<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Buck vs Boost Converter Power Stages</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    }
    body {
      background-color: #f8f9fa;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 12px 14px;
      user-select: none;
      -webkit-user-select: none;
      min-height: 100%;
    }
    .controls {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 580px;
      gap: 10px;
      margin-bottom: 12px;
    }
    .toggle-group {
      display: flex;
      background: #e2e8f0;
      border-radius: 8px;
      padding: 3px;
    }
    .toggle-btn {
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      border: none;
      background: transparent;
      color: #64748b;
      cursor: pointer;
      border-radius: 6px;
      transition: background-color 0.2s ease, color 0.2s ease;
    }
    .toggle-btn.active {
      background: #ffffff;
      color: #1e2945;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12);
    }
    .slider-container {
      display: flex;
      align-items: center;
      gap: 10px;
      flex-grow: 1;
      justify-content: flex-end;
    }
    .slider-label {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      min-width: 68px;
      text-align: right;
    }
    input[type="range"] {
      -webkit-appearance: none;
      appearance: none;
      width: 120px;
      height: 6px;
      background: #cbd5e1;
      border-radius: 3px;
      outline: none;
    }
    input[type="range"]::-webkit-slider-thumb {
      -webkit-appearance: none;
      appearance: none;
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: #22b7ff;
      cursor: pointer;
      box-shadow: 0 1px 3px rgba(0,0,0,0.25);
    }
    input[type="range"]::-moz-range-thumb {
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: #22b7ff;
      cursor: pointer;
      border: none;
    }
    .diagram-area {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      align-items: center;
      background: transparent;
    }
    svg {
      width: 100%;
      height: auto;
      overflow: visible;
    }
    .calc-banner {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
      align-items: center;
      gap: 8px;
      margin-top: 10px;
      font-size: 14px;
      font-weight: 600;
      background: transparent;
    }
    .math-highlight {
      color: #0284c7;
      font-size: 15px;
      font-weight: 700;
    }
    .val-pill {
      background: #e2e8f0;
      padding: 5px 12px;
      border-radius: 6px;
      color: #1e2945;
      font-size: 14px;
    }

    @media (max-width: 480px) {
      body {
        padding: 8px;
      }
      .controls {
        justify-content: center;
      }
      .toggle-group {
        width: 100%;
      }
      .toggle-btn {
        flex: 1;
        text-align: center;
        padding: 6px 8px;
        font-size: 12px;
      }
      .slider-container {
        width: 100%;
        justify-content: space-between;
      }
      input[type="range"] {
        flex-grow: 1;
      }
      .calc-banner {
        flex-direction: column;
        align-items: flex-start;
        gap: 6px;
      }
      .val-pill {
        align-self: stretch;
        text-align: center;
      }
    }
  </style>
</head>
<body>

  <div class="controls">
    <div class="toggle-group">
      <button id="buckBtn" class="toggle-btn active" onclick="setMode('buck')">Buck (Step-Down)</button>
      <button id="boostBtn" class="toggle-btn" onclick="setMode('boost')">Boost (Step-Up)</button>
    </div>
    <div class="slider-container">
      <span class="slider-label" id="dutyLabel">D = 50%</span>
      <input type="range" id="dutySlider" min="10" max="90" value="50" oninput="updateDuty(this.value)">
    </div>
  </div>

  <div class="diagram-area">
    <svg viewBox="0 0 580 215">
      
      <g stroke="#94a3b8" stroke-width="2.5" fill="none" stroke-linecap="round" stroke-linejoin="round">
        
        <path d="M 35 50 L 80 50" />
        <path d="M 35 160 L 490 160" />
        
        
        <g id="buckCircuit">
          
          <path d="M 135 50 L 195 50" />
          
          <path d="M 195 50 L 195 85" />
          <path d="M 195 125 L 195 160" />
          
          <path d="M 195 50 L 240 50" />
          <path d="M 320 50 L 410 50" />
        </g>

        
        <g id="boostCircuit" style="display: none;">
          
          <path d="M 80 50 L 125 50" />
          <path d="M 205 50 L 255 50" />
          
          <path d="M 255 50 L 255 80" />
          <path d="M 255 130 L 255 160" />
          
          <path d="M 255 50 L 310 50" />
          <path d="M 350 50 L 410 50" />
        </g>

