Power management circuit

Abstract

The invention discloses a power supply management circuit, and when an initial power supply suddenly powers down, a power supply capacitor in a power supply capacitor charge and discharge unit discharges, and supplies power to a system through a direct current boost unit. However, after the initial power supply is powered down, the first control unit is turned off immediately, so that the situation that the direct-current boosting unit boosts the voltage to 5V and continues to charge the power supply capacitor through the current-limiting resistor can be avoided. Meanwhile, the energy stored by the power supply capacitor is only used for meeting the power-down storage requirement of the system, and after the system completes the storage operation, almost no extra energy consumption is generated. Due to the fact that energy still exists in the power supply capacitor after the power-down storage process is finished, when the initial power supply is powered on and off frequently, the current in the current-limiting resistor is not too large, loss is reduced, and the risk that the current-limiting resistor and the power supply capacitor are burnt down is effectively reduced.

Description

Technical Field

[0001] This invention relates to the technical field of power management, specifically to a power management circuit. Background Technology

[0002] With the rapid development of industrial automation and intelligent devices, the requirements for power supply stability in electronic systems are increasing. Many critical devices (such as robotic arms, industrial controllers, and data storage units) rely on a stable power supply during operation. If the initial power supply (such as a +24V industrial power supply) suddenly fails or experiences overvoltage or undervoltage abnormalities, it may lead to data loss, functional interruption, or even hardware damage. In existing power management solutions, the power switching module typically includes a charging / discharging unit and a DC-DC boost unit. When the initial power supply is working normally, it charges the charging unit. After a sudden power failure, the power supply capacitor in the charging / discharging unit discharges to supply power to the system. After being boosted to 5V by the DC-DC boost unit, it continues to charge the power supply capacitor through a current-limiting resistor. This results in additional energy loss from the power supply capacitor. Furthermore, if the power supply capacitor capacity is insufficient, it will be unable to maintain the data storage process during power outages. However, if the power supply capacitor capacity is large, it will lead to longer charging times, larger product size, and higher costs. Moreover, this process will continue until the power outage ends and the power supply capacitor is fully discharged. After the system has finished saving the parameters, it cannot actively stop the power supply capacitor from discharging. Therefore, if the initial power supply is frequently powered on and off, it will continuously charge the power supply capacitor through the current-limiting resistor. This will generate a lot of power consumption and there is a risk of burning out the current-limiting resistor and the power supply capacitor. Summary of the Invention

[0003] This application provides a power management circuit to solve the problem of how to effectively prevent the DC boost unit from continuing to charge the power supply capacitor through the current limiting resistor after the initial power supply suddenly fails, thereby causing damage to the current limiting resistor and the power supply capacitor.

[0004] To address the aforementioned technical problems, this application provides a power management circuit, comprising: a power conversion module, a system power failure detection module, and a power switching module; A power conversion module is used to generate a preset voltage value based on a preset initial power supply and to supply power to the power switching module. The system power failure detection module is used to detect the initial power state and output a corresponding control signal to the power switching module; The power switching module includes a power supply capacitor charging and discharging unit, a DC boost unit, a first control unit, a second control unit, and a logic control unit; The input terminal of the first control unit is connected to the output terminal of the power conversion module, and is used to control the on / off state of the power conversion module and the system; the power supply capacitor charging and discharging unit is used to obtain the preset voltage value output by the power conversion module and charge the power supply capacitor; after the initial power is turned off, the system is powered through the DC boost unit and the second control unit in sequence; the DC boost unit is used to boost the voltage output by the power supply capacitor after the initial power is turned off and then power the system; the logic control unit controls the on / off state of the second control unit according to the preset input signal.

[0005] In one embodiment, the power switching module further includes a step-down unit for providing a 3.3V power supply voltage to the system.

[0006] In one embodiment, the power supply capacitor charging and discharging unit includes a 298th capacitor, a 285th resistor, a 287th resistor, and a 48th diode. One end of the 298th capacitor is connected to the negative terminal of the 48th diode, and the other end is connected to ground. The positive terminal of the 48th diode is connected to one end of the 285th resistor and the 287th resistor, respectively. The other ends of the 285th resistor and the 287th resistor are connected to a 5V power supply.

