Switch-Mode Converter Operating in a Hybrid Discontinuous Conduction Mode (DCM)/Continuous Conduction Mode (CCM) That Uses Double or More Pulses in a Switching Period

Abstract

A switching converter controller and method for controlling a switch-mode converter in a hybrid discontinuous conduction mode (DCM)/continuous conduction mode (CCM) mode are disclosed. The hybrid mode involves using double (two) or more switching pulses in a switching period of a control signal for controlling the switch-mode converter. The switching period is defined by a switch on-time duration, a switch off-time duration, and an N number of switching pulses. N is an integer greater than one. An inductor current through the inductor of the switch-mode converter is zero before an initial switching pulse, is zero after a last switching pulse, and is non-zero for all other times within the switching period. The switch-mode-converter controller can be used as a power factor correction controller for a power factor corrector. The switch-mode converter controller can be implemented on a single integrated circuit.

1 . A switching converter controller for controlling a switch-mode converter which has a switch and an inductor coupled to the switch wherein the switch-mode converter receives an input voltage and provides an output voltage, comprising:
 a finite state machine configured to operate the switch-mode converter in a hybrid discontinuous conduction mode (DCM)/continuous conduction mode (CCM) mode; and   wherein the finite state machine defines a switching period for a control signal for controlling the switch based on an on-time duration of the switch and an off-time duration of the switch and wherein an average inductor current is calculated for the switching period from the on-time-duration of the switch and the off-time duration of the switch.   
     
     
         2 . The switching converter controller of  claim 1  wherein the finite state machine defines the switching period for the control signal for controlling the switch also based on an N number of switching pulses defined within the switching period wherein N is an integer greater than one and wherein the average inductor current through the inductor is zero before an initial switching pulse of the N number of switching pulses, is zero after a last switching pulse of the N number of switching pulses, and is non-zero for all other times within the switching period. 
     
     
         3 . The switching converter controller of  claim 2  wherein the N number of switching pulses is two switching pulses and the hybrid DCM/CCM mode is a hybrid DCM/CCM double-pulse mode. 
     
     
         4 . The switching converter controller of  claim 2  wherein the N number of switching pulses is three switching pulses and the hybrid DCM/CCM mode is a hybrid DCM/CCM triple-pulse mode. 
     
     
         5 . The switching converter controller of  claim 2  wherein for a subsequent switching pulse after the initial switching pulse and before the last switching pulse, the switch is turned on for a fraction of the on-time duration and the switch is turned off for the fraction of the off-time duration, wherein the fraction is greater than zero and less than one and is defined by a ratio of a width of the subsequent switching pulse to a width of the initial switching pulse. 
     
     
         6 . The switching converter controller of  claim 5  wherein the fraction is selected as an optimal value in a range between 0.25 and 0.50. 
     
     
         7 . The switching converter controller of  claim 1  wherein the switching converter controller is a power factor correction (PFC) controller for controlling the switch-mode converter that is a switch-mode boost converter. 
     
     
         8 . A method for controlling a switch-mode converter which has a switch and an inductor coupled to the switch wherein the switch-mode converter receives an input voltage and provides an output voltage, comprising:
 configuring to operate the switch-mode converter in a hybrid discontinuous conduction mode (DCM)/continuous conduction mode (CCM) mode;   defining a switching period for a control signal for controlling the switch based on an on-time duration of the switch and an off-time duration of the switch; and   calculating an average inductor current for the switching period from the on-time duration of the switch and the off-time duration of the switch.   
     
     
         9 . The method of  claim 8  further comprising:
 defining a switching period for the control signal for controlling the switch also based on an N number of switching pulses defined within the switching period wherein N is an integer greater than one and wherein the average inductor current through the inductor is zero before an initial switching pulse of the N number of switching pulses, is zero after a last switching pulse of the N number of switching pulses, and is non-zero for all other times within the switching'period. 
 
     
     
         10 . The method of  claim 9  wherein the N number of switching pulses is two switching pulses and further comprising:
 configuring to operate the switch-mode converter in a hybrid DCM/CCM double-pulse mode. 
 
     
     
         11 . The method of  claim 9  wherein the N number of switching pulses is three switching pulses and further comprising:
 configuring to operate the switch mode converter in a hybrid DCM/CCM triple-pulse mode. 
 
     
     
         12 . The method of  claim 9  further comprising:
 defining a fraction, that is greater than zero and less than one, based on a ratio of a width of a subsequent switching pulse after the initial switching pulse and before the last switching pulse to a width of the initial switching pulse; and for the subsequent switching pulse, turning on the switch for a fraction of the on-time duration and turning off the switch for the fraction of the off-time duration. 
 
