An emergency power starting circuit

Abstract

The application provides an emergency power supply starting circuit, and belongs to the technical field of integrated circuits, and comprises a high-voltage input end for providing a high-voltage input; a voltage storage circuit comprising a first resistor R1 and a first capacitor C1, and an input end connected with the high-voltage input end; a comparator circuit comprising a comparator U1, a positive input end connected with an output end of the voltage storage circuit, a negative input end for providing a low-voltage input, and an output end connected with a control switch group; and the control switch group is connected with a control chip; the comparator U1 in the comparator circuit is reversed according to the voltage storage circuit and the low-voltage input, controls on-off of the control switch group, and supplies power to the control chip for starting, so that the problem that the existing emergency power supply starting circuit has high power consumption for high-voltage power taking and has high requirements on the control chip is solved.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit technology, and in particular to an emergency power supply start-up circuit. Background Technology

[0002] As people's living standards improve, the demand for cars is increasing. Due to the wide variety of cars on the market and the inconsistent quality of their parts, car electrical systems are prone to failure. When a car's electrical system fails or is out of power, an emergency power supply is usually activated.

[0003] Current emergency power supplies require high-voltage power for startup, typically achieved using resistors to convert high voltage to low voltage. However, if continuous high-voltage power is required for startup, a small resistor value leads to high power loss, while a large resistor value fails to meet startup power demands. To achieve low-power power extraction, the power supply chip must support higher voltage startup and lower voltage shutdown; however, most flyback control chips currently lack this capability. Summary of the Invention

[0004] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide an emergency power supply start-up circuit that solves the problems of high power consumption from high voltage power extraction and high requirements for control chips in existing emergency power supply start-up circuits.

[0005] This invention discloses an emergency power supply start-up circuit, comprising:

[0006] The high-voltage input terminal provides high-voltage input.

[0007] The voltage storage circuit includes a first resistor R1 and a first capacitor C1, and its input terminal is connected to the high voltage input terminal.

[0008] The comparator circuit includes comparator U1, with its positive input terminal connected to the output terminal of the voltage storage circuit, its negative input terminal providing a low voltage input, and its output terminal connected to a control switch group.

[0009] The output of the control switch group is connected to the control chip;

[0010] The comparator U1 in the comparator circuit controls the on / off state of the control switch group according to the voltage storage circuit and the low voltage input, thereby providing power to the control chip for startup.

[0011] Preferably, the control switch group includes a first control switch Q1 and a second control switch Q2;

[0012] The input terminal of the first control switch Q1 is connected to the output terminal of the comparator circuit, and the output terminal is connected to the second control switch Q2 to control the on / off state of the input terminal to the output terminal of the second control switch Q2;

[0013] The input terminal of the second control switch Q2 is connected to the output terminal of the voltage storage circuit, and the output terminal is used to connect to the control chip.

[0014] Preferably, the first control switch Q1 is an NMOS or NPN transistor, and the second control switch Q2 is a PMOS or PNP transistor.

[0015] Preferably, the second control switch Q2 is unidirectionally conductive from its input to its output.

[0016] Preferably, the comparator circuit further includes:

[0017] The second resistor R2 is connected at one end to the positive input terminal of the comparator U1 and at the other end to the output terminal of the voltage storage circuit.

[0018] Preferably, the comparator circuit further includes:

[0019] The third resistor R3 is connected at one end to the output terminal of the comparator U1 and at the other end to the output terminal of the second resistor R2.

[0020] Preferably, a voltage divider circuit is formed by connecting a low-voltage power supply to a voltage divider resistor or a REF chip, and then connected to the negative input terminal of the comparator U1 to provide a low-voltage input.

[0021] Preferably, when the voltage at the positive input terminal of comparator U1 in the comparator circuit is higher than that at the negative input terminal, the comparator outputs a high level, causing the first control switch Q1 to control the second control switch Q2 to be turned on, and the voltage storage circuit supplies power to the control chip through the second control switch Q2 to start it up.

[0022] When the power supply to the control chip fails to start, the voltage at the positive input terminal of comparator U1 in the comparator circuit drops below that at the negative input terminal. The comparator then flips, causing the first control switch Q1 to open and the second control switch Q2 to open, thus stopping the power supply to the control chip.

[0023] Preferably, after receiving the power supply feedback signal from the control chip, the second control switch Q2 is connected to the steady-state output of the control chip.

