Charging circuit and BST chip

Abstract

The utility model provides a charging circuit and a BST chip, the charging circuit comprises at least two charging branches, a sampling circuit and a driving circuit, and different charging branches are connected to power supply ends of different voltage levels; the sampling circuit is used for sampling power supply voltage and outputting sampling voltage; the driving circuit determines a corresponding power supply end based on the sampling voltage, and drives the charging branch circuit corresponding to the power supply end to be connected with one end of the capacitor. According to the charging circuit, the sampling circuit detects the power supply voltage and then outputs the sampling voltage to the driving circuit, and the driving circuit determines the voltage matched with the sampling voltage in the voltages of all the power supply ends and drives the charging branch circuit corresponding to the power supply end and the capacitor to form a closed loop. And the power supply end charges the capacitor through the corresponding charging branch. According to the utility model, the adaptive charging branch can be rapidly switched to charge the capacitor based on the change of the power supply voltage, the power supply efficiency and the response speed of the chip are improved, and the work of the chip is not influenced.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, and in particular to a charging circuit and a BST chip. Background Art

[0002] In circuit design, the BST (Buck Switching Regulator) chip is a step-down switching regulator chip, commonly used in the field of power management. The chip uses multiple voltage sources for power supply, and the voltage domains are multiple and not unique, which means that the chip cannot use a single power supply to charge the internal capacitor. It is necessary to select a suitable internal voltage first, and then process the internal voltage before charging the capacitor, resulting in low power supply efficiency and slow response speed of the BST chip. Utility Model Content

[0003] The utility model aims to provide a charging circuit and a BST chip to solve the problem that the BST chip has multiple and complex internal voltage domains, resulting in low power supply efficiency and slow response speed of the chip.

[0004] In order to solve the above technical problems, based on one aspect of the present utility model, the present utility model provides a charging circuit, which includes:

[0005] At least two charging branches, different charging branches are connected to power supply terminals of different voltage levels;

[0006] A sampling circuit, wherein the sampling circuit is used to sample the power supply voltage and output the sampled voltage;

[0007] A driving circuit connected to the sampling circuit determines the corresponding power supply end based on the sampling voltage, and drives the charging branch corresponding to the power supply end to connect with one end of the capacitor, thereby forming a closed loop.

[0008] Optionally, the charging circuit includes two charging branches, namely a first charging branch and a second charging branch; the driving circuit drives the first charging branch and the capacitor to form a closed loop when the sampling voltage is greater than the reference voltage, and the driving circuit drives the second charging branch and the capacitor to form a closed loop when the sampling voltage is less than or equal to the reference voltage.

[0009] Optionally, the power supply end corresponding to the first charging branch provides a first power supply voltage, and the power supply end corresponding to the second charging branch provides a second power supply voltage, and the second power supply voltage is greater than the first power supply voltage.

[0010] Optionally, the charging branch includes a switching element, the switching element having a first voltage end, a second voltage end and a driving end, the first voltage end of the switching element is connected to the corresponding power supply end, the second voltage end of the switching element is connected to the capacitor, and the driving end of the switching element is coupled to the driving circuit.

[0011] Optionally, the switch element includes one or a combination of at least two of a logic switch, a relay, a photocoupler and a transistor.

[0012] Optionally, the switch elements of the first charging branch and the second charging branch are both transistors.

[0013] Optionally, the driving circuit includes a comparator, one input of the comparator is connected to the sampling circuit, the other input of the comparator is connected to the reference voltage, and the output of the comparator is coupled to the switch element of the first charging branch and the switch element of the second charging branch.

[0014] Optionally, the driving circuit further includes an inverter and a driver, the input end of the inverter is connected to the output end of the comparator, the output end of the inverter is connected to the driver, and the driver is connected to the switch element of the first charging branch.

[0015] Optionally, the driver comprises a linear regulator.

[0016] Optionally, the sampling circuit includes a first resistor and a second resistor, one end of the second resistor is connected to the power supply voltage, the other end of the second resistor is connected to the drive circuit, and the other end of the second resistor is also grounded through the first resistor.

