TWI405976B - Usb port overcurrent detecting circuit - Google Patents
Usb port overcurrent detecting circuit Download PDFInfo
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- TWI405976B TWI405976B TW99116286A TW99116286A TWI405976B TW I405976 B TWI405976 B TW I405976B TW 99116286 A TW99116286 A TW 99116286A TW 99116286 A TW99116286 A TW 99116286A TW I405976 B TWI405976 B TW I405976B
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Abstract
Description
本發明係關於一種過電流偵測電路，尤指一種用於USB埠的過電流偵測電路。The invention relates to an overcurrent detecting circuit, in particular to an overcurrent detecting circuit for a USB port.
目前，USB埠已被廣泛應用於電腦主機板上，通常電腦主機板上會設計一USB埠過電流偵測電路，以在USB埠有過電流情況發生時給南橋晶片上對應的一偵測引腳發送一低電平訊號，南橋晶片根據接收到的低電平訊號切斷該USB埠並透過電腦操作系統發送一警告訊息到用戶的操作介面上，進而提醒使用者對應USB埠上的電流過大。惟，當電腦操作系統由工作狀態進入睡眠狀態時，由於5V主電源會關閉，導致南橋晶片上偵測引腳上的高電平訊號變為低電平訊號，故會誤判斷對應USB埠上有過電流發生，進而使電腦操作系統從睡眠狀態返回至工作狀態，並產生誤判斷的警告訊息。At present, USB 埠 has been widely used on computer motherboards. Usually, a USB 埠 overcurrent detection circuit is designed on the computer motherboard to give a corresponding detection pin on the south bridge wafer when an overcurrent condition occurs on the USB 埠. Sending a low level signal, the south bridge chip cuts off the USB port according to the received low level signal and sends a warning message to the user's operation interface through the computer operating system, thereby reminding the user that the current on the corresponding USB port is too large. However, when the computer operating system goes into a sleep state from the working state, since the 5V main power supply is turned off, the high level signal on the detection pin on the south bridge chip becomes a low level signal, so the corresponding USB port is misjudged. An overcurrent occurs, which causes the computer operating system to return from a sleep state to a working state, and generates a warning message of misjudgment.
鑒於以上內容，有必要提供一種可有效防止誤判斷過電流發生的USB埠的過電流偵測電路。In view of the above, it is necessary to provide an overcurrent detecting circuit of a USB port which can effectively prevent the occurrence of an overcurrent from being misjudged.
一種USB埠過電流偵測電路，用於對一主機板上的一USB埠進行過電流偵測，該USB埠過電流偵測電路包括一接收一控制訊號的控制訊號輸入端、一接收一主電源的主電壓端、一接收一備用電源的備用電壓端、一輸出偵測訊號的偵測訊號輸出端、一保險絲、一二極體、一電阻及一電開關，該主電壓端透過該保險絲接至該二極體的陽極及連接至該USB埠的電源引腳，該二極體的陰極連接至該偵測訊號輸出端，該電阻連接在該偵測訊號輸出端與地之間，該控制訊號輸入端連接至該電開關的控制端，該電開關的第一端連接該備用電壓端，該電開關的第二端連接至該偵測訊號輸出端，當該主機板在正常工作時，該控制訊號控制該電開關截止，此時如果流經該USB埠的電源引腳的電流大於一預設值時，該保險絲斷路，該偵測訊號為低電平控制主機板斷開該USB埠的訊號連接，當該主機板在休眠狀態時，該控制訊號控制該電開關導通，此時該偵測訊號始終保持高電平。A USB 埠 overcurrent detection circuit for overcurrent detection of a USB port on a motherboard, the USB 埠 overcurrent detection circuit includes a control signal input terminal for receiving a control signal, and a receiving one master a main voltage terminal of the power source, a standby voltage terminal receiving a standby power source, a detection signal output terminal for outputting a detection signal, a fuse, a diode, a resistor and an electric switch, wherein the main voltage terminal passes through the fuse Connected to the anode of the diode and the power pin connected to the USB port, the cathode of the diode is connected to the detection signal output end, and the resistor is connected between the detection signal output end and the ground, The control signal input end is connected to the control end of the electric switch, the first end of the electric switch is connected to the standby voltage end, and the second end of the electric switch is connected to the detection signal output end, when the motherboard is in normal working condition The control signal controls the power switch to be turned off. At this time, if the current flowing through the power port of the USB port is greater than a predetermined value, the fuse is disconnected, and the detection signal is low level to control the motherboard to disconnect the USB.埠 讯 signal When the motherboard in Sleep mode, the control signal controls the power switch is turned on, at this time the detection signal is kept high.
