Driving a ring of LEDs in strobe mode

[graemeian]

I want to drive a ring of LEDs in parallel. Each has a series resistor. I am using TINA to help me with the circuit design. There are two issues, the current has a slow ramp when I add LEDs in parallel and I get a peak drive current near my max. I will be driving it with an FPGA that can push 13mA. I need to drive it at 0.1ms intervals. See my TINA file or pdf. Is there a better transistor for this application? I could add a buffer like an OR gate if needed.

 

[AnalogKid]

What is the value of V19?

What are the amplitude, frequency, and positive pulse width of VG1?

the current has a slow ramp

What current; there are two indicated on the schematic. What are the details of the ramp?

Your questions is not clear about what you are trying to achieve. Are you trying to drive the LEDs with pulse width modulation (PWM) to vary the brightness?

ak

 

[Alec_t]

If LED current is 13mA and each LED is lit for only 0.1ms I don't think they will appear very bright.