Adom Custom Electronic Load

@@ -0,0 +1,181 @@+{+  "formalAcceptance": false,+  "inputIdentity": {+    "algorithm": "sha256",+    "board": "54f1aab0a34622d1c3675c13f4aeb7a678b0cee8b5a4d3bfd7484b10edb8dcf6",+    "solverVersion": "0.6.2",+    "spec": "012ba0487f597f1fe46672c3811dbb4db8c4eb57d33f4da81090f1b7795af72d"+  },+  "peakJDefinition": {+    "displayPercentile": 0.995,+    "minimumCopperFraction": 0.25,+    "rounded": false,+    "statistic": "unclipped-cell-maximum"+  },+  "nets": [+    {+      "amps": 3.000220385674931,+      "copperMm2": 71.8,+      "iterations": 647,+      "jouleW": 0.014,+      "layers": [+        "F.Cu",+        "B.Cu"+      ],+      "net": "DUT_POS",+      "peakAt": [+        107.1,+        93.9+      ],+      "peakJ": 48.634830474853516,+      "peakLayer": "F.Cu",+      "platedPads": 1,+      "residual": 8.537579182423423e-08,+      "vias": 2+    },+    {+      "amps": 3.0000289156626505,+      "copperMm2": 159.2,+      "iterations": 733,+      "jouleW": 0.027,+      "layers": [+        "F.Cu",+        "B.Cu"+      ],+      "net": "LOAD_POS",+      "peakAt": [+        126.5,+        86.3+      ],+      "peakJ": 68.60289001464844,+      "peakLayer": "F.Cu",+      "platedPads": 1,+      "residual": 9.802374552737071e-08,+      "vias": 15+    },+    {+      "amps": 3.0,+      "copperMm2": 5211.5,+      "iterations": 7021,+      "jouleW": 0.053,+      "layers": [+        "F.Cu",+        "B.Cu"+      ],+      "net": "GND",+      "peakAt": [+        136.1,+        100.89999999999999+      ],+      "peakJ": 76.35523223876953,+      "peakLayer": "F.Cu",+      "platedPads": 14,+      "residual": 9.83067050263189e-08,+      "vias": 48+    },+    {+      "amps": 3.0,+      "copperMm2": 46.6,+      "iterations": 254,+      "jouleW": 0.026,+      "layers": [+        "F.Cu",+        "B.Cu"+      ],+      "net": "SHUNT_P",+      "peakAt": [+        127.1,+        83.3+      ],+      "peakJ": 60.97330093383789,+      "peakLayer": "B.Cu",+      "platedPads": 1,+      "residual": 9.920461353185108e-08,+      "vias": 7+    },+    {+      "amps": 3.0,+      "copperMm2": 19.7,+      "iterations": 147,+      "jouleW": 0.003,+      "layers": [+        "F.Cu",+        "B.Cu"+      ],+      "net": "DUT_FUSED",+      "peakAt": [+        109.1,+        91.9+      ],+      "peakJ": 45.40793228149414,+      "peakLayer": "F.Cu",+      "platedPads": 0,+      "residual": 7.208780991872171e-08,+      "vias": 2+    },+    {+      "amps": 0.3,+      "copperMm2": 66.6,+      "iterations": 756,+      "jouleW": 0.001,+      "layers": [+        "F.Cu",+        "B.Cu"+      ],+      "net": "5V_AUX",+      "peakAt": [+        152.1,+        90.1+      ],+      "peakJ": 18.182907104492188,+      "peakLayer": "F.Cu",+      "platedPads": 2,+      "residual": 8.34572086330967e-08,+      "vias": 7+    }+  ],+  "currentIssues": [+    {+      "at": [+        136.1,+        100.89999999999999+      ],+      "fix": "Widen the neck or add a parallel path on the other layer with vias; the density map shows where the current squeezes.",+      "kind": "current-neck",+      "layer": "F.Cu",+      "net": "GND",+      "reference": null,+      "severity": "medium",+      "what": "GND: 76 A/mm\u00b2 at its worst point on F.Cu (3 A through a neck about 1.12 mm wide at 35 \u00b5m; the threshold is 60 A/mm\u00b2)"+    },+    {+      "at": [+        126.5,+        86.3+      ],+      "fix": "Widen the neck or add a parallel path on the other layer with vias; the density map shows where the current squeezes.",+      "kind": "current-neck",+      "layer": "F.Cu",+      "net": "LOAD_POS",+      "reference": null,+      "severity": "medium",+      "what": "LOAD_POS: 69 A/mm\u00b2 at its worst point on F.Cu (3.0000289156626505 A through a neck about 1.25 mm wide at 35 \u00b5m; the threshold is 60 A/mm\u00b2)"+    },+    {+      "at": [+        127.1,+        83.3+      ],+      "fix": "Widen the neck or add a parallel path on the other layer with vias; the density map shows where the current squeezes.",+      "kind": "current-neck",+      "layer": "B.Cu",+      "net": "SHUNT_P",+      "reference": null,+      "severity": "medium",+      "what": "SHUNT_P: 61 A/mm\u00b2 at its worst point on B.Cu (3 A through a neck about 1.41 mm wide at 35 \u00b5m; the threshold is 60 A/mm\u00b2)"+    }+  ],+  "sourcePr": "https://wiki.adom.inc/adom/adom-fields/prs/7",+  "solverSha256": "0ab71adbbe0088c5d56d81f053703d0efb41d2b82f1d781686711f1e11829158",+  "correction": "Earlier 57.9 A/mm2 peak was display-clipped; earlier isolated current pass is invalid for maximum-density acceptance. Live current remained failed."+}

@@ -0,0 +1,125 @@+#!/usr/bin/env python3+"""Project-only Kelvin-return voltage diagnostic; nominal copper and ideal pad contacts."""+import hashlib,json,math+from pathlib import Path+import numpy as np+from sexp import parse,find,first+ROOT=Path(__file__).resolve().parents[1]+BOARD=ROOT/'aiflow/run/board-19.kicad_pcb'+SIGMA=58000.0 # S/mm at nominal reference temperature++def solve(edges,injections):+    nodes=sorted({n for a,b,r,meta in edges for n in [a,b]}); ids={n:i for i,n in enumerate(nodes)}+    matrix=np.zeros((len(nodes),len(nodes))); rhs=np.zeros(len(nodes))+    for a,b,r,meta in edges:+        if a==b:continue+        assert r>0+        i,j=ids[a],ids[b];g=1/r+        matrix[i,i]+=g;matrix[j,j]+=g;matrix[i,j]-=g;matrix[j,i]-=g+    for n,a in injections.items():rhs[ids[n]]+=a+    assert abs(sum(injections.values()))<1e-10+    adjacency={n:set() for n in nodes}+    for a,b,r,m in edges:adjacency[a].add(b);adjacency[b].add(a)+    reached=set();pending=[nodes[0]]+    while pending:+        n=pending.pop()+        if n in reached:continue+        reached.add(n);pending.extend(adjacency[n]-reached)+    if len(reached)!=len(nodes):+        print('DISCONNECTED', [n for n in nodes if n not in reached]);print('INJECTIONS',injections)+        raise ValueError(f'Disconnected resistor graph: {len(reached)} of {len(nodes)} nodes')+    v=np.zeros(len(nodes));v[1:]=np.linalg.solve(matrix[1:,1:],rhs[1:])+    residual=matrix@v-rhs+    assert np.max(np.abs(residual))<1e-8+    return [(v[ids[a]]-v[ids[b]])/r if a!=b else 0 for a,b,r,meta in edges],float(np.max(np.abs(residual))),{n:float(v[ids[n]]) for n in nodes}++# Analytic series and parallel checks prevent current-sharing/unit regressions.