Power supply circuit and electronic system

Abstract

The invention discloses a power supply circuit and an electronic system. The power supply circuit comprises a load switch, a first energy storage capacitor, a bidirectional direct current-direct current converter and a second energy storage capacitor, in a first mode, the first energy storage capacitor supplies power to a load at an output end, but the voltage of the first energy storage capacitor is difficult to maintain normal work of the load and can only play a buffering role; and at the moment, the second energy storage capacitor supplies power to the load through the bidirectional DC-DC converter and the bypass circuit, so that power supply to the load can be continuously realized, and power failure cannot be caused.

Description

Technical Field

[0001] This invention relates to power electronics technology, specifically to power supply circuits and electronic systems. Background Technology

[0002] Electronic products generally require a continuous power supply during use. When the input voltage drops, the power supply circuit cannot provide power, necessitating the storage of reserve energy to power the electronic product for a certain period to complete data storage. Taking solid-state drives (SSDs) as an example, SSDs are hard drives made of solid-state electronic storage chip arrays. During operation, they require a continuous power supply to ensure data reading, writing, and storage. However, when the input voltage drops or the load suddenly increases, causing the load switch to limit current, the power supply voltage drops, preventing the SSD from storing data in time, potentially leading to data loss. To solve this problem, existing technology typically adds multiple capacitors to the load side of the power supply circuit to maintain power to the load, thereby extending the time of power supply to the load after a power outage or current limiting.

[0003] like Figure 1 As shown, this is the power supply circuit of a solid-state drive in the prior art. The power supply circuit receives an input voltage V at its input terminal. in The power supply voltage V is output through the load switch. out The load is supplied with power, and multiple energy storage capacitors (C0, C1...C1) are connected in parallel at the load end. n In the event of a power outage or a sudden increase in load causing current limiting by the load switch, the energy storage capacitor can maintain power supply to the load for a period of time. In this embodiment, the power supply circuit also includes an input capacitor C connected to the input terminal. in This type of power supply circuit is used to filter the input voltage. However, due to the addition of multiple energy storage capacitors, this power supply circuit increases the size of the product, which is not conducive to the miniaturization of the circuit. It also suffers from high cost and low efficiency. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a power supply circuit and an electronic system to solve the problems of large size, high cost and low efficiency of power supply circuits in the prior art.

[0005] According to a first aspect of the present invention, a power supply circuit is provided, the power supply circuit receiving an input voltage at an input terminal and generating a power supply voltage at an output terminal to supply power to a load, the power supply circuit comprising:

[0006] A load switch is coupled between the input and output terminals of the power supply circuit;

[0007] The first energy storage capacitor is coupled to the output terminal of the power supply circuit;

[0008] A bidirectional DC-DC converter includes a first terminal coupled to the output terminal of the power supply circuit and a second terminal connected to the energy storage voltage;

[0009] A bypass circuit is coupled between the first and second terminals of the bidirectional DC-DC converter; and

[0010] The second energy storage capacitor is coupled to the second terminal of the bidirectional DC-DC converter;

[0011] In the first mode, the load switch is turned off, and the energy storage voltage charges the first energy storage capacitor via the bypass circuit to supply power to the load.

[0012] Preferably, in the second mode, the input voltage charges the first energy storage capacitor via the load switch to supply power to the load, while the DC-DC converter performs power conversion on the supply voltage to charge the second energy storage capacitor.

[0013] Preferably, in the second mode, the DC-DC converter operates in buck mode to charge the second energy storage capacitor.

[0014] Preferably, when the reference value of the supply voltage is not greater than the energy storage voltage, the bypass circuit is enabled, and the energy storage voltage charges the first energy storage capacitor through the bypass circuit until the supply voltage drops to its reference value.

[0015] Preferably, when the reference value of the supply voltage is greater than the energy storage voltage, the bypass circuit is not enabled, and the energy storage voltage charges the first energy storage capacitor via the bidirectional DC-DC converter.

[0016] In the first mode, when the supply voltage drops to the energy storage voltage, the bypass circuit is enabled, and the energy storage voltage charges the first energy storage capacitor via the bypass circuit to supply power to the load.

[0017] Preferably, in the first mode, when the supply voltage drops to its reference value, the energy storage voltage charges the first energy storage capacitor via the bidirectional DC-DC converter to supply power to the load.

[0018] Preferably, the bidirectional DC-DC converter operates in boost mode.

