latching relay.

[alphadog]

Hello.

I found this latching relay driver:

**broken link removed**

The problem is that my latching relay has voltage rating of 5V (not 3V as in design), and rated coil power of 1W, and my GPIO pins of MCU can output only 3.3V (not 5V input as in design).
I do have a 5V VCC that comes from external power supply.

Is is possible to fit this design to 5V, 1W latching relay?

Thanks.

 

[colin55]

Your circuit will not interface (will not work) to a 3.3v microcontroller.
Here is a circuit for an "H-bridge" that will work on 5v and can be connected to a single output line of a microcontroller operating on a supply of 3.3v.
Simply connect the microcontroller to the base of Q3 and remove all the components from the front-end of the circuit.


**broken link removed**

 

[ccurtis]

Is is possible to fit this design to 5V, 1W latching relay?

I don't think so. First, your relay coil is only going to see about 3.5 volts, which may not be enough. Secondly, and worse, 3.0 from your MCU may not turn on the top Darlington pairs. It may work, but it's too close for comfort.

 

[blueroomelectronics]

You could try a TC4427, should make an excellent driver.
**broken link removed**

 

[alphadog]

blueroomelectronics

Hi, could you explain please how do you suggest to use it as a single coil latching relay driver?

Thank you.

 

[blueroomelectronics]

It's a dual half-bridge.
So
A=1, B=0 +/- out
A=0, B=1 -/+ out
A=B same out (no change on relay)

 

[alphadog]

I see. thanks.
Currently i have the ULN2003AID, which is not exactly the same bot has an inverter inside.

Do you know if its possible to switch single coil latching relay with it?
Here is its datasheet:
ULN2003AID pdf, ULN2003AID description, ULN2003AID datasheets, ULN2003AID view ::: ALLDATASHEET :::


Thank you.

 

[blueroomelectronics]

It's an open collector array. It doesn't drive outpours high plus it has the voltage drop problem. Why not use a dual coil latching. Very easy to drive.