two transistor driver - Electronic Circuits Projects Diagrams Free

adam2 · 4th December 2004, 10:26 PM

Hello,

I am going to use the output of the following circuit to drive a 7-segment LED display:
http://www.adwojnowski.webpark.pl/leddriver.gif

I am going to need 5 displays (and 5 such circuits). Is there an IC that contains the elements that I need (shown in the picture)?

Thanks,
Adam

Roff · 6th December 2004, 07:06 PM

Well, there might be something that will work, depending on a few things.
What is the positive supply voltage? What are you driving the input with? How much current does the PNP have to pass?

hotwaterwizard · 7th December 2004, 04:33 AM

Maybe a Darlington.

adam2 · 8th December 2004, 08:39 PM

> Well, there might be something that will work, depending on
> a few things.
Here come the answers:

> What is the positive supply voltage?
5 V (3.3V is also available)

> What are you driving the input with?
Xilinx FPGA (probably Xilinx 4000)

> How much current does the PNP have to pass?
A few mA. It is going to drive a LED

Roff · 9th December 2004, 05:45 PM

Well, the 74LVC4245A looks like it will work provided you keep total device current below 100ma. This would mean you would probably want to limit LED current to about 18ma each. The package may be larger than you hoped for.

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4th December 2004, 10:26 PM	#1
adam2	two transistor driver Hello, I am going to use the output of the following circuit to drive a 7-segment LED display: http://www.adwojnowski.webpark.pl/leddriver.gif I am going to need 5 displays (and 5 such circuits). Is there an IC that contains the elements that I need (shown in the picture)? Thanks, Adam Attached Thumbnails

6th December 2004, 07:06 PM	#2
Roff	Well, there might be something that will work, depending on a few things. What is the positive supply voltage? What are you driving the input with? How much current does the PNP have to pass?

8th December 2004, 08:39 PM	#4
adam2	> Well, there might be something that will work, depending on > a few things. Here come the answers: > What is the positive supply voltage? 5 V (3.3V is also available) > What are you driving the input with? Xilinx FPGA (probably Xilinx 4000) > How much current does the PNP have to pass? A few mA. It is going to drive a LED

9th December 2004, 05:45 PM	#5
Roff	Well, the 74LVC4245A looks like it will work provided you keep total device current below 100ma. This would mean you would probably want to limit LED current to about 18ma each. The package may be larger than you hoped for.