Doh, my bad on the sidedness. My favourite high side device is the VN340.=20 https://www.st.com/en/power-management/vn340sp-e.html Four channels, 0.7A or 1A per channel depending where you read. Overkill, b= ut=20 easy to use. See VN330, VNQ660 & VNQ690 for other currents. Not current=20 regulating, just temp and overload protected etc, so would need resistors..= Reverse=20 supply protection added by a small signal diode, see notes in 660/690 data-= sheet.=20 Don't buy from Ali-Express (bought 30 to try them out... no function whatso= ever, no=20 refund whatsoever). If you could mux the 4 x digits with your proposed driver board you'd only = need 2 x=20 VN340s to drive the 7 segments, plus a discrete NPN or N-channel transistor= for=20 low side switching each digit. The 2 x LED's for the colon could perhaps be= driven=20 directly from the 8th channel and GND if decimal points not required, or tr= eat the=20 colon as a 5th digit and mux with the rest, or perhaps hard-wire the colon = on all the=20 time. The VN340 has significant switching delays... but a mux rate of some hundre= ds of=20 Hz or perhaps a few kHz should be achievable/acceptable. Brent. On 26 Feb 2019 at 17:48, Dwayne Reid wrote: > Hi there, Brent. >=20 > Unfortunately, this appears to be a sinking driver rather than=20 > sourcing. But that does remind me to check what other devices that > TI might have available. >=20 > Many thanks! >=20 > dwayne >=20 >=20 > At 03:35 PM 2/26/2019, Brent Brown wrote: > >The TLC5940 may be worth looking at. 16-Channel LED Driver With > DOT > >Correction and Grayscale PWM Control. Serial data interface (which > I=20 > >guess is SPI > >like). I've designed them into a PCB before on a customers request, > >but I didn't > >have to do the programming. > > > >http://www.ti.com/lit/ds/symlink/tlc5940.pdf > > > >On 26 Feb 2019 at 12:19, Dwayne Reid wrote: > > > > > Good day to all > > > > > > Several years ago, we purchased the assets of a LED clock > > > manufacturer in our town. We wound up with several hundred > 4-digit > > > red LED displays used for clocks installed in schools and > > > hospitals. Part number SK-2545D-24 > > > > > > Nice displays: digits are about 2-3/8" tall and > > > decently-bright. That's the good. The bad is that these are > > > direct-drive displays: no multiplexing **AND** they are > > > common-cathode. This last really sucks. > > > > > > These are RED displays. Each segment has 3- red LEDs in series, > the > > > other dots are all single LED, including two individual LEDs for > the > > > colon. > > > > > > So: I'm looking for recommendations for a high-side LED > display > > > driver chip. I need something like 35 channels, preferably > with > > > constant-current output. The segments having three LEDs means > that > > > the driver needs to operate from at least 10 Vdc, preferably > 12 > > > Vdc. Assume around 20mA or less per LED or LED group. Serial > SPI > > > preferred but would accept I2C if that was the only option. > > > > > > Idea is to make a driver board for these displays that also > holds a > > > PIC and power supply. We can then either use these displays / > > > driver > > > board for our own projects or flog them to willing buyers. > > > > > > I'd ask on electronics.stackexchange.com but product > recommendations > > > are specifically prohibited on that site. > > > > > > Any suggestions greatly appreciated. > > > > > > Many thanks! > > > > > > dwayne >=20 >=20 > --=20 > Dwayne Reid > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > 780-489-3199 voice 780-487-6397 fax 888-489-3199 Toll Free > www.trinity-electronics.com > Custom Electronics Design and Manufacturing >=20 > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .