How a Boost Converter Increases 20V to 40V Without Breaking Energy Conservation
Ever wondered how a circuit can convert 20V into 40V without violating the law of energy conservation? The answer lies in a powerful electronic device called a Boost Converter.
What is a Boost Converter?
A boost converter is a type of DC-DC converter that increases (boosts) input voltage to a higher output voltage using smart energy transfer techniques.
Main Components:
- Inductor
- Switch (Transistor)
- Diode
- Capacitor
It does NOT create energy. Instead, it converts low voltage & high current into high voltage & low current.
Step-by-Step Working of a Boost Converter
Step 1: Switch ON (Energy Storage Phase)
- The transistor closes.
- Current flows through the inductor.
- The inductor stores energy in its magnetic field.
Energy stored in inductor:
E = ½ × L × I²
During this phase, the diode blocks current to the output.
Step 2: Switch OFF (Energy Transfer Phase)
- The transistor opens.
- The inductor resists sudden current drop.
- Its voltage reverses polarity.
- The inductor voltage adds to the source voltage.
Output Voltage Formula:
Vout = Vsource + Vinductor
If source = 20V and inductor adds 20V → Output becomes 40V.
How Energy Conservation Still Holds
The key formula:
P = V × I
Power input is approximately equal to power output (ignoring small losses).
Example:
Input:
- Voltage = 20V
- Current = 4A
Pin = 20 × 4 = 80W
Output:
- Voltage = 40V
- Current = 2A
Pout = 40 × 2 = 80W
✔ Voltage Doubled
✔ Current Halved
✔ Power Same
✔ Energy Conserved
Important Concept
When voltage increases, current decreases proportionally.
Energy is temporarily stored in the inductor and then released at a higher voltage. No energy is magically created.
Conclusion
A boost converter can step up 20V to 40V by:
- Storing energy in an inductor
- Releasing it at higher voltage
- Reducing output current
The law of energy conservation is never violated.
Understanding this concept is fundamental in power electronics, DC-DC converters, and electrical engineering.