TN0026 Datasheet, PDF (7/9 Pages) STMicroelectronics – LED balancing circuits

TN0026
Power limit circuit
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
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