TW201545448A - Over-current protecting circuit and method for providing over-current protecting reference signal - Google Patents
Over-current protecting circuit and method for providing over-current protecting reference signal Download PDFInfo
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Abstract
Description
本發明是有關於一種電源轉換裝置的過電流保護技術,且特別是有關於一種過電流保護電路以及提供過電流保護參考訊號的方法。 The present invention relates to an overcurrent protection technique for a power conversion device, and more particularly to an overcurrent protection circuit and a method of providing an overcurrent protection reference signal.
電源轉換裝置(power conversion apparatus)主要的用途乃是將電力公司所提供之高壓且低穩定性的交流電壓(AC voltage)轉換成適合各種電子裝置(electronic devices)所使用之低壓且穩定性較佳的直流電壓(DC voltage)。因此,電源轉換裝置廣泛地應用在電腦、辦公室自動化設備、工業控制設備,以及通訊設備等電子裝置中。 The main purpose of the power conversion apparatus is to convert the high voltage and low stability AC voltage provided by the power company into a low voltage suitable for various electronic devices and has better stability. DC voltage. Therefore, power conversion devices are widely used in electronic devices such as computers, office automation equipment, industrial control equipment, and communication equipment.
圖1為習知的電源轉換裝置的示意圖。電源轉換裝置10包括整流電路12、變壓器T、回授單元14、控制電路50以及功率開關Q。整流電路12接收交流電壓AC_IN並進行整流。反應在變壓器T之二次側NS的交流電壓(由變壓器T之一次側NP、二 次側NS的線圈比(turn ratio)n所決定)會經由二極體D1的整流以及電容C1的濾波後以轉換成輸出電壓Vout。回授單元14用以接收輸出電壓Vout,並據以輸出關聯於電子裝置40之負載狀態(loading status)的回授訊號Vfb。控制電路50根據回授訊號Vfb的工作週期(duty cycle)來產生過電流保護參考訊號Vlimit,並利用過電流保護參考訊號Vlimit來產生用於調整功率開關Q的脈寬調變訊號Vpwm。 1 is a schematic diagram of a conventional power conversion device. The power conversion device 10 includes a rectifier circuit 12, a transformer T, a feedback unit 14, a control circuit 50, and a power switch Q. The rectifier circuit 12 receives the AC voltage AC_IN and rectifies it. Reaction of the AC voltage on the secondary side NS of the transformer T (by the primary side of the transformer T NP, two The coil ratio of the secondary side NS is determined by the rectification of the diode D1 and the filtering of the capacitor C1 to be converted into the output voltage Vout. The feedback unit 14 is configured to receive the output voltage Vout and output a feedback signal Vfb associated with the loading status of the electronic device 40. The control circuit 50 generates an overcurrent protection reference signal Vlimit according to a duty cycle of the feedback signal Vfb, and generates a pulse width modulation signal Vpwm for adjusting the power switch Q by using the overcurrent protection reference signal Vlimit.
控制電路50在進行定功率控制時,其架構包括過電流保護電路20。過電流保護電路20根據回授訊號Vfb的工作週期(duty cycle,或稱作責任週期)來產生過電流保護參考訊號Vlimit。前述的工作週期決定了過電流保護參考訊號Vlimit的大小。由於前述的工作週期關聯於輸出電壓Vout,且輸出電壓Vout又與變壓器T的設計有關,亦即輸出電壓Vout與線圈比n有關。因此可理解為過電流保護參考訊號Vlimit與輸出電壓Vout(或電子裝置40之負載狀態)有關,且過電流保護參考訊號Vlimit也與線圈比n有關。一般來說,在某些極端操作下,因負載狀態的變化或是變壓器T的線圈比n過大,會造成過電流保護參考訊號Vlimit的數值非常不穩定。故習知電源轉換裝置10的過電流保護控制並不穩定。 When the control circuit 50 performs constant power control, its architecture includes an overcurrent protection circuit 20. The overcurrent protection circuit 20 generates an overcurrent protection reference signal Vlimit according to a duty cycle (referred to as a duty cycle) of the feedback signal Vfb. The aforementioned duty cycle determines the magnitude of the overcurrent protection reference signal Vlimit. Since the aforementioned duty cycle is associated with the output voltage Vout, and the output voltage Vout is again related to the design of the transformer T, that is, the output voltage Vout is related to the coil ratio n. Therefore, it can be understood that the overcurrent protection reference signal Vlimit is related to the output voltage Vout (or the load state of the electronic device 40), and the overcurrent protection reference signal Vlimit is also related to the coil ratio n. In general, under certain extreme operations, the value of the overcurrent protection reference signal Vlimit is very unstable due to a change in the load state or a coil ratio n of the transformer T. Therefore, the overcurrent protection control of the conventional power conversion device 10 is not stable.
