SYSTEMS AND METHODS FOR PEAK CURRENT ADJUSTMENTS IN POWER CONVERSION SYSTEMS

• US 20140160809A1
• Filed: 12/20/2012
• Published: 06/12/2014
• Est. Priority Date: 12/10/2012
• Status: Active Grant

• Current Assignee: On-Bright Electronics (Shanghai) Co., Ltd. (Orthosie Investment Holdings Ltd.)
• Original Assignee: On-Bright Electronics (Shanghai) Co., Ltd. (Orthosie Investment Holdings Ltd.)
• Inventors: Lin, Yuan, Zhang, Xiuhong, Fang, Lieyi, Wang, Weihua
• Granted Patent: US 9,379,624 B2
• Time in Patent Office: Days
• US Class Current: 363/21.16
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• 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 3/33515 with digital control
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• 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 an output of a power conversion system. An example system controller includes a signal generator and a modulation and drive component. The signal generator is configured to receive at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system and receive a second signal indicating a magnitude of a primary current flowing through the primary winding, and generate a third signal. The modulation and drive component is configured to receive at least the third signal, generate a drive signal based on at least information associated with the third signal, and output the drive signal to a switch to affect the primary current.

Claims

1. A system controller for regulating an output of a power conversion system, the system controller comprising:

a signal generator configured to receive at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system and receive a second signal indicating a magnitude of a primary current flowing through the primary winding, and generate a third signal; and

a modulation and drive component configured to receive at least the third signal, generate a drive signal based on at least information associated with the third signal, and output the drive signal to a switch to affect the primary current;

wherein the signal generator and the modulation and drive component are further configured to;

if an output voltage of the power conversion system is regulated in a constant-voltage mode and an output current of the power conversion system falls within a first predetermined range, generate a modulation signal as the drive signal based on at least information associated with the magnitude of the input voltage without taking into account the magnitude of the primary current flowing through the primary winding; and

if the output voltage is regulated in the constant-voltage mode and the output current falls within a second predetermined range, generate the modulation signal as the drive signal based on at least information associated with the magnitude of the primary current without taking into account the magnitude of the input voltage.

2. The system controller of claim 1 wherein the signal generator is further configured to:

if the output current is larger than a first threshold and smaller than a second threshold in magnitude, determine that the output current of the power conversion system falls within the first predetermined range; and

if the output current is larger than the second threshold and smaller than a third threshold in magnitude, determine that the output current falls within the second predetermined range.

3. The system controller of claim 2 wherein:

the modulation signal corresponds to a modulation frequency; and

the signal generator and the modulation and drive component are further configured to, if the output current is larger than the first threshold and smaller than the second threshold in magnitude, keep the modulation frequency at a predetermined frequency value if the output current increases and if the output voltage and the input voltage remain constant.

4. The system controller of claim 3 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the first threshold and smaller than the second threshold in magnitude, output the modulation signal to the switch so that a peak value of the primary current increase if the output current increases and if the output voltage and the input voltage remain constant.

5. The system controller of claim 4 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the second threshold and smaller than a fourth threshold in magnitude, increase the modulation frequency if the output current increases and if the output voltage and the input voltage remain constant, the fourth threshold being smaller than the third threshold in magnitude.

6. The system controller of claim 5 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the second threshold and smaller than the fourth threshold in magnitude, output the modulation signal to the switch so that the peak value of the primary current does not change if the output current increases and if the output voltage and the input voltage remain constant.

7. The system controller of claim 6 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the fourth threshold and smaller than a fifth threshold in magnitude, increase the modulation frequency if the output current increases and if the output voltage and the input voltage remain constant, the fifth threshold being smaller than the third threshold in magnitude.

8. The system controller of claim 7 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the fourth threshold and smaller than the fifth threshold in magnitude, output the modulation signal to the switch so that the peak value of the primary current increases if the output current increases and if the output voltage and the input voltage remain constant.

9. The system controller of claim 8 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the fifth threshold and smaller than the third threshold in magnitude, increase the modulation frequency if the output current increases and if the output voltage and the input voltage remain constant.

10. The system controller of claim 9 wherein the signal generator and the modulation and drive component are further configured to, if the output current is larger than the fifth threshold and smaller than the third threshold in magnitude, output the modulation signal to the switch so that the peak value of the primary current does not change if the output current increases and if the output voltage and the input voltage remain constant.

