TWI847604B - Circuit for measuring the supply voltage of the power supply terminal of LED control chip - Google Patents
Circuit for measuring the supply voltage of the power supply terminal of LED control chip Download PDFInfo
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Abstract
本發明提供一種用於發光二極體(Light-emitting diode,LED)控制晶片的測量供電端的供電電壓的電路。供電端經由LED控制晶片的高壓引腳向連接到LED控制晶片的電源引腳的儲能器件供電,以使得儲能器件經由電源引腳向LED控制晶片提供工作電流,該電路包括:第一控制單元,連接在高壓引腳與電源引腳之間,用於根據第一控制信號接通或斷開高壓引腳與電源引腳之間的連接;電壓測量單元,連接在高壓引腳與參考地之間,用於根據第二控制信號開啟或停止經由高壓引腳對供電電壓的測量,在第一控制單元接通高壓引腳與電源引腳之間的連接的情況下,電壓測量單元停止對供電電壓的測量;在第一控制單元斷開高壓引腳與電源引腳之間的連接的情況下,電壓測量單元開啟對供電電壓的測量。 The present invention provides a circuit for measuring the power supply voltage of a power supply terminal of a light-emitting diode (LED) control chip. The power supply terminal supplies power to an energy storage device connected to a power supply pin of the LED control chip via a high-voltage pin of the LED control chip, so that the energy storage device provides a working current to the LED control chip via the power supply pin. The circuit includes: a first control unit connected between the high-voltage pin and the power supply pin, and used to connect or disconnect the connection between the high-voltage pin and the power supply pin according to a first control signal; a voltage measuring unit, Connected between the high voltage pin and the reference ground, it is used to start or stop the measurement of the power supply voltage through the high voltage pin according to the second control signal. When the first control unit connects the connection between the high voltage pin and the power supply pin, the voltage measurement unit stops measuring the power supply voltage; when the first control unit disconnects the connection between the high voltage pin and the power supply pin, the voltage measurement unit starts measuring the power supply voltage.
Description
本發明涉及電路領域,特別是,涉及一種用於LED控制晶片的測量供電端的供電電壓的電路。 The present invention relates to the field of circuits, and in particular, to a circuit for measuring the power supply voltage of a power supply terminal of an LED control chip.
LED照明已成為人們日常生活中不可或缺的一部分,因而用於為LED供電的LED驅動電路的使用日益廣泛。 LED lighting has become an integral part of people's daily lives, and as a result, LED driver circuits used to power LEDs are becoming increasingly popular.
LED驅動電路通常在LED控制晶片的控制下將外部供電電流轉換為恆定電流來為LED供電。LED控制晶片需要使用供電端的供電電壓為連接到LED控制晶片的電源引腳的儲能器件供電,以使得儲能器件能夠為LED控制晶片提供工作電流。為實現對LED控制晶片的諸如過壓保護等的相關控制,需要對該供電端的供電電壓進行測量。然而,供電電壓的測量通常會受到LED驅動晶片的工作狀態的影響,而導致測量結果不準確,從而影響LED控制晶片的相關控制操作,甚至會對LED控制晶片造成安全隱患。 LED driver circuits usually convert external power supply current into constant current to power LEDs under the control of LED control chips. LED control chips need to use the power supply voltage at the power supply end to power the energy storage device connected to the power pin of the LED control chip, so that the energy storage device can provide working current for the LED control chip. In order to achieve relevant control of the LED control chip, such as overvoltage protection, the power supply voltage at the power supply end needs to be measured. However, the measurement of the power supply voltage is usually affected by the working state of the LED driver chip, resulting in inaccurate measurement results, thereby affecting the relevant control operations of the LED control chip, and even causing safety hazards to the LED control chip.
因此,需要能夠更準確地測量供電端的供電電壓的方式。 Therefore, a method is needed to more accurately measure the power supply voltage at the power supply end.
根據本發明的示例性實施例,提供了一種用於LED控制晶片的測量供電端的供電電壓的電路,所述供電端用於經由所述LED控制晶片的高壓引腳向連接到所述LED控制晶片的電源引腳的儲能器件供電,以使得所述儲能器件經由所述電源引腳向所述LED控制晶片提供工作電流,其中,所述電路包括:第一控制單元,被配置為連接在所述高壓引腳與所述電源引腳之間,用於根據第一控制信號接通或斷開所述高壓引腳與所述電源引腳之間的連接;以及電壓測量單元,被配置為連接在所述高壓引腳與參考地之間,用於根據第二控制信號開啟或停止經由所述高壓引腳對所 述供電電壓的測量,其中,在所述第一控制單元接通所述高壓引腳與所述電源引腳之間的連接的情況下,所述電壓測量單元停止經由所述高壓引腳對所述供電電壓的測量;在所述第一控制單元斷開所述高壓引腳與所述電源引腳之間的連接的情況下,所述電壓測量單元開啟經由所述高壓引腳對所述供電電壓的測量。 According to an exemplary embodiment of the present invention, a circuit for measuring a power supply voltage of a power supply terminal of an LED control chip is provided, wherein the power supply terminal is used to supply power to an energy storage device connected to a power supply pin of the LED control chip via a high voltage pin of the LED control chip, so that the energy storage device provides a working current to the LED control chip via the power supply pin, wherein the circuit comprises: a first control unit, configured to be connected between the high voltage pin and the power supply pin, and used to connect or disconnect the high voltage pin and the power supply pin according to a first control signal; connection; and a voltage measuring unit, configured to be connected between the high voltage pin and the reference ground, for starting or stopping the measurement of the power supply voltage via the high voltage pin according to a second control signal, wherein, when the first control unit connects the connection between the high voltage pin and the power supply pin, the voltage measuring unit stops the measurement of the power supply voltage via the high voltage pin; when the first control unit disconnects the connection between the high voltage pin and the power supply pin, the voltage measuring unit starts the measurement of the power supply voltage via the high voltage pin.
