solution
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1, if the trigger protection IC overdischarge protection, there has been no external charging access. Cell consumables and lithium battery protection ics continue to drain the battery over time. Until the cell voltage is lower than 1.5-2.1V, the battery protection IC has stopped working, and only the cell self-consumption continues.
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2, at this time plug in the external charging, if the IC supports 0V charging, you can remove the lithium protection IC overdischarge protection. Because the voltage is too low, the headset (charging IC) will enter a pre-charge state and trickle charge. Trickle pre-charge time is generally from a few minutes to more than 20 minutes.
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During this period of time, if the battery charging can restore the voltage, the headset can be charged to normal working state.
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Reasons why Bluetooth headphones can't be turned on for a long time:
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1, long idle state, if the lithium battery pack has been due to self-consumption, and the system static power consumption in the discharge. When the lithium battery pack (polymer cell) battery is discharged to a voltage below 2.8-3.3V, the low voltage protection of the Bluetooth chip is triggered. At this time, the Bluetooth headset cannot be turned on, or it automatically turns off after being turned on. Prompts the user to charge, at this time if the user charges in time, the headset can be charged normally.
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2, if it is not charged in time, as time goes by. The battery will continue to consume power until the battery voltage falls below 2.7-2.4V. The battery protection IC triggers the overdischarge protection.
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The battery protection IC will turn off the mos tube, at which point the battery stops output power. Only battery protection ics and cell consumables continue to consume power. Bluetooth headset press to turn on, there will be no response.
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Charging the Bluetooth headset at this time will remove the overdischarge protection of the protection IC, and the headset (charging IC) will provide a trickle charge to the battery to a voltage higher than 2.8-3.0V. Then the headset starts to return to normal charging current.