A linear voltage-stabilized power supply with variable structure

Abstract

The present application includes a linear voltage-stabilized power supply with variable structure, and specifically relates to the field of power supply technology. The linear voltage-stabilized power supply includes a main circuit and a control circuit; in the main circuit, the output end of the reference voltage module is connected to the inverting input end of the first operational amplifier; the output end of the reference voltage module is also connected to the voltage selection node through the third switch tube; the voltage output end is connected to the non-inverting input end of the first operational amplifier through the first feedback resistor; the non-inverting input end of the first operational amplifier is also connected to the voltage selection node through the sixth switch tube; the control circuit is used to measure the voltage of the measurement node, so as to control the conduction state of each switch tube according to the components connected to the voltage selection node. The above-mentioned linear voltage-stabilized power supply can be connected to a capacitor or a feedback resistor at the voltage selection node according to the actual needs of the application circuit, thereby increasing the application range of the linear voltage-stabilized power supply.

Description

Technical Field

[0001] The invention relates to the technical field of power supplies, and in particular to a linear voltage-stabilized power supply with a variable structure. Background Art

[0002] The circuit structure of the linear voltage regulated power supply in the prior art is as follows: Figure 1 As shown, en is the first enabling voltage of the linear regulated power supply, the reference voltage module bg is used to generate a reference voltage vref, and the first operational amplifier ea adjusts the feedback voltage fb to be equal to the reference voltage vref;

[0003] In the prior art, when the linear voltage regulator is integrated into a semiconductor control chip, there are usually two design solutions: Figure 2 FIG. 1 shows a schematic diagram of the structure of a first linear voltage regulated power supply chip in the prior art. Figure 2 As shown, the first design scheme is to lead out the connection points of the ground voltage gnd, the power supply voltage vdd, the first enable voltage en, the output voltage vout and the reference voltage vref as the pins of the chip, and the first capacitor cp is a chip external capacitor set at the connection point of the reference voltage vref, which can improve the stability of the reference voltage vref, thereby improving the stability of the output voltage vout, but because the first feedback resistor rf1 and the second feedback resistor rf2 are fixed resistors inside the chip, the output voltage vout of this scheme can only be a fixed value; Figure 3 FIG. 2 shows a schematic diagram of the structure of a second linear voltage regulated power supply chip in the prior art. Figure 3 As shown, the second design scheme is that the connection points of the ground voltage gnd, the power supply voltage vdd, the first enable voltage en, the output voltage vout and the feedback voltage fb are all brought out as the pins of the chip, and the second feedback resistor rf2 is short-circuited inside the chip, and a third feedback resistor rfx is externally connected to the connection point of the feedback voltage fb. At this time, the output voltage vout can be adjusted by adjusting the resistance value of the third feedback resistor rfx. This structure allows the output voltage vout to be flexibly changed, but in order to make the chip pins simpler, this scheme usually discards the external first capacitor cp, thereby reducing the stability of the output voltage vout.

[0004] The above two solutions have their own advantages and disadvantages and can only realize their own independent functions, thus limiting the application scope of the linear regulated power supply. Summary of the invention

[0005] The embodiment of the present application provides a linear voltage-regulated power supply with a variable structure, thereby increasing the application scope of the linear voltage-regulated power supply.

[0006] On the one hand, a linear voltage-regulated power supply with a variable structure is provided, the linear voltage-regulated power supply comprising a main circuit and a control circuit;

[0007] In the main circuit, the output end of the reference voltage module is connected to the inverting input end of the first operational amplifier; the output end of the first operational amplifier is connected to the control end of the power switch tube; the output end of the reference voltage module is also connected to the voltage selection node through the third switch tube;

[0008] The power supply voltage end is connected to the voltage output end through the power switch tube; the voltage output end is connected to the non-inverting input end of the first operational amplifier through the first feedback resistor; the non-inverting input end of the first operational amplifier is connected to the current input end of the fifth switch tube; the current output end of the fifth switch tube is grounded through the fourth switch tube and the second feedback resistor respectively; the non-inverting input end of the first operational amplifier is also connected to the voltage selection node through the sixth switch tube;

[0009] In the control circuit, the power supply voltage terminal is connected to the measurement node through the first current source and the first switch tube; the measurement node is connected to the voltage selection node through the second switch tube; the control circuit is used to measure the voltage of the measurement node to control the conduction state of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube according to the components connected to the voltage selection node.

