Power supply switching protection circuit and device

Abstract

The utility model provides a power supply switching protection circuit and device. In the power supply switching protection circuit, a power supply switch module is respectively connected with a voltage dividing module, a switch control module and a power supply input module, the power supply switch module and the voltage dividing module are used for being connected with a first power supply, and the power supply input module is used for being connected with a second power supply. The power switch module and the power input module are both used for being connected with a load at a first point. Specifically, when the first power supply is powered on, the voltage dividing module is used for dividing a first voltage of the first power supply to obtain a divided voltage, and the power switch module is used for conducting when the divided voltage is greater than a preset voltage to conduct a path from a first point to the first power supply. When the first power supply is powered down, the switch control module is used for outputting a power-down control signal based on a received power-down signal, and the power switch module is used for switching off based on the power-down control signal so as to disconnect a path from the first point to the first power supply. The possibility of current backflow can be reduced.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a power switching protection circuit and device. Background Technology

[0002] There is an ATX (Advanced Technology Extended) power supply on the market that, when connected to a 220V AC mains, can provide two DC power supplies, 12V and 5V, to a DUT (Device Under Test).

[0003] The 12V power supply only outputs 12V DC voltage normally when the DUT is powered on; it has no output when the DUT is powered off or in sleep mode. The 5V power supply, however, outputs 5V DC normally in all DUT states, including powered off, sleep, and powered on.

[0004] Because the DUT needs to switch between states, it will be supplied with both 5V and 12V DC power. There is a risk of backflow during power switching. Utility Model Content

[0005] This application provides a power switching protection circuit and device that can reduce the possibility of current backflow and improve circuit safety.

[0006] In a first aspect, embodiments of this application provide a power switching protection circuit, comprising a power switch module, a voltage divider module, a switch control module, and a power input module. The power switch module is connected to the voltage divider module, the switch control module, and the power input module. Both the power switch module and the voltage divider module are connected to a first power source, and the power input module is connected to a second power source. Both the power switch module and the power input module are connected to a load at a first point. The path from the first power source to the first point via the power switch module is always open, and the path from the second power source to the first point via the power input module is also always open. When the first power source is powered on, the voltage divider module divides the first voltage of the first power source to obtain a divided voltage. The power switch module is turned on when the divided voltage is greater than a preset voltage, thereby opening the path from the first point to the first power source. When the first power source is powered off, the switch control module outputs a power-off control signal based on a received power-off signal, and the power switch module is turned off based on the power-off control signal, thereby disconnecting the path from the first point to the first power source.

[0007] In some embodiments, the power switch module is further configured to turn off when the voltage divider is less than or equal to the preset voltage, thereby cutting off the path from the first point to the first power source.

[0008] In some embodiments, the switch control module includes a switch transistor PQ3 and a resistor PR5. A first terminal of the resistor PR5 is used to receive the power-down signal, and a second terminal of the resistor PR5 is connected to the control of the switch transistor PQ3. A first terminal of the switch transistor PQ3 is connected to the power switch module, and a second terminal of the switch transistor PQ3 is grounded.

[0009] In some embodiments, the power switch module includes a first switch unit and a second switch unit. The first switch unit is connected to the second switch unit, the voltage divider module, and the switch control module, respectively. The second switch unit is also connected to the voltage divider module. The second switch unit is used to connect to the first power supply and to the load and the power input module at the first point. The first switch unit is used to turn on when the voltage divider voltage is greater than a preset voltage and to turn off upon receiving the power-down control signal. The second switch unit is used to turn on when the first switch unit is on to connect the path from the first point to the first power supply; and to turn off when the first switch unit is off to disconnect the path from the first point to the first power supply.

[0010] In some embodiments, the first switching unit includes a switching transistor PQ2 and a resistor PR4. The control terminal of the switching transistor PQ2 is connected to the voltage divider module and the switch control module, respectively. The first terminal of the switching transistor PQ2 is connected to the first terminal of the resistor PR4, the second terminal of the switching transistor PQ2 is grounded, and the second terminal of the resistor PR4 is connected to the power switch module.