根據本發明的示例性實施例的用於LED控制晶片的測量供電端的供電電壓的電路,能夠通過在LED控制晶片的高壓引腳連接到電源引腳從而供電端向連接到電源引腳的儲能器件供電期間,停止對供電端的供電電壓的測量,並在LED控制晶片的高壓引腳與電源引腳的連接斷開從而供電端不向連接到電源引腳的儲能器件供電期間,對供電端的供電電壓進行測量,來防止LED控制晶片的工作狀態對供電電壓測量的影響,從而能夠提高測量供電電壓的準確度。 According to the circuit for measuring the power supply voltage of the power supply end of the LED control chip according to the exemplary embodiment of the present invention, the power supply voltage of the power supply end can be stopped from being measured when the high voltage pin of the LED control chip is connected to the power pin so that the power supply end supplies power to the energy storage device connected to the power pin, and the power supply voltage of the power supply end is measured when the high voltage pin of the LED control chip is disconnected from the power pin so that the power supply end does not supply power to the energy storage device connected to the power pin, so as to prevent the working state of the LED control chip from affecting the power supply voltage measurement, thereby improving the accuracy of measuring the power supply voltage.
100,200:LED控制晶片 100,200:LED control chip
1000:LED驅動電路 1000:LED driver circuit
110,210:電路 110,210: Circuit
120:恆流控制模組 120: Constant flow control module
211:第一控制單元 211: First control unit
212:電壓測量單元 212: Voltage measurement unit
213:限流單元 213: Current limiting unit
214:第二控制單元 214: Second control unit
215:信號生成單元 215:Signal generation unit
A:第一控制信號 A: First control signal
B:第二控制信號 B: Second control signal
C:電容值 C: Capacitance value
C1:第一電容器 C1: First capacitor
C2:存儲單元(第二電容器) C2: Storage unit (second capacitor)
Cvdd:儲能器件 Cvdd: energy storage device
D:汲極 D: Drain
D1:二極體 D1: diode
G:閘極 G: Gate
GATE:閘極引腳 GATE: Gate pin
HV:高壓引腳 HV: High Voltage Pin
I,Ihv:電流 I,Ihv: current
I1:工作電流 I1: Working current
L1:電感器 L1: Inductor
M1,M2:開關 M1,M2: switch
N1:第一節點 N1: First node
Nin:端子 Nin: Terminal
Nin1:輸入端子 Nin1: Input terminal
Nout1:第一輸出端子 Nout1: first output terminal
Nout2:第二輸出端子 Nout2: Second output terminal
R1:第一電阻器 R1: First resistor
R2:第一分壓單元 R2: The first voltage divider unit
R3:第二分壓單元 R3: The second voltage divider unit
Rp:電阻器 Rp: Resistor
S:源極 S: Source
s1:第一開關 s1: First switch
s2:第二開關 s2: Second switch
t,t1,T1,T2,T3:時間 t,t1,T1,T2,T3: time
V1:供電電壓 V1: Power supply voltage
V2:電壓 V2: voltage
Vbus:外部供電線路 Vbus: external power supply line
Vc:測量端子 Vc: measuring terminal
vc1,vc2:分壓 vc1,vc2: voltage divider
VDD:電源引腳 VDD: power pin
Vin:供電端 Vin: power supply end
從下面結合圖式對本發明的具體實施方式的描述中可以更好地理解本發明,其中:圖1示出了根據一個示例性實施例的具有LED驅動晶片的LED驅動電路的示意性電路圖。 The present invention can be better understood from the following description of the specific implementation of the present invention in conjunction with the drawings, wherein: FIG1 shows a schematic circuit diagram of an LED driver circuit with an LED driver chip according to an exemplary embodiment.
圖2示出了根據一個示例性實施例的圖1的電路中的電壓信號和電流信號的波形圖。 FIG2 shows a waveform diagram of a voltage signal and a current signal in the circuit of FIG1 according to an exemplary embodiment.
圖3示出了根據本發明的一個示例性實施例的用於LED控制晶片的測量供電端的供電電壓的電路的示意性框圖。 FIG3 shows a schematic block diagram of a circuit for measuring the power supply voltage at the power supply end of an LED control chip according to an exemplary embodiment of the present invention.
圖4示出了根據本發明的一個示例性實施例的用於LED控制晶片的測量供電端的供電電壓的電路的示意性電路圖。 FIG4 shows a schematic circuit diagram of a circuit for measuring the power supply voltage of a power supply terminal of an LED control chip according to an exemplary embodiment of the present invention.
圖5示出了根據本發明的一個示例性實施例的圖4的電路中的電壓信號和電流信號的波形圖。 FIG5 shows a waveform diagram of a voltage signal and a current signal in the circuit of FIG4 according to an exemplary embodiment of the present invention.
下面將詳細描述本發明的各個方面的特徵和示例性實施例。 在下面的詳細描述中,提出了許多具體細節,以便提供對本發明的全面理解。但是,對於本領域技術人員來說很明顯的是,本發明可以在不需要這些具體細節中的一些細節的情況下實施。下面對實施例的描述僅僅是為了通過示出本發明的示例來提供對本發明的更好的理解。本發明決不限於下面所提出的任何具體配置和演算法,而是在不脫離本發明的精神的前提下覆蓋了元素、部件和演算法的任何修改、替換和改進。在圖式和下面的描述中,沒有示出公知的結構和技術,以便避免對本發明造成不必要的模糊。 The features and exemplary embodiments of various aspects of the present invention are described in detail below. In the detailed description below, many specific details are set forth in order to provide a comprehensive understanding of the present invention. However, it is obvious to a person skilled in the art that the present invention can be implemented without some of these specific details. The following description of the embodiments is only for the purpose of providing a better understanding of the present invention by illustrating examples of the present invention. The present invention is in no way limited to any specific configuration and algorithm set forth below, but covers any modification, substitution and improvement of elements, components and algorithms without departing from the spirit of the present invention. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessary ambiguity of the present invention.