[0010] In a possible implementation manner, the voltage selection node is grounded through a first capacitor; or the voltage selection node is grounded through a third feedback resistor.

[0011] In a possible implementation manner, when the voltage selection node is grounded through the first capacitor, the third switch tube and the fifth switch tube are turned on, and the fourth switch tube and the sixth switch tube are turned off.

[0012] In a possible implementation manner, when the voltage selection node is grounded through the third feedback resistor, the third switch tube and the fifth switch tube are turned off, and the fourth switch tube and the sixth switch tube are turned on.

[0013] In a possible implementation, the reference voltage module is connected to a first enable voltage; the control terminals of the first switch tube and the second switch tube are connected to a second enable voltage;

[0014] The first enable voltage and the second enable voltage are switched from a low level to a high level at the same time, and the second enable voltage is switched back to a low level after a first time period after being switched to a high level.

[0015] In a possible implementation, in the control circuit, the measurement node is connected to the inverting input terminal of the second operational amplifier through a first follower and a second capacitor in sequence;

[0016] The non-inverting input terminal of the second operational amplifier is grounded; the inverting input terminal of the second operational amplifier is also connected to the output terminal of the second operational amplifier through a first resistor;

[0017] The output terminal of the second operational amplifier is connected to the inverting input terminal of the third operational amplifier through a second resistor; the non-inverting input terminal of the third operational amplifier is grounded; the inverting input terminal of the third operational amplifier is also connected to the output terminal of the third operational amplifier through a third resistor;

[0018] The output terminal of the third operational amplifier is connected to the first input terminal of the D flip-flop; the second input terminal of the D flip-flop is connected to the second enable voltage; the output terminal of the D flip-flop outputs a trigger voltage;

[0019] The control circuit is further used to control the conduction states of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube according to the trigger voltage and the second enable voltage.

[0020] In a possible implementation, the control circuit further includes a first AND gate and a second AND gate; the first input end of the first AND gate is connected to the inverted level of the second enable voltage; the second input end of the first AND gate is connected to the trigger voltage; the output end of the first AND gate is connected to the control end of the third switch tube and the control end of the fifth switch tube respectively;

[0021] The first input terminal of the second AND gate is connected to the inverted level of the second enable voltage; the second input terminal of the second AND gate is connected to the inverted level of the trigger voltage; the output terminal of the second AND gate is respectively connected to the control terminals of the fourth switch tube and the sixth switch tube.

[0022] In a possible implementation manner, a resistance value of the third resistor is the same as a resistance value of the second resistor.

[0023] In a possible implementation, the first follower includes a fourth operational amplifier;

[0024] The measurement node is connected to the non-inverting input terminal of the fourth operational amplifier; the inverting input terminal of the fourth operational amplifier is connected to the output terminal of the fourth operational amplifier;

[0025] The output terminal of the fourth operational amplifier is connected to the inverting input terminal of the second operational amplifier through the second capacitor.

[0026] On the other hand, an integrated circuit control chip is provided, which includes the above-mentioned linear regulated power supply; the integrated circuit control chip has a voltage selection pin; the voltage selection pin is connected to the voltage selection node; the voltage selection pin is used to connect external components.

[0027] The technical solution provided by this application may have the following beneficial effects:

[0028] A variable-structure linear voltage-regulated power supply in the present application has a ground voltage, a power supply voltage, a first enable voltage, an output voltage, and a voltage selection node all brought out as pins of a chip. When a capacitor is connected to the voltage selection node, the voltage at the voltage selection node is the reference voltage. When a feedback resistor is connected to the voltage selection node, the voltage at the voltage selection node is the feedback voltage. Therefore, according to the actual needs of the application circuit (whether a stable and fixed output voltage or an adjustable output voltage is required), a capacitor or a feedback resistor can be connected to the voltage selection node to increase the application scope of the linear voltage-regulated power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 The invention is a circuit structure of a linear voltage-stabilized power supply in the prior art.

