LM3464EVAL: AC/DC converter output

Hello Steven,

I am moving this to the LED group that supports this part.  I used to support this part in the past.  The power supply portion is assumed to be an isolated DC output with a reference that can be connected to.  It isn't covered as part of the design since there are many different designs that can be used.  I would search for AC/DC isolated power supply designs to fit your application.  Even an off the shelf power supply could be used if the feedback circuitry can be configured for this.

"Selection of AC/DC Power Supply
The LM3464A evaluation board can be powered by an AC/
DC power supply through the banana-plug type connectors
on the board as shown in figure 2. Assuming the nominal forward
voltage of one LED is 3.5V, the total forward voltage of
a LED string containing 12 LED is about 42V. In order to reserve
extra voltage headroom to compensate the variations
of the LED forward voltages due to changes of operation temperature,
the LED turn ON voltage of this evaluation board is
set to 48V. As this evaluation board is designed to deliver
350mA for each output channel, which is about 60W output
power at 48V rail voltage, the AC/DC power supply must be
able to supply no less than 60W continuous output power at
48V. Therefore, a 60W AC/DC power supply with 48V output
voltage is needed.
In order to facilitate Dynamic Headroom Control (DHC), the
output voltage of the AC/DC power supply is adjusted by the
LM3464A. The LM3464A adjusts the output voltage of the AC/
DC power supply by sinking current from the output voltage
feedback node of the AC/DC converter through a resistor
RDHC into the OutP pin according to the dropout voltage of
the linear current regulators. The OutP pin of the LM3464A is
a open drain pin that can only sink current from the voltage
feedback node of the AC/DC power supply, thus the
LM3464A evaluation board is only able to increase the output
voltage of the AC/DC power supply to acquire wider voltage
headroom.
Since the output voltage of the AC/DC converter will be increased
by the LM3464A to allow dynamic head room control
(DHC), the nominal output voltage of the AC/DC power supply
must be reduced prior to connecting to the LM3464A evaluation
board to reserve voltage headroom for DHC to take
place. This is achieved by modifying the resistance of the
output voltage sensing resistors of the AC/DC power supply.
To adapt the AC/DC power supply to the LM3464A evaluation
board, the nominal output voltage of the AC/DC power supply
is recommended to be reduced from 48V to 36V. Usually, the
nominal output voltage of the AC/DC power supply can be
reduced by changing the resistance of the resistor divider for

output voltage feedback. Figure 2 shows the voltage feedback
circuit using LM431 which has been widely used in
typical AC/DC power supplies as an example.
To reduce the output voltage of the AC/DC power supply from
48V to 36V, the resistance of R2 is increased without changing
the value of R1. The output voltage and value of R2 are related
by the following equations:"

This is from the application note of the evaluation board, AN-2071.

Best Regards,

Thank you for the response, however I am certainly sure you did not answer the question. Finding a power supply with the correct configuration you are saying is very difficult. So I understand what you are saying is there are many different designs that can be used for this. However, when TI designed LM3464EVAL board they must have used a power supply for testing. What was that being used?

Also, there must be some form of BOM that has the recommended parts just for the feedback portion of the AC/DC converter. Is that archived anywhere so that I can receive it?

Also, I am assuming that you will not be able to provide a power supply, thefefore, I would like to have the recommended parts for the AC/DC converter output feedback as given in the EVAL Data sheet

Irwin, has the thread been moved to another post or will you be the one responding to my previous messages on this topic? Do I need to create a new thread?