相較習知技術，該USB埠過電流偵測電路在主機板在休眠狀態時，透過該控制訊號控制該電開關導通，進而使該備用電壓端上的備用電源控制該偵測訊號始終保持高電平，故此時不會因為該主電壓端上無電壓而發生誤判斷該USB埠上過電流的情形。Compared with the prior art, the USB 埠 overcurrent detection circuit controls the electrical switch to be turned on by the control signal when the motherboard is in the sleep state, so that the standby power control on the standby voltage terminal always keeps the detection signal high. The level is such that there is no erroneous determination of the overcurrent on the USB port due to no voltage on the main voltage terminal.
請參考圖1，本發明USB埠過電流偵測電路10設於一電腦主機板上，用於偵測該主機板上一USB埠20的電源引腳VCC上流經的電流，並在該電源引腳VCC上的電流超過預設值時，通知一南橋晶片30進行後續操作。該USB埠過電流偵測電路10的較佳實施方式包括一控制訊號輸入端A、一主電壓端Vcc、一備用電壓端Vsb、一偵測訊號輸出端B、一保險絲FS、三個電容C1-C3、一二極體D、四個電阻R1-R4、一電開關如一PNP型電晶體Q。Referring to FIG. 1 , the USB 埠 overcurrent detecting circuit 10 of the present invention is disposed on a computer motherboard for detecting a current flowing through a power pin VCC of a USB 埠 20 on the motherboard, and is used in the power supply. When the current on the foot VCC exceeds a preset value, a south bridge wafer 30 is notified to perform subsequent operations. The preferred embodiment of the USB 埠 overcurrent detecting circuit 10 includes a control signal input terminal A, a main voltage terminal Vcc, a standby voltage terminal Vsb, a detection signal output terminal B, a fuse FS, and three capacitors C1. -C3, a diode D, four resistors R1-R4, an electrical switch such as a PNP-type transistor Q.
該主電壓端Vcc用於接收該主機板上的一主電源(如5V主電源)，該主電壓端Vcc還透過該電容C1接地，還透過該保險絲FS連接至該二極體D的陽極，該二極體D的陰極透過該電阻R1連接至該偵測訊號輸出端B。該兩電容C2及C3分別連接在該二極體D的陽極及地之間，該USB埠20的電源引腳VCC連接至該二極體D的陽極。該電阻R2連接在該偵測訊號輸出端B與地之間。該控制訊號輸入端A與該南橋晶片30的一控制引腳如重定引腳PCIRST#相連，以在電腦開機上電後接收一高電平訊號及在電腦關機後接收一低電平訊號。該控制訊號輸入端A還透過該電阻R4連接至該電晶體Q的基極，該電晶體Q的射極連接該備用電壓端Vsb以接收該主機板上的一備用電源(如3.3V備用電源)。該電晶體Q的集極透過電阻R3連接至該偵測訊號輸出端B。該偵測訊號輸出端B還連接至該南橋晶片30的一偵測引腳USB_OC2_3，當該偵測引腳USB_OC2_3接收到的電壓訊號大於一預設電壓(如0.3V)時，表明該USB埠20的電源引腳VCC上流經的電流未超過預設值，當該偵測引腳USB_OC2_3接收到的電壓訊號小於等於該預設電壓時，表明該USB埠20的電源引腳VCC上流經的電流超過了預設值，此時南橋晶片30會透過USB控制器(未示出)斷開該USB埠20與電腦主機板的訊號連接。The main voltage terminal Vcc is used for receiving a main power source (such as a 5V main power source) on the motherboard. The main voltage terminal Vcc is also grounded through the capacitor C1, and is also connected to the anode of the diode D through the fuse FS. The cathode of the diode D is connected to the detection signal output terminal B through the resistor R1. The two capacitors C2 and C3 are respectively connected between the anode of the diode D and the ground, and the power pin VCC of the USB port 20 is connected to the anode of the diode D. The resistor R2 is connected between the detection signal output terminal B and the ground. The control signal input terminal A is connected to a control pin of the south bridge chip 30, such as the reset pin PCIRST#, to receive a high level signal after the computer is powered on and to receive a low level signal after the computer is turned off. The control signal input terminal A is also connected to the base of the transistor Q through the resistor R4. The emitter of the transistor Q is connected to the standby voltage terminal Vsb to receive a backup power supply on the motherboard (such as a 3.3V standby power supply). ). The collector of the transistor Q is connected to the detection signal output terminal B through a resistor R3. The detection signal output terminal B is also connected to a detection pin USB_OC2_3 of the south bridge chip 30. When the voltage signal received by the detection pin USB_OC2_3 is greater than a predetermined voltage (such as 0.3V), the USB port is indicated. The current flowing through the power supply pin VCC of 20 does not exceed the preset value. When the voltage signal received by the detection pin USB_OC2_3 is less than or equal to the preset voltage, the current flowing through the power supply pin VCC of the USB port 20 is indicated. When the preset value is exceeded, the south bridge chip 30 disconnects the signal connection between the USB port 20 and the computer motherboard through a USB controller (not shown).