     
     
         13 . The method of  claim 12  wherein defining the fraction further comprises:
 selecting an optimal value for the fraction in a range between 025 and 0.50. 
 
     
     
         14 . The method of  claim 8  further comprising:
 controlling the switch-mode converter that is a switch-mode boost converter which is used in a power factor corrector. 
 
     
     
         15 . An integrated circuit which incorporates a switch-mode converter controller for controlling a switch-mode converter which has a switch and an inductor coupled to the switch wherein the switch-mode converter receives an input voltage and provides an output voltage, and wherein the switch-mode converter controller includes a finite state machine, the integrated circuit configured to:
 operate the switch-mode converter in a hybrid discontinuous conduction mode (DCM)/continuous conduction mode (CCM) mode;   define a switching period for a control signal for controlling the switch based on an on-time duration of the twitch and an off-time duration of the switch; and   calculating an average inductor current for the switching period from the on-time duration of the switch and the off-time duration of the switch.   
     
     
         16 . The integrated circuit of  claim 15  further configured to:
 define the switching period for the control signal for controlling the switch also based on an N number of switching pulses defined within the switching period wherein N is an integer greater than one and wherein the average inductor current through the inductor is zero before an initial switching pulse of the N number of switching pulses, is zero after a last switching pulse of the N number of switching pulses, and is non-zero for all other times within the switching period. 
 
     
     
         17 . The integrated circuit of  claim 16  further configured to:
 set the N number of switching pulses to two switching pulses; and 
 operate the switch-mode converter in a hybrid DCM/CCM double-pulse mode. 
 
     
     
         18 . The integrated circuit of  claim 16  further configured to:
 set the N number of switching pulses to three switching pulses; and 
 operate the switch-mode converter in a hybrid DCM/CCM triple-pulse mode. 
 
     
     
         19 . The integrated circuit of  claim 16  further configured to:
 define a fraction, that is greater than zero and less than one, based on a ratio of a width of a subsequent switching pulse after the initial switching pulse and before the last switching pulse to a width of the initial switching pulse; and 
 for the subsequent switching pulse, turn on the switch for a fraction of the on-time duration and turn off the switch for the fraction of the off-time duration. 
 
     
     
         20 . The integrated circuit of  claim 19  further configured to:
 select the fraction as an optimal value in a range between 0.25 and 0.50. 
 
     
     
         21 . The integrated circuit of  claim 15  further configured to:
 control the switch-mode converter that is a switch-mode boost converter which is used in a power factor corrector. 
 
     
     
         22 . A power factor corrector (PFC), comprising:
 a switch-mode boost stage having a switch and an inductor coupled to the switch wherein the switch-mode boost stage receives a rectified line input voltage and provides a link output voltage;   a target current generator for receiving the link output voltage and for generating a target current proportionate to the rectified line input voltage; and   a finite state machine configured to operate the switch-mode boost stage in a hybrid discontinuous conduction mode (DCM)/continuous conduction mode (CCM) mode wherein the finite state machine defines a switching period for a control signal for controlling the switch based on an on-time duration of the switch and an off-time duration of the switch and wherein an average inductor current is calculated for the switching period from the on-time duration of the switch and the off-time duration of the switch.   
     
     
         23 . The PFC of  claim 22  wherein the finite state machine defines the switching period for the control signal for controlling the switch also based on an N number of switching pulses defined within the switching period wherein N is an integer greater than one and wherein the average inductor current through the inductor is zero before an initial switching pulse of the N number of switching pulses, is zero after a last switching pulse of the N number of switching pulses, and is non-zero for all other times within the switching period. 
     
     
         24 . The PFC of  claim 23  wherein the N number of switching pulses is two switching pulses and the hybrid DCM/CCM mode is a hybrid DCM/CCM double-pulse mode. 
     
     
         25 . The PFC of  claim 23  wherein the N number of switching pulses is three switching pulses and the hybrid DCM/CCM mode is a hybrid DCM/CCM triple-pulse mode. 
     
     
         26 . The PFC of  claim 23  wherein for a subsequent switching pulse after the initial switching pulse and before the last switching pulse, the switch is turned on for a fraction of the on-time duration and the switch is turned off for the fraction of the off-time duration, wherein the fraction is greater than zero and less than one and is defined by a ratio of a width of the subsequent switching pulse to a width of the initial switching pulse. 
     
     
         27 . The PFC of  claim 26  wherein the fraction is selected as an optimal value in a range between 0.25 and 0.50.