Power supply state switching circuit and intelligent cabinet

Abstract

The utility model provides a power supply state switching circuit and an intelligent cabinet. The power supply state switching circuit comprises a first power supply unit, a second power supply unit and a switching unit, the first power supply unit is connected with a power supply battery and is used for reducing initial voltage provided by the power supply battery and outputting stability maintaining voltage obtained after voltage reduction to the switching unit; the second power supply unit is connected with an external power supply and is used for reducing the voltage of the external power supply to a working voltage and outputting the working voltage to the switching unit; the switching unit is used for receiving the stability maintaining voltage and the working voltage, when the external power supply is switched off, the first power supply unit supplies power to the main controller, and when the external power supply is switched on, the second power supply unit is switched to supply power to the main controller and the circuit load, so that low-power-consumption power supply of the battery pack is realized, and the power supply efficiency is improved. And switching between normal power supply and low-power-consumption power supply is realized when the external power supply is recovered, so that energy loss is avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of power supply for smart cabinets, and specifically relates to a power supply state switching circuit and a smart cabinet. Background Art

[0002] A smart cabinet is a device that uses a smart cabinet control system to open and close the cabinet door, making it convenient to store and retrieve objects. It is widely used in public living places including express delivery, supermarkets, and storage. Smart cabinets usually need to be connected to the power grid for energy supply. Under normal circumstances, the power grid is stable and can maintain the stable operation of various devices in the smart cabinet. When the power grid is upgraded or an unexpected situation occurs, resulting in power outages, the battery pack installed in the smart cabinet needs to temporarily supply energy to various devices.

[0003] However, when the battery pack is supplying power, it will supply power to all electrical equipment in the cabinet, and even to loads that do not need to be running at the moment, causing the battery pack to lose power quickly and cause energy loss. When the mains power is restored, it is impossible to switch to the mains power supply in time. Therefore, how to make the battery pack perform low-power supply when supplying power, and how to achieve the state switching between normal power supply and low-power supply, is an urgent problem to be solved. Utility Model Content

[0004] The present application provides a power supply state switching circuit and an intelligent cabinet to solve the problem of how to enable a battery pack to perform low-power supply when supplying power, and how to achieve state switching between normal power supply and low-power supply.

[0005] In order to solve the above technical problems, the present application provides a power supply state switching circuit, including a first power supply unit, a second power supply unit and a switching unit;

[0006] The first power supply unit is connected to the power supply battery, and is used to step down the initial voltage provided by the power supply battery, and output the stabilizing voltage obtained after the step-down to the switching unit;

[0007] The second power supply unit is connected to an external power supply, and is used to step down the voltage of the external power supply to an operating voltage, and output the operating voltage to the switching unit;

[0008] The switching unit is used to receive the stabilization voltage and the working voltage. When the external power supply is disconnected, the first power supply unit supplies power to the main controller. When the external power supply is connected, the second power supply unit is switched to supply power to the main controller and the circuit load; wherein the working voltage is greater than the stabilization voltage.

[0009] As a further improvement of the present application, the first power supply unit includes a voltage stabilizing element, a filtering and current limiting element, and a first voltage reducing element;

[0010] The voltage stabilizing element is connected to the power supply battery and is used to stabilize the initial voltage provided by the power supply battery;

[0011] The filtering and current limiting element is connected to the voltage stabilizing element and is used to filter out high-frequency ripples in the initial voltage provided by the power supply battery;

[0012] The first voltage-reducing element is connected to the filtering and current-limiting element, and is used to reduce the initial voltage after filtering the high-frequency ripple, and output the stabilizing voltage obtained after the reduction to the switching unit.

[0013] As a further improvement of the present application, the voltage stabilizing element includes a first diode D1, a first capacitor C1 and a first transient suppression diode TVS1, the anode of the first diode D1 is connected to the power supply battery, the cathode of the first diode D1 is connected to the first capacitor C1, the first transient suppression diode TVS1 is arranged in parallel at both ends of the first capacitor C1, and the anode of the first transient suppression diode TVS1 is connected to the first capacitor C1 and then grounded;

[0014] The filtering and current-limiting element comprises a second capacitor C2, a third capacitor C3 and a first resistor R1, the cathode of the first transient suppression diode TVS1 is connected to the first capacitor C1 and then connected to the second capacitor C2, the first resistor R1 and the third capacitor C3 are arranged in parallel at both ends of the second capacitor C2, and one end of the third capacitor C3 is connected to the second capacitor C2 and then grounded;

[0015] The first voltage-reducing element includes a first voltage-stabilizing diode Z1, a first transistor Q1, and a second transistor Q2. The first voltage-stabilizing diode Z1 is arranged in parallel at both ends of the third capacitor C3. The other end of the third capacitor C3 is connected to the cathode of the first voltage-stabilizing diode Z1 and then connected to the base of the first transistor Q1. The collector of the first transistor Q1 is connected to a second resistor R2. The other end of the second resistor R2 is connected between the first resistor R1 and the second capacitor C2. The emitter of the first transistor Q1 is connected to the base of the second transistor Q2. The collector of the second transistor Q2 is connected to the second resistor R2 and then connected between the first capacitor C1 and the first transient suppression diode TVS1. The emitter of the second transistor Q2 is connected to a second diode D2. The anode of the second diode D2 is connected to the emitter of the second transistor Q2. The anode of the second diode D2 is connected to the switching unit to output the stabilizing voltage obtained after voltage reduction to the switching unit.

