Publication detail

How to Design Enhanced LDO by the Other Way

LONDÁK, P. MATĚJ, J. ROZSYPAL, P.

Original Title

How to Design Enhanced LDO by the Other Way

Type

lecture

Language

English

Original Abstract

New Intelligent systems require high efficient, fast response and excellently behaving power supply devices. Although Low Dropout Voltage Regulators (LDO) have been very known devices for many tens of years, getting new challenges of their operating applications require also a new approach in design. Low Dropout Voltage regulators belong to the linear systems. True LDO regulaters can achieve much lower Vin-Vout drop voltage than Vth (MOS) or Vbe (BJT). Linear regulators drive MOSFET or BJT power device at their outputs so that the whole circuit behaves like a variable resistor. In the history N type power transistors were preffered to P type due to their fundamental advantages. Nevertheless, P type LDOs are dominant nowadays. To design a real LDO with N type transistor there is neccessarry to use dual supply rails in the system. How to comprise advantages of a single supply rail with NMOS output topoogy? It is possible by implementing an inner charge pump system providing internal auxiliary bias itself. Nevertheless, as a switching circuit, a charge pump is not very common in precise linear systems.It can bring higher power consumption, higher noise, lower PSRR, cross-talks, undesirable interferences into main regulation loop which arfe crucial parameters. However, the whole enhanced LDO system with a charge pump can be set up to fulfill all analog demands for ultra-precision linear circuit. The article presents how to make it.

Keywords

LDO, Charge pump, Efficient linear system, Low Dropout Voltage Regulator, One time Programming Memory, OTP, Ultra Low Voltage, Enhanced Band Gap Reference, ultra low noise, high PSRR

Authors

LONDÁK, P.; MATĚJ, J.; ROZSYPAL, P.

Released

25. 10. 2019

Publisher

On Semiconductor

Location

Taiwan

URL

http://theconnection.onsemi.com/corprnd/LP/dst/sharetech/EngForum/ETF-2019/default.aspx

BibTex

@misc{BUT161427,
  author="Pavel {Londák} and Jan {Matěj} and Petr {Rozsypal}",
  title="How to Design Enhanced LDO by the Other Way",
  year="2019",
  publisher="On Semiconductor",
  address="Taiwan",
  url="http://theconnection.onsemi.com/corprnd/LP/dst/sharetech/EngForum/ETF-2019/default.aspx",
  note="lecture"
}