        
        <path d="M 410 50 L 490 50" />
        
        <path d="M 410 50 L 410 90" />
        <path d="M 410 120 L 410 160" />
        
        <path d="M 490 50 L 490 85" />
        <path d="M 490 125 L 490 160" />
      </g>

      
      <circle cx="35" cy="50" r="4.5" fill="#1e2945" />
      <circle cx="35" cy="160" r="4.5" fill="#1e2945" />
      <text x="35" y="102" fill="#1e2945" font-size="14" font-weight="700" text-anchor="middle">V_in</text>
      <text x="35" y="120" fill="#64748b" font-size="12" font-weight="600" text-anchor="middle">12.0 V</text>

      
      
      <g id="inductor" transform="translate(235, 50)">
        <path d="M 0 0 C 10 -20, 18 -20, 22 0 C 32 -20, 40 -20, 44 0 C 54 -20, 62 -20, 66 0 C 76 -20, 84 -20, 88 0" 
              fill="none" stroke="#0284c7" stroke-width="3.5" stroke-linecap="round"/>
        <text x="44" y="-14" fill="#1e2945" font-size="14" font-weight="700" text-anchor="middle">L</text>
      </g>

      
      <g id="switchComp" transform="translate(108, 50)">
        <rect x="-24" y="-18" width="48" height="36" rx="4" fill="#ffffff" stroke="#1e2945" stroke-width="2"/>
        
        <line id="swArm" x1="-14" y1="0" x2="14" y2="-12" stroke="#22b7ff" stroke-width="3" stroke-linecap="round" />
        <circle cx="-14" cy="0" r="3" fill="#1e2945" />
        <circle cx="14" cy="0" r="3" fill="#1e2945" />
        <text id="swLabel" x="0" y="-23" fill="#1e2945" font-size="13" font-weight="700" text-anchor="middle">SW (f_s)</text>
      </g>

      
      <g id="diodeComp" transform="translate(195, 105)">
        <polygon id="diodePoly" points="0,-10 -11,10 11,10" fill="#22b7ff" stroke="#0284c7" stroke-width="1.5" />
        <line id="diodeLine" x1="-12" y1="-10" x2="12" y2="-10" stroke="#1e2945" stroke-width="3" stroke-linecap="round" />
        <text id="diodeLabel" x="18" y="4" fill="#1e2945" font-size="14" font-weight="700">D</text>
      </g>

      
      <g transform="translate(410, 105)">
        <line x1="-16" y1="-15" x2="16" y2="-15" stroke="#1e2945" stroke-width="3" stroke-linecap="round"/>
        <line x1="-16" y1="15" x2="16" y2="15" stroke="#1e2945" stroke-width="3" stroke-linecap="round"/>
        <text x="24" y="5" fill="#1e2945" font-size="14" font-weight="700">C</text>
      </g>

      
      <g transform="translate(490, 105)">
        <rect x="-10" y="-20" width="20" height="40" fill="#ffffff" stroke="#1e2945" stroke-width="2"/>
        <text x="18" y="5" fill="#1e2945" font-size="14" font-weight="700">R_load</text>
      </g>

      
      <circle cx="490" cy="50" r="4.5" fill="#22b7ff" />
      <circle cx="490" cy="160" r="4.5" fill="#22b7ff" />
      <text x="490" y="32" fill="#0284c7" font-size="14" font-weight="700" text-anchor="middle">V_out</text>

      
      <g transform="translate(70, 192)">
        <text x="-40" y="11" fill="#475569" font-size="12" font-weight="700">PWM Gate:</text>
        
        <rect x="40" y="-3" width="120" height="18" fill="#e2e8f0" rx="3" />
        
        <rect id="pwmHigh" x="40" y="-3" width="60" height="18" fill="#22b7ff" rx="3" />
        <text id="pwmText" x="100" y="10" fill="#ffffff" font-size="11" font-weight="700" text-anchor="middle">D · T_s</text>
      </g>
    </svg>
  </div>

  
  <div class="calc-banner">
    <div>
      <span class="math-highlight" id="formulaText">V_out = D · V_in</span>
    </div>
    <div class="val-pill">
      <span>Output Voltage: </span>
      <strong id="voutVal" style="color: #0284c7;">6.0 V</strong>
    </div>
  </div>

