Notecarriers Efficiency Difference?

Hardware
1

Hi everyone,

I would like to better understand the efficiency difference between Notecarriers that use Schottky diodes versus those that use an ORing IC for power source protection and selection.

For example, the Notecarrier F uses Schottky diodes (FSV1045V) with a forward voltage drop of approximately 0.44V. In contrast, Notecarriers that use an ORing IC can have an equivalent forward voltage drop as low as ~0.12V, which is significantly lower.

From an efficiency perspective, this seems relevant — especially when operating from a LiPo battery with a nominal voltage of 3.7V. In the case of the Notecarrier F, after the Schottky diode drop, the effective voltage would be around 3.26V.

My questions are:

  • How significant is the real-world efficiency difference between these two approaches?

  • Does the higher forward voltage drop of the Schottky diode meaningfully impact battery life?

  • Are there other trade-offs (thermal performance, reliability, cost, transient response) that justify choosing one method over the other?

I’d appreciate any insights or measurements from practical experience.

Thanks in advance.

3

Hi @yordanyre and welcome to the Blues community!

Great question. Let me start by pointing out that we always avoid using normal PN diodes, as they tend to have a high FVD and an efficiency of about ~80%. In most of our Notecarrier designs (i.e. ones that are commonly used for prototyping only) we use Schottky diodes which tend to have much lower FVD and an efficiency about ~90%-95% (they tend to be “good enough” for most cases). In our most power sensitive designs we use Ideal Diodes which have an efficiency of about ~99.5% or better, and zero FVD.

What you point out re: the forward voltage drop of the Schottky diodes is true, but remember that’s effectively looking at a worst case situation of multiple amps, whereas with Notecard you’re usually in the tens of uA to 100s of mA (at most) range with very brief higher current bursts. So, not to dismiss your questions, but most of the issues are almost negligible when it comes to current usage of the Notecard/Notecarriers unless you’re in an extremely sensitive power usage scenario.

Thanks,
Rob

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