On using the SN754410: Some people use the SN754410 motor driver chip because it is pin-compatible, has output diodes and can provide 1A per motor, 2A peak. After careful reading of the datasheet and discussion with TI tech support and power engineers it appears that the output diodes were designed for ESD protection only and that using them as kickback-protection is a hack and not guaranteed for performance. For that reason the kit does not come with the SN754410 and instead uses the L293D with integrated kickback-protection diodes. If you're willing to risk it, and need the extra currrent, feel free to buy SN754410's and replace the provided chips
What if I add my own flyback diodes (1N4007), would it then be perfectly safe to use the SN754410?
But is it possible to add these diodes to the circuit and still maintain a reversible motor?
On using the SN754410: Some people use the SN754410 motor driver chip because it is pin-compatible, has output diodes and can provide 1A per motor, 2A peak. After careful reading of the datasheet and discussion with TI tech support and power engineers it appears that the output diodes were designed for ESD protection only and that using them as kickback-protection is a hack and not guaranteed for performance. For that reason the kit does not come with the SN754410 and instead uses the L293D with integrated kickback-protection diodes. If you're willing to risk it, and need the extra currrent, feel free to buy SN754410's and replace the provided chips
What if I add my own flyback diodes (1N4007), would it then be perfectly safe to use the SN754410?
But is it possible to add these diodes to the circuit and still maintain a reversible motor?
Where O1 and O2 are the outputs from the h-bridge, D1-D4 are the diodes, GND is ground, and +VS is the DC supply for the motor.
The only thing about the datasheet for the SN754410 is that it doesn't say whether to use high-speed Shottky diodes or not; the 1N4007 is not such a diode. It might work OK - I'm not sure (go for Shottkys if you can for this app - they don't really cost all that much more).
On using the SN754410: Some people use the SN754410 motor driver chip because it is pin-compatible, has output diodes and can provide 1A per motor, 2A peak. After careful reading of the datasheet and discussion with TI tech support and power engineers it appears that the output diodes were designed for ESD protection only and that using them as kickback-protection is a hack and not guaranteed for performance. For that reason the kit does not come with the SN754410 and instead uses the L293D with integrated kickback-protection diodes. If you're willing to risk it, and need the extra currrent, feel free to buy SN754410's and replace the provided chips
What if I add my own flyback diodes (1N4007), would it then be perfectly safe to use the SN754410?
But is it possible to add these diodes to the circuit and still maintain a reversible motor?
Where O1 and O2 are the outputs from the h-bridge, D1-D4 are the diodes, GND is ground, and +VS is the DC supply for the motor.
The only thing about the datasheet for the SN754410 is that it doesn't say whether to use high-speed Shottky diodes or not; the 1N4007 is not such a diode. It might work OK - I'm not sure (go for Shottkys if you can for this app - they don't really cost all that much more).
Thanks for this info. I'm adding it in now, can you take a look at this drawing and make sure I've got the diodes oriented right, going to ground or voltage at the right places...