Light load stability circuitry for LDO regulator
US9069368B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 19, 2013 |
| Grant date | Jun 30, 2015 |
| Priority date | — |
| Expiry date | Mar 6, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F1/575
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A linear regulator contains an additional AC-coupled feedback loop between the output of the error amplifier and the base of the pass transistor that increases the frequency of the pole at the output of the error amplifier at light load currents to at least partially offset the decreased frequency of the output pole at the lighter load currents. Thus, a desired phase margin is preserved. The AC-coupled feedback loop includes a bipolar feedback transistor connected in parallel with the pass transistor. A resistor is connected to the emitter of the feedback transistor to reduce the relative gain of the feedback transistor above light load currents. A feedback capacitor Cfb is connected between the collector of the feedback transistor and the output of the error amplifier. The negative AC feedback increases the pole frequency at the output of the error amplifier and the base of the pass transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.