Home >  Applications >  Power over Ethernet

Power over Ethernet Solutions

 

Since the first PoE product, an IP phone, was introduced in 2000, the number and variety of PoE applications have increased dramatically.  As the concept gained acceptance (standardized) and as available power increased, the number and variety of applications supported by PoE exploded to include devices such as IP video phones, wireless LAN & WiMAX access points (WAP), IP cameras, thin-client and notebook computers, and LED lighting, to name a few. 

 

PoE hardware consists of an Ethernet link combined with DC power source, defined as the Power Sourcing Equipment or PSE, and a Powered Device or PD which is the application appliance.  One characteristic of PoE is the PD/PSE interface and power supply are essentially application blind.  The only variables of concern are how many voltage rails, the voltage and rating of each rail, and the total power requirement.  The PoE standard (currently IEEE802.3at) does specify the output voltage(s) be isolated from the input, but compliance is not universal.  The reasons behind the requirement are product safety concerns (access to hazardous voltages) and EMC compliance issues that may arise from ground loops.  However, some applications, such as entry level IP phones, circumvent the requirement by careful enclosure design which restricts access to signals, voltages, and conductors.  There are, consequently, both isolated and non-isolated power solutions for PoE.  The non-isolated designs are addressed with buck converters and the isolated designs are dominated by the flyback topology.  Higher efficiency topologies may be considered if the application approaches or just exceeds the input power limits of PoE. 

 

The majority of PoE power solutions are flyback converter based.  A single isolated output is created, and if multiple voltage rails are required, the remaining rails are generally created with non-isolated buck or boost converters and use the isolated output as an input source.  This reduces the number of transformer windings required and results in a smaller, lower cost, standard transformer.  The isolated output is typically 3.3, 5, or 12V with the exception of LED lighting applications which are likely to be 18, 24, 36, or even 48V. 

 

Power utilization is a major consideration for PoE applications.  Not only is the input power limited by the PoE standard, but thermal management can be a challenge.  Most PDs reside in an unvented enclosure, particularly for outdoor applications.  As most applications are self-contained and do not power peripheral devices, the input power ends up dissipated within the enclosure.  While there is little that can be done to reduce the load power since most applications will utilize all available power to maximize functionality, the conversion efficiency of the power supply plays a key role in the power budget.  Maximizing efficiency may either reduce the thermal load within the PD or it may free up additional power for the load. 

 

Kinetic Technologies offers a broad portfolio of product solutions which integrate the PD physical interface and DC/DC controller functions into a single package.  Supporting solutions from a few watts up to the maximum allowed, Kinetic Technologies provides high efficiency power solutions for nearly every PoE PD application.

 

+ Power Interface  

 

PoE Applications often need internal voltage rail on/off control to reduce standby or shutdown state power consumption or to enable/disable specific function circuits while the device is operating.

 

  •  Integrated load switches provide simplified microcontroller I/O controlled power switching to eliminate the need for bias and level shift            circuits associated with discrete MOSFET switches.
  •  Load switches also provide slew rate limited turn on and shutdown mode reverse current blocking.

 

Part NumberDescriptionPackagePackage Alt.Package Alt.1
KTS1601 SRC P-Ch Load Switch with Reverse Blocking WLCSP-4 1.0 x 1.0mm    
KTS1601-1 SRC P-Ch Load Switch with Reverse Blocking and Output Discharge WLCSP-4 1.0 x 1.0mm    
KTS1605 SRC P-Ch Load Switch with Reverse Blocking WLCSP-6 1.0 x 1.5mm    
KTS1605-1 SRC P-Ch Load Switch with Reverse Blocking and Output Discharge WLCSP-6 1.0 x 1.5mm    

+ RGB LED Drivers  

 

PoE applications often need multicolor RGB LEDs for function indicator lamps.  Indicator lamps show power on or function status.

 

  •  RGB LED drivers allow simplified programmable control of LED color and brightness in an ultra small footprint package device. 
  •  3-channel RGB LED drivers permit customer color control
  •  4-channel RGBW devices allow for driving a white LED in addition to the RGB LED.
  •  Programming interface options include ExpressWire or I2C to ease integration with a wide variety of processors and operating systems.

 

Part NumberDescriptionPackagePackage Alt.Package Alt.1
KTD2021 3-Channel RGB LED Driver with ExpressWire Control TSOT23-6    
KTD2022 3-Channel RGB LED Driver with ExpressWire Control UTDFN-8 1.5x1.5mm    
KTD2023 4-Channel RGBW LED Driver with ExpressWire Control UTDFN-8 1.5x1.5mm    
KTD2026 3-Channel RGB LED Driver with I2C Control UTDFN-8 1.5x1.5mm    
KTD2027 4-Channel RGBW LED Driver with I2C Control UTDFN-8 1.5x1.5mm    

+ PoE PD Controllers  

 

The AS18xx family of parts support single and multi-output isolated solutions for IEEE802.3af (Type 1) and IEEE802.3at (Type 1 and Type 2) PDs.  Higher power levels may be achieved using custom programmed PSEs or by implementing the LLDP software interface to enable 4-pair power delivery on the Ethernet cable.  The AS18xx family, in addition to integrating the PD physical interface and DC/DC controller functions, adds synchronous rectifier control and integrated digital signal isolation thereby eliminating the need for opto-couplers.  The multi-output versions support up to three additional outputs, each of which may be individually sequenced.  Two of the outputs are integrated MOSFET synchronous buck converters.  The remaining output requires external power MOSFETs, but may be configured as either a synchronous buck or a non-synchronous boost converter.  All products include input and output over-current protection, output over-voltage protection, and over-temperature protection.

