1 / 8

Linear Regulator Fundamentals

Linear Regulator Fundamentals. 2.2 NPN. Linear-Regulator Operation. Voltage feedback samples the output R1 and R2 may be internal or external Feedback controls pass transistor’s current to the load. V. V. IN. OUT. PASS TRANSISTOR. R1. ERROR. C. AMP. C. IN. R. OUT. LOAD. R2. V.

constance-downs
Download Presentation

Linear Regulator Fundamentals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Linear Regulator Fundamentals 2.2 NPN

  2. Linear-Regulator Operation • Voltage feedback samples the outputR1 and R2 may be internal or external • Feedback controls pass transistor’s current to the load V V IN OUT PASS TRANSISTOR R1 ERROR C AMP C IN R OUT LOAD R2 V REF

  3. NPN "Quasi-LDO" Voltage Regulator • The NPN-Quasi-LDO has the following Characteristics: • Requires the input voltage to be at least 0.9V to 1.5V higher than the output voltage • Has higher Ground pin current than the NPN-Darlington, but less than the PNP-LDO Voltage Regulators • Requires an output capacitor, but, generally, has no specific ESR requirement like the PNP-LDO

  4. Losses in the NPN "Quasi-LDO" Simple Model of Losses in the NPN "Quasi-LDO"

  5. Driving the NPN "Quasi-LDO" Pass Element

  6. The drive current for a load current requirement of 5mA Drive Current vs. Low/High Load Current Increasing the load current requirement to 500mA

  7. Summary • The NPN-Quasi-LDO has the following Characteristics: • Requires the input voltage to be at least 0.9V to 1.5V higher than the output voltage • Has higher Ground pin current than the NPN-Darlington, but less than the PNP-LDO Voltage Regulators • Requires an output capacitor, but, generally, has no specific ESR requirement like the PNP-LDO

  8. Thank you!

More Related