圖1示出了根據一個示例性實施例的具有LED控制晶片100的LED驅動電路1000的示意性電路圖。
FIG1 shows a schematic circuit diagram of an
如圖1所示,LED驅動電路1000經由輸入端子Nin1連接到外部供電線路Vbus,並經由第一輸出端子Nout1和第二輸出端子Nout2連接到LED,以使用外部供電線路Vbus的電力為LED供電。外部供電線路Vbus提供的電力可以是經過整流後的市電等。
As shown in FIG1 , the
LED驅動電路1000具有LED控制晶片100,並可利用LED控制晶片100將外部供電線路Vbus的電流轉換為用於為LED供電的恆定電流。例如,LED控制晶片100的恆流控制模組120可經由閘極引腳GATE連接到恆流開關M2的閘極G,並用於向恆流開關M2的閘極G提供控制信號,以通過控制恆流開關M2的接通或斷開來產生用於向LED供電的恆定電流。
The
為了使LED控制晶片100獲得工作所需的電力,LED控制晶片100的高壓引腳HV可連接到外部供電線路Vbus,以通過外部供電線路Vbus向連接到LED控制晶片100的電源引腳VDD的儲能器件(例如,儲能器件Cvdd)供電,以使得儲能器件Cvdd經由電源引腳VDD向LED控制晶片100提供工作電流。例如,如圖1所示,在LED控制晶片100中,高壓引腳HV可通過開關M1連接到電源引腳VDD,電源引腳VDD連接到作為儲能器件的儲能器件Cvdd。
In order for the
為了向LED控制晶片100提供靜電釋放(Electrostatic
Discharge,ESD)保護,並防止從LED控制晶片100向外部供電線路Vbus的電流倒流,可在外部供電線路Vbus與高壓引腳HV之間設置電阻器Rp。例如,在外部供電線路Vbus的供電電壓為高壓、例如平均電壓大於300V時,電阻器Rp可具有1-20K歐姆的阻值。此時,開關M1可以是高壓器件,例如,具有大於500V的工作電壓的高壓器件。
In order to provide electrostatic discharge (ESD) protection to the
由於需要對LED晶片進行諸如過壓保護等的相關控制,因此需要對外部供電線路Vbus的供電電壓進行測量。例如,如圖1所示,可通過串聯連接在高壓引腳HV與參考地之間的第一分壓單元R2和第二分壓單元R3對高壓引腳HV處的電壓進行分壓的方式,來經由測量端子Vc測量高壓引腳HV處的電壓的分壓,從而測量外部供電線路Vbus的供電電壓。 Since the LED chip needs to be controlled for overvoltage protection, the power supply voltage of the external power supply line Vbus needs to be measured. For example, as shown in Figure 1, the voltage at the high voltage pin HV can be divided by the first voltage divider R2 and the second voltage divider R3 connected in series between the high voltage pin HV and the reference ground, and the voltage at the high voltage pin HV can be measured through the measurement terminal Vc, thereby measuring the power supply voltage of the external power supply line Vbus.
然而,在開關M1接通的情況下,外部供電線路Vbus向儲能器件Cvdd供電,電阻器Rp上流過的電流Ihv為LED控制晶片100的工作電流,因而電阻器Rp兩端會具有相應的電壓降。此外,LED控制晶片100的工作電流會由於LED控制晶片的不同操作或不同工作狀態而變化。例如,在LED控制晶片100控制開關M2接通的瞬間、控制開關M2處於接通狀態期間、控制開關M2斷開的瞬間以及控制開關M2處於斷開狀態期間,LED控制晶片100的工作電流互不相同。此外,在LED控制晶片100處於啟動狀態、正常工作狀態、保護狀態、以及快速回應狀態下時,LED控制晶片100的工作電流也互不相同。LED控制晶片100的不斷變化的工作電流會導致電阻器Rp上的電壓降不斷變化,從而導致經由測量端子Vc測量的供電電壓不準確,而這可能會導致LED控制晶片產生誤判斷進而引起誤操作,甚至對LED控制晶片造成安全隱患。
However, when the switch M1 is turned on, the external power supply line Vbus supplies power to the energy storage device Cvdd, and the current Ihv flowing through the resistor Rp is the operating current of the
圖2示出了根據一個示例性實施例的圖1的電路中的電壓信號和電流信號的波形圖。 FIG2 shows a waveform diagram of a voltage signal and a current signal in the circuit of FIG1 according to an exemplary embodiment.
如圖2所示,外部供電線路Vbus具有供電電壓V1,在時間t1之前(圖2的時間t1的左側),開關M1處於斷開狀態,外部供電線路Vbus未向儲能器件Cvdd供電。圖1中的第一分壓單元R2的阻值與第二分 壓單元R3的阻值之和可設置得遠遠大於電阻器Rp的阻值,因而在時間t1之前,流經電阻器Rp的電流Ihv可近似為0,電阻器Rp的電壓降可忽略,高壓引腳HV處的電壓可近似為外部供電線路Vbus的供電電壓V1。此時,在測量端子Vc處測量的分壓vc1可以為vc1=V1×R2/(R2+R3),應該理解,該等式中的R2和R3分別表示第一分壓單元R2和第二分壓單元R3的阻值。 As shown in FIG2 , the external power supply line Vbus has a power supply voltage V1. Before time t1 (to the left of time t1 in FIG2 ), the switch M1 is in an open state, and the external power supply line Vbus does not supply power to the energy storage device Cvdd. The sum of the resistance of the first voltage divider R2 and the resistance of the second voltage divider R3 in FIG1 can be set to be much larger than the resistance of the resistor Rp. Therefore, before time t1, the current Ihv flowing through the resistor Rp can be approximately 0, the voltage drop of the resistor Rp can be ignored, and the voltage at the high voltage pin HV can be approximately equal to the power supply voltage V1 of the external power supply line Vbus. At this time, the voltage divider vc1 measured at the measuring terminal Vc can be vc1=V1×R2/(R2+R3). It should be understood that R2 and R3 in this equation represent the resistance values of the first voltage divider unit R2 and the second voltage divider unit R3, respectively.