[0016] As a further improvement of the present application, the first power supply unit further includes a current limiting protection element and an overvoltage protection element;

[0017] The current limiting protection element is used to provide current limiting protection for the first power supply unit, and the current limiting protection element includes a third resistor R3 and a fourth resistor R4.

[0018] The third resistor R3 is arranged between the collector of the second transistor Q2 and the second resistor R2. The third resistor R3 and the second resistor R2 are connected together and then connected between the first capacitor C1 and the first transient suppression diode TVS1. The fourth resistor R4 is arranged in parallel at both ends of the third resistor R3.

[0019] The overvoltage protection element is used to absorb the part that exceeds the stabilizing voltage to provide overvoltage protection for the first power supply unit. The overvoltage protection element includes a third capacitor C3 and a second Zener diode Z2. The second Zener diode Z2 is arranged in parallel at both ends of the third capacitor C3. The anode of the second Zener diode Z2 is connected to one end of the third capacitor C3 and then grounded. The cathode of the second Zener diode Z2 is connected to the other end of the third capacitor C3 and then connected between the anode of the second diode D2 and the switching unit.

[0020] As a further improvement of the present application, the second power supply unit includes a power supply element, a second voltage reduction element and an output protection element;

[0021] The power supply element is connected to an external power supply, and is turned on when the external power supply is greater than the starting power supply of the power supply element, so that the second voltage-reducing element reduces the voltage of the external power supply to the working voltage;

[0022] The output protection element is used to absorb a portion exceeding the operating voltage to stabilize the voltage output by the second power supply unit to the operating voltage.

[0023] As a further improvement of the present application, the power supply element includes a power supply chip U1, a third transistor Q3, a fourth transistor Q4, a fourth capacitor C4 and a first electrolytic capacitor CD1;

[0024] The base of the third triode Q3 is connected to an external power supply through a fifth resistor R5, a sixth resistor R6 is connected between the emitter of the third triode Q3 and the base of the third triode Q3, one end of the sixth resistor R6 is connected to the base of the third triode Q3 after being connected to the fifth resistor R5, and the other end of the sixth resistor R6 is connected to the emitter of the third triode Q3 after being grounded;

[0025] A seventh resistor R7 is connected between the collector of the third transistor Q3 and the base of the fourth transistor Q4, an eighth resistor R8 is connected between the emitter of the fourth transistor Q4 and the base of the fourth transistor Q4, and the collector of the fourth transistor Q4 is connected to the VIN pin of the power supply chip U1; the positive electrode of the first electrolytic capacitor CD1 and the fourth capacitor C4 are both connected between the collector of the fourth transistor Q4 and the VIN pin of the power supply chip U1, the negative electrode of the first electrolytic capacitor CD1 and the fourth capacitor C4 are connected to ground after being connected in common, a second transient suppression diode TVS2 is connected in parallel at both ends of the fourth capacitor C4, and a fifth capacitor C5 is connected between the VIN pin of the power supply chip U1 and the VC pin of the power supply chip U1;

[0026] The second voltage-reducing element includes a first inductor L1 and a second diode D2. The SW pin of the power supply chip U1 and the EP pin of the power supply chip U1 are connected to the first inductor L1. The first inductor L1 is connected to the switching unit through a ninth resistor R9 and a tenth resistor R10 to output the working voltage obtained after voltage reduction to the switching unit. The cathode of the second diode D2 is connected between the SW pin of the power supply chip U1 and the first inductor L1, and the anode of the second diode D2 is grounded.

[0027] The output protection element includes a third voltage stabilizing diode Z3, a second electrolytic capacitor CD2 is further connected between the ninth resistor R9 and the tenth resistor R10, a positive electrode of the second electrolytic capacitor CD2 is connected to the ninth resistor R9 and then connected to the CSN pin of the power supply chip U1, and the CSP pin of the power supply chip U1 is connected between the first inductor L1 and the ninth resistor R9;

[0028] A sixth capacitor C6 is arranged in parallel at both ends of the second electrolytic capacitor CD2, an eleventh resistor R11 and a twelfth resistor R12 are arranged in parallel at both ends of the sixth capacitor C6, an FB pin of the power supply chip U1 is connected between the eleventh resistor R11 and the twelfth resistor R12, a seventh capacitor C7 is arranged in parallel at both ends of the eleventh resistor R11, an eighth capacitor C8 is arranged in parallel at both ends of the twelfth resistor R12, the seventh capacitor C7 and the eighth capacitor C8 are connected together and then connected to the FB pin of the power supply chip U1, the third voltage zener diode Z3 is arranged in parallel at both ends of the seventh capacitor C7 and the eighth capacitor C8, a cathode of the third voltage zener diode Z3 is connected together with the eighth capacitor C8 and then connected to the tenth resistor R10, and an anode of the third voltage zener diode Z3 is connected together with the seventh capacitor C7 and then grounded.

[0029] As a further improvement of the present application, the second power supply unit further includes an indicator element, which is connected to the power supply element and is used to indicate whether the power supply element is started. When the second power supply unit supplies power to the switching unit, the light-emitting diode LED1 in the indicator element is in a light-emitting state;

[0030] The light emitting diode LED1 is connected to the thirteenth resistor R13 and then arranged in parallel at both ends of the seventh capacitor C7 and the eighth capacitor C8, the cathode of the third voltage zener diode Z3 is connected to the thirteenth resistor R13 and then connected to the tenth resistor R10, and the anode of the third voltage zener diode Z3 is connected to the cathode of the light emitting diode LED1 and then grounded.