[0011] In some embodiments, the second switching unit includes a switching transistor PQ1, a resistor PR3, and a capacitor PC1. A first terminal of the switching transistor PQ1 is connected to the voltage divider module, and the first terminal of the switching transistor PQ1 is used to connect to the first power supply. A second terminal of the switching transistor PQ1 is connected to the first terminal of the resistor PR3, the first terminal of the capacitor PC1, and the power input module, respectively. The second terminal of the switching transistor PQ1 is used to connect to the load. The control terminal of the switching transistor PQ1 is connected to the second terminal of the resistor PR3, the second terminal of the capacitor PC1, and the first switching unit; wherein, the second terminal of the switching transistor PQ1 is the first point.

[0012] In some embodiments, the voltage divider module includes resistors PR1 and PR2. A first terminal of resistor PR1 is connected to the first power supply, a second terminal of resistor PR1 is connected to the first terminal of resistor PR2 and the power switch module, and a second terminal of resistor PR2 is grounded.

[0013] In some embodiments, the power input module includes a diode PD1, a capacitor PC2, and a capacitor PC3. The anode of diode PD1 is connected to the first terminal of capacitor PC2 and the first terminal of capacitor PC3, respectively. The anode of diode PD1 is also used to connect to the second power supply. The cathode of diode PD1 is connected to the power switch module and the cathode of diode PD1 is used to connect to the load. The second terminals of capacitor PC2 and the second terminals of capacitor PC3 are both grounded. The cathode of diode PD1 is the first point.

[0014] In some embodiments, the power switching protection circuit further includes a first interface. The first interface is connected to the power switch module, the voltage divider module, the switch control module, and the power input module, respectively. The first interface is used to connect to the first power supply, to the second power supply, and to receive the power-down control signal.

[0015] Secondly, embodiments of this application also provide a power switching protection device, which includes the power switching protection circuit described above.

[0016] This application provides a power switching protection circuit and device. The power switching protection circuit includes a power switch module, a voltage divider module, a switch control module, and a power input module. The power switch module is connected to the voltage divider module, the switch control module, and the power input module. Both the power switch module and the voltage divider module are used to connect to a first power source, and the power input module is used to connect to a second power source. Both the power switch module and the power input module are used to connect to a load at a first point. The path from the first power source to the first point is always open through the power switch module, and the path from the second power source to the first point is always open through the power input module. When the first power source is powered on, the voltage divider module divides the first voltage of the first power source to obtain a divided voltage. The power switch module is turned on when the divided voltage is greater than a preset voltage, thus opening the path from the first point to the first power source. When the first power source is powered off, the switch control module outputs a power-off control signal based on a received power-off signal, and the power switch module is turned off based on the power-off control signal, thus disconnecting the path from the first point to the first power source. Therefore, by controlling the power switch module to turn on and off in different states of power supply (power on and power off), the path between the first and second power supplies and the load can be switched, ensuring that the load receives power in different power states, thus improving the flexibility and reliability of the power supply. When the first power supply fails, turning off the power switch module effectively prevents the second power supply from supplying power in reverse through the first power supply path, avoiding potential current backflow problems and protecting other components in the circuit and the power supply itself. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a structural block diagram of a power switching protection circuit provided in an embodiment of this application;

[0019] Figure 2 This is a structural block diagram of a power switching protection circuit provided in another embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the circuit structure of a power switching protection circuit provided in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the circuit structure of the first interface provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0023] The technical features involved in the various embodiments of this application described below do not conflict with each other and can be combined with each other.

[0024] When an element is described as "connected" to another element, it can be directly connected to the other element, or there may be one or more intervening elements between them.

[0025] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more.