有鑑於此,本發明提出一種過電流保護電路以及提供過電流保護參考訊號的方法,藉以解決先前技術所述及的問題。 In view of this, the present invention provides an overcurrent protection circuit and a method of providing an overcurrent protection reference signal to solve the problems described in the prior art.
本發明提供了一種過電流保護電路,其包括電阻網路、 波峰偵測單元以及第一數位至類比轉換器。電阻網路用以接收輸入電壓,並提供分壓電壓。波峰偵測單元耦接電阻網路。波峰偵測單元接收分壓電壓,對分壓電壓執行取樣及計數操作,據以產生數位波峰值。第一數位至類比轉換器耦接波峰偵測單元,對數位波峰值執行數位至類比轉換,據以提供過電流保護參考訊號。 The present invention provides an overcurrent protection circuit including a resistor network, The peak detection unit and the first digit to analog converter. The resistor network is used to receive the input voltage and provide a divided voltage. The peak detecting unit is coupled to the resistor network. The peak detecting unit receives the divided voltage, and performs sampling and counting operations on the divided voltage to generate a digital wave peak. The first digital to analog converter is coupled to the peak detecting unit, and performs digital to analog conversion on the digital wave peak to provide an overcurrent protection reference signal.
於本發明的一實施例中,輸入電壓為交流電壓經整流後的全波或半波訊號,或經電容濾波後的直流訊號。 In an embodiment of the invention, the input voltage is a full-wave or half-wave signal after rectification of the AC voltage, or a DC signal filtered by the capacitor.
於本發明的一實施例中,波峰偵測單元包括比較器、正反器、計數器、第二數位至類比轉換器以及暫存器。比較器的第一輸入端接收分壓電壓。正反器的資料輸入端耦接比較器的輸出。計數器的時脈輸入端耦接正反器的暫存資料輸出端。第二數位至類比轉換器的輸入端耦接計數器的輸出,用以提供波峰訊號給比較器的第二輸入端。暫存器的輸入端耦接計數器的輸出,其輸出端輸出數位波峰值。 In an embodiment of the invention, the peak detecting unit includes a comparator, a flip-flop, a counter, a second digit to analog converter, and a register. The first input of the comparator receives the divided voltage. The data input of the flip-flop is coupled to the output of the comparator. The clock input end of the counter is coupled to the temporary data output end of the flip flop. The input of the second digit to the analog converter is coupled to the output of the counter for providing a peak signal to the second input of the comparator. The input of the register is coupled to the output of the counter, and the output of the register outputs a peak of the digital wave.
於本發明的一實施例中,波峰偵測單元更週期性地更新數位波峰值,且在週期性地更新數位波峰值時,用來重置波峰偵測單元的週期大小大於輸入電壓的週期大小。 In an embodiment of the invention, the peak detecting unit periodically updates the digital wave peak, and when periodically updating the digital wave peak, the period for resetting the peak detecting unit is larger than the period of the input voltage. .
於本發明的一實施例中,過電流保護參考訊號與輸入電壓的波峰變化呈現反比。當輸入電壓的波峰變化由低值趨向高值時,過電流保護參考訊號的變化係從高值往低值下降。當輸入電壓的波峰變化由高值趨向低值時,過電流保護參考訊號的變化係從低值往高值上升。 In an embodiment of the invention, the overcurrent protection reference signal is inversely proportional to the peak change of the input voltage. When the peak change of the input voltage goes from a low value to a high value, the change of the overcurrent protection reference signal decreases from a high value to a low value. When the peak change of the input voltage goes from a high value to a low value, the change of the overcurrent protection reference signal rises from a low value to a high value.
本發明另提供了一種提供過電流保護參考訊號的方法,包括以下步驟。根據輸入電壓來提供分壓電壓;對分壓電壓執行 取樣及計數操作,據以產生數位波峰值;以及對數位波峰值執行數位至類比轉換,據以提供過電流保護參考訊號。 The present invention further provides a method of providing an overcurrent protection reference signal, comprising the following steps. Providing a divided voltage according to the input voltage; performing a divided voltage Sampling and counting operations to generate digital wave peaks; and digital-to-analog conversion of digital wave peaks to provide overcurrent protection reference signals.
