A DC power management device based on autonomous switching of lithium batteries

Abstract

The present invention provides a DC power management device based on autonomous lithium battery switching. The device has two power inputs, one of which is a switching power input directly used to power the DC power device; the other is a backup power input. When the switching power input is abnormal, a controller automatically switches to the backup power supply, and the backup power supply supplies power to the DC power device through a boost circuit. The device includes a power signal processing circuit, a charging management circuit, a boost circuit, a buck circuit, a comparator, a current sensing amplifier, a sampling resistor, an optocoupler, a transistor, a P-MOS transistor, and a controller. It can realize bidirectional uninterrupted power supply between the switching power supply and the backup power supply. The comparator monitors the status of the switching power supply. When it is abnormal, the power status IO outputs a high level. The transistor, optocoupler isolator, and P-MOS transistor are used to control the backup power supply through the boost circuit to achieve autonomous dual power switching.

Description

Technical Field

[0001] The present invention belongs to the technical field of system automation control, and in particular relates to a direct current power management device based on autonomous switching of lithium batteries. Background Art

[0002] With the development of industrial automation control and production safety, sensors are installed in factories to monitor the environment of on-site process equipment and special environments to ensure the normal operation of the production environment. To ensure the normal operation of the sensors, it is necessary to ensure that the power supply of the system is normal. When the mains power is abnormally disconnected on site, the normal operation of the sensors and related linkages will not be affected, ensuring the continuity of monitoring operations. For electrical equipment that can cause significant economic losses or even safety accidents after the power supply system is interrupted, a common solution to improve power supply reliability is to add an uninterruptible power supply (UPS) between the electrical equipment and the power supply. However, this solution has disadvantages such as low conversion efficiency, large size, high cost, and long switching time. It is generally not suitable for general sensors or small system monitoring, and equipment operating on a DC24V power supply. Summary of the Invention

[0003] Based on the above problems, the present invention provides a DC power management device based on autonomous switching of lithium batteries, including two power inputs to supply power to DC power-consuming equipment, one of which is a switching power input, which is directly used to power DC power-consuming equipment; the other is a backup power input. When the switching power input is abnormal, the controller automatically switches to the backup power supply, and the backup power supply supplies power to the DC power-consuming equipment through a boost circuit.

[0004] The DC power management device includes: a power signal processing circuit, a charging management circuit, a boost circuit, a buck circuit, a comparator, a current sensing amplifier, a sampling resistor, a first photocoupler, a second photocoupler, a first transistor, a second transistor, a P-MOS tube, and a controller; a group of normally open contacts of the switch button are connected to the input end of the power signal processing circuit on one side and to the negative end of the comparator after voltage division by a resistor on the other side; the output end of the power signal processing circuit is connected to the input end of the buck circuit on one side, to the DC power device on the other side, and to the charging management circuit on the other side; the buck circuit outputs two different DC level signals for providing different power supply voltages; the output end of the comparator is connected to the negative electrode of the first photocoupler, the collector of the first photocoupler The output end of the charging management circuit is connected to the backup power supply, the backup power supply is connected to one end of the sampling resistor, the other end of the sampling resistor is connected to the source of the P-MOS tube, the drain of the P-MOS tube is connected to the input end of the boost circuit, the output end of the boost circuit is connected to the DC power device, the gate of the P-MOS tube is connected to the collector of the second photocoupler, the cathode of the second photocoupler is connected to the collector of the first transistor, the base of the first transistor is connected to the cathode of the first photocoupler, the collector of the second transistor is connected to the base of the first transistor, and the base of the second transistor is connected to the output end of the controller; the input end of the current sensing amplifier is respectively connected to the two ends of the resistor, and the output end of the current sensing amplifier is connected to the controller through a serial bus.

[0005] A set of normally closed contacts of the switch button is connected to the input end of the controller for determining whether the button action is executed; a set of normally open contacts is connected to the switch power supply for controlling the switch power supply to be turned on and off.

