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I'm trying to couple multiple piezoelectric discs as parallel to get electrical energy through vibration. using LTC3588 rectifier , which way is correct:

  1. wiring all piezo parallel,then connect output to a single ltc3588?
  2. use discrete ltc3588 for each piezo, then after rectifying connect them all together as parallel to increase output current?

    P.S: this circuit is going to be used as a charger for a 3.7 V rechargeable battery , and this is cause of focusing on parallel wiring(increase output current).

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    \$\begingroup\$ Think about the implications of both approaches. Can you guarantee that the vibration is in phase at all your transducers? What happens (with each approach) if it isn't? \$\endgroup\$ – Brian Drummond Aug 25 '17 at 13:46
  • \$\begingroup\$ @BrianDrummond this is exactly the reason i'm asking this question here \$\endgroup\$ – alex Aug 26 '17 at 6:41
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Assuming that all the discs are vibrating in unison then you won't need multiple LTC3588 devices. However, I'd be tempted to think about a series arrangement for the piezo discs. With two in series you will get twice the terminal voltage of one (at the same current) and, in some cases this will make an easier power conversion for the LTC3588 chip because the internal volt drop across the diode bridge will be a smaller proportion of the overall piezo voltage.

If you look on page 4 of the data sheet it tells you how much volt drop is incurred and it is largely a function of current and, having the piezos in parallel produces a bigger current at the same voltage.

For reference, page 11 says: -

Piezoelectric elements can be placed in series or in parallel to achieve desired open-circuit voltages.

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  • \$\begingroup\$ you are right , by increasing input current we will have more voltage drop in rectifier diods, but i'm thinking about charging a 3.7V lithium ion battery through this circuit, so maybe coupling piezoelectrics as parallel would be a better choice. but still im not sure \$\endgroup\$ – alex Aug 26 '17 at 6:35
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    \$\begingroup\$ The voltage you ultimately generate has little bearing on it because a power efficient buck regulator is used. However, the optimum position you might take is a series and parallel configuration. Try different scenarios is my advice. \$\endgroup\$ – Andy aka Aug 26 '17 at 9:14

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