Power supply device with hold-up time extension function

Abstract

A power supply device having a hold-up time extension function is disclosed. The power supply device having a hold-up time extension function according to the present invention includes: a power supply unit comprising a main power supply and a sub-power supply that supply power to a load; a comparator unit that outputs a fault voltage arrival signal when the voltage of the main power supply reaches a preset fault voltage lower than the normal voltage of the main power supply as the power supplied to the main power supply is cut off and the voltage of the main power supply drops; a hold-up time extension circuit connected in parallel to the sub-power supply; and a control unit that drives the hold-up time extension circuit when the time from the point of power supply to the main power supply being cut off to the point of the fault voltage arrival is shorter than a preset time. The present invention can provide a power supply device having a hold-up time extension function that can extend the hold-up time while maintaining the capacitance of the sub-capacitor.

Description

Technology Field

[0001] The present invention relates to a power supply device having a hold-up time extension function, and more specifically, to a power supply device having a hold-up time extension function that allows the time required for a load to back up data, i.e., the hold-up time, to be extended when the power supplied to the main power supply is cut off. Background Technology

[0003] FIG. 1 is a circuit diagram showing an equivalent circuit of a power supply device according to the prior art, FIG. 2 is a diagram showing the change in voltage of the main power supply and sub power supply over time when the power supplied to the power supply unit of the power supply device shown in FIG. 1 is cut off, and FIG. 3 is a photograph showing the circuit layout design of the PCB of the power supply device according to the prior art.

[0004] Referring to FIG. 1, an equivalent circuit (100) of a power supply device according to the prior art includes a power supply unit (10), a comparator (20), and a load. When the power supply unit (10) is driven, the input power (Vs), which is a DC power source, supplies power to the main power (Cm) and the sub power (Cs), and the power charged in the main power (Cm) and the sub power (Cs) is supplied to the load. In this example, the main power (Cm) is the main capacitor, and the sub power (Cs) is the sub capacitor. If a problem occurs in the input power (Vs) or the power supply system connected prior to the input power (Vs), and the power supplied to the main power (Cm) and the sub power (Cs) is cut off (or interrupted), the voltage level of the main power (Cm) gradually drops. At this time, the power supply unit (10) must ensure a minimum time for the load to back up data or record information required for the MCU (Micro Control Unit), and this minimum time is referred to as the hold-up time in the industry.

[0005] Referring to FIG. 2, the hold-up time of the equivalent circuit (100) of a power supply device according to the prior art will be described. The upper graph (40) of FIG. 2 shows the change in voltage of the main power supply (Cm) when power is cut off, and the lower graph (45) shows the change in voltage of the sub power supply (Cs). Here, the normal voltage of the main power supply (Cm) is 13V in this example as a DC voltage. Also, the normal voltage of the sub power supply (Cs) is 3.3V in this example as a DC voltage. When the power supplied to the main power supply (Cm) is cut off (Power loss), the voltage level of the main power supply (Cm) gradually decreases. The point of power loss is the point of T1. As the voltage level of the main power supply (Cm) gradually decreases, a preset fault voltage (V) lower than the normal voltage is reached. PF When the Voltage Power fail (e.g., 10V) is reached, the comparator (20) outputs a fault voltage arrival signal. Here, the fault voltage (V PF The point of arrival becomes the end point of T1 and the start point of T2. Even if the power is cut off, the normal voltage of the sub-power (Cs) (e.g., 3.3V) is maintained for a while because the main power (Cm) supplies power to the sub-power (Cs). However, as the voltage level of the main power (Cm) drops further, the loss voltage (V REG , 3.3V Regulator input Power Loss (4.8V in this example) is reached when power supply from the main power (Cm) to the sub power (Cs) is interrupted. Here, the voltage loss (V REGThe point at which ) is reached becomes the end point of T2 and the start point of T3. When the power supply from the main power source (Cm) to the sub-power source (Cs) is interrupted, the voltage level of the sub-power source (Cs), which had been maintaining a normal voltage (3.3V in this example), gradually drops. The point at which the voltage level of the sub-power source (Cs) gradually drops and reaches a preset minimum voltage (e.g., 1.7V), which is lower than the normal voltage, becomes the end point of T3. At this time, the hold-up time (T Hold-UP ) is defined as T1+T2+T3.