[0007] In one embodiment, the DC boost unit includes a seventeenth inductor, a forty-sixth diode, a two hundred and ninety-ninth capacitor, and a boost sub-unit. One end of the seventeenth inductor is connected to one end of the two hundred and ninety-eighth capacitor, and the other end is connected to the positive terminal of the forty-sixth diode and the first pin of the boost sub-unit. The negative terminal of the forty-sixth diode is connected to one end of the two hundred and ninety-ninth capacitor.

[0008] In one embodiment, the first control unit includes a fifteenth MOSFET, a sixteenth MOSFET, and a two hundred and eighty-second resistor. The sources of the fifteenth and sixteenth MOSFETs are connected to a 5V power supply, the drains are connected to a VCC_5V power supply, the gates are connected to one end of the two hundred and eighty-second resistor, and the other end of the two hundred and eighty-second resistor is connected to the output terminal of the system power failure detection module.

[0009] In one embodiment, the second control unit includes a seventeenth MOSFET, an eighteenth MOSFET, and a two hundred and ninety-sixth resistor. The sources of the seventeenth MOSFET and the eighteenth MOSFET are connected to the VCC-5V power supply, the drains are connected to one end of the two hundred and ninety-ninth capacitor, the gates are connected to one end of the two hundred and ninety-sixth resistor, and the other end of the two hundred and ninety-sixth resistor is connected to the output terminal of the logic control unit.

[0010] In one embodiment, the logic control unit includes a NAND gate control unit, the input of which is connected to the output of the system power failure detection module, and the output is connected to the other end of the 296th resistor.

[0011] In one embodiment, the system power failure detection module includes a voltage divider and isolation unit, a signal driving unit, and a voltage regulator unit. The input terminal of the voltage divider and isolation unit is connected to the initial power supply, and the output terminal is connected to the input terminal of the signal driving unit. It is used to divide the initial power supply and isolate the high-voltage side and the low-voltage side. The signal driving unit converts the voltage value output by the voltage divider and isolation unit into a preset voltage value and outputs a stable control signal. The input terminal of the voltage regulator unit is connected to the initial power supply, and the output terminal is connected to the input terminal of the signal driving unit. It is used to divide the initial power supply and filter out noise.

[0012] In one embodiment, the voltage divider and isolation unit includes an optocoupler, a 263rd resistor, a 265th resistor, a 268th resistor, a 270th resistor, and a 30th diode. One end of the 263rd, 265th, and 270th resistors is connected to +24VB. The other end of the 263rd and 265th resistors is connected to the 268th resistor, one end of the optocoupler, and the negative terminal of the 30th diode, respectively. The other end of the 270th resistor is connected to the 268th resistor, one end of the optocoupler, and the positive terminal of the 30th diode, respectively.

[0013] In one embodiment, the signal driving unit includes an eleventh field-effect transistor, a twelfth field-effect transistor, a 260th resistor, a 261st resistor, a 267th resistor, and a 289th capacitor. One end of the 267th resistor is connected to VCC_3V3, and the other end of the 267th resistor is connected to one end of the 289th capacitor and the gate of the eleventh field-effect transistor. The drain of the eleventh field-effect transistor is connected to one end of the 260th resistor and the gate of the twelfth field-effect transistor. The other end of the 260th resistor is connected to VCC_5V. The drain of the twelfth field-effect transistor is connected to one end of the 261st resistor, and the other end of the 261st resistor is connected to VCC_5V.

[0014] The beneficial effects of the above power management circuit are: This application coordinates the power conversion module, system power failure detection module, power supply capacitor charging / discharging unit, DC boost unit, first control unit, second control unit, and logic control unit. When the initial power supply suddenly fails, the power supply capacitor in the power supply capacitor charging / discharging unit discharges and supplies power to the system through the DC boost unit. However, after the initial power supply fails, the first control unit immediately shuts down, thus preventing the DC boost unit from boosting the voltage to 5V and then continuing to charge the power supply capacitor through the current-limiting resistor. Simultaneously, the energy stored in the power supply capacitor is only used to meet the system's power failure preservation needs; after the system completes the preservation operation, almost no additional energy is consumed. Since energy remains in the power supply capacitor after the power failure preservation process, the current in the current-limiting resistor will not be excessive when the initial power supply is frequently switched on and off, thereby reducing losses and effectively reducing the risk of the current-limiting resistor and power supply capacitor burning out. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the circuit structure of a power management circuit shown in an embodiment of this application; Figure 2 for Figure 1 This application embodiment shows a circuit diagram of a power conversion module of a power management circuit; Figure 3 for Figure 1 This application embodiment illustrates a circuit diagram of a system power failure detection module for a power management circuit; Figure 4 for Figure 1 This application embodiment shows a circuit diagram of a power switching module of a power management circuit; Figure 5 for Figure 1 This application embodiment shows a circuit diagram of an external drive power module for a power management circuit. Detailed Implementation

