TWI726332B - Motherboard battery detection device - Google Patents

Abstract

A motherboard battery detection device, comprising a transistor, a first resistor, a second resistor, a baseboard management controller, and a voltage follower, the baseboard management controller controls the transistor is turned on or turned off, the voltage follower receives a first input voltage from the second resistor and receives an identical second input voltage, and outputs the same voltage as the second input voltage to the baseboard management controller, the baseboard management controller receives a first output voltage from the voltage follower, when the transistor is not conducting, the substrate baseboard controller receives a second output voltage from the voltage follower when the transistor is switched to be conductive, and the baseboard management controller compares the first output voltage with whether the difference of the second output voltage is greater than a predetermined voltage value to determine whether the battery is not present.

Description

Motherboard battery detection device

The present invention relates to a power detection device, in particular to a detection device for a motherboard battery.

The existing server has a CMOS (Complementary Metal-Oxide-Semiconductor) RAM (Random Access Memory) chip for reading and writing data on one of its motherboards and storing the current hardware-related configuration of the system. Referred to as), the CMOS RAM chip uses a real time clock (RTC; Real Time Clock) to maintain the current time. When the server power is turned off, the CMOS RAM chip uses a battery on the motherboard as shown in Figure 1. 21 receives electric energy to maintain the state where the real-time clock can be read, and retains the stored data. When the battery 21 fails to supply power normally, the data originally stored in the CMOS RAM chip will be lost. Therefore, the server usually monitors the power of the battery to avoid the loss of important CMOS RAM chip contents.

The existing server monitors the power of the battery 21 on its motherboard mainly It is implemented by a battery detection device, the battery detection device includes a first voltage divider 22, a transistor 23, a second voltage divider 24, and a baseboard management controller 25, the first voltage divider The device 22 includes a first resistor 221 electrically connected to the battery 21 and a second resistor 222 connected to ground. The transistor 23 includes a drain electrically connected to the first resistor 221 and a drain electrically connected to the second resistor 222. Source, and a gate electrically connected to the baseboard management controller 25 and the second voltage divider 24. The second voltage divider 24 includes a first resistor 241 electrically connected to the gate and a grounded first resistor 241 Two resistors 242. The baseboard management controller 25 includes a general purpose input and output pin (GPIO: General Purpose Input Output) 251 electrically connected to the first resistor 241 of the second voltage divider 24, and one electrically connected to the source Extremely analog-to-digital conversion unit 252.

When the battery 21 is normally powered, the transistor 23 is turned on/off controlled by the baseboard management controller 25 through the universal input/output pin 251, and the analog-to-digital conversion unit 252 can receive the relevant information through the second resistor 222 The output voltage of the battery 21, when the power of the battery 21 is zero, the transistor 23 is turned on/off controlled by the baseboard management controller 25 through the universal input/output pin 251, and the analog-to-digital conversion unit 252 passes through The second resistor 222 receives the zero output voltage related to the battery 21. However, if the battery 21 is not present on the motherboard (that is, it is not electrically connected to the first resistor 221), according to the above detection mechanism, the analog digital The voltage value received by the conversion unit 252 via the second resistor 222 is still zero volts. In other words, when zero volts are detected, it is impossible to know whether the battery is absent or the battery is exhausted. Furthermore, in order to avoid To avoid the misjudgment caused by the analog-to-digital conversion unit 252 when converting the voltage, the overall circuit needs to meet the requirement of extremely low leakage current. Therefore, the voltage divider resistance values of the first voltage divider 22 and the second voltage divider 24 must be lowered. However, Adjusting too low will cause the battery to increase its output current and consume excessive power, thereby reducing its lifespan. However, if the voltage divider resistance value is adjusted too high, the output current will decrease, making the baseboard management controller 25 analogous The power detected by the digital conversion unit 252 is too low, which may cause a misjudgment.

In summary, the existing battery detection devices for motherboard batteries mainly have the following shortcomings:

1. It is impossible to detect the absence of the battery.

2. The judgment structure of the transistor 23 will cause errors when the analog-to-digital conversion unit 252 performs the value conversion and thus misjudge the battery voltage.

Therefore, it is necessary to improve the existing battery detection device for detecting the battery on the motherboard.

Therefore, the purpose of the present invention is to provide a battery detection device for a motherboard.

