Looking for a chip that drives multiple indicator lights

sky999

Looking for a chip that drives multiple indicator lights [Copy link]

The microcontroller is 5V, but many indicator lights are 24V. Most indicator lights have a current of 10~100MA, and there are usually more than 10 of them. I often use optocouplers + transistors to switch the positive pole on and off, because the negative poles are connected together and cannot be used for switching on and off. However, there are too many discrete components, and it feels too cumbersome. Is there any IC, such as an 8-way one, that can directly use 8 5V IOs to drive 8 24v indicator lights?

maychang

"Is there any IC, such as an 8-way one, that can directly use 8 5V IOs to drive 8 24v indicator lights?"

ULN2803A, ULN2805A, 8-way Darlington.

sky999

maychang posted on 2019-7-9 08:53 "Is there any IC, such as an 8-way one, that can directly use 8 5V IOs to drive 8 24v indicator lights?" ULN2803A, ULN280 ...

Um, I know this, but it can't be used because all the negative poles are connected together.

maychang

sky999 posted on 2019-7-9 09:02 Um, I know this, but it can't be used, all the negative poles are connected together

"But it can't be used because all the negative poles are connected together."

Why must the switch be placed at the positive end of the LED? Can't the switch be placed at the positive end or the negative end of the LED to control the LED to emit light?

qwqwqw2088

24v indicator lights are generally used in electrical cabinets or PLC controls, etc.

When using a microcontroller for control, whether it is discrete components or ICs, optical coupling isolation is required.

sky999

maychang posted on 2019-7-9 09:08 "But it can't be used, all the negative poles are connected together" Why must the switch be placed on the positive end of the light-emitting tube? The switch is placed on the positive end of the light-emitting tube...

Because many indicator lights and some components share the same GND, they are connected together internally, leaving only the positive terminal