PCB Current Carrying Capacity

PCB Current Carrying Capacity  (PCB 전류용량)

0.5oz & 1oz 외부층 전류 용량 비교 표 (10°C 상승 허용)

전류 (A)0.5oz 필요한 최소 폭 (mil / mm)1oz 필요한 최소 폭 (mil / mm)비고 (0.5oz vs 1oz)

전류 (A)	0.5oz	1oz
0.5A	≈ 10–12 mil / 0.25–0.30 mm	≈ 5–7 mil / 0.13–0.18 mm	0.5oz는 거의 2배 폭 필요
1A	≈ 20–25 mil / 0.50–0.64 mm	≈ 10–12 mil / 0.25–0.30 mm	표준 신호/저전력 전원
1.5A	≈ 35–45 mil / 0.89–1.14 mm	≈ 18–22 mil / 0.46–0.56 mm
2A	≈ 55–70 mil / 1.4–1.8 mm	≈ 28–35 mil / 0.71–0.89 mm	소형 모터, USB 등
3A	≈ 100–130 mil / 2.5–3.3 mm	≈ 50–65 mil / 1.27–1.65 mm
5A	≈ 180–250 mil / 4.6–6.4 mm	≈ 90–120 mil / 2.3–3.0 mm	LED 스트립, 중형 전원
8A	≈ 350–450 mil / 8.9–11.4 mm	≈ 180–230 mil / 4.6–5.8 mm	(실제론 폭이 너무 커서 2oz 이상 추천)
10A	≈ 500–700 mil / 12.7–17.8 mm	≈ 250–350 mil / 6.4–8.9 mm	(0.5oz로는 거의 불가능, 폭 과다)

• 2oz (70μm) 구리면 위 폭의 약 60~65% 정도로 줄일 수 있습니다. (거의 √2 배 가까이 전류 용량 ↑)

 

0.5oz (17.5μm) 외부층 – 온도 상승별 최대 전류 (A) vs 필요한 최소 폭

필요한 최소 폭	1 0°C	2 0°C	3 0°C	4 0°C	5 0°C	비    고
5 mil (0.13 mm)	0.35 A	0.5 A	0.6 A	0.7 A	0.8 A	아주 저전력
10 mil (0.25 mm)	0.6 A	0.8 A	1.0 A	1.1 A	1.2 A	신호/저전력
15 mil (0.38 mm)	0.8 A	1.1 A	1.3 A	1.5 A	1.7 A
20 mil (0.51 mm)	1.0 A	1.4 A	1.7 A	1.9 A	2.1 A	1oz의 10mil 수준
30 mil (0.76 mm)	1.4 A	1.9 A	2.3 A	2.6 A	2.9 A
50 mil (1.27 mm)	2.0 A	2.8 A	3.4 A	3.9 A	4.3 A	중저전력
80 mil (2.03 mm)	2.9 A	4.0 A	4.8 A	5.5 A	6.1 A
100 mil (2.54 mm)	3.4 A	4.7 A	5.7 A	6.5 A	7.2 A
150 mil (3.81 mm)	4.6 A	6.3 A	7.6 A	8.7 A	9.6 A
200 mil (5.08 mm)	5.6 A	7.7 A	9.3 A	10.6 A	11.7 A	0.5oz 한계 근처

 