在時間t1之時以及之後(圖2的時間t1的右側),開關M1處於接通狀態,外部供電線路Vbus向儲能器件Cvdd供電,此時,流經電阻器Rp的電流Ihv為LED控制晶片100的工作電流I1。相應地,電阻器Rp上的電壓降導致高壓引腳HV處的電壓從供電電壓V1下降到電壓V2。在測量端子Vc處測量的分壓由vc1變為vc2=(V1-I1×Rp)×R2/(R2+R3)。因此,在外部供電線路Vbus向儲能器件Cvdd供電期間,在LED控制晶片100的工作電流I1不斷變化時,經由測量端子Vc測量的供電電壓隨之變化而非常不準確。
At and after time t1 (to the right of time t1 in FIG. 2 ), the switch M1 is in the on state, and the external power supply line Vbus supplies power to the energy storage device Cvdd. At this time, the current Ihv flowing through the resistor Rp is the operating current I1 of the
為了至少部分地克服上述缺陷,根據本發明的示例性實施例提供了一種用於LED控制晶片的測量供電端的供電電壓的電路。 In order to at least partially overcome the above-mentioned defects, a circuit for measuring the power supply voltage of the power supply terminal of an LED control chip is provided according to an exemplary embodiment of the present invention.
圖3示出了根據本發明的一個示例性實施例的用於LED控制晶片200的測量供電端的供電電壓的電路210的示意性框圖。
FIG3 shows a schematic block diagram of a
如圖3所示的供電端Vin用於經由LED控制晶片200的高壓引腳HV向連接到LED控制晶片200的電源引腳VDD的儲能器件供電,以使得儲能器件經由電源引腳VDD向LED控制晶片200提供工作電流。 As shown in FIG3 , the power supply terminal Vin is used to supply power to the energy storage device connected to the power pin VDD of the LED control chip 200 via the high voltage pin HV of the LED control chip 200, so that the energy storage device provides the working current to the LED control chip 200 via the power pin VDD.
在一個實施例中,儲能器件Cvdd可以為第一電容器C1(例如,圖1所示的儲能器件Cvdd),第一電容器C1連接在電源引腳VDD與參考地之間。 In one embodiment, the energy storage device Cvdd can be a first capacitor C1 (for example, the energy storage device Cvdd shown in FIG. 1 ), and the first capacitor C1 is connected between the power pin VDD and the reference ground.
在一個實施例中,LED控制晶片200可用於LED驅動電路,LED驅動電路用於將外部供電線路的電流轉換為恆定電流以為LED供電。例如,LED驅動電路可以為圖1所示的驅動電路,外部供電線路可以為圖 1所示的外部供電線路Vbus。 In one embodiment, the LED control chip 200 can be used in an LED driving circuit, and the LED driving circuit is used to convert the current of the external power supply circuit into a constant current to power the LED. For example, the LED driving circuit can be the driving circuit shown in FIG. 1, and the external power supply circuit can be the external power supply circuit Vbus shown in FIG. 1.
在一個實施例中,供電端Vin可以為外部供電線路Vbus的用於連接到LED控制晶片200的端子(例如,圖1所示的輸入端子Nin1),或者供電端Vin可以為LED驅動電路的能夠向LED控制晶片200提供供電電壓的預定端子。供電電壓的平均電壓值可以大於第二電壓值。 In one embodiment, the power supply terminal Vin may be a terminal of the external power supply line Vbus for connecting to the LED control chip 200 (for example, the input terminal Nin1 shown in FIG. 1 ), or the power supply terminal Vin may be a predetermined terminal of the LED driving circuit capable of providing a power supply voltage to the LED control chip 200. The average voltage value of the power supply voltage may be greater than the second voltage value.
例如,在供電端Vin為外部供電線路Vbus的輸入端子Nin1的情況下,供電電壓可以為整流後的市電,該供電電壓的平均電壓值可大於300V。 For example, when the power supply terminal Vin is the input terminal Nin1 of the external power supply line Vbus, the power supply voltage can be the rectified mains power, and the average voltage value of the power supply voltage can be greater than 300V.
