A voltage-stabilized power supply capable of adapting to ultra-low voltage operation

Abstract

The present invention relates to a voltage-stabilized power supply, and in particular to a voltage-stabilized power supply capable of adapting to ultra-low voltage operation. It comprises a transformer, a self-power supply system management unit, and a voltage-stabilized management and signal processor, and is characterized in that the self-power supply system management unit comprises an input voltage acquisition module, a reference value adjustable module, a voltage comparator, a multi-channel voltage coordination module, a first and a second synchronous buck circuit, and a first and a second rectifier filter circuit; the self-power supply system management unit adopts two-way selection for the working power supply, and controls and coordinates one of the synchronous buck circuits as the main voltage output by collecting the input voltage. The purpose is to design a voltage-stabilized power supply capable of adapting to ultra-low voltage operation, which can be smoothly started when the city grid voltage is very low, and can ensure that the circuit can withstand high-voltage shocks when the voltage is high. Compared with the prior art, it has the advantages of a wider input voltage range, strong intelligence, stable self-working voltage, and high system working stability.

Description

Technical Field

[0001] The invention relates to a voltage-stabilized power supply, in particular to a voltage-stabilized power supply capable of adapting to ultra-low voltage operation. Background Art

[0002] At present, the conventional input voltage of the AC stabilized power supply in the industry is between 135V and 270V, and there are also special requirements for the voltage to be 90V-270V. The market also calls this type of AC stabilized power supply an ultra-low voltage stabilized power supply, which basically meets the market demand. However, for countries and regions with very backward economic development, the city grid voltage sometimes reaches a maximum of AC285V and sometimes a minimum of AC45V, and the voltage is extremely unstable. When the existing stabilized power supply has a very low city grid voltage, it is difficult for the AC stabilized power supply to realize its own power supply and it is not easy to start smoothly; under high voltage conditions, it cannot guarantee that the circuit can withstand high voltage shocks. Summary of the invention

[0003] The purpose of the present invention is to design a voltage-stabilized power supply which can be started smoothly when the city grid voltage is very low and can ensure that the circuit can withstand high-voltage impact under high-voltage conditions and is adaptable to ultra-low voltage operation.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a voltage-stabilized power supply capable of adapting to ultra-low voltage operation, comprising a transformer, a self-power supply system management unit and a voltage-stabilized management and signal processor, characterized in that the self-power supply system management unit comprises an input voltage acquisition module, a reference value adjustable module, a voltage comparator, a multi-channel voltage coordination module, a first synchronous buck circuit, a first rectifier and filter circuit, a second synchronous buck circuit, and a second rectifier and filter circuit, wherein:

[0005] The input voltage acquisition module acquires the input voltage of the transformer, the output end of the input voltage acquisition module is connected to the first input end of the voltage comparator, the output end of the reference value adjustable module is connected to the second input end of the voltage comparator, the output end of the voltage comparator is connected to the input end of the multi-channel voltage coordination module, and the first output end and the second output end of the multi-channel voltage coordination module are respectively connected to the control ends of the first synchronous buck circuit and the second synchronous buck circuit;

[0006] A first secondary line and a second secondary line are provided on the secondary coil of the transformer, and input ends of the first rectifier and filter circuit and the second rectifier and filter circuit are respectively connected to two ends of the first secondary line and two ends of the second secondary line, and output ends of the first rectifier and filter circuit and the second rectifier and filter circuit are respectively connected to input ends of the first synchronous buck circuit and the second synchronous buck circuit, and output ends of the first synchronous buck circuit and the second synchronous buck circuit are connected to working power input ends of each circuit module.