[0031] As a further improvement of the present application, the switching unit includes a linear regulator LDO, a third diode D3 and a fourth voltage regulator diode Z4;

[0032] The anode of the third diode D3 is used to connect to the working voltage output by the second power supply unit, the cathode of the third diode D3 is used to connect to the VIN pin of the linear regulator LDO, the stabilizing voltage output by the first power supply unit is connected between the cathode of the third diode D3 and the VIN pin of the linear regulator LDO, and a ninth capacitor C9 is further provided between the VIN pin of the linear regulator LDO and the third diode D3, one end of the ninth capacitor C9 is grounded, and the other end of the ninth capacitor C9 is connected between the VIN pin of the linear regulator LDO and the third diode D3;

[0033] The GND pin of the linear regulator LDO is grounded, the VOUT pin of the linear regulator LDO and the cathode of the fourth voltage regulator diode Z4 are connected together and then connected to the main controller, and the anode of the fourth voltage regulator diode Z4 is grounded;

[0034] A tenth capacitor C10 is also connected between the VOUT pin of the linear regulator LDO and the fourth zener diode Z4, and an eleventh capacitor C11 is arranged in parallel at both ends of the tenth capacitor C10, one end of the tenth capacitor C10 and the eleventh capacitor C11 are connected together and then grounded, and the other end of the tenth capacitor C10 and the eleventh capacitor C11 are connected together and then connected between the VOUT pin of the linear regulator LDO and the fourth zener diode Z4.

[0035] As a further improvement of the present application, when the external power supply is disconnected, the linear regulator LDO is powered by the stabilizing voltage, and then the linear regulator LDO is powered to the main controller;

[0036] When the external power supply is connected, since the working voltage is greater than the stabilizing voltage, the working voltage is switched to power the linear regulator LDO, and the second power supply unit powers the main controller and the circuit load.

[0037] Based on the above power supply state switching circuit, the present application also provides a smart cabinet, which includes the power supply state switching circuit described in any one of the above items.

[0038] The power supply state switching circuit and smart cabinet provided in the embodiments of the present application connect the first power supply unit to the power supply battery and the second power supply unit to the external power supply. When the external power supply is disconnected or an accident occurs, the power supply is switched to the power supply battery to supply power only to the main controller to meet the minimum power consumption requirement of the current circuit. When the external power supply is restored, the power supply is switched to the external energy source to supply power to the main controller and other loads in the circuit at the same time, avoiding excessive loss and waste of battery energy. Corresponding step-down circuits and voltage regulator diodes are provided in the first power supply unit and the second power supply unit, which can output a stable voltage for power supply under the premise of wide voltage input. By replacing the first voltage regulator diode with different parameter specifications, the first power supply unit can also output different stabilizing voltages, which is highly flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 is a module diagram of a power supply state switching circuit provided in an embodiment of the present application;

[0041] Figure 2 is a circuit diagram of a first power supply unit in a power supply state switching circuit provided in an embodiment of the present application;

[0042] Figure 3 is a module diagram of a first power supply unit in a power supply state switching circuit provided in an embodiment of the present application;

[0043] Figure 4 is a circuit diagram of a second power supply unit in a power supply state switching circuit provided in an embodiment of the present application;

[0044] Figure 5 is a module diagram of a second power supply unit in a power supply state switching circuit provided in an embodiment of the present application;

[0045] Figure 6It is a circuit diagram of a switching unit in a power supply state switching circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] In the description of the present application, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise clearly and specifically limited. All directional indications in the embodiments of the present application (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions.

[0048] In order to make the description of the disclosed content more detailed and complete, the following is an illustrative description of the implementation methods and specific embodiments of the present application; however, this is not the only form of implementing or using the specific embodiments of the present application. The implementation methods cover the features of multiple specific embodiments and the method steps and sequences used to construct and operate these specific embodiments. However, other specific embodiments can also be used to achieve the same or equivalent functions and step sequences.

[0049] Please refer to Figure 1-Figure 6 In order to solve the problem of how to make the battery pack perform low-power supply during power supply, and how to achieve the state switching between normal power supply and low-power supply, the embodiment of the present application provides a power supply state switching circuit and a smart cabinet. Please refer to Figure 1 , is a functional module diagram of a power supply state switching circuit provided in an embodiment of the present application. The power supply state switching circuit provided in the present application includes a first power supply unit, a second power supply unit and a switching unit.

[0050] As an optional embodiment, the above-mentioned first power supply unit is connected to the power supply battery, used to step down the initial voltage provided by the power supply battery, and output the stabilizing voltage obtained after the step-down to the switching unit, and the second power supply unit is connected to the external power supply, used to step down the voltage of the external power supply to the working voltage, and output the working voltage to the switching unit.

[0051] Furthermore, the switching unit is used to receive a stabilization voltage and an operating voltage. When the external power supply is disconnected, the first power supply unit powers the main controller. When the external power supply is connected, the second power supply unit is switched to power the main controller and the circuit load. The operating voltage is greater than the stabilization voltage.

[0052] In a specific embodiment provided in the present application, the power supply battery is a battery pack, and the external voltage is a grid voltage. When a power outage occurs and the grid voltage cannot provide normal power supply, the battery pack provides low-power power supply and only supplies power to the main controller in the circuit to maintain minimum power consumption. When the grid voltage is providing power normally, the power supply battery stops supplying power, and the main controller and other loads in the circuit are powered by the grid voltage, thereby achieving low-power power supply for the circuit in the event of a power outage and achieving normal functional operation of the circuit in the normal power supply state, thereby avoiding the situation where the battery pack still supplies power to loads that do not need to be operated at the current moment after a power outage, causing energy waste.

