Hi all
Here comes a question on NVDC for the BQ25606NVDC:
Does this charger also limit NVDC VSYS current when it senses droop in VBUS, so that the power adapter is also protected from non-charging loads as well?
Best regards
Ueli
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Hi all
Here comes a question on NVDC for the BQ25606NVDC:
Does this charger also limit NVDC VSYS current when it senses droop in VBUS, so that the power adapter is also protected from non-charging loads as well?
Best regards
Ueli
Hey Ueli,
That is partially correct. To the charger, the charging current and system load are all part of the output power. When the input power is at the set threshold (via IINDPM or VINDPM), it will limit the output power. Normally, this will reduce the charge current if possible. However, in a continued overload case or when the battery is not present, it will allow the system voltage to droop.
Regards,
Joel H
... let me also post some additional comments ..
To meet maximum current limit in USB spec and avoid over loading the adapter, the device features Dynamic Power management (DPM), which continuously monitors the input current and input voltage. When input source is over-loaded, either the current exceeds the input current limit (IIDPM) or the voltage falls below the input voltage limit (VINDPM). The device then reduces the charge current until the input current falls below the input current limit and the input voltage rises above the input voltage limit. When the charge current is reduced to zero, but the input source is still overloaded, the system voltage starts to drop. Once the system voltage falls below the battery voltage, the device automatically enters the supplement mode where the BATFET turns on and battery starts discharging so that the system is supported from both the input source and battery.
Input Voltage Limit Threshold Setting (VINDPM Threshold)
The device supports wide range of input voltage limit (3.9 V – 5.4V) for USBThe device's VINDPM is set at 4.5V. The device supports dynamic VINDPM trackingsettings which tracks the battery voltage. This function can be enabled via the VDPM_BAT_TRACK[1:0] register bits. When enabled, the actual input voltage limit will be the higher of the VINDPM register and VBAT + VDPM_BAT_TRACK offset.
Hey Ueli,
I just want to add one more comment above supplement mode.
In the overload case I mentioned previously, if the battery is present and not depleted, a continually increasing system load with eventually reduce the charge current so much that the battery will instead supplement the system current.
Regards,
Joel H