TN0026

Power limit circuit

7/9

Figure 4.

LED balancing circuit - two transistor power limit, latch

The following two circuits are variations of the power limit circuit in Figure 4. They disable

the LED balancing circuit but will not latch it off.

Figure 5 shows a one transistor power limit LED balancing circuit (R11, R12 etc.). It has

fewer parts but a narrower fault tolerance detection range. Q11 is turned on through either

R11 or R13.

Figure 6 shows a two diode power limit LED balancing circuit (R11, R12 etc.). Q11 is turned

on through diodes D9 or D10

Figure 5.

LED balancing circuit - one transistor power limit