[0053] As an optional implementation, please refer to Figure 3 , which is a module diagram of the first power supply unit in the power supply state switching circuit provided in an embodiment of the present application. The first power supply unit provided in the present application includes a voltage stabilizing element, a filtering current limiting element and a first voltage reducing element.

[0054] Among them, the voltage stabilizing element is connected to the power supply battery, and is used to stabilize the initial voltage provided by the power supply battery. The filtering and current limiting element is connected to the voltage stabilizing element, and is used to filter out the high-frequency ripple in the initial voltage provided by the power supply battery. The first voltage reducing element is connected to the filtering and current limiting element, and is used to reduce the initial voltage after filtering the high-frequency ripple, and output the stabilizing voltage obtained after the voltage reduction to the switching unit.

[0055] As an optional embodiment, the first power supply unit provided in the present application also includes a current limiting protection element and an overvoltage protection element. The current limiting protection element is set to provide current limiting protection to the first power supply unit, and the overvoltage protection element is set to absorb the part of the circuit that exceeds the stabilization voltage to provide overvoltage protection to the first power supply unit.

[0056] Please refer to Figure 2 , which is a circuit diagram of the first power supply unit in the power supply state switching circuit provided in an embodiment of the present application. It can be observed that the above-mentioned voltage stabilizing element includes a first diode D1, a first capacitor C1 and a first transient suppression diode TVS1, the filtering and current limiting element includes a second capacitor C2, a third capacitor C3 and a first resistor R1, and the first voltage reducing element includes a first voltage stabilizing diode Z1, a first transistor Q1 and a second transistor Q2.

[0057] Specifically, the anode of the first diode D1 is connected to the power supply battery, the cathode of the first diode D1 is connected to the first capacitor C1, the two ends of the first capacitor C1 are connected in parallel with a first transient suppression diode TVS1, the anode of the first transient suppression diode TVS1 is connected to the first capacitor C1 and then grounded, the cathode of the first transient suppression diode TVS1 is connected to the first capacitor C1 and then connected to the second capacitor C2, the two ends of the second capacitor C2 are connected in parallel with a first resistor R1 and a third capacitor C3, one end of the third capacitor C3 is connected to the second capacitor C2 and then grounded, the two ends of the third capacitor C3 are connected in parallel with a first voltage regulator diode Z1, the other end of the third capacitor C3 is connected to the cathode of the first resistor and the first voltage regulator diode Z1 and then connected to the base of the first transistor Q1.

[0058] Furthermore, the collector of the first transistor Q1 is connected to the second resistor R2, the other end of the second resistor R2 is connected between the first resistor R1 and the second capacitor C2, the emitter of the first transistor Q1 is connected to the base of the second transistor Q2, the collector of the second transistor Q2 is connected to the second resistor R2 and then connected between the first capacitor C1 and the first transient suppression diode TVS1, the emitter of the second transistor Q2 is connected to the second diode D2, the anode of the second diode D2 is connected to the emitter of the second transistor Q2, and the anode of the second diode D2 is connected to the switching unit to output the stabilizing voltage obtained after the voltage reduction to the switching unit.

[0059] It should be noted that the above-mentioned first diode D1 is preferably set to the form of a Schottky diode. During the power supply process of the power supply battery, the battery current B+ of the power supply battery enters the first capacitor C1 and the first transient suppression diode TVS1 through the first diode D1. The first capacitor C1 plays a role in stabilizing the voltage, and the first transient suppression diode TVS1 plays a role in absorbing the peak voltage. The battery current continues to pass through the filtering and current limiting part composed of the second capacitor C2, the first resistor R1 and the third capacitor C3. The high-frequency ripple is filtered out by the second capacitor C2 and the third capacitor C3, and the current is limited by the first resistor R1. After the battery current passes through the first voltage regulator diode Z1, the voltage across the first voltage regulator diode Z1 tends to be stable, and then further passes through the first transistor Q1 and the second transistor Q2 to form a stable stabilizing voltage output to the switching unit.

[0060] In a specific embodiment provided in the present application, after the battery current passes through the first voltage stabilizing diode Z1, the voltage across the first voltage stabilizing diode Z1 is stabilized at 13V. After the first transistor Q1 and the second transistor Q2 are turned on, the voltage drop of the first transistor Q1, the second transistor Q2 and the second diode D2 is estimated to be 0.7V, so the stabilizing voltage output to the switching unit is approximately 12.3V.

[0061] As an optional implementation, the present application further connects a third capacitor C3 between the anode of the second diode D2 and the switching unit, and a second voltage zener diode Z2 is arranged in parallel at both ends of the third capacitor C3. The anode of the second voltage zener diode Z2 and the third capacitor C3 are connected together and then grounded. The cathode of the second voltage zener diode Z2 and the third capacitor C3 are connected together and then connected between the anode of the second diode D2 and the switching unit. The second voltage zener diode Z2 is used to protect the subsequent circuit and absorb part of the voltage that exceeds the stabilization voltage. The third capacitor C3 is a small-capacity energy storage capacitor, which is used to ensure small current output and avoid excessive voltage fluctuations in the circuit.

[0062] For further information, please refer to Figure 2 and Figure 3 It can be observed that the current limiting protection element provided in the present application includes a third resistor R3 and a fourth resistor R4, and the overvoltage protection element includes a third capacitor C3 and a second voltage stabilizing diode Z2.

