Circuit for solving switching power failure of power supply multiplexer

Abstract

The utility model provides a circuit for solving switching power failure of a power supply multiplexer. The circuit comprises a first voltage dividing member, a second voltage dividing member, a third voltage dividing member, a fourth voltage dividing member, a fifth voltage dividing member and the power supply multiplexer U12. VIN1-VIN2 is larger than or equal to the voltage drop of the first voltage dividing part by adjusting the resistance of the second voltage dividing part, the resistance of the third voltage dividing part, the resistance of the fourth voltage dividing part and the resistance of the fifth voltage dividing part, and therefore the system is not powered down. Complex power supply switching logic can be realized only by a small number of divider resistors and diodes, no extra control chip or software intervention is needed, BOM cost and PCB area are significantly reduced, and the circuit is suitable for a low-cost embedded system.

Description

Technical Field

[0001] This utility model relates to the field of power multiplexer switching technology, and in particular to a circuit for solving power failure during power multiplexer switching. Background Technology

[0002] Power multiplexers play an important role in industrial control systems. Their main function is to select and switch between multiple power inputs to ensure stable operation of the system under different power conditions.

[0003] Power outages may occur when using multiplexers for power switching. For example, when using dual power supply switching, the back-end circuitry may be damaged. This is usually because the voltage spikes generated during the switching process exceed the capacity of the back-end circuitry. Utility Model Content

[0004] In view of this, the purpose of this utility model is to propose a circuit for solving the problem of power failure when switching a power multiplexer, so as to solve the problem mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides a circuit for resolving power loss during switching of a power multiplexer, comprising: a first voltage divider, a second voltage divider, a third voltage divider, a fourth voltage divider, a fifth voltage divider, and a power multiplexer U12.

[0006] Pin 1 and pin 8 of the power multiplexer U12 are connected to the negative terminal of the first voltage divider; pin 7 of the power multiplexer U12 is also connected to the negative terminal of the first voltage divider; pin 1 of the power multiplexer U12 is also connected to a 7V input voltage; pin 1 of the power multiplexer U12 is also connected to capacitor C32 and then grounded; pin 7 of the power multiplexer U12 is also connected to the positive terminal of the main battery; pin 6 of the power multiplexer U12 is connected to the fourth voltage divider and then to the positive terminal of the main battery; pin 6 of the power multiplexer U12 is also connected to the fifth voltage divider and then grounded; pin 5 of the power multiplexer U12 is connected to resistor R35 and then grounded; pin 5 of the power multiplexer U12 is also connected to... After being connected to resistor R64, the power multiplexer U12 is connected to the positive terminal of the main battery; pin 2 of the power multiplexer U12 is connected to the positive terminal of the auxiliary battery and then to capacitor C51; pin 4 of the power multiplexer U12 is connected to resistor R69 and then to capacitor C51; capacitor C51 is grounded; pin 4 of the power multiplexer U12 is also connected to resistor R70 and then grounded; pin 3 of the power multiplexer U12 is connected to the second voltage divider and then to the positive terminal of the auxiliary battery; pin 3 of the power multiplexer U12 is also connected to the third voltage divider and then grounded; pin 9 of the power multiplexer U12 is grounded; pin 11 of the power multiplexer U12 is connected to capacitor C59 and then grounded; pin 10 of the power multiplexer U12 is connected to resistor R71 and then grounded.

[0007] In one embodiment, the first voltage divider is a diode SD15, the second voltage divider is a resistor R36, the third voltage divider is a resistor R68, the fourth voltage divider is a resistor R33, and the fifth voltage divider is a resistor R34.

[0008] In one embodiment, it further includes: a control power supply WF1;

[0009] The first interface of the control power supply WF1 is connected to the positive terminal of the main battery; the second interface of the control power supply WF1 is grounded.

[0010] As can be seen from the above, this utility model provides a circuit for solving the power failure problem when switching a power multiplexer. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the working circuit of this utility model under power failure conditions in an embodiment of the present invention;

[0013] Figure 2 A schematic diagram showing the power loss situation in the working circuit after introducing a 100K resistor in this embodiment of the utility model;

[0014] Figure 3 This is a schematic diagram of a circuit for solving the power failure switching of a power multiplexer according to an embodiment of the present invention. Detailed Implementation

[0015] Before describing the specific embodiments of this utility model, the overall concept of this utility model is explained as follows:

[0016] This utility model is mainly developed for the use of a power multiplexer. When the circuit is running, the voltages of PR1 and CP2 are compared. When the voltage at point PR1 is greater than or equal to the voltage at point CP2, the circuit is powered by IN1. When the voltage at point PR1 is less than the voltage at point CP2, the circuit is powered by IN2.