[0007] In order to select appropriate rectification, filtering and buck-stabilization circuits according to different city grid voltage conditions, the present invention further configures the technical solution: the multi-channel voltage coordination module includes a first delay circuit, a second delay circuit, an OR gate circuit and a NOR gate circuit, the first input end of the OR gate circuit and the NOR gate circuit are connected to the output end of the voltage comparator, the output end of the first delay circuit is connected to the second input end of the NOR gate circuit, the output end of the second delay circuit is connected to the second input end of the OR gate circuit, the output end of the NOR gate circuit is connected to the control end of the first synchronous buck circuit, and the output end of the OR gate circuit is connected to the control end of the second synchronous buck circuit.

[0008] In order to further improve the voltage stabilization effect of the system's own working voltage, the present invention further configures the technical solution: the first synchronous buck circuit or the second synchronous buck circuit includes a control chip of model L6727, a first N-channel MOS tube, a second N-channel MOS tube, a high-frequency inductor, a capacitor, a voltage sampling circuit, a current acquisition circuit and a control transistor, wherein:

[0009] The two ends of the capacitor are connected to the output end of the first rectifying and filtering circuit or the second rectifying and filtering circuit, and the voltage sampling circuit is connected in parallel to the capacitor.

[0010] The source and drain of the first N-channel MOS transistor are connected in series to a line between the positive end of the capacitor and the positive end of the output voltage of the first rectifier and filter circuit or the second rectifier and filter circuit.

[0011] The high-frequency inductor is connected in series to the line between the drain of the first N-channel MOS tube and the positive end of the capacitor.

[0012] The source and drain of the second N-channel MOS transistor are respectively connected to the output voltage negative terminal of the first rectifying and filtering circuit or the second rectifying and filtering circuit and the drain of the first N-channel MOS transistor.

[0013] The gate of the first N-channel MOS transistor is connected to the upper bridge control terminal of the control chip, and the gate of the second N-channel MOS transistor is connected to the lower bridge control terminal of the control chip.

[0014] The sampling voltage output terminal of the voltage sampling circuit is connected to the voltage feedback terminal of the control chip.

[0015] The collector and emitter of the control transistor are respectively connected to the power supply terminal and the ground terminal of the control chip, and the base of the control transistor is connected to the output terminal of the NOR gate circuit or the OR gate circuit.

[0016] In order to further ensure that the machine can be started smoothly when the city grid voltage is very low, and to ensure that the circuit can withstand high voltage shock under high voltage conditions, the technical solution is further configured as follows:

[0017] The AC steady-state input voltage of the first rectifier and filter circuit is 33-38V, the stable output DC voltage Vcc is 40V-45V, and the DC voltage Vcc at the start-up moment is 12V-70V;

[0018] The AC steady-state input voltage of the second rectifier and filter circuit is 13-17V, the stable output DC voltage Vcc is 15V-20V, and the DC voltage Vcc at the start-up instant is 4V-45V.

[0019] In order to further ensure that the system can adapt to ultra-low voltage operation, the present invention further configures the technical solution: the voltage-stabilized power supply is adapted to a mains voltage between AC45V and AC285V, and the working power supply of each circuit module is 12V. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a block diagram of the working principle of this embodiment.

[0021] Figure 2 This is a block diagram of the working principle of the multi-channel voltage coordination module.

[0022] Figure 3 A simplified circuit diagram of the first or second synchronous buck circuit.

[0023] Figure 4 A schematic diagram of the first or second synchronous buck circuit as an LC charging loop.

[0024] Figure 5 A schematic diagram of the first or second synchronous buck circuit as an LC discharge loop. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 1 As shown, this embodiment includes a transformer T, a power supply system management unit and a voltage stabilization management and signal processor, wherein the power supply system management unit includes an input voltage acquisition module, a reference value adjustable module, a voltage comparator, a multi-channel voltage coordination module, a first synchronous buck circuit, a first rectifier and filter circuit, a second synchronous buck circuit, and a second rectifier and filter circuit, wherein:

[0027] The city grid voltage applicable to this embodiment is between AC45V and AC285V, and the working power supply of each circuit module is 12V.