於本發明的一示範性實施例中,其中對該分壓電壓執行該取樣及計數操作之步驟更包括:週期性地更新該數位波峰值。更新該數位波峰值的週期大小大於該交流電壓的週期大小。 In an exemplary embodiment of the invention, the step of performing the sampling and counting operations on the divided voltage further comprises periodically updating the digital peak. The period of updating the peak of the digital wave is greater than the period of the alternating voltage.
基於上述,在本發明中的過電流保護電路與提供過電流保護參考訊號的方法,係根據輸入電壓的波峰變化來提供過電流保護參考訊號。過電流保護參考訊號的產生方式與變壓器的線圈比無關,也與輸出電壓無關,從而得以解決先前技術所述及的問題。 Based on the above, the overcurrent protection circuit and the method for providing an overcurrent protection reference signal in the present invention provide an overcurrent protection reference signal according to a peak change of the input voltage. The overcurrent protection reference signal is generated independently of the coil ratio of the transformer and also independent of the output voltage, thereby solving the problems described in the prior art.
應瞭解的是,上述一般描述及以下具體實施方式僅為例示性及闡釋性的,其並不能限制本發明所欲主張之範圍。 It is to be understood that the foregoing general description and claims
10‧‧‧電源轉換裝置 10‧‧‧Power conversion device
12‧‧‧整流電路 12‧‧‧Rectifier circuit
14‧‧‧回授單元 14‧‧‧Responsible unit
20‧‧‧過電流保護電路 20‧‧‧Overcurrent protection circuit
40‧‧‧電子裝置 40‧‧‧Electronic devices
50‧‧‧控制電路 50‧‧‧Control circuit
110‧‧‧電源轉換裝置 110‧‧‧Power conversion device
120‧‧‧過電流保護電路 120‧‧‧Overcurrent protection circuit
122‧‧‧電阻網路 122‧‧‧Resistor network
124‧‧‧波峰偵測單元 124‧‧‧Crest detection unit
126‧‧‧數位至類比轉換器 126‧‧‧Digital to analog converter
128‧‧‧比較器 128‧‧‧ comparator
130‧‧‧正反器 130‧‧‧Factor
132‧‧‧計數器 132‧‧‧ counter
134‧‧‧數位至類比轉換器 134‧‧‧Digital to analog converter
136‧‧‧暫存器 136‧‧‧ register
140‧‧‧比較器 140‧‧‧ Comparator
142‧‧‧取樣脈波產生器 142‧‧‧Sampling pulse generator
144‧‧‧延遲單元 144‧‧‧Delay unit
146‧‧‧取樣脈波產生器 146‧‧‧Sampling pulse generator
148‧‧‧延遲單元 148‧‧‧Delay unit
150‧‧‧控制電路 150‧‧‧Control circuit
AC_IN‧‧‧交流電壓 AC_IN‧‧‧AC voltage
C1、C2‧‧‧電容 C1, C2‧‧‧ capacitor
D1‧‧‧二極體 D1‧‧‧ diode
Dp[0:n-1]‧‧‧數位波峰值 Dp[0:n-1]‧‧‧ digital wave peak
Fdp[0:n-1]‧‧‧計數值 Fdp[0:n-1]‧‧‧ count value
n‧‧‧線圈比 N‧‧‧ coil ratio
NP‧‧‧一次側 NP‧‧‧ primary side
NS‧‧‧二次側 NS‧‧‧ secondary side
OCP‧‧‧過電流保護訊號 OCP‧‧‧Overcurrent protection signal
RS‧‧‧感測電阻 RS‧‧‧ sense resistor
R1、R2‧‧‧電阻 R1, R2‧‧‧ resistance
S1、S2‧‧‧取樣脈波 S1, S2‧‧‧ sampling pulse wave
S10、S20、S30‧‧‧步驟 S10, S20, S30‧‧‧ steps
T‧‧‧變壓器 T‧‧‧Transformer
Tac、Tfast、Tupdate‧‧‧週期大小 Tac, Tfast, Tupdate‧‧‧ cycle size
Vcs‧‧‧感測電壓 Vcs‧‧‧ sense voltage
Vcs_limit‧‧‧過電流保護參考訊號 Vcs_limit‧‧‧Overcurrent protection reference signal
Vfb‧‧‧回授訊號 Vfb‧‧‧ feedback signal
Vin‧‧‧輸入電壓 Vin‧‧‧Input voltage
Vlimit‧‧‧過電流保護參考訊號 Vlimit‧‧‧Overcurrent protection reference signal
Vout‧‧‧輸出電壓 Vout‧‧‧ output voltage
Vpwm‧‧‧脈寬調變訊號 Vpwm‧‧‧ pulse width modulation signal
VB‧‧‧分壓電壓 VB‧‧ ‧ voltage divider
Vpeak‧‧‧波峰訊號 Vpeak‧‧‧Crest Signal
下面的所附圖式是本發明的說明書的一部分,其繪示了本發明的示例實施例,所附圖式係與說明書的描述一起用來說明本發明的原理。 The following drawings are a part of the specification of the invention, and are in the
圖1為習知的電源轉換裝置的示意圖。 1 is a schematic diagram of a conventional power conversion device.
