Re: XTB-II 2-Phase Version

[Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx>]

Hello Jeff,

>>
>>>>They wouldn't have to be. If you used a series resonant circuit and a
>>>>FET as the switch this should not present a serious load while the FET
>>>>is gated off.
>>>
>>>The XTB has an output circuit similar to what you describe.  But that
>>>doesn't help the problem caused by multiple X10 transmitters loading one
>>>another on a powerstrip plugged into the XTB X10 input receptacle.  The
>
>>>output driver is isolated from its input receptacle at 120KHz.
>>
>>Possibly because the design of the other transmitters is, ahem,
>>sub-optimal? If they'd all tri-state their output stages when not
>>transmitting they should not load down the line. Provided that any
>>output filtering to comply with agency regs is done correctly. A diode
>>T/R switch would be another option but isn't really needed for X10.
>>
>>My area of work is medical and there we often have a similar task,
>>running pulsers onto an analog bus that is also used for receiving.
>
> Ah!  So you probably don't have to design devices that can be built for a
> couple of bucks. ...


Actually, I do have to. The BOM budget for a pulser stage is usually
about that. Ultrasound machines often hold 64 or more of these so it
adds up. Then there is reimbursement by Medicare and programs like that
in other countries, also HMOs and other healthcare organizations. These
rates are often pretty slims. The days when "anything goes" are over for
medical with very few exceptions. Japan, for example, often has pretty
cushy reimbursement rates but that might also not last for too long.

Then when you design a system for the veterinary market you really have
to turn every FET around, to see if it can be done with a BJT for five
pennies less per stage.


>            ... I have done designs for both military and commercial
> applications.  They are vastly different worlds.  In one case we strive for
> performance.  In the other case we wonder how cheap can we make it and still
> have it work.  In this day and age, volume sales usually go to the cheapest
> products.
>

Other than defense that's probably true for most markets, including
medical. At least if you design for the long run and not for a cutting
edge research solution.

--
Regards, Joerg

http://www.analogconsultants.com