This application claims priority to Chinese Patent Application No. 201110103130.4, filed Apr. 22, 2011, commonly assigned, incorporated by reference herein for all purposes.
The present invention is directed to integrated circuits. More particularly, the invention provides systems and methods for dimming control. Merely by way of example, the invention has been applied for dimming control using a light dimmer with capacitive loads. But it would be recognized that the invention has a much broader range of applicability.
Light emitting diodes (LEDs) have been widely used in various electronics applications, such as architectural lighting, automotive lighting, and backlighting of liquid crystal display (LCD). LEDs have been recognized to have significant advantages over other lighting sources, such as incandescent lamps, and the advantages include at least high efficiency and long lifetime. But, significant challenges remain for LEDs to widely replace incandescent lamps. The LED light systems need to be made compatible with conventional light dimmers that often operate with a phase-cut dimming method, such as leading edge dimming or trailing edge dimming.
Specifically, a conventional light dimmer usually includes a Triode for Alternating Current (TRIAC), and is used to drive pure resistive loads, such as incandescent lamps. But such conventional light dimmer may not function properly when connected to capacitive loads, such as LEDs and/or associated circuits. When the light dimmer starts conduction, internal inductance of the light dimmer and the capacitive loads may cause low frequency oscillation. Hence, the Alternate Current (AC) waveforms of the light dimmer often becomes unstable, resulting in flickering, undesirable audible noise, and/or even damages to other system components.
In attempt to solve the above problems in using a conventional light dimmer with capacitive loads such as LEDs and/or associated circuits, a power resistor (e.g., with a resistance of several hundred Ohms) may be connected in series in an AC loop to dampen initial current surge when the light dimmer starts conduction.
Therefore, some conventional techniques would short the power resistor through peripheral circuits when the AC input is stabilized after a light dimmer conducts for a predetermined period of time.
But the system 400 still suffers from significant deficiencies. For example, in a BUCK topology, when the TRIAC is turned off, the voltage on the capacitor 430 may not become lower than the output voltage (e.g., VOUT) at output terminals 452 and 454. If the output voltage and/or the threshold voltage of the transistor 460 changes, the transistor 460 may not be turned off properly and thus the resistor 478 may always be shorted. Thus, the system 400 would not operate properly under these circumstances.
Hence it is highly desirable to improve techniques of dimming control.
The present invention is directed to integrated circuits. More particularly, the invention provides systems and methods for dimming control. Merely by way of example, the invention has been applied for dimming control using a light dimmer with capacitive loads. But it would be recognized that the invention has a much broader range of applicability.
According to one embodiment, a system for dimming control includes a system controller including a first controller terminal and a second controller terminal, a transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal, and a resistor including a first resistor terminal and a second resistor terminal. The system controller is configured to generate a first signal at the first controller terminal based on at least information associated with an input signal and to generate a second signal at the second controller terminal based on at least information associated with the first signal. Moreover, the first transistor terminal is coupled, directly or indirectly, to the second controller terminal. The second transistor terminal is biased at a first voltage. Additionally, the first resistor terminal is coupled to the second transistor terminal, and the second resistor terminal is coupled to the third transistor terminal. Furthermore, the transistor is configured to receive the second signal at the first transistor terminal and to change between a first condition and a second condition in response to the second signal. The first signal is at a first logic level during a first period of time and changes between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. Additionally, the second signal keeps at the second logic level during the first period of time and the third period of time, and the second signal changes from the second logic level to the first logic level after the third period of time and remains at the first logic level during the fourth period of time.
According to another embodiment, a system for dimming control includes a system controller including a first controller terminal, a second controller terminal, and a third controller terminal, a first transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal, and a first resistor including a first resistor terminal and a second resistor terminal. The system controller is configured to generate a first signal at the first controller terminal based on at least information associated with an input signal and to generate a second signal at the second controller terminal based on at least information associated with the first signal. Moreover, the first transistor terminal is coupled, directly or indirectly, to the second controller terminal. The second transistor terminal is coupled, directly or indirectly, to the third controller terminal, the third controller terminal being biased at a first voltage. Additionally, the first resistor terminal is coupled to the second transistor terminal, and the second resistor terminal is coupled to the third transistor terminal. Furthermore, the first transistor is configured to receive the second signal at the first transistor terminal and to change between a first condition and a second condition in response to the second signal.