Therefore, the motherboard battery detection device of the present invention is suitable for detecting a battery. The motherboard battery detection device includes a transistor, a first resistor, a second resistor, a baseboard management controller, and a voltage follower Coupler.

The transistor includes a first terminal, a grounded second terminal, and a control terminal.

The first resistor includes a first end electrically connected to the first end of the transistor, and a second end.

The second resistor includes a first end electrically connected to the second end of the first resistor, and a second end, and the second end of the second resistor is used to electrically connect the battery.

The substrate management controller is electrically connected to the control terminal of the transistor, and controls the transistor to switch to one of a conducting state and a non-conducting state.

The voltage follower includes a reverse end, a non-reverse end electrically connected to the first end of the second resistor, and an output end electrically connected to the reverse end. The first terminal receives a first input voltage, and the output terminal outputs the same voltage as the first input voltage.

When the transistor is in the non-conducting state, the substrate management controller receives a first output voltage that is directly related to the voltage output from the output terminal of the voltage follower. When the transistor is switched to the conducting state, the substrate The management controller receives a second output voltage that is positively correlated with the voltage output from the output terminal of the voltage follower, and the baseboard management controller compares whether the difference between the first output voltage and the second output voltage is greater than a predetermined value. Set the voltage value to determine whether the battery does not exist.

The effect of the present invention is that by the characteristic that the voltage follower has an overall gain value of 1, when the substrate management controller controls the conduction or non-conduction of the transistor, the detected battery voltage is transmitted to the substrate management controller and communicated with The preset voltage value is compared to judge Whether the battery is present.

21: battery

22: The first voltage divider

221: first resistance

222: second resistor

23: Transistor

24: second voltage divider

241: first resistance

242: second resistor

25: baseboard management controller

251: General-purpose input and output pins

252: Analog-to-digital conversion unit

3: battery

4: Transistor

41: first end

42: second end

43: control terminal

5: The first resistance

51: first end

52: second end

6: Second resistor

61: first end

62: second end

7: baseboard management controller

71: General-purpose input and output pins

72: Analog-to-digital conversion unit

8: Voltage follower

81: non-reverse end

82: reverse end

85: output

9: Voltage divider

91: third resistor

911: first end

912: second end

92: fourth resistor

921: first end

922: second end

Vcc: DC bias

Q1~Q13: Transistor

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: Figure 1 is a circuit diagram illustrating a conventional motherboard battery detection device; Figure 2 is a circuit diagram illustrating the present invention An embodiment of the battery detection device for the motherboard of the invention; and FIG. 3 is a circuit diagram to assist in explaining the specific methods of some circuits in this embodiment.

Referring to FIG. 2, an embodiment of the motherboard battery detection device of the present invention is suitable for detecting a battery 3. The motherboard battery detection device includes a transistor 4, a first resistor 5, a second resistor 6, A baseboard management controller 7, a voltage follower 8, and a voltage divider 9.

The transistor 4 includes a first terminal 41, a grounded second terminal 42, and a control terminal 43. The transistor 4 is an N-type MOSFET (N-type Metal Oxide Semiconductor). Field Effect Transistor), wherein the first terminal 41 is a drain, the second terminal 42 is a source, and the control terminal 43 is a gate. It should be added that the transistor 4 of this embodiment can also be a P-type MOSFET (N-type Metal Oxide). Semiconductor Field Effect Transistor), wherein the first terminal 41 is a source, the second terminal 42 is a drain, and the control terminal 43 is a gate; or a bipolar junction transistor (BJT: Bipolar Junction Transistor) , Wherein the first terminal 41 is a collector, the second terminal 42 is an emitter, and the control terminal 43 is a base.

The first resistor 5 includes a first terminal 51 and a second terminal 52. The ground terminal 51 is electrically connected to the first terminal 41 of the transistor 4.

The second resistor 6 includes a first terminal 61 and a second terminal 62. The first terminal 61 is electrically connected to the second terminal 52 of the first resistor 5, and the second terminal 62 is used to electrically connect the battery 3 .

The baseboard management controller 7 includes a universal input/output pin 71, and an analog-to-digital conversion unit 72. The universal input/output pin 71 is electrically connected to the second terminal 42 of the transistor 4, and the universal input/output pin 71 is electrically connected to the second terminal 42 of the transistor 4. The pin 71 is used to output a logic signal to the control terminal of the transistor 4. The logic signal is set by the substrate management controller 7 to change between a high level and a low level to control the transistor 4 to switch to a In one of the conducting state and the non-conducting state, the analog-to-digital conversion unit 72 is an analog-to-digital converter (ADC: Analog Digital Converter), which receives the analog voltage output from the voltage follower 8.