[0024] Compared with existing technologies, the above technical solution has the following advantages:

[0025] The emergency power supply startup circuit provided in this application sets up a voltage storage circuit formed by a capacitor, which is connected to a control chip through a control switch group. At the same time, the voltage storage circuit is connected to a comparator circuit. The switching of the control switch group is controlled by the flipping of the comparator U1, thereby realizing a high-voltage power-taking, low-power startup circuit. After the control chip is powered, it controls the emergency power supply to start safely. Through this comparator circuit, the high-voltage startup voltage and low-voltage startup voltage can be flexibly configured, solving the problem that the existing emergency power supply startup circuit has high power consumption due to high-voltage power taking and high requirements for the control chip. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the circuit structure of an emergency power supply start-up circuit according to the present invention;

[0027] Figure 2 This is a voltage change curve of the voltage storage circuit output and the second control switch Q2 output in the emergency power supply start-up circuit of the present invention. Detailed Implementation

[0028] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0030] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0032] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0034] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0035] Example: This example discloses an emergency power supply startup circuit. This circuit draws power from the high-voltage bus to supply power to the power control chip, enabling the emergency power supply to start safely. Specifically, it achieves low power consumption from high-voltage power supply and provides hysteresis power externally through a comparator circuit. It also allows for flexible configuration of high-voltage and low-voltage startup voltages, while avoiding potential damage to components caused by starting with a lower power supply at high voltage. See also... Figure 1 The circuit provided in this application includes:

[0036] The high-voltage input terminal provides high-voltage input, meaning it needs to draw power from high voltage.

[0037] The voltage storage circuit includes a first resistor R1 and a first capacitor C1, with its input terminal connected to the high-voltage input terminal. For illustration, the first capacitor C1 draws power from the high voltage and stores energy, ensuring that a voltage Vc can still be output to power the control chip even when high-voltage power is unavailable. Multiple first resistors R1 can be provided as supplementary high-voltage draw-out resistors with large resistance values, allowing the circuit to maintain a relatively safe steady-state output after the emergency power supply is activated. A Zener diode is also connected to ground after the high-voltage input terminal is connected to the first resistor R1 to ensure circuit safety. Multiple first capacitors C1 can also be provided to achieve better energy storage functionality.

[0038] The comparator circuit includes comparator U1, with its positive input terminal connected to the output terminal of the voltage storage circuit, its negative input terminal providing a low-voltage input, and its output terminal connected to a control switch group. The comparator is a circuit that compares an analog voltage signal with a reference voltage. In this embodiment, the analog voltage signal is the output of the voltage storage circuit, and the reference voltage is the low-voltage power supply provided to the comparator to enable its operation. That is, comparator U1 in the comparator circuit controls the on / off state of the control switch group based on the voltage storage circuit and the low-voltage input, thus providing startup power to the control chip.

[0039] Specifically, the control switch group includes a first control switch Q1 and a second control switch Q2. The input terminal of the first control switch Q1 is connected to the output terminal of the comparator circuit, and the output terminal is connected to the second control switch Q2 to control the switching between the input and output terminals of the second control switch Q2. The input terminal of the second control switch Q2 is connected to the output terminal of the voltage storage circuit, and the output terminal is used to connect to the control chip. Optionally, the first control switch Q1 is an NMOS or NPN transistor, and the second control switch Q2 is a PMOS or PNP transistor. The first control switch Q1 acts as a conducting element, and the above control can be achieved by other existing low-impedance conducting elements, which can also replace the first control switch Q1 in this application.

[0040] Specifically, the comparator circuit includes:

[0041] A low-voltage power supply is provided, which is connected to a voltage divider resistor or a REF chip to form a voltage divider circuit. This voltage divider circuit is then connected to the negative input terminal of the comparator U1 to provide a low-voltage input. This low-voltage power supply is used to start the comparator circuit. The low-voltage power supply is at 5V. In the startup circuit provided in this embodiment, the comparator circuit needs to be started before the comparator U1 can control the on / off switching of the power supply output to the control chip based on the output comparison and flipping control of the voltage storage circuit. Alternatively, a low-voltage power supply can be obtained directly from the high-voltage input terminal, but the mutual interference between circuits needs to be considered according to the specific implementation scenario.

[0042] Comparator U1 has its positive input terminal connected to the output terminal of the voltage storage circuit, its negative input terminal connected to the low-voltage input, and its output terminal connected to the first control switch Q1. It flips the voltage storage circuit output by comparing it with the low-voltage input, thereby controlling the on / off state of the first control switch Q1 connected to the output terminal.

[0043] As explained, the negative input terminal of comparator U1 is preset to have a low voltage input Vref. When the voltage at the positive input terminal of comparator U1 in the comparator circuit is higher than that at the negative input terminal, the comparator outputs a high level, causing the first control switch Q1 to control the second control switch Q2 to conduct. The voltage storage circuit then supplies power to the control chip through the second control switch Q2. If the power supply to the control chip fails to start, the voltage at the positive input terminal of comparator U1 in the comparator circuit drops to the negative input terminal, causing the comparator to flip, thus opening the first control switch Q1 and the second control switch Q2, stopping the power supply to the control chip.