[0028] The AC steady-state input voltage of the first rectifier and filter circuit is 33-38V, the stable output DC voltage Vcc is 40V-45V, and the DC voltage Vcc at the moment of startup is 12V-70V;

[0029] The AC steady-state input voltage of the second rectifier and filter circuit is 13-17V, the stable output DC voltage Vcc is 15V-20V, and the DC voltage Vcc at the start-up instant is 4V-45V.

[0030] When the input mains voltage is 45V and the machine is turned on instantly, the DC voltage Vcc of the first rectifier and filter circuit is 12V, and the DC voltage Vcc of the second rectifier and filter circuit is 4V;

[0031] When the input mains voltage of 285V is turned on instantly, the DC voltage Vcc of the first rectifier and filter circuit is 70V, and the DC voltage Vcc of the second rectifier and filter circuit is 45V.

[0032] The input voltage acquisition module acquires the input voltage of the transformer T, the output end Vi-Signal of the input voltage acquisition module is connected to the first input end of the voltage comparator after passing through the signal filtering circuit and the signal amplifying circuit, the output end of the reference value adjustable module is connected to the second input end of the voltage comparator, the output end of the voltage comparator is connected to the input end of the multi-channel voltage coordination module, and the first output end and the second output end of the multi-channel voltage coordination module are respectively connected to the control ends of the first synchronous buck circuit and the second synchronous buck circuit;

[0033] A first secondary line T1 and a second secondary line T2 are provided on the secondary coil of the transformer T, and input ends of the first rectifier and filter circuit and the second rectifier and filter circuit are respectively connected to two ends of the first secondary line T1 and two ends of the second secondary line T2, and output ends of the first rectifier and filter circuit and the second rectifier and filter circuit are respectively connected to input ends of the first synchronous buck circuit and the second synchronous buck circuit, and output ends of the first synchronous buck circuit and the second synchronous buck circuit are connected to working power input ends of each circuit module.

[0034] like Figure 2As shown, the main function of the multi-channel voltage coordination module is to manage the synchronous buck circuit, which can turn on and off the synchronous buck circuit. It includes a first delay circuit, a second delay circuit, an OR gate circuit and an NOR gate circuit. The first input end of the OR gate circuit and the NOR gate circuit are connected to the output end of the voltage comparator, the output end of the first delay circuit is connected to the second input end of the NOR gate circuit, the output end of the second delay circuit is connected to the second input end of the OR gate circuit, the output end of the NOR gate circuit is connected to the control end of the first synchronous buck circuit, and the output end of the OR gate circuit is connected to the control end of the second synchronous buck circuit.

[0035] like Figure 3 As shown, the first synchronous buck circuit includes a control chip U of model L6727, a first N-channel MOS transistor Q1, a second N-channel MOS transistor Q2, a high-frequency inductor L, a capacitor C2, a voltage sampling circuit (R1, R2), a current acquisition circuit R3 and a control transistor Q3, wherein:

[0036] The two ends of the capacitor C2 are connected to the output end of the first rectifying and filtering circuit or the second rectifying and filtering circuit, and the voltage sampling circuit (R1, R2) is connected in parallel to the capacitor C2.

[0037] The source and drain of the first N-channel MOS transistor Q1 are connected in series to a line between the positive end of the capacitor C2 and the positive end of the output voltage of the first rectifier and filter circuit or the second rectifier and filter circuit.

[0038] The high-frequency inductor L is connected in series to the line between the drain of the first N-channel MOS transistor Q1 and the positive end of the capacitor C2.

[0039] The source and drain of the second N-channel MOS transistor Q2 are connected to the output voltage negative terminal of the first rectifier and filter circuit and the drain of the first N-channel MOS transistor Q1 respectively.

[0040] The gate of the first N-channel MOS transistor Q1 is connected to the upper bridge control terminal DH of the control chip U, and the gate of the second N-channel MOS transistor Q2 is connected to the lower bridge control terminal DL of the control chip U.