圖2是根據本發明一實施例的電源轉換裝置的示意圖。 2 is a schematic diagram of a power conversion device in accordance with an embodiment of the present invention.
圖3是根據本發明一實施例的過電流保護電路的電路圖。 3 is a circuit diagram of an overcurrent protection circuit in accordance with an embodiment of the present invention.
圖4是根據本發明一實施例的波形示意圖。 4 is a schematic diagram of a waveform in accordance with an embodiment of the present invention.
圖5是根據本發明一實施例的過電流保護參考訊號與分壓電壓的波峰兩者之間的變化圖。 FIG. 5 is a graph showing changes between an overcurrent protection reference signal and a peak of a divided voltage according to an embodiment of the present invention.
圖6繪示本發明一實施例的過電流保護參考訊號的提供方法 的流程圖。 FIG. 6 illustrates a method for providing an overcurrent protection reference signal according to an embodiment of the present invention; Flow chart.
現在將詳細參考本發明的實施例,並在附圖中說明所述的實施例之實例。另外,在圖式及實施方式中所使用的相同或類似標號的元件/構件,係用來代表相同或類似部分。 Reference will now be made in detail to the embodiments of the embodiments embodiments In addition, the same or similar reference numerals and components used in the drawings and the embodiments are used to represent the same or similar parts.
圖2是根據本發明一實施例的電源轉換裝置的示意圖。請參閱圖2,電源轉換裝置110包括整流電路12、變壓器T、控制電路150、功率開關Q以及感測電阻RS。 2 is a schematic diagram of a power conversion device in accordance with an embodiment of the present invention. Referring to FIG. 2, the power conversion device 110 includes a rectifier circuit 12, a transformer T, a control circuit 150, a power switch Q, and a sense resistor RS.
整流電路12用以接收交流電壓(AC voltage)AC_IN,並對交流電壓AC_IN進行轉換後而提供輸入電壓(input voltage)Vin。亦即輸入電壓Vin為交流電壓AC_IN經整流後的訊號。輸入電壓Vin可以為全波或半波訊號。在另一實施例中,電源轉換裝置110可以不包括整流電路12,輸入電壓Vin可以直接接收類似於經電容C2濾波後的直流訊號。 The rectifier circuit 12 is configured to receive an AC voltage AC_IN and convert the AC voltage AC_IN to provide an input voltage Vin. That is, the input voltage Vin is a rectified signal of the AC voltage AC_IN. The input voltage Vin can be a full wave or a half wave signal. In another embodiment, the power conversion device 110 may not include the rectifier circuit 12, and the input voltage Vin may directly receive a DC signal similar to that filtered by the capacitor C2.
變壓器T具有一次側(primary side)NP以及二次側(secondary side)NS。變壓器T之一次側NP的第一端用以接收輸入電壓Vin。功率開關Q的第一端耦接變壓器T之一次側NP的第二端。功率開關Q的第二端可以透過感測電阻RS而耦接至一接地電位(ground potential)。功率開關Q的控制端用以接收控制電路50所提供的脈寬調變訊號(pulse width modulation signal)Vpwm。變壓器T之二次側NS用以反應於功率開關Q的切換而提供輸出電壓Vout給電子裝置(electronic device)40。 The transformer T has a primary side NP and a secondary side NS. The first end of the primary side NP of the transformer T is for receiving the input voltage Vin. The first end of the power switch Q is coupled to the second end of the primary side NP of the transformer T. The second end of the power switch Q can be coupled to a ground potential through the sensing resistor RS. The control terminal of the power switch Q is configured to receive a pulse width modulation signal Vpwm provided by the control circuit 50. The secondary side NS of the transformer T is used to provide an output voltage Vout to an electronic device 40 in response to switching of the power switch Q.
