Dual power input seamless switching power supply circuit and circuit control method

Abstract

The present application relates to a kind of double power input seamless switching power supply circuit and circuit control method, belong to circuit technical field, double power input seamless switching power supply circuit provided by the present application, by setting first threshold voltage and second threshold voltage, when first DC voltage is higher than second threshold voltage, output second control signal, step-down module is in standby state, does not consume additional power, and first DC voltage is output to load, when first DC voltage is lower than first threshold voltage, output first control signal, step-down module immediately intervenes work and is reduced to second DC voltage as DC high voltage, and second DC voltage is output to load, output voltage is not obvious drop in switching process, realize the seamless switching of true, guarantee uninterrupted power supply, by setting double threshold voltage, improve control precision, avoid the repeated switching problem caused by input voltage near critical point fluctuation, improve switching stability.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, and in particular to a dual-power input seamless switching power supply circuit and circuit control method. Background Technology

[0002] In fields such as industrial control, communication equipment, medical electronics, and security monitoring, electrical equipment typically requires uninterrupted power supply capabilities to prevent equipment downtime, data loss, or even system crashes due to abnormal power outages. To achieve this goal, existing technologies generally employ dual-power redundant supply schemes, which involve setting up a switching device between the main power supply and the backup power supply. When the main power supply fails or experiences a voltage drop, the system automatically switches to the backup power supply to continue powering the load.

[0003] Existing technologies have the following shortcomings: high switching losses, with severe conduction losses in diode-based solutions and lifespan and reliability issues with mechanical contacts in relay-based solutions; interrupted switching, with millisecond-level delays in mechanical relay switching, making true "seamless" switching impossible and potentially causing load voltage drops; and low control precision, with most solutions using a single voltage threshold for switching judgment, which may trigger frequent switching when the main power supply voltage fluctuates around the threshold, affecting system stability. Summary of the Invention

[0004] In view of this, it is necessary to provide a dual-power input seamless switching power supply circuit and circuit control method to solve the problems of large switching losses, interrupted switching, and low control accuracy in existing dual-power switching schemes.

[0005] To address the aforementioned problems, in a first aspect, the present invention provides a dual-power input seamless switching power supply circuit, comprising: The system includes a first power input terminal, a second power input terminal, a rectifier and filter module, a step-down module, a comparator module, and a top-output module. The first power input terminal is connected to the comparison module and the top output module respectively; The second power input terminal, the rectifier and filter module, the step-down module, and the top output module are connected in sequence; The enable control terminal of the buck module is connected to the comparator module; The first power input terminal is used to receive the first DC voltage; The second power input terminal is used to receive AC voltage; The rectifier and filter module is used to convert the AC voltage into a DC high voltage. The comparison module is configured to output a first control signal when the first DC voltage is lower than a first threshold voltage, and to output a second control signal when the first DC voltage is higher than a second threshold voltage; wherein the second threshold voltage is higher than the first threshold voltage. The step-down module is used to step down the DC high voltage to a second DC voltage based on the first control signal, or to stop working based on the second control signal; The top output module is used to output the second DC voltage based on the first control signal, or to output the first DC voltage based on the second control signal.

[0006] In one possible implementation, the comparison module includes: Voltage divider sampling circuit, isolation amplifier gain circuit, reference voltage source and voltage comparator; The voltage divider sampling circuit is connected between the first power input terminal and the isolation amplification gain circuit; The isolation amplification gain circuit is connected to the inverting input terminal of the voltage comparator; The reference voltage source is connected to the non-inverting input of the voltage comparator via a first resistor; The output terminal of the voltage comparator is connected to the non-inverting input terminal of the voltage comparator through a second resistor.

[0007] In one possible implementation, the voltage divider sampling circuit is used to perform voltage divider sampling on the first DC voltage to obtain a sampled voltage. The isolation amplification gain circuit is used to amplify the sampled voltage; The reference voltage source is used to generate a compensation voltage; the compensation voltage is used to determine the first threshold voltage and the second threshold voltage. The voltage comparator is used to generate the first control signal when the amplified sampled voltage is higher than the first threshold voltage, and to generate the second control signal when the amplified sampled voltage is lower than the second threshold voltage.

