost converter. In an example, the inverting buck-boost power converter is coupled between an input node and an output node of the dual-phase inverting buck-boost power converter and includes a first plurality of switches operable to couple to the first energy storage element, wherein the inverting buck-boost power converter is operable to supply a first load current. In an example, the inverting boost converter is coupled in parallel with the inverting buck-boost power converter between the input node and the output node of the dual-phase inverting buck-boost power converter and includes a second plurality of switches operable to couple to the first and the second energy storage elements, wherein the inverting boost converter is operable to supply a second load current.

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Unterschleissheim, Germany

Nicola Rasera