3 Digit 7 Seg Digital Monostable

[Peterae]

I am going to design a digital monostable for use in various projects.

I will use digital delay lines DS1023, these come in various flavours 250 pS, 1nS, 2nS, 5nS

i will design so the 1nS,2nS can be used.

If 1nS chips are used then the monostable will allow a pulse width of 0-512nS in steps of 1nS

if 2nS chips are used then the pulse width will be 0-999nS in steps of 2nS

I will allow this to be set in software for display purposes and then it's just a case of plugging in the chosen chip.

everything will be through hole for easy construction.

A 3 digit 7-segment display will show the set pulse width.

The value will be set using a rotary thumb encoder, a switch on the shaft can be used to store the current setting for instant power up value.

I will provide a fast ttl buffer stage for the output pulse.

Input supply voltage 7-30V, on board 5v regulator.

Anything else people require or any other suggestions and i will see what i can do.

What plug does everyone want with the output pulse to appear on BNC???

[Peterae]

another option would be to use 1 off 1nS & 1off 2nS chips in series to produce 0-768nS in 1nS steps, i will add this function in software.

The first thing for me to do, is check they are still available at a reasonable price, they never were that easy to get but are available from Maxim.

I will also check to see if other brands are available as it has been about 5 or 6 years since i used this device.

[ion]

Peter

Looking forward to your further development of this. Maybe adding a couple of power FET sections with driver chips would also be good.

Regards, ION

[Peterae]

Hi ION
I can add a fet driver, so therefore we could have 0-5V out & Push/Pull 4 Amps 0-18V output.

I have found the DS1123 to be more easily available and half the price so will go with this, it's exactly the same as the DS1023 but a 3.3V device, this is not a problem as my PIC will work down to 2V and i was going to use a MC74VHC1GT08 OR gate buffer which work well as logic level translators 3.3V -> 5V anyway.

Output will be configurable for PWM or pulse delay so in theory 2 of these boards could be connected to phase delay and then PWM a signal.


I'm working on the diagram  

[Peterae]

OK here's the first draft

Turns out although i can chain multiple chips for longer delay or phase shift i cannot chain for PWM which means i am stuck at using a single delay chip.

Therefore the specs will be 0-255nS in 1nS steps using the DS1123-100

or

0-512nS in 2nS steps using the DS1123-200

Still need to add Fet Push/Pull 4A Driver 

[Peterae]

OK added FET driver

[Peterae]

OK final circuit and pcb

I used smaller sma sockets for pulse Input & Output

[Peterae]

I have attached a zip of the Eaglecad files including Gerber & ordered 10 boards

The PCB fabrication house that Les Banki uses ,their prices are dam amazing
DigmonoGerbers
Material: FR-4
Layers: 2
Board Thickness: 1.6mm
Copper Thickness: 1/1 oz
Surface Treatment: HASL
Green Solder mask, White Silkscreen
Dimension: 8.89*8.25cm

10 OFF

$16.11 + P&P