Systems and methods for constant current control with primary-side sensing and regulation in various operation modes

• US 9,812,970 B2
• Filed: 02/25/2016
• Issued: 11/07/2017
• Est. Priority Date: 05/05/2011
• Status: Active Grant

• Current Assignee: Guangzhou On-Bright Electronics Co., Ltd
• Original Assignee: Guangzhou On-Bright Electronics Co., Ltd
• Inventors: Fang, Lieyi, Lin, Guo Wei
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): DEMISSE, AFEWORK S
• Application Number:
  US15/054,032
• Publication Number:
  US 20160276939A1
• Time in Patent Office: 621 Days
• Field of Search: 363 2112, 363 2115, 363 49, 363 5612, 363 2117, 363 2118, 363 80, 363 79, 363 2101
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33515 with digital control
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

System and method for regulating a power converter. The system includes a first signal processing component configured to receive at least a sensed signal and generate a first signal. The sensed signal is associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter. Additionally, the system includes a second signal processing component configured to generate a second signal, an integrator component configured to receive the first signal and the second signal and generate a third signal, and a comparator configured to process information associated with the third signal and the sensed signal and generate a comparison signal based on at least information associated with the third signal and the sensed signal.

Claims

1. A system for regulating a power converter, the system comprising:

a voltage-to-current-conversion component configured to generate a first current signal;

a current-signal generator configured to generate a second current signal;

a capacitor coupled to the current-signal generator and coupled, through a switch, to the voltage-to-current-conversion component, the capacitor being configured to generate a voltage signal;

a comparator configured to process information associated with the voltage signal and a sensed signal and generate a comparison signal based on at least information associated with the voltage signal and the sensed signal, the sensed signal being associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter;

a modulation-signal generator configured to receive at least the comparison signal and generate a modulation signal; and

a gate driver configured to receive the modulation signal and output a drive signal to a switch, the switch being configured to affect the primary current flowing through the primary winding;

wherein the voltage-to-current-conversion component is further configured to process information associated with the voltage signal and generate the first current signal based on at least information associated with the voltage signal;

wherein;

the drive signal is associated with at least one or more switching periods, each switching period of the one or more switching periods including at least an on-time period for the switch and a demagnetization period for a demagnetization process; and

the first current signal represents the primary current at the end of the on-time period;

wherein for each switching period of the one or more switching periods,

the first current signal discharges or charges the capacitor during only the demagnetization period;

the second current signal charges or discharges the capacitor during the switching period; and

the switching period multiplied by the second current signal is equal to the demagnetization period multiplied by the first current signal in magnitude.

2. The system of claim 1, and further comprising a low-pass filter coupled, directly or indirectly, to the capacitor, the comparator, and the voltage-to-current-conversion component.

3. The system of claim 1 wherein:

the voltage-to-current-conversion component, the current-signal generator, the comparator, the modulation-signal generator, and the gate driver are located on a chip; and

the capacitor is located on or off the chip.

4. The system of claim 1 is configured to regulate an output current at a predetermined constant level in a quasi-resonant mode.

5. The system of claim 1, and further comprising a pulse-signal generator configured to output one or more signal pulses to the modulation-signal generator in response to one or more demagnetization pulses corresponding to one or more demagnetization periods.

6. A method for regulating a power converter, the method comprising:

generating a first current signal and a second current signal;

processing information associated with the first current signal and the second current signal;

generating a voltage signal, by at least a capacitor, based on at least information associated with the first current signal and the second current signal;

processing information associated with the voltage signal and a sensed signal, the sensed signal being associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter;

generating a comparison signal based on at least information associated with the voltage signal and the sensed signal;

receiving at least the comparison signal;

generating a modulation signal based on at least information associated with the comparison signal;

receiving the modulation signal; and

outputting a drive signal based on at least information associated with the modulation signal to affect the primary current flowing through the primary winding;

wherein the process for generating a first current signal and a second current signal includes processing information associated with the voltage signal and generating the first current signal based on at least information associated with the voltage signal;

wherein;

the drive signal is associated with at least one or more switching periods, each switching period of the one or more switching periods including at least an on-time period and a demagnetization period; and

the first current signal represents the primary current at the end of the on-time period;

wherein for each switching period of the one or more switching periods, the process for processing information associated with the first current signal and the second current signal includes;

discharging or charging the capacitor with the first current signal during only the demagnetization period; and

charging or discharging the capacitor with the second current signal during the switching period;

wherein the switching period multiplied by the second current signal is equal to the demagnetization period multiplied by the first current signal in magnitude.