[0031] Figure 2 The first linear voltage-stabilized power supply chip structure diagram in the prior art is shown.

[0032] Figure 3 The figure shows a schematic diagram of the structure of a second linear voltage-stabilized power supply chip in the prior art.

[0033] Figure 4 A circuit structure diagram of a linear voltage-regulated power supply with variable structure is shown.

[0034] Figure 5 The waveform diagram of the first enabling voltage and the second enabling voltage involved in the embodiment of the present application is shown.

[0035] Figure 6 The circuit structure diagram when the voltage selection node is externally connected to the third feedback resistor is shown.

[0036] Figure 7 The circuit structure diagram when the voltage selection node is externally connected to the first capacitor is shown. DETAILED DESCRIPTION

[0037] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0038] Please refer to Figure 4 ,exist Figure 1 Based on the circuit structure of the linear voltage-stabilized power supply shown in FIG. 1 , the present application embodiment shows a circuit structure diagram of a linear voltage-stabilized power supply with a variable structure. Figure 4 As shown, in the embodiment of the present application, the linear regulated power supply includes a main circuit (i.e. Figure 4 A) and the control circuit (i.e. Figure 4 (B in the figure);

[0039] In the main circuit, the output end of the reference voltage module is connected to the inverting input end of the first operational amplifier; the output end of the first operational amplifier is connected to the control end of the power switch tube; the output end of the reference voltage module is also connected to the voltage selection node through the third switch tube;

[0040] The power supply voltage end is connected to the voltage output end through the power switch tube; the voltage output end is connected to the non-inverting input end of the first operational amplifier through the first feedback resistor; the non-inverting input end of the first operational amplifier is connected to the current input end of the fifth switch tube; the current output end of the fifth switch tube is grounded through the fourth switch tube and the second feedback resistor respectively; the non-inverting input end of the first operational amplifier is also connected to the voltage selection node through the sixth switch tube;

[0041] In the control circuit, the power supply voltage terminal is connected to the measurement node through the first current source and the first switch tube; the measurement node is connected to the voltage selection node through the second switch tube; the control circuit is used to measure the voltage of the measurement node to control the conduction state of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube according to the components connected to the voltage selection node.

[0042] Optionally, in an embodiment of the present application, the voltage selection node is grounded through a first capacitor; or, the voltage selection node is grounded through a third feedback resistor.

[0043] Optionally, in an embodiment of the present application, when the voltage selection node is grounded through the first capacitor, the third switch tube and the fifth switch tube are turned on, and the fourth switch tube and the sixth switch tube are turned off.

[0044] Optionally, in an embodiment of the present application, when the voltage selection node is grounded through a third feedback resistor, the third switch tube and the fifth switch tube are turned off, and the fourth switch tube and the sixth switch tube are turned on.

[0045] Optionally, in the embodiment of the present application, the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are NMOS tubes, and the power switch tube is a PMOS tube;

[0046] Alternatively, the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are NPN transistors, and the power switch tube is a PNP transistor.

[0047] Further, the reference voltage module is connected to a first enabling voltage; the control terminals of the first switch tube and the second switch tube are connected to a second enabling voltage;

[0048] The first enable voltage and the second enable voltage are switched from a low level to a high level at the same time, and the second enable voltage is switched back to a low level after a first time period after being switched to a high level.