According to yet another embodiment, a method for dimming control includes receiving an input signal, processing information associated with the input signal, and generating a first signal based on at least information associated with the input signal. Additionally, the method includes 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 at a transistor, and changing the transistor between a first condition and a second condition based on at least information associated with the second signal. The first signal is at a first logic level during a first period of time and changes between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. The second signal keeps at the second logic level during the first period of time and the third period of time. Additionally, the second signal changes from the second logic level to the first logic level after the third period of time and remains at the first logic level during the fourth period of time.
According to yet another embodiment, a system controller for dimming control includes a first controller terminal, a second controller terminal, and a third controller terminal. The system controller is configured to receive an input signal at the first controller terminal, generate a first signal at the second controller terminal based on at least information associated with the input signal, and process information associated with the first signal. Additionally, the system controller is configured to generate a second signal based on at least information associated with the first signal, and output the second signal at the third controller terminal. The first signal is at a first logic level during a first period of time and changes between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. The second signal keeps at the second logic level during the first period of time and the third period of time. Additionally, the second signal changes from the second logic level to the first logic level after the third period of time and remains at the first logic level during the fourth period of time.
According to yet another embodiment, a method for dimming control includes receiving an input signal, and generating a first signal based on at least information associated with the input signal, the first signal being at a first logic level during a first period of time and changing between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. Additionally, the method includes processing information associated with the first signal, generating a second signal based on at least information associated with the first signal, and outputting the second signal, the second signal keeping at the second logic level during the first period of time and the third period of time, the second signal changing from the second logic level to the first logic level after the third period of time and remaining at the first logic level during the fourth period of time.
Many benefits are achieved by way of the present invention over conventional techniques. For example, some embodiments of the present invention provide an input signal of which each period includes a first part and a second part. As an example, during the first part, the input signal changes with time in magnitude, and during the second part, the input signal does not change with time in magnitude. In another example, the input signal is generated by a TRIAC. Certain embodiments of the present invention provide a system controller configured to generate a first signal at a first logic level during a first period of time and to change the first signal between the first logic level and a second logic level during a second period of time. Some embodiments of the present invention provide a system controller including a sensing component configured to receive a first signal and to generate a logic signal based on at least information associated with the first signal, and a control and driver component configured to detect the logic signal and to generate a second signal based on at least information associated with the logic signal. Certain embodiments of the present invention provide one or more transistors to be used for dimming control. For example, a transistor is configured to be turned on under a first condition in response to a signal, and to be turned off under a second condition in response to the signal. In yet another example, two first transistors are configured to be turned on under a first condition in response to a signal in order to turn off a second transistor. In another example, the two first transistors are configured to be turned off under a second condition in response to the signal in order to turn on the second transistor.
Depending upon embodiment, one or more benefits may be achieved. These benefits and various additional objects, features and advantages of the present invention can be fully appreciated with reference to the detailed description and accompanying drawings that follow.
The present invention is directed to integrated circuits. More particularly, the invention provides systems and methods for dimming control. Merely by way of example, the invention has been applied for dimming control using a light dimmer with capacitive loads. But it would be recognized that the invention has a much broader range of applicability.
According to one embodiment, a light dimmer (e.g., a TRIAC not shown in
According to one embodiment, the dimming control circuit 700 includes a system controller 720, a transistor 730, and a resistor 740. For example, the dimming control circuit 700 is used as the dimming control circuit 520. In another example, the system controller 720, the transistor 730, and the resistor 740 are the same as the system controller 530, the transistor 540, and the resistor 550, respectively. In yet another example, the system controller 720 is the same as the system controller 600. In yet another example, the transistor 730 is a field effect transistor (FET), such as an N-channel FET. In yet another example, the system controller 720 includes a terminal 750 (e.g., a GND terminal), a terminal 752 (e.g., a VDD terminal), a terminal 754 (e.g., a GATE terminal), a terminal 756 (e.g., a TRIAC terminal), and a terminal 758 (e.g., a VIN terminal).