[0017] Based on another aspect of the utility model, the utility model further provides a BST chip, which includes a capacitor and the charging circuit as described above, and the charging branch of the charging circuit is grounded through the capacitor.

[0018] In the charging circuit and BST chip provided by the utility model, the charging circuit includes at least two charging branches, a sampling circuit and a driving circuit, and different charging branches are connected to power supply terminals of different voltage levels; the sampling circuit is used to sample the power supply voltage and output the sampling voltage; the driving circuit determines the corresponding power supply terminal based on the sampling voltage, and drives the charging branch corresponding to the power supply terminal and the capacitor to form a closed loop. In this way, after the power supply voltage is detected by the sampling circuit, a sampling voltage is output to the driving circuit, and the driving circuit determines the voltage that matches the sampling voltage among the voltages of all power supply terminals, and drives the charging branch corresponding to the power supply terminal and the capacitor to form a closed loop, thereby allowing the power supply terminal to charge the capacitor through the corresponding charging branch. The utility model can quickly switch the adapted charging branch to charge the capacitor based on the change of the power supply voltage, thereby improving the power supply efficiency and response speed of the chip, and has no effect on the operation of the chip.

[0019] It should be noted that, since the BST chip includes the charging circuit, it also has the technical effects brought by the charging circuit, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Those skilled in the art should understand that the drawings provided are for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0021] Figure 1 is a schematic diagram of a charging circuit of an embodiment of the utility model;

[0022] Figure 2 It is another schematic diagram of a charging circuit according to an embodiment of the present invention.

[0023] In the attached figure:

[0024] 10-sampling circuit; 20-comparison circuit; 30-charging branch;

[0025] Q-switching element; Q1-first switching element; Q2-second switching element; U1-inverter; U2-driver; CMP-comparator; R1-first resistor; R2-second resistor; C-capacitor. DETAILED DESCRIPTION

[0026] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0027] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the term "at least two" is usually used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "the proximal end" and "the distal end" generally refer to two corresponding parts, which not only include the endpoints, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in the present invention, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element may be in any orientation such as inside, outside, above, below or on one side of another element, unless otherwise clearly indicated in the content. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] Figure 1 Schematic diagram of a charging circuit according to an embodiment of the present invention. Figure 1, this embodiment schematically provides a charging circuit applied to a BST chip, the charging circuit includes a sampling circuit 10, a comparison circuit 20 connected to the sampling circuit 10, and multiple charging branches 30 connected in parallel between the comparison circuit 20 and the capacitor C, and the capacitor C is grounded. Different charging branches 30 are connected to power supply terminals (voltage sources) of different voltage levels, that is, different power supply terminals provide different power supply voltages. The sampling circuit 10 is used to sample the power supply voltage input into the chip, so as to output the sampled voltage of the power supply voltage to the driving circuit. The driving circuit determines the corresponding power supply terminal based on the sampled voltage, thereby selecting the power supply terminal adapted to the sampled voltage, and drives the charging branch 30 corresponding to the power supply terminal to connect with the capacitor C, thereby forming a closed loop, and then charging the capacitor C. In this way, after the sampling circuit 10 detects the power supply voltage, a sampling voltage is output to the driving circuit. The driving circuit determines the voltage adapted to the sampling voltage among the voltages of all power supply terminals, and drives the charging branch 30 corresponding to the power supply terminal to form a closed loop with the capacitor C, so that the power supply terminal charges the capacitor C through the corresponding charging branch 30. The utility model can quickly switch the adapted charging branch 30 to charge the capacitor C based on the change of the power supply voltage, thereby improving the power supply efficiency and response speed of the chip without affecting the operation of the chip.

[0029] Figure 2 is another schematic diagram of a charging circuit according to an embodiment of the present invention. Figure 2 The sampling circuit 10 includes a first resistor R1 and a second resistor R2, one end of the second resistor R2 is connected to the power supply voltage, the other end of the second resistor R2 is connected to the driving circuit, and the other end of the second resistor R2 is also grounded through the first resistor R1. In this way, the sampling voltage is the divided voltage obtained by dividing the power supply voltage by the first resistor R1.