[0016] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0017] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediary component present. Conversely, when a component is said to be "directly" connected to another component, there is no intermediary component.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] like Figure 1 As shown, this application provides a power management circuit, including: a power conversion module 1, a system power failure detection module 2, and a power switching module 3; The power conversion module 1 is used to generate a preset voltage value based on a preset initial power supply and to supply power to the power switching module 3. When the preset voltage value includes a power supply of 5V, 3.3V, 2.5V, 1.8V, and 1.2V, the specific output voltage needs to be selected according to the power supply requirements of the chips in the system. The circuit in this application mainly uses 5V and 3.3V voltages.

[0020] The system power failure detection module 2 is used to detect the initial power state and output a corresponding control signal to the power switching module. like Figure 4 As shown, the power switching module 3 includes a power supply capacitor charging and discharging unit 31, a DC boost unit 32, a first control unit 33, a second control unit 34, and a logic control unit 35; The input terminal of the first control unit 33 is connected to the output terminal of the power conversion module 1, and is used to control the on / off state of the power conversion module 1 and the system; the power supply capacitor charging and discharging unit 31 is used to obtain the preset voltage value output by the power conversion module 1 and charge the power supply capacitor; after the initial power is turned off, the system is powered through the DC boost unit 32 and the second control unit 34 in sequence; the DC boost unit 32 is used to boost the voltage output by the power supply capacitor after the initial power is turned off and then power the system; the logic control unit 35 controls the on / off state of the second control unit 34 according to the preset input signal.

[0021] In one embodiment, the power supply capacitor charging and discharging unit 31 includes a second ninety-eighth capacitor C298, a second eighty-fifth resistor R285, a second eighty-seventh resistor R287, and a forty-eighth diode D48. One end of the second ninety-eighth capacitor C298 is connected to the negative terminal of the forty-eighth diode D48, and the other end is connected to ground. The positive terminal of the forty-eighth diode D48 is connected to one end of the second eighty-fifth resistor R285 and the second eighty-seventh resistor R287, respectively. The other ends of the second eighty-fifth resistor R285 and the second eighty-seventh resistor R287 are connected to a 5V power supply.

[0022] In one embodiment, the DC boost unit 32 includes a seventeenth inductor L17, a forty-sixth diode D46, a two hundred and ninety-ninth capacitor C299, and a boost sub-unit U35. One end of the seventeenth inductor L17 is connected to one end of the two hundred and ninety-eighth capacitor C298, and the other end is connected to the positive terminal of the forty-sixth diode D46 and the first pin of the boost sub-unit U35. The negative terminal of the forty-sixth diode D46 is connected to one end of the two hundred and ninety-ninth capacitor C299.

[0023] The seventeenth inductor L17 is the energy storage element of the DC-DC boost unit 32. It stores energy when the switch inside the boost subunit U35 is on and releases energy when it is off. It works in conjunction with the forty-sixth diode D46 to achieve the boost function, raising the low voltage of the two hundred and ninety-eighth capacitor C298 to 5V. The two hundred and ninety-ninth capacitor C299 is used to filter the ripple of the DC-DC boost unit 32. The forty-sixth diode D46 is unidirectional, preventing the boosted energy from flowing back to the two hundred and ninety-eighth capacitor C298 in the DC-DC boost unit 32, ensuring that BOOST_5V only supplies power to the system, and also participates in the energy release during the boost process. The two hundred and ninety-fourth resistor R294 and the two hundred and ninety-ninth resistor R299 are the feedback resistors of the DC-DC boost unit 32. The voltage divider circuit feeds back the BOOST_5V voltage signal to the FB terminal of the boost sub-unit U35, enabling precise adjustment of the output voltage and ensuring a stable 5V output. Resistor R297 is the power supply current-limiting resistor for boost sub-unit U35. Together with capacitor C300 for filtering, it provides a stable power supply environment for boost sub-unit U35. Boost sub-unit U35 is the core controller of DC boost unit 32. It controls the energy storage and release of inductor L17 through an internal switch. Combined with the feedback from resistors R294 and R299, it boosts the voltage of capacitor C298 to 5V. The enable terminal (EN) is controlled by C_DISCHARGE, determining the start and stop of DC boost unit 32.

