I need the following SPI relay driver.

See http://focus.ti.com/lit/ds/symlink/tpl9202.pdf

I live in the uk. Does anyone know where I can order this online?

Is there an alternative available?

I am trying to control 25 pinball lamps using mbed.

The lamps are hooked up to 6V AC.

I have already ordered 5V DC 1A relays.

Apparently I need to connect the above relay driver to the relays and to mbed.

Please Help Cheers Dave

Findchips reports that it's available at DigiKey and Mouser. Both will happily send stuff to UK and most of the rest of the world. It's also available on Farnell UK, though AFAIR it had some issues with selling stuff to private individuals.

Well, you could roll your own.

Disadvantage: it takes 4 1/2 chips to make a 16-bit SPI relay driver. Advantage: the chips are easier to work with (through-hole), and possibly easier to source than the TPL9202.

Here's one approach. The two 74HC595 chips make a 16-bit SPI slave. You need to use a DigitalOut pin on the mbed to generate a short positive-going "latch" pulse after the SPI data transfer is complete - this pulse will transfer the serial data into the output latches of the 'HC595s. Those output signals are then buffered by the ULN2003A 50V/500mA drivers, which in turn drive the relay coils.

As you need 25 relays, you would have to build two of these. They share common mosi and sck signals, but each would need its own DigitalOut "latch" signal.

Hope that helps.

You could also use the I2C bus with 2 x PCF8575 (see http://mbed.org/cookbook/PCF8575-I2C-IO-Expander) and have 32 outputs in combination with 4 x ULN2003A 50V/500mA drivers for the relay outputs.

There is a version of ULN2003, with an spi interface available, RS, of Farnell stock it. Will look for part number when I get back to work in morning.

There is a version of ULN2003, with an spi interface available, RS, of Farnell stock it. Will look for part number when I get back to work in morning.

The RS part number is 453401 8-Bit Serial-in Latched Driver MIC5821YN,

this is a shift resistor, with shift out, so several can be cascaded, using SPI or bit bashing.

note, this should de able to directly drive relays, but I think you will need fly back diodes.

Cheers Ceri.

I use this IC which combines the serial shift register (exact same as 74HC595) with 8 high-side drivers, in a single IC: http://focus.ti.com/lit/ds/symlink/tpic6a596.pdf

I've used this in several designs and I'm extremely happy with the results. It has built-in flyback diodes, so you can connect directly to relays, lamps, etc.

They're on Digi-Key here: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-9009-5-ND

EDIT: I just noticed you are in the UK. Here's the UK version on Digi-Key: http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=UK&WT.z_homepage_link=hp_go_button&KeyWords=296-9009-5-ND&x=0&y=0

EDIT2: I also noticed this is a 5V part, whereas the mbed is 3.3V. I'll see if I can come up with a simple resistor-diode level shifter to make this work, and post a picture once complete.

Thank you for your help.

I will keep trying with the TPL9202 I have.

Let me know if you manage to get a working solution.

Cheers Dave