Strømreguleringsdiodes

Strømreguleringsdiodes, or current-regulating diodes (CRDs), are two-terminal semiconductor devices designed to provide a nearly constant current over a wide range of supply voltages. They achieve this by incorporating a built-in current-limiting mechanism and a reference element, so the output current remains relatively stable as the load varies within the device’s compliance range.

Operating principle: When forward biased, the device tends to set its current by regulating the voltage across its junctions and using internal circuitry to limit current. Regulation holds over a specified input voltage range and is largely independent of load resistance, provided the load voltage does not exceed the device’s compliance voltage. Above that limit, regulation may deteriorate.

Current values and compliance: CRDs are available in several current ratings, typically from fractions of a milliampere up to several tens of milliamperes, depending on the model. The regulated current is specified by the device, and regulation is maintained until the supply voltage reaches the compliance limit, after which current behavior becomes less predictable.

Temperature effects: The regulated current is influenced by temperature, so the current may drift with ambient or device temperature. This makes CRDs less suitable for applications requiring high-precision current control across varying temperatures, though they remain useful where coarse regulation is acceptable.

Applications and limitations: CRDs offer simplicity and low part count, enabling constant-current operation without external resistors. They are used for small LED driving, transistor biasing, and calibration tasks. Limitations include limited precision, temperature drift, and a restricted range of currents and voltages.

Packaging and variants: CRDs come in common diode packages suitable for through-hole and surface-mount assemblies. Different models provide various current ratings and voltage limits, with some optimized for stability or compact size.