Linear Technology Patent Grants

Precision temperature measurement devices, sensors, and methods

Granted: May 23, 2017
Patent Number: 9658118
A precision temperature sensing system includes a heater and a sensing element disposed on a semiconductor substrate. A power source drives the heater on a periodic basis according to a received clock signal. The sensing element senses the heat emitted by the heater and diffused through the semiconductor substrate. Processing circuitry coupled to the sensing element adjusts a phase of the periodic heater driving signal based on the heat sensed by the sensing element. The processing…

Switching of conductor pair in power over ethernet system

Granted: May 23, 2017
Patent Number: 9660456
Technique for providing power to a powered device (PD) over a cable having first and second sets of twisted pairs, such as signal pairs and spare pairs. Power Sourcing Equipment (PSE) circuitry is coupled via a first switch to the second set, e.g. to the spare pairs. A switch control circuit turns the first switch off to enable the PSE circuitry to perform a prescribed operation in connection with the PD over only the first set, e.g. over the signal pairs, and turns the first switch on…

Distortion compensation circuit

Granted: May 23, 2017
Patent Number: 9660856
A method and system of compensating for distortion in a baseband in-phase (I) and a corresponding baseband quadrature (Q) signal. The circuit includes an in-phase I attenuator configured to attenuate the baseband in-phase I signal and an in-phase Q attenuator configured to attenuate the baseband Q signal. There are one or more circuits that are configured to receive the attenuated in-phase I signal and the attenuated baseband Q signal. Each circuit performs a different calculation based…

Chopper-stabilized square cells

Granted: May 2, 2017
Patent Number: 9639719
An RMS-DC converter includes a chopper-stabilized square cell that eliminates offset, thus enabling high-bandwidth operation. The chopper-stabilized offset requires only a small portion of the circuitry (i.e., a single component square cell) which operates at high frequencies, and is amenable to using high-bandwidth component square cells. Using the chopping technique minimizes required device sizes without compromising an acceptable square cell dynamic range, thereby maximizing the…

Maintaining LED driver operating point during PWM off times

Granted: May 2, 2017
Patent Number: 9642200
A method and system of driving an LED load. There is a power stage that 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. There is a feedback circuit that is configured to generate the operating point signal, which causes the power stage to deliver a level of current indicated by the control signal, when the PWM signal is ON. A store and hold circuit is…

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…