[0049] In the control circuit, the measurement node is connected to the inverting input terminal of the second operational amplifier through the first follower and the second capacitor in sequence;

[0050] The non-inverting input terminal of the second operational amplifier is grounded; the inverting input terminal of the second operational amplifier is also connected to the output terminal of the second operational amplifier through a first resistor;

[0051] The output terminal of the second operational amplifier is connected to the inverting input terminal of the third operational amplifier through a second resistor; the non-inverting input terminal of the third operational amplifier is grounded; the inverting input terminal of the third operational amplifier is also connected to the output terminal of the third operational amplifier through a third resistor;

[0052] The output terminal of the third operational amplifier is connected to the first input terminal of the D flip-flop; the second input terminal of the D flip-flop is connected to the second enable voltage; the output terminal of the D flip-flop outputs a trigger voltage;

[0053] The control circuit is also used to control the conduction states of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube according to the trigger voltage and the second enabling voltage.

[0054] Optionally, the control circuit further includes a first AND gate and a second AND gate; the first input end of the first AND gate is connected to the inverted level of the second enable voltage; the second input end of the first AND gate is connected to the trigger voltage; the output end of the first AND gate is respectively connected to the control end of the third switch tube and the fifth switch tube, so as to control the conduction state of the third switch tube and the fifth switch tube;

[0055] The first input end of the second AND gate is connected to the inverted level of the second enable voltage; the second input end of the second AND gate is connected to the inverted level of the trigger voltage; the output end of the second AND gate is respectively connected to the control end of the fourth switch tube and the sixth switch tube, thereby controlling the conduction state of the fourth switch tube and the sixth switch tube.

[0056] Optionally, the control circuit also includes a first inverter inv1 and a second inverter inv2; the input end of the first inverter inv1 is connected to the second enable voltage, and the output end of the first inverter inv1 outputs the inverted level of the second enable voltage; the input end of the second inverter inv2 is connected to the trigger voltage, and the output end of the second inverter inv2 outputs the inverted level of the trigger voltage.

[0057] Furthermore, the resistance value of the third resistor is the same as the resistance value of the second resistor.

[0058] like Figure 4 As shown, the first follower includes a fourth operational amplifier; the measurement node is connected to the non-inverting input terminal of the fourth operational amplifier; the inverting input terminal of the fourth operational amplifier is connected to the output terminal of the fourth operational amplifier;

[0059] The output terminal of the fourth operational amplifier is connected to the inverting input terminal of the second operational amplifier through the second capacitor.

[0060] Moreover, in an embodiment of the present application, the linear regulated power supply can be arranged in an integrated circuit control chip, wherein, except for the first capacitor cp and the third feedback resistor rfx, the remaining components of the linear regulated power supply are located inside the integrated circuit control chip, and the integrated circuit control chip has a voltage selection pin; the voltage selection pin is connected to the voltage selection node; the voltage selection pin is used to connect external components.

[0061] Among them, a first current source is arranged inside the integrated circuit control chip, and the current magnitude of the first current generated by the first current source is ix; in the integrated circuit control chip, a first enable voltage en and a second enable voltage enx are arranged, the first enable voltage en is associated with the second enable voltage enx, and is in a normally low state, when the linear voltage regulator is started, the first enable voltage en is switched from a low level to a high level, when the first enable voltage en is switched from a low level to a high level, the second enable voltage enx is switched to a high level at the same time, and the second enable voltage enx is switched back to a low level after maintaining a high level for a period of time, and the waveforms of the first enable voltage en and the second enable voltage enx are as shown in Figure 5 shown.

[0062] At this time, if Figure 4The working principle of the control circuit in the linear regulated power supply shown is as follows:

[0063] First, when Figure 4 When the voltage selection node of the control circuit in the linear voltage regulated power supply shown in FIG. 1 is connected to the third feedback resistor rfx, the circuit structure diagram of the control circuit is as shown in FIG. Figure 6 shown.

[0064] When the linear regulated power supply starts working, the first enable voltage en is switched from a low level to a high level, and the second enable voltage enx is temporarily at a high level. Since the control ends of the first switch tube Mc1 and the second switch tube Mc2 are respectively connected to the second enable voltage enx, and in the embodiment of the present application, the first switch tube Mc1 and the second switch tube Mc2 are NMOS tubes or NPN transistors, the first switch tube Mc1 and the second switch tube Mc2 are turned on at this time, and the first current flows to the third feedback resistor rfx through the first switch tube Mc1 and the second switch tube Mc2.

