Backup power switching circuit and apparatus

Abstract

The utility model discloses a kind of backup power supply switching circuit and device, including voltage detection unit;One end of the voltage detection unit is electrically connected with battery, and the other end of the voltage detection unit is electrically connected with load through first diode;The voltage detection unit is also electrically connected with commercial power through power conversion module;Commercial power is electrically connected with load in turn through power conversion module, second diode.The application also proposes a kind of backup power supply switching device, including the circuit as described in the above embodiment.It is beneficial to effect: the present application adopts pure hardware switching mechanism, saves software judgment and control time, voltage detection and switch response are completed in microsecond level, effectively avoid commercial power outage when power supply interruption, improve system running continuity.

Description

Technical Field

[0001] This utility model relates to the field of power switching, and in particular to a backup power switching circuit and device. Background Technology

[0002] Smart terminal products are equipped with backup power supplies to ensure that the device can continue to be powered after the mains power fails, so as to perform functions such as event reporting and data saving.

[0003] Backup power supplies mostly use rechargeable batteries. The battery life is limited by the number of charge and discharge cycles. Therefore, in order to extend the battery life, the battery output is disconnected when there is mains power to prevent the battery from continuously undergoing charge and discharge cycles. Utility Model Content

[0004] Purpose of the utility model: The purpose of this utility model is to solve the problems in the prior art and provide a backup power switching circuit and device.

[0005] Technical solution: A backup power switching circuit is proposed, including a voltage detection unit; One end of the voltage detection unit is electrically connected to the battery, and the other end of the voltage detection unit is electrically connected to the load through a first diode; The voltage detection unit is also electrically connected to the mains power supply via a power conversion module; The mains power is electrically connected to the load via a power conversion module and a second diode.

[0006] Preferably, the voltage detection unit includes a mains power detection unit and a circuit switching unit; The two ends of the mains power detection unit are electrically connected to the power conversion module and the circuit switching unit, respectively; The circuit switching unit is electrically connected to the battery, the mains power detection unit, and the load, respectively.

[0007] Preferably, the mains power detection unit includes a voltage detection chip, a capacitor, a first resistor, a second resistor, and a third resistor; The power supply terminal of the voltage detection chip is grounded through a capacitor; The power supply terminal of the voltage detection chip is electrically connected to the power conversion module through a first resistor; The power supply terminal of the voltage detection chip is grounded through a second resistor; The grounding terminal of the voltage detection chip is grounded; The output terminal of the voltage detection chip is grounded through a third resistor; The output terminal of the voltage detection chip is electrically connected to the circuit switching unit.

[0008] Preferably, the circuit switching unit includes a PMOS transistor, a transistor, a seventh resistor, a fourth resistor, a fifth resistor, and a sixth resistor; The positive terminal of the battery is electrically connected to the source of the PMOS transistor, the drain of the PMOS transistor is electrically connected to the load, and the drain of the PMOS transistor is grounded through a sixth resistor. The gate of the PMOS transistor is electrically connected to the positive terminal of the battery through a fifth resistor. The gate of the PMOS transistor is electrically connected to the collector of the transistor. The emitter of the transistor is electrically connected to the output terminal of the voltage detection chip; The base of the transistor is grounded through a fourth resistor, and the base of the transistor is connected to the main control chip through a seventh resistor.

[0009] Preferably, the main control chip is electrically connected to the positive terminal of the battery.

[0010] Preferably, the voltage detection chip is model SGM809B.

[0011] Preferably, the power conversion module is an AC-DC voltage conversion module.

[0012] This application also proposes a backup power switching device, including the circuit described in the above embodiments.

[0013] Beneficial effects: This invention adopts a pure hardware switching mechanism, eliminating the time required for software judgment and control. Voltage detection and switching response are completed in microseconds, effectively avoiding power interruption when the mains power fails and improving the continuity of system operation.

[0014] The switching process is smooth with minimal output voltage fluctuations, preventing system crashes caused by sudden voltage drops and thus avoiding data loss and equipment damage.

[0015] The entire switching process does not rely on MCU control, avoiding switching failures caused by software errors or system freezes at critical moments, and significantly reducing the failure rate.

[0016] When the mains power supply is normal, the battery output is disconnected to avoid unnecessary charge and discharge cycles, thereby extending the battery's lifespan.

[0017] The design incorporates sufficient voltage switching redundancy to ensure stable and reliable power supply even under high temperature or component aging conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the mains power detection unit circuit of this utility model; Figure 3This is a circuit diagram of the power conversion module of this utility model; Figure 4 This is a schematic diagram of the mains power change of this utility model.

