I am using the TPS61090 in a portable application where the regulator is initially in shutdown mode (EN = 0). When the regulator is turned on (EN = 1), the inrush current to charge the regulator's output capacitor is causing the battery voltage to dip significantly, resulting in problems elsewhere in the circuit.
The TPS61090 is set to output 3V and the expected current draw on average is 20mA, with a maximum current of 400mA. During startup, the current draw is approximately 10mA. In order to reduce the output voltage ripple, the output capacitor was chosen to be 330uF with an ESR of 35mOhm (as per the datasheet).
The battery is a primary lithium battery with a nominal voltage of 3V with a bypass capacitor of 100uF. When the regulator turns on, the battery voltage dips to approximately 1.5V. This dip occurs well before the regulator starts switching during the soft-start phase. I believe that the inrush current is caused by the need to charge the 330uF capacitor.
Do you have any suggestions for reducing the inrush current? Or possibly another method for reducing the voltage drop in the battery? I will be trying out a 100uF capacitor in place of the 330uF capacitor, but I really do not want to increase the output ripple in my application.
Thank you for your help!