1oz (35μm) 외부층 – 온도 상승별 최대 전류 (A) vs 필요한 최소 폭

필요한 최소 폭	10°C	20°C	30°C	40°C	50°C	비고
5 mil (0.13 mm)	0.5 A	0.7 A	0.9 A	1.0 A	1.1 A	신호선 수준
10 mil (0.25 mm)	1.0 A	1.4 A	1.7 A	1.9 A	2.1 A	기본 전원
15 mil (0.38 mm)	1.4 A	1.9 A	2.3 A	2.6 A	2.9 A
20 mil (0.51 mm)	1.7 A	2.4 A	2.9 A	3.3 A	3.6 A	USB/모터 소형
30 mil (0.76 mm)	2.4 A	3.3 A	4.0 A	4.6 A	5.0 A
50 mil (1.27 mm)	3.5 A	4.9 A	5.9 A	6.7 A	7.4 A	LED/중형 전원
80 mil (2.03 mm)	5.0 A	6.9 A	8.3 A	9.5 A	10.5 A
100 mil (2.54 mm)	5.8 A	8.0 A	9.7 A	11.0 A	12.2 A
150 mil (3.81 mm)	7.8 A	10.8 A	13.0 A	14.8 A	16.4 A	고전류 시작
200 mil (5.08 mm)	9.5 A	13.1 A	15.8 A	18.0 A	19.9 A

 

실무 간단 Rule of Thumb (외부층 기준)

• 1oz: 10°C → 1mm 폭당 ≈ 1.0~1.2 A / 20°C → ≈1.4~1.6 A / 30°C → ≈1.7~2.0 A
• 0.5oz: 10°C → 1mm 폭당 ≈ 0.6~0.7 A (1oz의 약 60%)
• 온도 상승이 2배 되면 전류 용량은 약 √2 ≈ 1.4배 증가 (공식상 ΔT^0.44 영향)

더 정확한 값은 IPC-2152 기반 계산기(Sierra Circuits, Saturn PCB Toolkit 등)를 쓰는 게 좋고,

실제로는 주변 copper plane, 공기 흐름, 기판 두께 등으로 ±20~30% 차이 날 수 있어요.

 

 

 

Technical Report: PCB Trace Design & Current Carrying Capacity

Date: March 19, 2026

Project: XXXX

Document Ref: PCB-TR-2026-001

1. Executive Summary

This report verifies the safety and thermal stability of the PCB trace design for the XXXX PCB (Rev.A0). The analysis focuses on high-current paths, specifically the Heater (XXXkW) and Peltier (XXX) drive lines, to ensure they comply with international safety standards regarding temperature rise and current carrying capacity.

2. PCB Specification

• Substrate Material: FR-4
• Copper Weight: 0.5 oz (18µm) per layer
• Layer Count: 2 Layers (Top & Bottom)
• Routing Strategy: Parallel dual-layer routing for high-current paths

3. Current Carrying Capacity Analysis

The trace widths have been calculated based on IPC-2221A standards, targeting a maximum temperature rise ($\Delta T$) of under 30°C at peak load.

Trace Section	Peak Current	Copper Weight	Min. Trace Width (Per Layer)	Effective Total Width	Expected Temp Rise
xxx	XXX A	0.5 oz	4.44 mm	8.88 mm	< 30 °C
xxx	XXX A	0.5 oz	2.80 mm	5.60 mm	< 20 °C
Main Logic	XXX A	0.5 oz	0.50 mm	0.50 mm	Negligible

4. Design Justification & Safety Measures

• Dual-Layer Parallel Routing: To compensate for the 0.5 oz copper thickness, all high-current paths are routed identically on both Top and Bottom layers. This doubles the effective cross-sectional area, significantly reducing DC resistance and heat generation.
• Localized Bottleneck Management: The minimum width of 4.44mm is a localized constraint near the X-Cap  connection. This segment is immediately adjacent to wider copper planes (up to 12mm), which act as a heat sink to rapidly dissipate thermal energy.
• Thermal Margin: Even at a continuous XXXXkW load (XXXA), the calculated temperature rise remains well within the operational limits of the FR-4 substrate and surrounding components.

5. Conclusion

The current PCB layout for the AC Filter and Peltier drive sections is technically sound and meets the safety requirements for current carrying capacity. The design ensures that the temperature rise remains under 30°C during peak operation, maintaining long-term reliability.

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References:

• IPC-2221A: Generic Standard on Printed Board Design, Section 6.2.
• Thermal Analysis Data based on IPC-2152 Standard for Trace Design.

Prepared by:

[Your Name]

Firmware Programmer & Hardware Developer