A logic gate chip with 1 ea XOR and 2 ea AND gates?

[jellis00]

http://www.mcmanis.com/chuck/robotic...t-circuit.html
http://www.cadvision.com/blanchas/hexfet/np-s.htm
http://www.4qdtec.com/h.html
The simplest 4 transistor h bridge:
http://library.solarbotics.net/circu...arHbridge.html

Joe: I studied the H-Bridge circuit and I can see now why it is probably the preferred choice for microcontroller use with motor control, and I presume it can be applied in same manner for controller of latching solenoids. Therefore, I have redone our design as shown in the attached schematic, in which we propose to use a ROHM H-Bridge IC model BD6211 or BD6221, depending on what battery voltage we select for solenoid control (see http://www.rohm.com/products/databoo...x_series-e.pdf for data sheet). This IC can be purchased for $1.50 USD at Mouser and greatly reduces the cost and simplifies the circuit layout as compared to using relays. What is your opinion of this schematic?....will it work to control the latching solenoid without fear of "shoot through" during startup of the MCU while it is being initialized and the MCU pin logics are not yet stabilized? At this point that is my only concern about using the H-bridge for latching solenoid control.
Thanks so much for this tip!

[bogdan]

..the clamp diodes are missing...

I think is easy with L293D (internal clamp diodes)...if you combine the channels you have Peak Output Current=1.2A (check the specs of the solenoid)

If you need more current use TLE 5205-2 (peak=6A)

Both of the items should be at mouser.com

...please check also this tutorial to understand better the h-bridge circuit http://www.robotroom.com/HBridge.html

[jellis00]

..the clamp diodes are missing...

I think is easy with L293D (internal clamp diodes)...if you combine the channels you have Peak Output Current=1.2A (check the specs of the solenoid)
]

Granted I forgot the external clamp diodes, but I can't see why you think using the L293D is an advantage over the Rohm BD62x1. Here are compairsons that appear to favor the BD62x1:

Operating range: BD62x1 will run with Vss 3 to 36 v; L293D is 4.5 to 36. This is important to me since my board supply is 3.95 vdc (3 ea AA NiMH batteries);

Quantity 1 price at Mouser: BD62x1 = $1.50; L293D = $5.12....even adding the 4 ea clamp diiodes (1N4001??) BD62x1 approach is a lot cheaper;

Low Stanby current: BD62x1 has standby mode = 10 microAmps; L293D has quiescent current total (Vss + Vx) of at least 18 milliAmps dey pending on logic setting.....this is too high for battery operation.

Based on above comparison I wouldl really appreciate your opinon as to why the L293D is preferable. ???

[jellis00]

Granted I forgot the external clamp diodes, but I can't see why you think using the L293D is an advantage over the Rohm BD62x1. Here are compairsons that appear to favor the BD62x1:

???

Taking a closer look at the Rohm data sheets for their BD622x chips, it appears they also have internal clamp diodes, making it a further advantage for the BD622x1 over the L293D. The chip diagram from data sheet is in the attached image. Am I mis-interpreting this image??

[Archangel]

Sorry for the delay, my ISP is sooooo lame!
Lots of HBridge chips out there, allegro makes a bunch of them, It trumps relays due to cost, reliability, size and they look better too even discrete transistors are still cheaper, smaller, and more reliable, though mosfets might be better than junction types.