[0006] The step-down circuit outputs a two-stage step-down voltage, the primary output end of the step-down circuit is respectively connected to the positive end of the comparator, the positive electrode of the first photoelectric coupler, and the positive electrode of the second photoelectric coupler, and the secondary output end of the step-down circuit is respectively connected to one end of the switch button, the power supply port of the controller, and the collector of the first photoelectric coupler;

[0007] The power signal processing circuit is used to perform current limiting protection, shaping, coupling, filtering on the input power signal in sequence, and then output it to power the device and charge the backup power supply;

[0008] The charging management circuit is used for constant current charging and has over-temperature protection, overcharge protection, and charging status indication functions;

[0009] The boost circuit is used to boost the backup power supply to a DC 24V output to meet the user's power supply needs;

[0010] The step-down circuit is used to achieve two-stage voltage reduction, outputting DC 5V and DC 3.3V supply voltages respectively.

[0011] The current sensing amplifier is INA219, and the backup power supply is a lithium battery module. When INA219 detects that the current voltage value of the lithium battery module is lower than the minimum discharge voltage value, the controller controls the second transistor to cut off.

[0012] The automatic switching of the backup power supply by the controller is specifically described as follows: when the switching power supply is abnormal, the positive end of the comparator is greater than the negative end, the switching power supply state is high, the controller input end detects a high level, the controller output end outputs a low level, the P-MOS tube is in the on state, the backup power supply output is started, and the backup power supply is supplied to the DC power equipment via the boost circuit.

[0013] The beneficial effects of the present invention are:

[0014] The present invention realizes the uninterrupted power supply function of DC power-consuming equipment by monitoring the switching power supply and the backup power supply (lithium battery module) through the controller. When the power supply of the user equipment is abnormal, it can instantly switch the power supply mode between the switching power supply and the backup power supply to ensure the uninterrupted power supply of the equipment. In addition, the user can realize remote backup power supply switching and power monitoring functions through the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the DC power management device based on autonomous switching of lithium batteries in the present invention.

[0016] Figure 2 This is a schematic diagram of the power signal processing circuit in the present invention.

[0017] Figure 3 This is a schematic diagram of the charging management circuit in the present invention.

[0018] Figure 4 Schematic diagram of the boost circuit in the present invention.

[0019] Figure 5 Schematic diagram of the step-down circuit in the present invention. DETAILED DESCRIPTION

[0020] The invention will be further described below with reference to the accompanying drawings and specific implementation examples.

[0021] The present invention provides a lithium battery-based, autonomously switching DC power management device. The device utilizes two power inputs to supply DC power to DC devices: a switching power supply, which serves as the primary power input; and a backup power supply. If the switching power input experiences an abnormality, the device automatically switches to the backup power supply, providing 24V DC power to the DC devices via a boost circuit. The device incorporates a built-in MCU control unit, which monitors I / O status to enable abnormal switching power status monitoring, remote backup power supply control, and backup power level monitoring.

[0022] like Figure 1 As shown, the DC power management device includes: a power signal processing circuit, a charging management circuit, a boost circuit, a buck circuit, a comparator, a current sensing amplifier, a sampling resistor, a first photocoupler, a second photocoupler, a first transistor, a second transistor, a P-MOS tube, and a controller; a group of normally open contacts of the switch button are connected to the input end of the power signal processing circuit on one side and to the negative end of the comparator after voltage division through a resistor; the output end of the power signal processing circuit is connected to the input end of the buck circuit on one side, to the DC power device on one side, and to the charging management circuit on the other side; a group of normally closed contacts of the switch button are connected to the input end of the controller; the buck circuit outputs two different DC level signals for providing different power supply voltages; the output end of the comparator is connected to the negative end of the first photocoupler The collector of the first photocoupler is connected to the input end of the controller; the output end of the charging management circuit is connected to the backup power supply, the backup power supply is connected to one end of the sampling resistor, the other end of the sampling resistor is connected to the source of the P-MOS tube, the drain of the P-MOS tube is connected to the input end of the boost circuit, the output end of the boost circuit is connected to the DC power device, the gate of the P-MOS tube is connected to the collector of the second photocoupler, the cathode of the second photocoupler is connected to the collector of the first transistor, the base of the first transistor is connected to the cathode of the first photocoupler, the collector of the second transistor is connected to the base of the first transistor, and the base of the second transistor is connected to the output end of the controller; the input ends of the current sensing amplifier are respectively connected to the two ends of the resistor, and the output end of the current sensing amplifier is connected to the controller through a serial bus.