具體工作原理如下：當電腦主機板處於正常工作時，南橋晶片30的重定引腳PCIRST#為高電平訊號，故該電晶體Q處於截止狀態，如果該USB埠20上的電源引腳VCC上流經的電流未超過預設值，該保險絲FS不會斷路，進而該偵測訊號輸出端B始終為高電平，南橋晶片30此時不會發出關斷訊號給USB控制器來斷開該USB埠20與電腦主機板的訊號連接。如果該USB埠20上的電源引腳VCC上流經的電流超過預設值，該保險絲FS處斷路，進而該偵測訊號輸出端B變為低電平，南橋晶片30此時會發出關斷訊號給USB控制器來斷開該USB埠20與電腦主機板的訊號連接，同時還會發送一警告訊息到用戶的操作介面上，進而提醒使用者對應USB埠上的電流過大。The specific working principle is as follows: When the computer motherboard is in normal operation, the reset pin PCIRST# of the south bridge chip 30 is a high level signal, so the transistor Q is in an off state, if the power pin VCC on the USB port 20 is high. The current does not exceed the preset value, the fuse FS does not open, and the detection signal output B is always at a high level, and the south bridge chip 30 does not issue a shutdown signal to the USB controller to disconnect the USB.埠20 is connected to the signal of the computer motherboard. If the current flowing through the power supply pin VCC on the USB port 20 exceeds a preset value, the fuse FS is disconnected, and the detection signal output terminal B becomes a low level, and the south bridge chip 30 will issue a shutdown signal at this time. The USB controller is disconnected from the USB port 20 and the computer motherboard, and a warning message is sent to the user's operation interface to remind the user that the current on the USB port is too large.
當電腦主機板由開機狀態進入休眠狀態時，該主電壓端Vcc上將無電壓訊號，而該備用電壓端Vsb仍存在電壓訊號，此時南橋晶片30的重定引腳PCIRST#變為低電平訊號，故該電晶體Q處於導通狀態，儘管此時主電壓端Vcc上將無電壓訊號，該偵測訊號輸出端B也將始終保持高電平狀態，故在電腦主機板由開機狀態進入休眠狀態後，不會出現誤判斷該USB埠20上的電源引腳VCC上流經的電流超過預設值的情況發生。其它實施方式中，該控制訊號輸入端A接收的控制訊號也可以來自主機板的其他元件，只要該控制訊號在主機板正常工作時可以控制該電開關截止，而在休眠狀態時控制該電開關導通即可。When the computer motherboard enters the sleep state from the power-on state, there is no voltage signal on the main voltage terminal Vcc, and the standby voltage terminal Vsb still has a voltage signal. At this time, the reset pin PCIRST# of the south bridge chip 30 becomes a low level. Signal, so the transistor Q is in the on state, although there will be no voltage signal on the main voltage terminal Vcc at this time, the detection signal output terminal B will always remain high state, so the computer motherboard enters the sleep state from the power on state. After the status, there is no misjudation that the current flowing through the power supply pin VCC on the USB port 20 exceeds a preset value. In other embodiments, the control signal received by the control signal input terminal A may also be from other components of the motherboard, as long as the control signal can control the electrical switch to be turned off when the motherboard is working normally, and the electrical switch is controlled during the sleep state. Turn it on.