According to another embodiment, the resistor 740 is coupled in parallel with the transistor 730. A terminal 742 of the resistor 740 is biased to an on-chip ground of the system controller 720. For example, the terminal 742 is connected to the terminal 750 of the system controller 720 (e.g., the GND terminal). In another example, the voltage of the on-chip ground of the system controller 720 may change with time. In another example, another terminal 744 of the resistor 740 is biased to the ground (e.g., an off-chip ground and/or an external ground).
Although the above has been shown using a selected group of components for the circuit 700, there can be many alternatives, modifications, and variations. For example, some of the components may be expanded and/or combined. Other components may be inserted to those noted above. For example, the dimming control circuit 700 also includes two additional transistors 760 and 770. These transistors may be bipolar transistors, such as N-P-N and/or P-N-P bipolar transistors.
As an example, a terminal 762 of the transistor 760 is coupled, directly or indirectly through a resistor 780, to the terminal 752 of the system controller 720 (e.g., the VDD terminal). For example, the internal circuit supply voltage of the terminal 752 may change with time. In another example, a terminal 764 of the transistor 760 is coupled directly or indirectly through a resistor 782, to the terminal 756 of the system controller 720 (e.g., the TRIAC terminal). In yet another example, a terminal 766 of the transistor 760 is coupled directly to a terminal 774 of the transistor 770. In yet another example, a terminal 772 of the transistor 770 is coupled directly to a terminal 732 of the transistor 730. In yet another example, a terminal 776 is biased to the ground. In yet another example, the terminal 772 is coupled indirectly through a resistor 784, to the terminal 776. In yet another example, the terminal 764 is coupled indirectly through a resistor 786, to the terminal 762. In yet another example, the terminal 764 is coupled indirectly through the resistor 782 and a resistor 788, to the terminal 732.
According to one embodiment, before a light dimmer (e.g., a TRIAC not shown in
In one embodiment, in response to an input signal at the terminal 758 (e.g., the VIN terminal), the system controller 720 changes the gate signal 790 from being at the logic high level to being a pulse signal that changes between the logic high level and the logic low level. In the meantime, the dimming control signal 792 remains at the logic low level in order to turn on the transistors 760 and 770. Hence, according to one embodiment, the transistor 730 remains off and the resistor 740 is used to dampen any initial surge current to one or more capacitive loads. After a predetermined period of time, the system controller 720 changes the dimming control signal from the logic low level to the logic high level, causing the transistors 760 and 770 to be turned off In response, the transistor 730 is turned on and the resistor 740 is shorted to improve system efficiency according to one embodiment. For example, the predetermined period of time is equal to one or more periods (e.g., 4, 6, 8, or 10 periods) of the pulse signal for the gate signal 790.
As shown in
According to one embodiment, between t0 and t1, the input signal 510 (corresponding to the curve 804) is constant in magnitude. During this period of time, the gate signal 790 (corresponding to the curve 806) keeps at the logic high level, and the dimming control signal 792 (corresponding to the curve 808) keeps at the logic low level.
According to anther embodiment, at t1, the input signal 510 (corresponding to the curve 804) starts changing with time in magnitude. In response, the gate signal 790 (corresponding to the curve 806) becomes a pulse signal. During the period of time between t1 and t2, the dimming control signal 792 (corresponding to the curve 808) remains at the logic low level. For example, during this period of time, the transistor 730 is turned off and the resistor 740 is used to dampen any initial surge current. In another example, the period of time between t1 and t2 equals one or more periods (e.g., 4, 6, 8, or 10 periods) of the pulse signal for the gate signal 790. After t2, the dimming control signal 792 (corresponding to the curve 808) rises from the logic low level to the logic high level, and then remains at the logic high level for a period of time according to one embodiment. In response, the transistor 730 is turned on and thus the resistor 740 is shorted.
As shown in
According to one embodiment, when the input signal 510 (corresponding to the curve 904) is constant in magnitude, the output current 560 (corresponding to the curve 902) decreases with time. According to another embodiment, when the input signal 510 (corresponding to the curve 904) changes with time in magnitude, the output current 560 (corresponding to the curve 902) increases to a peak value and then decreases.
