ZHCSGN5B March 2017 – July 2018 LP8863-Q1
PRODUCTION DATA.
An integrated 2X charge pump can be used to supply the gate drive for the external FET of the boost controller. The charge pump is enabled or disabled by automatically detecting the presence of the external C2X capacitor. If VDD is < 4.5 V then use the charge pump to generate a high-enough gate voltage to drive the external boost switching FET. To use the charge pump, a 2.2-µF cap is placed between C1N and C1P. If the charge pump is not required, C1N and C1P must be left unconnected and CPUMP pins tied to VDD. A 10-µF CPUMP capacitor is used to store energy for the gate driver. The CPUMP capacitor is required to be used in both charge pump enabled and disabled conditions and must be placed as close as possible to the CPUMP pins. Figure 14 and Figure 15 show required connections for both use cases.
The C2X_STAT status bit shows whether a C2X capacitor was detected. The C2X_INT bit shows status of any charge pump faults and generates a INT signal. The C2X_INT bit can be used to prevent the charge-pump fault from causing an interrupt on the INT pin signal.