Linear Technology Patent Grants

Inverting amplifier receiving negative feedback voltage in voltage regulator

Granted: May 22, 2018
Patent Number: 9977446
In the example of a voltage regulator outputting a negative voltage, its feedback voltage will also be negative. The feedback voltage is typically created using a resistor divider. A controller IC is powered by only a positive voltage and receives the negative feedback voltage at a high impedance input of an inverting amplifier. Therefore, the inverting amplifier does not load the resistor divider, resulting in an accurate regulated output voltage. The inverting amplifier converts the…

Synchronized charge pump-driven input buffer and method

Granted: May 15, 2018
Patent Number: 9973079
An integrated circuit includes (a) an analog-to-digital converter operated according to a first clock signal; and (b) a charge pump circuit providing a negative power supply voltage to the integrated circuit, the charge pump circuit being operated according to a second clock signal having a frequency that is different from a frequency of the first clock signal, such that a noise level introduced by the charge pump into the analog-to-digital converter is less than the average noise level…

Detecting ground isolation fault in ethernet PoDL system

Granted: May 8, 2018
Patent Number: 9967104
Circuits and techniques are described for detecting a ground fault leak between the PSE and the PD. Prior to PoDL voltage being applied to the PD, a test switch is temporarily closed for sensing a voltage drop in a loop between the positive terminal of the PSE voltage source and any ground leakage path between the PSE and the PD. If the resistance of the ground leakage path is below a certain threshold, a fault is declared. A similar test may be performed without a test switch by…

Predictive ripple-cancelling signal into error amplifier of switch mode power supply

Granted: May 8, 2018
Patent Number: 9966832
A predicted ripple in the feedback voltage of a switching converter is generated, based on the ripple over a certain number of recent switching cycles. The DC portion of the feedback voltage is filtered out. This predicted feedback voltage ripple is then added to a fixed reference voltage to create a compensated reference voltage. The compensated reference voltage is applied to the non-inverting input of an error amplifier, and the feedback voltage (having a DC component and ripple) is…

Switchable termination with multiple impedance selections

Granted: May 1, 2018
Patent Number: 9960752
Multiple termination impedance values are provided in a switchable termination circuit so as to accommodate multiple transmission line characteristics. In one example, a termination matching circuit includes first and second nodes, a series interconnection of a first switch and a first impedance coupled between the first and second nodes, and another series interconnection of a second switch and a second impedance coupled between the first and second nodes. First and second control…

Timing synchronization for wireless networks

Granted: April 24, 2018
Patent Number: 9955443
A system for synchronizing nodes in a wireless network comprises a first node and a second node. The first node comprising a transmitter, a receiver, and a first time keeper. The second node comprising a transmitter, a receiver, a second time keeper, a timing error measurer for making a timing error measurement between the first time keeper and the second time keeper. The second timekeeper is adjusted to target minimizing the timing error measurement.

Adaptive slope compensation for current mode switching power supply

Granted: February 20, 2018
Patent Number: 9899921
A current mode switching converter includes a transistor switch, an inductor configured to conduct a ramping inductor current as the transistor switch is turned on and off at a particular duty cycle, and an inductor current sensor generating a current sense signal. The current sense signal has an up-slope portion and a down-slope portion. A separate ramp generator generates a ramp voltage for each switching cycle. A slope compensation circuit compensates the ramp voltage, depending on…

Detection and classification scheme for power over ethernet system

Granted: February 20, 2018
Patent Number: 9897981
In a method performed by a PoE system, a PSE provides data and operating voltage over Ethernet wires to a PD. Before the full PoE voltage is supplied, the PSE generates a low current signal received by the PD. A circuit in the PD, connected across its input terminals, has a characteristic analog response to the PSE signal corresponding to the PD's PoE requirements, such as whether the PD is a Type 1 or Type 2 PD. The circuit may be a certain value capacitor, zener diode, resistor, or…

Active differential resistors with reduced noise

Granted: January 9, 2018
Patent Number: 9866245
A method and system of providing an active differential resistor. The active differential resistor includes a diode having a first node and a second node. There is a capacitor coupled in series between the first node of the diode and an input of the active differential resistor. There is a current source coupled across the first node and the second node of the diode and configured to forward bias the diode such that a Johnson-Nyquist noise of the active differential resistor is replaced…

System with sleep and wake up control over DC path

Granted: January 2, 2018
Patent Number: 9860072
A system includes a master and a slave coupled via a wire pair for transmitting differential data. The master and slave are each powered by a local DC power supply. In a normal mode, a DC voltage and differential data are supplied over the same wire pair. The differential data is processed by a PHY AC-coupled to the wire pair. To enter a low power sleep mode, such as due to a temporary non-use of the system, the master interrupts the DC voltage on the wire pair, which signals to the…