[0024] In one embodiment, the first control unit 33 includes a fifteenth MOSFET Q15, a sixteenth MOSFET Q16, and a two hundred and eighty-second resistor R282. The sources of the fifteenth MOSFET Q15 and the sixteenth MOSFET Q16 are connected to a 5V power supply, the drains are connected to a VCC_5V power supply, and the gates are connected to one end of the two hundred and eighty-second resistor R282. The other end of the two hundred and eighty-second resistor R282 is connected to the output terminal of the system power failure detection module 2.

[0025] Resistor R282, the 282nd resistor, is the gate pull-down resistor for the 15th MOSFET Q15 and the 16th MOSFET Q16. It ensures reliable cutoff of the gates of the 15th MOSFET Q15 and the 16th MOSFET Q16 when there is no drive signal, and prevents false turn-on.

[0026] In one embodiment, the second control unit 34 includes a seventeenth MOSFET Q17, an eighteenth MOSFET Q18, and a two hundred and ninety-sixth resistor R296. The sources of the seventeenth MOSFET Q17 and the eighteenth MOSFET Q18 are connected to the VCC-5V power supply, the drains are connected to one end of the two hundred and ninety-ninth capacitor C299, the gates are connected to one end of the two hundred and ninety-sixth resistor R296, and the other end of the two hundred and ninety-sixth resistor R296 is connected to the output terminal of the logic control unit 35.

[0027] Resistor R296 is the gate pull-down resistor for MOSFETs Q17 and Q18. It ensures reliable cutoff of MOSFETs Q17 and Q18 when there is no drive signal, preventing false turn-on. MOSFETs Q17 and Q18 are P-channel MOSFETs controlled by PWR_MOS_B. They conduct when PWR_MOS_B is low, introducing BOOST_5V to the system power supply; they are cut off when PWR_MOS_B is high, cutting off the backup power supply path, thus serving as switching elements for backup power.

[0028] In one embodiment, the logic control unit 35 includes a NAND gate control unit U38, the input terminal of which is connected to the output terminal of the system power failure detection module 2, and the output terminal is connected to the other end of the 296th resistor R296.

[0029] NAND gate control unit U38: The core of logic control, it takes C_DISCHARGE and PWR_MOS_A signals as inputs, and outputs PWR_MOS_B through NAND logic operation to control the on / off state of the seventeenth MOSFET Q17 and the eighteenth MOSFET Q18, realizing the logic control of the backup power supply path; Capacitor C229: The power supply filter capacitor of NAND gate control unit U38, which filters out noise at the VCC terminal and ensures the stability of the logic operation of NAND gate control unit U38.

[0030] The 298th capacitor, C298, is the power supply capacitor. Under normal operation, it is charged from +5V through the 285th resistor, R285, the 287th resistor, R287, and the 48th diode, D48, to store backup power. When the power is lost, it releases the power and, after being boosted by the BOOST circuit, supplies power to the system. It is the energy source for backup power supply. Resistors R285 (285) and R287 (287): During normal operation, they limit current and control the charging current of capacitor C298 (298); when power is off, they work with MOSFETs Q15 (15) and Q16 (16) to cut off the reverse current path. Diode D48 (48): It conducts in one direction to prevent reverse current from flowing back to the +5V main power supply when capacitor C298 discharges. Boost subunit U35: The core boost element, which converts the low-voltage energy of capacitor C298 (298) into a stable 5V voltage. NAND gate control unit U38: Based on the logic combination of PWR_MOS_A and C_DISCHARGE, it outputs PWR_MOS_B to control the on / off state of MOSFETs Q17 (17) and Q18 (18).

[0031] When the initial +24VB power supply is normal, power conversion module 1 outputs a stable +5V power supply, and the circuit enters normal operation: the WR_MOS_A signal output by system power failure detection module 2 is low, and the +5V power supply directly supplies power to the system through the fifteenth MOSFET Q15 and the sixteenth MOSFET Q16; the +5V power supply charges the 298th capacitor C298 through the 285th resistor R285, the 287th resistor R287, and the 48th diode D48 to store backup energy. At this time, the DC boost unit 32 is not started, the C_DISCHARGE signal is high, the NAND gate control unit U38 outputs PWR_MOS_B high, and the seventeenth MOSFET Q17 and the eighteenth MOSFET Q18 are cut off.

