BQ24610 Charge current does not match what is specified by ISET1

Ray Weymer

Hello-

I have a resistor divider set up so that I am inputting 0.3V into the Iset1 pin (I verified it). With a sense resistor of 0.010 ohms this should yield a charge current of 1.5A. What I measure and what is reported by the gas gauge is approximately 980mA of charge current. Any idea why this is??

I thought the current might be being throttled by ACset but I have no load attached and if I attach a load the current does not change.

The charge cycle should be in constant voltage range since it hasn't reached the charge voltage of 12.6V so the current should be at full strength and not be tapering down.

Any insight on this would be appreciated

-Ray

over 13 years ago

0 Charles Mauney over 13 years ago

TI__Mastermind 31120 points

The ACSET has to be programmed high enough so this is not restricting the input current and the input source has to able to supply enough current and voltage.

0 Ray Weymer over 13 years ago in reply to Charles Mauney

Prodigy 120 points

The ACSET is programmed high enough. If it wasn't and I turned on the load the current would drop further but it doesn't drop further. ACSET is set at .96V which corresponds to 4.8A. this is more than enough current especially since I have no load attached.

0 Charles Mauney over 13 years ago in reply to Ray Weymer

TI__Mastermind 31120 points

Charge current tapers once CV mode is hit and is a function of the battery resistance.

Is the current correct with the voltage is well below the regulation threshold?

0 Ray Weymer over 13 years ago in reply to Charles Mauney

Prodigy 120 points

The current is still too low even with the the voltage well below the regulation threshold. I am seeing about 950mA even though I have a voltage divider of 100K and 10K and using VREG which is 3.3V. I need to take the 10K up to 16.6K to get the 1.5A I am looking for.

0 Charles Mauney over 13 years ago in reply to Ray Weymer

TI__Mastermind 31120 points

What is the voltage at the SRP and SRN pins.

The value of the sense resistor is the resistance between the sense connections, so any added trace resistance between the sense connection will reduce the charge current.

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BQ24610 Charge current does not match what is specified by ISET1