ZHCSGN5B March 2017 – July 2018 LP8863-Q1
PRODUCTION DATA.
The LP8863-Q1 current-mode-controlled boost DC/DC controller generates the bias voltage for the LEDs. The boost is a current-mode-controlled topology with an 8-A cycle by cycle current limit. The boost converter senses the switch current and across the external sense resistor connected between ISNS and ISNSGND. A 25-mΩ sense resistor results in an 8-A cycle by cycle current limit.. Maximum boost voltage is configured with external FB-pin resistor divider connected between VOUT and FB. The FB-divider equation is described in Boost Adaptive Voltage Control.
Figure 9. Boost Controller Block Diagram The boost switching frequency is adjustable from 300 kHz to 2.2 MHz via an external resistor at BST_FSET (see Table 2).
| R_BST_FSET (kΩ) | BOOST FREQUENCY (kHz) |
|---|---|
| 3.92 | 303 |
| 4.75 | 400 |
| 5.76 | 606 |
| 7.87 | 800 |
| 11 | 1000 |
| 17.8 | 1250 |
| 42.2 | 1667 |
| 140 | 2200 |