# L293, L298 and SN754410 H-bridge drivers on low voltage power supply

This question is about the following three integrated H-bridge drivers: -

• L293 or L293D (D = protection diodes added)
• SN754410 (protection diodes included)
• L298 (no protection diodes)

Time after time the same question keeps coming up - someone is using one of these devices (on a low voltage, usually around 6V or less) and they are just not performing adequately. The reasons are listed further below but my question is this: -

What H-bridge drivers are preferred when controlling a low-voltage motor?


# Information

The L293 and the SN754410 are nearly identical and crucially, if you try and control a 1 amp load, you are faced with dismal performance: -

The tables tell you (typical conditions) that the upper transistor drops (loses) about 1.4 volts when driving a 1A load and, the lower transistor drops (loses) about 1.2 volts when driving a 1A load. The upshot is that if you have a 6V, 1A motor and 6V battery, don't expect to see more than 3.4 volts across the motor: -

$V_{OUT} = 6V - (1.4V + 1.2V) = 3.4V$

Worst case scenario is you might only see 2.4 volts across it.

What about the L298? It's got a nice big heat-sink whereas the L293 and SN754410 are regular-looking chips. Here's what the volt drop (losses) look like: -

It's the same story - for a 1A load, you can expect to lose up to 3.2 volts and, what you thought might be 6V across your motor, is at best 4.2 volts and at worst only 2.8 volts.

Clearly none of the devices listed are suitable for low voltage applications where the motor might be expected to draw in excess of 0.5 amps.

• I have been using both the L298 and L293D. I would recommend the L298 over L293D. Practically speaking, the voltage drop was never below 1v for 1 Amp 6 volts motor. While on the other hand, the L293D had way worse voltage drop. – Adel Bibi Apr 30 '14 at 21:47
• @AdelBibi in a full H bridge configuration, the spec says that the minimum volt-drop is 1.80 volts - I don't see how you can say it was below 1 volt unless you mean this for a half-bridge configuration? – Andy aka Apr 30 '14 at 21:52
• I have the full bridge. It might be because I'm using a module that might have a certain ciruitry that helps improving the voltage drop. I'm using one similar to this: ebay.com/itm/… – Adel Bibi Apr 30 '14 at 21:56
• It seems to me that this is a shopping question and should be considered off-topic. The question pretty clearly asks about "preferred" drivers, which are commercial products, rather than for generic design solutions to the problem. I'm a little nervous about voting to close a question asked by someone with that much rep, but let's see what the community thinks. – Joe Hass May 1 '14 at 11:01
• Please see the discussion at meta.electronics.stackexchange.com/questions/3439/… regarding a previous instance of someone asking a question and then answering with a recommendation of a specific commercial product. – Joe Hass May 1 '14 at 11:08

For low voltages, it seems like the DRV8837 is pretty good: -

With an 800mA load, the volt drop is: -

$I_O\cdot R_{OS(ON)}$ = 800mA x 0.33 ohms = 0.264 volts. At this current, the power dissipation will be 0.8 x 0.8 x 0.33 watts = 211 mW.

Compare this with the L293 power dissipation at about 800mA - maybe about 3V is lost giving rise to a power dissipation of 2.4 watts.

The VNH5200AS-E from ST is also pretty good and is intended for supplies as low as 5.5V up to 18V: -

Also, another offering from ST is the VN5770AKP-E. It can be configured as separate top-side and low-side MOSFETs (including drivers) or just wired as a H bridge.

There is also the MC33887 from Freescale (formerly Motorola): -

It has on resistances in the low hundreds of milli ohms too.

• The DRV8833 and DRV8835 are 2-channel (dual H-bridge) alternatives that are otherwise pretty comparable. – kwc May 1 '14 at 4:22
• @Andy I think we are on very dangerous ground here. You asked a question and then gave your own answer, which is a recommendation for a specific commercial product. There is some precedent here that this is not appropriate. I have no doubt that this is useful information, but you open the floodgates to stealth advertising and unethical promotion. – Joe Hass May 1 '14 at 11:05
• @JoeHass I do see your point and the fact that you are now saying this means it is likely that this won't happen due to the collective diligence of members. I'll try and add a non-TI product to this answer to level things up a bit. I was rather hoping for other answers by now - surely there must be other offerings suppliers other than TI? – Andy aka May 1 '14 at 11:08
• @JoeHass I've aded a couple of devices from ST and a device from Freescale to even things up a bit. I'm still hoping for more answers though. – Andy aka May 1 '14 at 12:12
• @Andyaka You've requested more manufacturers - Is Allegro A4952, A4953 too complex to suggest for a general brushed motor driver? DMOS switches of about 1 ohm. Thermal load can actually handle 1A motor current. A4950 is a bit more robust. – glen_geek Jan 1 '17 at 20:07

IR2210 is most famour MOSFET driver used in power electronics circuits and H bridge designin g. You can take a look a complete guide on how to make H bridge using IR2210. He explains every thing very well http://microcontrollerslab.com/use-mosfet-driver-1r2110/ http://microcontrollerslab.com/how-to-make-h-bridge-using-ir2110/

• There is no such driver that I can find. If you meant the IR2110 then it is not a low voltage driver (minimum recommended voltage supply is 10V) – Andy aka May 20 '15 at 10:40