The voltage follower 8 is a negative feedback amplifier, and includes a non-reverse terminal 81, a reverse terminal 82, and an output terminal 85. The non-reverse terminal 81 is electrically connected to the second resistor 6 The first end 61, the reverse end 82 and the The output terminal 85 is electrically connected, so that the voltage follower 8 becomes a Unity-Gain Buffer with an overall amplifier gain of 1. Therefore, the overall amplifier gain of the voltage follower 8 is 1, and the non-inverting The terminal 81 receives a first input voltage from the first terminal 61 of the second resistor 6, and the output terminal 85 outputs the same voltage as the first input voltage. With reference to FIG. 3, the voltage follower 8 is further explained. In the detailed circuit, in this embodiment, the voltage follower 8 is implemented by using an operational amplifier model LM358 with a third resistor 91 and a fourth resistor 92.

。 The voltage divider 9 includes the third resistor 91 and the fourth resistor 92. The third resistor 91 has a first terminal 911 electrically connected to the output terminal 85 of the voltage follower 8, and a first terminal 911 electrically connected to the output terminal 85 of the voltage follower 8 The second end 912 of the analog-to-digital conversion unit 72, the fourth resistor 92 has a first end 921 electrically connected to the second end 912 of the third resistor 91, and a second end 922 that is grounded. Generally speaking, the analog The digital converter has its corresponding resolution, that is, it has the voltage range of the analog signal that can be correctly received and the corresponding number of discrete digital signals that can be output. For example, if the analog-to-digital converter is 16 bits, its The signal voltage range that can be received is between 0 and 1.8 volts. When the voltage value of the received signal is higher than 1.8 volts, it must be converted by a voltage divider resistor before it can be accurately received. Based on practical design experience In other words, the optimal voltage division value is 3/4 of the maximum value of the signal voltage range that the analog-to-digital converter can receive, that is, the ratio of the resistance value of the third resistor 91 to the fourth resistor 92 is 1:3. In the embodiment, since the voltage value of the output signal of the voltage follower 8 does not necessarily correspond to the correct receiving range of the analog-to-digital conversion unit 72, by matching the receiving voltage range of the analog-to-digital conversion unit 72, the design is adjusted The resistance values of the third resistor 91 and the fourth resistor 92 can be divided into the output voltage of the output terminal 85 of the voltage follower 8 and then transmitted to the analog-to-digital conversion unit 72, so that it can be accurately received , Assuming that the resistance value of the third resistor 91 is R ₃ , the resistance value of the fourth resistor 92 is R ₄ , and the output voltage of the output terminal is V , the voltage value of the signal received by the analog-to-digital conversion unit 72 is

.

When the transistor 4 is in the non-conducting state, the baseboard management controller 7 receives a first terminal 921 of the fourth resistor 92 that is positively correlated with the voltage output by the output terminal 85 of the voltage follower 8 Output voltage, when the transistor 4 is switched to the on state, the baseboard management controller 7 then receives from the first terminal 921 of the fourth resistor 92 a positive correlation with the output terminal 85 of the voltage follower 8 The substrate management controller 7 compares whether the difference between the first output voltage and the second output voltage is greater than a preset voltage value to determine whether the battery does not exist. When the substrate management If the comparison result of the controller 7 is yes, it is judged that the battery does not exist, and when the comparison result of the baseboard management controller 7 is no, it is judged that the battery exists, and the battery power can be further judged, as described in more detail below.

First, the baseboard management controller 7 outputs a disable signal via the universal input/output pin 71, that is, a logic signal at a low level to the control terminal 43 of the transistor 4, so that the transistor 4 No conduction, this analog-digital conversion unit 72 receives the first output voltage from the first terminal 921 of the fourth resistor 92, and then, the baseboard management controller 7 outputs an enable signal via the universal input/output pin 71, that is, a high-level The logic signal is sent to the control terminal 43 of the transistor 4, so that the transistor 4 is switched on, the analog-to-digital conversion unit 72 receives the second output voltage from the first terminal 921 of the fourth resistor 92, and the substrate management The controller 7 performs analog-to-digital conversion of the first and second output voltages via the analog-to-digital conversion unit 72 and compares the difference between the first output voltage and the second output voltage to determine whether the battery is present or has power .