控制電路150可以包括過電流保護電路120與比較器 140。過電流保護電路120根據輸入電壓Vin來產生過電流保護參考訊號Vcs_limit,至於產生方式將於下文的圖3實施例進行詳細說明。 Control circuit 150 can include overcurrent protection circuit 120 and comparator 140. The overcurrent protection circuit 120 generates an overcurrent protection reference signal Vcs_limit according to the input voltage Vin, and the manner of generation will be described in detail in the embodiment of FIG. 3 below.
此外,在本實施例中,過電流保護參考訊號Vcs_limit的產生方式與變壓器T的線圈比(turn ratio)n無關,也與輸出電壓Vout無關。控制電路150在進行定功率控制時,比較器140可以比較過電流保護參考訊號Vcs_limit與感測電壓Vcs來提供過電流保護訊號OCP。 Further, in the present embodiment, the manner in which the overcurrent protection reference signal Vcs_limit is generated is independent of the turn ratio n of the transformer T, and is also independent of the output voltage Vout. When the control circuit 150 performs the constant power control, the comparator 140 can compare the overcurrent protection reference signal Vcs_limit with the sensing voltage Vcs to provide the overcurrent protection signal OCP.
圖3是根據本發明一實施例的過電流保護電路120的電路圖。請合併參閱圖2和圖3,過電流保護電路120包括電阻網路122、波峰偵測單元124以及數位至類比轉換器126。 FIG. 3 is a circuit diagram of an overcurrent protection circuit 120 in accordance with an embodiment of the present invention. Referring to FIG. 2 and FIG. 3 together, the overcurrent protection circuit 120 includes a resistor network 122, a peak detecting unit 124, and a digital to analog converter 126.
電阻網路122可以包括電阻R1和R2,用以接收輸入電壓Vin,並提供分壓電壓VB。電阻網路122亦可包括其他的阻抗元件,本實施例在此並不限制電阻網路122的實施態樣。 The resistor network 122 can include resistors R1 and R2 for receiving the input voltage Vin and providing a divided voltage VB. The resistor network 122 can also include other impedance components, and the embodiment does not limit the implementation of the resistor network 122 herein.
波峰偵測單元124耦接電阻網路122與數位至類比轉換器126。波峰偵測單元124接收分壓電壓VB,對分壓電壓VB執行取樣及計數操作,據以產生數位波峰值Dp[0:n-1]。接著,數位至類比轉換器126對數位波峰值Dp[0:n-1]執行數位至類比轉換,據以提供過電流保護參考訊號Vcs_limit。 The peak detecting unit 124 is coupled to the resistor network 122 and the digital to analog converter 126. The peak detecting unit 124 receives the divided voltage VB, and performs sampling and counting operations on the divided voltage VB, thereby generating a digital wave peak value Dp[0:n-1]. Next, the digital-to-analog converter 126 performs a digital-to-analog conversion on the digital peak value Dp[0:n-1] to provide an overcurrent protection reference signal Vcs_limit.
更清楚來說,波峰偵測單元124包括比較器128、正反器130、計數器132、數位至類比轉換器134以及暫存器136。比較器128的第一輸入端接收分壓電壓VB。正反器130的資料輸入端耦接比較器128的輸出。計數器132的時脈輸入端耦接正反器130的暫存資料輸出端。數位至類比轉換器134的輸入端耦接計數器 132的輸出。 More specifically, the peak detecting unit 124 includes a comparator 128, a flip-flop 130, a counter 132, a digital-to-analog converter 134, and a register 136. The first input of comparator 128 receives a divided voltage VB. The data input of the flip flop 130 is coupled to the output of the comparator 128. The clock input terminal of the counter 132 is coupled to the temporary data output terminal of the flip-flop 130. The input of the digital to analog converter 134 is coupled to the counter 132 output.
比較器128比較分壓電壓VB與前一個週期所偵測的波峰訊號Vpeak。在取樣脈波S2的每一個週期期間,正反器130檢測比較器128所輸出的邏輯位準,若是高邏輯位準則表示這個週期的分壓電壓VB的峰值比之前週期的峰值皆高,接著計數器132的計數增加一次,並輸出N位元的計數值Fdp[0:n-1]。數位至類比轉換器134對計數值Fdp[0:n-1]執行數位至類比的轉換,以提供類比型式的波峰訊號Vpeak給比較器128的第二輸入端。比較器128可以再次比較分壓電壓VB與波峰訊號Vpeak。當波峰訊號Vpeak大於分壓電壓VB時,計數器132停止計數。若是分壓電壓VB的數值上升,則計數器132將繼續增加計數值。 The comparator 128 compares the divided voltage VB with the peak signal Vpeak detected in the previous cycle. During each period of the sampling pulse S2, the flip-flop 130 detects the logic level output by the comparator 128. If the high logic bit criterion indicates that the peak value of the divided voltage VB of this period is higher than the peak of the previous period, then The count of the counter 132 is incremented once, and the count value Fdp[0:n-1] of the N-bit is output. The digit to analog converter 134 performs a digital to analog conversion of the count value Fdp[0:n-1] to provide an analog type of peak signal Vpeak to the second input of the comparator 128. The comparator 128 can compare the divided voltage VB with the peak signal Vpeak again. When the peak signal Vpeak is greater than the divided voltage VB, the counter 132 stops counting. If the value of the divided voltage VB rises, the counter 132 will continue to increase the count value.