在供電端Vin為LED驅動電路的能夠向LED控制晶片200提供供電電壓的預定端子的情況下,在一個實施例中,該預定端子可以為LED控制晶片200的恆流開關(例如,圖1所示的開關M2)的汲極D。與圖1所示相似地,恆流開關M2的閘極G可連接到LED控制晶片200的恆流控制模組120,恆流開關M2的汲極D可經由二極體D1連接到LED驅動電路的第一輸出端子Nout1,並經由電感器L1連接到LED驅動電路的第二輸出端子Nout2,恆流開關M2的源極S可連接到參考地。外部供電線路Vbus可連接到第一輸出端子Nout1,第一輸出端子Nout1和第二輸出端子Nout2可用於連接LED。在這種情況下,例如,供電電壓的平均電壓值可大於500V。
In the case where the power supply terminal Vin is a predetermined terminal of the LED driving circuit capable of providing a power supply voltage to the LED control chip 200, in one embodiment, the predetermined terminal may be a drain D of a constant current switch (e.g., the switch M2 shown in FIG. 1 ) of the LED control chip 200. Similar to FIG. 1 , a gate G of the constant current switch M2 may be connected to the constant
換言之,圖3所示的電路210可用於替代圖1所示的電路110,並且圖3所示的LED控制晶片200的其它部分可以與圖1所示的LED控制晶片100的其它部分相同。或者,圖3所示的電路210可適用於圖1所示的LED驅動電路的變形電路,例如,圖3所示的電路210的供電端Vin可不連接到圖1所示的外部供電線路Vbus,而是如上所述地連接到圖1所示的開關M2的汲極D,以在開關M2斷開的情況下,通過開關M2的汲極處的電壓為第一電容器C1(儲能器件Cvdd)供電,並在開關M2斷開的情況下使用根據本發明的示例性實施例的電路210。應該理解,圖1和圖3所示的LED控制晶片還可包括未示出的其他模組。
In other words, the
參照圖3,根據本發明的示例性實施例的用於LED控制晶片200的測量供電端的供電電壓的電路210可包括:第一控制單元211和電壓測量單元212。
Referring to FIG. 3 , the
第一控制單元211可被配置為連接在高壓引腳HV與電源引腳VDD之間,用於根據第一控制信號(例如,圖4所示的信號A)接通或斷開高壓引腳HV與電源引腳VDD之間的連接。
The
電壓測量單元212可被配置為連接在高壓引腳HV與參考地之間,用於根據第二控制信號(例如,圖4所示的信號B)開啟或停止經由高壓引腳HV對供電電壓的測量。
The
在一個實施例中,在第一控制單元211接通高壓引腳HV與電源引腳VDD之間的連接的情況下,電壓測量單元212停止經由高壓引腳HV對供電電壓的測量;在第一控制單元211斷開高壓引腳HV與電源引腳VDD之間的連接的情況下,電壓測量單元212開啟經由高壓引腳HV對供電電壓的測量。
In one embodiment, when the
根據本發明的示例性實施例的用於LED控制晶片的測量供電端的供電電壓的電路,能夠通過在LED控制晶片的高壓引腳連接到電源引腳從而供電端向連接到電源引腳的儲能器件供電期間,停止對供電端的供電電壓的測量,並在LED控制晶片的高壓引腳與電源引腳的連接斷開從而供電端不向連接到電源引腳的儲能器件供電期間,對供電端的供電電壓進行測量,來防止LED控制晶片的工作狀態對供電電壓測量的影響,從而能夠提高測量供電電壓的準確度。 According to the circuit for measuring the power supply voltage of the power supply end of the LED control chip according to the exemplary embodiment of the present invention, the power supply voltage of the power supply end can be stopped from being measured when the high voltage pin of the LED control chip is connected to the power pin so that the power supply end supplies power to the energy storage device connected to the power pin, and the power supply voltage of the power supply end is measured when the high voltage pin of the LED control chip is disconnected from the power pin so that the power supply end does not supply power to the energy storage device connected to the power pin, so as to prevent the working state of the LED control chip from affecting the power supply voltage measurement, thereby improving the accuracy of measuring the power supply voltage.
以下參照圖4詳細描述電路210的一個示例性實施例。
An exemplary embodiment of the
圖4示出了根據本發明的一個示例性實施例的用於LED控制晶片200的測量供電端的供電電壓的電路210的示意性電路圖。
FIG4 shows a schematic circuit diagram of a
在以上的實施例中,LED控制晶片所用於的LED驅動電路可以具有大於預定值的功率因數(例如,大於0.9或其他值)。供電電壓可以為隨時間變化的電壓,例如,具有類似於正弦波的波形的電壓(例如, 整流後的市電)。 In the above embodiments, the LED driving circuit used by the LED control chip can have a power factor greater than a predetermined value (for example, greater than 0.9 or other values). The supply voltage can be a voltage that varies with time, for example, a voltage with a waveform similar to a sine wave (for example, rectified mains electricity).
在這種情況下,如圖4所示,電路210還可包括:限流單元213,限流單元213可被配置為連接在供電端Vin與高壓引腳HV之間,用於通過限制供電端Vin與高壓引腳HV之間的電流大小,來對LED控制晶片200提供靜電釋放(ESD)保護,並限制在供電電壓變化的過程中(例如,在供電電壓為0時)從LED控制晶片200向供電端Vin的電流倒流。在一個實施例中,限流單元213可以為具有第一阻值的第一電阻器R1,例如,圖1中的電阻器Rp。
In this case, as shown in FIG. 4 , the
如圖4所示,在一個實施例中,電壓測量單元212可包括:分壓單元和測量單元。
As shown in FIG. 4 , in one embodiment, the
分壓單元可被配置為連接在高壓引腳HV與參考地之間,用於對高壓引腳HV處的電壓進行分壓。測量單元可被配置為連接到該分壓單元,用於根據第二控制信號B開啟或停止經由測量高壓引腳HV處的電壓的分壓而對供電電壓的測量。 The voltage divider unit can be configured to be connected between the high voltage pin HV and the reference ground to divide the voltage at the high voltage pin HV. The measuring unit can be configured to be connected to the voltage divider unit to start or stop measuring the power supply voltage by measuring the voltage division at the high voltage pin HV according to the second control signal B.
在一個實施例中,分壓單元可包括:第一分壓單元R2和第二分壓單元R3。 In one embodiment, the voltage dividing unit may include: a first voltage dividing unit R2 and a second voltage dividing unit R3.
第一分壓單元R2可被配置為連接在高壓引腳HV與第一節點N1之間。在一個實施例中,第一分壓單元可以為具有第二阻值的第一分壓單元R2,該第一分壓單元R2可與圖1中的第一分壓單元R2相同。 The first voltage dividing unit R2 may be configured to be connected between the high voltage pin HV and the first node N1. In one embodiment, the first voltage dividing unit may be a first voltage dividing unit R2 having a second resistance value, and the first voltage dividing unit R2 may be the same as the first voltage dividing unit R2 in FIG. 1 .