[0006] Generally, a hold-up time of at least a preset time (e.g., 50ms) must be secured. Under normal circumstances, a hold-up time of 50ms or more can be secured; however, in special situations (e.g., when the load is heavier than expected and T1+T2 becomes smaller than usual), the hold-up time may drop below 50ms. Additionally, in some cases, it may be necessary to secure a hold-up time longer than usual. The simplest method to extend or expand the hold-up time is to consider increasing the capacity of the sub-capacitor (Cs), i.e., the sub-capacitor (Cs). However, increasing the capacity of the sub-capacitor (Cs) entails increasing its size, and as illustrated in Fig. 3, there are cases where it is impossible to increase the size of the sub-capacitor (Cs) on a PCB that is already designed compactly. In this case, there is a problem in that the entire circuit layout design of the PCB must be redone to secure space for the increased-size sub-capacitor. Prior art literature

[0008] KR 10-0985566KR 10-2467961KR 10-1739552US 11953971 The problem to be solved

[0009] Accordingly, the present invention is devised to solve the aforementioned problems and aims to provide a power supply device having a hold-up time extension function that can extend the hold-up time while maintaining the capacitance of the sub-capacitor.

[0010] In addition, the present invention provides a power supply device having a hold-up time extension function that can adjust the length of the hold-up time as needed.

[0011] Other objects of the present invention will become more apparent through the preferred embodiments described below. means of solving the problem

[0013] According to one aspect of the present invention, a power supply device having a hold-up time extension function comprises: a power supply unit including a main power supply and a sub-power supply that supply power to a load; a comparator unit that outputs a fault voltage arrival signal when the voltage of the main power supply reaches a preset fault voltage lower than the normal voltage of the main power supply as the power supplied to the main power supply is cut off and the voltage of the main power supply drops; a hold-up time extension circuit connected in parallel to the sub-power supply; and a control unit that drives the hold-up time extension circuit when the time from the time of power supply to the main power supply being cut off to the time of the fault voltage arrival is shorter than a preset time.

[0014] Here, the hold-up time extension circuit comprises a first switch connected to the output terminal of the sub-power supply;

[0015] It may include a second switch connected to the first switch; and an expansion capacitor connected between the point where the first switch and the second switch are connected and the output terminal of the sub-power supply.

[0016] Here, the control unit can charge the expansion capacitor by switching on the first switch during the initial operation of the power supply unit.

[0017] Here, if the time from the point of interruption of power supplied to the main power source to the point of reaching the fault voltage is shorter than a preset time, the control unit can switch on the second switch to output the power charged in the expansion capacitor.

[0018] Here, when the voltage of the main power supply reaches a preset loss voltage that is lower than the fault voltage and higher than the normal voltage of the sub power supply, the control unit can switch on the second switch.

[0019] Here, the main power source may be a main capacitor that receives power from an input power source, charges it, and then supplies power to a load.

[0020] Here, the sub-power supply may be a sub-capacitor that is charged by receiving power from an input power supply.

[0021] Here, when the voltage of the main power supply reaches a preset loss voltage that is lower than the fault voltage and higher than the normal voltage of the sub power supply, the power supply from the main power supply to the sub power supply may be interrupted. Effects of the invention

[0023] Accordingly, the present invention can provide a power supply device having a hold-up time extension function that can extend the hold-up time while maintaining the capacitance of the sub-capacitor.

[0024] In addition, the present invention can provide a power supply device having a hold-up time extension function that can adjust the length of the hold-up time as needed. Brief explanation of the drawing

[0026] FIG. 1 is a circuit diagram showing an equivalent circuit of a power supply device according to the prior art. FIG. 2 is a diagram showing the change in voltage of the main power and sub power over time when the power supplied to the power supply unit in the power supply unit shown in FIG. 1 is cut off. Figure 3 is a photograph showing the circuit layout design of a PCB of a power supply device according to the prior art. FIG. 4 is a circuit diagram showing an equivalent circuit of a power supply device having a hold-up time extension function according to one embodiment of the present invention. FIG. 5 is a diagram showing the change in voltage of the main power and sub power over time when the power supplied to the power supply unit is cut off in a power supply having a hold-up time extension function shown in FIG. 4. Specific details for implementing the invention

[0027] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention.

