Part Number: LM7480-Q1
Other Parts Discussed in Thread: LM74800-Q1
Hi,
I am designing a power supply with battery charge and discharge functions. I need to cancel reverse current protection of LM7480-Q1 thus allowing bi-directional current flow., and still maintaining on/off control and reverse battery voltage protection.
Can you confirm if using the part LM74801-Q1 instead of LM74800-Q1 + leaving the "C" pin floating + using common drain configuration works for my project.
Best Regards
Hi Olus,
Yes, you are right.
LM74801-Q1 in common drain configuration can allow bi-directional current flow when the "C" pin is left floating.
Hi Olus,
What do you mean by 'switch current direction modes' - do you want to enable and disable the bi-directional current flow by connecting and disconnecting the C pin to drain of the FET ? This can be achieved by connecting a logic FET (and control it using an external control signal) in between the C pin and the drain of the FET.
Unfortunately, we cannot reveal the internal structure of pin "C". The voltage across A-C is continuously monitored and the gate is controlled accordingly as described in the datasheet.
Yes, you can leave the pin floating without any issue. This is also specified in the datasheet as shown below.
Since the current always flows into the C pin, we can use a logic FET to disconnect it in the orientation shown below to disconnect it. Alternatively, you can use a BJT in place of logic FET to block bidirectional current (from and to C pin) when turned OFF.
