janik
06c62e04f8
DC/AC resistance, power dissipation, and via/injection-area currents of copper zone fills. KiCad 10 IPC-API plugin (kicad-python/kipy): multi-layer via-coupled FDM solver, multi-part terminals via User.1/User.2 marker layers, pads as contacts, uniform-injection and equipotential contact models, per-foil skin effect, optional solder/copper buildup on mask openings. 54-case test suite incl. exact analytic references. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
149 lines
6.0 KiB
Python
149 lines
6.0 KiB
Python
"""Multi-layer / via solver tests. The 1-cell-wide strip cases are pure
|
|
series chains, so the discrete solution is exact and validates the via
|
|
barrel model, layer coupling, and flux integration to solver precision."""
|
|
import math
|
|
|
|
import numpy as np
|
|
import pytest
|
|
|
|
from fill_resistance import raster, solver
|
|
from fill_resistance.errors import ConnectivityError, ElectrodeError
|
|
from tests.util import NM, make_multilayer, sigma_s
|
|
|
|
|
|
def _solve(problem, h_mm, i_test=1.0):
|
|
stack = raster.rasterize_stack(problem, h_mm * NM)
|
|
e1, e2 = raster.electrode_masks(stack, problem)
|
|
return solver.run_solve(problem, stack, e1, e2, i_test,
|
|
contact_model="equipotential"), stack
|
|
|
|
|
|
STRIP = [(0, 0), (10, 0), (10, 1), (0, 1)] # 10 x 1 mm; h=1 -> 1 row
|
|
|
|
|
|
def _r_via(length_mm, drill_mm=0.3, plating_um=18.0, rho=1.68e-8):
|
|
area = math.pi * (drill_mm * 1e-3) * (plating_um * 1e-6)
|
|
return rho * (length_mm * 1e-3) / area
|
|
|
|
|
|
def test_two_identical_layers_parallel():
|
|
"""Both electrodes contact both layers, no vias needed: two identical
|
|
independent sheets in parallel -> exactly half the single-layer R."""
|
|
one = make_multilayer([[(STRIP, [])]], (0, 0, 1, 1), (9, 0, 10, 1))
|
|
two = make_multilayer([[(STRIP, [])], [(STRIP, [])]],
|
|
(0, 0, 1, 1), (9, 0, 10, 1))
|
|
r1, _ = _solve(one, 1.0)
|
|
r2, _ = _solve(two, 1.0)
|
|
assert r2.R_ohm == pytest.approx(r1.R_ohm / 2, rel=1e-9)
|
|
|
|
|
|
def test_via_chain_1d_exact():
|
|
"""e1 on L0 left end, e2 on L1 right end, one through-via at x=5.5:
|
|
R = faces_L0/sigma + R_via + faces_L1/sigma, exact."""
|
|
p = make_multilayer(
|
|
[[(STRIP, [])], [(STRIP, [])]],
|
|
rect1_mm=(0, 0, 1, 1), rect2_mm=(9, 0, 10, 1),
|
|
contact1="L0", contact2="L1",
|
|
vias_mm=[(5.5, 0.5)], gap_mm=1.0)
|
|
res, stack = _solve(p, 1.0)
|
|
# cells at x centers 0.5..9.5 -> cols 0..9 (plus margins); electrode
|
|
# cells: col of 0.5 (e1), col of 9.5 (e2); via cell: col of 5.5
|
|
sig = sigma_s()
|
|
faces_l0 = 5 # cols 0->5: faces between 0|1 .. 4|5
|
|
faces_l1 = 4 # cols 5->9
|
|
r_exact = (faces_l0 + faces_l1) / sig + _r_via(1.0)
|
|
assert res.R_ohm == pytest.approx(r_exact, rel=1e-9)
|
|
assert res.mismatch_rel < 1e-10
|
|
assert len(res.via_reports) == 1
|
|
# the single via carries the full test current
|
|
assert res.via_reports[0].current_a == pytest.approx(1.0, rel=1e-9)
|
|
assert res.via_reports[0].power_w == pytest.approx(_r_via(1.0), rel=1e-9)
|
|
|
|
|
|
def test_parallel_vias_halve_barrel_resistance():
|
|
base = dict(rect1_mm=(0, 0, 1, 1), rect2_mm=(9, 0, 10, 1),
|
|
contact1="L0", contact2="L1", gap_mm=1.0)
|
|
one = make_multilayer([[(STRIP, [])], [(STRIP, [])]],
|
|
vias_mm=[(5.5, 0.5)], **base)
|
|
two = make_multilayer([[(STRIP, [])], [(STRIP, [])]],
|
|
vias_mm=[(5.5, 0.5), (5.5, 0.5)], **base)
|
|
r_one, _ = _solve(one, 1.0)
|
|
r_two, _ = _solve(two, 1.0)
|
|
assert (r_one.R_ohm - r_two.R_ohm) == pytest.approx(_r_via(1.0) / 2,
|
|
rel=1e-9)
|
|
|
|
|
|
def test_antipad_bridging():
|
|
"""3 layers; the middle layer has an antipad hole at the via cell, so
|
|
the barrel bridges L0 -> L2 directly with DOUBLE the length."""
