Linear Technology Patent Grants

Class AB inverting driver for PNP bipolar transistor LDO regulator

Granted: April 25, 2017
Patent Number: 9632519
A driver circuit for a PNP power transistor in an LDO regulator uses a Class AB (push-pull) buffer to supply the necessary base current to an NPN driver transistor, where the NPN driver transistor has its collector connected to the base of the PNP power transistor. A front end circuit of the driver, coupled to drive the Class AB buffer, uses a current diverting transistor, where a first portion of the current is used to control the pull-up transistor in the Class AB buffer, and the…

MOSFET protection using resistor-capacitor thermal network

Granted: April 25, 2017
Patent Number: 9634480
A circuit for protecting a semiconductor element is provided in a system for supplying power from an input node to an output node. The circuit has an analog multiplier responsive to a voltage across the semiconductor element and a current flowing through the semiconductor element to produce an output voltage. A transconductance amplifier is coupled to an output of the analog multiplier for receiving the output voltage of the analog multiplier to produce an output current. An analog RC…

MOSFET protection using resistor-capacitor thermal network

Granted: April 25, 2017
Patent Number: 9634481
A circuit for protecting a semiconductor element is provided in a system for supplying power from an input node to an output node. The circuit has an analog multiplier responsive to a voltage across the semiconductor element and a current flowing through the semiconductor element to produce an output voltage. A transconductance amplifier is coupled to an output of the analog multiplier for receiving the output voltage of the analog multiplier to produce an output current. An analog RC…

Detection scheme for four wire pair Power Over Ethernet system

Granted: April 25, 2017
Patent Number: 9634844
In a method performed by a PoE system, a PSE is able to detect whether a PD is compatible for receiving power via four wire pairs in the standard Ethernet cable. The PSE provides a current limited voltage to a first and second pair of wires in the cable, during a detection phase, to detect a characteristic impedance of the PD. In the PSE, a first resistor is connected to a third wire pair and a second resistor is connected to a fourth wire pair. During the detection phase, the PSE…

Control architecture with improved transient response

Granted: April 18, 2017
Patent Number: 9627976
A power supply system includes a power source; a load device configured to receive power from the power source; and a power interface device coupled to the power source and the load device and configured to change a first voltage provided by the power source to a second voltage for operating the load device. The power interface device include a main switching converter configured to operate at a first switching frequency and source low frequency current to the load device and an…

Circuit and method for dynamic switching frequency adjustment in a power converter

Granted: April 4, 2017
Patent Number: 9614436
A method and a circuit dynamically adjust a frequency of a clock signal that drives the operations of a power converter. The method includes (a) detecting a change from a predetermined value in an output voltage of the power converter; and (b) upon detecting the change, changing the frequency of the clock signal so as to restore the output voltage. The change, such as a load step-up, may be detected by comparing a feedback signal generated from the output voltage and a predetermined…

Low power radio receiver

Granted: March 14, 2017
Patent Number: 9595991
A frequency converting element includes a mixer and a charge pump. The mixer has first and second input nodes and an output node, and an input code of the charge pump is coupled to the output node of the mixer. The charge pump receives a mixer output signal at the input node of the charge pump, and outputs an amplified version of the mixer output signal.

Maintaining output capacitance voltage in LED driver systems during PWM off times

Granted: March 14, 2017
Patent Number: 9596728
A method and system of driving an LED load. A driver is configured to deliver a level of current indicated by a control signal to the LED load when a PWM signal is ON and stop delivering the level of current when the PWM signal is OFF. An output capacitance element is coupled across a differential output of the LED driver. A feedback path, having a store circuit, is configured to store an information indicative of a first voltage level across the output capacitance element as a stored…

Transconductance (gm) boosting transistor arrangement

Granted: February 14, 2017
Patent Number: 9571052
A circuit may increase input transconductance. An input stage may include a field effect transistor (FET) that has a gate, source, drain, and body terminal. An amplifier may generate an amplified version of the input voltage received that is applied to the body terminal of the FET. Application of the amplified version to the body terminal of the FET may increase the transconductance of the FET compared to what it would be in the same circuit without the amplified version being applied to…

Methods and systems for control of DC-DC converters

Granted: February 7, 2017
Patent Number: 9564820
Switching regulator methods and systems for supplying output current at a regulated voltage level to a load. The regulator has a primary side that is galvanically isolated from a secondary side. The regulator includes a transformer having a primary winding on the primary side and a secondary winding on the secondary side, coupled to a load. A switch, coupled to the primary winding, controls current flow through the primary winding. A first feedback control loop, responsive only to…

Powered device, using power over ethernet, with dedicated low current and high current paths for loads

