Techvision srilanka

Brief Circuit explanation:

This is an implementation of the L298 to drive motors and inductive loads up to 4A continuously. Initially the L298 contains 2 separate channels, each one capable of driving 2A loads. Connecting them in parallel as in the schematic makes a single 4A driver.

The two wire connections W1 and W2 are to control the direction of the motor according to that table:

Signal on W1 and W2	result/action
10	Motor turns clockwise
01	Motor turns anticlockwise
11	Motor breaks
00	Motor is free

The 2 transistors Q1 and Q2 act as an OR gate enabling the L298 if any of the two signals W1 or W2 are high. If both W1 and W2 are low (logic 0), the driver is disabled and provides a high impedance on its output, causing an eventually connected motor to move freely with its inertia.


C1 and C2 are 10 nF decoupling capacitors.

D1 to D4 are flyback diodes. Their forward current should correspond with the the expected load.

The two leads of the motor are directly connected to J1. The circuit can be powered with 9 to 35V Here is an implementation of this circuit on a PCB. This an actual picture of the motor drivers we used in the ROBOCON 2007 competition. Notice how the heatsink is firmly attached to the driver. this protects the IC from eventually burning-up from stall currents.

Download the zip file for this project containing the full schematic, PCB designs and datasheet of the L298 IC. [note: i use ExpressPCB(FREEWARE) to design the schematics and the PCB]