[0026] One type of power supply currently available on the market is the ATX (Advanced Technology Extended) power supply. An ATX power supply refers to the operating power supply for a computer, its function being to convert AC 220V power into DC 5V, DC 12V, etc., power for internal computer use. When connected to a 220V AC mains, an ATX power supply can provide +12V DC and +5V DC power to the DUT (Device Under Test, specifically referring to the desktop computer being tested in this article).

[0027] Typically, a +12V DC power supply only outputs 12V DC voltage when the DUT is powered on. When the DUT is powered off or in sleep mode, the +12V DC power supply has no output, and its voltage level is 0. However, a +5V DC power supply outputs 5V DC voltage normally in all DUT states, including powered off, sleep, and powered on.

[0028] In summary, during the testing or use of the DUT, when the DUT is in a power-off or sleep state, the +5V DC power supply is required, while the +12V DC power supply is not required; when the DUT is in a power-on state, both the +12V DC power supply and the +5V DC power supply are required.

[0029] Hereinafter, the power-off state and sleep state will be collectively referred to as standby state. The standby state below refers to either the power-off state or the sleep state.

[0030] Therefore, the testing or use of the DUT involves two switching states: the first switching state and the second switching state. The first switching state includes the switching from standby state to power-on state.

[0031] The second type of switching state includes the switching state from power-on state to standby state.

[0032] This application provides a power switching protection circuit and device to assist test equipment in normally performing power-off state, standby state, first switching state and second switching state, and to reduce the possibility of reverse flow between +12V DC power supply and +5V DC power supply, so as to improve the safety and stability of the circuit.

[0033] Please see Figure 1 , Figure 1 This is a structural block diagram of a power switching protection circuit 100 provided in an embodiment of this application.

[0034] This application provides a power switching protection circuit 100, which includes a power switch module 10, a voltage divider module 20, a switch control module 30, and a power input module 40. The power switch module 10 is connected to the voltage divider module 20, the switch control module 30, and the power input module 40. Both the power switch module 10 and the voltage divider module 20 are used to connect to a first power source (…). Figure 1 (Not shown) is connected, and the power input module 40 is used to connect with the second power source ( Figure 1 (Not shown) connection, the power switch module 10 and the power input module 40 are both used to connect with the load ( Figure 1 (Not shown) Connected to point A. The first power supply is always connected to point A via power switch module 10, and the second power supply is always connected to point A via power input module 40. Specifically, when the first power supply is powered on, voltage divider module 20 divides the first voltage of the first power supply to obtain a divided voltage. Power switch module 10 is turned on when the divided voltage is greater than a preset voltage, thus connecting point A to the first power supply. When the first power supply is powered off, switch control module 30 outputs a power-off control signal based on the received power-off signal, and power switch module 10 is turned off based on the power-off control signal, thus disconnecting the path from point A to the first power supply.

[0035] The load refers to the electronic devices that require power. For example, if the power switching protection circuit 100 is applied to a computer host, the load could be components inside the host such as the motherboard, CPU (Central Processing Unit), graphics card, hard drive, and memory. These components work together to complete various functions of the computer, such as data processing, graphics rendering, and data storage, all of which require a stable power supply.

[0036] The first power supply is connected to the power switching protection circuit 100 at a point of +12_SYS. It can be a +12V DC voltage or other suitable voltage values ​​that meet the circuit requirements. It is always open through the power switch module 10 to the first point A.

[0037] The second power supply is connected to the power switching protection circuit 100 at +5V_SB, which can be a +5V DC voltage or other suitable voltage. It is always open through the power input module 40 to the first point A.

[0038] The first voltage refers to the voltage value output by the first power supply, which is the potential difference output by the first power supply under normal operating conditions. It is the input voltage for the voltage divider module 20 to perform voltage divider operation.

[0039] The voltage divider is the voltage obtained by the voltage divider module 20 after dividing the first voltage of the first power supply. The voltage divider module 20 is usually composed of components such as resistors. It uses the voltage dividing principle of resistors to distribute the first voltage according to a certain ratio to obtain a relatively low voltage value. This voltage value is used to control whether the power switch module 10 is turned on or off.

