Hi
I'm supposed to build a buck type interleaved converter with specs roughly 100V input 36 V output with total power near kW level. I could not find a controller IC aimed for this kind of converter.
TPS4009 seems a very good solution however it is specifically written in its datasheet that this product aims low power high current applications.
How come a controller dictate input output voltage levels and power of a converter? Its duty is mainly create an error signal, amplify it accordingliy and produce duty cylce, isn't it? Or, are the voltage values i see recommended for IC supply, i.e can i use this controller in a higher rating converter with an auxillary converter dedicated for feeding IC? Will it be okay if i take the output voltage information with a divider then feed it to the IC? Or, is there any other solution?
I appreciate any comment or help
Thank you
Hi Ilker,
The major concern for using TPS40090 for high voltage, high current application is how to feed the high output voltage into the remote sense amplifier and current sensing signal into the amplifier which is only designed for 4V max common mode voltage.
If remote sense is not necessary, you may consider not using it by connecting the FB directly to the output voltage divider.
For current sensing, higher output voltages can be supported by adding a resistor divider between the switch nodes and the output voltages, and ground. This reduces the common mode voltage levels seen by the controller’s current sense inputs, but also reduces the differential sense current and add some additional error to the phase balancing. Because of this, 0.1% accuracy resistors are recommended in the divider.
Regards,
Na
Na, I also would like to use the TPS40090 as a higher voltage buck. My supply output is 21vdc.
I plan to use a differential amplifier (opa235) to subtract out the 21 volt offset.
Do you think that I can get by with a simple opamp or do I need to look for an isolating opamp?
Will
Hi William,
The common mode input voltage will be 21 V. I don't think OPA235 can allow this high input voltage. You may also consider using resistor divider to lower down the common mode voltage for current sensing signals.