As we all know that LED bulbs Are Sensitive to Voltage It need Either a good C.V / C.C , In this Post i am going to introduce a Precision C.C Led Driver Circuit That can Provide 0.01mA ~ 3 Amp.
Step 1: Shunt / Low Resistance Resistor
In this Project SHUNT resistor are utilized to measure flow of current. Its Value Is from 1Ohm~2.2Ohm 1% for better accuracy.
Step 2: OpAmp
OpAmp used in this project to compare 2 voltage level,( Set Voltage And Voltage produced from shunt when current is flowing). then it can switch mosfet. In this circuit i have used LM358 OpAmp you can use Low offset precision OpAmp.
Step 3: TL431
TL431( Programmable Zener )used in this project to provide Precision Reference Voltage for OpAmp, This can be found in any faulty SMPS.
Step 4: Precision 1% Resistor
You can use 5% Tolerance resistors but 1% Will give you better results.
Step 5: Mosfet
You are free to use any N-Channel Mosfet (IRFZ44N). We use Ohmic Region of mosfet Provide Variable Current.
Step 6: Clip
Clips are used to easily connect various Loads.
Step 7: Schematic Diagram / Working
Assemble all the components according to circuit diagram.
Connect P1 And P2 to your power supply.
- C1 is used to filter supply voltage.
- R3 is used to limit current for TL431.
- R1 (POT) is used to set reference voltage for TL431.
- C2,C3 are used to filter any kind of noise.
- U2(OPAMP) are used as buffer (buffer is optional in this case) you can directly connect pin 3 of TL431 to 100K pot (R2). Buffer improves stability.
- R2(100K) are used as variable voltage divider,by the use of R2 we set a reference voltage at non inverting point of U1.
- U1 is used as comparator ,we set a reference a voltage at non-inverting point, when voltage at inverting point is less than non-inverting. than output is high. In this case mosfet start conducting than voltage drop occurs at R5.
- When voltage drop is more than reference voltage than output will pulled down, it cause mosfet in off state this cycle repeats again & again.
- So output current is equal to reference voltage.
Step 8: All Done
Now Our project is ready to be checked and utilize for their work.
Step 9: Enjoy It
You can also check it on my youtube channel Channel
Make your own & let mw notify in comment section below,