[0041] The sampling voltage output terminal of the voltage sampling circuit (R1, R2) is connected to the voltage feedback terminal VF of the control chip U,

[0042] The collector and emitter of the control transistor Q3 are connected to the power supply terminal Vdd and the ground terminal of the control chip U respectively, and the base of the control transistor Q3 is connected to the output terminal of the NOR gate circuit.

[0043] Similarly, the circuit connection structure of the second synchronous buck circuit is basically the same as that of the first synchronous buck circuit, except that the base of the control transistor in the second synchronous buck circuit is connected to the output end of the OR gate circuit.

[0044] When the system is turned on, the voltage comparator takes priority in the work, comparing the sampling value of the input voltage acquisition module with the reference value of the voltage reference value adjustable module. If the input voltage sampling value is greater than the reference value, the voltage comparator outputs a high level, indicating that the input mains voltage is higher than the set voltage value, otherwise the input mains voltage is lower than the set voltage value.

[0045] When the voltage comparator outputs a high level, it means that the input mains voltage is higher than the set voltage value. If the machine is turned on in this situation, the multi-channel voltage coordination module will prioritize shutting down the first synchronous buck circuit to prevent high-voltage shocks, and choose to open the second synchronous buck circuit. Only when the voltage stabilization system of the entire machine is normal and the power supply system voltage is stable, can the output of the second synchronous buck circuit be maintained. Such a coordination mechanism effectively protects the high-voltage shock circuit.

[0046] When the voltage comparator outputs a low level, it means that the input mains voltage is lower than the set voltage value. If this happens, the multi-channel voltage coordination module will first turn off the second synchronous buck circuit and choose to turn on the first synchronous buck circuit. Only when the voltage stabilization system of the whole machine is normal, the first synchronous buck circuit will be turned off and the second synchronous buck circuit will be turned on again. This coordination mechanism effectively solves the problem of being unable to start up in low voltage conditions.

[0047] The process of opening and closing the synchronous buck circuit by the multi-channel voltage coordination module is as follows:

[0048] At the moment of power-on, the outputs of the first delay circuit and the second delay circuit are both 0.

[0049] At the moment of power-on, when the voltage comparator outputs a low-level signal, the output signal Eanble2 of the OR gate circuit is 0, the control transistor in the second synchronous buck circuit is cut off, and the second synchronous buck circuit is turned off. At this time, the output signal Eanble1 of the NOR gate circuit is 1, the control transistor Q3 in the first synchronous buck circuit is turned on, and the first synchronous buck circuit starts working.

[0050] At the moment of power-on, when the voltage comparator outputs a high-level signal, the output signal Eanble2 of the OR gate circuit is 1, the control transistor in the second synchronous buck circuit is turned on, and the second synchronous buck circuit starts working. At this time, the output signal Eanble1 of the NOR gate circuit is 0, the control transistor Q3 in the first synchronous buck circuit is turned off, and the first synchronous buck circuit is turned off.

[0051] When the system is stable after a delay of 100ms, the outputs of the first delay circuit and the second delay circuit are both 1. At this time, regardless of whether the voltage comparator outputs a low-level signal or a high-level signal, the output signal of the OR gate circuit is 1, and the output signal of the NOR gate circuit is 0. The first synchronous buck circuit is turned off and the second synchronous buck circuit starts working. After the system is stable, the system output voltage always maintains the output of the second synchronous buck circuit.

[0052] The step-down and voltage stabilization process of the first synchronous buck circuit and the second synchronous buck circuit is as follows:

[0053] For example Figure 3 As shown, the main function of the first or second synchronous buck circuit is to stabilize the output voltage of 12V, and it also has the characteristic of low power consumption.

[0054] The closing and opening of the first or second synchronous buck circuit is controlled by the control transistor Q3, and the control transistor Q3 is controlled by the multi-channel voltage coordination module.