[0023] The step-down circuit outputs a two-stage step-down voltage, the primary output end of the step-down circuit is respectively connected to the positive end of the comparator, the positive electrode of the first photoelectric coupler, and the positive electrode of the second photoelectric coupler, and the secondary output end of the step-down circuit is respectively connected to one end of the switch button, the power supply port of the controller, and the collector of the first photoelectric coupler;

[0024] The controller automatically switches between dual power supplies, which can be specifically described as follows: when the switching power supply is normal, the positive end of the comparator is less than the negative end, the switching power supply state is low, one signal controls the first optocoupler isolator to turn on, the controller monitoring state IO is low, and another signal controls the second optocoupler isolator to turn off through the first transistor, the P-MOS tube is in the cut-off state, the controller outputs the backup power remote control interface as low, and the DC power consumption equipment is powered by the switching power supply; when the switching power supply is abnormal, the positive end of the comparator is greater than the negative end, the switching power supply state is high, one signal controls the first optocoupler isolator to turn off, the controller monitoring state IO is high, another signal controls the second optocoupler isolator to turn on through the first transistor, the P-MOS tube is in the on state, the backup power output is started, the controller's backup power remote control IO interface output is low, and the DC power consumption equipment is powered by the backup power supply through the boost circuit. When the switching power supply recovers from abnormality to normal, the negative end of the comparator is greater than the positive end, the switching power supply state changes from high level to low level, one signal controls the first optocoupler isolator to turn on, the controller monitoring state IO is low level, and the other signal controls the second optocoupler isolator to turn off through the first transistor, the P-MOS tube changes to the cut-off state, the backup power output is turned off, the controller's backup power remote control IO interface output is low level, and the DC power equipment is powered by the switching power supply.

[0025] The on / off button controls the power supply and provides feedback. When the operator presses the on / off button to power off, the controller monitors the normally closed signal state of the on / off button, indicating it is low. The controller MCU assumes that the device is disconnecting normally, and the backup power supply remote control IO outputs high, disconnecting the backup power supply. If the operator does not press the on / off button to power off, the controller monitors the normally closed signal state of the on / off button, indicating it is high. The MCU assumes that the device is disconnecting abnormally, and the backup power supply remote control IO outputs low, maintaining backup power supply to the device.

[0026] When the backup power supply is started, the controller monitors the voltage and current status of the backup power supply through a 0.1R sampling resistor and a current sensing amplifier INA219.

[0027] The power signal processing circuit is used to perform current limiting protection, shaping, coupling, filtering on the power signal in sequence, and then output it to power the device and charge the backup power supply. This circuit uses a resettable fuse to achieve current limiting protection, a common-mode inductor and a bypass capacitor to achieve coupling, and a π-type filtering circuit through a combination of inductors and capacitors to optimize the output power signal. The specific circuit diagram is shown in FIG. Figure 2 shown.

[0028] The CN3704 chip used in the charging management circuit can realize constant current charging of lithium batteries, and has over-temperature protection, overcharge protection, and charging status indication functions. The charging current of the lithium battery is 2A. This circuit design is based on the CN3704 user manual. The charging current limit is realized by the R7 circuit, and the charging management status indication is realized by the green and red indicator lights. The specific circuit diagram is as follows Figure 3 shown.

[0029] The boost circuit uses the XL6019 chip, which can boost the backup power supply to DC24V to meet the user's power supply needs. This circuit mainly achieves a DC 24V output by matching the resistance values ​​of R32 and R33. The specific circuit diagram is as follows: Figure 4 shown.

[0030] The step-down circuit uses XL1509_5.0E1 and XL1509_3.3E1, which can realize DC5V and DC3.3V voltage output in the device and provide power supply voltage; the chip selected in this circuit is constant voltage output, and the required voltage can be output directly by powering. The specific circuit diagram is as follows Figure 5 shown.