暫存器136的輸入端耦接計數器132的輸出,其輸出端輸出數位波峰值Dp[0:n-1]。波峰偵測單元124週期性地更新數位波峰值Dp[0:n-1],且在週期性地更新數位波峰值Dp[0:n-1]時,用來重置波峰偵測單元124的週期大小Tupdate需大於輸入電壓Vin的週期大小Tac,以保證能夠得到多個弦波中的最大波峰值,其中Tupdate可以為M倍的Tac。 The input of the register 136 is coupled to the output of the counter 132, and the output thereof outputs a digital peak value Dp[0:n-1]. The peak detecting unit 124 periodically updates the digital wave peak value Dp[0:n-1], and is used to reset the peak detecting unit 124 when the digital wave peak value Dp[0:n-1] is periodically updated. The period size Tupdate needs to be greater than the period size Tac of the input voltage Vin to ensure that the maximum peak value of the plurality of sine waves can be obtained, wherein Tupdate can be M times Tac.
此外,波峰偵測單元124還可包括取樣脈波產生器142、146以及延遲單元144、148。取樣脈波產生器142的輸出端耦接正反器130的時脈輸入端與延遲單元144的輸入端。延遲單元144的輸出端耦接正反器130的重置端。取樣脈波產生器146的輸出端耦接延遲單元148的輸入端。延遲單元148的輸出端耦接計數器132的重置端。取樣脈波產生器142、146的取樣脈波分別為S2、S1,且對應的週期大小分別為Tfast、Tupdate,其中週期大小的關 係為Tupdate>Tac>Tfast。 In addition, the peak detecting unit 124 may further include sampling pulse wave generators 142, 146 and delay units 144, 148. The output of the sampling pulse generator 142 is coupled to the clock input of the flip-flop 130 and the input of the delay unit 144. The output end of the delay unit 144 is coupled to the reset end of the flip flop 130. An output of the sampling pulse generator 146 is coupled to an input of the delay unit 148. The output of the delay unit 148 is coupled to the reset terminal of the counter 132. The sampling pulse waves of the sampling pulse wave generators 142 and 146 are respectively S2 and S1, and the corresponding cycle sizes are respectively Tfast and Tupdate, wherein the cycle size is closed. Is Tupdate>Tac>Tfast.
在每一個週期大小Tupdate的期間可以檢測出若干個波峰訊號Vpeak的波峰值。計數器132的數值則暫存在暫存器136,且每隔週期大小Tupdate重置所述計數器132,以重新比較分壓電壓VB與波峰訊號Vpeak。 The peak value of several peak signals Vpeak can be detected during each period of the period Tupdate. The value of the counter 132 is temporarily stored in the register 136, and the counter 132 is reset every cycle size Tupdate to re-compare the divided voltage VB and the peak signal Vpeak.
當重置所述計數器132時,暫存器136仍繼續保持計數器132前一次的數值。故,可以透過數位至類比轉換器126來產生穩定的過電流保護參考訊號Vcs_limit。 When the counter 132 is reset, the register 136 continues to hold the previous value of the counter 132. Therefore, the stable overcurrent protection reference signal Vcs_limit can be generated through the digital to analog converter 126.
圖4是根據本發明一實施例的波形示意圖。請參閱圖4。前述波峰偵測單元124使得波峰訊號Vpeak追蹤分壓電壓VB之多個弦波中的最大波峰值。取樣脈波S1每隔一個週期大小Tupdate更新過電流保護參考訊號Vcs_limit。 4 is a schematic diagram of a waveform in accordance with an embodiment of the present invention. Please refer to Figure 4. The peak detecting unit 124 causes the peak signal Vpeak to track the maximum peak value among the plurality of sine waves of the divided voltage VB. The sampling pulse S1 updates the current protection reference signal Vcs_limit every other cycle size Tupdate.
