Loops major current

Figure 3-59 The major current loops within the major switching power supply topology types (a) the nonisolated buck converter (h) the nonisolated boost converter (c) the transformer-isolated converter.

These ac current loops should be routed before any other traces in the power supply. The three major components that make up each loop the filter capacitor, the power switch or rectifier, and the inductor or transformer must be located adjacent to one another. The components must also be oriented such that the current path between them is as short as possible. A good example of a layout of the power section of a buck (or step-down) converter can be seen in Figure 3-60. 

As a real-life example of how apparently small-sized circuits can cause major EMI problems, consider a circular current loop (diameter <3C wavelength) enclosing an area A (in m2) carrying an ac current of amplitude I (in amperes) and of frequency f (in Hz). Its field pattern can be broken up into a near-field (x < /./2tt) and a far-field (x > /./2tt). The far-held (the electromagnetic wave) at a distance x from the center of the coil, when calculated in the plane containing the loop, can be shown to be... 

Another major source of noise is the loop consisting of the output rectifiers, the output filter capacitor, and the transformer secondary windings. Once again, high-peak valued trapezoidal current waveforms flow between these components. The output Alter capacitor and rectifier also want to be located as physically close to the transformer as possible to minimize the radiated noise. This source also generates common-mode conducted noise mainly on the output lines of the power supply. 

Fig. 1. Major oceanographic features 1. Canary Current, 2. Gulf Stream, 3. North Atlantic Current, 4. Sargasso Sea, 5. North Atlantic Gyre, 6. Labrador Current, 7. Loop Current, 8. North Pacific Gyre, 9. South Equatorial Current, 10. Benguela Current, 11. Humboldt Current, 12. Antilles Current, 13. Florida Current, 14. Brazil Current, 15. Kuroshio, 16. Antarctic West Wind Drift.

Makharia et al., 2005]. These spectra display a major loop in the Z" versus Z plot that cuts the Z axis at some frequency in the range 0.1-1 Hz, followed by an inductive loop that cuts the Z axis again at a much lower frequency. This frequency response of the interfacial faradaic process likely reflects variations of ORR current in response to a cychc potential perturbation, originating from two effects of the potential on ORR rate, which are well resolved by their different response times. A relevant expression describing this behavior is likely of the form... 

Close-looping an overunity EM system has very special Dirac sea hole current phenomena involved and special techniques are required. Bedini and the present author have filed a patent application on the major process required, and the details will be released a year from that filing. 

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