[0028] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0029] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0031] FIG. 4 is a circuit diagram showing an equivalent circuit of a power supply device having a hold-up time extension function according to one embodiment of the present invention, and FIG. 5 is a diagram showing the change in voltage of the main power supply and the sub power supply over time when the power supplied to the power supply unit in the power supply device having a hold-up time extension function shown in FIG. 4 is cut off.

[0032] As illustrated in FIG. 4, an equivalent circuit (200) of a power supply device having a hold-up time extension function according to one embodiment of the present invention includes a power supply unit (10) comprising a main power supply (Cm) and a sub power supply (Cs) that supply power to a load; a comparator (20) that outputs a fault voltage arrival signal when the voltage of the main power supply (Cm) reaches a preset fault voltage lower than the normal voltage of the main power supply (Cm) as the power supplied to the main power supply (Cm) is cut off and the voltage of the main power supply (Cm) drops; a hold-up time extension circuit (30) connected in parallel to the sub power supply (Cs); and a control unit (not shown) that drives the hold-up time extension circuit (30) when the time from the time of cutting off the power supplied to the main power supply (Cm) to the time of reaching the fault voltage is shorter than a preset time.

[0033] When the power supply unit (10) is operated, the input power (Vs), which is a DC power, supplies power to the main power (Cm) and the sub power (Cs), and the power charged in the main power (Cm) and the sub power (Cs) can be supplied to the load. The main power (Cm) may be the main capacitor (Cm), and the sub power (Cs) may be the sub capacitor (Cs). In the example shown in FIG. 4, the input power (Vs) may be DC 13V, the main capacitor (Cm) may be a 2.2mF capacitor, and the sub capacitor (Cs) may be a 100uF capacitor. The main capacitor (Cm) can perform the function of receiving power from the input power (Vs), charging it, and then supplying power to the load. That is, the main capacitor (Cm), connected in parallel with the 13V input power (Vs), can stably supply power to the load while maintaining a potential difference of 13V. The sub-capacitor (Cs) can perform the function of receiving power from the input power source (Vs), charging it, and then supplying power to the load. At this time, the voltage of the input power source (Vs) can be converted from 13V to 3.3V and applied to the sub-capacitor (Cs). Accordingly, the sub-capacitor (Cs) can stably supply power to the load while maintaining a potential difference of 3.3V. Although not shown in FIG. 4, the input power source (Vs) may be the output terminal of a DC / DC converter or the output terminal of a rectifier circuit that converts AC to DC. Additionally, an AC power supply, a PFC converter, a link capacitor, etc., may be connected prior to the DC / DC converter.

[0034] If a problem occurs in the input power (Vs) or the power supply system connected prior to the input power (Vs), causing the power supplied to the main power (Cm) and sub power (Cs) to be cut off (or interrupted), the voltage level of the main power (Cm) will gradually drop because the main power (Cm) will no longer receive power. At this time, the power supply unit (10) must ensure a minimum time for the load to back up data or record information required by the MCU (Micro Control Unit), as previously explained, this minimum time is referred to as the hold-up time in the industry.

[0035] The comparator (20) is a preset fault voltage (V) that is lower than the normal voltage of the main power supply (Cm) as the voltage of the main power supply (Cm) drops due to the power supplied to the main power supply (Cm) being cut off. PF It can perform the function of outputting a fault voltage arrival signal when it reaches ). In the example illustrated in Fig. 5, the normal voltage of the main power supply (Cm) is 13V, and the fault voltage (V PF ) is 10V. That is, since the main capacitor (Cm), which is the main power source (Cm), no longer receives power due to the power cutoff, the voltage level drops from 13V toward 10V as power is supplied to the load. Here, the point at which the power supplied to the main power source (Cm) is cut off is the time at T1.