[0044] In this embodiment, power is drawn from the high-voltage input terminal and enters the voltage storage circuit. The first capacitor C1 is charged and discharged. Comparator U1 is pre-started via a low-voltage power supply. The output of the first capacitor C1 and the low-voltage input provided by the voltage divider circuit formed by the low-voltage power supply serve as the input to comparator U1. When the voltage at the positive input terminal of comparator U1 is higher than that at the negative input terminal, the comparator outputs a high level. At this time, the first control switch Q1 is turned on, and then the second control switch Q2 is turned on. The current output to the control chip increases until the output of the first capacitor C1 can supply power to the control chip through the second control switch Q2 to start it up. If the previous... If the operation fails to start, the current output from the second control switch Q2 to the control chip will decrease because the control chip fails to start the emergency power supply. The voltage at the positive input terminal of comparator U1 in the comparator circuit will gradually decrease to below the negative input terminal, and comparator U1 will flip again. The first control switch Q1 will open, and the second control switch Q2 will open, returning to the initial state. The aforementioned start-up process will be executed again until the control chip starts the emergency power supply. After success, after receiving the power supply feedback signal from the control chip, the second control switch Q2 will connect to the steady-state output of the control chip, that is, the control chip starts the emergency power supply. This circuit will have a high voltage input, which will be maintained at a small steady-state input through the first resistor R1.

[0045] In the above embodiment, the comparator circuit further includes: a second resistor R2, one end of which is connected to the positive input terminal of the comparator U1, and the other end of which is connected to the output terminal of the voltage storage circuit, providing certain protection for the circuit. Further, it also includes a third resistor R3, one end of which is connected to the output terminal of the comparator U1, and the other end of which is connected to the output terminal of the second resistor R2. This ensures that if the comparator U1 flips for the first time, providing startup power to the control chip, but the control chip fails to start and needs to be restarted, the voltage at the positive input terminal of the comparator U1 gradually decreases to below the negative input terminal. R2 and R3 then create a hysteresis loop, allowing the positive input terminal to quickly reach a voltage exceeding that of the negative input terminal again, thus resuming power supply to the control chip. This allows for rapid, multiple-cycle startups until the control chip successfully starts the emergency power supply.

[0046] Specifically, the low-voltage power supply for the comparator U1 is provided by a voltage divider circuit formed by the low-voltage power supply. This voltage divider circuit can optionally include multiple voltage divider resistors or REF chips (such as TLV431). The series / parallel connection of each voltage divider resistor and their respective resistance values ​​can control the reference voltage of comparator U1 (i.e., Vref used for comparison), thereby controlling the threshold voltage at which the comparator flips. Capacitors or other components can also be connected to further assist in controlling the output of the voltage divider circuit.

[0047] In this embodiment, specifically, to achieve the control of the voltage storage circuit and the first control switch Q1 through the conduction of the first control switch Q1, so as to control the output of the control chip, taking the first control switch Q1 as a MOSFET Q1 and the second control switch Q2 as a transistor as an example, its gate is connected to the output terminal of the comparator circuit, its source is grounded, and its drain is connected to the base of the first control switch Q2. After the comparator circuit turns on the first control switch Q1 through the gate of the first control switch Q1, the first control switch Q1 turns on its base, so that the voltage output by the voltage storage circuit is provided to the control chip.

[0048] In this embodiment, as a supplement, the startup circuit of this application is used to control the startup circuit of the emergency power supply of the control chip. As described above, the output of the second control switch Q2 is connected to the control chip. When the first control switch Q1 is turned on, the voltage storage circuit output causes the control chip to start the emergency power supply. Then the control chip is powered by the emergency power supply. The specific control chip, i.e. the emergency power supply circuit, is the same as the existing circuit and will not be shown or described in detail here.

[0049] Further, the input terminal to the output terminal of the second control switch Q2 conducts unidirectionally to avoid current backflow after the control chip is started. When the startup circuit provided in this application receives the power supply feedback signal from the control chip, the second control switch Q2 is connected to the steady-state output of the control chip. When the control chip starts the emergency power supply, due to the relatively large first resistor R1, the power supply of the control chip is stable. Therefore, this startup circuit only needs to maintain a relatively small steady-state power supply output.

[0050] Based on the above, the emergency power supply startup circuit provided in this application sets up a voltage storage circuit formed by a capacitor (i.e., the first capacitor C1), which is connected to the control chip through the second control switch Q2. At the same time, the voltage storage circuit is connected to the comparator circuit, and the first control switch Q1 is connected to the second control switch Q2 to control the on / off of the second control switch Q2 according to the comparison between the voltage storage circuit and the low-voltage input of the comparator U1. Thus, a startup circuit with high-voltage power extraction and low power consumption is realized, enabling the control chip to safely start the emergency power supply after being powered. Based on this circuit, the high-voltage startup voltage and the low-voltage startup voltage can be flexibly configured, and there is no need for the control chip to have functions such as starting with a higher voltage and turning off with a lower voltage.

