Linear Technology Patent Grants

Controlling switching circuits to balance power or current drawn from multiple power supply inputs

Granted: July 11, 2017
Patent Number: 9705325
Novel techniques for balancing power or current drawn from multiple power supply inputs by controlling switching circuits associated with the respective power supply inputs. Each switching circuit may be controlled so as to limit current in its transformer or inductor in each switching cycle to a peak or average current value common to all switching circuits.

System and method for clock generation with an output fractional frequency divider

Granted: July 4, 2017
Patent Number: 9698800
A system and a method generate clock signals using an output divider with modulus steps of half-integers (i.e., the output circuit includes a divider which divides by one or more of 2, 2.5, 3, 3.5, 4 . . . ).

Laser drilling encapsulated semiconductor die to expose electrical connection therein

Granted: June 27, 2017
Patent Number: 9691681
A method of making an integrated circuit package that contains a semiconductor die having one or more electrical connections to an electronic circuit within the semiconductor die. The method may include: encapsulating the semiconductor die and its electrical connections in non-electrically conductive, encapsulation material; laser drilling the encapsulation material to expose one of the electrical connections within the integrated circuit package, thereby creating a via opening in an…

Notch filter for ripple reduction

Granted: June 20, 2017
Patent Number: 9685933
A notch filter is controlled synchronously with a chopper to filter out chopping ripple. In one embodiment, the notch filter is coupled to the differential output of the chopper and includes a sampling capacitor, a hold capacitor, and a second set of switches between the sampling capacitor and the hold capacitor. The second set of switches is temporarily closed once per chopper switching cycle to transfer charge from the sampling capacitor to the hold capacitor such that the ripple from…

High voltage selector circuit with no quiescent current

Granted: June 20, 2017
Patent Number: 9685938
A maximum voltage selection circuit may include multiple inputs, each for receiving a different input voltage, an output for delivering the highest of the input voltages, and a voltage selection circuit. The voltage selection circuit may automatically select the input having the largest voltage magnitude, automatically deliver the voltage at the selected input to the output, and not draw quiescent operating current from any of the inputs. For each and every unique combination of two of…

Detecting faults in hot-swap applications

Granted: June 6, 2017
Patent Number: 9671465
Circuitry for detecting faults in a system for supplying power from an input node to an output node and having at least one switch coupled between the input node and the output node. The fault detecting circuitry is configured for indicating a fault condition of the switch when the switch is commanded to turn on and at least one of the following conditions is detected: a voltage across the switch exceeds a predetermined value or a value of the switch control signal is insufficient to…

Transition timing control for switching DC/DC converter

Granted: May 30, 2017
Patent Number: 9667264
A device is configured to control a transition timing of a switching DC/DC converter for providing power to a load device. The load device has a first operational phase that is sensitive to external noise and a second operational phase that is immune to the external noise. The device includes an input terminal coupled to an external device to receive a start signal of the first operational phase for the load device. The device also includes control circuitry configured to, responsive to…

PSE controller in PoE system detects different PDs on data pairs and spare pairs

Granted: May 30, 2017
Patent Number: 9667429
A PSE includes a PSE controller that performs a handshaking routine with any PDs connected to the data wire pairs and spare wire pairs and applies power to the data wire pairs and spare wire pairs, via a switch, if certain conditions are met. Two different levels of currents are supplied to different terminals of the PSE controller that are connected to the data wire pairs and the spare wire pairs, and the resulting voltages are measured. The voltages are used to determine the PD…

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.