Optimizing the Control of a Hysteretic Power Converter at Low Duty Cycles

Abstract

A method for controlling a current associated with a power converter may comprise controlling the current based on at least a peak current threshold level for the current and a valley current threshold level for the current, and further controlling the current based on a duration of time that the power converter spends in a switching state of the power converter.

1 . A method for controlling a current associated with a power converter, comprising:
 controlling the current based on at least a peak current threshold level for the current and a valley current threshold level for the current; and   further controlling the current based on a duration of time that the power converter spends in a switching state of the power converter.   
     
     
         2 . The method of  claim 1 , further comprising switching the power converter between a charging state in which the current increases and a transfer state in which the current decreases. 
     
     
         3 . The method of  claim 2 , further comprising switching the power converter between the transfer state and the charging state based on the duration of time. 
     
     
         4 . The method of  claim 3 , wherein the duration of time comprises a duration of time of the transfer state, and the method further comprises switching the power converter from the transfer state to the charging state if the duration of time exceeds a threshold duration. 
     
     
         5 . The method of  claim 1 , further comprising measuring the duration of time with a timer. 
     
     
         6 . The method of  claim 5 , further comprising resetting the timer at the start of the switching state. 
     
     
         7 . The method of  claim 6 , wherein the switching state is a transfer state of the power converter in which the current decreases. 
     
     
         8 .- 11 . (canceled) 
     
     
         12 . A control circuit for controlling a current associated with a power converter, the control circuit comprising:
 threshold-based control circuitry configured to control the current based on at least a peak current threshold level for the current and a valley current threshold level for the current; and   timer-based control circuitry configured to control the current based on a duration of time that the power converter spends in a switching state of the power converter.   
     
     
         13 . The control circuit of  claim 12 , wherein the control circuit is configured to switch the power converter between a charging state in which the current increases and a transfer state in which the current decreases. 
     
     
         14 . The control circuit of  claim 13 , wherein the timer-based control circuitry is configured to switch the power converter between the transfer state and the charging state based on the duration of time. 
     
     
         15 . The control circuit of  claim 14 , wherein the duration of time comprises a duration of time of the transfer state, and the timer-based control circuitry is configured to switch the power converter from the transfer state to the charging state if the duration of time exceeds a threshold duration. 
     
     
         16 . The control circuit of  claim 12 , wherein the timer-based control circuitry is further configured to measure the duration of time with a timer. 
     
     
         17 . The control circuit of  claim 16 , wherein the timer-based control circuitry is further configured to reset the timer at the start of the switching state. 
     
     
         18 . The control circuit of  claim 17 , wherein the switching state is a transfer state of the power converter in which the current decreases. 
     
     
         19 .- 22 . (canceled) 
     
     
         23 . A device comprising:
 a power converter; and   a control circuit for controlling a current associated with the power converter, the control circuit comprising:
 threshold-based control circuitry configured to control the current based on at least a peak current threshold level for the current and a valley current threshold level for the current; and 
 timer-based control circuitry configured to control the current based on a duration of time that the power converter spends in a switching state of the power converter.