7. A system for regulating a power converter, the system comprising:

a first sampling-and-holding and voltage-to-current-conversion component configured to receive at least a sensed signal and generate a first current signal, the sensed signal being associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter;

a second sampling-and-holding and voltage-to-current-conversion component configured to receive at least the sensed signal and generate a second current signal;

a current-signal generator configured to generate a third current signal;

a capacitor coupled to the current-signal generator and coupled, through a switch, to the first sampling-and-holding and voltage-to-current-conversion component and the second sampling-and-holding and voltage-to-current-conversion component, the capacitor being configured to generate a voltage signal;

a comparator configured to process information associated with the voltage signal and a ramping signal and generate a comparison signal based on at least information associated with the voltage signal and the ramping signal;

a modulation-signal generator configured to receive at least the comparison signal and generate a modulation signal; and

a gate driver configured to receive the modulation signal and output a drive signal to a switch, the switch being configured to affect the primary current flowing through the primary winding;

wherein;

the drive signal is associated with at least a plurality of switching periods, each switching period of the plurality of switching periods including at least an on-time period for the switch and a demagnetization period for a demagnetization process;

the first current signal represents the primary current at the beginning of the on-time period; and

the second current signal represents the primary current at the end of the on-time period;

wherein for each switching period of the plurality of switching periods,

the first current signal and the second current signal discharge or charge the capacitor during only the demagnetization period; and

the third current signal charges or discharges the capacitor during the switching period;

wherein over the plurality of switching periods, accumulatively, the switching period multiplied by the third current signal is equal to the demagnetization period multiplied by a sum of the first current signal and the second current signal in magnitude.

8. The system of claim 7, and further comprising a low-pass filter coupled, directly or indirectly, to the capacitor and the comparator.

9. The system of claim 7 wherein:

the first sampling-and-holding and voltage-to-current-conversion component, the second sampling-and-holding and voltage-to-current-conversion component, the current-signal generator, the comparator, the modulation-signal generator, and the gate driver are located on a chip; and

the capacitor is located on or off the chip.

10. The system of claim 7 is configured to regulate an output current at a predetermined constant level in a discontinuous conduction mode and a continuous conduction mode.

11. The system of claim 10 is further configured to achieve a power factor that is equal to or larger than 0.9 in the discontinuous conduction mode and the continuous conduction mode.

12. The system of claim 7 is configured to regulate an output current at a predetermined constant level in a discontinuous conduction mode.

13. The system of claim 12 is further configured to achieve a power factor that is equal to or larger than 0.9 in the discontinuous conduction mode.

14. The system of claim 7 is configured to regulate an output current at a predetermined constant level in a continuous conduction mode.

15. The system of claim 14 is further configured to achieve a power factor that is equal to or larger than 0.9 in the continuous conduction mode.

16. The system of claim 7 wherein the on-time period is constant.

17. The system of claim 7, and further comprising a ramping signal generator configured to generate the ramping signal.

18. A method for regulating a power converter, the method comprising:

receiving at least a sensed signal, the sensed signal being associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter;

processing information associated with the sensed signal;

generating a first current signal and a second current signal based on at least information associated with the sensed signal;

generating a third current signal;

processing information associated with the first current signal, the second current signal and the third current signal;

generating a voltage signal, by at least a capacitor, based on at least information associated with the first current signal, the second current signal and the third current signal;

processing information associated with the voltage signal and a ramping signal;

generating a comparison signal based on at least information associated with the voltage signal and the ramping signal;

receiving at least the comparison signal;

generating a modulation signal based on at least information associated with the comparison signal;

receiving the modulation signal; and

outputting a drive signal based on at least information associated with the modulation signal to affect the primary current flowing through the primary winding;

wherein;

the drive signal is associated with at least a plurality of switching periods, each switching period of the plurality of switching periods including at least an on-time period and a demagnetization period;

the first current signal represents the primary current at the beginning of the on-time period; and

the second current signal represents the primary current at the end of the on-time period;

wherein for each switching period of the plurality of switching periods, the process for processing information associated with the first current signal, the second current signal and the third current signal includes;

discharging or charging the capacitor with the first current signal and the second current signal during only the demagnetization period; and

charging or discharging the capacitor with the third current signal during the switching period;

wherein over the plurality of switching periods, accumulatively, the switching period multiplied by the third current signal is equal to the demagnetization period multiplied by a sum of the first current signal and the second current signal in magnitude.

