Hi,

I am designing a driver circuit of multi-channel MEMS device and have difficulty to transfer single driving signal to selected one among multi-channel MEMS devices.

My solution that I can think for my application is use of many relays (SRD) and form one-to-N channel DEMUX by using N pieces of the relays.
- e.g. single input to twenty outputs --> use of twenty relays

The difficult parts are,
- that the input signal to route is arbitrary waveform of high voltage (+0 to +160Vpp) and DC-to-high frequency (DC to 10kHz)
- and that required number of output channels is more than twenty (the more, the better).

I want to mention that the current of input signal is very small (less than 0.05 mA).

I think the design seems not good because it requires many relay devices and PCB space. I also worry about disturbance/noise and capacitive load issues due to many connections from single input.

Would anyone please suggest me a solution or recommend me proper DEMUX device for this application?

 

Is the signal a square wave, sine wave, triangle, saw, narrow pulses, ???

What is the circuit that is producing the signal? Schematic?

ak

 

You can use solid state relays, like for example AQY410s, or similar. Very small space and should have no trouble doing what you need, just check that the open state capacitance is low enough to not influence your circuit.

 

Explore alphanumeric fluorescent display driver ICs. Barely remember their circuits from early TDD devices I used to play with. It may be applicable to your needs. Sorry am not able to be of more help now.

Perhaps somewhere in :

----> https://duckduckgo.com/?q=fluorescent+display+high+voltage+demultiplexer++ic&t=canonical&ia=web

 

You can use solid state relays, like for example AQY410s, or similar. Very small space and should have no trouble doing what you need, just check that the open state capacitance is low enough to not influence your circuit.

Interesting idea. The off-state leakage current in chart #9 is creeping up on 1 uA at higher voltages, 2% of the on-state signal current.

http://www.datasheetarchive.com/pdf...4caf7880cde97a124ed608c39&type=M&query=AQY410

ak

 

I doubt this exact type would be ideal, but the general direction could lead to something useful.

If the switching frequency is low, then another possibility are two back to back mosfets driven by photovoltaic mosfet driver like VOM1271. Not cheap, but quite small, and you can choose the fets to better match the application.

 

Dear AK,
Dear kubeek,
Dear Externet,

Thank you all for your replies. I would like to add more information about the MEMS driver. Please, give me any comments if possible.

1. Signal input for the routing is user-defined continuous arbitrary signal so it can be any of the standard waveform. The input signal source device is an op-amp (i.e. HV264). Please, find URL below for more information on the op-amp.
https://www.microchip.com/wwwproducts/en/HV264

2. The simple block diagram of the MEMS driver is as shown below.

[Digital input]–[16bit ADC]–[op-amp]–[Analog output]

where, the Analog output is the signal input for the routing.

3. The routing bandwidth of DC-to-10kHz is needed. But the bandwidth of DC-to-5kHz or DC-to-100Hz could be a good solution if there are advantages on number of channel, form factor (or size), reliability, availability, and so forth.



I summarized your comments below to check whether I understand or not. If there is mistake, please let me know.

Method one: Solid state relays (e.g.AQY410S)
- Open state capacitance should be low enough to prevent influence on the circuit.
---> Would you please explain about what open state capacitance is?
- The off-state leakage current in chart #9 is creeping up on 1 uA at higher voltages, 2% of the on-state signal current.
---> May I ask you why it is an issue?

Method two: Alphanumeric fluorescent display driver ICs

Method three: Two back to back mosfets driven by photovoltaic mosfet driver (e.g. VOM1271)
- Low switching frequency (77 us or 13 kHz)
---> If it means just switching speed of routing, it is enough speed for my application.

Method four: Relay (i.e. SRD)

Thank you,

Hyunduk Shin

 

I am a little lost, are you looking for one output to multiple inputs type arrangement, or the opposite? In any case, what is the input and output impedance of the outputting device and of the receiving device?
Open state capacitance should be low enough to prevent influence on the circuit.
Meaning that when the switch is supposed to be open, there is still some capacitance between the two pins, and possbily also some leakage resistance that allows that 1uA to flow. This will lead to that the devices that should be disconnected will still be connected through this high impedance, which may influence the useful signal.

 

[Digital input]–[16bit ADC]–[op-amp]–[Analog output]

This part is partially incorrect. The second block is a DAC.

The analog output is the single input into an analog demux with multiple independent outputs.

Since HS already has a very compact, low cost MEMs driver, I don't think anything will take less room than putting the demux circuit after the opamp. Then have 4 MEMs driver chips, one for each 4 output channels. This will eliminate any issues with the demux circuit affecting the high voltage supply, corsstalk, etc.

[Digital input]–[16bit DAC]–[op-amp]–[1:16 demux circuit)-[16 MEMS Drivers (4 chips)]

ak

 

Dear kubeek,
Dear AK,

Thank you for the explanation and the correction.

I could derive conclusion from your help. Any comments will be highly appreciated.





Thank you,

HS

 

What are you doing that requires over 100 TENS pads?

ak

 

What are you doing that requires over 100 TENS pads?

ak

Thank you for your comment.

The target device is an array composed of many micro devices. (e.g. http://www.mdpi.com/2072-666X/7/1/14)

HS

 

I misread post #1. oops.

ak