[0017] In actual testing, during the switching process, when the voltage at PR1 is lower than the voltage at CP2, the chip switches to IN2 output. Due to the load, IN1 rises slightly, and IN2 is pulled down. At this time, the voltage at CP2 will fall below the voltage at PR1 again, and the chip will switch to IN1 output again. However, due to the load, the chip will switch back to CP2 power supply. This back-and-forth switching causes the device to lose power.

[0018] like Figure 1 As shown, another scenario is caused by switching delay, where the output is pulled low for a period of about 200ms, resulting in a power outage of the entire circuit.

[0019] A 100K resistor was added between the ST and PR1 pins to introduce hysteresis, which addresses power-down issues in low-power scenarios. However, if... Figure 2 As mentioned above, the actual test waveform also showed that the output power was lost, but the voltage did not drop to 0V.

[0020] Therefore, this utility model proposes a circuit to solve the problem of power loss during switching of a power multiplexer. By adjusting the voltage dividing resistors through the first voltage divider, the second voltage divider, the third voltage divider, the fourth voltage divider, and the fifth voltage divider, the power multiplexer can be kept from losing power.

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

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] like Figure 3 As shown, this utility model provides a circuit for resolving power loss during switching of a power multiplexer, comprising: a first voltage divider, a second voltage divider, a third voltage divider, a fourth voltage divider, a fifth voltage divider, and a power multiplexer U12. The first voltage divider uses a diode SD15, the second voltage divider uses a resistor R36, the third voltage divider uses a resistor R68, the fourth voltage divider uses a resistor R33, and the fifth voltage divider uses a resistor R34.

[0024] Specifically, the first voltage divider can be a Schottky diode. Schottky diodes have ultra-fast recovery times (nanosecond level), enabling instantaneous response to switching actions and establishing temporary paths within μs time, adapting to high-frequency switching scenarios (such as battery / adapter hot-swapping) and reducing voltage fluctuation windows.

[0025] Pins 1 and 8 of power multiplexer U12 are connected to the negative terminal of the first voltage divider, and pin 7 of power multiplexer U12 is connected to the positive terminal of the first voltage divider. Pin 1 of power multiplexer U12 is also connected to the 7V input voltage. Pin 1 of power multiplexer U12 is also connected to capacitor C32 and then grounded. Pin 7 of power multiplexer U12 is also connected to the positive terminal of the main battery. Pin 6 of power multiplexer U12 is connected to the fourth voltage divider and then to the positive terminal of the main battery. Pin 6 of power multiplexer U12 is also connected to the fifth voltage divider and then grounded. Pin 5 of power multiplexer U12 is connected to resistor R35 and then grounded. Pin 5 of power multiplexer U12 is also connected to resistor R64 and then to the main battery. The battery positive terminal is connected; pin 2 of power multiplexer U12 is connected to the positive terminal of the auxiliary battery and then to capacitor C51; pin 4 of power multiplexer U12 is connected to resistor R69 and then to capacitor C51; capacitor C51 is grounded; pin 4 of power multiplexer U12 is also connected to resistor R70 and then to grounded; pin 12 of power multiplexer U12 is grounded; pin 3 of power multiplexer U12 is connected to the second voltage divider and then to the positive terminal of the auxiliary battery; pin 3 of power multiplexer U12 is also connected to the third voltage divider and then to grounded; pin 9 of power multiplexer U12 is grounded; pin 11 of power multiplexer U12 is connected to capacitor C59 and then to grounded; pin 10 of power multiplexer U12 is connected to resistor R71 and then to grounded.

[0026] Also includes: Control power supply WF1;

[0027] Interface 1 of the control power supply WF1 is connected to the positive terminal of the main battery; interface 2 of the control power supply WF1 is grounded.

[0028] By adjusting the resistors of the second, third, fourth, and fifth voltage dividers, the voltage at pins 6 and 3 of the power multiplexer U12 is adjusted to make V... IN1 -V IN2 ≥ Pressure drop of the first pressure component.

