• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Decoder chip with +Vcc outputs

Whimsy

New Member
I am working with a 4 to 16 decoder chip whose outputs are V- when active. This device is driving a 5V spst relay, and I am using a PNP transistor to convert V- to V+. This works, but is proving to be problematic, thus I am looking for a simpler more elegant solution. Perhaps there exits a decoder whose outputs are V+ when active, or alternatively you could suggest an IC that contains multiple PNP transistors that will eliminate the use of discreet components, resistors, and wires, and a lot of soldering.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
You could use two 74HCT237E ICs; they are 3 to 8 decoders with active high outputs and both high and low enables.

Connect the fourth input to the low enable to get outputs 0-7 on one IC and the high enable on the other for outputs 8-15.

You can use a couple of octal darlington driver ICs to connect those with the relays, eg. ULN2803; they even include the "flywheel diodes":
 

eTech

Active Member
I am working with a 4 to 16 decoder chip whose outputs are V- when active. This device is driving a 5V spst relay, and I am using a PNP transistor to convert V- to V+. This works, but is proving to be problematic, thus I am looking for a simpler more elegant solution. Perhaps there exits a decoder whose outputs are V+ when active, or alternatively you could suggest an IC that contains multiple PNP transistors that will eliminate the use of discreet components, resistors, and wires, and a lot of soldering.
You can use a CD4514B followed by a TBD62003A mosfet array driver.
 

EE World Online Articles

Loading
Top