The leading edge of the DC pulse from the controller.

Would 1N4001 diodes work in the above?

Rule of thumb is a PIV of 10x the operating voltage.
So a diode with 100V PIV.....1N4002 or better.

 

The leading edge of the DC pulse from the controller.

Would 1N4001 diodes work in the above?

Yes.

 

Rule of thumb is a PIV of 10x the operating voltage.
So a diode with 100V PIV.....1N4002 or better.

Whose thumb?
The highest reverse voltage the diode has to withstand is the supply voltage.
When the diode suppresses the spike it is conducting not blocking.

 

You can either use 470k/1uF and the 74LVC1G17 schmitt trigger (as drawn) and yes, the 74LVC1g17 needs a 3.3V supply and ground;
or you can delete the schmitt trigger and use 10k instead of 470k, and 47u instead of 1u, connecting the junction of the 10k and 47u directly to pin 2.

I assume 5 watt is fine? and that's a 0.47 ohm resistor from pin 7?

 

I assume 5 watt is fine? and that's a 0.47 ohm resistor from pin 7?

It was 0.47Ω in my original Albright circuit, you'll need 0.22Ω 1W for your solenoid.

 

I can't find any US sources for either A4953 or DRV8870. All give back order to 1H22. I can find them on Amazon in lots of 10 but they ship from China and won't arrive until Mid August (better than next year).

Is there a difference between DRV8870DAR and DDAR versions? Do these things fit on a breadboard?

 

Whose thumb?
The highest reverse voltage the diode has to withstand is the supply voltage.
When the diode suppresses the spike it is conducting not blocking.

ah...no..
Back EMF is many time higher than the supply voltage.

 

ah...no..
Back EMF is many time higher than the supply voltage.

It is in the absence of a suppression diode!
With a suppresion diode the relay's back EMF is limited to the forward voltage drop of the diode. The diode is reverse biassed most of the time, so it's PIV has to withstand no more than the supply voltage.

 

I can't find any US sources for either A4953 or DRV8870. All give back order to 1H22. I can find them on Amazon in lots of 10 but they ship from China and won't arrive until Mid August (better than next year).

They are tricky to get at the moment! (What isn't?) I've just had to swap from the Allegro to the Texas - that's how I know that they are equivalent.

Do these things fit on a breadboard?

No, because they have heatsink connections on the back that have to be soldered down.

Is there a difference between DRV8870DAR and DDAR versions?

DAR comes in tubes of 75, DDAR comes in reels of 2500. That's the only difference.

There's not many other choices - you're back to two relays or four transistors. Solenoids are nasty things to drive with relays - they like to draw an arc and vaporise the relay contacts when the relay switches off.

Here's the same circuit in easy-to-get components which will fit a breadboard.
The four diodes can be a 2A bridge rectifier, or four 1N5400.
All those parts are what is inside the DRV8870!

 

They are tricky to get at the moment! (What isn't?) I've just had to swap from the Allegro to the Texas - that's how I know that they are equivalent.


No, because they have heatsink connections on the back that have to be soldered down.


DAR comes in tubes of 75, DDAR comes in reels of 2500. That's the only difference.

There's not many other choices - you're back to two relays or four transistors. Solenoids are nasty things to drive with relays - they like to draw an arc and vaporise the relay contacts when the relay switches off.

Here's the same circuit in easy-to-get components which will fit a breadboard.
The four diodes can be a 2A bridge rectifier, or four 1N5400.
All those parts are what is inside the DRV8870!View attachment 244349

I assume the TC4426 TC4427 is OR (one or the other)?

 

I assume the TC4426 TC4427 is OR (one or the other)?

Yes - they will both work, so will any other low-side MOSFET driver IC - even though it's driving bipolar transistors.

 

Yes - they will both work, so will any other low-side MOSFET driver IC - even though it's driving bipolar transistors.

1 watt is good enough for the 470K resistor? what kind of capacitor is the 1 uf - electrolytic? ceramic? or other? Thanks

 

1 watt is good enough for the 470K resistor? what kind of capacitor is the 1 uf - electrolytic? ceramic? or other? Thanks

470k: 1/8th Watt would do! 1uF = anything.

 

They are tricky to get at the moment! (What isn't?) I've just had to swap from the Allegro to the Texas - that's how I know that they are equivalent.


No, because they have heatsink connections on the back that have to be soldered down.


DAR comes in tubes of 75, DDAR comes in reels of 2500. That's the only difference.

There's not many other choices - you're back to two relays or four transistors. Solenoids are nasty things to drive with relays - they like to draw an arc and vaporise the relay contacts when the relay switches off.

Here's the same circuit in easy-to-get components which will fit a breadboard.
The four diodes can be a 2A bridge rectifier, or four 1N5400.
All those parts are what is inside the DRV8870!View attachment 244349

I got the parts, I'll put it together this weekend. A question - the 1 uF capacitor connects to ground - is that the same as the 0V above the cap? Might be a stupid Q but just want to make sure. Thanks,

 

I got the parts, I'll put it together this weekend. A question - the 1 uF capacitor connects to ground - is that the same as the 0V above the cap? Might be a stupid Q but just want to make sure. Thanks,

Yes - all grounds are common.

 

They are tricky to get at the moment! (What isn't?) I've just had to swap from the Allegro to the Texas - that's how I know that they are equivalent.


No, because they have heatsink connections on the back that have to be soldered down.


DAR comes in tubes of 75, DDAR comes in reels of 2500. That's the only difference.

There's not many other choices - you're back to two relays or four transistors. Solenoids are nasty things to drive with relays - they like to draw an arc and vaporise the relay contacts when the relay switches off.

Here's the same circuit in easy-to-get components which will fit a breadboard.
The four diodes can be a 2A bridge rectifier, or four 1N5400.
All those parts are what is inside the DRV8870!View attachment 244349

I have the parts. Just need to find time to put together.

Can someone please explain how this operates? It will help trouble shoot when I screw up as well as expand my knowledge. I'm curious how it converts a steady high input into a pulse and likewise when the input goes low, how it sends an opposite polarity pulse. Thanks

 

The top end of the solenoid is at 0V when it should be open and at V+ when it should be closed.
So is the other terminal of the solenoid, but it is delayed.
Most of the time, both terminals of the solenoid are at exactly the same voltage, so there is no voltage across the solenoid.
The important bit is what happens during the delay.
The top end goes to V+, but the bottom end is delayed, it is at 0V, so there is positive voltage across the solenoid, briefly, until the bottom end catches up.
When the top end goes back to 0V, the bottom end is delayed, and remains briefly at V+, so there is negative voltage across the solenoid.