圖5是根據本發明一實施例的過電流保護參考訊號Vcs_limit與分壓電壓VB的波峰(Vpeak)兩者之間的變化圖。請參閱圖5。過電流保護參考訊號Vcs_limit與分壓電壓VB的波峰(Vpeak)變化呈現反比。當分壓電壓VB的波峰(Vpeak)變化由低值趨向高值時,過電流保護參考訊號Vcs_limit的變化係從高值往低值下降;當分壓電壓VB的波峰(Vpeak)變化由高值趨向低值時,過電流保護參考訊號Vcs_limit的變化係從低值往高值上升。 FIG. 5 is a diagram showing a change between an overcurrent protection reference signal Vcs_limit and a peak (Vpeak) of the divided voltage VB according to an embodiment of the present invention. Please refer to Figure 5. The overcurrent protection reference signal Vcs_limit is inversely proportional to the peak (Vpeak) change of the divided voltage VB. When the peak value (Vpeak) of the divided voltage VB changes from a low value to a high value, the change of the overcurrent protection reference signal Vcs_limit decreases from a high value to a low value; when the peak of the divided voltage VB changes (Vpeak) by a high value When the value is low, the change of the overcurrent protection reference signal Vcs_limit rises from a low value to a high value.
另一方面,分壓電壓VB與輸入電壓Vin具有正比例關係。因此可以理解過電流保護參考訊號Vcs_limit與輸入電壓Vin的波峰變化將呈現反比。亦即,當輸入電壓Vin的波峰變化由低值趨向高值時,過電流保護參考訊號Vcs_limit的變化係從高值往 低值下降;當輸入電壓Vin的波峰變化由高值趨向低值時,過電流保護參考訊號Vcs_limit的變化係從低值往高值上升。 On the other hand, the divided voltage VB has a proportional relationship with the input voltage Vin. Therefore, it can be understood that the overcurrent protection reference signal Vcs_limit and the peak change of the input voltage Vin will be inversely proportional. That is, when the peak change of the input voltage Vin changes from a low value to a high value, the change of the overcurrent protection reference signal Vcs_limit is from a high value. The low value decreases; when the peak change of the input voltage Vin changes from a high value to a low value, the change of the overcurrent protection reference signal Vcs_limit rises from a low value to a high value.
基於上述本發明之實施例所揭示的內容,可以彙整出一種通用的過電流保護參考訊號的提供方法。更明確地說,圖6繪示本發明一實施例的過電流保護參考訊號的提供方法的流程圖。請合併參閱圖3和圖6,本實施例之過電流保護參考訊號的提供方法可以包括以下步驟。 Based on the content disclosed in the embodiments of the present invention, a general method for providing an overcurrent protection reference signal can be summarized. More specifically, FIG. 6 is a flow chart showing a method for providing an overcurrent protection reference signal according to an embodiment of the present invention. Referring to FIG. 3 and FIG. 6, the method for providing the overcurrent protection reference signal in this embodiment may include the following steps.
根據輸入電壓Vin來提供分壓電壓VB(步驟S10)。 The divided voltage VB is supplied in accordance with the input voltage Vin (step S10).
對分壓電壓VB執行取樣及計數操作,據以產生數位波峰值Dp[0:n-1](步驟S20)。 The sampling and counting operations are performed on the divided voltage VB, whereby the digital wave peak value Dp[0:n-1] is generated (step S20).
接著,對數位波峰值Dp[0:n-1]執行數位至類比轉換,據以提供過電流保護參考訊號Vcs_limit(步驟S30)。 Next, digital-to-analog conversion is performed on the digital wave peak value Dp[0:n-1], thereby providing an overcurrent protection reference signal Vcs_limit (step S30).
此外,對分壓電壓VB執行取樣及計數操作之步驟還可包括:週期性地更新數位波峰值Dp[0:n-1]。其中,更新數位波峰值Dp[0:n-1]的週期大小Tupdate需大於交流電壓AC_IN的週期大小Tac,以保證能夠得到多個弦波中的最大波峰值,其中Tupdate可以為M倍的Tac。 Further, the step of performing the sampling and counting operations on the divided voltage VB may further include periodically updating the digital wave peak value Dp[0:n-1]. The period length Tupdate of the updated digital peak value Dp[0:n-1] needs to be greater than the period size Tac of the AC voltage AC_IN to ensure that the maximum peak value of the plurality of sine waves can be obtained, wherein Tupdate can be M times Tac .