[0065] At this time, the voltage vx at the measurement node is equal to ix×rfx, so the voltage at the in-phase input terminal of the fourth operational amplifier ea4 is also equal to ix×rfx, that is, at this time, the voltage at the in-phase input terminal of the fourth operational amplifier ea4 is a fixed value, and because the fourth operational amplifier forms a follower structure, the output voltage va of the fourth operational amplifier ea4 is also a fixed value; at this time, Figure 6 It can be seen from the circuit structure that the non-inverting input terminals of the second operational amplifier ea2 and the third operational amplifier ea3 are both grounded. Therefore, according to the virtual short characteristic of the operational amplifier, the voltage vb of the inverting input terminal of the second operational amplifier ea2 and the voltage vd of the inverting input terminal of the third operational amplifier ea3 are both 0V. According to the virtual open characteristic of the operational amplifier, the current ia flowing through the second capacitor ca flows entirely through the first resistor ra, and the current ib flowing through the second resistor rb flows entirely through the third resistor rc. At the same time, since the output voltage va of the fourth operational amplifier ea4 is a fixed value, and a second capacitor ca is provided between the output terminal of the fourth operational amplifier ea4 and the inverting input terminal of the second operational amplifier ea2, at this time, the second capacitor ca can be regarded as an open circuit, and the voltage of the inverting input terminal of the second operational amplifier ea2 is always 0V. Therefore, ia=ib=0A, and the voltage vd of the inverting input terminal of the third operational amplifier ea3 is also always 0V, so that the output voltage ve of the third operational amplifier ea3 is 0V, that is, the third operational amplifier ea3 outputs a low level.

[0066] Therefore, since the first input terminal of the D flip-flop is connected to the output voltage of the third operational amplifier ea3, and the second input terminal of the D flip-flop is connected to the second enable voltage enx; and when the linear regulated power supply starts to work, the output voltage ve of the third operational amplifier ea3 is at a low level, and the second enable voltage enx is at a high level, therefore, the trigger voltage vk output by the D flip-flop is at a low level;

[0067] Afterwards, the second enable voltage enx switches back to a low level after a period of time. At this time, the state of the trigger voltage vk of the D flip-flop is locked and does not change with the output voltage ve of the third operational amplifier ea3. Therefore, when the linear regulated power supply starts to work, the trigger voltage vk of the D flip-flop is always at a low level.

[0068] At this time, Figure 4 In the circuit shown, the second enable voltage enx passes through the first inverter inv1 to obtain the second enable voltage inversion level enxb, and the second enable voltage enx is at a high level for a period of time and then switches to a low level. Therefore, the second enable voltage inversion level enxb is at a low level for a period of time and then switches to a high level.

[0069] Since the trigger voltage vk of the D flip-flop passes through the second inverter inv2 to obtain the inverted level vkb of the trigger voltage of the D flip-flop, that is, the inverted level vkb of the trigger voltage of the D flip-flop is always at a high level, it can be obtained that when the voltage selection node in the control circuit is externally connected to the third feedback resistor rfx, the output voltage vm of the first AND gate is always at a low level, and the output voltage vq of the second AND gate is at a low level for a period of time. After the second enable voltage enx is switched to a low level, the output voltage vq of the second AND gate finally maintains a high level state.

[0070] Furthermore, if Figure 4 When the voltage selection node of the control circuit in the linear voltage regulated power supply shown in FIG. 1 is connected to a first capacitor cp, the circuit structure of the control circuit is as shown in FIG. Figure 7 shown.

[0071] When the linear regulated power supply starts working, the first enable voltage en is switched from a low level to a high level, and the second enable voltage enx is temporarily a high level. Since the control ends of the first switch tube Mc1 and the second switch tube Mc2 are respectively connected to the second enable voltage enx, and in the embodiment of the present application, the first switch tube Mc1 and the second switch tube Mc2 are NMOS tubes or NPN transistors, the first switch tube Mc1 and the second switch tube Mc2 are turned on at this time. Therefore, the first current flowing through the first switch tube Mc1 and the second switch tube Mc2 flows to the first capacitor cp to charge the first capacitor cp. Therefore, the voltage vx at the measurement node gradually increases. It can be seen from the capacitor charging formula that vx=(ix×t) / cp, and since the fourth operational amplifier constitutes a follower structure, the output voltage va of the fourth operational amplifier ea4 is equal to the voltage vx at the measurement node.