[0008] In one possible implementation, the expression for the first threshold voltage is as follows: U z1 =U pull ×R2(R1+R2) Among them, U z1 U represents the first threshold voltage. pull R1 represents the compensation voltage, R2 represents the first resistor, and R2 represents the second resistor.

[0009] In one possible implementation, the expression for the second threshold voltage is as follows: U z2 =Upull ×R2(R1+R2)+5V×R1(R1+R2) Among them, U z2 U represents the second threshold voltage. pull R1 represents the compensation voltage, R2 represents the first resistor, and R2 represents the second resistor.

[0010] In one possible implementation, the top-output module includes: The first and second diodes are connected in parallel; The anode of the first diode is connected to the output terminal of the buck module; The anode of the second diode is connected to the first power input terminal; The cathodes of the first diode and the second diode are connected.

[0011] In one possible implementation, the first control signal is a high-level signal and the second control signal is a low-level signal.

[0012] In one possible implementation, the buck module includes a BUCK buck circuit.

[0013] In one possible implementation, the first DC voltage is 140V, the AC voltage is 220V, the DC high voltage is 310V, and the second DC voltage is 130V.

[0014] Secondly, the present invention also provides a circuit control method applied to the dual-power input seamless switching power supply circuit described in any of the above implementations, comprising: The system receives a first DC input voltage through the first power input terminal and an AC voltage through the second power input terminal, and converts the AC voltage into a DC high voltage. When the first DC voltage is lower than the first threshold voltage, a first control signal is output. Based on the first control signal, the step-down module is controlled to step down the high DC voltage to a second DC voltage and output the second DC voltage. When the first DC voltage is higher than the second threshold voltage, a second control signal is output. Based on the second control signal, the buck module is controlled to stop working and the first DC voltage is output; the second threshold voltage is higher than the first threshold voltage.

[0015] The beneficial effects of this invention are as follows: The dual-power input seamless switching power supply circuit and circuit control method provided by this invention, by setting a first threshold voltage and a second threshold voltage, outputs a second control signal when the first DC voltage is higher than the second threshold voltage, the buck module is in standby mode, does not consume additional power, and outputs the first DC voltage to the load. When the first DC voltage is lower than the first threshold voltage, it outputs a first control signal, the buck module immediately intervenes to step down the high DC voltage to the second DC voltage, and outputs the second DC voltage to the load. The output voltage does not drop significantly during the switching process, achieving true seamless switching and ensuring uninterrupted power supply to the load. By setting dual threshold voltages, the control accuracy is improved, avoiding repeated switching problems caused by fluctuations in the input voltage near the critical point, and improving switching stability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of an embodiment of the dual-power input seamless switching power supply circuit provided by the present invention; Figure 2 This is a schematic diagram of the structure of the comparison module provided by the present invention; Figure 3 This is a schematic diagram illustrating the hysteresis comparison effect provided by the present invention; Figure 4 This is a schematic diagram of the top-output module provided by the present invention; Figure 5 This is a schematic flowchart of an embodiment of the circuit control method provided by the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] In the description of the embodiments of the present invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0020] The terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] This invention provides a dual-power input seamless switching power supply circuit and circuit control method, which are described below.

[0023] Figure 1 A schematic diagram of an embodiment of the seamless switching power supply circuit with dual power inputs provided by the present invention is shown below. Figure 1 As shown, the dual-power input seamless switching power supply circuit includes: The system includes a first power input terminal 101, a second power input terminal 102, a rectifier and filter module 103, a step-down module 104, a comparator module 105, and a top-to-bottom output module 106. The first power input terminal 101 is connected to the comparison module 105 and the top output module 106 respectively; The second power input terminal 102, the rectifier and filter module 103, the step-down module 104 and the top output module 106 are connected in sequence; The enable control terminal of the step-down module 104 is connected to the comparator module 105; The first power input terminal 101 is used to receive a first DC voltage; The second power input terminal 102 is used to receive AC voltage; The rectifier and filter module 103 is used to convert the AC voltage into DC high voltage; The comparison module 105 is configured to output a first control signal when the first DC voltage is lower than a first threshold voltage, and to output a second control signal when the first DC voltage is higher than a second threshold voltage; wherein the second threshold voltage is higher than the first threshold voltage. The step-down module 104 is used to step down the DC high voltage to a second DC voltage based on the first control signal, or to stop working based on the second control signal; The top output module 106 is used to output the second DC voltage based on the first control signal or to output the first DC voltage based on the second control signal.

