Prabhakarankft
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The circuit inside the driver cards is so easy. We have a 74HC595 IC(P.No: 74HC595D,118 ) and ULN2803 (P.No: TBD62083AFWG).
Dear StenzerHi,
according to your initial post the solenoids are attached to ~15 V, but the freewheeling diodes are attached to 12 V. How does the actual connection looks like?
BR
... and some times one/two channels in the hex buffer.
Hello,Hi,
the HEX buffer is not shown in your partial sketch, and it seems it is also causing troubles/ is affected. Please provide the missing parts of your schematic and if possible a picture of your complete system. It is hard to get an overview only by the textual explanation.
BTW, the 74HC595D has a higher HBM ESD rating compared to the 74LS244N (MM not stated for the HEX buffer), thus the 74HC595D should be less prone to ESD (HBM). Therefore, the interconnection as well as the layout itself is of special interset to determine potential failure (ESD) causes.
BR
4. 595 controlling pins are working at 3.6V. data in pin working at 5V. 595 powered with 5V. Working with 2 different input voltages causes any problem??
Hi Stenzer,Hi,
please upload a larger version of your schematic, it is impossible to read anything.
You are using the HC version which has CMOS input levels, thus for a 5 V supply voltage, your minimum high voltage level is 5 V \[\cdot\] 0.7 = 3.5 V, which is pretty much on the edge. Have you ever tried the HCT version which has a minimum high-level voltage of 2 V?
BR
I am using ULN2803(P.No: TBD62083AFWG ) for driving solenoids 15V . It is having inbuilt free wheeling diodes/Clamp diode .Hi,
how does the connection of those ICs look like? I'm interested in the usage of the freewheeling diodes.
BR
It depends. What advantages do you think of?CMOS Level ICs are having many more advantages over TTL level.
If We use TTL level IC(74HCT595) need to change Hex buffers?
Really I am confused what is the use of Hex buffer here.
Dear FVM,In post #4, the indicator LEDs are supplied with Vcc (5V) which causes a violation of the maximal reverse LED voltage. Please correct.
Oh My god. It is typo.. 15V
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