11. The system controller of claim 1 wherein the modulation and drive component includes:

a modulation component configured to receive at least the third signal and generate a fourth signal based on at least information associated with the third signal; and

a driving component configured to receive the fourth signal and output the drive signal to the switch based on at least information associated with the fourth signal.

12. The system controller of claim 1, and further comprising:

an error amplifier configured to receive at least a feedback signal of the power conversion system and generate an amplified signal based on at least information associated with the feedback signal; and

a signal processing component configured to receive the amplified signal and output a voltage signal to the signal generator based on at least information associated with the amplified signal.

13. The system controller of claim 1 wherein the signal generator includes:

a ramp-signal generator configured to receive at least the first signal, process information associated with the first signal, and generate a fourth signal based on at least information associated with the first signal;

a first comparator configured to receive the fourth signal and a fifth signal associated with a feedback signal of the power conversion system and generate a first comparison signal based on at least information associated with the fourth signal and the fifth signal; and

a second comparator configured to receive the fourth signal and a threshold signal and generate a second comparison signal based on at least information associated with the fourth signal and the threshold signal.

14. The system controller of claim 13 wherein the signal generator further includes a signal processor configured to receive the first comparison signal and the second comparison signal and generate the third signal based on at least information associated with the first comparison signal and the second comparison signal.

15. The system controller of claim 13 wherein the fourth signal is a ramp signal, the ramp signal including a signal pulse for each switching period corresponding to the drive signal.

16. The system controller of claim 1 wherein the modulation and drive component is further configured to output the drive signal to a bipolar junction transistor as the switch to affect the primary current.

17. The system controller of claim 1 wherein the modulation and drive component is further configured to output the drive signal to a metal-oxide-semiconductor field-effect transistor as the switch to affect the primary current.

18. The system controller of claim 1 wherein the modulation and drive component is further configured to output the drive signal to an insulated-gate bipolar transistor as the switch to affect the primary current.

19. A system controller for regulating an output of a power conversion system, the system controller comprising:

a signal generator configured to receive at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system, process information associated with the first signal, and generate a second signal based on at least information associated with the first signal; and

a modulation and drive component configured to receive at least the second signal, generate a drive signal based on at least information associated with the second signal, and output the drive signal to a switch to affect a primary current flowing through the primary winding;

wherein;

the signal generator and the modulation and drive component are further configured to, if an output voltage of the power conversion system is regulated in a constant-voltage mode and an output current of the power conversion system falls within a first predetermined range, generate a pulse-width-modulation signal corresponding to a pulse width and a modulation frequency as the drive signal; and

the pulse width decreases if the input voltage increases and if the output voltage and the output current remain constant.

20. The system controller of claim 19 wherein the signal generator and the modulation and drive component are further configured to, if the output voltage of the power conversion system is regulated in the constant-voltage mode and the output current of the power conversion system falls within the first predetermined range, generate the pulse-width-modulation signal corresponding to the pulse width and the modulation frequency as the drive signal, so that a peak value of the primary current increases if the output current increases and if the output voltage and the input voltage remain constant.

21. The system controller of claim 20 wherein the signal generator and the modulation and drive component are further configured to, if the output voltage of the power conversion system is regulated in the constant-voltage mode and the output current of the power conversion system falls within the first predetermined range, generate the pulse-width-modulation signal corresponding to the pulse width and the modulation frequency as the drive signal, so that a peak value of the primary current increases linearly if the output current increases and if the output voltage and the input voltage remain constant.

22. The system controller of claim 20 wherein the modulation frequency is constant with respect to the output current.

23. The system controller of claim 20 wherein the first signal is proportional to the magnitude of the input voltage.

24. The system controller of claim 20 wherein the signal generator is further configured to, if the output current is larger than a first threshold and smaller than a second threshold in magnitude, determine that the output current of the power conversion system falls within the first predetermined range.

25. The system controller of claim 19 wherein the signal generator and the modulation and drive component are further configured to, if an output voltage of the power conversion system is regulated in the constant-voltage mode and the output current of the power conversion system falls within the first predetermined range, generate the pulse-width-modulation signal as the drive signal based on at least information associated with the magnitude of the input voltage without taking into account the magnitude of the primary current flowing through the primary winding.

