2. Continuous dimming control is implemented by applying a DC control voltage to the FB pin of the MIC2287 through a series resistor as shown in Figure 2. The LED intensity (current) can be dy- namically varied applying a DC voltage to the FB pin. The DC voltage can come from a DAC signal, or a filtered PWM signal. The advantage of this approach is a high frequency PWM signal(>lOkHz) that can be used to control LED intensity.
PC44EPC17-E33508F on stock| | | | | | _ |
| | 1500c ------ | _ | | | |
| | 1250C | | | | jj |
| j | | | | | |
| | 10100C | | | _ | |
| | _ - | | | ____ | __ |
| | 750C | | _ | | |
| | | | | ___ ___ | j |
| | 50 0C Jr | | _ __J | ___ __ | j |
| | 250C | j - | | | |
| jf | | | | | |
| | | | | VR lV |
| | | | | |
| Closed loop gain | Rr(kQ) | CF (pF) | R1(n) | C1 (nF) | C2 (pF) | Risellme (ps) | Slew Rate (V/Lrs) |
| 250 100 50 20 5 2 1 | 10 10 10 10 10 10 10 0 | 10 10 10 10 10 10 | 68 68 68 68 68 68 15 | 4.7 4.7 4.7 4.7 4.7 4.7 22 | 3.3 7.5 15 33 68 330 | 0.35 0.65 0.55 0.4 0.35 0.3 0.22 0.33 | 45 12 10 8 5 3 1.7 1. 5 |
| | | | | | | |
