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HVES for smoothing consumption peaks

Thread Summary

The user seeks ICs to smooth power consumption peaks in a POE-powered device with a 15W limit. The MAX5996C can manage constant power limits, but the system must implement a secondary circuit to handle peak power draws of 30W. A UVLO circuit can signal when additional power is available based on output voltage.
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Category: Datasheet/Specs

Hi,

I'm looking for ICs for a specific power management task.
The scenario is to store energy in electrolytic capacitors to then use it during increased-consumption periods.
Next I will describe the example in more detail.

Let's say, the device is powered by POE source with limited power, 15W.
The average consumption of the device does not exceed this limit.
But, the device's consumption is not uniform. For 20 seconds it consumes 10W, then for a second it consumes 30W. And so on in a cycle.
The idea is that when the device consumes little power, the power from the source is used to power the device and charge the capacitors, and when the consumption is high, the energy from the capacitors is added to the source.

The supply voltage of the device's electronics is 5 volts. The POE voltage of 37-57 volts is converted via DC-DC converter to those 5 volts.
Somewhere between the POE and the final DC-DC, an energy management/storage/splitting/joining circuit can be placed. The capacitors can be high voltage for greater efficiency.
Perhaps the circuit should be able to provide the device with information "the charge is sufficient, you can use more power".

Is there anything in AD's products that is suitable for this task of smoothing consumption peaks?

  • Hello,

    This may not be the exact solution your looking for, but the MAX5996C may operate with a constant power limit when paired with a DC-DC converter, see Figure 5 from the datasheet below:

    The system should either have a load that can tolerate the output drooping during constant power limit events, or diode OR another supply at the output for droop sharing. The MAX5996C automatically sets its power limit based on its PoE classification. If it's allocate Class 3 (15W at source), then it will limit power to 12.65W typical. It will then be up to the system designer to implement a circuit that sources the additional 18W for the duration of the peak power draw. This circuit would need to be on the secondary-side or output of the DC-DC converter, but it would be simple to implement UVLO circuit to signal more power may be drawn based on the output voltage.

    Best Regards,

    Eric