Power over data lines detection and classification scheme

Granted: January 2, 2018
Patent Number: 9859951
A PoDL system includes a PSE connected via a wire pair to a PD, where differential data and DC power are transmitted over the same wire pair. Typically, low voltage/current detection and classification routines are required upon every powering up of the system to allow the PD to convey its PoDL requirements to the PSE. Various techniques are described that simplify or obviate such start-up routines or enable increased flexibility for the PoDL system. Such techniques include: ways to…

Analog to digital conversion yielding exponential results

Granted: January 2, 2018
Patent Number: 9859909
A method and system of an analog to digital conversion having an exponential result are provided. An analog input signal is received by the ramp ADC. The analog input signal is converted into an N-bit digital signal having a linear relationship with the analog input signal. An internal gated clock signal is generated based on the received first clock signal. The gated clock signal is used as an input to an M-bit register. An output of the M-bit register is multiplied by a predetermined…

PoDL system with active dV/dt and dI/dt control

Granted: December 26, 2017
Patent Number: 9853838
A Power Over Data Lines (PoDL) system includes Power Sourcing Equipment (PSE) supplying DC power and differential Ethernet data over a single twisted wire pair to a Powered Device (PD). Due to start-up perturbations, PD load current variations, and other causes, dV/dt noise is introduced in the power signal. Such noise may be misinterpreted as data unless mitigated somehow. Rather than increasing the values of the passive filtering components conventionally used for decoupling/coupling…

1-wire bus PD detection and classification scheme for ethernet PoDL

Granted: December 26, 2017
Patent Number: 9851772
A PoDL system includes a PSE supplying DC power and Ethernet data over a single twisted wire pair to a PD. Prior to coupling the DC voltage source to the wire pair, the PD needs to receive sufficient power to perform a detection and classification routine with the PSE to determine whether the PD is PoDL-compatible. The PSE has a low current, pull-up current source coupled to a first wire in the wire pair via a first inductor. This pull-up current charges a capacitor in the PD to a…

Method of manufacturing an anemometer used for determining a fluid flow

Granted: December 26, 2017
Patent Number: 9851372
An anemometer and method for analyzing fluid flow is described. In one embodiment, a transistor sensor is heated by applying power to cause its base-emitter junction to rise from an ambient first temperature to a second temperature. The power is removed, and the Vbe is measured at intervals as the junction cools. The Vbe equates to a temperature of the junction. The temperature exponentially decreases, and the time constant of the decay corresponds to the fluid flow velocity. A best fit…

Input current conditioner for precision coulomb counting

Granted: December 19, 2017
Patent Number: 9846196
A method and system of counting coulombs drawn from a power source by a load. A reference current source regulates the current drawn by the load at any given time to be either zero or a predetermined fixed amount. A comparator controls a time the switch is closed and open. When the switch is closed, coulombs are allowed to be drawn from the power source, and prevented to be drawn when the switch is open. An oscillator generates a clock signal during the time the switch is closed. A…

Fast transient power supply with a separated high frequency and low frequency path signals

Granted: November 28, 2017
Patent Number: 9831781
A power interface device includes a main switching converter, an auxiliary switching converter, and a feedback sense circuit. The main switching converter is coupled to an input terminal and an output terminal and configured to operate at a first switching frequency to source a low frequency current from the input terminal to the output terminal. The auxiliary switching converter is coupled to the input terminal and the output terminal in parallel with the main switching converter and…

Voltage regulation in resonant power wireless receiver

Granted: November 21, 2017
Patent Number: 9825553
A control system is provided for controlling a power receiving circuit which is configured for receiving power wirelessly and producing an output voltage. The power receiving circuit has a resonant LC circuit including an inductive element and a capacitive element coupled in parallel. The control system includes a switching circuit coupled in parallel to the resonant LC circuit, and a feedback loop circuit configured for regulating the output voltage by controlling duration during which…

System and method for synchronization among multiple PLL-based clock signals

Granted: November 7, 2017
Patent Number: 9811113
A method synchronizes clock signals generated by a system that includes multiple PLLs that are connected in parallel and output frequency dividers driven by the PLLs. The system receives a common frequency reference signal and a common synchronization signal. Each PLL may have a reference signal frequency divider. The reference frequency divider may be phase-reset, for example, by a transition to a first logic state in the synchronization signal, and the output frequency dividers are…

Monitoring cells in energy storage system

Granted: October 17, 2017
Patent Number: 9793734
A system for monitoring an energy storage system composed of multiple cells connected in series has a chain of monitors including at least first and second monitors. The first monitor is configured for monitoring at least a first cell in the energy storage system to produce first monitored data. The second monitor is configured for monitoring at least a second cell in the energy storage system to produce second monitored data. The first monitor is further configured for transferring the…