[0024] The first power input terminal (DC_Input) is used to receive a fixed DC input. The first DC voltage can be a DC voltage source with a nominal value of 140V.

[0025] The second power input terminal (AC_INput) is used to receive AC input. The AC voltage can be 220V AC mains power. This AC input is rectified and filtered to be converted into DC high voltage, and then stepped down by the step-down module.

[0026] The rectifier and filter module is connected between the AC power input terminal and the step-down module. It is used to convert the input AC voltage into a smooth DC voltage. The module includes a bridge rectifier circuit and a filter capacitor, and the output DC voltage is approximately 310V.

[0027] The comparison module monitors the voltage value at the first power input terminal in real time and compares it with a preset first threshold voltage and a second threshold voltage, outputting a switching control signal Buck_DRen. A first control signal is output when the first DC voltage is lower than the first threshold voltage, and a second control signal is output when the first DC voltage is higher than the second threshold voltage. The second threshold voltage is higher than the first threshold voltage to form a hysteresis control window.

[0028] By setting dual threshold voltages, the problem of repeated switching caused by fluctuations in input voltage near the critical point is avoided, thus improving switching stability.

[0029] The buck module can be a BUCK buck circuit that receives the high-voltage DC output from the rectifier and filter module and steps it down to a second DC voltage, such as 130V, using PWM control. The buck module can include basic components such as a power switch, a freewheeling diode, an energy storage inductor, and an output filter capacitor. The buck module's enable signal is output when the DC input (DC_INput) is lower than a first threshold voltage (i.e., the comparator module outputs the first control signal).

[0030] When the DC input is normal, the buck module is in standby mode and does not consume extra power. When the DC input drops to the first threshold voltage, the buck module immediately starts working. The output voltage does not drop significantly during the switching process, achieving true seamless switching and ensuring uninterrupted power supply to the load.

[0031] The top output module consists of a two-phase rectifier bridge, which outputs the larger input voltage and prevents the two input voltages from affecting each other. Based on the first control signal or the second control signal, it automatically and selectively outputs the first DC voltage or the second DC voltage to the load.

[0032] In summary, the dual-power input seamless switching power supply circuit provided in this embodiment of the invention, by setting a first threshold voltage and a second threshold voltage, outputs a second control signal when the first DC voltage is higher than the second threshold voltage, and the buck module is in standby mode, consuming no additional power, and outputs the first DC voltage to the load. When the first DC voltage is lower than the first threshold voltage, it outputs a first control signal, and the buck module immediately intervenes to step down the high DC voltage to the second DC voltage, and outputs the second DC voltage to the load. The output voltage does not drop significantly during the switching process, achieving true seamless switching and ensuring uninterrupted power supply to the load. By setting dual threshold voltages, the control accuracy is improved, avoiding repeated switching problems caused by fluctuations in the input voltage near the critical point, and improving switching stability.

[0033] In some embodiments of the present invention, the comparison module includes: Voltage divider sampling circuit, isolation amplifier gain circuit, reference voltage source and voltage comparator; The voltage divider sampling circuit is connected between the first power input terminal and the isolation amplification gain circuit; The isolation amplification gain circuit is connected to the inverting input terminal of the voltage comparator; The reference voltage source is connected to the non-inverting input of the voltage comparator via a first resistor; The output terminal of the voltage comparator is connected to the non-inverting input terminal of the voltage comparator through a second resistor.