[0019] Figure label: 1. Power conversion module; 2. Mains power detection unit; 3. Circuit switching unit; 4. Battery; 5. Main control chip; 6. Load. Detailed Implementation

[0020] To make the technical solution of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0021] To make the technical solution of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but does not exclude other elements or objects.

[0023] In response to the problems existing in the current technology, combined with Figure 1-3 A backup power switching circuit includes a voltage detection unit; One end of the voltage detection unit is electrically connected to the battery 4 (BAT), and the other end of the voltage detection unit is electrically connected to the load 6 (VBAT) through the first diode; The voltage detection unit is also electrically connected to the mains power supply through the power conversion module 1; The mains power is electrically connected to the load 6 (VBAT) in sequence through the power conversion module 1 and the second diode.

[0024] In some specific embodiments, the voltage detection unit includes a mains power detection unit 2 and a circuit switching unit 3; The two ends of the mains power detection unit 2 are electrically connected to the power conversion module 1 and the circuit switching unit 3, respectively. The circuit switching unit 3 is electrically connected to the battery 4 (BAT), the mains power detection unit 2, and the load 6 (VBAT), respectively. When mains power is available, the existing charging circuit can charge battery 4 (BAT).

[0025] Specifically, when the mains power is not interrupted, the AC mains power is converted into DC (e.g., 12V) for load 6 (VBAT) through power conversion module 1, and the load 6 (VBAT) is directly powered through the second diode; When the mains power begins to decrease, the converted DC power also begins to decrease. When the threshold set by the mains power detection unit 2 is reached, a signal is sent to the circuit switching unit 3, and the circuit switching unit 3 automatically opens the circuit between the battery 4 (BAT) and the load 6 (VBAT). The first and second diodes prevent the backup power supply from back-feeding into the mains power supply path (or charging module) when the mains power fails; they also prevent backflow and damage to components when both power supplies are turned on simultaneously.

[0026] In some specific embodiments, combined with Figure 2 The mains power detection unit 2 includes a voltage detection chip U1, a capacitor C1, a first resistor R1, a second resistor R2, and a third resistor R3; The power supply terminal VCC of the voltage detection chip U1 is grounded through capacitor C1; The power supply terminal VCC of the voltage detection chip U1 is electrically connected to the power conversion module 1 through the first resistor R1; The power supply terminal VCC of the voltage detection chip U1 is grounded through the second resistor R2; The grounding terminal GND of the voltage detection chip U1 is grounded; The output terminal RST of the voltage detection chip U1 is grounded through the third resistor R3; The output terminal RST of the voltage detection chip U1 is electrically connected to the circuit switching unit 3.

[0027] Specifically, +12V_ACDC is the AC power that is converted to 12V to supply power to the system through the power conversion module 1. When the AC power fails, the voltage will change from 12V to 0V. Based on the detection threshold of the preset AC power detection unit 2, such as 2.93V, when the voltage of the power supply terminal VCC is higher than 2.93V, the output terminal RST outputs a high level to the circuit switching unit 3, and when the voltage of the power supply terminal VCC is higher than 2.93V, the output terminal RST outputs a low level to the circuit switching unit 3. In addition, the voltage input at the power supply terminal VCC can be adjusted as needed using the first resistor R1 and the second resistor R2. For example, by adjusting the first resistor R1 and the second resistor R2, when +12V_ACDC is at 9V, the VCC input is 2.93V, and the output terminal RST level switches at 8V.

[0028] In some specific embodiments, when the system mains power fails, the +12V_ACDC will undergo a curve-like decline process. When the voltage drops to 9V, the output terminal RST pin of the voltage detection chip U1 will change from high to low.

[0029] It should be noted that, in order to ensure the stability and reliability of the power switching process, this invention designs a switching redundancy time, which is an effective buffer time between the mains power failure and the completion of the backup power switching. In theory, when the +12V_ACDC voltage is lower than 9V, the hardware switching circuit can complete the switching in microseconds. However, considering that factors such as ambient temperature and device aging may cause response delays, this application sets up a redundant window to ensure stable system operation. Actual testing verified that during the process of the mains voltage dropping from 9V to 6V, the backend can still provide stable power to the load 6 (VBAT) system for up to 20ms, which fully meets the time requirements for hardware detection, signal conversion and switching response, ensuring that the system does not stop running during power failure.