26. The system controller of claim 25 wherein the signal generator and the modulation and drive component are further configured to, if the output voltage is regulated in the constant-voltage mode and the output current falls within a second predetermined range, generate the pulse-width-modulation signal as the drive signal based on at least information associated with the magnitude of the primary current without taking into account the magnitude of the input voltage.

27. The system controller of claim 26 wherein the signal generator is further configured to, if the output current is larger than the second threshold and smaller than a third threshold in magnitude, determine that the output current of the power conversion system falls within the second predetermined range.

28. The system controller of claim 19 wherein the signal generator includes:

a ramp-signal generator configured to receive at least the first signal, process information associated with the first signal, and generate a third signal based on at least information associated with the first signal;

a first comparator configured to receive the third signal and a fourth signal associated with a feedback signal of the power conversion system and generate a first comparison signal based on at least information associated with the third signal and the fourth signal; and

a second comparator configured to receive the third signal and a threshold signal and generate a second comparison signal based on at least information associated with the third signal and the threshold signal.

29. The system controller of claim 28 wherein the signal generator further includes a signal processor configured to receive the first comparison signal and the second comparison signal and generate the second signal based on at least information associated with the first comparison signal and the second comparison signal.

30. The system controller of claim 28 wherein the third signal is a ramp signal, the ramp signal including a signal pulse for each switching period corresponding to the drive signal.

31. The system controller of claim 19 wherein the modulation and drive component is further configured to output the drive signal to a bipolar junction transistor as the switch to affect the primary current.

32. The system controller of claim 19 wherein the modulation and drive component is further configured to output the drive signal to a metal-oxide-semiconductor field-effect transistor as the switch to affect the primary current.

33. The system controller of claim 19 wherein the modulation and drive component is further configured to output the drive signal to an insulated-gate bipolar transistor as the switch to affect the primary current.

34. A system controller for regulating an output of a power conversion system, the system controller comprising:

a signal generator configured to receive at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system, process information associated with the first signal, and generate a second signal based on at least information associated with the first signal;

a first comparator configured to receive the second signal and a third signal associated with a feedback signal of the power conversion system and generate a first comparison signal based on at least information associated with the second signal and the third signal;

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

a modulation and drive component configured to receive at least the first comparison signal and the second comparison signal, generate a drive signal based on at least information associated with the first comparison signal and the second comparison signal, and output the drive signal to a switch to affect a primary current flowing through the primary winding;

wherein the modulation and drive component is further configured to;

if the third signal is larger than the threshold signal in magnitude, output the drive signal to close the switch if the second signal is smaller than the third signal; and

if the threshold signal is larger than the third signal in magnitude, output the drive signal to close the switch if the second signal is smaller than the threshold signal.

35. The system controller of claim 34 wherein the second signal is a ramp signal, the ramp signal including a signal pulse for each switching period corresponding to the drive signal.

36. The system controller of claim 34 wherein the first comparator is further configured to receive the third signal associated with an amplified signal generated by an error amplifier based on at least information associated with the feedback signal of the power conversion system.

37. The system controller of claim 34 wherein:

the modulation and drive component includes an OR gate configured to receive the first comparison signal and the second comparison signal and generate a logic signal; and

the modulation and drive component is further configured to generate the drive signal based on at least information associated with the logic signal.

38. The system controller of claim 34 wherein:

the modulation and drive component is further configured to output the drive signal to the signal generator; and

the signal generator is further configured to process information associated with the drive signal, and generate the second signal based on at least information associated with the first signal and the drive signal.

39. The system controller of claim 34 wherein the modulation and drive component includes:

a signal processor configured to receive the first comparison signal and the second comparison signal and generate a first processed signal based on at least information associated with the first comparison signal and the second comparison signal;

a modulation component configured to receive at least the first processed signal and generate a modulation signal based on at least information associated with the first processed signal; and

a driving component configured to receive the modulation signal and generate the drive signal.

40. The system controller of claim 39 wherein the signal processor includes:

a first OR gate configured to receive the first comparison signal and the second comparison signal and generate a second processed signal based on at least information associated with the first comparison signal and the second comparison signal; and

a second OR gate configured to receive the second processed signal and a first leading-edge-blanking signal associated with a leading-edge-blanking period and generate the first processed signal based on at least information associated with the second processed signal and the first leading-edge-blanking signal.