[0034] In some embodiments of the present invention, the voltage divider sampling circuit is used to perform voltage divider sampling on the first DC voltage to obtain a sampled voltage; The isolation amplification gain circuit is used to amplify the sampled voltage; The reference voltage source is used to generate a compensation voltage; the compensation voltage is used to determine the first threshold voltage and the second threshold voltage. The voltage comparator is used to generate the first control signal when the amplified sampled voltage is higher than the first threshold voltage, and to generate the second control signal when the amplified sampled voltage is lower than the second threshold voltage.

[0035] In some embodiments of the present invention, the first control signal is a high-level signal and the second control signal is a low-level signal.

[0036] In some embodiments of the present invention, the expression for the first threshold voltage is as follows: U z1 =U pull ×R2(R1+R2) Among them, U z1U represents the first threshold voltage. pull R1 represents the compensation voltage, R2 represents the first resistor, and R2 represents the second resistor.

[0037] In some embodiments of the present invention, the expression for the second threshold voltage is as follows: U z2 =U pull ×R2(R1+R2)+5V×R1(R1+R2) Among them, U z2 U represents the second threshold voltage. pull R1 represents the compensation voltage, R2 represents the first resistor, and R2 represents the second resistor.

[0038] Figure 2 This is a schematic diagram of the structure of the comparison module provided by the present invention, as shown below. Figure 2 As shown, the comparison module includes a voltage divider sampling circuit, an isolation amplification gain circuit, a reference voltage source, and a voltage comparator.

[0039] The voltage divider sampling circuit includes five resistors R and one resistor R0. The five resistors R are connected in series, and resistor R0 is connected in parallel with one of the resistors R. The voltage divider sampling circuit is used to divide and sample the first DC voltage, and proportionally reduce the voltage to a low voltage signal suitable for processing by the voltage comparator. This low voltage signal is connected to the inverting input of the voltage comparator.

[0040] The non-inverting input of the voltage comparator is connected to a reference voltage source through a first resistor R1. This reference voltage corresponds to the voltage value after voltage division when the DC (DC_INput) input voltage drops to the threshold voltage.

[0041] Meanwhile, the output of the voltage comparator is connected to its non-inverting input through the second resistor R2 to introduce positive feedback, forming a hysteresis comparator (Schmitt trigger) structure, which is used to generate a comparison output signal with hysteresis characteristics.

[0042] By setting a hysteresis comparator, this invention achieves dual threshold switching control, as follows: When the DC_INput DC input voltage gradually decreases from the normal value and falls below the first threshold voltage, the comparator output state flips, the output Buck_Dren signal goes high, the BUCK converter is started and switched to the second power supply path. When the DC_INput DC input voltage gradually rises from a low value and exceeds the second threshold voltage, the comparator output state flips again, the output Buck_Dren signal goes low, the BUCK converter is turned off and switched back to the first power supply path.

[0043] Among them, the sampling voltage V output by the voltage divider sampling circuit ref The calculation is as follows: Vref =U DC_out ×(R0 / / R) / (R0 / / R + 4R) Among them, V ref After isolation and amplification, V is obtained. ref1 The gain factor is gain, and the amplified range is guaranteed to be 0-5V.

[0044] U pull To compensate for the voltage, the hysteresis interval is calculated as follows: First threshold voltage: U z1 =U pull ×R2(R1+R2)+0V Second threshold voltage: U z2 =U pull ×R2(R1+R2)+5V×R1(R1+R2) The first threshold voltage corresponds to the voltage value when the first DC voltage drops to approximately 130V, and the second threshold voltage corresponds to the voltage value when the first DC voltage rises back to approximately 135V.

[0045] The voltage difference (approximately 10V) between the first and second threshold voltages constitutes the hysteresis window. This window effectively prevents repeated switching caused by fluctuations in the input voltage near the threshold. The working hysteresis comparison effect is as follows: Figure 3 As shown.

[0046] The dual-power input seamless switching power supply circuit provided in this embodiment of the invention, by introducing a hysteresis comparator structure and setting dual threshold voltages, avoids the problem of repeated switching caused by fluctuations in the input voltage near the critical point, thereby improving the working stability of the system.