[0031] The device provided by the present invention can achieve bidirectional uninterruptible power supply functions for the system power supply and the backup power supply. When the switching power supply is abnormally powered off, the output level status of the switching power supply is monitored through the LM393 comparator. When abnormal power supply occurs, the power supply status IO outputs a high level. The backup power supply is controlled by a transistor and an optocoupler isolator through a boost circuit to achieve autonomous dual power switching. The automatic power switching response time is within 100μs. When the switching power supply is normally powered off, the backup power supply can also be remotely controlled to output a high level through the IO, realizing backup power supply signal output control and stopping the backup power supply. The controller uses the INA219 chip (operational amplifier) ​​and sampling resistor to monitor the voltage and current of the backup power supply, and monitor the discharge status of the backup power supply in real time. When the backup power supply discharge falls below the minimum discharge value, the backup power supply remotely controls the IO output to output a high level, causing the backup power supply to stop supplying.

Claims

1. A DC power management device based on autonomous switching of lithium batteries, characterized in that: It includes two power inputs to supply power to DC power devices. One of them is the switching power input, which is directly used to power DC power devices; the other is the backup power input. When the switching power input is abnormal, the controller automatically switches to the backup power supply, and the backup power supply supplies power to the DC power devices through the boost circuit. A DC power management device based on autonomous switching of lithium batteries, characterized by comprising: A power signal processing circuit, a charging management circuit, a boost circuit, a buck circuit, a comparator, a current sensing amplifier, a sampling resistor, a first photocoupler, a second photocoupler, a first transistor, a second transistor, a P-MOS transistor, and a controller; a set of normally open contacts of the switch button are connected one way to the input end of the power signal processing circuit and one way to the negative end of the comparator after voltage division through a resistor; the output end of the power signal processing circuit is connected one way to the input end of the buck circuit, one way to the DC power device, and one way to the charging management circuit; the buck circuit outputs two different DC level signals for providing different power supply voltages; the output end of the comparator is connected to the negative terminal of the first photocoupler, and the collector of the first photocoupler is connected to the input end of the controller; The output end of the charging management circuit is connected to a backup power supply, which is connected to one end of a sampling resistor, the other end of the sampling resistor is connected to the source of a P-MOS tube, the drain of the P-MOS tube is connected to the input end of a boost circuit, the output end of the boost circuit is connected to a DC power consumer, the gate of the P-MOS tube is connected to the collector of a second photocoupler, the negative electrode of the second photocoupler is connected to the collector of a first transistor, the base of the first transistor is connected to the negative electrode of the first photocoupler, the collector of the second transistor is connected to the base of the first transistor and the output end of a comparator, and the base of the second transistor is connected to the output end of a controller; the input end of a current sensing amplifier is respectively connected to both ends of the sampling resistor, and the output end of the current sensing amplifier is connected to the controller via a serial bus; A set of normally closed contacts of the switch button is connected to the input end of the controller to determine whether the button action is executed; a set of normally open contacts is connected to the switch power supply to control the switch power supply to be turned on and off; The step-down circuit outputs a two-stage step-down voltage, the primary output end of the step-down circuit is respectively connected to the positive end of the comparator, the positive electrode of the first photoelectric coupler, and the positive electrode of the second photoelectric coupler, and the secondary output end of the step-down circuit is respectively connected to one end of the switch button, the power supply port of the controller, and the collector of the first photoelectric coupler; The automatic switching of the backup power supply by the controller is specifically described as follows: when the switching power supply is abnormal, the positive end of the comparator is greater than the negative end, the switching power supply state is high, the controller input end detects a high level, the controller output end outputs a low level, the P-MOS tube is in the on state, the backup power supply output is started, and the backup power supply is supplied to the DC power equipment via the boost circuit.

2. A DC power management device based on autonomous switching of lithium batteries according to claim 1, characterized in that: The power signal processing circuit is used to perform current limiting protection, shaping, coupling, filtering on the input power signal in sequence, and then output it to power the device and charge the backup power supply; The charging management circuit is used for constant current charging and has over-temperature protection, overcharge protection, and charging status indication functions; The boost circuit is used to boost the backup power supply to a DC 24V output to meet the user's power supply needs; The step-down circuit is used to achieve two-stage voltage reduction, outputting DC 5V and DC 3.3V supply voltages respectively.

3. A DC power management device based on autonomous switching of lithium batteries according to claim 1, characterized in that: The current sensing amplifier is INA219, and the backup power supply is a lithium battery module. When INA219 detects that the current voltage value of the lithium battery module is lower than the minimum discharge voltage value, the controller controls the second transistor to cut off.

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