ZHCSLM4B August 2020 – May 2024 LP8864S-Q1
PRODUCTION DATA
The LP8864S-Q1 device supports VIN undervoltage and overvoltage protection. The undervoltage threshold is programmable through external resistor divider on UVLO pin. If during operation of the LP8864S-Q1 device, the UVLO pin voltage falls below the UVLO falling level (0.787V typical), the boost, LED outputs, and power-line FET will be turned off, and the device will enter STANDBY mode. The VINUVLO_STATUS bit is also set in the SUPPLY_FAULT_STATUS register, and the INT pin is triggered. When the UVLO voltage rises above the rising threshold level the LP8864S-Q1 exits STANDBY and begins the start-up sequence.
The following equation is used to calculate the UVLO threshold for VIN rising edge:
where
The hysteresis of UVLO threshold can be designed and calculated with the following equation.
where
So the following equation can be used for UVLO threshold for VIN falling edge:
The bottom resistors, R5 of voltage divider is able to be disconnected to the GND through an additional external N-type of FET as Figure 6-17. This design is to minimize the current leakage from VIN in shutdown mode to extend the battery life.