綜上所述,在本發明中的過電流保護電路與提供過電流保護參考訊號的方法,係根據輸入電壓Vin的波峰變化來提供過電流保護參考訊號Vcs_limit。過電流保護參考訊號Vcs_limit的產生方式與變壓器T的線圈比n無關,也與輸出電壓Vout無關,從而得以解決先前技術所述及的問題。 In summary, the overcurrent protection circuit and the method for providing an overcurrent protection reference signal in the present invention provide the overcurrent protection reference signal Vcs_limit according to the peak variation of the input voltage Vin. The overcurrent protection reference signal Vcs_limit is generated independently of the coil ratio n of the transformer T, and is also independent of the output voltage Vout, thereby solving the problems described in the prior art.
雖然本發明已以實施例揭露如上,然其並非用以限定本發明,任何所屬技術領域中具有通常知識者,在不脫離本發明之 精神和範圍內,當可作些許之更動與潤飾,故本發明之保護範圍當視後附之申請專利範圍所界定者為準。 Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art without departing from the invention In the spirit and scope, the scope of protection of the present invention is subject to the definition of the scope of the appended patent application.
另外,本發明的任一實施例或申請專利範圍不須達成本發明所揭露之全部目的或優點或特點。此外,摘要部分和標題僅是用來輔助專利文件搜尋之用,並非用來限制本發明之權利範圍。 In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.
120‧‧‧過電流保護電路 120‧‧‧Overcurrent protection circuit
122‧‧‧電阻網路 122‧‧‧Resistor network
124‧‧‧波峰偵測單元 124‧‧‧Crest detection unit
126‧‧‧數位至類比轉換器 126‧‧‧Digital to analog converter
128‧‧‧比較器 128‧‧‧ comparator
130‧‧‧正反器 130‧‧‧Factor
132‧‧‧計數器 132‧‧‧ counter
134‧‧‧數位至類比轉換器 134‧‧‧Digital to analog converter
136‧‧‧暫存器 136‧‧‧ register
142‧‧‧取樣脈波產生器 142‧‧‧Sampling pulse generator
144‧‧‧延遲單元 144‧‧‧Delay unit
146‧‧‧取樣脈波產生器 146‧‧‧Sampling pulse generator
148‧‧‧延遲單元 148‧‧‧Delay unit
Dp[0:n-1]‧‧‧數位波峰值 Dp[0:n-1]‧‧‧ digital wave peak
Fdp[0:n-1]‧‧‧計數值 Fdp[0:n-1]‧‧‧ count value
R1、R2‧‧‧電阻 R1, R2‧‧‧ resistance
S1、S2‧‧‧取樣脈波 S1, S2‧‧‧ sampling pulse wave
Tac、Tfast、Tupdate‧‧‧週期大小 Tac, Tfast, Tupdate‧‧‧ cycle size
VB‧‧‧分壓電壓 VB‧‧ ‧ voltage divider
Vcs_limit‧‧‧過電流保護參考訊號 Vcs_limit‧‧‧Overcurrent protection reference signal
Vin‧‧‧輸入電壓 Vin‧‧‧Input voltage
Vpeak‧‧‧波峰訊號 Vpeak‧‧‧Crest Signal
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Cited By (3)
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TWI595343B (en) * | 2016-12-07 | 2017-08-11 | 強弦科技股份有限公司 | Power controller with configuring turn-on time according to limiting current number |
TWI675279B (en) * | 2018-06-04 | 2019-10-21 | 群光電能科技股份有限公司 | Constant power protection circuit and constant power protection method |
TWI677153B (en) * | 2018-11-21 | 2019-11-11 | 群光電能科技股份有限公司 | Switching circuit |
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Cited By (6)
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TWI595343B (en) * | 2016-12-07 | 2017-08-11 | 強弦科技股份有限公司 | Power controller with configuring turn-on time according to limiting current number |
US9985539B1 (en) | 2016-12-07 | 2018-05-29 | Joint Power Exponent, Ltd. | Power controller with turn-on time configured according to number of current limit operations |
TWI675279B (en) * | 2018-06-04 | 2019-10-21 | 群光電能科技股份有限公司 | Constant power protection circuit and constant power protection method |
US10847969B2 (en) | 2018-06-04 | 2020-11-24 | Chicony Power Technology Co., Ltd. | Constant power protection circuit and constant power protection method |
TWI677153B (en) * | 2018-11-21 | 2019-11-11 | 群光電能科技股份有限公司 | Switching circuit |
US11063428B2 (en) | 2018-11-21 | 2021-07-13 | Chicony Power Technology Co., Ltd. | Switch circuit |
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