[0063] Specifically, a third resistor R3 is also connected between the collector of the second transistor Q2 and the collector of the first transistor Q1. The third resistor R3 and the second resistor R2 are connected together and then connected between the first capacitor C1 and the first transient suppression diode TVS1. A fourth resistor R4 is arranged in parallel at both ends of the third resistor R3. Current limiting protection is achieved by the third resistor R3 and the fourth resistor R4 to limit large current output.

[0064] In a specific embodiment provided in the present application, the voltage range provided by the battery pack is 32V-58.4V, the output stabilization voltage is 12.3V, the second resistor R2 is set to 2KΩ, and the resistance values ​​of the third resistor R3 and the fourth resistor R4 are both set to 1KΩ. According to the conversion relationship from the above-mentioned battery voltage output to the stabilization voltage, it is rare to find a linear voltage regulator that realizes this conversion relationship in the prior art; of course, a larger input width can be achieved by selecting a transistor with a larger withstand voltage value. The present application does not impose too many restrictions on the selection of the above-mentioned transistors and the resistance values ​​of the resistors.

[0065] As an optional implementation, please refer to Figure 5 , which is a module diagram of the second power supply unit in the power supply state switching circuit provided in an embodiment of the present application. The second power supply unit provided in the present application includes a power supply element, a second step-down element and an output protection element.

[0066] Specifically, the above-mentioned power supply element is connected to an external power supply, and is turned on when the external power supply is greater than the starting power supply of the power supply element, so that the second step-down element steps down the voltage of the external power supply to the working voltage, and the output protection element is used to absorb the part that exceeds the working voltage to stabilize the voltage output by the second power supply unit to the working voltage.

[0067] Furthermore, the second power supply unit provided in the present application also includes an indicator element, which is connected to the power supply element and is used to indicate whether the power supply element is started. When the second power supply unit supplies power to the switching unit, the light-emitting diode LED1 in the indicator element is in a light-emitting state.

[0068] For details, please refer to Figure 4 , which is a circuit diagram of the second power supply unit in the power supply state switching circuit provided in an embodiment of the present application. The power supply element provided in the present application includes a power supply chip U1, a third transistor Q3, a fourth transistor Q4, a fourth capacitor C4 and a first electrolytic capacitor CD1, the second step-down element includes a first inductor L1 and a second diode D2, and the output protection element includes a third voltage regulator diode Z3.

[0069] Specifically, the base of the third triode Q3 is connected to the external power supply through the fifth resistor R5, and a sixth resistor R6 is connected between the emitter of the third triode Q3 and the base of the third triode Q3, one end of the sixth resistor R6 is connected to the fifth resistor R5 and then connected to the base of the third triode Q3, and the other end of the sixth resistor R6 is connected to the emitter of the third triode Q3 and then grounded.

[0070] Furthermore, a seventh resistor R7 is connected between the collector of the third transistor Q3 and the base of the fourth transistor Q4, an eighth resistor R8 is connected between the emitter of the fourth transistor Q4 and the base of the fourth transistor Q4, and the collector of the fourth transistor Q4 is connected to the VIN pin of the power supply chip U1; the positive electrode of the first electrolytic capacitor CD1 and the fourth capacitor C4 are both connected between the collector of the fourth transistor Q4 and the VIN pin of the power supply chip U1, the negative electrode of the first electrolytic capacitor CD1 and the fourth capacitor C4 are connected to the ground, and the second transient suppression diode TVS2 is connected in parallel at both ends of the fourth capacitor C4.

[0071] Please continue to refer to Figure 3 A fifth capacitor C5 is connected between the VIN pin of the power supply chip U1 and the VC pin of the power supply chip U1. The SW pin of the power supply chip U1 and the EP pin of the power supply chip U1 are connected together and then sequentially connected to the first inductor L1, the ninth resistor R9 and the tenth resistor R10. One end of the tenth resistor R10 is connected to the switching unit to output the working voltage obtained after voltage reduction to the switching unit. A second diode D2 is also connected between the SW pin of the power supply chip U1 and the first inductor L1. The cathode of the second diode D2 is connected between the SW pin of the power supply chip U1 and the first inductor L1, and the anode of the second diode D2 is grounded.

[0072] In an embodiment of the present application, when the grid voltage is used for power supply, EN_12.5V is at a high level, the corresponding third capacitor Q3 and the fourth capacitor Q4 are turned on in sequence, the power supply chip U1 is powered on and started, and at the same time, a BUCK (Buck circuit, step-down conversion) circuit is formed between the power supply chip U1, the inductor L1 and the second diode D2, thereby stepping down the grid voltage and outputting the working voltage obtained after the step-down to the switching unit; in a specific embodiment provided in the present application, the working voltage obtained after the step-down is 12.5V.

[0073] Furthermore, the present application also connects a second electrolytic capacitor CD2 between the ninth resistor R9 and the tenth resistor R10. The positive electrode of the second electrolytic capacitor CD2 is connected to the ninth resistor R9 and then connected to the CSN pin of the power supply chip U1. The CSP pin of the power supply chip U1 is connected between the first inductor L1 and the ninth resistor R9.

