Abstract: 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 circuitry determines a temperature based on a thermal diffusivity (TD) of the semiconductor substrate, the adjusted value of the phase, and a known distance between the heater and the sensing element. A second temperature sensor can be disposed on the same substrate as the precision temperature sensing system, and calibrated based on temperature measurements obtained while applying a reference frequency signal to the precision sensing system.

Abstract: 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 to enable the PSE circuitry to perform the prescribed operation in connection with the PD over the first and second sets.

Abstract: 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 on predetermined equations configured to determine the IM2, HD2@0°, HD2@90°, IM3@0°, IM3@90°, HD3@0°, and HD3@90°. The distortion compensation circuit is configured to use the result of at least one of the calculation circuits to generate I and Q distortion compensation signals.

Abstract: 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 configured to store an information indicative of a level of the operating point signal just after the PWM signal is turned OFF and cause the operating point signal to be at that level just before the PWM signal is turned ON.

Abstract: 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 square cell bandwidth. The RMS-DC converter consumes less power than conventional RMS-to-DC converters that requires a high-frequency variable gain amplifier.

Abstract: 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 circuit coupled to the output of the transconductance amplifier is configurable to include a selected number of resistive elements having selected resistance values and a selected number of capacitive elements having selected capacitance values. The configuration of the RC circuit is carried out to provide an RC thermal model that reproduces a desired thermal behavior of the semiconductor element.

Abstract: 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 circuit coupled to the output of the transconductance amplifier is configurable to include a selected number of resistive elements having selected resistance values and a selected number of capacitive elements having selected capacitance values. The configuration of the RC circuit is carried out to provide an RC thermal model that reproduces a desired thermal behavior of the semiconductor element.

Abstract: 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 detects the relative currents through the resistors. If the currents are the same, then the PSE knows the PD is able to receive power via the four wire pairs. The PSE then applies the full PoE voltage to the first and second wire pairs and connects the third and fourth wire pairs to a low voltage via a MOSFET.

Abstract: 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 remainder of the current is used to control the pull-down transistor in the Class AB buffer, so the driver is very efficient. The portion of the driver circuit between the input of the driver circuit and the base of the NPN driver transistor is an inverting circuit. The driver can properly operate with an input voltage within two diode drops of ground.

Abstract: 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 auxiliary switching converter coupled in parallel with the main switching converter and configured to operate at a second and different switching frequency and source fast transient high frequency current to the load device.

Abstract: An anti-lash nut assembly for installation on a threaded rod and including a lead nut, a collar, and a spring positioned between the lead nut and the collar. The lead nut has a set of tabs extending radially outward from a rear end of the body. The collar has a set of clearance slots on an inside surface. The set of clearance slots are configured for sliding of the set of tabs through the clearance slots in the rear direction. The collar has a set of ramps on an inside surface. Each of the set of ramps is configured for engagement with each of the set of tabs to prohibit axial movement of the collar in the rear direction.

Abstract: 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 threshold voltage. In one implementation, changing the switching frequency is achieved in increasing (e.g., doubling) the frequency of the clock signal, as needed. The frequency of the clock signal need only be changed for a predetermined time period.

Abstract: 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.

Abstract: 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 feedback reference signal just after the PWM signal is turned OFF. The feedback path causes the voltage across the output capacitance element to be at the first voltage level just before the PWM signal is turned ON.

Abstract: 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 the body terminal of the FET.

Abstract: 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 primary side signal values, regulates a constant average voltage at the output node. An optional second feedback control loop, responsive only to primary side signal values, reduces voltage ringing at the output node.

Abstract: 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 disconnected and does not draw current. When the first load comes out of the standby mode and into an active mode, the converter supplies a relatively high current to the second load and the first load. In this way, the first load, if a processor, can be already booted up at the time the second load becomes active.

Abstract: 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 the PDs to power the loads, such as processors, in a low power standby mode. The voltage regulator in the PD for the low power mode may be an efficient linear regulator, and the voltage regulator in the PD for the full voltage mode may be a switching regulator. Thus, there is improved efficiency.

Abstract: 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, which is at the duty cycle of the regulator, to a second RC filter, which blocks a second DC component. The second AC component is much larger than the first AC component and does not contain switching noise. The large second AC component, the smaller “noisy” first AC component, and the first DC component are applied to the first RC circuit to create a low-noise inductor current signal.

Abstract: 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 frequency. A detector in the transmit side wirelessly detects whether there is sufficient current being generated in the receiver side to achieve regulation by a voltage regulator powering the load. This point is achieved when the transmitter inductor peak voltage suddenly increases as the driving pulse width is ramped up. At that point, the pulse width is held constant for optimal efficiency.