I have a 24x16 LED matrix - the 16 rows are connected by transistors driven by a pair of 74ac138s and the 24 rows by 3 TLC5916s. Refresh rate is 10K Hz (0.1us).
I want the lights to be as bright as possible so I'm overdriving them with 100 mA pulses...at least that's what things should be if I did the calculations right.
When I measure a row's draw I know I won't see 2400 mA (24 LEDs @ 100 mA ea) since it's only being powered 1/16th of the time, but my meter says ~38mA instead of the 150 I'd expect (2400 / 16).
On each column the meter says ~63mA. I know it won't say 100mA because the display is off for 3-4ms each update, but 63mA seems low...
Maybe my meter is so off because it doesn't average pulses very well?
My meter only goes up to 500mA so I can't do the easy thing and just measure total circuit draw.
My question is should I just get a new meter with a higher current capacity, or is there something like an oscilloscope etc. to more accurately measure pulsed current? If so are there any models you recommend?
Thanks in advance.