Power input automatic switching circuit of server BMC

Abstract

The utility model relates to the technical field of server BMCs (Baseboard Management Controller), in particular to a power supply input automatic switching circuit of a server BMC. Comprising an input power supply VCC12VDCIN, a resistor PR104, a resistor PR105, a resistor PR106, a voltage chip IC PQ10, a comparator IC LM358 PU2B, a resistor PR30, a resistor PR34, a filter capacitor PC11, a current limiting resistor PR27, an MOS tube PQ15, a pull-up resistor PR107, an MOS tube PQ16, a pull-up resistor PR109, a logic AND gate IC U11, a pull-down resistor PR110, a filter capacitor C2020, a DC-DC power supply chip U2001, a filter capacitor C2015, a filter capacitor C2016, a bootstrap capacitor C2014, an output inductor L10, an output filter capacitor C10408, an output filter capacitor C10409, an output filter capacitor C2018 and an output filter capacitor C2019. According to the utility model, the compatible design of different voltage values of 12V and 5V of the input power supply can be realized, and the reliability of BMC single board power supply is satisfied.

Description

Technical Field

[0001] The utility model relates to the technical field of server BMC, in particular to an automatic switching circuit for power input of a server BMC. Background Art

[0002] With the development of cloud gaming and cloud esports, a new stacked device format, the PC farm, has emerged. This deploys traditional PCs in standard cabinets, achieving computing power second only to that of data centers at a low cost and with high flexibility. However, in practical applications, PC farms use either CRPS or FLEX power supplies, while traditional general-purpose BMC modules require a standby power supply, essentially operating in a single-power supply mode. Replacing the power module also requires replacing the BMC module, which lacks compatibility with other power supplies, such as 12V and 5V. This presents compatibility issues. To address this, we propose an automatic power input switching circuit for server BMCs. Utility Model Content

[0003] The main purpose of the utility model is to provide a server BMC power input automatic switching circuit, including: input power VCC12V_DCIN, resistor PR104, resistor PR105, resistor PR106, voltage chip IC PQ10, comparator ICLM358 PU2B, resistor PR30, resistor PR34, filter capacitor PC11, current limiting resistor PR27, MOS tube PQ15, pull-up resistor PR107, MOS tube PQ16, pull-up resistor PR109, logic AND gate IC U11, pull-down resistor PR110, filter capacitor C2020, DC-DC power supply chip U2001, filter capacitor C2015, filter capacitor C2016, bootstrap capacitor C2014, output inductor L10, output filter capacitor C10408, output filter capacitor C10409, output filter capacitor C2018, output filter capacitor C2019, power supply output feedback loop resistor R2017, power supply output feedback loop resistor R2019, pull-down resistor PR20, pull-down resistor PR19, pull-down capacitor C10410, MOS transistor PQ17, MOS transistor PQ18, voltage divider resistor PR118, voltage divider resistor PR117, voltage divider resistor PR17, voltage divider resistor PR18, filter capacitor PC18, filter capacitor PC19, PMOS U90018.

[0004] Preferably, the input power supply VCC12V_DCIN is connected to the voltage chip IC PQ10 that generates the reference voltage through resistors PR104, PR105, and PR106, and generates a 2.5V reference voltage VREF_2.5V that is connected to the 6th pin of the comparator IC LM358 PU2B.

[0005] Preferably, the input power supply VCC12V_DCIN is connected to the 5th pin of the comparator IC LM358 PU2B through the voltage divider generated by resistors PR30, PR34 and filter capacitor PC11; the input power supply VCC12V_DCIN is connected to the comparator IC LM358 PU2B through the current limiting resistor PR27 to provide working power for the comparator IC LM358 PU2B, the 4th pin of the comparator IC LM358 PU2B is connected to GND, and the 1, 2, and 3 pins of the comparator IC LM358 PU2B are not used and are directly left floating.

[0006] Preferably, the 7pin of the comparator IC LM358 PU2B outputs a high level to the G pole of the MOS tube PQ15, the D pole of the MOS tube PQ15 is connected to the pull-up resistor PR107, the other end of the pull-up resistor PR107 is connected to the power supply +3VSB, the D pole of the MOS tube PQ15 is connected to the G pole of the MOS tube PQ16, and the D pole of the MOS tube PQ16 is connected to the power supply +3VSB through the pull-up resistor PR109.

