IC voltage regulator protection behavior: When an integrated-circuit voltage regulator experiences an overload condition, what is its typical protective response?

Introduction / Context:
Modern IC regulators incorporate protection features such as current limiting, foldback limiting, and thermal shutdown to survive overloads and short circuits. Understanding these responses is important when diagnosing why a supply output suddenly drops or cycles under fault conditions.

Given Data / Assumptions:

• Linear or switching IC regulator under overload/short-circuit.
• Internal protection mechanisms are active.
• Goal: identify the typical immediate response.

Concept / Approach:
Under severe overloads, many regulators first limit current; if power dissipation drives the die temperature high, thermal shutdown engages, turning the pass element off until the die cools. This behavior appears externally as a “shutdown” or hiccup-mode cycling rather than increasing output. Therefore, the safe, intended reaction to protect both the IC and the load is to shut down (or limit so aggressively that output effectively turns off) until conditions are safe again.

Step-by-Step Solution:
Fault causes output current to exceed limit → current limit engages.Junction temperature rises → thermal shutdown may trip.Regulator ceases conduction (off state) until temperature falls.Some designs then auto-restart, repeating if the fault persists.

Verification / Alternative check:
Datasheets for common regulators (e.g., 78xx linear, many buck controllers) specify current limit and thermal shutdown thresholds. Lab observation shows the output collapsing to near 0 V during persistent overloads.

Why Other Options Are Wrong:
Compensate for heat: vague and not the protective action; the IC does not “compensate” by raising voltage.Provide more voltage: would worsen the overload.Sample and adjust: describes normal regulation, not overload protection.

Common Pitfalls:
Assuming a steady output under short-circuit; instead, expect current limiting and thermal cycling or hiccup shutdown depending on the design.

Final Answer:
shut down