[0019] Preferably, the power supply circuit includes:

[0020] A protection circuit is coupled between the first terminal of the bidirectional DC-DC converter and the output terminal of the power supply circuit. The protection circuit cuts off the path between the power supply voltage and the energy storage voltage when a short circuit occurs in the power supply circuit.

[0021] Preferably, the load switch includes two power switching transistors connected in reverse series, and the load switch is turned off in the first mode.

[0022] Preferably, the power supply circuit includes a load switch control circuit, which samples the power supply voltage and compares the sampled value of the power supply voltage with a reference voltage to generate a feedback compensation signal, which is used to control the load switch.

[0023] Preferably, the bypass circuit includes:

[0024] A switching transistor, the first terminal of which is connected to the first terminal of the bidirectional DC-DC converter, and the second terminal of which is connected to the second terminal of the bidirectional DC-DC converter.

[0025] According to a second aspect of the present invention, an electronic system is provided, comprising:

[0026] Load; and

[0027] As described in any of the first aspects, the load is connected to the output of the power supply circuit to receive the power supply voltage.

[0028] The power supply circuit of the technical solution of this invention includes a load switch and a first energy storage capacitor, a bidirectional DC-DC converter and a second energy storage capacitor. In the first mode, the first energy storage capacitor supplies power to the load at the output end, but the voltage of the first energy storage capacitor is difficult to maintain the normal operation of the load and can only play a buffering role to prevent the load at the output end from completely losing power. At this time, the second energy storage capacitor supplies power to the load through the bidirectional DC-DC converter and the bypass circuit, so that the power supply to the load can be continuously realized without causing a power outage. Attached Figure Description

[0029] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0030] Figure 1 The diagram shown is a circuit diagram of the power supply circuit of a solid-state drive in the prior art;

[0031] Figure 2 The diagram shown is a circuit diagram of the power supply circuit according to the first embodiment of the present invention;

[0032] Figure 3 The diagram shown is a circuit diagram of the power supply circuit according to the second embodiment of the present invention;

[0033] Figure 4 The diagram shown is a circuit diagram of the load switch control circuit according to an embodiment of the present invention.

[0034] Figure 5 The diagram shown is a circuit diagram of the power supply circuit according to the third embodiment of the present invention;

[0035] Figure 6 The diagram shown is a waveform diagram of the power supply circuit in an embodiment of the present invention. Detailed Implementation

[0036] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0037] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0038] Furthermore, it should be understood that in the following description, "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by electrical or electromagnetic connections. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it can be directly coupled or connected to another element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected" to another element, it means that there are no intermediate elements between them.

[0039] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0040] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0041] Figure 2 The diagram shown is a circuit diagram of a power supply circuit according to a first embodiment of the present invention. This power supply circuit includes a circuit for receiving input voltage V. in The input terminal and the generated supply voltage V out The output terminal, load switch 20, and first energy storage capacitor C0 are connected. Load switch 20 is connected between the input and output terminals of the power supply circuit, and first energy storage capacitor C0 is connected between the output terminal of the power supply circuit and reference ground. The input voltage V inThe first energy storage capacitor C0 is charged via the load switch 20, thereby supplying power to the load. In this embodiment, the power supply circuit also includes an input capacitor C. in Input capacitor C in Connected to the input terminal of the power supply circuit, used to regulate the input voltage V. in It serves to filter and stabilize voltage.

[0042] This embodiment's power supply circuit includes a bidirectional DC-DC converter 21, a bypass circuit 22, and a second energy storage capacitor C1. The first terminal of the bidirectional DC-DC converter 21 is coupled to the output terminal of the power supply circuit, and the second terminal is connected to the energy storage voltage CSTR. The second energy storage capacitor C1 is connected to the second terminal of the bidirectional DC-DC converter 21. The bypass circuit 22 is connected between the first and second terminals of the bidirectional DC-DC converter 21. In the first mode, the load switch 20 is open, and the energy storage voltage CSTR charges the first energy storage capacitor C0 via the bypass circuit 22 to supply power to the load. In this embodiment, the first mode refers to the operating mode when the input voltage cannot supply power to the load due to a power supply circuit failure, such as when the input voltage drops or when the load switch limits current due to a heavy load. In one implementation, the power supply circuit determines the current operating mode by detecting when the input voltage drops to zero or to a certain level. In the first mode, the load switch is off, the input voltage cannot provide power to the load, and the power supply circuit needs the backup power from the second energy storage capacitor to maintain power supply to the load.

