A low-power DC-DC converter with digital spread spectrum for reduced EMI
Bibliographic record
Abstract
This paper presents a 1.8 V step-down DC-DC converter prototype with a hybrid delay-line based digital pulse-width modulator. A spread spectrum clock generation scheme is demonstrated for reducing EMI. The switching frequency of the buck converter prototype is automatically varied from 1.74 MHz to 2.84 MHz in 128 steps using a pseudo-random 512 cycle pattern, resulting in a 23 dB reduction in the conducted EMI peak. The digital pseudo-random pattern is converted to an analog reference voltage using a low-cost one-bit delta-sigma DAC having an over-sampling rate of 4096. The DAC output modulates the reference voltage of an LDO that regulates the delay-line supply voltage. It is shown that the effective duty-cycle changes by only 0.27 % over the frequency range. With spread spectrum mode enabled, the inductor current ripple becomes time-dependent but the efficiency degrades by less than 0.1%. The proposed architecture can be applied to a wide variety of state-of-the-art digital controllers that rely on delay-line based pulse width modulators.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".