[0030] This embodiment does not limit the specific structure of each charging branch 30. For example, the charging branch 30 includes a switch element Q, the switch element Q has a first voltage terminal, a second voltage terminal and a driving terminal, the first voltage terminal of the switch element Q is connected to the corresponding power supply terminal, the second voltage terminal of the switch element Q is connected to the capacitor C, the driving terminal of the switch element Q is coupled to the driving circuit, and the driving circuit outputs a driving signal to the switch element Q of each charging branch 30 after receiving the sampling voltage, thereby driving the switch element Q of the charging branch 30 corresponding to the power supply terminal adapted to the sampling voltage to conduct, so that the charging branch 30 is a passage, thereby connecting the corresponding power supply terminal and the capacitor C to charge the capacitor C, and the driving signal of the driving circuit drives the switch elements Q of the remaining charging branches 30 to close, so that the remaining charging branches 30 are open circuits, and the electrical connection between the power supply terminal and the capacitor C is disconnected.

[0031] For example, the switch element Q includes one or a combination of at least two of a logic switch, a relay, a photocoupler, and a transistor, such as a triode or a MOS transistor.

[0032] See below Figure 2 The charging circuit of the present utility model is described exemplarily.

[0033] The charging circuit includes two charging branches 30, namely a first charging branch and a second charging branch. The voltage provided by the power supply end connected to the first charging branch is a first power supply voltage V1, and the voltage provided by the power supply end connected to the second charging branch is a second power supply voltage V2, and V2 is greater than V1. Optionally, the second power supply voltage can be a modulated voltage of the power supply voltage; the first power supply voltage can be a modulated voltage of the power supply voltage, or the output voltage of an internal linear regulator inside the chip, or other power supply voltage. When the sampling voltage is greater than the reference voltage, the driving circuit drives the first charging branch to form a closed loop with the capacitor C, and charges the capacitor C through V1, and when the sampling voltage is less than or equal to the reference voltage, the driving circuit drives the second charging branch to form a closed loop with the capacitor C, and charges the capacitor C through V2. It should be noted that the value of the reference voltage here is equal to the value of V1.

[0034] Further, the switching element Q of the first charging branch is the first switching element Q1, and the switching element Q of the second charging branch is the second switching element Q2, that is, the driving circuit drives the first switching element Q1 to turn on and drives the second switching element Q2 to turn off when the sampling voltage is greater than the reference voltage, so that the first charging branch connects V1 and the capacitor C, and the driving circuit drives the second switching element Q2 to turn on and drives the first switching element Q1 to turn off when the sampling voltage is less than or equal to the reference voltage, so that the second charging branch connects V2 and the capacitor C.

[0035] Preferably, the first switch element Q1 and the second switch element Q2 are both transistors, and the types of the transistors are different. Selecting transistors can increase the turn-off speed and facilitate the rapid switching of the charging branch 30. For example, the first switch element Q1 and the second switch element Q2 are both MOS tubes, the first switch element Q1 is an NMOS tube, the drain of the first switch element Q1 is connected to V1, the source of the first switch element Q1 is connected to the capacitor C, and the gate of the first switch element Q1 is connected to the drive circuit; the second switch element Q2 is a PMOS tube, the drain of the second switch element Q2 is connected to V2, the source of the second switch element Q2 is connected to the capacitor C, and the gate of the second switch element Q2 is connected to the drive circuit. The first switch element Q1 and the second switch element Q2 can also be both triodes, the first switch element Q1 is an NPN triode, the collector of the first switch element Q1 is connected to V1, the emitter of the first switch element Q1 is connected to the capacitor C, and the base of the first switch element Q1 is connected to the drive circuit; the second switch element Q2 is a PNP triode, the emitter of the second switch element Q2 is connected to V2, the collector of the second switch element Q2 is connected to the capacitor C, and the base of the second switch element Q2 is connected to the drive circuit.