[0043] In this embodiment, when the power supply circuit operates in the second mode, the input voltage V in The first energy storage capacitor C0 is charged via load switch 20 to supply power to the load, and the bidirectional DC-DC converter 21 supplies power to the supply voltage V. out The power conversion generates an energy storage voltage CSTR to charge the second energy storage capacitor C1. The energy stored in the second energy storage capacitor C1 serves as backup energy for the load. The second mode refers to the operating mode when the power supply circuit is working normally. In this mode, the input voltage supplies power to the load via the load switch, and simultaneously generates an energy storage voltage via a bidirectional DC-DC converter to charge the second energy storage voltage.

[0044] In one embodiment, in a first mode, when the reference value of the supply voltage is not greater than the energy storage voltage CSTR, the bypass circuit 22 is enabled, and the energy storage voltage CSTR charges the first energy storage capacitor C0 via the bypass circuit 22 until the energy storage voltage CSTR reaches the reference value of the supply voltage. When the reference value of the supply voltage is greater than the energy storage voltage CSTR, the bypass circuit is not enabled, and the energy storage voltage CSTR charges the first energy storage capacitor C0 via the bidirectional DC-DC converter 21 to maintain continuous power supply to the load.

[0045] In another embodiment, when the power supply circuit operates in the first mode, the first energy storage capacitor C0 supplies power to the load. When the supply voltage drops to the energy storage voltage CSTR, the second energy storage capacitor supplies power to the load via a bypass circuit to maintain continuous power supply to the load. When the supply voltage drops to its reference value, the bidirectional DC-DC converter 21 performs power conversion on the energy storage voltage CSTR to charge the first energy storage capacitor C0, thereby maintaining power supply to the load. In this embodiment, the load switch is unidirectional. In normal circuit operation, i.e., the second mode, it is through-current; in the first mode, the load switch is reverse-biased and blocks power. The load switch includes two reverse-connected power switching transistors, i.e., connected back-to-back, with their sources connected to each other and their drains connected to the input and output terminals of the power supply circuit, respectively. The load switch can be a MOSFET. Figure 2 Although only an example of using two P-type MOSFETs in reverse series for the load switch is given, it can also be achieved using two N-type MOSFETs in reverse series. The control terminals of the two power switches can be controlled separately, or the control terminals of the two power switches can be connected together as a single control terminal. Figure 2 The diagram illustrates a scenario where two control terminals are connected together as a single control terminal.

[0046] In one embodiment, when the supply voltage V out When the reference value is not greater than the energy storage voltage CSTR, in the first mode, the energy storage voltage CSTR charges the first energy storage capacitor C0 through the bypass circuit 22 to maintain continuous power supply to the load. When the supply voltage V out When the voltage drops to the reference value, the bidirectional DC-DC converter uses boost mode to charge the first energy storage capacitor C1, maintaining the supply voltage at the reference value. In the second mode, the input voltage V... in The load is powered through the load switch 20, and the first energy storage capacitor C0 is charged at the same time. The bidirectional DC-DC converter 21 uses the buck working mode to charge the second energy storage capacitor C1.

[0047] In this embodiment, in the first mode, for example, at the input voltage V in In the event of a power outage or current limiting due to a heavy load switch, the first energy storage capacitor C0 supplies power to the output load. However, the voltage of the first energy storage capacitor C0 is insufficient to maintain the normal operation of the load; it only serves as a buffer to prevent the output load from completely losing power. At this time, the second energy storage capacitor C1 supplies power to the output load after being boosted by a bidirectional DC-DC converter, with the supply voltage V... out When the reference value is less than the energy storage voltage CSTR, the second energy storage capacitor C1 first supplies power to the load through the bypass circuit. When the supply voltage V outWhen the voltage drops to the reference value, the second energy storage capacitor C1 is boosted by the bidirectional DC-DC converter to supply power to the output load, thus enabling continuous power supply to the load without causing a power outage.

[0048] In one embodiment, the second energy storage capacitor C1 is a supercapacitor with a large capacitance value, which facilitates energy storage. To reduce the inrush current of the second energy storage capacitor C1, a disconnecting switch can be connected in series before C1. It should be understood that the disconnecting switch can be, but is not limited to, a power switching transistor.

[0049] In this embodiment, the power supply circuit can be used in an electronic system, which includes a load and the power supply circuit in this embodiment. The load is connected to the output terminal of the power supply circuit to receive the power supply voltage.

[0050] Figure 3 The diagram shown is a circuit diagram of the power supply circuit according to a second embodiment of the present invention. Figure 2 Compared to the illustrated embodiment, this embodiment adds a protection circuit 30 to the power supply circuit. The protection circuit 30 is connected to the output terminal of the power supply circuit and the first terminal of the bidirectional DC-DC converter, and is used to cut off the power supply voltage V when a short circuit occurs in the power supply circuit. out The path between the energy storage voltage CSTR and the circuit is designed to improve circuit safety.

