Other Parts Discussed in Thread: BQ25985
We are using the BQ25895 in our product but only get 0.6V on Vsys with or without battery inserted. Board is powered by a non standard 5V 3A supply. We are using BQ Studio to read/write registers in the device since our host MCU can not start without Vsys, but the battery charger still limits Vsys.
Schematic excerpt below
Screen cap of BQ Studio
* Created: Wed Jun 19 14:40:20 CDT 2019 * * Format: Register Name tab Character,\t Hexadecimal register value. * BQZ Container: Charger_1_00-bq25890_895.bqz * Input Current Limit, HIZ and ILIM pin 7A OTG Temperature thresholds, and Input Voltage DPM Offset 05 ADC controls, OTG Frequency, ICO, DCP, and Input Detection 3D Battery Load, WDT Reset periods, OTG and Charge Enable, and MINSYS setting 3A Fast Charge Current Limit settings and MTK Pump enable 20 Pre-charge and Termination Current Limit settings 13 Charge Voltage Regulation Limit, Battery Low Voltage and Recharge threshold 5E Termination Current Enable, STAT pin, WDT, Safety Timer, and JEITA Charge Current 8D IR Compensation and Thermal Regulation thresholds 03 ICO, Extended Safety Timer, BATFET control, MTK Pump Voltage, and JEITA Charge Voltage 44 OTG Regulation Voltage and Current Limit settings 90 Charger VBUS, Charging Mode, PG, USB Input, and System Voltage Regulation status 6F WDT, OTG/VBUS OVP, Thermal Shutdown, Safety Timer, and TS pin faults 00 Input Voltage DPM settings 14 Thermal Regulation Charge Status, and ADC Battery Voltage conversion 00 ADC System Voltage conversion 00 ADC TS pin voltage as percentage of REGN conversion 00 VBUS status, and ADC VBUS Voltage conversion 99 ADC Charge Current conversion 00 DPM status, and Input Current Limit setting 42 Registers reset, Input Current Optimizer status, Device ID, and Temperature Profile 39
Are we missing some other register configurations to bring Vsys up?