  <script>
    const VIN = 12.0;
    let mode = 'buck';
    let duty = 0.50;

    function setMode(m) {
      mode = m;
      document.getElementById('buckBtn').classList.toggle('active', m === 'buck');
      document.getElementById('boostBtn').classList.toggle('active', m === 'boost');

      const buckCircuit = document.getElementById('buckCircuit');
      const boostCircuit = document.getElementById('boostCircuit');
      const ind = document.getElementById('inductor');
      const sw = document.getElementById('switchComp');
      const swLabel = document.getElementById('swLabel');
      const diode = document.getElementById('diodeComp');
      const diodePoly = document.getElementById('diodePoly');
      const diodeLine = document.getElementById('diodeLine');
      const diodeLabel = document.getElementById('diodeLabel');

      if (m === 'buck') {
        buckCircuit.style.display = 'inline';
        boostCircuit.style.display = 'none';

        // SW series top
        sw.setAttribute('transform', 'translate(108, 50)');
        swLabel.setAttribute('x', '0');
        swLabel.setAttribute('y', '-23');

        // Diode pointing UP (cathode bar at top node y=50, anode at GND y=160)
        diode.setAttribute('transform', 'translate(195, 105)');
        diodePoly.setAttribute('points', '0,-10 -11,10 11,10');
        diodeLine.setAttribute('x1', '-12');
        diodeLine.setAttribute('y1', '-10');
        diodeLine.setAttribute('x2', '12');
        diodeLine.setAttribute('y2', '-10');
        diodeLabel.setAttribute('x', '18');
        diodeLabel.setAttribute('y', '4');

        // Inductor in series after node
        ind.setAttribute('transform', 'translate(235, 50)');
      } else {
        buckCircuit.style.display = 'none';
        boostCircuit.style.display = 'inline';

        // Inductor series first
        ind.setAttribute('transform', 'translate(120, 50)');

        // SW shunt down to ground
        sw.setAttribute('transform', 'translate(255, 105)');
        swLabel.setAttribute('x', '-34');
        swLabel.setAttribute('y', '4');

        // Diode pointing RIGHT in series to output (cathode bar at right)
        diode.setAttribute('transform', 'translate(330, 50)');
        diodePoly.setAttribute('points', '10,0 -10,-11 -10,11');
        diodeLine.setAttribute('x1', '10');
        diodeLine.setAttribute('y1', '-12');
        diodeLine.setAttribute('x2', '10');
        diodeLine.setAttribute('y2', '12');
        diodeLabel.setAttribute('x', '-2');
        diodeLabel.setAttribute('y', '-16');
      }

      updateCalculations();
    }

    function updateDuty(val) {
      duty = val / 100;
      document.getElementById('dutyLabel').textContent = `D = ${val}%`;
      updateCalculations();
    }

    function updateCalculations() {
      const voutValEl = document.getElementById('voutVal');
      const formulaEl = document.getElementById('formulaText');
      const pwmHigh = document.getElementById('pwmHigh');
      const pwmText = document.getElementById('pwmText');

      // Update PWM graphical pulse width (120px max)
      const pulseWidth = Math.max(12, Math.round(120 * duty));
      pwmHigh.setAttribute('width', pulseWidth);
      pwmText.setAttribute('x', 40 + pulseWidth / 2);

      let vout = 0;
      if (mode === 'buck') {
        formulaEl.innerHTML = `V<sub>out</sub> = D · V<sub>in</sub> = ${duty.toFixed(2)} × ${VIN.toFixed(0)}V`;
        vout = duty * VIN;
      } else {
        formulaEl.innerHTML = `V<sub>out</sub> = V<sub>in</sub> / (1 − D) = ${VIN.toFixed(0)}V / ${(1 - duty).toFixed(2)}`;
        vout = VIN / (1.0 - duty);
      }

      voutValEl.textContent = `${vout.toFixed(1)} V`;
    }

    // Switch pulse animation
    let swClosed = false;
    setInterval(() => {
      swClosed = !swClosed;
      const swArm = document.getElementById('swArm');
      if (swClosed) {
        swArm.setAttribute('y2', '0');
        swArm.setAttribute('stroke', '#0284c7');
      } else {
        swArm.setAttribute('y2', '-12');
        swArm.setAttribute('stroke', '#22b7ff');
      }
    }, 800);

    // Initial setup
    setMode('buck');
    updateCalculations();
  </script>
</body>
</html>

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