[0036] The (+) terminal and output terminal of the amplifier of the comparator (20) are connected to a control unit (not shown). At this time, the fault arrival signal output from the comparator (20) is transmitted to the control unit, and accordingly, the control unit [transmits] the voltage of the main power supply (Cm) to the fault voltage (V PFIt can be determined that it has reached the point of power cutoff. The control unit drives the hold-up time extension circuit (30) when the time from the point of power cutoff to the point of reaching the fault voltage is shorter than the preset time. For example, if the preset time described above is 10ms, the hold-up time extension circuit (30) is driven only when the time from the point of power cutoff to the point of reaching the fault voltage is less than 10ms. In this example, the hold-up time of the power drive device is typically designed to ensure at least 50ms. However, when a situation different from the expected situation occurs at the time the power is cut off (for example, when the load on the load is heavier than expected), the power of the main capacitor (Cm) is consumed faster than usual, causing the hold-up time to be reduced to less than 50ms. At this time, the control unit drives the hold-up time extension circuit (30) to ensure that the hold-up time is at least 50ms. The driving time of the hold-up time extension circuit (30) is when the voltage of the main power supply (Cm) is the fault voltage (V PF A preset loss voltage (V) that is lower than ) and higher than the normal voltage of the sub-power supply (Cs). REG , it may be the point at which it reaches 3.3V (Regulator input Power Loss). In this example, the loss voltage may be 4.8V.

[0037] The hold-up time extension circuit (30) is connected in parallel to the sub-power supply (Cs). The hold-up time extension circuit (30) includes a first switch (31) connected to the output terminal of the sub-power supply (Cs), a second switch (32) connected to the first switch (31), and an extension capacitor (Ce) connected between the point where the first switch (31) and the second switch (32) are connected and the output terminal of the sub-power supply (Cs). The control unit controls the first switch (31) and the second switch (32) by transmitting signals to the gate terminal (G1) of the first switch (31) and the gate terminal (G2) of the second switch (32) connected to the control unit. When the power supply unit (10) is first operated, the control unit switches the first switch (31) on to charge the extension capacitor (Ce), and when charging is complete, switches the first switch (31) off to store power in the extension capacitor (Ce). Subsequently, the control unit cuts off the power supplied to the main power supply (Cm) from the point of interruption of the fault voltage (V PF If the time until the point of arrival is shorter than the preset time, the voltage of the main power supply (Cm) is the preset loss voltage (V REGWhen it reaches ), the second switch (32) is switched on to supply power stored in the expansion capacitor (Ce) to the load. At this time, the power that can be supplied to the load increases due to the power output from the expansion capacitor (Ce), and consequently, the effect of extending the hold-up time occurs. From the perspective of circuit elements, when the second switch (32) is switched on, the sub-capacitor (Cs) and the expansion capacitor (Ce) are connected in parallel, and accordingly, the effect of increasing the capacitance of the sub-capacitor (Cs) occurs. As explained earlier through FIG. 3, it is usually impossible to increase the size of the sub-capacitor (Cs) in a PCB that has already been compactly designed. However, according to the present invention, it is possible to achieve the effect of extending the hold-up time while maintaining the capacitance of the sub-capacitor (Cs). Since the hold-up time extension circuit (30) according to the present invention can be placed by finding a suitable empty space in the already designed PCB circuit, the problem of having to completely redo the circuit layout design of the PCB to secure space for increasing the capacitance of the sub-capacitor (Cs) can be solved.

[0038] Referring to FIG. 5, a power supply device (200) having a hold-up time extension function according to the present invention will be described in more detail.

