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I have designed an LTC4001 battery charger circuit based on the evaluation kit design with the following change:

- no thermistor is included and the NTC  pin is connected to ground.

The device is not building up the charge current.

It appears to attempt to start and then resets itself  continuously. The battery is in good condition and charges as expected using the evaluation board.

No FAULT signal is evident on the FAULT pin.

The input voltage is as expected but the output voltage is always the same as the battery voltage e.g. if the battery voltage out of circuit is 3.5V then the voltage on the BAT pin is 3.5V.

I expected it would be 4.3V.

I've seen a similar query to this here but the answer/ solution is not visible.

The board has been machine built. If the PAD on the underside is not correctly soldered would this cause the above problem.

  • Hello,

    Are you able to look with an oscilloscope to see if the VIN pin is drooping, the part starts to SW on the SW node, SS pin starts to rise, Prog pin gets a voltage, /CHRG, or FAULT pin move at all?

    Was the GND remote sensing used?

    How close was the PCB layout follow the eval board layout?

    A poor GND under the IC can definitely cause some unexpected problems.