[0029] Under normal operating conditions, the voltage drop of the first voltage divider will be higher than the voltage drop of the chip itself, so that current will not flow through the first voltage divider. When switching to IN2 output, the output voltage is higher than IN1, and no current will flow through the first voltage divider. During the switching process, whether it is back-and-forth switching or switching delay, current will be supplied to the main output, so that the system will not lose power.

[0030] This utility model provides a circuit for solving the power failure during power switching of a power multiplexer. By setting up a voltage divider, at the moment of power switching (such as IN1→IN2 or IN2→IN1), the first voltage divider provides a temporary current path to ensure that the voltage at the main output terminal does not drop, thus avoiding system restart or data loss due to transient power failure.

[0031] During normal operation, the internal voltage drop of the chip falls below the conduction threshold of the first voltage divider (e.g., 0.3V vs 0.5V). The first voltage divider is in a reverse-biased cutoff state, allowing current to flow entirely through the chip and preventing additional power consumption caused by leakage current from the first voltage divider. When switching to IN2 power supply, if the IN2 voltage is higher than IN1, the first voltage divider automatically cuts off due to reverse bias, preventing reverse current from flowing from IN2 to IN1; conversely, the reverse bias also prevents reverse current from flowing from IN2 to IN1. This feature protects the power module from reverse current surges, improving system reliability.

[0032] This invention requires only a small number of voltage divider resistors and diodes to implement complex power switching logic, eliminating the need for additional control chips or software intervention. This significantly reduces BOM costs and PCB area, making it suitable for low-cost embedded systems. By adjusting the ratio of the voltage divider resistors, it can accommodate different Schottky diode voltage drops (e.g., 0.3V-0.7V) and set differentiated switching threshold voltages, meeting the compatibility requirements of multi-voltage systems (e.g., 3.3V / 5V / 12V).

[0033] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; within the framework of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in the details for the sake of brevity.

[0034] The embodiments of this utility model are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A circuit for resolving power failure during switching in a power multiplexer, characterized in that, include: First pressure divider, second pressure divider, third pressure divider, fourth pressure divider, fifth pressure divider and power multiplexer U12; Pin 1 and pin 8 of the power multiplexer U12 are connected to the negative terminal of the first voltage divider; pin 7 of the power multiplexer U12 is connected to the positive terminal of the first voltage divider; pin 1 of the power multiplexer U12 is also connected to a 7V input voltage; pin 1 of the power multiplexer U12 is also connected to capacitor C32 and then grounded; pin 7 of the power multiplexer U12 is also connected to the positive terminal of the main battery; pin 6 of the power multiplexer U12 is connected to the fourth voltage divider and then to the positive terminal of the main battery; pin 6 of the power multiplexer U12 is also connected to the fifth voltage divider and then grounded; pin 5 of the power multiplexer U12 is connected to resistor R35 and then grounded; pin 5 of the power multiplexer U12 is also connected to resistor R64 and then to... The main battery is connected to the positive terminal; pin 2 of the power multiplexer U12 is connected to the positive terminal of the auxiliary battery and then to capacitor C51; pin 4 of the power multiplexer U12 is connected to resistor R69 and then to capacitor C51; capacitor C51 is grounded; pin 4 of the power multiplexer U12 is also connected to resistor R70 and then to grounded; pin 12 of the power multiplexer U12 is grounded; pin 3 of the power multiplexer U12 is connected to the second voltage divider and then to the positive terminal of the auxiliary battery; pin 3 of the power multiplexer U12 is also connected to the third voltage divider and then to grounded; pin 9 of the power multiplexer U12 is grounded; pin 11 of the power multiplexer U12 is connected to capacitor C59 and then to grounded; pin 10 of the power multiplexer U12 is connected to resistor R71 and then to grounded.

2. The circuit for resolving power failure during switching of a power multiplexer according to claim 1, characterized in that, The first voltage divider uses a diode SD15, the second voltage divider uses a resistor R36, the third voltage divider uses a resistor R68, the fourth voltage divider uses a resistor R33, and the fifth voltage divider uses a resistor R34.

3. The circuit for resolving power failure during switching of a power multiplexer according to claim 1, characterized in that, Also includes: Control power supply WF1; The control power supply WF1's interface 1 is connected to the positive terminal of the main battery; The control power supply WF1 has its interface 2 grounded.

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