[0036] Furthermore, the driving circuit includes a comparator CMP, one input end (such as a non-inverting input end) of the comparator CMP is connected to the sampling circuit 10 to obtain a sampling voltage, the other input end (such as an inverting input end) of the comparator CMP is connected to a reference voltage, and the output end of the comparator CMP is coupled to the first switch element Q1 and the second switch element Q2. Thus, when the sampling voltage is greater than the reference voltage, the comparator CMP outputs a high-level signal to turn on the first switch element Q1 and turn off the second switch element Q2, and when the sampling voltage is less than or equal to the reference voltage, the comparator CMP outputs a low-level signal to turn on the second switch element Q2 and turn off the first switch element Q1.

[0037] Furthermore, the driving circuit further includes an inverter U1 and a driver U2, the input end of the inverter U1 is connected to the output end of the comparator CMP, the output end of the inverter U1 is connected to the driver U2, and the driver U2 is connected to the switch element Q of the first charging branch, so that when the sampling voltage is greater than the reference voltage, the comparator CMP outputs a high-level signal, which is output as a low level after passing through the inverter U1 to enable the driver U2, so that the driver U2 works and outputs a stable driving voltage to the first switch element Q1, thereby turning on the first switch element Q1. In one embodiment, the driver U2 can be a linear regulator.

[0038] Based on the above charging circuit, this embodiment further provides a BST chip. The BST chip includes the above charging circuit and a capacitor C. The charging branch is grounded through the capacitor C.

[0039] It should be noted that those skilled in the art can understand the working principle and other structural elements of the BST chip based on the prior art, which will not be elaborated here.

[0040] Although the utility model is disclosed as above with preferred embodiments, the above embodiments are not intended to limit the utility model. For any technician familiar with the art, without departing from the scope of the technical solution of the utility model, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the utility model, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.

Claims

1. A charging circuit, characterized in that: include: At least two charging branches, different charging branches are connected to power supply terminals of different voltage levels; A sampling circuit, wherein the sampling circuit is used to sample the power supply voltage and output the sampled voltage; A driving circuit connected to the sampling circuit determines the corresponding power supply end based on the sampling voltage, and drives the charging branch corresponding to the power supply end to be connected to one end of the capacitor.

2. The charging circuit according to claim 1, characterized in that: The charging circuit includes two charging branches, namely a first charging branch and a second charging branch; the driving circuit drives the first charging branch to be connected to the capacitor when the sampled voltage is greater than a reference voltage, and the driving circuit drives the second charging branch to be connected to the capacitor when the sampled voltage is less than or equal to the reference voltage.

3. The charging circuit according to claim 2, characterized in that: The power supply end corresponding to the first charging branch provides a first power supply voltage, and the power supply end corresponding to the second charging branch provides a second power supply voltage, and the second power supply voltage is greater than the first power supply voltage.

4. The charging circuit according to claim 2, characterized in that: The charging branch includes a switching element, which has a first voltage end, a second voltage end and a driving end. The first voltage end of the switching element is connected to the corresponding power supply end, the second voltage end of the switching element is connected to the capacitor, and the driving end of the switching element is coupled to the driving circuit.

5. The charging circuit according to claim 4, characterized in that: The switch elements of the first charging branch and the second charging branch are transistors.

6. The charging circuit according to claim 2, characterized in that: The driving circuit includes a comparator, one input end of the comparator is connected to the sampling circuit, the other input end of the comparator is connected to the reference voltage, and the output end of the comparator is coupled to the switch element of the first charging branch and the switch element of the second charging branch.

7. The charging circuit according to claim 6, characterized in that: The driving circuit further includes an inverter and a driver, wherein the input end of the inverter is connected to the output end of the comparator, the output end of the inverter is connected to the driver, and the driver is connected to the switch element of the first charging branch.

8. The charging circuit according to claim 7, characterized in that: The driver includes a linear regulator.

9. The charging circuit according to claim 1, characterized in that: The sampling circuit includes a first resistor and a second resistor, one end of the second resistor is connected to the power supply voltage, the other end of the second resistor is connected to the driving circuit, and the other end of the second resistor is also grounded through the first resistor.

10. A BST chip, characterized in that: The invention comprises a capacitor and a charging circuit as claimed in any one of claims 1 to 9, wherein a charging branch of the charging circuit is grounded through the capacitor.

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