Extremely high zener current in oscillator

[KlausST]

Hi,

Oh, you look for an "attractive" one?
This is not a technical information...so, what does that mean?

When I do a quick selection at farnell, then I find more than 50 analog switches with
* single supply voltage >= 36V
* R_on <= 100 Ohm

Starting below 1$..

I wonder where and how you did your search..

Klaus

 

[FvM]

The 2k load specification has never been confirmed, so it's not yet clear about what kind of analog switch, comparator, driver or whatsoever we are talking here.

Please don't tell it's printed 2k so it means 2k. Because in other schematics of yours nothing is at it seems...

 

[Zak28]

The 2k load specification has never been confirmed...

The load should not drop below 1k, the load is very much variable from few megs to 1k.

...I wonder where and how you did your search...

I browsed thru digikey extensively. Farnell only has 2 switches applicable DG411DQ-T1-E3 seems ideal, not sure were you searched. I now believe this is the way to go 1 IC for the whole bridge just not sure whether short circuit protection is needed because shorts are very likely to happen with the use of the circuit.

 

[KlausST]

Hi,

Farnell only has 2 switches applicable DG411DQ-T1-E3 seems ideal, not sure were you searched.

Especially for you I did the farnell search at the US site:
https://www.newark.com/w/c/semicond...-to-44v&range=not-exc-nic&sort=P_MAN_PART_NUM

As you can see there are 124 switches with supply voltage >=36V and R_ON <= 100 Ohms.


Klaus

 

[Easy peasy]

easy enough to set up a 555 as a 50% osc [ 1 res from pin 3 to 2+6 ] and use another 555 as an inverter [ pin 3 from 1st 555 to pin 2+6 on the 2nd one ]

then you can buffer the outputs (if necessary) and drive your load ... from pin 3 to pin 3 ...

)

 

[Zak28]

easy enough to set up a 555 as a 50% osc [ 1 res from pin 3 to 2+6 ] and use another 555 as an inverter [ pin 3 from 1st 555 to pin 2+6 on the 2nd one ]

then you can buffer the outputs (if necessary) and drive your load ... from pin 3 to pin 3 ...

)

Agreed however I rather employ ltc6995, more precision, less power, less pins and less parts to use, inverting can be with oamp or logic inverter. I will eventually get this project fabbed, I can upload pics and board layouts for those who would like to view it.

 

[c_mitra]

If your load impedance is high and the current demand is modest, you can certainly drive the load with the switches directly (no need to bother MOSFETs) - if you decide to use a 4 channel switch. Drive the switch with a hex inverter relaxation osc or if you want, a 555 timer. You can use a zener to power the 555.