I am using an LM2576-Adj regulator to eventually provide a constant current supply at 2.16amps. The LM2576 is capable of running at 3 A and I am able to adjust the current through a 6 ohm load to the required 2.16 A. I need to be able to turn the regulator off and there is a pin (pin No 5) to accomplish this. With pin 5 grounded it runs quite happily at 2.16 A but if I take pin 5 high then it does not cut off the regulator completely but leaves a residual 0.27 A current.
Does anyone have any ideas why this should be happening?
Below is an image of the circuit I am using.
I forgot to say there are some alterations to the above circuit.
1) input is 24V regulated
2) D1 is a 5 A Schottky diode as is an additional 5 A diode placed between the positive side of the 1000uF capacitor and the top end of R2
3) I have used a 150uH torroidal inductance.
4) The output voltage measures 13.09 V
5) R1 is still 1.8K but R2 consists of a 10K fixed resistor in series with a 20K trimmer pot which was adjusted to provide the 2.16 A output current.
Does anyone have any ideas why this should be happening?
Below is an image of the circuit I am using.
I forgot to say there are some alterations to the above circuit.
1) input is 24V regulated
2) D1 is a 5 A Schottky diode as is an additional 5 A diode placed between the positive side of the 1000uF capacitor and the top end of R2
3) I have used a 150uH torroidal inductance.
4) The output voltage measures 13.09 V
5) R1 is still 1.8K but R2 consists of a 10K fixed resistor in series with a 20K trimmer pot which was adjusted to provide the 2.16 A output current.