ZHCSBK4G March 2013 – March 2019
PRODUCTION DATA.
The bq25570 has five functional modes: cold start operation, main boost charger disabled (ship mode), main boost charger enabled, buck converter enabled mode and thermal shutdown. When VSTOR is greater than VSTOR_CHGEN (1.8 V typical), the bq25570's two enable pins allow for flexibility in controlling the system. The table below summarizes the functionality.
EN PIN LOGIC LEVEL | VOUT_EN PIN LOGIC LEVEL | FUNCTIONAL MODE |
---|---|---|
0 | 0 | Buck standby mode: boost charger and VBAT_OK are enabled. Buck converter is disabled. |
0 | 1 | Boost charger, buck converter and VBAT_OK enabled. |
1 | x | Ship mode (lowest leakage state): boost charger, PFET between VSTOR and VBAT is off, buck converter and VBAT_OK indication are disabled. |
The EN high voltage is relative to the VBAT pin voltage. VOUT_EN high voltage is relative to VSTOR. If it is not desired to control EN, it is recommended that this pin be tied to VSS, or system ground. When EN is low, VOUT_EN is used to enable and disable the buck converter. The high-level Functional Block Diagram highlights most of the major functional blocks inside the bq25570. The cold start circuitry is powered from VIN_DC. The main boost charger circuitry is powered from VSTOR while the boost power stage is powered from VIN_DC. Details of entering and exiting each mode are explained below.