A Circuit to Prevent Shutdown Against Branch and Power Supply Short
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2003-Jun-20
Problem A large system uses multiple processors and RAID systems to process information as shown in Figure 1. In such systems, each branch circuit can draw up to 240 VA power. If the branch tries to draw more than this VA limit, a signal is generated to shut down the whole power system. Prior Art Figure 1 shows three power supplies PS1, PS2 and PS3 in parallel to provide a bus voltage of V. Individual outputs from each power supply are ORed on a power back-plane which serves as a distribution point for all the power delivered to the system. The back plane has a current sense circuit for each branch to limit the power to 240 VA. In Figure 1, Rcs1 and Rcs2 are current sense resistors. As and when the current in a current sense resistor exceeds 240VA threshold requirement, it generates an over-current signal to shut down the whole system as shown in Figure 2.