Theres 2 figures in series connection (2x LED-s -- 1 per figure) -- since the least energy gets lost that way -- here what got implemented :
. . . the crystal balls´re not from the original set . . .
i actually researched the cc design-line further for Op Amps as i attempted to control 555 charging cycle as shown below . . .
. . . and the best results (for misc. cc - sink) gave the next weird setup (no good for PWM or pulsed setup)
unusual use of 555 timer in phase shift osc. setup . . . the modulation input - has no desired effect here - coz lowering the upper trigger level dis-balances the charging currents that'd need to be cc sourced - but for 500kHz i didn't wanted to extend the test for here . . .
update 2016-12-21 14:38 UTC+2h (-2h UTC) ::
opti´ng the timer out of the circuit ???