Re: [EE] Looking for serial high-side relay driver

Hi Dwayne,

Seems I'm regularly looking for something like this too, and similarly have employed 
the TPIC6A595 with 8 x low side outputs.

There are not too many choices for multi channel high side smart drivers with a 
serial interface. TI has some interesting 4 x channel devices worth looking at. But 
one I've just noticed is the  Infineon TLE75080 with 8 x channels, nominal 330mA 
per channel, high side, SPI for control and diagnostics, reasonable price.

Brent

On 15 May 2025 at 14:21, Dwayne Reid wrote:

> Good day to all.
> 
> I'm retrofitting an existing product that uses lots of 12 dc or 24 Vdc
> relays.  These relays all have one side of the coils grounded and take
> incoming battery supply to activate.  We are adding a pair of cards that
> allows the relays to be controlled over a 4-wire interface (Gnd, Vbatt,
> data, data).  I have not yet decided whether to implement a simple SPI
> interface or RS-485, based on what options the customer wants.
> 
> My old standby relay drivers (TPIC6595 or TPIC6C595) are not suitable
> because they are low-side switching.  My question is: is there a modern
> equivalent that does hi-side switching?
> 
> Another option is to float several 74HC595 shift registers from the
> incoming battery supply line and use a whole whack of 2N4403 transistors /w
> clamp diodes to drive the relay coils.  I would then probably use
> opto-isolators to get the signals into the chips.  I will do this if that
> is my only option.
> 
> Suggestions greatly appreciated!
> 
> Many thanks!
> 
> dwayne