Generally speaking, the DC bias voltage Vcc of the voltage follower 8 is 3 volts, and the voltage of the battery 2 is 3.3 volts when not in use. the first end 61 creates a pressure drop, in the present embodiment, the predetermined voltage value is assumed to be 1 volt, the resistance of the first resistor 5 is 10 M Ω, the resistance value of the second resistor 6 of 1 M Ω, according to whether the battery is present on the motherboard, the various conditions are listed as follows, and then the operation mechanism of this embodiment under various conditions is further discussed:

)，此時，該第一、第二輸出電壓的差值不大於該預設電壓值。 1. The battery 2 exists and can supply power normally: if the baseboard management controller 7 controls the transistor 4 to be non-conductive via the universal input and output pin 71, and the battery discharge path is equivalent to an open circuit, the analog-to-digital conversion unit 72 receives The first output voltage obtained is a voltage proportional to the voltage value of the battery 2 when it is not in use. Therefore, the first output voltage is 3.3 volts (for the convenience of description, it is assumed that the third resistor 91 and the fourth resistor 91 The voltage division ratio of the two resistors 92 is 1, that is, the resistance value of the third resistor 91 is zero); if the baseboard management controller 7 controls the transistor 4 to be turned on through the universal input and output pin 71, the analogy The second output voltage received by the digital conversion unit 72 is the divided voltage of the battery 2 at the second end 62 of the second resistor 6 (

), at this time, the difference between the first and second output voltages is not greater than the preset voltage value.

2. The battery 2 exists and the power is zero: if the baseboard management controller 7 controls the transistor 4 to be non-conductive via the universal input and output pin 71, the first output voltage received by the analog-to-digital conversion unit 72 This is the voltage of the battery 2 when it is not in use. Therefore, the first output voltage is 0 volts at this time. If the baseboard management controller 7 controls the transistor 4 to be turned on through the universal input and output pin 71, the The second output voltage received by the analog-to-digital conversion unit 72 is the divided voltage of the battery 2 at the second end 62 of the second resistor 6. Therefore, if the second output voltage is 0 volts at this time, then the first output voltage is 0 volts. The difference of a second output voltage is not greater than the preset voltage value.

3. The battery 2 does not exist: if the baseboard management controller 7 controls the transistor 4 to be non-conducting via the universal input and output pin 71, the first output voltage received by the analog-to-digital conversion unit 72 is the voltage The DC bias voltage Vcc (3 volts) of the follower 8 (that is, the non-inverting terminal 81 is regarded as an open circuit with the battery 2 and the transistor 4, so the transistors Q1~Q4 of the voltage follower 8 are not Turn on, and Q5~Q6 turn on, because The first output voltage received by the analog-to-digital conversion unit 72 is the DC bias voltage Vcc of the voltage follower 8), if the baseboard management controller 7 controls the transistor through the universal input/output pin 71 4 is on, the non-inverting terminal 81 is grounded, so the received first input voltage is zero volts, due to the virtual short (Virtual Short) characteristic, the output terminal 85 outputs a second output voltage of zero volts, At this time, the difference between the first and second output voltages is greater than the preset voltage value.

It can be seen from the above three situations that when the difference between the first output voltage and the second output voltage is greater than the preset voltage value, it means that the battery does not exist, and when the difference between the first output voltage and the second output voltage is not If the voltage is greater than the preset voltage value, it means that the battery exists, and when the first and second output voltages received by the analog-to-digital conversion unit 72 are both zero, it means that the battery power is zero. The received first and second output voltages are not zero, which means that the battery power is not zero.

In this embodiment, the substrate management controller 7 controls the conduction/non-conduction of the transistor 4 through the universal input and output pins 71, and then the analog-digital conversion unit 72 of the substrate management controller 7 receives the voltage value transmitted by the voltage follower 8 The difference in the battery status is then judged, and there are the following advantages:

1. The voltage follower 8 directly detects the voltage division of the battery 3 in the second resistor 6, without considering the leakage current of the transistor 4, and thus will not cause errors in the conversion value of the analog-to-digital conversion unit 72.