[0039] The upper graph (50) of FIG. 5 shows the change in voltage of the main power supply (Cm) when power is cut off, and the lower graph (55) shows the change in voltage of the sub power supply (Cs). Here, the normal voltage of the main power supply (Cm) is 13V in this example as a DC voltage. Also, the normal voltage of the sub power supply (Cs) is 3.3V in this example as a DC voltage. When the power supplied to the main power supply (Cm) is cut off (Power loss), the voltage level of the main power supply (Cm) gradually decreases. The point of power loss is the time of T1. As the voltage level of the main power supply (Cm) gradually decreases, a preset fault voltage (V) lower than the normal voltage is reached. PF When it reaches 10V, the comparator (20) outputs a fault voltage arrival signal to the control unit. Here, the fault voltage (V PF The point of arrival becomes the end point of T1 and the start point of T2. Even if the power is cut off, the normal voltage of the sub-power (Cs) (e.g., 3.3V) is maintained for a while because the main power (Cm) supplies power to the sub-power (Cs). However, as the voltage level of the main power (Cm) drops further, the loss voltage (V REG When it reaches 4.8V, the power supply from the main power source (Cm) to the sub power source (Cs) is interrupted. Here, the voltage loss (V REGThe point of arrival of ) becomes the end point of T2 and the start point of T3. When power supply from the main power source (Cm) to the sub-power source (Cs) is interrupted, the voltage level of the sub-power source (Cs), which was maintained at a normal voltage of 3.3V, gradually decreases. The point of arrival at which the voltage level of the sub-power source (Cs) gradually decreases and reaches a preset minimum voltage of 1.7V, which is lower than the normal voltage, becomes the end point of T3. However, if a preset condition according to the present invention is satisfied (when the time from the point of interruption of power supplied to the main power source (Cm) to the point of arrival of the fault voltage is shorter than the preset time), the hold-up time extension circuit (30) is driven, and accordingly, the time for the voltage level of the sub-power source (Cs) to drop from the normal voltage of 3.3V to the minimum voltage of 1.7V is extended by T4. Accordingly, the hold-up time increases to T1+T2+T3+T4. That is, when the load on the additional component is greater than expected and the hold-up time becomes shorter than the time typically required, the hold-up time extension circuit (30) according to the present invention is driven to extend the hold-up time to T1+T2+T3+T4, thereby allowing the hold-up time to be reset to meet the typical requirements. Additionally, the length of T4 can be adjusted by changing the capacitance of the extension capacitor (Ce).

[0041] The preferred embodiments of the present invention described above are disclosed for illustrative purposes only, and those skilled in the art with ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following claims. Explanation of the symbols

[0042] 10: Power supply 20 : Comparison section 30: Hold-up time extension circuit 31: First switch 32 : Second switch Vs : Input power Cm: Main power supply, main capacitor Cs: Sub power supply, sub capacitor Ce: Expansion capacitor G1: Gate terminal of the first switch (31) G2: Gate terminal of the first switch (32)

Claims

Claim 1 A power supply device having a hold-up time extension function, comprising: a power supply unit including a main power supply and a sub power supply that supplies power to a load; a comparator unit that outputs a fault voltage arrival signal when the voltage of the main power supply reaches a preset fault voltage lower than the normal voltage of the main power supply as the power supplied to the main power supply is cut off and the voltage of the main power supply drops; a hold-up time extension circuit connected in parallel to the sub power supply; and a control unit that drives the hold-up time extension circuit when the time from the point of power supply to the main power supply being cut off to the point of the fault voltage arrival is shorter than a preset time. Claim 2 A power supply device having a hold-up time extension function according to claim 1, wherein the hold-up time extension circuit comprises: a first switch connected to the output terminal of the sub-power supply; a second switch connected to the first switch; and an extension capacitor connected between the point where the first switch and the second switch are connected and the output terminal of the sub-power supply. Claim 3 A power supply device having a hold-up time extension function, wherein, in paragraph 2, the control unit switches on the first switch to charge the expansion capacitor during the initial operation of the power supply unit. Claim 4 A power supply device for extending hold-up time according to claim 3, wherein if the time from the point of interruption of power supplied to the main power source to the point of reaching the fault voltage is shorter than a preset time, the control unit switches on the second switch to output the power charged in the expansion capacitor. Claim 5 A power supply device for extending hold-up time according to claim 4, characterized in that when the voltage of the main power supply reaches a preset loss voltage that is lower than the fault voltage and higher than the normal voltage of the sub power supply, the control unit switches on the second switch. Claim 6 A power supply device for extending hold-up time according to claim 1, characterized in that the main power source is a main capacitor that receives power from an input power source, charges it, and then supplies power to a load. Claim 7 A power supply device for extending hold-up time, characterized in that, in claim 1, the sub-power supply is a sub-capacitor that is charged by receiving power from an input power supply. Claim 8 A power supply device for extending hold-up time according to claim 7, characterized in that when the voltage of the main power supply reaches a preset loss voltage that is lower than the fault voltage and higher than the normal voltage of the sub power supply, the power supply from the main power supply to the sub power supply is interrupted.

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