[0030] In some specific embodiments, combined with Figure 3 The circuit switching unit 3 includes a PMOS transistor Q1, a transistor Q5, a seventh resistor R28, a fourth resistor R16, a fifth resistor R96, and a sixth resistor R33. The positive terminal of the battery 4 (BAT) is electrically connected to the source of the PMOS transistor Q1, the drain of the PMOS transistor Q1 is electrically connected to the load 6 (VBAT), and the drain of the PMOS transistor Q1 is grounded through the sixth resistor R33. The gate of the PMOS transistor Q1 is electrically connected to the positive terminal of the battery 4 (BAT) through the fifth resistor R96. The gate of the PMOS transistor Q1 is electrically connected to the collector of the transistor Q5. The emitter of the transistor Q5 is electrically connected to the output terminal RST of the voltage detection chip U1; The base of transistor Q5 is grounded through the fourth resistor R16, and the base of transistor Q5 is connected to the main control chip 5 through the seventh resistor R28.

[0031] In some specific embodiments, the main control chip 5 is electrically connected to the positive terminal of the battery 4 (BAT).

[0032] In some specific embodiments, the voltage detection chip U1 is model SGM809B.

[0033] In some specific embodiments, the power conversion module 1 is an AC-DC voltage conversion module.

[0034] In some embodiments, this application provides a backup power switching device, including the circuit described in the above embodiments.

[0035] In practice, the main control chip 5 starts the switching operation by controlling POWER_CTL_IO to be high in the control diagram. When the main control chip 5 detects that the voltage of the battery 4 (BAT) is too low to supply power to the load 6 (VBAT), it generates POWER_CTL_IO to be low and stops the switching of the entire system. When the voltage detection chip U1 outputs a high level, this high-level signal is connected to the emitter of transistor Q5, and the base is also at a high level. There is no voltage difference between BE, so transistor Q5 does not conduct, resulting in zero leakage current in transistor Q5. The gate of PMOS transistor Q1 is at a high level, so the gate of PMOS transistor Q1 does not conduct. Battery 4 (BAT) will not supply power to load 6 (VBAT), battery 4 (BAT) is disconnected, and the system is powered by AC mains.

[0036] When the mains power is disconnected, the voltage detection chip U1 outputs a low level. This low level signal is connected to the emitter of transistor Q5, while the base remains high. At this time, the base and the emitter turn on transistor Q5, and the gate voltage of PMOS transistor Q1 is pulled low, turning on PMOS transistor Q1. The power supply of battery 4 (BAT) supplies power to the system through PMOS transistor Q1, achieving a smooth switching.

[0037] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A backup power switching circuit, characterized in that, Includes a voltage detection unit; One end of the voltage detection unit is electrically connected to the battery, and the other end of the voltage detection unit is electrically connected to the load through a first diode; The voltage detection unit is also electrically connected to the mains power supply via a power conversion module; The mains power is electrically connected to the load via a power conversion module and a second diode.

2. The backup power switching circuit according to claim 1, characterized in that, The voltage detection unit includes a mains power detection unit and a circuit switching unit; The two ends of the mains power detection unit are electrically connected to the power conversion module and the circuit switching unit, respectively; The circuit switching unit is electrically connected to the battery, the mains power detection unit, and the load, respectively.

3. The backup power switching circuit according to claim 2, characterized in that, The mains power detection unit includes a voltage detection chip, a capacitor, a first resistor, a second resistor, and a third resistor; The power supply terminal of the voltage detection chip is grounded through a capacitor; The power supply terminal of the voltage detection chip is electrically connected to the power conversion module through a first resistor; The power supply terminal of the voltage detection chip is grounded through a second resistor; The grounding terminal of the voltage detection chip is grounded; The output terminal of the voltage detection chip is grounded through a third resistor; The output terminal of the voltage detection chip is electrically connected to the circuit switching unit.

4. A backup power switching circuit according to claim 3, characterized in that, The circuit switching unit includes a PMOS transistor, a transistor, a seventh resistor, a fourth resistor, a fifth resistor, and a sixth resistor; The positive terminal of the battery is electrically connected to the source of the PMOS transistor, the drain of the PMOS transistor is electrically connected to the load, and the drain of the PMOS transistor is grounded through a sixth resistor. The gate of the PMOS transistor is electrically connected to the positive terminal of the battery through a fifth resistor. The gate of the PMOS transistor is electrically connected to the collector of the transistor. The emitter of the transistor is electrically connected to the output terminal of the voltage detection chip; The base of the transistor is grounded through a fourth resistor, and the base of the transistor is connected to the main control chip through a seventh resistor.

5. A backup power switching circuit according to claim 4, characterized in that, The main control chip is electrically connected to the positive terminal of the battery.

6. A backup power switching circuit according to claim 3, characterized in that, The voltage detection chip is model SGM809B.

7. A backup power switching circuit according to claim 1, characterized in that, The power conversion module is an AC-DC voltage conversion module.

8. A backup power switching device, characterized in that, Includes the circuit as described in any one of claims 1-7.

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