[0007] Preferably, the D pole of the MOS tube PQ16 is connected to the 2nd pin of the logic AND gate IC U11, the 1st pin of the logic AND gate IC U11 is connected to the GPIO of the MCU, the 5th pin of the logic AND gate IC U11 is connected to the power supply VCC3V3_SYS to provide working power for the logic AND gate IC U11, and the 4th pin of the logic AND gate IC U11 is the logic AND gate output pin, which is connected to the 4th pin enable pin of the DC-DC power supply chip U2001 through the pull-down resistor PR110 and the filter capacitor C2020.

[0008] Preferably, the input power supply VCC12V_DCIN is connected to the power input 1pin of the DC-DC power supply chip U2001 through the filter capacitors C2015 and C2016, the 6pin of the DC-DC power supply chip U2001 and the bootstrap capacitor C2014 are connected to the output inductor L2014, and then connected to the output filter capacitors C10408, C10409, C2018, and C2019, and the power supply output feedback loop resistor R2017 and the power supply output feedback loop resistor R2019 are connected to the output inductor L2014 and the output filter capacitor.

[0009] Preferably, the input power supply VCC12V_DCIN passes through the pull-down resistor PR20, and then passes through the RC delay circuit composed of PR19 and C10410, and is connected to the G pole of the MOS tube PQ17. The input power supply VCC12V_DCIN is connected to the G pole of the MOS tube PQ18 after being divided by the voltage dividing resistor PR118 and PR117. The input power supply VCC12V_DCIN passes through the filter capacitors PC18 and PC19, and then is divided by the voltage dividing resistors PR17 and PR18 before being connected to the PMOS U90018.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The utility model uses a regulated power supply to provide a stable and precise voltage VREF_2.5V as a reference precise voltage for the comparator. The comparator's function is used to compare the positive and negative voltages. With the negative voltage as the reference point, the positive voltage is compared with the negative power supply voltage through input voltage division to control the high and low changes of the comparator's 7th pin output level. When the input power is 5V, that is, the input power voltage is lower than 7.5V, the comparator 5pin voltage is lower than 2.5V, then the comparator 7pin outputs a low level, VCC5_EN is high, the PMOS U90018 Vgs < 0 turns on, VCC12_EN is low, and the DC-DC power chip stops working. When the input power is 12V (> 7.5V), the comparator 7pin outputs a high level of 11V, then VCC5_EN is low, the PMOS U90018 Vgs = 3.3V> 0 turns off, and VCC12_EN is high, the DC-DC power chip starts working, converting the input VCC12_DCIN (12V) to VCC5V0_SYS (5V) power. The comparator compares the input power voltage value with the reference voltage and automatically adjusts the comparator 7pin voltage change according to the different input power voltage values, thus achieving a compatible design with different input power supply voltage values ​​of 12V and 5V, ensuring the reliability of the BMC board power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a first-stage step-down circuit of the utility model;

[0013] Figure 2 This is a schematic diagram of the first-stage step-down circuit of the utility model;

[0014] Figure 3 This is a schematic diagram of the differential amplifier acquisition circuit of the utility model. DETAILED DESCRIPTION

[0015] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the following is a detailed description of the specific implementation method, structure, characteristics and effects of the present invention in combination with the accompanying drawings and preferred embodiments.

[0016] See also Figures 1 to 3 This embodiment provides a server BMC power input automatic switching circuit, including: input power supply VCC12V_DCIN, resistor PR104, resistor PR105, resistor PR106, voltage chip IC PQ10, comparator ICLM358 PU2B, resistor PR30, resistor PR34, filter capacitor PC11, current limiting resistor PR27, MOS transistor PQ15, pull-up resistor PR107, MOS transistor PQ16, pull-up resistor PR109, logic AND gate IC U11, pull-down resistor PR110, filter capacitor C2020, DC-DC power supply chip U2001, filter capacitor C2015, filter capacitor C2016, bootstrap capacitor C2014, output inductor L10, output filter capacitor C10408, output filter capacitor C10409, output filter capacitor C2018, output filter capacitor C2019, power supply output feedback loop resistor R2017, power supply output feedback loop resistor R2019, pull-down resistor PR20, pull-down resistor PR19, pull-down capacitor C10410, MOS transistor PQ17, MOS transistor PQ18, voltage divider resistor PR118, voltage divider resistor PR117, voltage divider resistor PR17, voltage divider resistor PR18, filter capacitor PC18, filter capacitor PC19, PMOS U90018.