[0040] The preset voltage is a pre-set reference voltage value used for comparison with the voltage divider. When the voltage divider is greater than the preset voltage, the power switch module 10 is turned on, connecting the path from point A to the first power source; conversely, when the voltage divider is less than or equal to the preset voltage, the power switch module 10 is turned off.

[0041] The power failure signal indicates that the first power supply has started to fail; its input point is... Figure 1 The PSON# signal is typically generated by a power monitoring circuit or related detection mechanism to control the switch control module 30 to perform corresponding actions. In some embodiments, the power-down signal may be a high-level signal.

[0042] The power-down control signal is the signal output by the switch control module 30 after receiving a power-down signal. The switch control module 30 processes the power-down signal and then outputs the power-down control signal to the power switch module 10, controlling the power switch module 10 to turn off, thereby disconnecting the path from point A to the first power source and protecting the circuit and load. In some embodiments, the power-down control signal may be a low-level signal.

[0043] In some embodiments, the power switch module 10 is further configured to turn off when the voltage divider is less than or equal to a preset voltage, thereby cutting off the path from the first point A to the first power supply.

[0044] In practical applications, when the DUT (test device) is in standby mode (either power-off or sleep mode), the second power supply ( Figure 1 The power supply is located at +5V_SB, while the first power supply ( Figure 1 The power supply connected at +12_SYS is not supplying power. At this time... Figure 1 A power-down signal (e.g., a high-level signal) is input to the switch control module 30 at PSON#. Simultaneously, the power switch module 10 is also not conducting; this means that the direction from the first power source through the power switch module 10 to the load is not connected.

[0045] When the DUT performs the first switching state, that is, the switching state from standby state to power-on state, the second power supply continues to supply power, and the first power supply is powered on. When the first power supply is powered on, its output first voltage is transmitted to the voltage divider module 20. The voltage divider module 20 reduces the first voltage proportionally to obtain a divided voltage. The power switch module 10 receives the divided voltage from the voltage divider module 20 and compares it with a preset voltage. When the divided voltage is greater than the preset voltage (indicating that the voltage of the first power supply has reached a suitable power supply state), the power switch module 10 is turned on, thereby opening the path from point A to the first power supply. This allows the first power supply to stably supply power to the load.

[0046] When the DUT is powered on, it is powered by both the first and second power supplies.

[0047] When the DUT performs the second switching state, that is, the switching state from the power-on state to the standby state, the second power supply continues to supply power, while the first power supply needs to be powered down. When the first power supply is powered down, the switch control module 30 first outputs a power-down control signal based on the received power-down signal. Subsequently, after receiving the power-down control signal output by the switch control module 30, the power switch module 10 immediately switches from the on state to the off state, thereby disconnecting the path from point A to the first power supply. Then, the first power supply begins to power down. This operation is crucial, as it prevents abnormal situations caused by the power-down of the first power supply (such as reverse current, voltage fluctuations, etc.) from damaging the load and the second power supply, ensuring that the second power supply can continuously and stably supply power to the load, and maintaining the safe and stable operation of the entire circuit system.

[0048] Please see Figure 2 , Figure 2 This is a structural block diagram of a power switching protection circuit 100 provided in another embodiment of this application.

[0049] In some embodiments, the power switching protection circuit 100 further includes a first interface 50. The first interface 50 is connected to the power switch module 10, the voltage divider module 20, the switch control module 30, and the power input module 40, respectively. Specifically, the first interface 50 is used to connect to a first power supply, to a second power supply, and to receive a power-down control signal.

[0050] In some embodiments, the power-down signal can be a high-level signal. This could be the PSON# signal provided by the ATX power supply.

