Texas Instruments Corporation

Ashish Kumar

Yogesh Kumar Ramadass

Haoquan Zhang

Manish Bhardwaj

Capacitively isolated current-loaded or current-driven charge pump circuits and related methods transfer electrical energy from a primary side to a secondary side over a capacitive isolation boundary, using a controlled current source to charge isolation capacitors with constant current, as opposed to current impulses, while maintaining output voltage within tolerance. The charge pump circuits provide DC-to-DC converters that can be used in isolated power supplies, particularly in low-power applications and in such devices as sensor transmitters that have separate electrical ground planes. The devices and methods transfer electrical energy over an isolated capacitive barrier in a manner that is efficient, inexpensive, and reduces electromagnetic interference (EMI).

Power transfer over an isolated capacitive barrier with controlled current

In a described example, a circuit includes a sensor, a controller and an amplifier. The sensor has a sensor input and a sensor output. The sensor input is adapted to be coupled to a chassis of a switch-mode power supply (SMPS). The controller has an input, a timing output and a level output. The input of the control circuit is coupled to the sensor output. The amplifier has a timing control input, a level control input and an amplifier output. The level control input is coupled to the level output of the controller. The timing control input is coupled to the timing output, and the amplifier output is coupled to the sensor input. The amplifier is configured to provide compensation pulses at the amplifier output having magnitude and timing to reduce common-mode noise on the chassis.

Active noise filtering for switch mode power supplies

A system includes an input voltage supply and a switching converter coupled to the input voltage supply. The switching converter includes a transformer having a primary coil and a secondary coil. The switching converter also includes a Y-rated capacitor with a top plate and a bottom plate, wherein the top plate is coupled to a first end of the secondary coil. The switching converter also includes a push-pull current source coupled to the bottom plate of the Y-rated capacitor. The switching converter also includes a controller coupled to the push-pull current source.

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Santa Clara, CA, United States of America

Ashish Kumar