Boosting the CLD.pdf

Boosting the CLDBoosting the Current Limit of Current Limiting Diodes
As seen in the October issue of ECN
by Sze Chin, Central Semiconductor Corp.

Introduction
The current limiting diode (CLD) or current regulating diode (CRD), despite its simplicity and distinct advantage over a conventional transistorized current source, has limited use. One reason is that presently available CLD’s can provide current regulation only up to 15mA maximum, and in terms of power, only 1 watt maximum. Hence, the usefulness of the CLDs is limited to low power applications such as telephone line circuit modules, handheld devices and single IC chips or small areas of a PC board. However, the bulk of electronic applications involve current levels much higher than 15 mA and the same may be said of the power levels. Conventionall