[0051] Normally, the computer's power switch is connected to the power switch pin on the motherboard, and the level of the PSON# signal is controlled by circuitry on the motherboard. When the user presses the computer's power switch, the motherboard pulls the PSON# signal low, thus activating the ATX power supply. When the user presses the power switch again or shuts down the computer via software, the motherboard returns the PSON# signal to a high level, and the ATX power supply enters standby mode, ceasing to supply power to most devices.

[0052] For example, when the voltage at +12V_SYS is less than 10.8V, the voltage at PSON# is set to 3.3V (i.e., the power-down signal); when the voltage at +12V_SYS is greater than 10.8V, the voltage at PSON# is set to 0V (which can be called the power-on signal).

[0053] Please see Figure 3 , Figure 3 This is a schematic diagram of the circuit structure of a power switching protection circuit 100 provided in an embodiment of this application.

[0054] In some embodiments, the switch control module 30 includes a switch transistor PQ3 and a resistor PR5. The first terminal of the resistor PR5 is used to receive a power-down signal, the second terminal of the resistor PR5 is connected to the control of the switch transistor PQ3, the first terminal of the switch transistor PQ3 is connected to the power switch module 10, and the second terminal of the switch transistor PQ3 is grounded.

[0055] In this context, the switching transistor PQ3 can be an NMOS transistor or any other suitable switching transistor. For example, when the switching transistor PQ3 is an NMOS transistor, the control terminal of the switching transistor PQ3 is the gate of the NMOS transistor, the first terminal of the switching transistor PQ3 is the drain of the NMOS transistor, and the second terminal of the switching transistor PQ3 is the source of the NMOS transistor.

[0056] In some embodiments, the power switch module 10 includes a first switch unit 11 and a second switch unit 12. The first switch unit 11 is connected to the second switch unit 12, the voltage divider module 20, and the switch control module 30. The second switch unit 12 is also connected to the voltage divider module 20. The second switch unit 12 is used to connect to a first power source and to a load and power input module 40 at a first point A. Specifically, the first switch unit 11 is used to turn on when the voltage divider voltage is greater than a preset voltage and to turn off upon receiving a power-down control signal. The second switch unit 12 is used to turn on when the first switch unit 11 is on, to connect the path from the first point A to the first power source; and to turn off when the first switch unit 11 is off, to disconnect the path from the first point A to the first power source.

[0057] In this embodiment, as Figure 3 As shown, the preset voltage is the turn-on voltage of the first switching unit 11.

[0058] In some embodiments, the first switching unit 11 includes a switching transistor PQ2 and a resistor PR4. The control terminal of the switching transistor PQ2 is connected to the voltage divider module 20 and the switch control module 30, respectively. The first terminal of the switching transistor PQ2 is connected to the first terminal of the resistor PR4, the second terminal of the switching transistor PQ2 is grounded, and the second terminal of the resistor PR4 is connected to the power switch module 10.

[0059] In this embodiment, as Figure 3 As shown, the preset voltage is the turn-on voltage of the switching transistor PQ2. For example, the preset voltage can be 0.7V.

[0060] In this context, switch PQ2 can be an NMOS transistor or any other suitable switch. For example, when switch PQ2 is an NMOS transistor, the control terminal of switch PQ2 is the gate of the NMOS transistor, the first terminal of switch PQ2 is the drain of the NMOS transistor, and the second terminal of switch PQ2 is the source of the NMOS transistor.

[0061] In some embodiments, the second switching unit 12 includes a switching transistor PQ1, a resistor PR3, and a capacitor PC1. The first terminal of the switching transistor PQ1 is connected to the voltage divider module 20 and is also connected to the first power supply. The second terminal of the switching transistor PQ1 is connected to the first terminal of the resistor PR3, the first terminal of the capacitor PC1, and the power input module 40, respectively. The second terminal of the switching transistor PQ1 is also connected to the load. The control terminal of the switching transistor PQ1 is connected to the second terminal of the resistor PR3, the second terminal of the capacitor PC1, and the first switching unit 11. The second terminal of the switching transistor PQ1 is a first point A.

