National Instruments Corporation

Chin-Hong Cheah

John G Banaska

Chuen-Ming Tan

Eric Hartner

Tatt-Wee Oong

A multiphase current-sharing configuration may include at least two power supplies providing respective output-currents in the current-sharing configuration. One or more of the power supplies may itself be a multiphase power supply. A first power supply of the current-sharing configuration may detect a phase difference between an external control signal provided to the first power supply to control the output voltage of the first power supply, and an internal control signal provided by a VCO of the first power supply. The phase difference may be provided to an integrator to cause the internal control signal to track the external control signal when the external control signal is available, and maintain a present operating frequency of the internal control signal in case the external control signal is lost, in which case the internal control signal may be used to uninterruptedly control the output voltage of the first power supply.

LLC power supply current-sharing and frequency locking mechanism

A test system may be used for obtaining accurate remote sense voltage and/or current values. A measurement instrument may provide a regulated stimulus signal to a device under test (DUT) and measure a DUT signal developed at least partially in response to the stimulus signal. A test circuit may superimpose a test signal over the stimulus signal to cause the DUT signal to be developed further in response to the test signal. The DUT signal may be used to derive a resistance of the path that couples the measurement instrument to the DUT. The measurement instrument may include a source measure unit, the stimulus signal may be a regulated voltage, and the DUT signal may be a sense voltage. The harmonics of the DUT signal may be analyzed to determine a correlation between an amplitude of a measured fundamental frequency of the DUT signal and the resistance of the path.

DC resistance measurement contact checking via alternating current high frequency injection

Circuits and methods for electronically adjusting an effective inductance of one or more primary inductors in a circuit. The circuit may include a plurality of sub-circuits connected in parallel between an input and an output of the circuit. Each sub-circuit may include a primary inductor and an auxiliary inductor inductively coupled to the primary inductor. The circuit may further include first circuitry coupled to the primary inductor, wherein the first circuitry configured to introduce an oscillating first voltage across the primary inductor; and second circuitry coupled to the auxiliary inductor, wherein the second circuitry is configured to introduce an oscillating second voltage across the auxiliary inductor. The amplitudes of the second voltages may be selected to reduce a difference between effective inductances of the primary inductors.

Electronically adjustable inductor circuit

Circuits and methods for operating a programmable load circuit that includes a plurality of sub-circuits connected in parallel between an input and an output. Each sub-circuit may include an inductor, a load, and a switch coupled to the inductor. Each switch may be configurable in a first state and a second state, wherein the inductor is either connected to the output through the load or connected to the output through a connection that bypasses the load. The switches of the plurality of first sub-circuits may be programmable to periodically switch between the first state and the second state according to a duty cycle, and the switches may be out of phase with each other by a predetermined amount. The duty cycle may be programmable to tune the load of the programmable load circuit.

Multi-phase noise cancelled adjustable switched mode programmable load

A fan noise suppression circuit may be coupled between a power source and a power input to at least one fan. The fan noise suppression circuit may include an adjustable current source coupled to the power source. The adjustable current source may provide a voltage output and a current output based on a power output of the power source. The fan noise suppression circuit may include a feedback controller coupled to an output of the adjustable current source. The feedback controller may be configured to compare the voltage output to a reference voltage and provide an error value to the adjustable current source, wherein the adjustable current source may adjust the current output based on the error value.

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Pulau Pinang, Malaysia

Chin-Hong Cheah