SNVSBY7 March 2021 TPS92390
An integrated regulated 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 whether VDD and CPUMP pin are connected together. If VDD is < 4.5 V then use the charge pump to generate a 5-V gate voltage to drive the external boost switching FET. To use the charge pump, a 2.2-µF capacitor is placed between C1N and C1P. If the charge pump is not required, C1N and C1P could be left unconnected and CPUMP pins tied to VDD. A 4.7-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 7-1and Figure 7-2 show required connections for both use cases.
If the charge pump is enabled, the CPCAP_STATUS bit shows whether a fly capacitor was detected and the CP_STATUS bit shows status of any charge pump faults and generates an INT signal. The CP_INT_EN bit can be used to prevent the charge-pump fault from causing an interrupt on the INT pin.