Freescale - IEEE 802.3af PD With Current Mode Switching Reg - 18 June 2012

The 34670 combines a Power Interface Port for IEEE 802.3af Powered Devices (PD) and a high performance current mode switching regulator.

It allows a designer to build PDs with a minimum of external components by means of integrating the required IEEE 802.3af functions and all functions necessary to build a high efficiency DC/DC converter.

On the PD side, the 34670 fully supports the IEEE802.3af standard and provides complete signature and power classification functions.

It controls inrush current limiting and incorporates adjustable undervoltage lockout. The switching regulator provides excellent line and load regulation. It drives an external Power MOSFET with sense resistor.

Product page

Datasheet

PD Interface

Integrated IEEE 802.3af Compliant Interface
Signature Detection and Classification Functionality
Integrated Isolation Switch
Programmable Inrush Current Limiting Control
Adjustable Undervoltage Lockout
Input Voltage Range up to 80 V

PWM Controller

No auxiliary winding necessary, device directly supplied from VP WR
Current Mode Control offers fast response and perfect stability
Adjustable Oscillator
Leading edge blanking
Internal slope compensation circuitry
Overvoltage Protection

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