[0017] The voltage chip IC PQ10 can be used as a regulated power supply to provide a stable and accurate voltage VREF_2.5V;

[0018] The input power supply VCC12V_DCIN is connected to the voltage chip IC PQ10 that generates the reference voltage through resistors PR104, PR105, and PR106, generating a 2.5V reference voltage VREF_2.5V connected to the 6th pin of the comparator IC LM358 PU2B. The input power supply VCC12V_DCIN is connected to the 5th pin of the comparator IC LM358PU2B through the voltage divider generated by resistors PR30, PR34 and filter capacitor PC11; the input power supply VCC12V_DCIN is connected to the comparator IC LM358 PU2B through the current limiting resistor PR27 to provide working power for the comparator IC LM358 PU2B. The 4th pin of the comparator IC LM358 PU2B is connected to GND. The 1st, 2nd, and 3rd pins of the comparator IC LM358 PU2B are not used and are directly floating. PU2B's 7pin compares the voltage value of 5pin with the reference 2.5V voltage of 6pin. When the input power supply VCC12V_DCIN is higher than 7.5V, the comparator ICLM358 PU2B's 5pin voltage value is higher than 2.5V, and the comparator IC LM358 Pin 7 of PU2B outputs a high level to the G electrode of MOS transistor PQ15. At this time, Vgs (the voltage difference between the gate and source) of MOS transistor PQ15 is greater than 0, and the DS electrodes are turned on. The D electrode of MOS transistor PQ15 is connected to the pull-up resistor PR107, and the other end of the pull-up resistor PR107 is connected to the power supply +3VSB. At this time, because Vgs is greater than 0, VCC5_EN is at a low level. The D electrode of MOS transistor PQ15 is connected to the G electrode of MOS transistor PQ16. Because VCC5_EN is low, Vgs of MOS transistor PQ16 is less than or equal to 0, and the D and S electrodes of MOS transistor PQ16 are cut off. The D electrode of MOS transistor PQ16 is connected to the power supply +3VSB through pull-up resistor PR109. At this time, signal VCC12_EN is a high level of 3.3V.

[0019] The D pole of MOS tube PQ16 is connected to the 2nd pin of logic AND gate IC U11. The 1st pin of logic AND gate IC U11 is connected to the GPIO of MCU. GPIO outputs high level after MCU works. The 5th pin of logic AND gate IC U11 is connected to the power supply VCC3V3_SYS to provide working power for logic AND gate IC U11. The 4th pin of logic AND gate IC U11 is the output pin of logic AND gate. When both 1st and 2nd pins are high, the output is high. It is connected to the 4th pin enable pin of DC-DC power supply chip U2001 through pull-down resistor PR110 and filter capacitor C2020. The input power supply VCC12V_DCIN is connected to the power input 1st pin of DC-DC power supply chip U2001 through filter capacitors C2015 and C2016. The bootstrap capacitor C2014 of 1st and 6th pins of DC-DC power supply chip U2001 ensures that the upper and lower bridge MOS inside U2001 can switch normally. Through, the 6pin of the DC-DC power supply chip U2001 and the bootstrap capacitor C2014 are connected to the output inductor L2014, and then connected to the output filter capacitors C10408, C10409, C2018, and C2019. The power supply output feedback loop resistor R2017 and the power supply output feedback loop resistor R2019 are connected to the output inductor L2014 and the output filter capacitor. The output voltage is fed back to the DC-DC power supply chip U2001 through resistance voltage division. The output power supply is continuously adjusted according to the feedback voltage value to ensure that the output voltage VCCV_SYS is 5V.

[0020] When the input power supply VCC12V_DCIN is lower than 7.5V, the 5pin voltage value of the comparator IC LM358 PU2B is lower than 2.5V, and the 7pin of PU2 outputs a low level. In this way, VCC12_EN is low, and the DC-DC power supply chip U2001 stops working because the 1pin EN signal is low. At this time, VCC5_EN is high, passing through the pull-down resistor PR20, and then through the RC delay circuit composed of PR19 and C10410, and connected to the G pole of the MOS tube PQ17. The input power supply VCC12V_DCIN is connected to the G pole of the MOS tube PQ18 after being divided by the voltage divider resistors PR118 and PR117. The input power supply VCC12V_DCIN passes through the filter capacitors PC18 and PC19, and then through the voltage divider resistors PR17 and PR18 before being connected to the PMOS U90018, since the G pole voltage of MOS tube PQ18 is lower than 1V at this time, Vgs of MOS tube PQ18 is less than 1V, and D pole and S pole of MOS tube PQ18 are cut off, ensuring that Vgs of MOS tube PQ17 is 3.3V>0V at this time, D pole and S pole of MOS tube PQ17 are turned on, so the point connected to MOS tube PQ17 and PR17 is equivalent to being connected to GND, resulting in the input power supply VCC12V_DCIN passing through filter capacitors PC18 and PC19, and then divided by voltage divider resistors PR17 and PR18 to reach PMOS U90018. The voltage is about 1V, so PMOS Vgs of U90018 is less than 0, and then a conductive contact is formed between pins 1, 2, 3 and pins 5, 6, 7, and 8 of PMOSU90018. The input power VCC12V_DCIN produces the power VCC5V0_SYS through PMOSU90018. At this time, VCC5V0_SYS≈VCC12V_DCIN.