As shown in
According to one embodiment, a light dimmer (e.g., a TRIAC not shown in
In one embodiment, the gate sense module 1110 receives a gate signal 1131 (e.g., the gate signal 790), and transforms the gate signal 1131 to an internal logic signal 1112 (e.g., the GS signal). For example, the gate signal 1131 is received and used by one or more components that are internal to the system controller 1100. In another embodiment, the control module 1120 detects the logic signal 1112 and in response generates a signal 1122 (e.g., the Tri signal). In yet another embodiment, the driver module 1130 receives the signal 1122 and outputs a dimming control signal 1132 (e.g., the dimming control signal 792).
According to another embodiment, a system for dimming control includes a system controller including a first controller terminal and a second controller terminal, a transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal, and a resistor including a first resistor terminal and a second resistor terminal. The system controller is configured to generate a first signal at the first controller terminal based on at least information associated with an input signal and to generate a second signal at the second controller terminal based on at least information associated with the first signal. Moreover, the first transistor terminal is coupled, directly or indirectly, to the second controller terminal. The second transistor terminal is biased at a first voltage. Additionally, the first resistor terminal is coupled to the second transistor terminal, and the second resistor terminal is coupled to the third transistor terminal. Furthermore, the transistor is configured to receive the second signal at the first transistor terminal and to change between a first condition and a second condition in response to the second signal. The first signal is at a first logic level during a first period of time and changes between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. Additionally, the second signal keeps at the second logic level during the first period of time and the third period of time, and the second signal changes from the second logic level to the first logic level after the third period of time and remains at the first logic level during the fourth period of time. For example, the system is implemented according to at least
According to another embodiment, a system for dimming control includes a system controller including a first controller terminal, a second controller terminal, and a third controller terminal, a first transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal, and a first resistor including a first resistor terminal and a second resistor terminal. The system controller is configured to generate a first signal at the first controller terminal based on at least information associated with an input signal and to generate a second signal at the second controller terminal based on at least information associated with the first signal. Moreover, the first transistor terminal is coupled, directly or indirectly, to the second controller terminal. The second transistor terminal is coupled, directly or indirectly, to the third controller terminal, the third controller terminal being biased at a first voltage. Additionally, the first resistor terminal is coupled to the second transistor terminal, and the second resistor terminal is coupled to the third transistor terminal. Furthermore, the first transistor is configured to receive the second signal at the first transistor terminal and to change between a first condition and a second condition in response to the second signal. For example, the system is implemented according to at least
According to yet another embodiment, a method for dimming control includes receiving an input signal, processing information associated with the input signal, and generating a first signal based on at least information associated with the input signal. Additionally, the method includes 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 at a transistor, and changing the transistor between a first condition and a second condition based on at least information associated with the second signal. The first signal is at a first logic level during a first period of time and changes between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. The second signal keeps at the second logic level during the first period of time and the third period of time. Additionally, the second signal changes from the second logic level to the first logic level after the third period of time and remains at the first logic level during the fourth period of time. For example, the method is performed according to at least
According to yet another embodiment, A system controller for dimming control includes a first controller terminal, a second controller terminal, and a third controller terminal. The system controller is configured to receive an input signal at the first controller terminal, generate a first signal at the second controller terminal based on at least information associated with the input signal, and process information associated with the first signal. Additionally, the system controller is configured to generate a second signal based on at least information associated with the first signal, and output the second signal at the third controller terminal. The first signal is at a first logic level during a first period of time and changes between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. The second signal keeps at the second logic level during the first period of time and the third period of time. Additionally, the second signal changes from the second logic level to the first logic level after the third period of time and remains at the first logic level during the fourth period of time. For example, the system controller is implemented in at least
