System and method for preventing undesirable substantially concurrent switching in multiple power circuits

Abstract

A power system includes a first charge pump configured to supply power, and control circuitry coupled to the first charge pump. The control circuitry is operable to receive a signal indicating whether a second change pump is turning on. If the first charge pump is about to be turned on and the signal indicates that the second charge pump is turning on, the control circuitry is operable to prevent an output, of first charge pump from substantially aligning with an output of the second charge pump.

What is claimed is: 
     
         1 . A power system comprising:
 a first charge pump configured to supply power;   control circuitry coupled to the first charge pump, the control circuitry operable to:
 receive a signal indicating whether a second charge pump is turning on; and 
 if the first charge pump is about to be turned on and the signal indicates that the second charge pump is turning on, prevent an output of first charge pump from substantially aligning with an output of the second charge pump. 
   
     
     
         2 . The power system as recited in  claim 1 , wherein the control circuitry is operable to prevent the output of first charge pump from substantially aligning with the output of the second charge pump by delaying the turning on of the first charge pump by a predetermined amount of time 
     
     
         3 . The power system as recited in  claim 1 , wherein the control circuitry is operable to prevent the output of first charge pump from substantially aligning with the output of the second charge pump by causing the output of the first charge pump to be out of phase with the output of the second charge pump. 
     
     
         4 . The power system as recited in  claim 1 , wherein the control circuitry is operable to cause the output of the first charge pump to be out of phase with the output of the second charge pump by phase shifting the output of the first charge pump by a predetermined amount of phase with respect to the output of the second charge pump. 
     
     
         5 . The power system as recited in  claim 1 , further comprising sense logic coupled between the second charge pump and the control circuitry, wherein detects a present state of the second charge pump and provides to the control circuitry the signal indicating that the second charge pump is turning on. 
     
     
         6 . The power system as recited in claim, wherein the sense logic, the control circuitry and the first charge pump reside on a common integrated circuit. 
     
     
         7 . The power system as recited in  claim 1 , wherein the first charge pump and the second charge pump reside on different integrated circuits.