Analog Devices Global

Analog Devices,inc.

Analog Devices Technology

Analog Devices International Unlimited Company

Analog Devices Global Unlimited Company

Bin Shao

Danzhu Lu

Yanfeng Lu

Junxiao Chen

Kenji Tomiyoshi

Yong Feng

Hua-Jung Yang

Xiaohan Gong

Xing Li

Yogesh Jayaraman Sharma

Jia Chen

Roger Peppiette

James Zhao

Sean Patrick Kowalik

Zhijie Zhu

Langyuan Wang

Song Qin

Guoming Wu

Atsushi Matamura

Olli Haila

Suyi Yao

Linus Sheng

Todd Thomas

Shanshan Yang

Roger Feng

Alan S Walsh

Reed W Adams

Scott D Biederwolf

Apparatus and methods for controlling voltage converter are provided. In an example, a switched-mode DC-DC voltage converter can include an inductor, at least four switches coupled to the inductor and configured to direct current through the inductor to provide a desired output voltage at an output voltage terminal of the voltage converter using an input voltage supply and a ground reference of the converter, and a controller circuit, configured to receive an indication of inductor current through the inductor and to use the slope of the inductor current to control a change between two operating modes of a group of operating modes that include a boost operating mode, a buck operating mode, and a buck-boost operating mode.

Inductor current based mode control for buck-boost converters

An electronic circuit includes parallel linear regulator circuits that support a range of different load currents. The electronic circuit includes a first linear regulator circuit coupled to an output node, a second linear regulator circuit coupled in parallel with the first linear regulator circuit and the output node, and a control circuit. The control circuit is configured to monitor the output node and to suppress or inhibit the second linear regulator circuit from supplying the output node when a representation of load power consumption is below a specified threshold. The first linear regulator circuit is configured to continue to supply a portion of the load power when the representation of load power consumption is above the specified threshold, and the control circuit may disable the second linear regulator circuit when the representation of load power consumption is below the specified threshold.

Load-dependent control of parallel regulators

This application discusses techniques for reducing the energy of an output ripple in a voltage converter at a switching frequency of the voltage converter. In certain examples, an amplitude of a reference voltage can be modulated with a time-varying random value or pseudo-random value to provide a reduction in the energy of the output ripple at the switching frequency of the voltage converter.

Noise reduction in a voltage converter

Techniques for indicating a load level of a DC-DC switching converter are provided. IN an example, a method for real-time load current detection for a switching converter using a discontinuous conduction mode (DCM) of operation can include generating a minimum DCM current threshold based on an reference current source and a duty cycle of the switching converter, receiving a representation of inductor charge current from power switch of the switching converter at a comparator, comparing the representation to the DCM current threshold, and controlling the power switch using a discontinuous conduction mode of the switching converter when a peak of the representation exceeds the minimum DCM current threshold.

Load current detection techniques for discontinuous conduction mode

Apparatus and techniques described herein can include a load circuit comprising a direct current (DC) input terminal, and a source circuit comprising a direct current (DC) output terminal coupled to the DC input terminal of the load circuit. The source circuit can include a source control circuit configured to provide a current-limited DC output voltage and monitor the current-limited DC output voltage to detect an authentication signal provided at the DC output terminal by the load circuit, the load circuit configured to modulate the voltage at the DC output terminal using a pull-down circuit. The load circuit can be configured to compare the supply voltage at the DC input terminal to a reference voltage and, in response, energize other portions of the load circuit when the input current provided the DC input terminal is sufficient as indicated at least in part by the comparison.

Power node communication for device detection and control

An impedance matching circuit is provided for use with a piezotransducer that includes a parasitic capacitor comprising: an inductor coupled in parallel with the parasitic capacitor; a peak and valley detection circuit configured to detect output voltage waveform peaks and valleys; a first switch circuit configured to bias flip the output voltage waveform at a selectable first time relative to a detected peak and at a selectable first time relative to a detected valley; a second switch circuit configured to couple the inductor to the energy storage circuit at a selectable second time following each output voltage bias flip; an energy monitoring circuit to provide an indication of energy flow from the inductor to the energy storage circuit following each output voltage bias flip; and a maximum power point tracking (MPPT) circuit configured to select the first time and the second time based at least in part upon the indicated energy flow.

Piezoelectric energy harvesting system with frequency mismatch tolerance

An electronic circuit can be coupled to an energy harvesting device. The output of the energy harvesting device can provide a damped oscillating waveform elicited from a transient stimulus applied to the energy harvesting device, such as in response to mechanical shock or mechanical impact excitation. A first switch can be coupled between the energy harvesting device and an inductor and configured to selectively connect the input node to the inductor. A second switch can be coupled between the inductor and an energy storage device, the second switch configured to selectively couple the inductor to the energy storage device. A control circuit can be coupled to the first and second switches, such as configured to operate the first and second switches according to one or more of an over bias flip technique, a half bias flip technique, or a bias flip technique.

