Friday, October 14, 2016

High Efficiency Step Down Isolated Supply

60W AC-DC adapter, synchronous rectification, fixed frequency current mode PWM controller. Very Low Quiescent Burden, Efficiency above 85%. That's Green.

STMicroelectronics - EVALSTSR30-60W. Synchronous rectification using L6668 and STSR30.

EVALSTSR30-60W: 60W AC-DC adapter
EVALSTSR30-60W: 60W AC-DC adapter

The converter works in both Continuous and Discontinuous conduction mode depending on the input voltage (the circuit has a wide input voltage range) and the output load. The 68-kHz switching frequency provides a good compromise between the transformer size and the harmonics of the switching frequency, optimizing input filter.

High Efficiency Step Down Isolated Supply

The input section includes protection elements (varistor, fuse and NTC for inrush current limiting), a standard Pi-filter for EMC suppression, a bridge and an electrolytic bulk capacitor as the front-end AC-DC converter. The transformer is a layer type, uses a standard ETD34 ferrite core and is designed to have a reflected voltage of 95V. The power MOS is a 700V - 1Ω and a transil clamp network is used for leakage inductance demagnetization.

From STMicroelectronics

Wednesday, October 12, 2016

EMI RFI - ElectroMagnetic Interference

Electromagnetic interference (or EMI, also called radio-frequency interference or RFI when in radio frequency) is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.
 
Electromagnetic interference Wiki

Vertical polarized VHF- UHF biconical antenna

Vertical polarized VHF- UHF biconical antenna
170 – 1100 MHz with omni directional H-plane pattern

Who would know better about Radio Frequency Interference and ElectroMagnetic Interference more than the Hams or Amateur Radio Community.

If they have to communicate effectively using limited resources, they have to deal with EMI/RFI effectively, While they build their equipment or combat Noise from other Machines and Installations nearby.

This problem needs more practical involvement and experimentation to learn, compared to learning something like Digital Electronics.

Equipment and Electricals like SMPS, AC/DC Drives, Motors, Solenoids and CFL Lamps are to be built/reinforced for low EMI/RFI emission/radiation.

Sensitive Medical Equipment like ECG or even a Aircraft can be seriously affected by Noise.

Radio Frequency Interference (RFI)

Sunday, October 02, 2016

Rambus - IP Provider - Semiconductors

Technology licensing company. Manages and Provides Licenses to IP Intellectual property and Patents of semiconductor Technology. Founded in 1990.  XDR, DDR3, RDRAM and FlexIO are some of the Technology Solutions from Rambus.

Rambus - IP Provider - Semiconductors

"Beginning with edge-lit back lighting, Rambus has pioneered light guide-based design solutions for a broad range of LED lighting applications, enabling a new level of styling, efficiency and control of light."

LED lighting technology - Rambus

LED lighting technology

Rambus' lighting solutions enable manufacturers to use fewer or lower-cost LEDs in their general lighting products while delivering superior light quality and output.