IC-Hersteller Kinetic Technology

IC-Hersteller (95)

Kinetic Technology KTA1136 | Demoboard AN162

Using PoE PD DC-DC Controllers in the Non-Isolated Buck Configuration

Details

TopologieAbwärtswandler
Eingangsspannung38-48 V
Schaltfrequenz100-800 kHz
Ausgang 112 V / 1.1 A
IC-Revision04a

Beschreibung

Most PoE PD applications use an isolated converter topology, and the available controllers are designed for this configuration. However, they may also be used for non-isolated topologies. The 802.3af/at/bt PoE standards specify input to output isolation, but many low-cost applications comply using other techniques. If the PD system ground is constrained to a single point (the source Ethernet cable), and there are no other connectors and no access to non-isolated conductors, a non-isolated power supply complies with the standard.There are two configurations possible for the non-isolated Buck. The Buck topology may be configured with Vin(-) as the common input to output connection, or it may be configured with Vin(+) as the common input to output connection. The former is referred to as a low-side Buck, and the latter a high-side Buck; in reference to the location of the common rail. Each has its advantages and disadvantages. Both have the PD/DC-DC controller IC referenced to Vin(-), so either the FET driver output and current sense signal must be level shifted to or from the floating gate-source, or the feedback signal must be level-shifted to IC ground reference Vin(-). For simplification and clarity, VIN is defined as Vin(+) – Vin(-) and VOUT is defined as Vout(+) – Vout(-).A non-isolated topology reduces the cost and complexity of the power conversion function in a PD, so its appeal is obvious. However, there are some disadvantages to the Buck topology regardless of configuration which will be discussed later in this application note.

Eigenschaften

  • Compliant to IEEE® Std. 802.3af-2003
  • Supports Type 1 operation for IEEE® 802.3at2009 and IEEE® 802.3bt-2018
  • Integrated DC-DC Controller with robust 150V, 0.7Ω typ. supporting both isolated and nonisolated applications
  • Low RDS_ON Hot-Swap FET, 0.49Ω typ.
  • Adjustable switching frequency from 100kHz to 800kHz
  • Programmable DC-DC Current Limit
  • Integrated Surge Protection for 15kV/8kV System level ESD Compliance
  • Exceptional EMI performance -Integrated Short-Circuit Protection
  • Over temperature protection
  • RoHS & Pb Free 4x4 mm, 16 lead TQFN Package
  • Industrial temperature range (-40°C to +85°C)

Typische Anwendungen

  • security and web cameras, Voice over IP (VoIP) phones, Wireless LAN access points, Fiber-to-the-home (FTTH) terminals

Weiterführende Informationen

Artikeldaten

Artikel Nr. Daten­blatt Simu­lation Downloads ProduktserieL
(µH)
IR
(A)
ISAT
(A)
RDC max.
(mΩ)
fres
(MHz)
BauformVersion Muster
7447709470SPEC

Anstehende PCN

Aufgrund einer anstehenden PCN wird in Kürze eine Änderung am Bauteil durchgeführt. Anbei finden Sie die entsprechende PCN. Bei weiteren Fragen wenden Sie sich bitte an Ihren Vertriebsmitarbeiter.

8 Dateien WE-PD SMT-Speicherdrossel 47 3.8 4.5 60 6.5 1210 Standard
Artikel Nr. Daten­blatt Simu­lation
7447709470SPEC

Anstehende PCN

Aufgrund einer anstehenden PCN wird in Kürze eine Änderung am Bauteil durchgeführt. Anbei finden Sie die entsprechende PCN. Bei weiteren Fragen wenden Sie sich bitte an Ihren Vertriebsmitarbeiter.

Muster
Artikel Nr. Daten­blatt Simu­lation Downloads ProduktserieL
(µH)
IR
(A)
ISAT
(A)
RDC max.
(mΩ)
fres
(MHz)
BauformVersion Muster