[0055] When the first or second synchronous buck circuit is working, when the upper bridge control terminal DH of the control chip U outputs 1 and the lower bridge control terminal DL outputs 0, the first N-channel MOS transistor Q1 is turned on, the second N-channel MOS transistor Q2 is turned off, and the DC current of the power supply Vcc passes through the first N-channel MOS transistor Q1, the high-frequency inductor L and the current collection circuit R3 to form an LC charging loop (such as Figure 4 As shown), at this time, the power supply Vcc charges the capacitor C2 and the high-frequency inductor L. When the voltage is charged to be greater than 12V, the sampling voltage signal of the voltage sampling circuit (R1, R2) is fed back to the control chip U, so that the upper bridge control terminal DH of the control chip U outputs 0, and the first N-channel MOS tube Q1 is turned off.

[0056] When the output of the upper bridge control terminal DH of the control chip U is 0 and the output of the lower bridge control terminal DL is 0, a very short period of time is reserved, which is called the dead time. At this time, the circuit loses charging, the capacitor C2 maintains the output, the output voltage continues to decrease, and the sampling voltage signal of the voltage sampling circuit (R1, R2) is fed back to the control chip U, so that the output of the lower bridge control terminal DL of the control chip U is 1, and the second N-channel MOS tube Q2 is turned on.

[0057] When the upper bridge control terminal DH of the control chip U outputs 0 and the lower bridge control terminal DL outputs 1, the first N-channel MOS transistor Q1 is turned off, the second N-channel MOS transistor Q2 is turned on, and the current of the high-frequency inductor L flows to the capacitor C2 and the second N-channel MOS transistor Q2 to form an LC discharge loop (such as Figure 5As shown), at this time, the current of the high-frequency inductor L continues to charge the capacitor C2 to maintain the output voltage. When the output voltage is less than 12V, the sampling voltage signal of the voltage sampling circuit (R1, R2) is fed back to the control chip U, so that the upper bridge control terminal DH of the control chip U outputs 0, the lower bridge control terminal DL outputs 0, the first N-channel MOS tube Q1 is turned on again, and the second N-channel MOS tube Q2 is turned off. The above process is repeated to form a complete closed-loop system, and the input and output voltage changes can be stabilized by adjusting the duty cycle.

[0058] In summary, the present invention has the following advantages compared with the prior art:

[0059] 1. The system's own working voltage has a good stabilization effect. Due to the use of the L6727 control chip and N-channel MOS tube control, the system's own working voltage has a very good stabilization effect, low power consumption and no noise.

[0060] 2. The input voltage range is wider to ensure the normal startup of the system. There are two sets of secondary line voltages. The system can automatically switch the corresponding rectifier filter and synchronous buck circuit according to the grid voltage. It is highly intelligent and ensures the normal startup of the system. At the same time, it reduces the impact and increases the life of the machine and equipment.

[0061] 3. Improve the stability of the system. Voltage stabilization management and signal processors have very high requirements for the stability of the power supply system. If there is serious interference, it will affect the accuracy and misoperation. Since the system's own power supply is independent of other systems, independent control and independent protection processing, the stability of the system's voltage stabilization processing is greatly improved.

[0062] 4. It has a power-on delay function. The power-on delay time can be customized through the delay circuit to better protect the safety of user equipment.

