Need a circuit for interfacing latching relay to micro controller

Discussion in 'Embedded Systems and Microcontrollers' started by Mayuri1234, Mar 18, 2016.

  1. Mayuri1234

    Thread Starter New Member

    Apr 7, 2014

    I am using pic16f1787 as my main controller. I want to use a latching relay to interface with the controller. Attached is the datasheet for the relay.

    I am aware that there are two types of latching relay-single coil relay and dual coil relay.

    I need a circuit for both relays so that I can choose the one with less hardware and implement the design.

    Please help.

  2. crutschow


    Mar 14, 2008
    The dual coil relay will require two transistors (either two MOSFETs, or two BJTs with two resistors) and two diodes.

    The single coil design will require 4 MOSFETs connected as a bridge and no resistors and diodes, or 4 BJTs connected as a bridge with 4 diodes and 4 resistors.
    Either configuration will require two outputs from the micro, one for set and one for reset of the relay.

    If you tell me which configuration you prefer, I can post a conceptual circuit.
  3. Sensacell


    Jun 19, 2012
    Are you sure the single-coil unit requires a polarity reversal to unlatch?
    I think it's just bi-stable- latch-on, latch-off every other pulse?
    This configuration would be easy to manage if you could monitor one set of contacts with and IO pin to determine it's current state.