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AS3668

Data Sheet - Detailed Description

If the voltage on the I²C signal lines is bigger than VPOR_PERI for a time frame longer than tPOR_DEB, the device changes it’s operation mode

from power off to standby mode. In this use state only the power on reset and the I²C block of the device is active with an average current

consumption of 10μA(typ.). The device changes its operating mode from standby to active mode automatically if one of the following blocks

inside AS3668 are activated:



Charge Pump



Current Source



Pattern Mode activated



External PWM mode via GPIO/AUDIO_IN

In addition to the I²C monitoring for startup of the device it is possible to power up AS3668 with GPIO/AUDIO_IN pin while the I²C signal lines are

low. this is a special use case which starts a predefined pattern on current source CURR1. For a detailed description please refer to chapter

8.7.1.

Besides the monitoring of the I²C signal lines there is also an additional feature which monitors the battery supply voltage VBAT. Basically there

are two voltage levels where this voltage monitoring becomes active. The first voltage VPOR_VBAT can be seen as a shut down and minimum

supply voltage of the device voltage which is fixed at 2V (typ.). The same voltage level is used for the power on reset circuit. If the battery voltage

drops below VPOR_VBAT the device automatically changes from active mode or standby mode to off mode. Besides the VPOR_VBAT level there

is a second VBAT monitoring voltage which can be activated in a register. This voltage VMON_VBAT is typically set to 3.4V (default register

setting) but can be reconfigured using the I²C interface down to 2.4V according to the requirements of an application. It is also possible to disable

the VBAT monitoring. The VPOR_VBAT monitoring can not be disabled.

Table 23. Truth Table for AS3668 operating modes

AS3668 Blocks

Off Mode

Standby Mode

Active Mode

Power On/Off Reset

enabled

I²C

disabled

enabled

Charge Pump

disabled

enabled/disabled depending on

Current Sources

disabled

enabled/disabled depending on

Pattern Mode

disabled

enabled/disabled depending on

External PWM

disabled

enabled/disabled depending on

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