Is it possible to parallel two LTC1550 for increased output current?

Hi ARL,

We never tried to connect the LTC1550s in parallel. Typically I would say no, there is no way to assure current sharing or to sync the frequency. Also each have their own control loop and will both try to regulate to 4V separately. However each have a high open loop impedance and this might be OK. The LTC1550 that regulates at the highest voltage will be supplying the current. If VOUT does start to droop because of IOUT*RDSON, the second LTC1550 will start supplying the current and keep the output in regulation. The only problem that might occur is the ripple voltage might periodically line up and provide a little higher ripple at some point because the frequencies can not sync up.

I think this should work fine but you should try this on the bench and make sure the output ripple and performance is acceptable.

Hi ARL,

We never tried to connect the LTC1550s in parallel. Typically I would say no, there is no way to assure current sharing or to sync the frequency. Also each have their own control loop and will both try to regulate to 4V separately. However each have a high open loop impedance and this might be OK. The LTC1550 that regulates at the highest voltage will be supplying the current. If VOUT does start to droop because of IOUT*RDSON, the second LTC1550 will start supplying the current and keep the output in regulation. The only problem that might occur is the ripple voltage might periodically line up and provide a little higher ripple at some point because the frequencies can not sync up.

I think this should work fine but you should try this on the bench and make sure the output ripple and performance is acceptable.