[0062] In this context, the switching transistor PQ1 can be a PMOS transistor or any other suitable switching transistor. For example, when the switching transistor PQ1 is a PMOS transistor, the control terminal of the switching transistor PQ1 is the gate of the PMOS transistor, the first terminal of the switching transistor PQ1 is the drain of the PMOS transistor, and the second terminal of the switching transistor PQ1 is the source of the PMOS transistor.

[0063] In some embodiments, the voltage divider module 20 includes resistors PR1 and PR2. A first terminal of resistor PR1 is connected to a first power supply, a second terminal of resistor PR1 is connected to the first terminal of resistor PR2 and the power switch module 10, and the second terminal of resistor PR2 is grounded.

[0064] Among them, such as Figure 3 As shown, the voltage divider is the voltage across resistor PR2. The voltage from the first power supply is divided by resistors PR1 and PR2 to obtain the voltage divider voltage. The value of the voltage divider voltage is related to the ratio of resistors PR1 to PR2. By adjusting the ratio of resistors PR1 to PR2, the magnitude of the voltage divider voltage can be adjusted.

[0065] In some embodiments, the power input module 40 includes a diode PD1, a capacitor PC2, and a capacitor PC3. The anode of diode PD1 is connected to the first terminals of both capacitor PC2 and PC3, and is also connected to a second power source. The cathode of diode PD1 is connected to the power switch module 10 and is also connected to the load. The second terminals of both capacitor PC2 and PC3 are grounded. The cathode of diode PD1 is at point A.

[0066] Among them, capacitors PC2 and PC3 are used for voltage stabilization, filtering, etc.

[0067] Please see Figure 4 , Figure 4 This is a schematic diagram of the circuit structure of the first interface 50 provided in an embodiment of this application.

[0068] In some embodiments, the first interface 50 includes a connector P1.

[0069] The connector P1 is used to connect to a power supply device (such as an ATX power supply) to receive the voltage of a first power supply, the voltage of a second power supply, and a power failure signal.

[0070] Specifically, pins 1, 2, and 3 of connector P1 are connected to... Figure 3 Resistor PR1 and switching transistor PQ1 are connected to transmit electrical energy from the first power supply. Pin 4 of connector P1 is connected to... Figure 3 The diode PD1 in the connector is connected to transmit power from the second power source. Pin 5 of connector P1 is connected to... Figure 3 The resistor PR5 in the circuit is connected to transmit the power-down signal.

[0071] The following is Figure 3 The working principle of the power switching circuit 100 will be illustrated with an example.

[0072] For example, such as Figure 3 As shown, assuming resistor PR1 has a resistance of 50KΩ, resistor PR2 has a resistance of 10KΩ, resistor PR3 has a resistance of 100KΩ, resistor PR4 has a resistance of 100KΩ, the first power supply is +12V, the second power supply is +5V, and the power-down signal is a high-level signal of 3.3V (when the voltage of +12V_SYS is less than 10.8V, the signal level at PSON# is 3.3V, i.e., the power-down signal; when the voltage of +12V_SYS is greater than or equal to 10.8V, the signal level at PSON# is 0V, i.e., the power-on signal). Then, in standby mode (standby mode includes sleep mode and power-off mode) and power-on mode, this power switching protection circuit 100... Figure 3 The voltages at each point (i.e., +12V_SYS, +5V_SB, PSON#, D, C, B, and A (also known as +12V_ALW_SYS), these seven points) are shown in Table 1 below:

[0073]

[0074] Table 1

[0075] Combination Figure 3 And as shown in Table 1, in practical applications:

[0076] When the DUT (test device) is in standby mode (either power-off or sleep mode), the second power supply ( Figure 3 The power supply connected at +5V_SB provides 5V DC power, while the first power supply ( Figure 3 The power supply connected at +12_SYS is not supplying power. At this time... Figure 1A power-down signal (3.3V) is input to the switch control module 30 at PSON#. Simultaneously, switch PQ3 is turned on, and point D is grounded, therefore the voltage level at point D is 0. Switch PQ2 is turned off, and point C is open-circuited. Switch PQ1 is also turned off, and the second power supply (+5V_SB point) supplies power to the load (point A) through diode PD1. At this time, the body diode of switch PQ1 prevents current from flowing back into +12V_SYS at point A.

