ULN2003: driver for electric motors

ULN2003

In this post, we will examine the pinout, function, and connection schematics of the ULN2003, as well as an application example, in addition to its function as a relay controller. In this way we add yet another new component to our long list of devices presented.

What do you need a ULN2003 for?

ULN2003 MODULE

A single control unit has a set of control functions that control the voltage levels at their inputs and outputs, as well as timers, PWM, interrupts, and switching methods. These control functions allow us to produce multiple functions without interfering with the entire controller circuit. To produce multiple operations, a simple controller and processor were used. The problem was to minimize the circuit of high voltage direct current equipment.

The dc motors High voltage had been widely used due to its energy efficiency. The problem was how to control and minimize the circuit of high voltage DC equipment. To control high-voltage DC loads up to 50 V and 500 mA, a logic circuit with a Darlington transistor (NPN) was used. This circuit was only capable of controlling a single load. To solve this problem, ULN2003 ICs were introduced.

What is the ULN2003?

PINOUT AND DATA SHEET

This IC has a wide selection of applications. Can control up to seven loads at once using seven Darlington transistors. The ULN2003 is available in various package types such as SOP, PDIP, TSSOP, and SOIC. The ULN2003 contains seven output pins that can be used independently of the input pins to create a transistor circuit. The IC is compatible with any circuit without taking up much space.

Since the output voltage is independent of the input voltage, it can be used in any circuit such as a microcontroller or microprocessor. The voltage range for the loads is 50V, but the current range is 500mA. This range can be extended if multiple output pins are used. The ULN2003 is protected against counter frequencies and has an internal protection system against recoil to protect the device.

Characteristics of the ULN2003

As for the the most outstanding features of the ULN2003 are:

  • It can handle voltages up to 50V (there are versions that can tolerate up to 100V).
  • The current that can be handled is up to 500mA for each input.
  • Includes an internal clap diode to protect the device.
  • It also has an internal flyback system protection and one pin can be used for inductive charging.
  • It can be perfectly integrated with microcontrollers and Arduino-type boards.
  • It is compatible with TTL logic and 5v CMOS.
  • The ULN2003 chip can come in different packages like SOP, TSSOP, PDIP, etc.
  • Generally, on the market it comes with other extra elements mounted on a module to facilitate connection.

Pinout

The DIP chip of the ULN2003 is made up of 16 pins. These are a series of inputs and outputs that I detail here:

  1. Input 1: This pin is used to control the corresponding output (output 1). If it's high (5v) then there will be an output, otherwise there won't be.
  2. Input 2: Same as above, but affects output 2.
  3. Input 3: the same, in this case for output 3.
  4. Input 4: same, for output 4.
  5. Input 5: ditto, in this case for output 5.
  6. Input 6: as above, but for output 6.
  7. Input 8: the same but applied to output 7.
  8. GND: This pin number 8 is used for ground and will be connected to the power supply.
  9. COM: This pin can serve multiple functions. It is generally used as a test pin to turn on all outputs. It can also be used as an inductive load.
  10. Output 7: it is the output controlled by input 7 and any 50V and 500mA load can be connected.
  11. Output 6: Same as above, but affected by input 6.
  12. Output 5: same, but the one corresponding to input 5.
  13. Output 4: the same as above, but is controlled by input 4.
  14. Output 3: exactly the same, but it is the one corresponding to input 3.
  15. Output 2: as above, but corresponds to input 2.
  16. Output 1: controlled by input 1, but with the same characteristics as the previous ones.

As you can see, the inputs and outputs are reversed in order, so be careful with this. For more information, you can download the datasheet manufacturer from which you purchased the ULN2003 chip or module.

Applications

Some of the most outstanding applications of this chip can be:

  • Controller of up to 7 relays or stepper motors.
  • Control inductive loads.
  • Control high load LED lights.
  • Be used as a logic buffer in most digital electronic circuits.
  • etc.

How the ULN2003 is used

Where to buy

If you need purchase one of these ULN2003, you have several options, either buy it in a module or buy the chip alone. They also sell kits with motors and connectors needed to get started. The choice is yours. In any case, they are quite cheap. Here are some recommendations:


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