[0032] When the +24VB main power supply fails or experiences an overvoltage, the system power failure detection module 2 outputs PWR_MOS_A at a high level, triggering the backup power supply switch. The fifteenth MOSFET Q15 and the sixteenth MOSFET Q16 are cut off due to the high PWR_MOS_A level, cutting off the +5V main power supply path and preventing reverse current loss from the 298th capacitor C298. The C_DISCHARGE signal remains high, and the NAND gate control unit U38 outputs PWR_MOS_B at a low level, turning on the seventeenth MOSFET Q17 and the eighteenth MOSFET Q18. Simultaneously, the boost subunit U35 starts, boosting the low-voltage energy (e.g., 4.8V) stored in the 298th capacitor C298 to 5V (BOOST_5V), continuously supplying power to the system through the seventeenth MOSFET Q17 and the eighteenth MOSFET Q18, ensuring critical operations such as data preservation.

[0033] After the system completes data saving, the control signal C_DISCHARGE is pulled low, triggering an active power-off process: the enable terminal (EN) of the boost subunit U35 is disabled, the DC boost unit 32 stops working, and no longer boosts the power of the 298th capacitor C298. The low level of C_DISCHARGE causes the NAND gate control unit U38 to output PWR_MOS_B at a high level, and the 17th MOSFET Q17 and the 18th MOSFET Q18 are turned off, completely cutting off the power supply path from the 298th capacitor C298 to the system, avoiding unnecessary power consumption.

[0034] In this way, by coordinating the power conversion module 1, the system power failure detection module 2, the power supply capacitor charging and discharging unit 31, the DC boost unit 32, the first control unit 33, the second control unit 34, and the logic control unit 35, this application ensures that when the initial power supply suddenly fails, the power supply capacitor in the power supply capacitor charging and discharging unit 31 will discharge and supply power to the system through the DC boost unit 32. However, after the initial power supply fails, the first control unit 33 immediately shuts down, thus preventing the DC boost unit 32 from boosting the voltage to 5V and then continuing to charge the power supply capacitor through the current-limiting resistor. Simultaneously, the energy stored in the power supply capacitor is only used to meet the system's power failure preservation needs; after the system completes the preservation operation, almost no additional energy consumption occurs. Since energy remains in the power supply capacitor after the power failure preservation process ends, the current in the current-limiting resistor will not be excessive when the initial power supply is frequently switched on and off, thereby reducing losses and effectively reducing the risk of the current-limiting resistor and the power supply capacitor burning out.

[0035] In one embodiment, the power switching module 3 further includes a step-down unit 36 ​​for providing a 3.3V power supply voltage to the system.

[0036] The step-down unit 36 ​​includes a step-down subunit U34, a sixteenth inductor L16, a two hundred and eighty-fourth resistor R284, a two hundred and eighty-ninth resistor R289, a three hundred and thirty-second resistor R332, a light-emitting diode D55, a two hundred and ninety-first capacitor C290, a two hundred and ninety-first capacitor C291, a two hundred and ninety-second capacitor C292, a two hundred and ninety-third capacitor C293, a two hundred and ninety-fourth capacitor C294, a two hundred and ninety-fifth capacitor C295, a two hundred and ninety-sixth capacitor C296, and capacitors C291, C292, and C293 connected in parallel, with one end connected to the VIN lead of the step-down subunit U34. The pin connections are as follows: one end of capacitor C290 (number 290) is connected to the BST pin of step-down subunit U34, and the other end is connected to one end of inductor L16 (number 16). The other end of inductor L16 is connected to one end of capacitors C294 (number 294), C295 (number 295), C296 (number 296), and R284 (number 284). The other end of resistor R284 is connected to one end of resistor R289 (number 289). The other end of resistor R289 is connected to ground. One end of resistor R332 (number 332) is connected to VCC_3V3, and the other end is connected to LED D55.

[0037] The step-down subunit U34 converts the main 5V or BOOST_5V to 3.3V, providing a stable 3.3V power supply for system logic circuits (such as MCUs, sensors, etc.). Resistor R332 is the current-limiting resistor for the LED D55, limiting the operating current of the indicator light and preventing damage from overcurrent. LED D55: Works with resistor R332 (332nd resistor) as a power indicator for VCC_3V3. When lit, it indicates that the 3.3V power supply is normal, providing visualization of the circuit status. Inductor L16 (16th inductor): The energy storage element of buck unit 36. Under the internal switching control of buck subunit U34, it achieves a 5V to 3.3V step-down conversion, providing a stable 3.3V power output. Capacitors C290 (290th), C291 (291st), C292 (292nd), C293 (293rd), C294 (294th), C295 (295th), and C296 (296th) are used to filter out the ripple of the buck subunit U34 circuit, ensuring a stable power supply voltage.

