Close the rail loss and shelf transient on separate boundaries — conditional result
80 W rail loss; 30 mV step; 125 kW shelf input with 5 kW heat. Ideal energy: 1.0 F fails; 1.1 F clears the preliminary screen.derived
| Value kind | derived — Derived values are guide calculations; their result is only as fixed as the stated inputs, scope, and method. |
|---|---|
| Scope | Core output = 0.80 V × 2,000 A = 1.6 kW; path loss = (2,000 A)² × 20 µΩ = 80 W. The 1,000 A step adds 20 mV resistive drop and 10 pH × (1,000 A/1 µs) = 10 mV inductive drop: 30 mV against the 40 mV allowance. Shelf input = 120/0.96 = 125 kW, with 5 kW conversion heat. The added 20 kW for 10 ms needs 200 J. The ideal requirement C ≥ 2×200/(50²−46²) F lies between 1.0 and 1.1 F: 1.0 F supplies 192 J and fails, while 1.1 F supplies about 210 J and clears this ideal screen. At 95% efficiency shelf input is about 126 kW and fails; 96% is the exact input-power threshold. Capacitance does not reduce steady input energy. |
| As of | 2026-09 |
| Source | Texas Instruments, power-management fundamentals — method reference; guide-authored hypothetical scenario September 8, 2026. No supplier quote or test measurement. |
| Derivation | Core output = 0.80 V × 2,000 A = 1.6 kW; path loss = (2,000 A)² × 20 µΩ = 80 W. The 1,000 A step adds 20 mV resistive drop and 10 pH × (1,000 A/1 µs) = 10 mV inductive drop: 30 mV against the 40 mV allowance. Shelf input = 120/0.96 = 125 kW, with 5 kW conversion heat. The added 20 kW for 10 ms needs 200 J. The ideal requirement C ≥ 2×200/(50²−46²) F lies between 1.0 and 1.1 F: 1.0 F supplies 192 J and fails, while 1.1 F supplies about 210 J and clears this ideal screen. At 95% efficiency shelf input is about 126 kW and fails; 96% is the exact input-power threshold. Capacitance does not reduce steady input energy. |
| Review | checking…review by 2027-03-08 · standard cadence |
| Recorded changes | last 2026-09-16 |
| Claim id | guide2-t29-7-12-result |
Where the guide uses it
← Full numbers register — every date-stamped figure in the guide, with revision history.