hi expert
as we known, LM74930-Q1 has CS+,CS- Imon pin to measure current.
Normally, current is from left to right, like red arrow shown. in this situation, CS+ voltage is larger than CS- voltage.
if current flow is from right to left.(MODE=Low).
Q1:does current measure function still work in this situation?
Q2: what is the limitation voltage of (CS-)-(CS+) ?
Q2: what is the limitation voltage of (CS-)-(CS+) ? 0.3V?
Hi Jay
LM74930-Q1 has a MODE pin by which reverse current blocking can be disabled. By which we can conclude that reverse current measuring is normal.
Thanks and Regards
Shiven Dhir
Hi Shiven
i use our LM74930 EVM to do test. the input voltage is shown below.
i adjust J6 Jumper(MODE connected to GND)
and then i make input voltage connect to "VOUT(J2)" and "PGND(J4)",make 4ohm to "VIN(J1)" and "PGND(J3)" and find there are no current.
it seems like reverse current path doesn't work. could you share your comments?
Hi Jay,
The VS pin has to be powered for the LM74930-Q1 device to work.
When you apply power at Vout and leave the input unpowered, the VS pin which is connected at the input will not be powered and hence the LM74930-Q1 will not work.
Reverse current will be allowed to flow when the input is powered but the input voltage is lower than output voltage and MODE is pulled low.
Also, the IMON pin is not deigned to work for reverse current. The IMON pin will work only for positive current or current flow from left to right as shown below.
hi Praveen
i use 7.03V connected to Vin and PGND, 4ohm resister is connected to Vin and PGND. Vout is not connected any power.
and then MODE PIN is connected to LOW. i use 11V connected to VOUT. i think it is reverse current. it works.
Q1: whether is the above test results reasonable?
Q1: if customer want to use reverse OCP and measure reverse current value, do you have any comments?
