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Ne555 and IR2103 dimmer

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aqustic206

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I want to dimmer a lamp (40 or 50 watt) with ne555 with p channel
But p channel mosfet is burning.So I am going to try with IR2103 and IRFZ44.. IRFZ44 like p channel with IR2103
Do you think the circuit is true?Please help me.
And I have only 12v adaptor.


**broken link removed**
 

I want to dimmer a lamp (40 or 50 watt) with ne555 with p channel
But p channel mosfet is burning.So I am going to try with IR2103 and IRFZ44.. IRFZ44 like p channel with IR2103
Do you think the circuit is true?Please help me.
And I have only 12v adaptor.
Click to expand...
Hi aqustic !
I've a better suggestion for you !
Use a 555 directly to drive an n mosfet which it's source has been grounded and then put your lamp into the drain and tie it's another head to the VDC !
BTW : you'd better to use a totem pole circuit to drive your mosfet , for this method . and an LC filter in path of your lamp will be required for better responsibility of your circuit . if you do something like what i told , i guarantee you won't have any problem ! and of course it will be cheaper !
Best Wishes
Goldsmith
 

For a lamp, there's no need to drive the MOSFET in high-side configuration.
At the output of 555, use a totem-pole driver which drives the IRFZ44. The IRFZ44 has its source connected to ground. One end of the lamp connects to the MOSFET drain. The other connects to +12V through an inductor. Connect a capacitor across the lamp.

With just PWM, without filtering, you'll notice that the lamp flickers. To avoid this, you use the LC filter which gives a DC output whose value is given by the duty cycle of the PWM set by 555.

Hope this helps.
Tahmid.
 

with 12v connected to 555 it can drive Irfz44 directly there is no need for a driver for a load of mere 50W. you connect gate to pin 3 with a resistor bettween 60 to 70 ohms
 

I am going to use in my car's lamp
.So one of wire of lamp is ground.That I am trying only + wire of lamp.

Please give me circuit please here.
 

I am going to use in my car's lamp
.So one of wire of lamp is ground.That I am trying only + wire of lamp.

Please give me circuit please here.
Click to expand...
Hi again
is that mean that you don't have access to the ground side ?
 

remember connect drain to bulb and other end of bulb to +ve not -ve

- - - Updated - - -

source to ground
 

I am going to use this circuit in my car for car's lamps.
And I have not access to the - side. I am use only +side of lamps

So I used p channel IRF9540.but mosfet is burning.:(

I am very sorry.I need to take circuit
 

Can you show the circuit using the P-channel MOSFET? Maybe we can find the fault in it and suggest the solution(s). High side drive for lighting a lamp just seems like overkill.
 

for high side there is no other way but to use ir2103
 

As for the circuit shown in post #1, it seems okay. Add a 1k resistor between the MOSFET gate and source. Connect a capacitor (100uF - 470uF) from IR2103 VCC to COM. Use a ceramic capacitor for C12. Connect pin 3 (LIN) to ground.

- - - Updated - - -

aqustic206 said:
I am used this driver.The mosfet is p channel IRF9540.And İt is burning
**broken link removed**
Click to expand...

Connect a resistor between the collector of the NPN transistor and the gate of the MOSFET.

Besides that, I don't see a reason for it burning. Even if the MOSFET stays on, it shouldn't burn. The lamp should just be on. Did you check the power rating of the lamp properly? Did you mount the MOSFET on a heatsink?
 

No I have not heatsink

And is the collector resistor 1k enough?

İs there a way without circuit?If ı use IR2103, am ı need heatshink?Because ı think ıf I use IR2103
 

aqustic206 said:
No I have not heatsink

And is the collector resistor 1k enough?
Click to expand...

Are you referring to the circuit in post #11? The collector resistor must be there. Decrease its value. But, an additional resistor should be connected between the collector of the transistor and the gate of the MOSFET.

Also, you must use heatsink. The MOSFET probably burnt due to overheating. The RDS(on) of the P-channel MOSFET is quite high.

İs there a way without circuit?If ı use IR2103, am ı need heatshink?Because ı think ıf I use IR2103
Click to expand...

The IRFZ44 has a lower RDS(on). So, heat dissipation will be lower. However, don't completely eliminate the use of heatsink. Use a small heatsink.
 

Tahmid is the 10k from collecter to + too high value
 

The frequency is around 150Hz. But still, 10k is a little too high. A totem pole driver could be used there, such as the one shown below.

4035003600_1353000198.png
 
Last edited:

Tahmid for a drive frequency of 50Khz can you suggest a reasonably priced Q3 and Q4 (better if available in a combined package)
 

For higher frequencies, it's better to use dedicated driver chips such as TC426, TC427, TC428, etc. They are quite cheap, easy to use and quite reliable.
 
tpetar, your circuit is okay, but the OP has mentioned that he requires a circuit where the switch is configured as high-side switch.
 

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