[0051] Figure 4 The diagram shown is a circuit diagram of a load switch control circuit according to an embodiment of the present invention. This load switch control circuit 40 is used to control the on and off states of the load switch 20. Figure 4 The load switch control circuit 40 shown includes an error amplifier gm1 and a compensation circuit. One input of the error amplifier gm1 acquires the voltage at the output of the load switch, and the other input receives a reference voltage V. ref1 The compensation circuit consists of resistor R1 and capacitor C. V1 The series connection consists of resistor R1 connected to the output terminal of error amplifier gm1, and capacitor C. V1 Grounding, resistor R1 and capacitor C V1 The positions of the components are interchangeable. The error amplifier gm1 outputs a feedback compensation signal to the control terminal of the load switch, thereby adjusting the operating state of the load switch and thus providing overvoltage protection. The above is just a specific example of a load switch control circuit, but it is not limited to the above circuit structure. For example, the compensation circuit described above may only include a capacitor, or a resistor and a capacitor in parallel; the overvoltage protection circuit may also be implemented using an operational amplifier, and so on. Figure 4 In the diagram, the feedback compensation signal is directly connected to the control terminal of the load switch. However, in practical applications, the feedback compensation signal is generally connected to the control terminal through a drive circuit. The drive circuit is familiar to those skilled in the art and is therefore omitted from the diagram.

[0052] Figure 5 The diagram shown is a circuit diagram of the power supply circuit according to the third embodiment of the present invention. Figure 5 As shown, the load switch 20 includes power switches MA and MB connected in series, which are connected between the input and output terminals of the power supply circuit. In this embodiment, the protection circuit is configured as transistor M1. Transistor M1 is connected between the output terminal of the power supply circuit and the first terminal of the bidirectional DC-DC converter to provide circuit protection. For example, when a short circuit occurs at the output terminal of the power supply circuit, transistor M1 turns off, and the path between the output terminal of the power supply circuit and the first terminal of the bidirectional DC-DC converter is cut off, that is, the path between the supply voltage and the energy storage voltage is cut off, thereby improving circuit safety performance.

[0053] In this embodiment, the bypass circuit includes a switching transistor M4. The first terminal of the switching transistor M4 is connected to the first terminal of the bidirectional DC-DC converter, and the second terminal is connected to the second terminal of the bidirectional DC-DC converter. The first-mode energy storage voltage CSTR charges the first energy storage capacitor C0 via the switching transistor M4 to maintain power supply to the load. The bypass circuit also includes a capacitor C2 connected to the first terminal of the switching transistor M4 to maintain voltage stability at that terminal.

[0054] In one embodiment, when the supply voltage V out When the reference value is not greater than the energy storage voltage CSTR, the energy storage voltage CSTR charges the first energy storage capacitor C0 through the switching transistor M4 to maintain power supply to the load.

[0055] In this embodiment, the bidirectional DC-DC converter includes power transistors M2 and M3, an inductor L, and an output capacitor C. Power transistors M2 and M3 are connected in series between transistor M1 and reference ground. One end of the inductor L is connected to the common connection point of power transistors M2 and M3, and the other end is connected to the output capacitor C. In the first mode, when the bidirectional DC-DC converter operates in boost mode, power transistor M3 acts as the main power switch, and power transistor M2 acts as the synchronous switch. In the second mode, when the bidirectional DC-DC converter operates in buck mode, power transistor M2 acts as the main power switch, and power transistor M3 acts as the synchronous switch. Power transistors M2 and M3 are driven by a drive circuit to periodically turn on and off. The drive circuit is familiar to those skilled in the art and is therefore omitted in the figure.

[0056] Figure 6 The diagram shown is a waveform diagram of the power supply circuit in an embodiment of the present invention. Figure 6 The input voltage V is shown in sequence. in Power supply voltage V out The energy storage voltage CSTR and the control signal G of the switching transistor M4. M4 In this embodiment, the supply voltage Vout The reference value is not greater than the energy storage voltage CSTR, and the bypass circuit includes the switching transistor M4.

