Troubleshooting my ULN2003A Chip Setup

In summary, the conversation discusses the use of ULN2003A chips for powering a stepper motor. The individual is facing difficulties in understanding how to use the chips and is not sure if their setup is correct. They have connected pin 8 to gnd and supplied pin 1 with 5 VCC. The voltage drop across the resistor is measured to be around 5 volts. The datasheet for the chip is provided for reference, which states that the output voltage is limited to the supply voltage. The individual is expecting a stepped-up voltage of ~50V, but this chip does not have that capability. It is simply a darlington transistor array with a flyback protection circuit to protect against inductive loads.
  • #1
jesuslovesu
198
0
I recently purchased a few ULN2003A chips with the goal of eventually powering a stepper motor. So far I'm just testing out the chips, but I've run into a bit of a roadblock. I'm not quite sure how to use the chips.

My setup is as follows:
I have connected pin 8 (gnd) to gnd. I have supplied pin 1 (in 1) with 5 VCC.
Using a resistor (because I don't have any LEDs) I have supplied one lead with 5VCC and the other lead to pin 16 (out 1). I then proceed to measure the voltage drop across the resistor and I get about 5 volts.

Since I'm supplying a constant voltage to pin 1, shouldn't it be stepped up to ~50V (the maximum)? Is my understanding of the chip's operation incorrect? Or do I just have the setup wrong?

The datasheet is available here [link]http://www.ortodoxism.ro/datasheets/SGSThomsonMicroelectronics/mXtyyvx.pdf[/link]
 
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  • #2
The output voltage is limited to the supply voltage.
You should get slightly less then 5v with a 5v supply.
 
  • #3
The 2003 is simply a darlington transistor array with all of the emitters connected together to one pin of the IC which is usually grounded. This IC does NOT step up voltage if that is what you are after. I believe the collector of each transistor is tied to the high voltage lead through a diode which forms a flyback protection circuit to protect the transistors against inductive loads.
 

Related to Troubleshooting my ULN2003A Chip Setup

1. How do I know if my ULN2003A chip is working properly?

The best way to determine if your ULN2003A chip is functioning correctly is to test it with a multimeter. Check for proper voltage levels and continuity between pins. You can also check for any signs of physical damage or overheating.

2. Why am I not getting any output from my ULN2003A chip?

There could be several reasons for this. First, make sure that your power supply is providing the correct voltage to the chip. Also, check your connections and make sure they are secure. If everything seems to be in order, there may be an issue with the chip itself and it may need to be replaced.

3. Can I use the ULN2003A chip with any microcontroller?

Yes, the ULN2003A chip is compatible with most microcontrollers. Just make sure to check the datasheet for your specific microcontroller to ensure compatibility and follow the recommended circuit design.

4. How do I troubleshoot if my ULN2003A chip is overheating?

If your ULN2003A chip is getting too hot, it could be a sign of a short circuit or incorrect wiring. Start by checking your connections and make sure they are correct. If everything seems to be in order, try using a heat sink or reducing the load on the chip by using an external power supply.

5. What is the maximum current that the ULN2003A chip can handle?

The ULN2003A chip can handle a maximum current of 500mA per channel, with a total current of 1A for all channels combined. It is important to not exceed these limits as it can damage the chip.

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