[0047] In some embodiments of the present invention, the top-output module includes: The first and second diodes are connected in parallel; The anode of the first diode is connected to the output terminal of the buck module; The anode of the second diode is connected to the first power input terminal; The cathodes of the first diode and the second diode are connected.

[0048] Figure 4 This is a schematic diagram of the top-output module provided by the present invention, as shown below. Figure 4 As shown, the top output module includes a first diode and a second diode connected in parallel.

[0049] The top module utilizes the opposite direction of its body diodes. When the DC input voltage is lower than the first threshold voltage, the BUCK circuit starts charging. When the BUCK output is higher than the DC bus voltage, the system's DC bus output provides AC power. When the DC input voltage recovers and exceeds the second threshold voltage, the BUCK stops working, and the system's DC bus output becomes a DC power source. The unidirectional conduction of the diodes achieves backflow prevention.

[0050] The dual-power input seamless switching power supply circuit provided in this embodiment of the invention eliminates the need for an external control unit for switching. Voltage fluctuations during dual-power output switching are minimal (below 5%). Dual-power switching is achieved through the unidirectional conductivity of diodes, ensuring that only one power supply powers the system after switching, while the other remains in a dormant state, thus reducing power system losses. Both power supplies are output to the bus via diodes and are configured in a back-to-back connection to prevent reverse current flow. The unidirectional characteristic of the diodes automatically prevents direct short circuits between the two power supplies.

[0051] In some embodiments of the present invention, the step-down module includes a BUCK step-down circuit.

[0052] The step-down module can be a BUCK step-down converter, including a BUCK step-down circuit, which is in standby or off state when the DC input is normal to reduce unnecessary power loss.

[0053] When the comparator outputs a high-level signal, this signal also serves as the enable signal for the BUCK converter, activating the PWM controller, causing the BUCK converter to start working and output a stable DC voltage.

[0054] After the DC_INput DC input returns to normal, the comparator output flips to a low level signal, the BUCK converter is disabled and enters standby mode, and the load is powered by the DC_INput DC input again.

[0055] In some embodiments of the present invention, the first DC voltage is 140V, the AC voltage is 220V, the DC high voltage is 310V, and the second DC voltage is 130V.

[0056] The first DC (DC_INput) voltage is approximately 140V, the AC voltage is 220V AC mains power, the DC high voltage output by the rectifier and filter module is approximately 310V, and the second DC voltage output by the BUCK buck converter is approximately 130V.

[0057] The dual-power input seamless switching power supply circuit provided in this embodiment of the invention can step down the 310V DC high voltage after 220V AC rectification to the required DC bus output using the BUCK step-down converter. The solution is suitable for high-voltage DC application scenarios, fills the gap in the existing dual-power switching solutions in the high-voltage field, and has strong voltage level adaptability.

[0058] The power supply logic timing of the dual-power input seamless switching power supply circuit provided in this embodiment of the invention is as follows: (1) Normal operating state: When the DC_INput DC input voltage is greater than the second threshold voltage, the comparator outputs a low level, the BUCK buck converter is in standby state, and the load is powered by 140V DC input.

[0059] (2) Voltage drop detection and switching: When the DC_INput DC input voltage gradually decreases and falls below the first threshold voltage, the comparator output flips from low level to high level. At the same time, the BUCK buck converter is enabled and begins to output DC voltage. The switching process is directly controlled by the analog comparator to control the power switch, with a response time in the microsecond range and minimal output voltage fluctuation, achieving seamless switching.

[0060] (3) Voltage recovery and switching back: When the DC_INput DC input voltage gradually rises and exceeds the second threshold voltage, the comparator output flips from high level to low level. The load is then powered by the DC_INput DC input.

[0061] This invention provides a dual-power input seamless switching power supply circuit with a simple structure, seamless switching, high control precision, and suitability for high-voltage DC applications. By immediately engaging the BUCK when the DC input voltage drops to the threshold voltage, the output voltage does not drop significantly during the switching process, achieving true seamless switching and ensuring uninterrupted power supply to the load.