第二分壓單元R3可被配置為連接在第一節點N1與參考地之間,第一節點N1處的電壓為高壓引腳HV處的電壓的分壓。在一個實施例中,第二分壓單元R3可以為具有第三阻值的第二分壓單元R3,該第二分壓單元R3可與圖1中的第二分壓單元R3相同。在一個實施例中,以上第二阻值與第三阻值之和可比第一阻值大至少第二數量級,即(R2+R3)>>R1,該不等式中的R1、R2和R3分別表示第一阻值、第二阻值和第三阻值。 The second voltage divider R3 can be configured to be connected between the first node N1 and the reference ground, and the voltage at the first node N1 is a voltage divided by the voltage at the high voltage pin HV. In one embodiment, the second voltage divider R3 can be a second voltage divider R3 with a third resistance value, and the second voltage divider R3 can be the same as the second voltage divider R3 in Figure 1. In one embodiment, the sum of the above second resistance value and the third resistance value can be at least a second order of magnitude greater than the first resistance value, that is, (R2+R3)>>R1, and R1, R2 and R3 in the inequality represent the first resistance value, the second resistance value and the third resistance value, respectively.
在工作電流為隨時間變化的電流的情況下,在第一控制單元
211接通高壓引腳HV與電源引腳VDD之間的連接時,限流單元213(第一電阻器R1(Rp))可具有(流過)工作電流,測量單元可停止對供電電壓的測量。在第一控制單元211斷開高壓引腳HV與電源引腳VDD之間的連接時,限流單元213可具有(流過)比工作電流小至少第一數量級的電流(即,遠小於工作電流的近似為0的電流),測量單元可開啟對供電電壓的測量。
In the case where the working current is a current that varies with time, when the
通過以上設置,可僅在供電端Vin不向第一電容器C1供電時,即流過第一電阻器R1的電流很小、從而可忽略第一電阻器R1的電壓降時,才開啟對供電電壓的測量,從而使得該測量不會受到LED控制晶片的工作電流的變化的影響,使得測量更準確。 Through the above settings, the measurement of the supply voltage can be turned on only when the power supply terminal Vin does not supply power to the first capacitor C1, that is, when the current flowing through the first resistor R1 is very small and the voltage drop of the first resistor R1 can be ignored, so that the measurement will not be affected by the change of the working current of the LED control chip, making the measurement more accurate.
在一個實施例中,測量單元可包括:第一開關s1和存儲單元C2。 In one embodiment, the measuring unit may include: a first switch s1 and a storage unit C2.
第一開關s1可被配置為連接在第一節點N1與測量端子Vc之間,用於根據第二控制信號B接通或斷開,以在第一開關s1接通的情況下經由測量端子Vc來測量高壓引腳HV處的電壓的分壓。由於(R2+R3)>>R1,因此該分壓可被視為與供電電壓對應。 The first switch s1 can be configured to be connected between the first node N1 and the measuring terminal Vc, and is used to be turned on or off according to the second control signal B, so as to measure the voltage division of the voltage at the high voltage pin HV through the measuring terminal Vc when the first switch s1 is turned on. Since (R2+R3)>>R1, the voltage division can be regarded as corresponding to the power supply voltage.
存儲單元C2可被配置為連接在測量端子Vc與參考地之間,用於在第一開關s1接通的情況下,存儲經由測量端子Vc測量的分壓,並在第一開關s1斷開的情況下,使測量端子處保持有測量的分壓。在一個實施例中,存儲單元C2可以為第二電容器。 The storage unit C2 can be configured to be connected between the measurement terminal Vc and the reference ground, and is used to store the divided voltage measured by the measurement terminal Vc when the first switch s1 is turned on, and to keep the measured divided voltage at the measurement terminal when the first switch s1 is turned off. In one embodiment, the storage unit C2 can be a second capacitor.
由此,可在測量單元停止對供電電壓進行測量時,也能夠在測量端子Vc處讀取/檢測到供電電壓。從而便於LED晶片對供電電壓的隨時讀取以及相關控制。 Therefore, when the measuring unit stops measuring the supply voltage, the supply voltage can still be read/detected at the measuring terminal Vc. This facilitates the LED chip to read the supply voltage at any time and related control.
如圖4所示,在一個實施例中,第一控制單元211可以為第二開關s2,第二開關s2可根據第一控制信號A接通或斷開。
As shown in FIG. 4 , in one embodiment, the
此外,為了提高電路210設置的便捷性,電路210還可保留有圖1所示的相應元件,例如,在一個實施例中,電路210還可包括:第
二控制單元214,第二控制單元214可被配置為連接在高壓引腳HV與第一控制單元211之間,用於根據供電信號(未示出)開啟或停止供電端Vin經由高壓引腳HV向第一電容器C1(Cvdd)的供電。例如,第二控制單元214可以為圖1所示的開關M1。
In addition, in order to improve the convenience of setting up the
例如,在供電端Vin為外部供電線路Vbus的相應端子Nin的情況下,供電信號可根據LED控制晶片的啟動信號而開啟從供電端Vin向第一電容器C1的供電,並根據LED控制晶片的關閉信號而停止從供電端Vin向第一電容器C1的供電。在供電端Vin為恆流開關M1的汲極D的情況下,供電信號可根據開關M1的斷開信號而開啟從供電端Vin向第一電容器C1的供電,並根據開關M1的接通信號而停止從供電端Vin向第一電容器C1的供電。 For example, when the power supply terminal Vin is the corresponding terminal Nin of the external power supply line Vbus, the power supply signal can start the power supply from the power supply terminal Vin to the first capacitor C1 according to the start signal of the LED control chip, and stop the power supply from the power supply terminal Vin to the first capacitor C1 according to the shutdown signal of the LED control chip. When the power supply terminal Vin is the drain D of the constant current switch M1, the power supply signal can start the power supply from the power supply terminal Vin to the first capacitor C1 according to the disconnection signal of the switch M1, and stop the power supply from the power supply terminal Vin to the first capacitor C1 according to the connection signal of the switch M1.