Piezoelectric impact energy harvesting

Apparatus and methods for providing an ultra-low power voltage converter are provided. In an example, a method can include receiving an ultra-low power command at a voltage regulator circuit from a load, disabling charge transfer of a regulator of the regulator circuit during an ultra-low power mode of operation in response to a first state of the ultra-low power command, detecting a change in the low power command or in a timeout signal, receiving an indication that the output voltage of the regulator is below a low voltage threshold in response to the change, discharging the output voltage of the regulator for a reset interval in response to the indication, and enabling charge transfer of the regulator after discharging the output voltage.

Output voltage hold scheme for ultra low power regulator

Apparatus and techniques for controlling measurement of an electrical parameter of an energy source can be used to obtain information for use in enhancing a power transfer efficiency between the energy source and a load. For example, during a first measurement cycle, information indicative of the electrical parameter of the energy source can be obtained using a measurement circuit during a first sampling duration in which the load is decoupled from the energy source. The information indicative of the obtained electrical parameter can be compared to a threshold. In response to the comparing, a different second sampling duration can be determined for use in obtaining information indicative of the electrical parameter during a subsequent measurement cycle. The information indicative of the electrical parameter of the energy source includes information for use in enhancing the power transfer efficiency between the energy source and the load.

Sampling duration control for power transfer efficiency

An active voltage divider circuit is provided comprising: a first node; a second node; a third node; multiple FET load devices coupled in series between the first node and the second node; multiple first switches, each associated with a different FET load device and configured to selectably couple a respective associated bypass circuit between source and drain of its associated FET load device; and second switch circuitry configured to selectably couple a drain of a FET load device, from among the multiple FET load devices, to the third node.

Active device divider circuit with adjustable IQ

Apparatus and techniques described herein can include using an electronic circuit comprising a rectifier circuit, an open-circuit voltage (OCV) sampling circuit coupled to the output of the rectifier circuit, and a regulator circuit coupled to the output of the rectifier circuit. In an example, an isolation switch can be located between the regulator circuit and the rectifier circuit, the isolation switch configured to isolate the regulator circuit from the rectifier circuit for sampling of the open-circuit voltage by the open-circuit voltage sampling circuit. In another example, a buffer circuit can be used, such as placed in-line with a divider circuit between a divider circuit and an open-circuit voltage sampling capacitor. In this manner, the buffer circuit can provide a low output impedance, isolating the voltage sampling capacitor from the divider circuit.

Energy harvester open-circuit voltage sensing for MPPT

At least one embodiment provides a method for a nanopower boost regulator to startup from an ultra-low-voltage (such as 0.3V&#x2dc;0.5V) for energy harvesting applications. The method does not necessarily require a special process or any external components such as mechanical switches. The startup circuit can include an asynchronous boost circuit to charge up an output with stacked power NMOS transistors, a ring oscillator, and/or a charge pump, along with accompanying circuitry.

Ultra low-voltage circuit and method for nanopower boost regulator

This application discusses, among other things apparatus and methods for a voltage boost circuit. In an example, a voltage boost circuit can include first and second inverters, sharing a first supply node, and sharing a second supply node, a first charge transfer capacitor, configured to couple a first clock signal to the first inverter output, a second charge transfer capacitor, configured to couple a second clock signal to the second inverter output, the second clock signal being out-of-phase with the first clock signal, a first gate drive capacitor, configured to couple the first clock signal to the second inverter input, and a second gate drive capacitor, configured to couple the second clock signal to the first inverter input.

Charge pump

A device to detect an electrical signal is provided. The device includes sensing, output, and pull-down nodes. The device includes a pull-down circuit having a native metal-oxide-semiconductor field-effect transistor (MOSFET) to pull down the output node to approximately a voltage of the pull-down node. The device includes a switch circuit having a junction field-effect transistor (JFET). The JFET turns on the pull-down circuit in response to a voltage of the sensing node being less than a first threshold. The JFET also turns off the pull-down circuit in response to the voltage of the sensing node being greater than the first threshold.

Low quiescent current pull-down circuit

An apparatus comprises a switching power circuit and a control circuit. The switching power converter circuit includes an output port for electrical coupling to a variable load, an input port for electrically coupling to a first energy source, wherein the energy density of the first energy source is insufficient to meet a peak energy requirement of the variable load, an input/output port for electrical coupling to a second energy source, and one inductor electrically coupled to the input port and a circuit node, wherein the electrical coupling is non-switchable. The control circuit is configured to charge the inductor using the first energy source via the input port, to provide energy from the inductor to the load via the output port, and to provide both of, via the input/output port, energy from the inductor to the second energy source and energy from the second energy source to the variable load.

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Shanghai, China

Bin Shao