+assert np.allclose(np.abs(solve([('a','b',1,{}),('b','c',2,{})],{'a':3,'c':-3})[0]),[3,3])+assert np.allclose(np.abs(solve([('a','b',1,{}),('a','b',2,{})],{'a':3,'b':-3})[0]),[2,1])+b=parse(BOARD.read_text());netnames={str(n[1]):str(n[2]) for n in find(b,'net')}+def net(n):+    v=first(n,'net')[1];return netnames.get(str(v),str(v))+def xy(n,k):return tuple(float(x) for x in first(n,k)[1:3])+def node(layer,p):return (layer,round(p[0],6),round(p[1],6))+allresults=[]+for name in ['SHUNT_N_SENSE']:+    edges=[]; unions={}+    def root(n):+        while n in unions:n=unions[n]+        return n+    def union(a,c):+        a,c=root(a),root(c)+        if a!=c:unions[max(a,c)]=min(a,c)+    for s in find(b,'segment'):+        if net(s)!=name:continue+        a,c=xy(s,'start'),xy(s,'end');width=float(first(s,'width')[1]);layer=str(first(s,'layer')[1]);length=math.dist(a,c)+        edges.append((node(layer,a),node(layer,c),length/(SIGMA*width*.035),{'kind':'track','id':str(first(s,'uuid')[1]),'widthMm':width,'lengthMm':length,'layer':layer}))+    for v in find(b,'via'):+        if net(v)!=name:continue+        at=xy(v,'at');d=float(first(v,'drill')[1]);plating=.025+        area=math.pi*((d/2+plating)**2-(d/2)**2)+        edges.append((node('F.Cu',at),node('B.Cu',at),1.6/(SIGMA*area),{'kind':'via','id':str(first(v,'uuid')[1]),'barrelAreaMm2':area}))+    # Split centerlines at every existing same-layer endpoint before pad union.+    endpoints={n for a,c,r,m in edges for n in (a,c)}+    split=[]+    for a,c,r,m in edges:+        if m['kind']!='track':+            split.append((a,c,r,m));continue+        dx,dy=c[1]-a[1],c[2]-a[2];length2=dx*dx+dy*dy+        cuts={0.0:a,1.0:c}+        for n in endpoints:+            if n[0]!=a[0]:continue+            t=((n[1]-a[1])*dx+(n[2]-a[2])*dy)/length2+            if 1e-8<t<1-1e-8 and math.hypot(n[1]-a[1]-t*dx,n[2]-a[2]-t*dy)<1e-6:cuts[t]=n+        ordered=sorted(cuts.items())+        for (ta,na),(tb,nb) in zip(ordered,ordered[1:]):+            metadata=dict(m);metadata['lengthMm']*=tb-ta+            split.append((na,nb,r*(tb-ta),metadata))+    edges=split+    pads={}+    for f in find(b,'footprint'):+        ref=next((str(p[2]) for p in find(f,'property') if p[1]=='Reference'),'')+        at=first(f,'at');fx,fy=map(float,at[1:3]);angle=float(at[3]) if len(at)>3 else 0+        for p in find(f,'pad'):+            if not first(p,'net') or net(p)!=name:continue+            +            px,py=xy(p,'at');c=math.cos(math.radians(angle));sn=math.sin(math.radians(angle));cx,cy=fx+px*c+py*sn,fy-px*sn+py*c;size=xy(p,'size');padnum=str(p[1]);pads[(ref,padnum)]=(cx,cy)+            layers=['F.Cu','B.Cu'] if p[2]=='thru_hole' else [str(first(p,'layers')[1])]+            for layer in layers:+                center=node(layer,(cx,cy))+                # Ideal equipotential pad, using its actual rotated copper outline.