|
|
mid_with_hole = [(STRIP, [[(5, 0), (6, 0), (6, 1), (5, 1)]])]
|
|
p = make_multilayer(
|
|
[[(STRIP, [])], mid_with_hole, [(STRIP, [])]],
|
|
rect1_mm=(0, 0, 1, 1), rect2_mm=(9, 0, 10, 1),
|
|
contact1="L0", contact2="L2",
|
|
vias_mm=[(5.5, 0.5)], gap_mm=1.0)
|
|
res, _ = _solve(p, 1.0)
|
|
sig = sigma_s()
|
|
r_exact = (5 + 4) / sig + _r_via(2.0) # barrel length 2 mm
|
|
assert res.R_ohm == pytest.approx(r_exact, rel=1e-9)
|
|
|
|
|
|
def test_via_short_between_electrodes_raises():
|
|
"""Both electrodes over the SAME cell on different layers with a via
|
|
there = direct short, no free copper -> error."""
|
|
p = make_multilayer(
|
|
[[(STRIP, [])], [(STRIP, [])]],
|
|
rect1_mm=(5, 0, 6, 1), rect2_mm=(5, 0, 6, 1),
|
|
contact1="L0", contact2="L1",
|
|
vias_mm=[(5.5, 0.5)], gap_mm=1.0)
|
|
stack = raster.rasterize_stack(p, 1.0 * NM)
|
|
e1, e2 = raster.electrode_masks(stack, p)
|
|
with pytest.raises(ElectrodeError, match="directly connected"):
|
|
solver.run_solve(p, stack, e1, e2, 1.0,
|
|
contact_model="equipotential")
|
|
|
|
|
|
def test_layers_without_via_disconnected():
|
|
p = make_multilayer(
|
|
[[(STRIP, [])], [(STRIP, [])]],
|
|
rect1_mm=(0, 0, 1, 1), rect2_mm=(9, 0, 10, 1),
|
|
contact1="L0", contact2="L1", gap_mm=1.0) # no vias
|
|
stack = raster.rasterize_stack(p, 1.0 * NM)
|
|
e1, e2 = raster.electrode_masks(stack, p)
|
|
with pytest.raises(ConnectivityError, match="not connected"):
|
|
solver.run_solve(p, stack, e1, e2, 1.0,
|
|
contact_model="equipotential")
|
|
|
|
|
|
def test_power_split_layers_and_vias():
|
|
"""Power accounting: layer + via powers sum to I^2 R."""
|
|
p = make_multilayer(
|
|
[[(STRIP, [])], [(STRIP, [])]],
|
|
rect1_mm=(0, 0, 1, 1), rect2_mm=(9, 0, 10, 1),
|
|
contact1="L0", contact2="L1",
|
|
vias_mm=[(5.5, 0.5)], gap_mm=1.0)
|
|
res, _ = _solve(p, 1.0, i_test=10.0)
|
|
assert res.power_balance_rel < 1e-9
|
|
assert res.P_vias == pytest.approx(100 * _r_via(1.0), rel=1e-9)
|
|
sig = sigma_s()
|
|
assert res.P_layers[0] == pytest.approx(100 * 5 / sig, rel=1e-9)
|
|
assert res.P_layers[1] == pytest.approx(100 * 4 / sig, rel=1e-9)
|
|
|
|
|
|
def test_pad_polygon_electrode():
|
|
"""A polygon-shaped electrode (pad) restricted to one layer."""
|
|
from fill_resistance.geometry import Electrode, Polygon
|
|
from tests.util import rect_mm, ring_mm
|
|
p = make_multilayer([[(STRIP, [])]], (0, 0, 1, 1), (9, 0, 10, 1))
|
|
# replace terminal 1 with a small polygon pad covering the same cell
|
|
p.electrodes1 = [Electrode(
|
|
rect=rect_mm((0.2, 0.2, 0.8, 0.8)),
|
|
contact="all",
|
|
polygons=[Polygon(outline=ring_mm(
|
|
[(0.2, 0.2), (0.8, 0.2), (0.8, 0.8), (0.2, 0.8)]))],
|
|
label="pad TP1.1",
|
|
)]
|
|
res, _ = _solve(p, 1.0)
|
|
sig = sigma_s()
|
|
assert res.R_ohm == pytest.approx(9 / sig, rel=1e-9) # cols 0..9
|