Approximate efficiency of a chopper (DC–DC converter) What is a typical overall efficiency figure for a practical chopper operating under normal conditions?

Introduction / Context:
DC–DC choppers use high-frequency switching to minimize dissipation and achieve high efficiency. Understanding realistic efficiency helps with thermal design and power budgeting for drives and power supplies.

Given Data / Assumptions:

• Modern switching devices with low conduction and switching losses.
• Reasonable magnetics and minimal control losses.
• No extreme low-load or poorly designed cases.

Concept / Approach:

Losses arise from conduction (I^2R or Vce(sat)·I), switching (overlap and device capacitances), gate drive, magnetics, and ripple. With proper design, these are a small fraction of output power, yielding high efficiency well above 80% and often 90–95% for medium to high power converters.

Step-by-Step Solution:

Verification / Alternative check:

Datasheets and application notes routinely report efficiencies exceeding 85–95% under nominal load.

Why Other Options Are Wrong:

• 50%, 20%, 5% are characteristic of linear regulators or faulty designs, not switching choppers.

Common Pitfalls:

Ignoring cooling and layout; excessive switching frequency without need; operating deep in light-load where fixed overheads dominate can reduce efficiency but rarely to very low values.

Final Answer:

80% or more