TDK-Lambda RFE1600 Series, Installation Manual, Page: 31 / 36

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5.1.1 PMBus Interface Option
The communications bus signals are powered by an external 3.3V power source pulled up with a 1.5k
Ω
resistor.
5.1.2 RFE1600 May Have Optional Power Management Bus Hardware
The PMBUS interface in the RFE1600 (/S option) includes:

Monitoring the Output Voltage, Current and Temperature.

Programming the Output Voltage and Current.

Programming the Maximum allowed output Voltage.

Programming the Supply On/OFF.

Reading and Clearing Faults.

Reading the Manufacturing Related Data (Model Name, Serial No, Manufacturing Date, etc.).

Storing the following conditions at AC Off.
-
Set Output voltage.
- Max allowed programmable output voltage / Current limit (OCP).
ATTENTION:
If PMBus is used for voltage/current programming, the reference voltage will not be fixed to 5V but can be variable
(Reference voltage will be used for voltage/current programming).
The PMBUS supports:

100 KHz Operation.

Block Read Protocol.

Group Command Protocol.

Direct Data Format for Monitoring and Programming Functions
.
5.1.3 Addressing (A2, A1, A0 Inputs)
Four variable address lines allow up to 8 Supplies to be connected on a single bus.
PMBus uses 7 bit addressing.
There is constant part of address and variable part of address:
Constant part of address consists of 4 Most Significant Bits A6, A5, A4 and A3 always equals 0010.
Variable part of address consists of 3 Least Significant bits: A2, A1 and A0.
Value of these four bits have to be assigned by hardware connections of 3 pins of the PS connectors.
The Address lines (A2, A1, and A0) are internally pulled up by resistors to +5V.
The address lines can be left open for ‹1› address or connected to -S for ‹0› address.
So, available Address Space contains 8 possible addresses: from 0010000 to 0010111.
In case more than one unit is connected to PMBus, each unit must be set to its own unique address.
Duplicate addressing is not allowed.
For example:
First unit – A0(J2-1), A1(J2-2), A3(J2-3) are not connected – ADDRESS 0010111;
Second unit - A0(J2-1) is connected to -SENSE – ADDRESS 0010110;
Third unit – A1(J2-2) is connected to -SENSE – ADDRESS 0010101;
ATTENTION:
A2, A1, A0 signals and -SENSE are NOT isolated from the Output Terminals.
5.1.4 Serial Clock
This line is clocked by the Controller which controls the PMBUS. It should be connected to +3.3V
(Referenced to "Signal RTN") via a 1.5kΩ pull-up resistor.
5.1.5 Serial Data
This is a Bi-Directional line which must be connected to +3.3V (referenced to Signal RTN) via a 1.5kΩ pull up resistor.