BQ25703A: With out BAT, Vsys not output power

user6216917

Part Number: BQ25703A

Hi ，

Without BAT( CELL_BATPRES:0 V), Vsys connect to backup battery

The system supply by batteryup battery, and insert Input power source(19V or 15V)。 The Vsys will drop and power on again. What reason leading the issue?

And I use BQ25703AEVM to debug, if set to no BAT, inset power source(without wirte I2C register ), Vsys no output power.

If set to 2cell, inset power source(without wirte I2C register ), Vsys output 6.12V.

Is it because the I2C register was written in the wrong time？And other reason?

over 4 years ago

0 Tiger Zhou over 4 years ago

TI__Mastermind 32745 points

The BQ25703A needs to detect the cell configuration before starting up into the correct system voltage. Please follow our BQ25703AEVM as a guideline.

0 user6216917 over 4 years ago in reply to Tiger Zhou

Prodigy 110 points

Hi，

The BQ25703A will start up into the correct system voltage when detect 1-4Cell.

If detecting no Cell installed, what's behave?

0 Tiger Zhou over 4 years ago in reply to user6216917

TI__Mastermind 32745 points

Hi, Could you share your schematic? Not sure if you follow our EVM schematic.

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BQ25703A: With out BAT, Vsys not output power