Claims

1. A voltage-stabilized power supply capable of adapting to ultra-low voltage operation, comprising a transformer T, a power supply system management unit, and a voltage-stabilized management and signal processor, characterized in that The self-power supply system management unit includes an input voltage acquisition module, a reference value adjustable module, a voltage comparator, a multi-channel voltage coordination module, a first synchronous buck circuit, a first rectifier and filter circuit, a second synchronous buck circuit, and a second rectifier and filter circuit, wherein: The input voltage acquisition module acquires the input voltage of the transformer T, the output terminal Vi-Signal of the input voltage acquisition module is connected to the first input terminal of the voltage comparator, the output terminal of the reference value adjustable module is connected to the second input terminal of the voltage comparator, the output terminal of the voltage comparator is connected to the input terminal of the multi-channel voltage coordination module, and the first output terminal and the second output terminal of the multi-channel voltage coordination module are respectively connected to the control terminals of the first synchronous buck circuit and the second synchronous buck circuit; A first secondary line T1 and a second secondary line T2 are provided on the secondary coil of the transformer T, input ends of the first rectifying and filtering circuit and the second rectifying and filtering circuit are respectively connected to two ends of the first secondary line T1 and two ends of the second secondary line T2, output ends of the first rectifying and filtering circuit and the second rectifying and filtering circuit are respectively connected to input ends of the first synchronous buck circuit and the second synchronous buck circuit, and output ends of the first synchronous buck circuit and the second synchronous buck circuit are connected to working power input ends of each circuit module; The multi-channel voltage coordination module comprises a first delay circuit, a second delay circuit, an OR gate circuit and a NOR gate circuit, wherein the first input end of the OR gate circuit and the NOR gate circuit are connected to the output end of the voltage comparator, the output end of the first delay circuit is connected to the second input end of the NOR gate circuit, the output end of the second delay circuit is connected to the second input end of the OR gate circuit, the output end of the NOR gate circuit is connected to the control end of the first synchronous buck circuit, and the output end of the OR gate circuit is connected to the control end of the second synchronous buck circuit; The first synchronous buck circuit or the second synchronous buck circuit comprises a control chip U of model L6727, a first N-channel MOS transistor Q1, a second N-channel MOS transistor Q2, a high-frequency inductor L, a capacitor C2, voltage sampling circuits R1, R2 and a control transistor Q3, wherein: The two ends of the capacitor C2 are connected to the output end of the first rectifying and filtering circuit or the second rectifying and filtering circuit, and the voltage sampling circuits R1 and R2 are connected in parallel to the capacitor C2. The source and drain of the first N-channel MOS transistor Q1 are connected in series to a line between the positive end of the capacitor C2 and the positive end of the output voltage of the first rectifier and filter circuit or the second rectifier and filter circuit. The high-frequency inductor L is connected in series to the line between the drain of the first N-channel MOS transistor Q1 and the positive end of the capacitor C2. The source and drain of the second N-channel MOS transistor Q2 are connected to the output voltage negative terminal of the first rectifying and filtering circuit or the second rectifying and filtering circuit and the drain of the first N-channel MOS transistor Q1 respectively. The gate of the first N-channel MOS transistor Q1 is connected to the upper bridge control terminal DH of the control chip U, and the gate of the second N-channel MOS transistor Q2 is connected to the lower bridge control terminal DL of the control chip U. The sampling voltage output terminals of the voltage sampling circuits R1 and R2 are connected to the voltage feedback terminal VF of the control chip U. The collector and emitter of the control transistor Q3 are connected to the power supply terminal Vdd and the ground terminal of the control chip U respectively, and the base of the control transistor Q3 is connected to the output terminal of the NOR gate circuit or the OR gate circuit.

2. A voltage-stabilized power supply capable of adapting to ultra-low voltage operation according to claim 1, characterized in that The AC steady-state input voltage of the first rectifier and filter circuit is 33-38V, the stable output DC voltage Vcc is 40V-45V, and the DC voltage Vcc at the moment of startup is 12V-70V; The AC steady-state input voltage of the second rectifier and filter circuit is 13-17V, the stable output DC voltage Vcc is 15V-20V, and the DC voltage Vcc at the start-up instant is 4V-45V.

3. A voltage-stabilized power supply capable of adapting to ultra-low voltage operation according to claim 2, characterized in that The voltage-stabilized power supply is adapted to a mains voltage between AC45V and AC285V, and the working power supply of each circuit module is 12V.

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