相應地,第一控制單元211可被配置為連接在第二控制單元214與電源引腳VDD之間,用於在第二控制單元214開啟供電端Vin經由高壓引腳HV向第一電容器C1的供電的情況下,根據第一控制信號A接通或斷開高壓引腳HV與電源引腳VDD之間的連接。
Correspondingly, the
通過以上方式,可在不改變圖1所示的電路110的整體佈局的情況下方便地設置根據本發明的示例性實施例的電路210。
In the above manner, the
此外,為了生成以上第一控制信號A和第二控制信號B,在一個實施例中,根據本發明的示例性實施例的電路210還可包括:信號生成單元215,信號生成單元215可被配置為生成作為脈寬調變信號的第一控制信號A和第二控制信號B。
In addition, in order to generate the above first control signal A and second control signal B, in one embodiment, the
為了在通過第一控制信號A斷開供電端Vin向第一電容器C1的供電期間,使得第一電容器C1能夠正常地為LED控制晶片200提供相應的工作電力,第一電容器C1兩端的電壓需要保持為基本穩定的電壓,即,第一電容器C1的電壓變化不應太大。因此,在一個實施例中,第一控制信號A可具有預定占空比,該預定占空比可使得在第二開關s2根據第一控制信號A斷開期間,第一電容器C1兩端的電壓的變化量小於第一預 定值,例如小於預定百分比。例如,可通過等式△U×C=I×t來設置該占空比,在該等式中,△U可表示電壓變化,C可表示第一電容器C1的電容值,I可第一電容器C1提供的電流,t可表示時間、例如第二開關s2斷開的時間。 In order to enable the first capacitor C1 to normally provide corresponding working power to the LED control chip 200 during the period when the power supply terminal Vin is disconnected from the first control signal A, the voltage across the first capacitor C1 needs to be kept at a substantially stable voltage, that is, the voltage variation of the first capacitor C1 should not be too large. Therefore, in one embodiment, the first control signal A may have a predetermined duty cycle, which may make the variation of the voltage across the first capacitor C1 less than a first predetermined value, such as less than a predetermined percentage, during the period when the second switch s2 is disconnected according to the first control signal A. For example, the duty cycle may be set by the equation ΔU × C = I × t , where ΔU may represent voltage change, C may represent capacitance of the first capacitor C1, I may represent current provided by the first capacitor C1, and t may represent time, such as the time when the second switch s2 is turned off.
在一個實施例中,第一開關s1和第二開關s2可以為具有相同的接通位準的開關(例如,均為NMOS管或均為PMOS管),此時,第一控制信號A和第二控制信號B可以為反相的信號。 In one embodiment, the first switch s1 and the second switch s2 may be switches with the same on-state level (for example, both are NMOS tubes or both are PMOS tubes), and in this case, the first control signal A and the second control signal B may be inverted signals.
應該理解,第一開關s1和第二開關s2還可以為具有不同的接通位準的開關(例如,一個為NMOS管一個為PMOS管),此時,第一控制信號A和第二控制信號B可以為相同的信號。 It should be understood that the first switch s1 and the second switch s2 can also be switches with different on-state levels (for example, one is an NMOS tube and the other is a PMOS tube). In this case, the first control signal A and the second control signal B can be the same signal.
圖5示出了根據本發明的一個示例性實施例的圖4的電路中的電壓信號和電流信號的波形圖。 FIG5 shows a waveform diagram of a voltage signal and a current signal in the circuit of FIG4 according to an exemplary embodiment of the present invention.
圖5是第一開關s1和第二開關s2均為NMOS管、第一控制信號A和第二控制信號B為反相的信號的示例。 Figure 5 is an example where both the first switch s1 and the second switch s2 are NMOS tubes, and the first control signal A and the second control signal B are inverted signals.
如圖5所示,在時間T1之前(圖5的時間T1的左側),開關M1處於斷開狀態,供電端Vin未向第一電容器C1供電,流經電阻器Rp的電流Ihv可近似為0,高壓引腳HV處的電壓可近似為供電端Vin的供電電壓V1。第一控制信號A可具有低位準(也可以具有高位準),第二控制信號B可具有高位準,第一開關s1接通,第二開關s2斷開(也可以接通),此時,在測量端子Vc處測量的分壓vc1可以為vc1=V1×R2/(R2+R3),這與圖2相同。 As shown in FIG5 , before time T1 (to the left of time T1 in FIG5 ), switch M1 is in the disconnected state, the power supply terminal Vin does not supply power to the first capacitor C1, the current Ihv flowing through the resistor Rp can be approximately 0, and the voltage at the high voltage pin HV can be approximately equal to the power supply voltage V1 of the power supply terminal Vin. The first control signal A can have a low level (or a high level), the second control signal B can have a high level, the first switch s1 is turned on, and the second switch s2 is turned off (or turned on). At this time, the voltage division vc1 measured at the measurement terminal Vc can be vc1=V1×R2/(R2+R3), which is the same as FIG2 .
在時間T1之時以及之後,開關M1處於接通狀態。 At and after time T1, switch M1 is in the on state.
在時間T1至時間T2期間,第一控制信號A可具有高位準,第二控制信號B可具有低位準,第一開關s1可斷開,第二開關s2可接通,流經第一電阻器R1(Rp)的電流Ihv為LED控制晶片的工作電流I1。相應地,電阻器Rp上的電壓降導致高壓引腳HV處的電壓從供電電壓V1下降到電壓V2。此時,測量端子Vc處由於存儲單元C2(第二電容器)而保持 有之前測量的分壓vc1。 During the period from time T1 to time T2, the first control signal A may have a high level, the second control signal B may have a low level, the first switch s1 may be disconnected, the second switch s2 may be connected, and the current Ihv flowing through the first resistor R1 (Rp) is the operating current I1 of the LED control chip. Correspondingly, the voltage drop on the resistor Rp causes the voltage at the high voltage pin HV to drop from the supply voltage V1 to the voltage V2. At this time, the measurement terminal Vc maintains the previously measured divided voltage vc1 due to the storage unit C2 (second capacitor).
