In advance of the upcoming “Ask the Experts” session on Planet Analog on Wednesday, April 23, at 1:00 p.m. EDT, Planet Analog brings you this series of brief daily “nuggets” to fuel your quest for a deeper understanding of this topic, and as a preparation for you to ask questions during our session next week. Here is the first nugget.
The Linear Regulator (Excerpts from a Texas Instruments Application note)
We see a tremendous need in today’s electronic design for battery powered equipment, especially in the past decade and with the advent of the Internet of Things (IoT). This quest has created unique requirements for a voltage regulator that, in many instances, cannot be met by industry standards like the LM340 or the LM317 (Bob Dobkin’s design still is used widely in so many designs around the world).
These regulators use an NPN Darlington pass transistor (Figure 1), and can be referred to in this document as NPN regulators . The demand for higher performance is being met by the newer lowdropout (LDO) regulators.
The NPN Darlington pass transistor with PNP driver used in an NPN regulator requires that at least 1.5V to 2.5V be maintained from input-to-output for the device to stay in regulation. This minimum voltage “headroom” (called the dropout voltage ) is:
How to sign on to the chat session
Stay tuned to Planet Analog daily for these nuggets. Please register on Planet Analog if you have not done so already and click on this link to enter our chat room. You can begin to ask questions immediately today in advance of the actual chat on Wednesday, April 23, at 1:00 p.m. EDT. Your questions will be answered during the chat for all to see.