Pulse width modulation controller architectures
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, the 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 PWM cycle duration that occurs during the first voltage cycle, wherein the maximum off-duration is determined based on the maximum PWM cycle duration and the on-duration parameter value in use during the maximum PWM cycle 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 the 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 PWM cycle duration that occurs during the first voltage cycle, wherein the maximum off-duration is determined based on the maximum PWM cycle duration and the on-duration parameter value in use during the maximum PWM cycle 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 the 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. A method comprising:
receiving 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;
receiving a second signal indicating a zero detection of a current through the inductor;
providing a pulse width modulation (PWM) signal that controls the 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 the on-duration, and wherein a start of each on-duration is triggered by a current trigger event indicated by the second signal;
determining 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
adjusting the on-duration parameter value for a second, subsequent voltage cycle based on the maximum off-duration to regulate the output voltage.
19. The method of claim 18 , further comprising:
operating a timer counter;
capturing a value of the timer counter based on the current trigger event; and
resetting the timer counter based on the current trigger event.
20. The method of claim 19 , further comprising:
performing a comparison between a value of a register and the value of the timer counter; and
loading the register with the value of the timer counter.