| Resistor |
Inexpensive Only one, large component |
It cannot control current accurately.Current varies to some extent with supply voltage.High power dissipation in the resistor; must be sized accordingly. |
2.8W |
| Active Linear Control |
Linear control-loop circuitry accurately controls the LED current.Allows dimming through current control.Allows dimming through control of amplitude or low-frequency PWM.Allows automatic temperature compensation of LED characteristics. |
Is more expensive than the simple resistive current limiterFor the same supply voltage, dissipates about the same power as a resistor limiter.May require mechanical heatsinking of the active pass device. |
2.8W |
| Switching Regulator Control |
Control loop regulates LED current precisely.Allows dimming by amplitude control or low-frequency PWM.Allows automatic temperature compensation of LED characteristics.Allows efficient operation over a wide input-voltage range.Does not usually have mechanical heatsinking, which saves cost and complexity.Powers LEDs in applications for which higher input voltage and higher LED currents may cause prohibitive losses with other methods. |
Has higher cost than the resistor and linear-control methods.Careful design is necessary to allay EMI considerations.Active circuitry may require more area, but the other methods may require more hardware and physical space for cooling. |
<0.8W |