According to yet another embodiment, a method for dimming control includes receiving an input signal, and generating a first signal based on at least information associated with the input signal, the first signal being at a first logic level during a first period of time and changing between the first logic level and a second logic level during a second period of time, the second period of time including a third period of time and a fourth period of time. Additionally, the method includes processing information associated with the first signal, generating a second signal based on at least information associated with the first signal, and outputting the second signal, the second signal keeping at the second logic level during the first period of time and the third period of time, the second signal changing from the second logic level to the first logic level after the third period of time and remaining at the first logic level during the fourth period of time. For example, the method is performed in at least
Many benefits are achieved by way of the present invention over conventional techniques. For example, some embodiments of the present invention provide an input signal of which each period includes a first part and a second part. As an example, during the first part, the input signal changes with time in magnitude, and during the second part, the input signal does not change with time in magnitude. In another example, the input signal is generated by a TRIAC. Certain embodiments of the present invention provide a system controller configured to generate a first signal at a first logic level during a first period of time and to change the first signal between the first logic level and a second logic level during a second period of time. Some embodiments of the present invention provide a system controller including a sensing component configured to receive a first signal and to generate a logic signal based on at least information associated with the first signal, and a control and driver component configured to detect the logic signal and to generate a second signal based on at least information associated with the logic signal. Certain embodiments of the present invention provide one or more transistors to be used for dimming control. For example, a transistor is configured to be turned on under a first condition in response to a signal, and to be turned off under a second condition in response to the signal. In another example, two first transistors are configured to be turned on under a first condition in response to a signal in order to turn off a second transistor. In yet another example, the two first transistors are configured to be turned off under a second condition in response to the signal in order to turn on the second transistor.
For example, some or all components of various embodiments of the present invention each are, individually and/or in combination with at least another component, implemented using one or more software components, one or more hardware components, and/or one or more combinations of software and hardware components. In another example, some or all components of various embodiments of the present invention each are, individually and/or in combination with at least another component, implemented in one or more circuits, such as one or more analog circuits and/or one or more digital circuits. In yet another example, various embodiments and/or examples of the present invention can be combined.
Although specific embodiments of the present invention have been described, it will be understood by those of skill in the art that there are other embodiments that are equivalent to the described embodiments. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiments, but only by the scope of the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
2011 1 0103130 | Apr 2011 | CN | national |
Number | Name | Date | Kind |
---|---|---|---|
6218788 | Chen et al. | Apr 2001 | B1 |
7880400 | Zhou et al. | Feb 2011 | B2 |
8278832 | Hung et al. | Oct 2012 | B2 |
8378588 | Kuo et al. | Feb 2013 | B2 |
20070267978 | Shteynberg et al. | Nov 2007 | A1 |
20080278092 | Lys et al. | Nov 2008 | A1 |
20090021469 | Yeo et al. | Jan 2009 | A1 |
20090251059 | Veltman | Oct 2009 | A1 |
20100164406 | Kost et al. | Jul 2010 | A1 |
20110080111 | Nuhfer et al. | Apr 2011 | A1 |
Number | Date | Country |
---|---|---|
1448005 | Oct 2003 | CN |
101657057 | Feb 2010 | CN |
101917804 | Dec 2010 | CN |
101998734 | Mar 2011 | CN |
102014551 | Apr 2011 | CN |
102056378 | May 2011 | CN |
102300375 | Dec 2011 | CN |
102387634 | Mar 2012 | CN |
102695330 | Sep 2012 | CN |
2403318 | Jan 2012 | EP |
2011-249328 | Dec 2011 | JP |
201215228 | Sep 2010 | TW |
201125441 | Jul 2011 | TW |
201143530 | Dec 2011 | TW |
201146087 | Dec 2011 | TW |
201208463 | Feb 2012 | TW |
1448198 | Aug 2014 | TW |
Entry |
---|
Taiwan Intellectual Property Office, Office Action mailed Jan. 7, 2014, in Application No. 100119272. |
China Patent Office, Office Action mailed Jun. 3, 2014, in Application No. 201110103130.4. |
China Patent Office, Office Action mailed Jul. 7, 2014, in Application No. 201210468505.1. |
Taiwan Intellectual Property Office, Office Action mailed Jun. 9, 2014, in Application No. 101124982. |
China Patent Office, Office Action mailed Nov. 15, 2014, in Application No. 201210166672.0. |
Taiwan Intellectual Property Office, Office Action mailed Sep. 25, 2014, in Application No. 101148716. |
Number | Date | Country | |
---|---|---|---|
20120268031 A1 | Oct 2012 | US |