 

The AS18xx family is a complete PD power solution with full command/control and monitoring capability available through the integrated I2C bus.  The command/control features allow management of the power processing functions such as on/off control, voltage margining, sequencing of outputs, fault and alarm monitoring, and even input voltage and current.  Other PD functions may be controlled or monitored through the available general purpose digital ports.

 

The AS11xx family of parts provide solutions for PD controller and integrated primary DC/DC controller with single output isolated or non-isolated solutions for IEEE802.3af (Type 1) and IEEE802.3at (Type 1 and Type 2) PDs.  Higher power levels may be achieved using custom programmed PSEs or by implementing the LLDP software interface to enable 4-pair power delivery on the Ethernet cable. These highly integrated solutions provide industry leading performance in a small footprint with integration of front end rectification (AS1113 and AS1114), surge protection, advanced PoE and power management, enabling a flexible design.

 

The AS1113 and AS1114 PoE + DC/DC controller products address Type 1 PD applications. They are highly integrated CMOS solutions for PoE applications that provide seamless integration of Front End Rectification, Advanced Power Management, EMI Control and High Voltage Protection in the Industry’s smallest footprint.  

 

The AS1138 targets both Type 1 and Type 2 PDs.  It is a highly integrated CMOS solution for PoE PDs requiring input power up to 30 watts.  The AS1138 integrates input Surge Protection, a digital PD controller, and a low-emission DC/DC controller onto a single die.  The AS1138 implements the physical layer PD functionality as required by IEEE® 802.3af and IEEE® 802.3at.  This includes 2-event classification, a Type 2 PSE detection indicator (ATDET) in addition to PD detection, under-voltage lockout, and hot-swap FET integration.

 

Part NumberDescriptionPackagePackage Alt.Package Alt.1
AS1824 13W GreenEdge™ PoE PD Controller with HV Isolation, Quad DC-DC QFN-9x9-64L-0.9    
AS1831 13W GreenEdge™ IEEE802.3af PoE PD Controller with HV Isolation QFN-9x9-64L-0.9    
AS1834 13W GreenEdge™ PoE PD Controller with HV Isolation, Quad DC-DC, Software Mode QFN-9x9-64L-0.9    
AS1844 13-30W GreenEdge™ PoE PD Controller with HV Isolation, Quad DC-DC QFN-9x9-64L-0.9    
AS1851 GreenEdge™ IEEE802.3af/802.3at (13W-30W) PoE PD Controller with HV Isolation QFN-9x9-64L-0.9    
AS1854 13-30W GreenEdge™ PoE PD Controller with HV Isolation, Quad DC-DC, Software Mode QFN-9x9-64L-0.9    
AS1860 GreenEdge™ 60/90W PoE PD Controller with HV Isolation, Quad DC-DC Outputs, I2C QFN-9x9-64L-0.9    
AS1891 GreenEdge™ IEEE802.3af/802.3at 60/90W PoE PD Controller with HV Isolation QFN-9x9-64L-0.9    

+ EMI/ESD Protection  

 

EMC compliance for Ethernet connected devices often challenges the designer.  The physical interface of the PD data path to the outside environment is through the PHY.  The PHY is also subject to ESD and surge events when an Ethernet cable is inserted.  CM emissions are typically filtered by large passive devices located between the PHY and the LAN isolation magnetics.  Kinetic Technologies’ AS1602 is the world’s first active ESD and EMI suppressor IC.  It is a 4-channel device in which each channel connects to one wire of the two twisted pair sets.  ESD performance, EFT-B and surge immunity, and CM emissions equal or exceed passive techniques while occupying a much smaller footprint.

 

The AS1602 enables system designers to comply with:

 

  •  CISPR22 and FCC Part 15, Class B requirements for Radiated and Conducted Emissions.
  •  IEC 61000-4-3/6 requirements for Radiated and Conducted Immunity, Level 3 or higher.
  •  IEC 61000-4-2 ESD (Air Discharge) of ±25kV.
  •  IEC 61000-4-2 ESD (Contact Discharge) of ±12kV.
  •  Cable Discharge Event (CDE) of ±12kV.

 

Part NumberDescriptionPackagePackage Alt.Package Alt.1
AS1602 Dual-channel Active choke for EMI suppression w/ Integrated ESD Protection QSOP-16L (SOIC narrow)    

Copyright © 2017 Kinetic Technologies, a Cayman Corporation. Privacy Policy | Terms of Use