綜上所述，本發明符合發明專利要件，爰依法提出專利申請。惟，以上所述者僅為本發明之較佳實施例，舉凡熟悉本案技藝之人士，在爰依本發明精神所作之等效修飾或變化，皆應涵蓋於以下之申請專利範圍內。In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.
10．．．USB埠過電流偵測電路10. . . USB埠 overcurrent detection circuit
20．．．USB埠20. . . USB埠
30．．．南橋晶片30. . . South Bridge Chip
A．．．控制訊號輸入端A. . . Control signal input
Vcc．．．主電壓端Vcc. . . Main voltage terminal
Vsb．．．備用電壓端Vsb. . . Standby voltage terminal
B．．．偵測訊號輸出端B. . . Detection signal output
FS．．．保險絲FS. . . fuse
C1-C3．．．電容C1-C3. . . capacitance
D．．．二極體D. . . Dipole
R1-R4．．．電阻R1-R4. . . resistance
Q．．．電晶體Q. . . Transistor
圖1係本發明USB埠過電流偵測電路較佳實施方式與一南橋晶片及一USB埠相連的電路圖。1 is a circuit diagram of a preferred embodiment of a USB 埠 overcurrent detecting circuit of the present invention connected to a south bridge chip and a USB port.
10．．．USB埠過電流偵測電路10. . . USB埠 overcurrent detection circuit
20．．．USB埠20. . . USB埠
30．．．南橋晶片30. . . South Bridge Chip
A．．．控制訊號輸入端A. . . Control signal input
Vcc．．．主電壓端Vcc. . . Main voltage terminal
Vsb．．．備用電壓端Vsb. . . Standby voltage terminal
B．．．偵測訊號輸出端B. . . Detection signal output
FS．．．保險絲FS. . . fuse
C1-C3．．．電容C1-C3. . . capacitance
D．．．二極體D. . . Dipole
R1-R4．．．電阻R1-R4. . . resistance
Q．．．電晶體Q. . . Transistor
Claims (6)
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| Application Number | Priority Date | Filing Date | Title |
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| TW99116286A TWI405976B (en) | 2010-05-21 | 2010-05-21 | Usb port overcurrent detecting circuit |
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| TW99116286A TWI405976B (en) | 2010-05-21 | 2010-05-21 | Usb port overcurrent detecting circuit |
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| TW201142309A TW201142309A (en) | 2011-12-01 |
| TWI405976B true TWI405976B (en) | 2013-08-21 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992007402A1 (en) * | 1990-10-12 | 1992-04-30 | Raychem Limited | Circuit protection arrangement |
| TW307058B (en) * | 1995-12-30 | 1997-06-01 | zhao-zheng Lu | Electric protection switch |
| US6714016B2 (en) * | 2000-02-17 | 2004-03-30 | International Business Machines Corporation | Method for displaying information concerning power consumption and electronic device |
| US6747860B2 (en) * | 2002-08-07 | 2004-06-08 | Lsi Logic Corporation | Power-supply feedthrough protection circuit for 5-volt failsafe CMOS drivers |
| TW200724935A (en) * | 2005-12-16 | 2007-07-01 | Hon Hai Prec Ind Co Ltd | Tester for USB ports |
-
2010
- 2010-05-21 TW TW99116286A patent/TWI405976B/en not_active IP Right Cessation
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992007402A1 (en) * | 1990-10-12 | 1992-04-30 | Raychem Limited | Circuit protection arrangement |
| TW307058B (en) * | 1995-12-30 | 1997-06-01 | zhao-zheng Lu | Electric protection switch |
| US6714016B2 (en) * | 2000-02-17 | 2004-03-30 | International Business Machines Corporation | Method for displaying information concerning power consumption and electronic device |
| US6747860B2 (en) * | 2002-08-07 | 2004-06-08 | Lsi Logic Corporation | Power-supply feedthrough protection circuit for 5-volt failsafe CMOS drivers |
| TW200724935A (en) * | 2005-12-16 | 2007-07-01 | Hon Hai Prec Ind Co Ltd | Tester for USB ports |
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| TW201142309A (en) | 2011-12-01 |
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