[0038] like Figure 3As shown, in one embodiment, the system power failure detection module 2 includes a voltage divider and isolation unit 21, a signal driving unit 22, and a voltage regulator unit 23. The input terminal of the voltage divider and isolation unit 21 is connected to the initial power supply, and the output terminal is connected to the input terminal of the signal driving unit. It is used to divide the initial power supply and isolate the high-voltage side and the low-voltage side. The signal driving unit 22 converts the voltage value output by the voltage divider and isolation unit 21 into a preset voltage value and outputs a stable control signal. The input terminal of the voltage regulator unit 23 is connected to the initial power supply, and the output terminal is connected to the input terminal of the signal driving unit 22. It is used to divide the initial power supply and filter out noise.

[0039] The voltage divider and isolation unit 21 includes an optocoupler U31, a 263rd resistor R263, a 265th resistor R265, a 268th resistor R268, a 270th resistor R270, and a 30th diode D30. One end of the 263rd resistor R263, the 265th resistor R265, and the 270th resistor R270 is connected to +24VB. The other end of the 263rd resistor R263 and the 265th resistor R265 is connected to the 268th resistor R268, one end of the optocoupler U31, and the negative terminal of the 30th diode D30, respectively. The other end of the 270th resistor R270 is connected to the 268th resistor R268, one end of the optocoupler U31, and the positive terminal of the 30th diode D30, respectively.

[0040] The signal driving unit 22 includes an eleventh field-effect transistor Q11, a twelfth field-effect transistor Q12, a 260th resistor R260, a 261st resistor R261, a 267th resistor R267, and a 289th capacitor C289. One end of the 267th resistor R267 is connected to VCC_3V3, and the other end of the 267th resistor R267 is connected to one end of the 289th capacitor C289 and the gate of the eleventh field-effect transistor Q11. The drain of the eleventh field-effect transistor Q11 is connected to one end of the 260th resistor R260 and the gate of the twelfth field-effect transistor Q12. The other end of the 260th resistor R260 is connected to VCC_5V. The drain of the twelfth field-effect transistor Q12 is connected to one end of the 261st resistor R261, and the other end of the 261st resistor R261 is connected to VCC_5V.

[0041] The voltage regulator unit 23 includes a first voltage regulator U32, a second voltage regulator U33, a second 74 resistor R274, a second 75 resistor R275, a second 76 resistor R276, a second 77 resistor R277, a fifth 90 capacitor C590, and a fifth 91 capacitor C591. One end of the second 74 resistor R274 is connected to +24VB. The other end of the second 74 resistor R274 is connected to one end of the second 76 resistor R276 and one end of the fifth 90 capacitor C590, as well as the second pin of the first voltage regulator U32. The first pin of the first voltage regulator U32 is connected to one end of the second 75 resistor R275, the second 77 resistor R277, one end of the fifth 91 capacitor C591, and the second pin of the second voltage regulator U33.

[0042] Resistors R263 (263rd) and R265 (265th) are connected in parallel at the +24VB input terminal to filter out high-frequency ripple in the power supply and stabilize the input voltage. Resistors R274 (274th), R276 (276th), and C590 (590th) form an RC filter circuit to further filter out noise in +24VB. The first Zener diode U32 regulates the +24VB voltage to prevent overvoltage damage to subsequent circuits. Resistors R275 (275th), R277 (277th), and C591 (591st) form a voltage divider and filter circuit. Resistors R275 (275th) and R277 (277th) regulate the +24VB voltage. A 24VB voltage divider is used, with capacitor C591 (591st) filtering out ripple in the voltage divider signal. The second Zener diode, U33, regulates the voltage divider signal, ensuring the accuracy of subsequent detection stages. Resistors R268 (268th), R270 (270th), and diode D30 (30th) are used: R268 and R270 divide the +24VB voltage, while diode D30 clamps overvoltage signals to prevent damage to optocoupler U31 due to excessive voltage. Optocoupler U31 provides electrical isolation between the "high voltage side (+24VB)" and the "low voltage side (3.3V / 5V control circuit)," preventing high-voltage interference from affecting the control logic. Resistor R267 pulls up the SYS_PWR_1 signal, ensuring it remains stable at a high level when the optocoupler is off. Capacitor C289 (289th) is used for filtering to suppress signal noise. The eleventh field-effect transistor Q11 and the twelfth field-effect transistor Q12 are N-channel MOSFETs: they convert the 3.3V level of SYS_PWR_1 to a 5V PWR_MOS_A signal, achieving level matching and signal driving; the 260th resistor R260 and the 261st resistor R261: pull up the drains of the eleventh field-effect transistor Q11 and the twelfth field-effect transistor Q12 respectively, ensuring the level stability of the PWR_MOS_A signal when the eleventh field-effect transistor Q11 and the twelfth field-effect transistor Q12 are turned off.