[0072] At this time, by Figure 7 It can be seen from the circuit structure that the in-phase input terminals of the second operational amplifier ea2 and the third operational amplifier ea3 are both grounded. Therefore, according to the virtual short characteristic of the operational amplifier, the voltage vb of the inverting input terminal of the second operational amplifier ea2 and the voltage vd of the inverting input terminal of the third operational amplifier ea3 are both 0V. According to the virtual open characteristic of the operational amplifier, the current ia flowing through the second capacitor ca all flows through the first resistor ra, and the current ib flowing through the second resistor rb all flows through the third resistor rc.

[0073] At the same time, since the output voltage of the fourth operational amplifier ea4 , that is, the output voltage va is a gradually increasing voltage, so at this time, the current ia is generated in the second capacitor ca, and since the voltage vb of the inverting input terminal of the second operational amplifier ea2 is 0V; thus, it can be obtained , , and since the voltage vd at the inverting input terminal of the third operational amplifier ea3 is also 0V, therefore, , thus we can get At this time, when the resistance value of the third resistor rc is designed to be equal to the resistance value of the second resistor rb, we can get , and because ,therefore, , thus we can get Therefore, the resistance value of the first resistor ra, the capacitance value of the second capacitor ca and the current size ix of the first current can be adjusted to ensure that the output voltage ve of the third operational amplifier ea3 is a higher value, that is, at this time, the third operational amplifier ea3 outputs a high level;

[0074] Therefore, when the linear voltage-regulated power supply starts to work, the first input terminal and the second input terminal of the D flip-flop are respectively connected to the high-level second enable voltage enx and the high-level output voltage ve of the third operational amplifier ea3. At this time, the trigger voltage vk of the D flip-flop switches to a high level following the high-level output voltage ve of the third operational amplifier ea3. Afterwards, when the second enable voltage enx switches back to a low level from a high level, the state of the trigger voltage vk of the D flip-flop is locked and does not change with the output voltage ve of the third operational amplifier ea3. Therefore, it can be obtained that when the linear voltage-regulated power supply starts to work, the trigger voltage vk of the D flip-flop is always at a high level.

[0075] The second enable voltage enx passes through the first inverter inv1 to obtain the inverted level enxb of the second enable voltage, and the second enable voltage enx is at a high level for a period of time and then switches to a low level. Therefore, the inverted level enxb of the second enable voltage is at a low level for a period of time and then switches to a high level. In addition, since the trigger voltage vk of the D flip-flop passes through the second inverter inv2 to obtain the inverted level vkb of the trigger voltage of the D flip-flop, that is, the inverted level vkb of the trigger voltage of the D flip-flop is always at a low level, it can be obtained that when Figure 7 When a first capacitor cp is externally connected to the connection of the voltage selection node of the control circuit shown, the output voltage vq of the second AND gate is always at a low level, and the output voltage vm of the first AND gate is at a low level for a period of time. After the second enable voltage enx is switched to a low level, the output voltage vm of the first AND gate finally maintains a high level state.

