LMP8646: Constant Power

Hello Ikon,

Thanks for considering to use Texas Instruments in your design. This device can be used to measure the current through a shunt resistor or the voltage across a shunt resistor. Through these functions it can be part of a feedback loop that can regulate your system. Can you provide some details on your system including your common mode voltage and current range as well as how you are planning on implementing the constant power? From that we may be able to tell you if what you want to do is possible or if we have an alternative approach.

Hi Patrick,

Brief description of the design as below.

Used UCC28600  flyback controller IC as an example.

The concept is the same, using Flyback PSU +  LMP8646

Basically we want to know if we integrate the  LMP8646, into the secondary side of the flyback design (eg UCC28600),

Can it be configured to provide a constant power functions, since LMP8646 have adjustable gain features.

Thanks.

Hello Ikon,

I suspect that could be a problem as the bandwidth of the LMP8646 is around 1kHz and the UCC28600 control loop bandwidth is 2.6kHz. So I suspect there will be conditions in which the LMP8646 struggles to keep up. Also if you replace the photo-resistor with the LMP8646 you remove any benefits you would have have from isolation.