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I want to brake the connection between 2 traces on my pcb if i need to. the input is 12v (cars voltage 12v-14v) from the cars brake signal and the output goes to my device that uses the brake signal. i want to be able to cut this connection so the device does not receive the brake signal anymore.

I tried to use the MAX4544 but i don't know if this is the best solution. the problem i have with below schematic is that when COM gets 12v V+ goes from 5v to ~8v.

Maybe there is a better way to do this different ic or schematic.

I already have a opto coupler to sense the brake signal to my MCU. Maybe its better to use this digital signal to drive a mosfet to output the 12v to device and use a analog switch to cut the digital line to the mosfet. But i would lose the safety part to have it NC.

my knowledge it not this extended so i am looking forward to suggestions and idea's

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  • \$\begingroup\$ brake ? (to brake = remmen (Dutch) ) you mean: break the connection. You don't tell us what kind of signal you have, how much current needs to flow ? You cannot use (almost) any chip to switch a 5v - 8 V signal when the chip runs on 5 V. The supply voltage MUST always be larger than the largest voltage you're switching. I suggest not using a chip but to use a relay. Much easier to work with and understand. Cars are already full of relays anyway because they're robust. \$\endgroup\$ Mar 6, 2017 at 20:24

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Try using an analog switch or relay that is more apropriate for the application.

The MAX4544 datasheet states that COM must not be higher than V+ +0.3 V.

An analog switch like ISL43210A or similar can handle +15 V supply and the same voltage on the switched lines. And it is controllable by 5V logic without separate logic supply. Vishay, Rohm and many others have similar products.

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