What are the part numbers of those motor drivers?
AFAIK H-bridge IC's do include flyback diodes with every MOSFET switch.
The bridge rectifier that you've quoted will be adequate for a very small, toy-car-like DC motor. It won't survive for anything over 12V and ~5-6Watt(ish) if you do a lot of braking/reversing.
I'm planning to use ST Micro's L293E, which doesn't have integrated diodes. Their L293D has, but alas no current sense pins, so I'm using the E, even though it's slightly overkill. They are indeed only small DC motors, 12-14V, max. of a few hundred milliamps.
Try some rectifier diodes in TO220 packge, used in ATX(PC) power supply secondary
(like this 1---|>--2--<|---3). some supplies also have a set of 4 rectifer diodes in single packge right after the AC mains input.
TO-220 wouldn't be suitable, as too tall. And of course mounting horizontally makes my layout problems worse.
Ordinary diodes have a higher forward voltage and are slower than Schottky diodes which could be an issue if you're doing regenerative breaking or operating at high frequencies.
Schottky diode bridges do exist. My local distributors stock them.
CDBHM220
No, not doing regenerative braking or even PWM speed control. So, given that, would non-schottky have any appreciable effect?
I see that linked example is SMD - I did find there are choices for surface-mount, but my layout is all through-hole.
Since my earlier post, I have actually found a THT schottky bridge IC: TI's UC1610N/UC2610N/UC3610N. But, there's no way in hell I'm using those as they're stupidly expensive - around £5 (~7 USD) each!