Hi Javid,

Our haptic piezo drivers are optimized for <20kHz signals (ideally for <500Hz). The particular devices that can drive 100Vp or 200Vpp differentially are the DRV8662, DRV2667, or DRV2700. The bandwidth for these devices will not reach the 22kHz mark even without a load.
How much capacitance is the piezo element? This will determine the amount of power you need to drive 200Vpp @ 22kHz.
From there, you will need to design a 100V or 200V boost converter stage and then you can use high voltage amplifier or FETs to drive the output stage.
There are a few other posts in the DC/DC Forum regarding the boost architecture using the PMP5161 or the LM3478/LM3488. For the amplifier stage, maybe the OPA454 or CSD19535 (or similar). Again these will depend on the power needed to drive your piezo load.

Hi Kelly,

Thank you for your reply. Would you be kind enough to address the following:

1. We already ordered DRV2700EVM-HV500 which, according to the description, reaches 500V Output. Is that correct? If so, can we drive it at 22kHz? piezo capacitance is really not a design parameter for us. We just want the piezo to resonate at 22 kHz with voltages above 200 p2p being applied to it (whatever capacitance that turns out to be). 

2. I also saw DRV2667EVM-CT + DRV2700EVM. Would these two get the job done? We're at experimental stage so if any of these deliver, we can move on to designing a specific board with DRV8662, DRV2667, or DRV2700. 

Hi Javid,

1. Yes, the HV500 design can reach 500V and these parts are designed to drive piezo loads. However, they have a maximum power rating. For the HV500 design you can refer to Figure 13, Instantaneous Max Load Current vs Max Output Voltage. As the current increased, the max output votlage decreases. This is where the key spec from the piezo element comes into play. You can use this tool to calcualte the current needed for your piezo. The current is determined by the frequency (22kHz), voltage (200V), and the capacitance (?nF) [FYI - the equation for Iout_max is missing the "2" multiplier]. This is why you need to know the parameters of the piezo element..

2. Both of those devices can drive 200Vpp differentially, but their bandwidth at 200Vpp is limited to 5kHz with no load (no piezo capacitance..). As you add a load on the outputs, the bandwidth will decrease because our device cannot provide sufficient power.

Hi Kelly,
Thanks a lot for the info. I'm not an electrical engineer so I apologize if I am reiterating my previous question. It turns out the piezo we have in mind resonates at 22 kHz, with 52600pF static capacitance. If we run it at 200V p2p, can we use the DRV2700EVM-HV500? I'm asking because we have already order DRV2700EVM-HV500 and I need to know what to expect. From Figure 13 of the data sheet, it seems that the for 200V, the Instantaneous Load Current is 5 [mA].

Hi Javid,

That's ok. The answer is no, that design can't provide enough power to charge the piezo at 22kHz. Using the equation for a capacitor, i=C*(dv/dt), the instantaneous current into the capacitor is ~230mA in order to charge the cap to 200V in (1/22000)ms. So you need ~50 times more power.
You will need a high power design to achieve this. If you can share, what is the piezo element being used for? Does it need to run at the resonance frequency or are you using it in a haptic feedback application?

ouch!
Sure, the Piezo unit is STEMINC part# SMUN15MT19F22111. We need to run it at the resonant frequency for ultrasonic cleaning purposes. Hence we need to design a board for this specific purpose. Currently, in the lab we use a function generator coupled with a high frequency voltage amplifier to run the piezo at 22 kHz with square waves at 400 volts p2p. I was optimistic we can get off-the-shelve boards that can deliver the load at the frequency wee need. Any suggestion at this point is greatly appreciated.