ULN2003 principle and application

uln2003 application circuit

The ULN2003 is a high voltage, high current Darlington display and consists of seven silicon NPN Darlington tubes.

The circuit features are as follows:

Each pair of Darlington ULN2003 are connected in series with a base resistance of 2.7K, 5V at the operating voltage it can with the TTL and CMOS circuits

Directly connected, you can directly deal with the original need for standard logic buffer to deal with the data.

ULN2003 high operating voltage, operating current, sinking current up to 500mA, and can withstand 50V in the off-state voltage, the output also

Can operate at high load currents in parallel.

ULN2003 DIP-16 or SOP-16 plastic package.

The design uses GALl6V8 as a ring pulse distributor, ULN2003 (domestic model 5G1413) is a seven Darlington drive array, is an open collector (OC) output inverter, the maximum drive current up to 500mA. The usual application is to load the stepper motor connected to VDD (12V), the other end connected to the output pin, such as 16 feet. In order to prevent the program from entering the dead loop, an external hardware watchdog timer MAX813L is added, and its internal watchdog timer monitors UP / UC's work. If its operation is not detected within 1.6s, the internal timer will keep watchdog output WDO low and WDO will remain low until UP / UC is detected at WDI. Connecting WR and WDO can reset the watchdog timeout. Using two ULN2003 were driven X, Y direction of the stepper motor. Specific hardware circuit shown in Figure 1.

Relevant ULN2003 series products

 Author：Brittany Antonia （The author of article owns the copyright.）