[0051] Further, the startup circuit provided in this application can also achieve multiple cycle startups. As described above, the output terminal of the comparator U1 is connected to the positive input terminal through the third resistor R3, and R2 and R3 form a hysteresis, so that part of the electrical energy output by the comparator U1 can flow back to the input terminal. When the first startup signal is applied and Vref < Vc*(R2 + R3) / R3, the comparator outputs a high level Vdd, Q2 conducts, and the voltage storage circuit and the control chip are started through the first control switch Q1 and the second control switch Q2. If the startup fails, the voltage at the positive input terminal of the comparator U1 drops. Since part of the electrical energy at the output terminal is added to the input terminal, when Vref > (Vc*R3 / (R2 + R3) + Vdd*R2 / (R2 + R3)), the comparator outputs a low level, and the first control switch Q1 and the second control switch Q2 are turned off. Then, the voltage at the positive input terminal of the comparator U1 quickly reaches the invertible threshold again, and the voltage storage circuit and the control chip are re-conducted, as Figure 2 shown. Figure 2The upper diagram shows the voltage change of the voltage storage circuit output, and the lower diagram shows the voltage change of the transistor output. When the circuit starts to be used, the voltage output of the voltage storage circuit gradually increases. At this time, Vout = 0 until the upper limit threshold is reached. The flipper flips, and the second control switch Q2 can output Vout to power the control chip. If the control chip fails to start the emergency power supply, the voltage output of the voltage storage circuit gradually decreases. When Vref > (Vc*R3 / (R2+R3)+Vdd*R2 / (R2+R3)), the comparator flips, the second control switch Q2 is opened, and Vout outputs 0 again. The above start-up process is repeated to realize multiple cyclic start-ups, low power consumption, flexible configuration and good versatility.

[0052] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An emergency power supply start-up circuit, characterized in that, include: The high-voltage input terminal provides high-voltage input. The voltage storage circuit includes a first resistor R1 and a first capacitor C1, and its input terminal is connected to the high voltage input terminal. The comparator circuit includes comparator U1, with its positive input terminal connected to the output terminal of the voltage storage circuit, its negative input terminal providing a low voltage input, and its output terminal connected to a control switch group. The output of the control switch group is connected to the control chip; Comparator U1 in the comparator circuit flips with the low-voltage input according to the voltage storage circuit, controls the on / off state of the control switch group, and provides startup power to the control chip; The control switch group includes a first control switch Q1 and a second control switch Q2; The input terminal of the first control switch Q1 is connected to the output terminal of the comparator circuit, and the output terminal is connected to the second control switch Q2 to control the on / off state of the input terminal to the output terminal of the second control switch Q2; The input terminal of the second control switch Q2 is connected to the output terminal of the voltage storage circuit, and the output terminal is used to connect to the control chip; The comparator circuit further includes: The second resistor R2 is connected at one end to the positive input terminal of the comparator U1 and at the other end to the output terminal of the voltage storage circuit. The comparator circuit further includes: The third resistor R3 is connected at one end to the output terminal of the comparator U1 and at the other end to the output terminal of the second resistor R2; When the voltage at the positive input terminal of comparator U1 in the comparator circuit is higher than that at the negative input terminal, the comparator outputs a high level, causing the first control switch Q1 to control the second control switch Q2 to be turned on, and the voltage storage circuit supplies power to the control chip through the second control switch Q2 to start it up. When the power supply to the control chip fails to start, the voltage at the positive input terminal of comparator U1 in the comparator circuit drops below that at the negative input terminal. The comparator then flips, causing the first control switch Q1 to open and the second control switch Q2 to open, thus stopping the power supply to the control chip.

2. The emergency power supply start-up circuit according to claim 1, characterized in that: The first control switch Q1 is an NMOS or NPN transistor, and the second control switch Q2 is a PMOS or PNP transistor.

3. The emergency power supply start-up circuit according to claim 1, characterized in that: The second control switch Q2 is unidirectionally connected from its input to its output.

4. The emergency power supply start-up circuit according to claim 1, characterized in that: A voltage divider circuit is formed by connecting a low-voltage power supply to a voltage divider resistor or a REF chip, and then connected to the negative input terminal of the comparator U1 to provide a low-voltage input.

5. The emergency power supply start-up circuit according to claim 1, characterized in that: After receiving the power supply feedback signal from the control chip, the second control switch Q2 is connected to the steady-state output of the control chip.

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