1.4

Current Limiter

This circuit continuously monitors the current of powered ports and limits the current to a pre-defined value set by

AF/AT/BT/PoH. When the current value exceeds this specific value, the system starts measuring the elapsed timing.

If this interval is greater than a preset threshold, the port is disconnected.

1.5

Main Power MOSFET

The main power switching FET is used to control PoE current into the load.

1.6

10-Bit ADC

A 10-bit analog to digital converter (ADC) is used to convert analog signals into digital registers for the logic control

module.

1.7

Power on Reset

Power on Reset (PoR) monitors the internal 3.3 V and 5 V DC levels. If this voltage drops below the specific

thresholds, a reset signal is generated and the manager is reset.

1.8

Voltage Regulator

The voltage regulator generates 3.3 V and 5 V for internal circuitry.

1.9

Oscillator

The manager’s clock (CLK) is an internal 8 MHz clock oscillator.

1.10

SPI Communication

The managers use SPI communication in SPI slave mode to communicate with the MCU. Each manager has an

address determined by ADDR0-ADDR3 pins. Addresses 0–11 are supported. The frequency between controller and

manager ICs is 1 MHz.

PD69208T4/PD69204T4/PD69208M

Functional Descriptions

Datasheet

DS00003428C-page 6