[0077] When the DUT executes the first switching state, i.e., the switch from standby to power-on state, the second power supply continues to supply 5V DC, while the first power supply is powered up to supply 12V DC. The first power supply outputs 12V DC and supplies power to the load through the body diode of the switching transistor PQ1. At this time, when the voltage of the first power supply rises to 10.8V (10.8V is a preset threshold, which can be adjusted according to actual needs), the signal level at PSON# is 0, causing the switching transistor PQ3 to turn off. Simultaneously, after the voltage division by resistors PR1 / PR2, the level at point D is approximately 2V, and the switching transistor PQ2 turns on. This, in turn, causes the switching transistor PQ1 to turn on through the voltage division by resistors PR3 / PR4, and the first power supply supplies power to the load through the switching transistor PQ1. Diode PD1 in this circuit serves to prevent backflow from +12V_ALW_SYS to +5V_SB.

[0078] When the DUT is powered on, it is powered by both the first and second power supplies.

[0079] When the DUT executes the second switching state, i.e., the switch from power-on state to standby state, the second power supply continues to supply power, while the first power supply begins to power down. When the first power supply powers down, the level at +12V_SYS drops from 12V to below 10.8V, and the level of the signal at PSON# is set to 3.3V. Subsequently, switching transistor PQ3 turns on, and point D is grounded with a level of 0. Then, switching transistor PQ2 turns off, thereby turning off switching transistor PQ1. Due to the presence of the body diode of switching transistor PQ1, the second power supply, after passing through diode PD1, only supplies power to point A and does not flow back to +12V_SYS. This reduces the possibility of leakage and prevents damage to the load and the second power supply caused by abnormal conditions (such as reverse current, voltage fluctuations, etc.) resulting from the power failure of the first power supply, ensuring that the second power supply can continuously and stably supply power to the load and maintain the safe and stable operation of the entire circuit.

[0080] This application provides a power switching protection circuit 100, which can switch the path between the first power supply and the second power supply and the load by controlling the conduction and shutdown of the power switch module under different power supply states, ensuring that the load can be powered under different power supply states, thus improving the flexibility and reliability of power supply. When the first power supply is de-energized, the power switch module is turned off, which can effectively prevent the second power supply from supplying power in reverse through the path of the first power supply, avoiding possible current backflow problems and protecting other components in the circuit and the power supply itself.

[0081] This application provides a power switching protection device, which includes the power switching protection circuit 100 as described above.

[0082] The specific circuit structure and working principle of the power switching protection circuit 100 can be referred to the above embodiments, and will not be repeated here.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; under the concept of this utility model, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of this utility model as described above. For the sake of brevity, they are not provided in detail; although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A power supply switchover protection circuit, characterized by comprising: The power switching protection circuit comprises a power switch module, a voltage division module, a switch control module and a power input module; The power switch module is connected with the voltage division module, the switch control module and the power input module respectively, and the power switch module and the voltage division module are used for being connected with a first power supply, the power input module is used for being connected with a second power supply, and the power switch module and the power input module are used for being connected with a load at a first point; wherein a path from the first power supply to the first point through the power switch module is always on, and a path from the second power supply to the first point through the power input module is always on; When the first power supply is powered on, the voltage division module is used for dividing a first voltage of the first power supply to obtain a voltage division voltage, and the power switch module is used for being turned on when the voltage division voltage is greater than a preset voltage, so as to turn on the path from the first point to the first power supply; When the first power supply is powered off, the switch control module is used for outputting a power-off control signal based on a received power-off signal, and the power switch module is used for being turned off based on the power-off control signal, so as to disconnect the path from the first point to the first power supply.