[0076] From the above analysis, it can be seen that when a resistor or capacitor is externally connected to the connection point of the voltage selection node, the control circuit outputs different control voltages; afterwards, if the state of the control voltage is to be changed, the enable voltage en can be switched to a low level and then switched back to a high level. At this time, the second enable voltage enx temporarily becomes a high level, thereby re-reading the state of the control voltage;

[0077] At this time, return to Figure 4 A variable structure linear voltage regulated power supply, its working principle is:

[0078] When the linear voltage-stabilized power supply starts to work, the first enable voltage en is switched from a low level to a high level, the second enable voltage enx is temporarily a high level, and the inverted level enxb of the second enable voltage is temporarily a low level. Therefore, at this time, the output terminal voltage vm of the first AND gate and the output terminal voltage vq of the second AND gate are both low levels, the first switch tube Mc1 and the second switch tube Mc2 are both turned on, and the third switch tube Mc3 to the eighth switch tube Mc8 are all turned off. At this time, the control circuit determines whether the connection of the voltage selection node is externally connected to a resistor or a capacitor. After a short period of time, the second enable voltage enx is switched to a low level, and the first switch tube Mc1 and the second switch tube Mc2 are both turned off. Therefore, the first current in the control circuit does not affect the normal operation of the linear voltage-stabilized power supply;

[0079] At this time, when Figure 4 When the voltage selection node of the control circuit in the circuit is externally connected to the first capacitor cp, the output terminal voltage vq of the second AND gate is low level, and the first switch tube Mc1 and the second switch tube Mc2 are both turned off, ensuring that the first current in the control circuit does not affect the normal operation of the linear voltage-regulated power supply, the output terminal voltage vm of the first AND gate is switched to a high level, the third switch tube Mc3 and the fifth switch tube Mc5 are turned on, and the fourth switch tube Mc4 and the sixth switch tube Mc6 are turned off. At this time, in the linear voltage-regulated power supply circuit, the first capacitor cp is a chip external capacitor arranged at the connection of the reference voltage vref, which can improve the stability of the reference voltage vref, thereby improving the stability of the output voltage vout;

[0080] When Figure 4 When the voltage selection node of the control circuit is externally connected to the third feedback resistor rfx, the output terminal voltage vm of the first AND gate is low level, and the first switch tube Mc1 and the second switch tube Mc2 are both turned off to ensure that the first current in the control circuit does not affect the normal operation of the linear voltage regulated power supply, the output terminal voltage vq of the second AND gate is switched to a high level, the third switch tube Mc3 and the fifth switch tube Mc5 are turned off, and the fourth switch tube Mc4 and the sixth switch tube Mc6 are turned on. At this time, the output voltage vout can be adjusted by adjusting the resistance value of the third feedback resistor rfx;

[0081] From the above analysis, it can be seen that the ground voltage gnd, power supply voltage vdd, first enable voltage en, output voltage vout and voltage selection node of the linear regulated power supply in this application can be brought out as pins of the chip. When the voltage selection node is externally connected to the first capacitor cp, the voltage vy at the voltage selection node is the reference voltage vref; when the voltage selection node is externally connected to the third feedback resistor rfx, the voltage vy at the voltage selection node is the feedback voltage fb.

[0082] Therefore, the linear regulated power supply in the present application is a linear regulated power supply with a variable structure. According to the actual needs of the application circuit (whether a stable and fixed output voltage or an adjustable output voltage is required), a first capacitor cp or a third feedback resistor rfx can be externally connected to the voltage selection node, thereby increasing the application range of the linear regulated power supply.

[0083] To sum up, in the present application, a linear voltage-regulated power supply with a variable structure has its ground voltage, power supply voltage, first enable voltage, output voltage and voltage selection node all brought out as pins of the chip. When a capacitor is connected to the voltage selection node, the voltage at the voltage selection node is the reference voltage. When a feedback resistor is connected to the voltage selection node, the voltage at the voltage selection node is the feedback voltage. Therefore, according to the actual needs of the application circuit (whether a stable and fixed output voltage or an adjustable output voltage is required), a capacitor or a feedback resistor can be connected to the voltage selection node to increase the application scope of the linear voltage-regulated power supply.

