Can we parallel H-bridge input and output for increse current?
For specific I select 2 case
For L298N as shown in datasheet suggested to parallel chanel to increse current. For TB6612FNG It have designed dead time. If we can or we already did it. The question are
If this is about parallel controlled IC's it may not work unless there is a way to synchronize them. If the datasheets do not specify being able to sync with other IC's then you cannot do so.
Individual MOSFETs with same part number, and hopefully same batch number will track each other very well. If there is a source resistor used to sense current all parallel MOSFETs need to use the same current sensor. Internally a MOSFET is an array of parallel transistors used to build up the current rating, so parallel MOSFETs share loading very well.
As for preventing "shoot-through" the PWM controller and design topology help insure there is dead-time so that 1 MOSFET is switched OFF before the other MOSFET is turned ON.
It is bad practice to blindly parallel drivers without knowing how to estimate the power dissipation and heat rise.
Generally you choose drivers and heatsinks so that they are capable of driving the DCR coil resistance for surge starts with much less voltage drop than the DCR. Your MOSFET H bridge specs are:
Therefore the motor DCR must be matched to the driver. 3.2A peak implies a ratio of I=Vbat/(2Ron+DCR). Since there are two FETs active , it is 2Ron.
If you need more current, consider a better bridge driver instead. 6644 family and up instead of 6612
Multiple devices in parallel simply give you more of the same problem you already have with an H-bridge - namely that you need to allow enough dead time for one side to turn off fully before you turn on the other side. With a single device, it can manage its own dead time to some extent. With multiple devices, your controlling micro will need to handle it. Use the datasheets to find the worst-case dead time required for your device, then double it to allow for tolerances between devices, and use that time in your micro.
Then we get onto device types. BJTs are vulnerable to thermal runaway, so in general they should not be used in parallel unless the device has some kind of additional circuitry to prevent this. MOSFETs do not generally suffer from this, so they are safer to use in parallel. However MOSFETs do still have the disadvantage that since their on-resistance will not be exactly the same, one device will still have more current through it than the other. You'll need to use the max/min on-resistance specs to work out how bad the balance between devices could be.