2. With the gain value of voltage follower 8 being 1, the voltage value of battery 3 can be changed The characteristics of the complete output, in conjunction with the control transistor 4 conduction or non-conduction, and then through the output value of the voltage follower 8 to determine the voltage difference of the battery 3 in these two states, respectively, it can be accurately judged that the battery 3 is present in the host The board has electricity, or the battery 3 is present on the motherboard and has no electricity, or the battery 3 does not exist on the motherboard.

In summary, the motherboard battery detection device of the present invention uses the characteristic that the voltage follower gain value is 1 to detect the voltage value of the battery when the baseboard management controller controls the conduction or non-conduction of the transistor. It is completely transmitted to the baseboard management controller, and the baseboard management controller compares the received voltage value with the preset voltage value to determine whether the battery exists, so the objective of the invention can indeed be achieved.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to Within the scope covered by the patent of the present invention.

3: battery

4: Transistor

41: first end

42: second end

43: control terminal

5: The first resistance

51: first end

52: second end

6: Second resistor

61: first end

62: second end

7: baseboard management controller

71: General-purpose input and output pins

72: Analog-to-digital conversion unit

8: Voltage follower

81: non-reverse end

82: reverse end

85: output

9: Voltage divider

91: third resistor

911: first end

912: second end

92: fourth resistor

921: first end

922: second end

Claims (9)

A motherboard battery detection device is suitable for detecting a battery. The motherboard battery detection device includes: a transistor including a first terminal, a grounded second terminal, and a control terminal; a first resistor , Including a first end electrically connected to the first end of the transistor, and a second end; a second resistor, including a first end electrically connected to the second end of the first resistor, and a second end Terminal, the second terminal of the second resistor is used to electrically connect the battery; a substrate management controller, electrically connected to the control terminal of the transistor, and controls the transistor to switch between a conducting state and a non-conducting state One of them; and a voltage follower, including a reverse end, a non-reverse end electrically connected to the first end of the second resistor, and an output end electrically connected to the reverse end, the non-reverse end A first input voltage is received from the first terminal of the second resistor, and the output terminal outputs the same voltage as the first input voltage. When the transistor is in the non-conducting state, the baseboard management controller receives a positive correlation The first output voltage of the voltage output from the output terminal of the voltage follower, when the transistor is switched in the conducting state, the baseboard management controller receives a positive correlation with the output of the output terminal of the voltage follower Voltage of the second output voltage, the baseboard management controller compares the first output voltage with the second output Whether the difference of the output voltage is greater than a preset voltage value is used to determine whether the battery does not exist. The motherboard battery detection device according to claim 1, wherein when the difference between the first output voltage and the second output voltage is greater than the preset voltage value, the battery does not exist. The motherboard battery detection device according to claim 2, wherein the first output voltage is an operating voltage of the voltage follower. The motherboard battery detection device according to claim 1, wherein when the difference between the first output voltage and the second output voltage is not greater than the preset voltage value, the battery exists. The motherboard battery detection device according to claim 1, wherein the baseboard management controller includes a universal input/output pin electrically connected to the control terminal of the transistor, and the universal input/output pin is used to output a The logic signal is sent to the control terminal of the transistor, and the logic signal is set by the substrate management controller to change between a high level and a low level. The motherboard battery detection device according to claim 1, wherein the baseboard management controller further includes an analog-to-digital conversion unit that receives the first output voltage and the second output voltage. The motherboard battery detection device according to claim 6, further comprising a voltage divider electrically connecting the output terminal of the voltage follower and the analog-to-digital conversion unit, the voltage divider according to a voltage division ratio The voltage output from the output terminal of the follower is converted into the first output voltage and the second output voltage. The motherboard battery detection device according to claim 1, wherein the voltage follower is a negative feedback amplifier. The motherboard battery detection device according to claim 7, wherein the voltage divider includes a third resistor and a fourth resistor, and the third resistor has a first resistor electrically connected to the output terminal of the voltage follower One end, and a second end electrically connected to the analog-to-digital conversion unit, the fourth resistor has a first end electrically connected to the second end of the third resistor, and a second end that is grounded. When the transistor is in In the non-conductive state, the baseboard management controller receives a first output voltage from the first terminal of the fourth resistor that is positively correlated with the voltage output from the output terminal of the voltage follower, and when the transistor is switched to the conductive In the state, the baseboard management controller receives a second output voltage from the first terminal of the fourth resistor, which is positively correlated with the output voltage of the output terminal of the voltage follower.

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