[0084] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0085] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A linear voltage-regulated power supply with variable structure, It is characterized in that The linear voltage-regulated power supply comprises a main circuit and a control circuit; In the main circuit, the output end of the reference voltage module is connected to the inverting input end of the first operational amplifier; the output end of the first operational amplifier is connected to the control end of the power switch tube; the output end of the reference voltage module is also connected to the voltage selection node through the third switch tube; The power supply voltage end is connected to the voltage output end through the power switch tube; the voltage output end is connected to the non-inverting input end of the first operational amplifier through the first feedback resistor; the non-inverting input end of the first operational amplifier is connected to the current input end of the fifth switch tube; the current output end of the fifth switch tube is grounded through the fourth switch tube and the second feedback resistor respectively; the non-inverting input end of the first operational amplifier is also connected to the voltage selection node through the sixth switch tube; In the control circuit, the power supply voltage terminal is connected to the measurement node through the first current source and the first switch tube; the measurement node is connected to the voltage selection node through the second switch tube; the control circuit is used to measure the voltage of the measurement node to control the conduction state of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube according to the components connected to the voltage selection node; the voltage selection node is grounded through the first capacitor; or, the voltage selection node is grounded through the third feedback resistor.

2. The linear regulated power supply according to claim 1, It is characterized in that When the voltage selection node is grounded through the first capacitor, the third switch tube and the fifth switch tube are turned on, and the fourth switch tube and the sixth switch tube are turned off.

3. The linear regulated power supply according to claim 1, It is characterized in that When the voltage selection node is grounded through the third feedback resistor, the third switch tube and the fifth switch tube are turned off, and the fourth switch tube and the sixth switch tube are turned on.

4. The linear regulated power supply according to claim 3, It is characterized in that The reference voltage module is connected to a first enabling voltage; the control terminals of the first switch tube and the second switch tube are connected to a second enabling voltage; The first enable voltage and the second enable voltage are switched from a low level to a high level at the same time, and the second enable voltage is switched back to a low level after a first time period after being switched to a high level.

5. The linear regulated power supply according to claim 4, It is characterized in that In the control circuit, the measurement node is connected to the inverting input terminal of the second operational amplifier through the first follower and the second capacitor in sequence; The non-inverting input terminal of the second operational amplifier is grounded; the inverting input terminal of the second operational amplifier is also connected to the output terminal of the second operational amplifier through a first resistor; The output terminal of the second operational amplifier is connected to the inverting input terminal of the third operational amplifier through a second resistor; the non-inverting input terminal of the third operational amplifier is grounded; the inverting input terminal of the third operational amplifier is also connected to the output terminal of the third operational amplifier through a third resistor; The output terminal of the third operational amplifier is connected to the first input terminal of the D flip-flop; the second input terminal of the D flip-flop is connected to the second enable voltage; the output terminal of the D flip-flop outputs a trigger voltage; The control circuit is further used to control the conduction states of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube according to the trigger voltage and the second enable voltage.

6. The linear regulated power supply according to claim 5, It is characterized in that The control circuit further includes a first AND gate and a second AND gate; the first input end of the first AND gate is connected to the inverted level of the second enable voltage; the second input end of the first AND gate is connected to the trigger voltage; the output end of the first AND gate is connected to the control end of the third switch tube and the control end of the fifth switch tube respectively; The first input terminal of the second AND gate is connected to the inverted level of the second enable voltage; the second input terminal of the second AND gate is connected to the inverted level of the trigger voltage; the output terminal of the second AND gate is respectively connected to the control terminals of the fourth switch tube and the sixth switch tube.

7. The linear regulated power supply according to claim 6, It is characterized in that The resistance value of the third resistor is the same as the resistance value of the second resistor.

8. The linear regulated power supply according to claim 6, It is characterized in that The first follower includes a fourth operational amplifier; The measurement node is connected to the non-inverting input terminal of the fourth operational amplifier; the inverting input terminal of the fourth operational amplifier is connected to the output terminal of the fourth operational amplifier; The output terminal of the fourth operational amplifier is connected to the inverting input terminal of the second operational amplifier through the second capacitor.

9. An integrated circuit control chip, It is characterized in that The integrated circuit control chip includes a linear voltage-regulated power supply as described in any one of claims 1 to 8; the integrated circuit control chip has a voltage selection pin; the voltage selection pin is connected to the voltage selection node; the voltage selection pin is used to connect external components.

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