LT3652 transition from shutdown to charge

Hello,

Do you mean when the part is not in SHDN and not charging? Any battery charger will pull some current from the battery when not charging if VIN is not present, just to stay alive. Several mA seems high, though. I can't speak for the Sunny Buddy design as it is done by a third-party manufacturer, but the LT3652 has a quirk where it allows some leakage back to VIN through the BAT pin (part of the reason for the blocking diode on the input). If you have significant leakage paths to GND from VIN (setting resistors, etc), that will increase the drain on the battery. This should still all be very little leakage current, though.

I can't speak for the LTM8062 but perhaps someone else can.

Also, consider LTC4162 for cheap, monolithic, battery charger operation with a very low leakage current and a lot of other great features (you can use it standalone as well, despite the digital interface).

Regards,

Zack

Hello,

Do you mean when the part is not in SHDN and not charging? Any battery charger will pull some current from the battery when not charging if VIN is not present, just to stay alive. Several mA seems high, though. I can't speak for the Sunny Buddy design as it is done by a third-party manufacturer, but the LT3652 has a quirk where it allows some leakage back to VIN through the BAT pin (part of the reason for the blocking diode on the input). If you have significant leakage paths to GND from VIN (setting resistors, etc), that will increase the drain on the battery. This should still all be very little leakage current, though.

I can't speak for the LTM8062 but perhaps someone else can.

Also, consider LTC4162 for cheap, monolithic, battery charger operation with a very low leakage current and a lot of other great features (you can use it standalone as well, despite the digital interface).

Regards,

Zack