I have been trying to connect 5v supply to a L298N motor driver-IC at it’s 12V-35V input pin. Note L298N motor driver-IC is very well known to be very very robust. Findings: If I’m connecting to 7.2V supply it’s working. Is there any way to connect 5v supply? What is aimed - the goal is to have a fairly constant 5v at output pins for motors that i have connected.
I have tried to find out some things that might be of interest: I assume that the “12V-35V input pin” is the V_S pin, despite that label. Afaik there are only two supply pins on the L298-IC with the following electrical characteristics:
V_S, Supply Voltage, on pin 4, Operative Condition V_IH + 2.546V (max.: 46V)
V_SS, Logic Supply Voltage, on pin 9, typical 5V (minimal voltage.: 4.5V, max.: 7V)
with the following specs:
V_IH, Input High Voltage, ranging from 2.3V to V_SS
conclusion: the circuit works at 7.2V under the assumption that the logic inputs (if we have enabled the ports A and B as well as inputs 1 through 4) are at very close to 5V high levels. Note: here’s we have a trick that might be very important to get all to work: as noted V_S (the supply voltage) needs to be at a level of V_IH + 2.546V while V_IH could be as low as 2.3V and 2.3V + 2.546V < 5V. So if we are driving the L298’s logic inputs with a lower voltage for logic 1, i.e. closer to 2.3V high levels. What do you suggest or recommend.
Some friends allready told me to look for a more robust solution while
use even a higher supply voltage
forget the L298 and its high voltage that is needed here; drop Darlingtons and use a MOSFET H-bridge motor driver,
forget the L298 and use some nice single bipolar transistors-solutions, depending on the output current