19. A system for regulating a power converter, the system comprising:

a voltage-to-current-conversion component configured to generate a first current signal;

a current-signal generator configured to generate a second current signal;

a capacitor coupled to the current-signal generator and coupled, through a switch, to the voltage-to-current-conversion component, the capacitor being configured to generate a voltage signal;

a multiplier component configured to process information associated with the voltage signal and an input signal and generate a multiplication signal based on at least information associated with the voltage signal and the input signal, the input signal being related to a primary winding;

a comparator configured to receive the multiplication signal and a sensed signal and generate a comparison signal based on at least information associated with the multiplication signal and the sensed signal;

a modulation-signal generator configured to receive at least the comparison signal and generate a modulation signal; and

a gate driver configured to receive the modulation signal and output a drive signal to a switch, the switch being configured to affect a primary current flowing through the primary winding;

wherein the voltage-to-current-conversion component is further configured to process information associated with the multiplication signal and generate the first current signal based on at least information associated with the multiplication signal;

wherein;

the drive signal is associated with at least a plurality of switching periods, each switching period of the plurality of switching periods including at least an on-time period for the switch and a demagnetization period for a demagnetization process; and

the first current signal represents the primary current at the end of the on-time period;

wherein for each switching period of the plurality of switching periods,

the first current signal discharges or charges the capacitor during only the demagnetization period; and

the second current signal charges or discharges the capacitor during the switching period;

wherein over the plurality of switching periods, accumulatively, the switching period multiplied by the second current signal is equal to the demagnetization period multiplied by the first current signal in magnitude.

20. The system of claim 19, and further comprising a low-pass filter coupled, directly or indirectly, to the capacitor and the multiplier component.

21. The system of claim 19 wherein:

the voltage-to-current-conversion component, the current-signal generator, the multiplier component, the comparator, the modulation-signal generator, and the gate driver are located on a chip; and

the capacitor is located on or off the chip.

22. The system of claim 19 is configured to regulate an output current at a predetermined constant level in a quasi-resonant mode.

23. The system of claim 22 is further configured to achieve a power factor that is equal to or larger than 0.9 in the quasi-resonant mode.

24. The system of claim 19, and further comprising a pulse-signal generator configured to output one or more signal pulses to the modulation-signal generator in response to one or more demagnetization pulses corresponding to one or more demagnetization periods.

25. A method for regulating a power converter, the method comprising:

generating a first current signal and a second current signal;

processing information associated with the first current signal and the second current signal;

generating a voltage signal, by at least a capacitor, based on at least information associated with the first current signal and the second current signal;

processing information associated with the voltage signal and an input signal, the input signal being related to a primary winding;

generating a multiplication signal based on at least information associated with the voltage signal and the input signal;

receiving the multiplication signal and a sensed signal;

generating a comparison signal based on at least information associated with the multiplication signal and the sensed signal;

receiving at least the comparison signal;

generating a modulation signal based on at least information associated with the comparison signal;

receiving the modulation signal; and

outputting a drive signal based on at least information associated with the modulation signal to affect a primary current flowing through the primary winding;

wherein the process for generating a first current signal and a second current signal includes processing information associated with the multiplication signal and generating the first current signal based on at least information associated with the multiplication signal;

wherein;

the drive signal is associated with at least a plurality of switching periods, each switching period of the plurality of switching periods including at least an on-time period and a demagnetization period; and

the first current signal represents the primary current at the end of the on-time period;

wherein for each switching period of the plurality of switching periods, the process for processing information associated with the first current signal and the second current signal includes;

discharging or charging the capacitor with the first current signal during only the demagnetization period; and

charging or discharging the capacitor with the second current signal during the switching period;

wherein over the plurality of switching periods, accumulatively, the switching period multiplied by the second current signal is equal to the demagnetization period multiplied by the first current signal in magnitude.