[0021] It should be noted that BMC stands for baseboard management controller and GPIO stands for general purpose input and output.

[0022] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A server BMC power input automatic switching circuit, characterized in that: include: Input power supply VCC12V_DCIN, resistors PR104, PR105, PR106, voltage chip IC PQ10, comparator IC LM358 PU2B, resistors PR30, PR34, filter capacitor PC11, current-limiting resistor PR27, MOS transistor PQ15, pull-up resistor PR107, MOS transistor PQ16, pull-up resistor PR109, logic AND gate IC U11, pull-down resistor PR110, filter capacitor C2020, DC-DC power supply chip U2001, filter capacitor C2015, filter capacitor C2016, bootstrap capacitor C2014, output inductor L10, output filter capacitor C10408, output filter capacitor C10409, output filter capacitor C2018, output filter capacitor C2019, power supply output feedback loop resistor R2017, power supply output feedback loop resistor R2019, pull-down resistor PR20, pull-down resistor PR19, pull-down capacitor C10410, MOSFET PQ17, MOSFET PQ18, voltage divider resistor PR118, voltage divider resistor PR117, voltage divider resistor PR17, voltage divider resistor PR18, filter capacitor PC18, filter capacitor PC19, PMOS U90018; Among them, the input power supply VCC12V_DCIN is connected to the voltage chip IC PQ10 that generates the reference voltage through resistors PR104, PR105, and PR106, generating a 2.5V reference voltage VREF_2.5V connected to the 6th pin of the comparator IC LM358 PU2B; the input power supply VCC12V_DCIN is connected to the 5th pin of the comparator IC LM358 PU2B through the voltage divider generated by resistors PR30, PR34 and filter capacitor PC11; the input power supply VCC12V_DCIN is connected to the comparator IC LM358PU2B through the current limiting resistor PR27 to provide working power for the comparator IC LM358 PU2B, the 4th pin of the comparator IC LM358 PU2B is connected to GND, and the 1st, 2nd, and 3rd pins of the comparator IC LM358 PU2B are not used and are directly left floating; the comparator IC LM358 Pin 7 of PU2B outputs a high level to the G-pole of MOS tube PQ15. The D-pole of MOS tube PQ15 is connected to the pull-up resistor PR107. The other end of the pull-up resistor PR107 is connected to the power supply +3VSB. The D-pole of MOS tube PQ15 is connected to the G-pole of MOS tube PQ16. The D-pole of MOS tube PQ16 is connected to the power supply +3VSB through the pull-up resistor PR109. The D-pole of MOS tube PQ16 is connected to the 2nd pin of logic AND gate IC U11. Pin 1 of logic AND gate ICU11 is connected to the GPIO of MCU. Pin 5 of logic AND gate IC U11 is connected to the power supply VCC3V3_SYS to provide working power for logic AND gate ICU11. Pin 4 of U11 is the logic AND gate output pin, which is connected to the 4-pin enable pin of the DC-DC power supply chip U2001 through the pull-down resistor PR110 and the filter capacitor C2020; the input power VCC12V_DCIN is connected to the power input 1pin of the DC-DC power supply chip U2001 through the filter capacitors C2015 and C2016, the 6-pin of the DC-DC power supply chip U2001 and the bootstrap capacitor C2014 are connected to the output inductor L2014, and then connected to the output filter capacitors C10408, C10409, C2018, C2019, and the power supply output feedback loop resistor R2017 and the power supply output feedback loop resistor R2019 are connected to the output inductor L2014 and the output filter capacitor; the input power supply VCC12V_DCIN passes through the pull-down resistor PR20, then through the RC delay circuit composed of PR19 and C10410, and is connected to the G terminal of the MOS tube PQ17. The input power supply VCC12V_DCIN is divided by the voltage divider resistor PR118 and PR117, and then connected to the G terminal of the MOS tube PQ18. The input power supply VCC12V_DCIN passes through the filter capacitors PC18 and PC19, and then through the voltage divider resistors PR17 and PR18 to connect to the PMOS U90018.

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