+                padat=first(p,'at');pa=math.radians(float(padat[3]) if len(padat)>3 else angle)+                radius=float(first(p,'roundrect_rratio')[1])*min(size) if first(p,'roundrect_rratio') else 0+                def contains(n):+                    dx,dy=n[1]-cx,n[2]-cy+                    x=abs(dx*math.cos(pa)-dy*math.sin(pa));y=abs(dx*math.sin(pa)+dy*math.cos(pa))+                    if p[3]=='circle':return math.hypot(x,y)<=size[0]/2+1e-7+                    if p[3] not in ('rect','roundrect'):raise ValueError(f'Unsupported pad shape {p[3]}')+                    if x>size[0]/2+1e-7 or y>size[1]/2+1e-7:return False+                    return math.hypot(max(0,x-size[0]/2+radius),max(0,y-size[1]/2+radius))<=radius+1e-7+                for edge in edges:+                    for n in edge[:2]:+                        if n[0]==layer and contains(n):union(center,n)+            if p[2]=='thru_hole':+                drill=float(first(p,'drill')[1]);area=math.pi*((drill/2+.025)**2-(drill/2)**2)+                edges.append((node('F.Cu',(cx,cy)),node('B.Cu',(cx,cy)),1.6/(SIGMA*area),{'kind':'plated-pad','pin':ref+'.'+padnum,'barrelAreaMm2':area}))+    edges=[(root(a),root(c),r,m) for a,c,r,m in edges]+    for source_layer in (['F.Cu','B.Cu'] if name=='DUT_POS' else ['F.Cu']):+        branch_loads={('U2','4'):.002,('U3','2'):.0018,('U4','7'):.00042+24/830000,('U7','12'):.0016,('R10','2'):2.5/(33000+5600+1000),('R19','2'):2.5/(10000+3300),('R23','2'):2.5/(33000+1000),('R28','2'):2.5/(1000+10000)}+        points=[('F.Cu',pads[k],amps) for k,amps in branch_loads.items()]+        points.append(('F.Cu',pads[('RSH1','3')],-sum(branch_loads.values())))+        injection={}+        for layer,p,amps in points:injection[root(node(layer,p))]=injection.get(root(node(layer,p)),0)+amps+        currents,residual,volts=solve(edges,injection);rows=[]+        for e,current in zip(edges,currents):+            m=dict(e[3]);m['amps']=abs(float(current));m['resistanceOhm']=e[2]+            if m['kind']=='track':+                area=m['widthMm']*.035*1550.0031+                m['ipc2221RiseC']=(m['amps']/(.048*area**.725))**(1/.44)+            rows.append(m)+        reference_v=volts[root(node('F.Cu',pads[('RSH1','3')]))]+        potentials={f'{ref}.{pin}':(volts[root(node('F.Cu',pos))]-reference_v) for (ref,pin),pos in pads.items()}+        allresults.append({'terminalVoltsRelativeToRshuntSense':potentials,'analogBiasAmps':sum(branch_loads.values()),'net':name,'sourceLayer':source_layer,'kclMaxResidualA':residual,'conductors':rows,'peakTrackRiseC':max(r.get('ipc2221RiseC',0) for r in rows)})+report={'formalAcceptance':False,'kind':'kelvin-return-voltage-diagnostic','boardSha256':hashlib.sha256(BOARD.read_bytes()).hexdigest(),'cases':allresults,'limits':['Tracks modeled as uniform straight resistors; no filled polygon current distribution','Pads treated equipotential; pad necks/contact spreading and track-overlap junctions not qualified','35 um copper, 25 um barrel plating, 1.6 mm barrels assumed, not measured','Maximum quiescent currents under their datasheet conditions plus divider currents; transient and comparator output sink currents excluded','No thermal coupling, conductivity-temperature feedback or pulse heating','This diagnostic does not override AIFlow or Fields gates']}+(ROOT/'design/step12-kelvin-return-summary.json').write_text(json.dumps(report,indent=2)+'\n')+for r in allresults:print(r['net'],r['analogBiasAmps'],'A',r['terminalVoltsRelativeToRshuntSense'])