Voltage regulator voltage overshoot look-back

Abstract

A deglitch circuit, or look-back, may be used to reduce or avoid reacting to a transient overvoltage situation by a voltage regulator. The voltage regulator may delay reacting to an overvoltage situation unless the overvoltage situation persists for more than a first programmable number of cycles.

1 . A voltage regulation circuit, comprising:
 a plurality of switching converters, each switching converter comprising a high side switch and a low side switch coupled in series between a higher voltage and a lower voltage, with an output inductor having a first end coupled to a node between the high side switch and the low side switch and a second end coupled to a load, with a bypass switch in parallel to the inductor;   an output capacitor coupled to the switching converters in parallel to the load;   an overvoltage comparator for determining if voltage provided to the load is over an overvoltage threshold and providing an overvoltage indicator based on results of the determination;   a circuit for providing an indication of a number of clock cycles that the overvoltage indicator indicates that the voltage provided to the load is over the overvoltage threshold; and   a controller configured to operate the high side switch, the low side switch, and the bypass switch of each phase based on the indication of the number of clock cycles that the overvoltage indicator indicates that the voltage provided to the load is over the overvoltage threshold, with the controller configured to open the high side switch and the low side switch and close the bypass switch for at least one of the switching converters and open the bypass switch for others of the switching converters when the indication of the number of clock cycles that the overvoltage indicator indicates that the voltage provided to the load is over the overvoltage threshold indicates a number of cycles greater than a first target number.   
     
     
         2 .- 4 . (canceled) 
     
     
         5 . The voltage regulator of  claim 1 , wherein the controller is further configured to open the high side switch and the low side switch and close the bypass switch for the others of the switching converters when the indication of the number of clock cycles that the overvoltage indicator indicates that the voltage provider to the load is over the overvoltage threshold indicates a number of cycles greater than a second target number. 
     
     
         6 . The voltage regulator of  claim 5 , wherein the controller is further configured to maintain at least some of switching converters with the high side switch and the low side switch open and the bypass switch closed for a plurality of cycles after the overvoltage indicator no longer indicates that the voltage provided to the load is over the overvoltage threshold. 
     
     
         7 .- 9 . (canceled) 
     
     
         10 . A method useful in operating a multi-phase DC-DC switching voltage regulator, the multi-phase DC-DC switching voltage regulator having a plurality of parallel phases coupled to an output capacitor and a load in parallel, each phase including a high side switch and a low side switch coupled in series, with an inductor having a first end coupled to a node between the high side switch and the low side switch and a second end coupled to an output capacitor in parallel to a load, and a bypass switch coupled between the first end of the inductor and the second end of the inductor, a voltage at a node between the inductor, output capacitor, and the load being an output voltage of the multi-phase DC-DC switching voltage regulator, the method comprising:
 determining that the output voltage exceeds an overvoltage threshold for a first programmable number of cycles, the programmable number of cycles being at least a plurality of cycles;   responsive to determining that the output voltage exceeds the overvoltage threshold for the first programmable number of cycles, closing the bypass switch for each of a first plurality of phases;   determining that the output voltage exceeds the overvoltage threshold for a second programmable number of cycles, the second programmable number of cycles being greater than the first programmable number of cycles;   responsive to determining that the output voltage exceeds the overvoltage threshold for a second programmable number of cycles, closing the bypass switch for each of a second plurality of phases.   
     
     
         11 . The method of  claim 10 , further comprising:
 determining that the output voltage exceeds the overvoltage threshold for at least one cycle;   responsive to determining that the output voltage exceeds the overvoltage threshold for at least one cycle, closing the bypass switch for at least one phase, the at least one phase not being a phase in the first plurality of phases.   
     
     
         12 . The method of  claim 11 , wherein the at least one phase consists of one phase. 
     
     
         13 . The method of  claim 10 , further comprising:
 determining that the output voltage no longer exceeds the overvoltage threshold; and   responsive to determining that the output voltage no longer exceeds the overvoltage threshold, opening the bypass switch for some, but not all, of the phases of the first plurality of phases and the second plurality of phases.   
     
     
         14 . The method of  claim 13 , further comprising:
 determing that the output voltage no longer exceeds the overvoltage threshold for a third number of the cycles; and   responsive to determing that the output voltage no longer exceeds the overvoltage threshold for a third number of the cycles, opening the bypass switch for others of the phases of the first plurality of phases and the second plurality of phases.