As a part of my new project I need to redesign UV LED driving circuit. Here I am using TI’s AM335x processor and using the SPI I have connected one DAC – LTC2668-12. The DAC output is going to the UV LED - NSHU591C. The specification of UV LED is given below.
(Highlighted one is using).
The DAC output (set to 0.068V) is connected to OpAmp (OPA4140) circuit and it is used for constant current sourcing (correct me if my understanding is wrong). The circuit is given below.
The UV LED’s cathode is connected to the non-inverting terminal of the amplifier B for current measuring.
DAC_VOUT1 – DAC channel 1 output.
LED1_A – UV LED Anode
LED1_K – UV LED Cathode
I have some queries on this.
- Currently in the circuit a 12-bit 16channel DAC is using, I have a plan to replace the DAC with TI’s DAC7564. Will it compatible with the above OpAmp circuit or suggest some other DAC having 4 channel and better accuracy.
- Is there any other method to drive the UV LED with constant current.