在時間T2至時間T3期間,第一控制信號A可具有低位準,第二控制信號B可具有高位準,第一開關s1可接通,第二開關s2可斷開,供電端Vin未向第一電容器C1供電,流經電阻器Rp的電流Ihv可近似為0,高壓引腳HV處的電壓可近似為供電端Vin的供電電壓V1。此時,在測量端子Vc處測量的分壓vc1可以為vc1=V1×R2/(R2+R3)。 During the period from time T2 to time T3, the first control signal A may have a low level, the second control signal B may have a high level, the first switch s1 may be turned on, the second switch s2 may be turned off, the power supply terminal Vin does not supply power to the first capacitor C1, the current Ihv flowing through the resistor Rp may be approximately 0, and the voltage at the high voltage pin HV may be approximately the power supply voltage V1 of the power supply terminal Vin. At this time, the divided voltage vc1 measured at the measurement terminal Vc may be vc1=V1×R2/(R2+R3).
由此,可以保障測量端子Vc處測量的分壓vc1準確地與供電電壓對應,從而提高了對供電電壓進行測量的準確性。 Therefore, it can be ensured that the voltage division vc1 measured at the measurement terminal Vc accurately corresponds to the power supply voltage, thereby improving the accuracy of measuring the power supply voltage.
應該理解,圖5(以及圖2)僅是示意性的波形圖,在供電電壓為隨時間變化的電壓(例如,具有類似於正弦波的波形)的情況下,圖5僅示出很短的時間段,因此近似地將供電電壓示出為了恆定電壓,但供電電壓可具有與圖5所示不同的任意波形。 It should be understood that FIG. 5 (and FIG. 2) are only schematic waveform diagrams. When the supply voltage is a voltage that varies with time (for example, having a waveform similar to a sine wave), FIG. 5 only shows a short period of time, and thus approximately shows the supply voltage as a constant voltage. However, the supply voltage may have any waveform different from that shown in FIG. 5.
應該理解,以上示出的各種數值僅是示例,可根據實際需要而將這些值設置為任意不同的值。 It should be understood that the various numerical values shown above are only examples, and these values can be set to any different values according to actual needs.
以上所述的結構框圖中所示的功能塊可以實現為硬體、軟體、韌體或者它們的組合。當以硬體方式實現時,其可以例如是電子電路、特殊應用積體電路(Application Specific Integrated Circuit,ASIC)、適當的韌體、外掛程式、功能卡等。當以軟體方式實現時,本發明的元素是被用於執行所需任務的程式或者程式碼片段。程式或者程式碼片段可以存儲在機器可讀介質中,或者通過載波中攜帶的資料信號在傳輸介質或者通信鏈路上傳送。“機器可讀介質”可以包括能夠存儲或傳輸資訊的任何介質。機器可讀介質的示例包括電子電路、半導體記憶體設備、唯讀記憶體(Read Only Memory,ROM)、快閃記憶體、可擦除ROM(Erasable Read Only Memory,EROM)、磁片、光碟唯讀記憶體(Compact Disc Read-Only Memory,CD-ROM)、光碟、硬碟、光纖介質、射頻(Radio Frequency,RF)鏈路等。程式碼片段可以經由諸如網際網路、內聯網等的電腦網路被下載。 The functional blocks shown in the structural block diagram described above can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or program code snippets used to perform the required tasks. The programs or program code snippets can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link via a data signal carried in a carrier. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, read-only memory (ROM), flash memory, erasable ROM (EROM), disks, compact disc read-only memory (CD-ROM), optical discs, hard disks, optical fiber media, radio frequency (RF) links, etc. The code snippet can be downloaded via a computer network such as the Internet, an intranet, etc.
本發明可以以其他的具體形式實現,而不脫離其精神和本質 特徵。例如,特定實施例中所描述的演算法可以被修改,而系統體系結構並不脫離本發明的基本精神。因此,當前的實施例在所有方面都被看作是示例性的而非限定性的,本發明的範圍由所附請求項而非上述描述定義,並且,落入請求項的含義和等同物的範圍內的全部改變從而都被包括在本發明的範圍之中。 The present invention can be implemented in other specific forms without departing from its spirit and essential features. For example, the algorithm described in a specific embodiment can be modified, and the system architecture does not deviate from the basic spirit of the present invention. Therefore, the current embodiment is regarded as illustrative rather than restrictive in all aspects, the scope of the present invention is defined by the attached claims rather than the above description, and all changes that fall within the meaning and equivalent scope of the claims are included in the scope of the present invention.
200:LED控制晶片 200:LED control chip
210:電路 210: Circuit
211:第一控制單元 211: First control unit
212:電壓測量單元 212: Voltage measurement unit
C1:第一電容器 C1: First capacitor
Cvdd:儲能器件 Cvdd: energy storage device
GATE:閘極引腳 GATE: Gate pin
HV:高壓引腳 HV: High Voltage Pin
VDD:電源引腳 VDD: power pin
Vin:供電端 Vin: power supply end
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CN202211718523.0 | 2022-12-29 |
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TWI847604B true TWI847604B (en) | 2024-07-01 |
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US20210274610A1 (en) | 2020-03-02 | 2021-09-02 | Rohm Co., Ltd. | Driving device |
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US20210274610A1 (en) | 2020-03-02 | 2021-09-02 | Rohm Co., Ltd. | Driving device |
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