[0043] The core function of the system power failure detection module 2 is to monitor the +24VB power supply status in real time and output the PWR_MOS_A control signal to trigger subsequent power switching actions.

[0044] When the +24VB power supply is normal: the voltage output by the voltage divider circuit does not trigger the thirtieth diode D30 and the second Zener diode U33, the LED of the optocoupler U31 has no current, the phototransistor is cut off, SYS_PWR_1 is pulled up to a high level by VCC_3V3, the eleventh field-effect transistor Q11 and the twelfth field-effect transistor Q12 are turned on, and PWR_MOS_A outputs a high level, indicating that the +24VB power supply is normal.

[0045] When the +24VB power supply is powered off / overvoltageed: When powered off, there is no input voltage to +24VB; when overvoltageed, the thirtieth diode D30 breaks down, the second Zener diode U33 is triggered, the LED of the optocoupler U31 conducts and emits light, the phototransistor conducts, and SYS_PWR_1 is pulled low.

[0046] In this way, the system power failure detection module 2 converts the +24VB power state into a PWR_MOS_A level signal, providing a precise trigger basis for the subsequent power switching circuit, ensuring that the system can switch to the backup power supply in a timely manner when the main power supply is abnormal.

[0047] like Figure 5 As shown, in one embodiment, the power management circuit further includes an external drive power module 4, which includes an external drive power unit 41 and an isolated communication power unit 42. The input terminal of the external drive power unit 41 is connected to the power conversion module 1, and the output terminal is connected to the isolated communication power unit 42.

[0048] The external drive power supply unit 41 includes a step-down subunit U28, which is a DC-DC step-down chip that converts the input COM+ voltage to VCC_12V.

[0049] The isolated communication power supply unit 42 includes a linear voltage regulator subunit U29, which is a linear voltage regulator chip that steps down VCC_12V to 5V.

[0050] like Figure 2 As shown, in one embodiment, the power conversion module 1 includes a first power conversion unit 11 and a second power conversion unit 12. The input terminal of the first power conversion unit 11 is connected to the input terminal of the external drive power module 4, and the output terminal is connected to the input terminal of the second power conversion unit 12. The output terminal of the second power conversion unit 12 is connected to the input terminal of the power switching module 3.

[0051] The external 24V input is via P9, and after being processed by the 53rd diode D53 for reverse connection protection and the LC filter circuit (7th inductor L7, 6th inductor L6), it outputs clean +24VC, +24VB, and +24VA power to meet the needs of different 24V loads. The +24VB is stepped down by the buck converter U82 and stored in the 8th inductor L8, outputting a stable +5V to power the internal circuitry of the system. The +5V is output as VUSB_5V via the power electronic switch U30, which prevents output short circuits and external current backflow. The PE port on the P9 product is the interface for grounding the product.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A power management circuit, characterized by: The application relates to a power supply switching module. The power supply switching module comprises a power supply conversion module, a system power supply outage detection module and a power supply switching module. The power supply conversion module is used for generating a preset voltage value according to a preset initial power supply and supplying power to the power supply switching module. The system power supply outage detection module is used for detecting an initial power supply state and outputting a corresponding control signal to the power supply switching module. The power supply switching module comprises a power supply capacitor charging and discharging unit, a direct current voltage boosting unit, a first control unit, a second control unit and a logic control unit. The input end of the first control unit is connected with the output end of the power supply conversion module, and the first control unit is used for controlling the on-off of the power supply conversion module and a system; the power supply capacitor charging and discharging unit is used for obtaining the preset voltage value output by the power supply conversion module and charging a power supply capacitor; after the initial power supply is powered off, the system is sequentially supplied with power through the direct current voltage boosting unit and the second control unit; the direct current voltage boosting unit is used for boosting the voltage output by the power supply capacitor and supplying power to the system after the initial power supply is powered off; and the logic control unit controls the on-off of the second control unit according to a preset input signal.