[0057] At time t0, the input voltage V in When power is lost, the power supply circuit operates in the first mode. In the first mode, the load switch is turned off, and the supply voltage V out The load is supplied with power, and the voltage begins to decrease slowly. At time t1, the supply voltage V... out The voltage drops to equal the energy storage voltage CSTR, and the control signal G... M4 When the switch is switched to the active level, the switching transistor M4 is turned on, and the energy storage voltage CSTR charges the first energy storage capacitor through the switching transistor M4 to maintain power supply to the load. From time t1, the supply voltage V out The energy storage voltage CSTR drops simultaneously when the supply voltage V out When it drops to its reference value, the control signal G M4 When the signal is switched to an inactive level, switching transistor M4 is turned off, and the energy storage voltage CSTR charges the first energy storage capacitor via the bidirectional DC-DC converter. At this time, the bidirectional DC-DC converter operates in boost mode to maintain the supply voltage V. out Maintain the supply voltage at the reference value.

[0058] The power supply circuit of this embodiment includes a load switch and a first energy storage capacitor, a bidirectional DC-DC converter and a second energy storage capacitor. In the first mode, the first energy storage capacitor supplies power to the load at the output end, but the voltage of the first energy storage capacitor is difficult to maintain the normal operation of the load and can only play a buffering role to prevent the load at the output end from completely losing power. At this time, the second energy storage capacitor supplies power to the load through the bidirectional DC-DC converter and the bypass circuit, so that the power supply to the load can be continuously realized without causing a power outage.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A power supply circuit, wherein the power supply circuit receives an input voltage at its input terminal and generates a power supply voltage at its output terminal to supply power to a load, characterized in that, include: A load switch is coupled between the input and output terminals of the power supply circuit; The first energy storage capacitor is coupled to the output terminal of the power supply circuit; A bidirectional DC-DC converter includes a first terminal coupled to the output terminal of the power supply circuit and a second terminal connected to the energy storage voltage; A bypass circuit is coupled between the first and second terminals of the bidirectional DC-DC converter; and The second energy storage capacitor is coupled to the second terminal of the bidirectional DC-DC converter; In the first mode, the load switch is turned off, and the energy storage voltage charges the first energy storage capacitor via the bypass circuit to supply power to the load.

2. The power supply circuit according to claim 1, characterized in that, In the second mode, the input voltage charges the first energy storage capacitor via the load switch to supply power to the load, while the DC-DC converter performs power conversion on the supply voltage to charge the second energy storage capacitor.

3. The power supply circuit according to claim 2, characterized in that, In the second mode, the DC-DC converter operates in buck mode to charge the second energy storage capacitor.

4. The power supply circuit according to claim 1, characterized in that, When the reference value of the supply voltage is not greater than the energy storage voltage, the bypass circuit is enabled, and the energy storage voltage charges the first energy storage capacitor through the bypass circuit until the supply voltage drops to its reference value.

5. The power supply circuit according to claim 1, characterized in that, When the reference value of the supply voltage is greater than the energy storage voltage, the bypass circuit is not enabled, and the energy storage voltage charges the first energy storage capacitor via the bidirectional DC-DC converter.

6. The power supply circuit according to claim 4, characterized in that, In the first mode, when the supply voltage drops to the energy storage voltage, the bypass circuit is enabled, and the energy storage voltage charges the first energy storage capacitor via the bypass circuit to supply power to the load.

7. The power supply circuit according to claim 6, characterized in that, In the first mode, when the supply voltage drops to its reference value, the energy storage voltage charges the first energy storage capacitor via the bidirectional DC-DC converter to supply power to the load.

8. The power supply circuit according to claim 7, characterized in that, The bidirectional DC-DC converter operates in boost mode.

9. The power supply circuit according to claim 1, characterized in that, The power supply circuit includes: A protection circuit is coupled between the first terminal of the bidirectional DC-DC converter and the output terminal of the power supply circuit. The protection circuit cuts off the path between the power supply voltage and the energy storage voltage when a short circuit occurs in the power supply circuit.

10. The power supply circuit according to claim 1, characterized in that, The load switch includes two power switching transistors connected in reverse series, and the load switch is turned off in the first mode.

11. The power supply circuit according to claim 1, characterized in that, The power supply circuit includes a load switch control circuit, which samples the power supply voltage and compares the sampled value of the power supply voltage with a reference voltage to generate a feedback compensation signal, which is used to control the load switch.

12. The power supply circuit according to claim 1, characterized in that, The bypass circuit includes: A switching transistor, the first terminal of which is connected to the first terminal of the bidirectional DC-DC converter, and the second terminal of which is connected to the second terminal of the bidirectional DC-DC converter.

13. An electronic system comprising: load; as well as In any one of claims 1-12, the load is connected to the output terminal of the power supply circuit to receive the power supply voltage.

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