2. The power supply switching protection circuit of claim 1, wherein, The power switch module is also used for being turned off when the voltage division voltage is less than or equal to the preset voltage, so as to disconnect the path from the first point to the first power supply.

3. The power switching protection circuit of claim 1, wherein, The switch control module comprises a switch tube PQ3 and a resistor PR5; A first end of the resistor PR5 is used for receiving the power-off signal, a second end of the resistor PR5 is connected with a control of the switch tube PQ3, a first end of the switch tube PQ3 is connected with the power switch module, and a second end of the switch tube PQ3 is grounded.

4. The power switching protection circuit of claim 1, wherein, The power switch module comprises a first switch unit and a second switch unit; The first switch unit is connected with the second switch unit, the voltage division module and the switch control module respectively, the second switch unit is also connected with the voltage division module, the second switch unit is used for being connected with the first power supply, and the second switch unit is also used for being connected with the load and the power input module at the first point; The first switch unit is used for being turned on when the voltage division voltage is greater than a preset voltage, and being turned off when the power-off control signal is received; The second switch unit is used for being turned on when the first switch unit is turned on, so as to turn on the path from the first point to the first power supply; The second switch unit is also used for being turned off when the first switch unit is turned off, so as to disconnect the path from the first point to the first power supply.

5. The power switching protection circuit of claim 4, wherein, The first switch unit comprises a switch tube PQ2 and a resistor PR4; A control end of the switch tube PQ2 is connected with the voltage division module and the switch control module respectively, a first end of the switch tube PQ2 is connected with a first end of the resistor PR4, a second end of the switch tube PQ2 is grounded, and a second end of the resistor PR4 is connected with the power switch module.

6. The power switching protection circuit of claim 4, wherein, The second switch unit comprises a switch tube PQ1, a resistor PR3 and a capacitor PC1; A first end of the switch tube PQ1 is connected with the voltage division module, the first end of the switch tube PQ1 is used for being connected with the first power supply, a second end of the switch tube PQ1 is respectively connected with a first end of the resistor PR3, a first end of the capacitor PC1 and the power input module, the second end of the switch tube PQ1 is used for being connected with the load, a control end of the switch tube PQ1 is connected with a second end of the resistor PR3, a second end of the capacitor PC1 and the first switch unit; wherein the second end of the switch tube PQ1 is the first point.

7. The power switching protection circuit of claim 1, wherein, The voltage division module comprises a resistor PR1 and a resistor PR2; A first end of the resistor PR1 is used for being connected with the first power supply, a second end of the resistor PR1 is connected with a first end of the resistor PR2 and the power switch module, a second end of the resistor PR2 is grounded.

8. The power switching protection circuit of claim 1, wherein, The power input module comprises a diode PD1, a capacitor PC2 and a capacitor PC3; A positive electrode of the diode PD1 is respectively connected with a first end of the capacitor PC2 and a first end of the capacitor PC3, the positive electrode of the diode PD1 is also used for being connected with the second power supply, a negative electrode of the diode PD1 is connected with the power switch module, the negative electrode of the diode PD1 is used for being connected with the load, a second end of the capacitor PC2 and a second end of the capacitor PC3 are both grounded; wherein the negative electrode of the diode PD1 is the first point.

9. The power switching protection circuit according to any one of claims 1 to 8, characterized in that, The power switch protection circuit further comprises a first interface; The first interface is respectively connected with the power switch module, the voltage division module, the switch control module and the power input module; The first interface is used for being connected with the first power supply, is also used for being connected with the second power supply, and is also used for receiving the power-off control signal.

10. A power switching protection device, characterized by, The power switch protection device comprises the power switch protection circuit according to any one of claims 1 to 9.

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