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Can pic drive tip41c transistor directly?

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d@nny

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can pic16f676 can drive one pair TIP41C directly at its full power?
 

alexan_e

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In general to use a transistor as a switch you have to provide to the base about 1/10 to 1/20 of the output current to drive it into saturation, so assuming that you mean 6A output you need at least 300mA current to the base and there is no way that PIC can provide that.

Alex
 

Raza

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Hi,
Can you define the Full Power needed by your circuit ?
 

d@nny

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actually the pair of tip41c is driving 3 transistors for my dc12v to 230v ac.
the emitter of tip41c is attached with the base of 3 npn transistor as darlington pair on both sides of inverter
 

vimalkhanna

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The pic 16 has output current limits of few microamps to a milliamp at the Hi o/p.As uch you need current magnifiers like a n emitter follower or darlington pairs.
When the swing is 0-hi you can use a complementary pair in class B drive .
 

bigdogguru

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The pic 16 has output current limits of few microamps to a milliamp at the Hi o/p.As uch you need current magnifiers like a n emitter follower or darlington pairs.
Actually the PIC16F family can source or sink up to 25mA per pin with a maximum of 200mA with all ports combined per device.

However, I do agree with your suggestion of the use of a Darlington Pair as a possible solution.

BigDog
 

alexan_e

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There is also a voltage drop in the outputs as the output current gets higher, this is typical for any mcu

PIC16F_VOH-IOH.gif PIC16F_VOL-IOL.gif

Alex
 

alexan_e

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The Darlington will provide a lower voltage to the base of the output transistors (the Darlington Vbe is about 2.5v) but it shouldn't be a problem.
I'm not fully aware of the described schematic.

Alex
 

d@nny

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Capture.JPG

The other 3 transistors are NEC C2750 to produce 300watt power
 

d@nny

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It is the one side of the inverter
the diode is for protection from surges but in case of presence of main power it can be use for charging the battery i mean UPS system
 

d@nny

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any suggestions?
please i am waiting for for your reply

---------- Post added at 12:36 ---------- Previous post was at 12:28 ----------

how much current and volts i require on the base of tip41 to it turn on atleast 50% power

---------- Post added at 12:37 ---------- Previous post was at 12:36 ----------

and is d313 is better in place of tip41c
 

alexan_e

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I think the Darlington would work fine.
d313 can't work either, you need much higher gain and one single transistor can't give it, the rule of thump is to use 1/10 - 1/20 of the output current so if you need nore than 200-300mA to the base of the three transistors this solution can't work, you need more gain.
 

d@nny

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I think the Darlington would work fine.
d313 can't work either, you need much higher gain and one single transistor can't give it, the rule of thump is to use 1/10 - 1/20 of the output current so if you need nore than 200-300mA to the base of the three transistors this solution can't work, you need more gain.
So what should i do?
have you any suggestions
how i can turn on tip41c to provide more gain to the three transistors
do i need one more darlington pair. i mean attach one more tip41c with other as darlington pair
but three darlington pairs would increase the dropage?

---------- Post added at 12:55 ---------- Previous post was at 12:53 ----------

sorry two darlington pairs
one tip41c and three transistors
and other tip41c with tip41c
 

alexan_e

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you can replace TIP41 with a Darlington device like TIP122 which can output a few Amperes with just 20mA to the base, it will provide about 2.5v to the base of the output transistors, they are single transistors right?
 

d@nny

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The problem is same with TIP122. Is the .1uf capacitor on protection diode disturbing?
 

alexan_e

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I don't understand what problem, you never mentioned any problem, the question of this thread was if pic16f676 can drive one pair TIP41C directly at its full power...

Alex
 

d@nny

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I don't understand what problem, you never mentioned any problem, the question of this thread was if pic16f676 can drive one pair TIP41C directly at its full power...

Alex

The output volts from inverter is 150 volts only instead of 230
but when i attached zero watt bulb having 1M resistance the voltage drops to 25 volts only
Its mean there is problem in my bising
the transformer is 9+9 volts on secondry and
0+220+240 on primary
 

alexan_e

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so now you the pic driving the TIP122 and that driving the three output transistors which are TIP41C?
Are these connected as shown in post #10 or is there any resistor?
 

d@nny

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the three output transistors are NEC C2750 to provide 300 watt output
yes the base of three output transistors ground with 2.2K transistor to the battery negative terminal
 

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