2. The power management circuit of claim 1, wherein: The power supply switching module further comprises a voltage reducing unit used for providing 3.3V power supply voltage for the system.

3. The power management circuit of claim 1, wherein: The power supply capacitor charging and discharging unit comprises a second 298 capacitor, a second 285 resistor, a second 287 resistor and a fourth 48 diode; one end of the second 298 capacitor is connected with the negative electrode of the fourth 48 diode, the other end is connected with the ground electrode, the positive electrode of the fourth 48 diode is connected with one end of the second 285 resistor and the second 287 resistor respectively, and the other ends of the second 285 resistor and the second 287 resistor are connected with a 5V power supply.

4. The power management circuit of claim 3, wherein: The direct current voltage boosting unit comprises a seventeenth inductor, a fourth 46 diode, a second 299 capacitor and a voltage boosting subunit; one end of the seventeenth inductor is connected with one end of the second 298 capacitor, the other end is connected with the positive electrode of the fourth 46 diode and the first pin of the voltage boosting subunit, and the negative electrode of the fourth 46 diode is connected with one end of the second 299 capacitor.

5. The power management circuit of claim 4, wherein: The first control unit comprises a fifteenth MOS tube, a sixteenth MOS tube and a second 282 resistor; the source electrodes of the fifteenth MOS tube and the sixteenth MOS tube are connected with a 5V power supply, the drain electrodes are connected with a VCC_5V power supply, the gate electrodes are connected with one end of the second 282 resistor, and the other end of the second 282 resistor is connected with the output end of the system power supply outage detection module.

6. The power management circuit of claim 5, wherein: The second control unit comprises a seventeenth MOS tube, an eighteenth MOS tube and a second 296 resistor; the source electrodes of the seventeenth MOS tube and the eighteenth MOS tube are connected with a VCC_5V power supply, the drain electrodes are connected with one end of the second 299 capacitor, the gate electrodes are connected with one end of the second 296 resistor, and the other end of the second 296 resistor is connected with the output end of the logic control unit.

7. The power management circuit of claim 6, wherein, The logic control unit comprises an AND NOT gate control unit; the input end of the AND NOT gate control unit is connected with the output end of the system power supply outage detection module, and the output end is connected with the other end of the second 296 resistor.

8. The power management circuit of claim 1, wherein The system power supply power failure detection module includes a voltage dividing and isolating unit, a signal driving unit and a voltage stabilizing unit. The input end of the voltage dividing and isolating unit is connected with an initial power supply, and the output end is connected with the input end of the signal driving unit, for dividing the voltage of the initial power supply and isolating the strong and weak electric sides. The signal driving unit converts the voltage value output by the voltage dividing and isolating unit into a preset voltage value and outputs a stable control signal. The input end of the voltage stabilizing unit is connected with the initial power supply, and the output end is connected with the input end of the signal driving unit, for dividing the voltage of the initial power supply and filtering out noise.

9. The power management circuit of claim 8, wherein, The voltage dividing and isolating unit includes a photoelectric coupler, a second 263 resistor, a second 265 resistor, a second 268 resistor, a second 270 resistor and a third 32 diode. One end of the second 263 resistor, the second 265 resistor and the second 270 resistor is connected with +24VB. The other end of the second 263 resistor and the second 265 resistor is connected with the second 268 resistor and the photoelectric coupler and the negative electrode of the third 32 diode, respectively. The other end of the second 270 resistor is connected with the second 268 resistor and the photoelectric coupler and the positive electrode of the third 32 diode, respectively.

10. The power management circuit of claim 9, wherein, The signal driving unit includes an eleventh field effect tube, a twelfth field effect tube, a second 260 resistor, a second 261 resistor, a second 267 resistor and a second 289 capacitor. One end of the second 267 resistor is connected with VCC_3V3. The other end of the second 267 resistor is connected with one end of the second 289 capacitor and the gate of the eleventh field effect tube, respectively. The drain of the eleventh field effect tube is connected with one end of the second 260 resistor and the gate of the twelfth field effect tube, respectively. The other end of the second 260 resistor is connected with VCC_5V. The drain of the twelfth field effect tube is connected with one end of the second 261 resistor. The other end of the second 261 resistor is connected with VCC_5V.

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