[0062] Figure 5 A schematic flowchart of an embodiment of the circuit control method provided by the present invention is shown below. Figure 5 As shown, the circuit control method includes: S501. Receive a first DC input voltage through the first power input terminal, receive an AC voltage through the second power input terminal, and convert the AC voltage into a DC high voltage. S502. When the first DC voltage is lower than the first threshold voltage, a first control signal is output, and based on the first control signal, the step-down module is controlled to step down the DC high voltage to a second DC voltage and output the second DC voltage. S503. When the first DC voltage is higher than the second threshold voltage, a second control signal is output. Based on the second control signal, the buck module is controlled to stop working and the first DC voltage is output; the second threshold voltage is higher than the first threshold voltage.

[0063] In S501, a first DC input voltage is received through the first power input terminal, and an AC voltage is received through the second power input terminal, and the AC voltage is converted into a DC high voltage.

[0064] In S502, the first DC input voltage input to the first power input terminal is detected in real time. When the first DC input voltage is detected to be lower than the first threshold voltage, the first control signal is output to turn off the first power path, while the step-down module is enabled and the second power path is turned on. The second DC voltage output by the step-down module supplies power to the load.

[0065] In S503, when the first DC input voltage is detected to be higher than the second threshold voltage, a second control signal is output to shut off the second power supply path, causing the buck module to stop working, and turning on the first power supply path to restore power supply to the load by the first DC input voltage. The second threshold voltage is higher than the first threshold voltage to form a hysteresis control window.

[0066] In summary, the circuit control method provided by this embodiment of the invention sets a first threshold voltage and a second threshold voltage. When the first DC voltage is higher than the second threshold voltage, a second control signal is output, and the buck module is in standby mode, consuming no additional power, and outputting the first DC voltage to the load. When the first DC voltage is lower than the first threshold voltage, a first control signal is output, and the buck module immediately intervenes to step down the high DC voltage to the second DC voltage and outputs the second DC voltage to the load. The output voltage does not drop significantly during the switching process, achieving true seamless switching and ensuring uninterrupted power supply to the load. By setting dual threshold voltages, the control accuracy is improved, avoiding repeated switching problems caused by fluctuations in the input voltage near the critical point, and improving switching stability.

[0067] The dual-power input seamless switching power supply circuit and circuit control method provided by this invention have the following advantages: (1) Seamless switching: After the DC input drops to the threshold voltage, the BUCK immediately intervenes and the output voltage does not drop significantly during the switching process, achieving true seamless switching and ensuring uninterrupted power supply to the load.

[0068] (2) High switching stability: By introducing a hysteresis comparator structure and setting a double threshold voltage, the repeated switching problem caused by the fluctuation of the input voltage near the critical point is avoided, thus improving the working stability of the system.

[0069] (3) Simple circuit and low cost: The core control part only requires a voltage comparator and a few discrete components. It does not require complex microcontroller (MCU) programming and expensive dedicated switching chips. The circuit structure is simple, easy to implement, and low in cost.

[0070] (4) Strong voltage level adaptability: The BUCK step-down converter can step down the 310V DC high voltage after 220V AC rectification to the required DC bus output. The solution is suitable for high voltage DC application scenarios and fills the gap of existing dual power supply switching solutions in the high voltage field.

[0071] (5) Low power loss: When the DC input is normal, the BUCK converter is in standby mode and does not consume extra power; it only starts working when the main power supply drops, resulting in lower overall system power consumption.

[0072] (6) Good scalability: By adding communication modules and status indication functions, remote monitoring and on-site status display can be easily realized to meet the needs of intelligent power management.

