Pulse width modulation controller architectures

Abstract

Systems, apparatuses, and techniques for pulse width modulation (PWM) are described. A described system includes a circuit that contains an inductor and a transistor that controls current through the inductor based on a PWM signal to produce an output; and a controller to provide the PWM signal, which includes PWM cycles that include on-durations and off-durations. The controller can receive a first signal indicating an input voltage that is applied to the inductor, receive a second signal indicating a current through the inductor, use an on-duration parameter value to control the on-duration, determine a maximum off-duration of the off-durations corresponding to the PWM cycles occurring within a first voltage cycle, the first voltage cycle being defined between two consecutive zero-crossing events as indicated by the first signal, and adjust the on-duration parameter value for a second, subsequent voltage cycle based on the maximum off-duration to regulate the output voltage.

1 . An apparatus comprising:
 a first input interface to receive a first signal indicating a zero detection of an input voltage that is applied to an inductor of a circuit, the circuit being configured to produce an output signal with an output voltage;   a second input interface to receive a second signal indicating a zero detection of a current through the inductor;   circuitry to provide a pulse width modulation (PWM) signal that controls, via a switch, a current through the inductor based on an on-duration parameter value, the PWM signal comprising PWM cycles that each comprise an on-duration and an off-duration, wherein the on-duration parameter value controls an on-state duration of the switch, and wherein a start of each on-duration is triggered by a current trigger event indicated by the second signal;   circuitry to determine a maximum off-duration of the off-durations corresponding to the PWM cycles occurring within a first voltage cycle, the first voltage cycle being defined between two consecutive zero-crossing events as indicated by the first signal; and   circuitry to adjust the on-duration parameter value for a second, subsequent voltage cycle based on the maximum off-duration to regulate the output voltage.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 timer circuitry that includes a timer counter;   circuitry to capture a value of the timer counter based on the current trigger event; and   circuitry to reset the timer counter based on the current trigger event.   
     
     
         3 . The apparatus of  claim 2 , further comprising:
 a register;   circuitry to perform a comparison between a value of the register and the value of the timer counter; and   circuitry to load the register with the value of the timer.   
     
     
         4 . The apparatus of  claim 1 , wherein the circuitry to adjust the on-duration parameter value is configured to adjust the on-duration parameter value further based on a maximum time that the inductor takes to demagnetize into a half period of input power during the first voltage cycle. 
     
     
         5 . The apparatus of  claim 1 , wherein the circuitry to determine the maximum off-duration comprises circuitry to capture a maximum duration of a PWM cycle that occurs during the first voltage cycle, wherein the maximum off-duration is determined based on the maximum duration and the on-duration parameter value in use during the maximum duration. 
     
     
         6 . The apparatus of  claim 1 , wherein the input voltage is supplied by an alternating current source, and wherein the circuitry to adjust the on-duration parameter value is programmed with a maximal voltage value associated with the alternating current source. 
     
     
         7 . A system comprising:
 a circuit comprising an inductor and a transistor that controls current through the inductor based on a pulse width modulation (PWM) signal, the circuit being configured to produce an output signal with an output voltage; and   a controller configured to provide the PWM signal, the PWM signal comprising PWM cycles that each comprise an on-duration and an off-duration, wherein the controller is configured to:   receive a first signal indicating an input voltage that is applied to the inductor,   receive a second signal indicating a current through the inductor, use an on-duration parameter value to control each on-duration,   cause a start of each on-duration based on a current trigger event indicated by the second signal,   determine a maximum off-duration of the off-durations corresponding to the PWM cycles occurring within a first voltage cycle, the first voltage cycle being defined between two consecutive zero-crossing events as indicated by the first signal, and   adjust the on-duration parameter value for a second, subsequent voltage cycle based on the maximum off-duration to regulate the output voltage.   
     
     
         8 . The system of  claim 7 , wherein the controller comprises:
 timer circuitry that includes a timer counter;   circuitry to capture a value of the timer counter based on the current trigger event; and   circuitry to reset the timer counter based on the current trigger event.   
     
     
         9 . The system of  claim 8 , wherein the controller comprises:
 a register;   circuitry to perform a comparison between a value of the register and the value of the timer counter; and   circuitry to load the register with the value of the timer counter.   
     
     
         10 . The system of  claim 7 , wherein the controller is configured to adjust the on-duration parameter value further based on a maximum time that the inductor takes to demagnetize into a half period of input power during the first voltage cycle. 
     
     
         11 . The system of  claim 7 , wherein the controller is configured to capture a maximum duration of a PWM cycle that occurs during the first voltage cycle, wherein the maximum off-duration is determined based on the maximum duration and the on-duration parameter value in use during the maximum duration. 
     
     
         12 . The system of  claim 7 , wherein the input voltage is supplied by an alternating current source, and wherein the controller is programmed with a maximal voltage value associated with the alternating current source. 
     
     
         13 . A system comprising:
 a circuit comprising an inductor and a transistor that controls current through the inductor based on a pulse width modulation (PWM) signal, the circuit being configured to produce an output signal with an output voltage;   a processor configured to provide an on-duration parameter value; and   a controller, communicatively coupled with the processor, configured to provide the PWM signal, the PWM signal comprising PWM cycles that each comprise an on-duration and an off-duration, wherein the controller is configured to receive a first signal indicating an input voltage that is applied to the inductor, receive a second signal indicating a current through the inductor, use the on-duration parameter value to control each on-duration, cause a start of each on-duration based on a current trigger event indicated by the second signal, determine a maximum off-duration of the off-durations corresponding to the PWM cycles occurring within a first voltage cycle, the first voltage cycle being defined between two consecutive zero-crossing events as indicated by the first signal, and   wherein the processor is configured to adjust the on-duration parameter value for a second, subsequent voltage cycle based on the maximum off-duration to regulate the output voltage.   
     
     
         14 . The system of  claim 13 , wherein the controller comprises:
 timer circuitry that includes a timer counter;   circuitry to capture a value of the timer counter based on the current trigger event; and   circuitry to reset the timer counter based on the current trigger event.   
     
     
         15 . The system of  claim 14 , wherein the controller comprises:
 a register;   circuitry to perform a comparison between a value of the register and the value of the timer counter; and   circuitry to load the register with the value of the timer counter.   
     
     
         16 . The system of  claim 13 , wherein the processor is configured to adjust the on-duration parameter value further based on a maximum time that the inductor takes to demagnetize into a half period of input power during the first voltage cycle. 
     
     
         17 . The system of  claim 13 , wherein the input voltage is supplied by an alternating current source, and wherein the processor is programmed with a maximal voltage value associated with the alternating current source. 
     
     
         18 - 20 . (canceled)