Granted: January 17, 2017
Patent Number: 9547318
In a method performed by a Power Over Ethernet (PoE) system, Power Sourcing Equipment (PSE) provides data and voltage over Ethernet wires to a Powered Device (PD). The PD converts the PSE voltage to a regulated voltage by at least one DC-DC converter in the PD. A first load in the PD, such as a processor, operates in a standby mode during a standby period and draws a low current from the converter via a low current path. During this standby period, a high current load in the PD is…

Power over ethernet power sourcing equipment provides low voltage output for increased efficiency in low power mode

Granted: January 3, 2017
Patent Number: 9535437
In a PoE system in an automobile, Power Source Equipment (PSE) is connected to Powered Devices (PDs) to provide data and power via Ethernet wires. When the ignition switch is on, the full PSE voltage, such as 44 volts, is supplied to the PDs, and the voltage is regulated by the PDs to power one or more loads in the PD. During a standby mode, such as when the ignition switch is off, the PSE is controlled to output a lower voltage of, for example, 5 volts, and the voltage is regulated by…

Driver for wireless power transmitter sensing required transmit power for optimum efficiency

Granted: December 20, 2016
Patent Number: 9524824
An auto-resonant driver for a transmitter inductor drives the inductor at an optimal frequency for maximum efficiency. The transmitter inductor is magnetically coupled, but not physically coupled, to a receiver inductor, and the current generated by the receiver inductor is used to power a load. The system may be used, for example, to remotely charge a battery (as part of the load) or provide power to motors or circuits. A feedback circuit is used to generate the resonant driving…

Inductor current sensing in a buck converter using multiple filters

Granted: December 20, 2016
Patent Number: 9525351
In a current mode switching power supply, current through the inductor needs to be sensed to control the peak current. The inductor current includes a DC component and an AC component containing switching noise. To reduce the switching noise, the actual inductor current is sensed to generate a signal, and a first AC component is attenuated by a first RC circuit while not attenuating a first DC component. A second AC component is derived by applying the rectangular wave switch voltage,…

Radio receiver

Granted: November 15, 2016
Patent Number: 9496840
A baseband signal-conditioning architecture applicable to radio receivers uses switched-capacitor techniques to provide high-performance signal conditioning in low-voltage, deep-submicron processes (e.g., 65 nm and below). In the architecture, a first mixer is coupled to an antenna receiving the signal, and outputs a first mixer output signal based on the signal received by the antenna. A buffer coupled to an output of the first mixer outputs a buffer signal based on the first mixer…

Power over Ethernet system where power sourcing equipment detects actual voltage at powered device

Granted: November 8, 2016
Patent Number: 9488997
A Power Over Ethernet (PoE) system, or other power over data lines system, includes Power Sourcing Equipment (PSE) providing combined data and voltage over wires to a Powered Device (PD). Since cable length and PD load currents may not be known, there is a variable voltage drop along the cable between the PSE and PD. Prior to the PD being fully powered up, a test is performed by the PSE to determine the actual resistance or voltage drop of the cable, and the results are stored in a…

Switched capacitor DC-DC converter with reduced in-rush current and fault protection

Granted: November 1, 2016
Patent Number: 9484799
To reduce in-rush currents into a switched capacitor DC/DC converter and detect voltage and current faults, a converter controller is housed along with a current limit series transistor and fault detection circuitry. The series transistor is controlled to limit the in-rush current to a predetermined maximum level during start-up. If the duration of the current limit level, or the time for Vout to achieve a target voltage, exceeds a first threshold time, a first fault detector in the…

Power supply system and method

Granted: October 25, 2016
Patent Number: 9478982
A power control system includes an event data bus configured to carry event information. Several power supply managers are coupled to the same event bus. Each power supply manager has one or more point of load (POL) regulators assigned to it. Each power supply manager communicates event information with other POL power supply managers over the event data bus.

Phase error compensation circuit

Granted: October 25, 2016
Patent Number: 9479142
A method and system of compensating for phase error. A phase error compensation circuit is configured to generate a phase-corrected quadrature Q output signal and a corresponding phase-corrected in-phase I output signal, the circuit includes a first transconductance circuit configured to convert a voltage signal related to an I input voltage signal to an I current signal. A second transconductance circuit is configured to convert a voltage signal related to a Q input signal to a Q…

Configuring signal-processing systems

Granted: October 18, 2016
Patent Number: 9472304
A configurable signal-processing circuit may provide a plurality of selectable signal-processing operations. The configurable signal-processing circuit may have a configuration circuit that provides a configuration code that selects a first signal-processing operation from the plurality of selectable signal-processing operations based on a timing pattern for evaluating an input signal and outputting an output signal.