L293E question

Go To Last Post
8 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi there,

My current design uses an L293B ic to control 4 simple resistive loads as a push-pull driver. I would like to add some protection to each output line against any short circuit. I found the L293E which is a quad push pull driver that allow the designer to add a sensing resistor to it's SENSE pins (there is one for each output).

Does anybody have the experience to tell me if I could use this ic with external resistors to set each output pin current limit to 200mA. ?

I need this before placing an order for L293E ics.

Thanks in advance.

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

According to the datasheet that is possible.
But you have to do this with an analog circuit with a few comparators. See figure 11 of the datasheet.

I don't know if you can do this with an ATmega chip with an analog input.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Use one of those Infineon BT542 drivers. They have every type of short protection ever invented.

Imagecraft compiler user

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

bobgardner wrote:
Infineon BT542 drivers

Google shows no result for that and a search in Infineon site shows no result either.
What is the exact model ?

Alex

"For every effect there is a root cause. Find and address the root cause rather than try to fix the effect, as there is no end to the latter."
Author Unknown

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

There is no result for me too, but I am very curious.

Bob, would you be able to be more specific about the driver P/N. ?

Best regards,

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi Bob,

I think that yoy are talking about the BTS.... series. Unfortunately this series has only HIGH SIDE power switches. I am searching for a push-pull switch.

Thank you,

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I guess it is BTS. But they are rugged. I blew up some solid state relays, but these things take a licking. Short protected, over voltage protected, flyback protected.

Imagecraft compiler user

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi there,

I have already bought 4 brand new pieces of the PN L293E (with SENSE pins), just to test it and see if I can stop it's functionality whenever the output current exceed a limit value.

I made the connections below:
PIN 1,2,3,4 - Non Connected
PIN 5,6 - 0V
PIN 7,8,9 - Non Connected
PIN 10 - 24Vdc
PIN 11, 12 - 5Vdc
PIN 13 - Load (400mA / 24V)
PIN 14 - sense resistor 1 Ohm (connected to 0V)
PIN 15,16 - 0V
PIN 17,18,19 - Non Connected

The ic seems that it works OK, letting me control the output by playing with the PINS 11(CE) and 12(IN).

My problem is that while measuring at PIN 14 (sense resistor = 1 Ohm), my voltmeter says 0V. While the OUTPUT - LOAD current is 400mA, I think that the voltage at the PIN 14 might be 0.4A * 1 Ohm = 0.4V.

Does anybody can help me here ?

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer