Question
We are designing switched mode power supply units for the industry. We are
using the ADuM6132ARWZ because of its ideal fitting in our design in terms of
functionality. However we have to complain the extraordinary inherent power
consumption of this device of typically 200mA respectively 1,25 W at 5V supply,
or max. rated at 280mA or 1,4W according to its data sheet.
This unusual behaviour forces us to glue an unforeseen extra heat sink
(aluminium or ceramic) directly upon the device, which makes the manufacturing
process unhandy and unprofessional. Also the recommendation to apply extra
copper pads would not be very economic because this implies to vaste extra
space of the pcb.
Recently, we have realized that a similar device ADuM 3223/4223 having 2
separate coupled drivers only requires less than 10mA, which is considered as
normal, and is less than a factor of 25 times less than the internal
consumption of the ADuM 6132.
And idea what we could do rather than using the existing solution is highly
appreciated.
Answer
The ADuM6132 was made to a specific customer’s requirements. It does consume a
lot of power. You can also consider the ADuM5230 as an alternative. The power
can be controlled by setting the PWM duty factor externally so it does not get
as hot. The ADuM5230 is also getting popular in automotive applications.
The ADuM3223/4223 do not contain isoPower so they have much lower power
consumption, but power must be supplied from somewhere. We have several
alternative methods for doing the power job, including the ADuM3070 which can
make high output voltages and is much more efficient.