[0074] It can be observed that a sixth capacitor C6 is arranged in parallel at both ends of the second electrolytic capacitor CD2, an eleventh resistor R11 and a twelfth resistor R12 are arranged in parallel at both ends of the sixth capacitor C6, the FB pin of the power supply chip U1 is connected between the eleventh resistor R11 and the twelfth resistor R12, a seventh capacitor C7 is arranged in parallel at both ends of the eleventh resistor R11, an eighth capacitor C8 is arranged in parallel at both ends of the twelfth resistor R12, the seventh capacitor C7 and the eighth capacitor C8 are connected together and then connected to the FB pin of the power supply chip U1, a third voltage zener diode Z3 is arranged in parallel at both ends of the seventh capacitor C7 and the eighth capacitor C8, a cathode of the third voltage zener diode Z3 is connected together with the eighth capacitor C8 and then connected to the tenth resistor R10, and an anode of the third voltage zener diode Z3 is connected together with the seventh capacitor C7 and then grounded.

[0075] When setting the light emitting diode LED1, the light emitting diode LED1 can be connected to the thirteenth resistor R13 and then set in parallel at both ends of the seventh capacitor C7 and the eighth capacitor C8, the cathode of the third voltage zener diode Z3 is connected to the thirteenth resistor R13 and then connected to the tenth resistor R10, and the anode of the third voltage zener diode Z3 is connected to the cathode of the light emitting diode LED1 and then grounded.

[0076] In an embodiment of the present application, when the second power supply unit is connected to an external power supply, the second power supply unit supplies power to the switching unit, and the light-emitting diode LED1 is in a light-emitting state, which can intuitively display whether the power is supplied by the second power supply unit. At the same time, when the output voltage is greater than the working voltage, the third voltage regulator diode Z3 stabilizes the voltage at the working voltage for output.

[0077] As an optional implementation, please refer to Figure 6, is a circuit diagram of a switching unit in a power supply state switching circuit provided in an embodiment of the present application. The switching unit provided in the present application includes a linear regulator LDO, a third diode D3 and a fourth voltage regulator diode Z4.

[0078] Among them, the anode of the third diode D3 is used to connect to the working voltage output by the second power supply unit, the cathode of the third diode D3 is used to connect to the VIN pin of the linear regulator LDO, the stabilizing voltage output by the first power supply unit is connected between the cathode of the third diode D3 and the VIN pin of the linear regulator LDO, and a ninth capacitor C9 is also arranged between the VIN pin of the linear regulator LDO and the third diode D3, one end of the ninth capacitor C9 is grounded, and the other end of the ninth capacitor C9 is connected between the VIN pin of the linear regulator LDO and the third diode D3.

[0079] Furthermore, the GND pin of the linear regulator LDO is grounded, the VOUT pin of the linear regulator LDO and the cathode of the fourth zener diode Z4 are connected together and then connected to the main controller, and the anode of the fourth zener diode Z4 is grounded; a tenth capacitor C10 is also connected between the VOUT pin of the linear regulator LDO and the fourth zener diode Z4, an eleventh capacitor C11 is arranged in parallel at both ends of the tenth capacitor C10, one end of the tenth capacitor C10 and the eleventh capacitor C11 are connected together and then grounded, and the other end of the tenth capacitor C10 and the eleventh capacitor C11 are connected together and then connected between the VOUT pin of the linear regulator LDO and the fourth zener diode Z4.

[0080] When the external power supply is disconnected, the linear regulator LDO is powered by the stabilizing voltage, and then the linear regulator LDO supplies power to the main controller; when the external power supply is connected, since the working voltage is greater than the stabilizing voltage, the working voltage is switched to power the linear regulator LDO, and the main controller and the circuit load are powered by the second power supply unit.

[0081] It should be noted that the actual selection of all components used in the above-mentioned power supply state switching circuit of the present application is preferably greater than 25% of the rated value to avoid unexpected situations in the battery. The above-mentioned transistors are preferably set to low leakage current to avoid loss of excess energy.

[0082] In a specific embodiment provided in the present application, the above-mentioned stabilizing voltage is 12.3V, the working voltage is 12.5V, and when the grid voltage is cut off, the battery is used for power supply. Figure 4In the circuit, 12.3V is used to power the linear regulator LDO, and the linear regulator LDO outputs 3.3V_MCU to power the main controller to maintain the minimum power consumption in the circuit; when the grid voltage is restored, since the working voltage 12.5V is greater than the stabilization voltage 12.3V, the working voltage 12.5V is used to power the linear regulator LDO to further power the main controller. Since the second power supply unit is directly connected to the circuit load, the circuit load will be directly powered when the power supply is restored. When the external power supply is connected, the second power supply unit powers the main controller and the circuit load. When the external power supply is disconnected, the first power supply unit only powers the main controller to meet the minimum power consumption of the circuit. Under the premise of wide voltage input, the switching between normal power supply and low power state power supply is realized.

[0083] Based on the above-mentioned power supply status switching circuit, the present application also provides a smart cabinet, which is equipped with the above-mentioned power supply status switching circuit. For other details about the smart cabinet implementing the above-mentioned technical solution, please refer to the description of the power supply status switching circuit and the cabinet door provided in the above-mentioned application embodiment, which will not be repeated here.

[0084] The power supply state switching circuit and smart cabinet provided in the embodiments of the present application connect the first power supply unit to the power supply battery and the second power supply unit to the external power supply. When the external power supply is disconnected or an accident occurs, the power supply is switched to the power supply battery to supply power only to the main controller to meet the minimum power consumption requirement of the current circuit. When the external power supply is restored, the power supply is switched to the external energy source to supply power to the main controller and other loads in the circuit at the same time, avoiding excessive loss and waste of battery energy. Corresponding step-down circuits and voltage regulator diodes are provided in the first power supply unit and the second power supply unit, which can output a stable voltage for power supply under the premise of wide voltage input. By replacing the first voltage regulator diode with different parameter specifications, the first power supply unit can also output different stabilizing voltages, which is highly flexible.