41. The system controller of claim 40, and further comprising:

a leading-edge-blanking component configured to receive a second leading-edge-blanking signal associated with the leading-edge-blanking period and a current sensing signal associated with the primary current flowing through the primary winding and generate a third processed signal based on at least information associated with the second leading-edge-blanking signal and the current sensing signal; and

a third comparator configured to receive a fourth signal associated with the feedback signal of the power conversion system and a fifth signal associated with the third processed signal and generate a third comparison signal based on at least information associated with the fourth signal and the fifth signal.

42. The system controller of claim 41, and further comprising a third OR gate configured to receive the third comparison signal and the second leading-edge-blanking signal and output a fourth processed signal to the modulation and drive component.

43. The system controller of claim 42 wherein during the leading-edge-blanking period, the first leading-edge-blanking signal is at a logic high level and the second leading-edge-blanking signal is at a logic low level.

44. The system controller of claim 34 wherein the signal generator includes:

a capacitor configured to receive the first signal and generate the second signal; and

a switching component configured to be closed or open in response to a switching signal;

wherein;

if the switching component is open, the capacitor is configured to be charged in response to the first signal; and

if the switching component is closed, the capacitor is configured to be discharged through the switching component.

45. The system controller of claim 34 wherein the modulation and drive component is further configured to output the drive signal to a bipolar junction transistor as the switch to affect the primary current.

46. The system controller of claim 34 wherein the modulation and drive component is further configured to output the drive signal to a metal-oxide-semiconductor field-effect transistor as the switch to affect the primary current.

47. The system controller of claim 34 wherein the modulation and drive component is further configured to output the drive signal to an insulated-gate bipolar transistor as the switch to affect the primary current.

48. A method for regulating an output of a power conversion system, the method comprising:

receiving at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system;

receiving a second signal indicating a magnitude of a primary current flowing through the primary winding;

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

generating a third signal;

receiving at least the third signal;

processing information associated with the third signal;

generating a drive signal based on at least information associated with the third signal; and

outputting the drive signal to a switch to affect the primary current;

wherein the process for generating a drive signal based on at least information associated with the third signal includes;

if an output voltage of the power conversion system is regulated in a constant-voltage mode and an output current of the power conversion system falls within a first predetermined range, generating a modulation signal as the drive signal based on at least information associated with the magnitude of the input voltage without taking into account the magnitude of the primary current flowing through the primary winding; and

if the output voltage is regulated in the constant-voltage mode and the output current falls within a second predetermined range, generating the modulation signal as the drive signal based on at least information associated with the magnitude of the primary current without taking into account the magnitude of the input voltage.

49. A method for regulating an output of a power conversion system, the method comprising:

receiving at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system;

processing information associated with the first signal;

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

receiving at least the second signal;

processing information associated with the second signal;

generating a drive signal based on at least information associated with the second signal; and

outputting the drive signal to a switch to affect a primary current flowing through the primary winding;

wherein;

the process for generating a drive signal based on at least information associated with the second signal includes, if an output voltage of the power conversion system is regulated in a constant-voltage mode and an output current of the power conversion system falls within a first predetermined range, generating a pulse-width-modulation signal corresponding to a pulse width and a modulation frequency as the drive signal; and

the pulse width decreases if the input voltage increases and if the output voltage and the output current remain constant.

50. A method for regulating an output of a power conversion system, the method comprising:

receiving at least a first signal indicating a magnitude of an input voltage received by a primary winding of a power conversion system;

processing information associated with the first signal;

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

receiving the second signal and a third signal associated with a feedback signal of the power conversion system;

processing information associated with the second signal and the third signal;

generating a first comparison signal based on at least information associated with the second signal and the third signal;

receiving the second signal and a threshold signal;

processing information associated with the second signal and the threshold signal;

generating a second comparison signal based on at least information associated with the second signal and the threshold signal;

receiving at least the first comparison signal and the second comparison signal;

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

generating a drive signal based on at least information associated with the first comparison signal and the second comparison signal; and

outputting the drive signal to a switch to affect a primary current flowing through the primary winding;

wherein the process for outputting the drive signal to a switch to affect a primary current flowing through the primary winding includes;

if the third signal is larger than the threshold signal in magnitude, outputting the drive signal to close the switch if the second signal is smaller than the third signal; and

if the threshold signal is larger than the third signal in magnitude, outputting the drive signal to close the switch if the second signal is smaller than the threshold signal.