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Bruce Grenade
03/25/06 21:36
Read: 554 times

#113112 - Switching an IC off using BJT?

I wish to switch off (less than a couple uA) an IC when not in use. I am currently using a MOSFET, but it's expensive for my design. I have never seen a BJT used for this purpose before. Is there any reason I cannot do so? See the circuit Below:

Basically, Vcc is 15VDC. The IC is a MOSFET driver that switches a motor at high speed. I believe the driver uses about 10mA during normal use. The inputs (DRV1 and DRV2) don't matter to my question. ON is a +10VDC drive and OFF when near 0V. The BJT can be any transistor, but operation is fairly infrequent (once every few hours). I think something like a 2n3904 can supply way more than 10mA that I need.

Can a general purpose BJT be used without adding noise or other negative effects? I know that the Vcc voltage level may decrease a little to the IC, but this is OK.

Thanks for your help

List of 7 messages in thread
Switching an IC off using BJT?      Bruce Grenade      03/25/06 21:36      
   Try using a PNP        Russell Bull      03/26/06 00:49      
   Good Good      Bruce Grenade      03/26/06 09:16      
      "expensive" is relative      Erik Malund      03/26/06 10:55      
         Of course      Bruce Grenade      03/26/06 11:47      
   Using a MOSFET makes sense        Kai Klaas      03/26/06 16:28      
      Good Info      Bruce Grenade      03/26/06 17:03      

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