[0085] It can be understood that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above embodiments are merely exemplary embodiments used to illustrate the principles of the present application, but the present application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of the present application, and these modifications and improvements are also considered to be within the scope of protection of the present application.

Claims

1. A power supply state switching circuit, characterized in that: It includes a first power supply unit, a second power supply unit and a switching unit; The first power supply unit is connected to the power supply battery, and is used to step down the initial voltage provided by the power supply battery, and output the stabilizing voltage obtained after the step-down to the switching unit; The second power supply unit is connected to an external power supply, and is used to step down the voltage of the external power supply to an operating voltage, and output the operating voltage to the switching unit; The switching unit is used to receive the stabilization voltage and the working voltage. When the external power supply is disconnected, the first power supply unit supplies power to the main controller. When the external power supply is connected, the second power supply unit is switched to supply power to the main controller and the circuit load; wherein the working voltage is greater than the stabilization voltage.

2. The power supply state switching circuit according to claim 1, characterized in that: The first power supply unit includes a voltage stabilizing element, a filtering and current limiting element, and a first voltage reducing element; The voltage stabilizing element is connected to the power supply battery and is used to stabilize the initial voltage provided by the power supply battery; The filtering and current limiting element is connected to the voltage stabilizing element and is used to filter out high-frequency ripples in the initial voltage provided by the power supply battery; The first voltage-reducing element is connected to the filtering and current-limiting element, and is used to reduce the initial voltage after filtering the high-frequency ripple, and output the stabilizing voltage obtained after the reduction to the switching unit.

3. The power supply state switching circuit according to claim 2, characterized in that: The voltage stabilizing element includes a first diode D1, a first capacitor C1 and a first transient suppression diode TVS1, the anode of the first diode D1 is connected to the power supply battery, the cathode of the first diode D1 is connected to the first capacitor C1, the first transient suppression diode TVS1 is arranged in parallel at both ends of the first capacitor C1, and the anode of the first transient suppression diode TVS1 is connected to the first capacitor C1 and then grounded; The filtering and current-limiting element comprises a second capacitor C2, a third capacitor C3 and a first resistor R1, the cathode of the first transient suppression diode TVS1 is connected to the first capacitor C1 and then connected to the second capacitor C2, the first resistor R1 and the third capacitor C3 are arranged in parallel at both ends of the second capacitor C2, and one end of the third capacitor C3 is connected to the second capacitor C2 and then grounded; The first voltage-reducing element includes a first voltage-stabilizing diode Z1, a first transistor Q1, and a second transistor Q2. The first voltage-stabilizing diode Z1 is arranged in parallel at both ends of the third capacitor C3. The other end of the third capacitor C3 is connected to the cathode of the first voltage-stabilizing diode Z1 and then connected to the base of the first transistor Q1. The collector of the first transistor Q1 is connected to a second resistor R2. The other end of the second resistor R2 is connected between the first resistor R1 and the second capacitor C2. The emitter of the first transistor Q1 is connected to the base of the second transistor Q2. The collector of the second transistor Q2 is connected to the second resistor R2 and then connected between the first capacitor C1 and the first transient suppression diode TVS1. The emitter of the second transistor Q2 is connected to a second diode D2. The anode of the second diode D2 is connected to the emitter of the second transistor Q2. The anode of the second diode D2 is connected to the switching unit to output the stabilizing voltage obtained after voltage reduction to the switching unit.

4. The power supply state switching circuit according to claim 3, characterized in that: The first power supply unit also includes a current limiting protection element and an overvoltage protection element; The current limiting protection element is used to provide current limiting protection for the first power supply unit, and the current limiting protection element includes a third resistor R3 and a fourth resistor R4, the third resistor R3 is arranged between the collector of the second transistor Q2 and the second resistor R2, the third resistor R3 and the second resistor R2 are connected together and then connected between the first capacitor C1 and the first transient suppression diode TVS1, and the fourth resistor R4 is arranged in parallel at both ends of the third resistor R3; The overvoltage protection element is used to absorb the part that exceeds the stabilizing voltage to provide overvoltage protection for the first power supply unit. The overvoltage protection element includes a third capacitor C3 and a second Zener diode Z2. The second Zener diode Z2 is arranged in parallel at both ends of the third capacitor C3. The anode of the second Zener diode Z2 is connected to one end of the third capacitor C3 and then grounded. The cathode of the second Zener diode Z2 is connected to the other end of the third capacitor C3 and then connected between the anode of the second diode D2 and the switching unit.

5. The power supply state switching circuit according to claim 1, characterized in that: The second power supply unit includes a power supply element, a second voltage reduction element and an output protection element; The power supply element is connected to an external power supply, and is turned on when the external power supply is greater than the starting power supply of the power supply element, so that the second voltage-reducing element reduces the voltage of the external power supply to the working voltage; The output protection element is used to absorb a portion exceeding the operating voltage to stabilize the voltage output by the second power supply unit to the operating voltage.

6. The power supply state switching circuit according to claim 5, characterized in that: The power supply element includes a power supply chip U1, a third transistor Q3, a fourth transistor Q4, a fourth capacitor C4 and a first electrolytic capacitor CD1; The base of the third triode Q3 is connected to an external power supply through a fifth resistor R5, a sixth resistor R6 is connected between the emitter of the third triode Q3 and the base of the third triode Q3, one end of the sixth resistor R6 is connected to the base of the third triode Q3 after being connected to the fifth resistor R5, and the other end of the sixth resistor R6 is connected to the emitter of the third triode Q3 after being grounded; A seventh resistor R7 is connected between the collector of the third transistor Q3 and the base of the fourth transistor Q4, an eighth resistor R8 is connected between the emitter of the fourth transistor Q4 and the base of the fourth transistor Q4, and the collector of the fourth transistor Q4 is connected to the VIN pin of the power supply chip U1; the positive electrode of the first electrolytic capacitor CD1 and the fourth capacitor C4 are both connected between the collector of the fourth transistor Q4 and the VIN pin of the power supply chip U1, the negative electrode of the first electrolytic capacitor CD1 and the fourth capacitor C4 are connected to ground after being connected in common, a second transient suppression diode TVS2 is connected in parallel at both ends of the fourth capacitor C4, and a fifth capacitor C5 is connected between the VIN pin of the power supply chip U1 and the VC pin of the power supply chip U1; The second voltage-reducing element includes a first inductor L1 and a second diode D2. The SW pin of the power supply chip U1 and the EP pin of the power supply chip U1 are connected to the first inductor L1. The first inductor L1 is connected to the switching unit through a ninth resistor R9 and a tenth resistor R10 to output the working voltage obtained after voltage reduction to the switching unit. The cathode of the second diode D2 is connected between the SW pin of the power supply chip U1 and the first inductor L1, and the anode of the second diode D2 is grounded. The output protection element includes a third voltage stabilizing diode Z3, a second electrolytic capacitor CD2 is further connected between the ninth resistor R9 and the tenth resistor R10, a positive electrode of the second electrolytic capacitor CD2 is connected to the ninth resistor R9 and then connected to the CSN pin of the power supply chip U1, and the CSP pin of the power supply chip U1 is connected between the first inductor L1 and the ninth resistor R9; A sixth capacitor C6 is arranged in parallel at both ends of the second electrolytic capacitor CD2, an eleventh resistor R11 and a twelfth resistor R12 are arranged in parallel at both ends of the sixth capacitor C6, an FB pin of the power supply chip U1 is connected between the eleventh resistor R11 and the twelfth resistor R12, a seventh capacitor C7 is arranged in parallel at both ends of the eleventh resistor R11, an eighth capacitor C8 is arranged in parallel at both ends of the twelfth resistor R12, the seventh capacitor C7 and the eighth capacitor C8 are connected together and then connected to the FB pin of the power supply chip U1, the third voltage zener diode Z3 is arranged in parallel at both ends of the seventh capacitor C7 and the eighth capacitor C8, a cathode of the third voltage zener diode Z3 is connected together with the eighth capacitor C8 and then connected to the tenth resistor R10, and an anode of the third voltage zener diode Z3 is connected together with the seventh capacitor C7 and then grounded.

7. The power supply state switching circuit according to claim 6, characterized in that: The second power supply unit further includes an indicator element, which is connected to the power supply element and is used to indicate whether the power supply element is started. When the second power supply unit supplies power to the switching unit, the light emitting diode LED1 in the indicator element is in a light emitting state; The light emitting diode LED1 is connected to the thirteenth resistor R13 and then arranged in parallel at both ends of the seventh capacitor C7 and the eighth capacitor C8, the cathode of the third voltage zener diode Z3 is connected to the thirteenth resistor R13 and then connected to the tenth resistor R10, and the anode of the third voltage zener diode Z3 is connected to the cathode of the light emitting diode LED1 and then grounded.

8. The power supply state switching circuit according to claim 1, characterized in that: The switching unit includes a linear regulator LDO, a third diode D3 and a fourth voltage regulator diode Z4; The anode of the third diode D3 is used to connect to the working voltage output by the second power supply unit, the cathode of the third diode D3 is used to connect to the VIN pin of the linear regulator LDO, the stabilizing voltage output by the first power supply unit is connected between the cathode of the third diode D3 and the VIN pin of the linear regulator LDO, and a ninth capacitor C9 is further provided between the VIN pin of the linear regulator LDO and the third diode D3, one end of the ninth capacitor C9 is grounded, and the other end of the ninth capacitor C9 is connected between the VIN pin of the linear regulator LDO and the third diode D3; The GND pin of the linear regulator LDO is grounded, the VOUT pin of the linear regulator LDO and the cathode of the fourth voltage regulator diode Z4 are connected together and then connected to the main controller, and the anode of the fourth voltage regulator diode Z4 is grounded; A tenth capacitor C10 is also connected between the VOUT pin of the linear regulator LDO and the fourth zener diode Z4, and an eleventh capacitor C11 is arranged in parallel at both ends of the tenth capacitor C10, one end of the tenth capacitor C10 and the eleventh capacitor C11 are connected together and then grounded, and the other end of the tenth capacitor C10 and the eleventh capacitor C11 are connected together and then connected between the VOUT pin of the linear regulator LDO and the fourth zener diode Z4.

9. The power supply state switching circuit according to claim 8, characterized in that: When the external power supply is disconnected, the linear voltage regulator LDO is powered by the stabilizing voltage, and then the linear voltage regulator LDO is powered by the main controller; When the external power supply is connected, since the working voltage is greater than the stabilizing voltage, the working voltage is switched to power the linear regulator LDO, and the second power supply unit powers the main controller and the circuit load.

10. A smart cabinet, characterized in that: The smart cabinet includes the power supply state switching circuit as described in any one of claims 1-9.

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