[0073] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0074] The above provides a detailed description of the dual-power input seamless switching power supply circuit and circuit control method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A dual-power input seamless switching power supply circuit, characterized in that, include: The system includes a first power input terminal, a second power input terminal, a rectifier and filter module, a step-down module, a comparator module, and a top-output module. The first power input terminal is connected to the comparison module and the top output module respectively; The second power input terminal, the rectifier and filter module, the step-down module, and the top output module are connected in sequence; The enable control terminal of the buck module is connected to the comparator module; The first power input terminal is used to receive the first DC voltage; The second power input terminal is used to receive AC voltage; The rectifier and filter module is used to convert the AC voltage into a DC high voltage. The comparison module is configured to output a first control signal when the first DC voltage is lower than a first threshold voltage, and to output a second control signal when the first DC voltage is higher than a second threshold voltage; wherein the second threshold voltage is higher than the first threshold voltage. The step-down module is used to step down the DC high voltage to a second DC voltage based on the first control signal, or to stop working based on the second control signal; The top output module is used to output the second DC voltage based on the first control signal, or to output the first DC voltage based on the second control signal.

2. The dual-power input seamless switching power supply circuit according to claim 1, characterized in that, The comparison module includes: Voltage divider sampling circuit, isolation amplifier gain circuit, reference voltage source and voltage comparator; The voltage divider sampling circuit is connected between the first power input terminal and the isolation amplification gain circuit; The isolation amplification gain circuit is connected to the inverting input terminal of the voltage comparator; The reference voltage source is connected to the non-inverting input of the voltage comparator via a first resistor; The output terminal of the voltage comparator is connected to the non-inverting input terminal of the voltage comparator through a second resistor.

3. The dual-power input seamless switching power supply circuit according to claim 2, characterized in that, The voltage divider sampling circuit is used to perform voltage divider sampling on the first DC voltage to obtain the sampled voltage; The isolation amplification gain circuit is used to amplify the sampled voltage; The reference voltage source is used to generate a compensation voltage; the compensation voltage is used to determine the first threshold voltage and the second threshold voltage. The voltage comparator is used to generate the first control signal when the amplified sampled voltage is higher than the first threshold voltage, and to generate the second control signal when the amplified sampled voltage is lower than the second threshold voltage.

4. The dual-power input seamless switching power supply circuit according to claim 3, characterized in that, The expression for the first threshold voltage is as follows: IN z1 =U pull ×R2 (R1+R2) Among them, U z1 U represents the first threshold voltage. pull R1 represents the compensation voltage, R2 represents the first resistor, and R2 represents the second resistor.

5. The dual-power input seamless switching power supply circuit according to claim 3, characterized in that, The expression for the second threshold voltage is as follows: IN z2 =U pull ×R2(R1+R2)+5V×R1(R1+R2) Among them, U z2 U represents the second threshold voltage. pull R1 represents the compensation voltage, R2 represents the first resistor, and R2 represents the second resistor.

6. The dual-power input seamless switching power supply circuit according to claim 1, characterized in that, The top-output module includes: The first and second diodes are connected in parallel; The anode of the first diode is connected to the output terminal of the buck module; The anode of the second diode is connected to the first power input terminal; The cathodes of the first diode and the second diode are connected.

7. The dual-power input seamless switching power supply circuit according to claim 1, characterized in that, The first control signal is a high-level signal, and the second control signal is a low-level signal.

8. The dual-power input seamless switching power supply circuit according to claim 1, characterized in that, The step-down module includes a BUCK step-down circuit.

9. The dual-power input seamless switching power supply circuit according to claim 1, characterized in that, The first DC voltage is 140V, the AC voltage is 220V, the DC high voltage is 310V, and the second DC voltage is 130V.

10. A circuit control method, characterized in that, The dual-power input seamless switching power supply circuit according to any one of claims 1 to 9 comprises: The system receives a first DC input voltage through the first power input terminal and an AC voltage through the second power input terminal, and converts the AC voltage into a DC high voltage. When the first DC voltage is lower than the first threshold voltage, a first control signal is output. Based on the first control signal, the step-down module is controlled to step down the high DC voltage to a second DC voltage and output the second DC voltage. When the first DC voltage is higher than the second threshold voltage, a second control signal is output. Based on the second control signal, the buck module is controlled to stop working and the first DC voltage is output; the second threshold voltage is higher than the first threshold voltage.

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