Regulation circuit including multiple low voltage drop output regulators and operation method thereof

Abstract

A regulation circuit may be provided, comprising: a first direct current-to-direct current (DC-DC) converter configured to apply a first power supply voltage to a first node in a first mode and to apply the first power supply voltage to a second node in a second mode; a first low dropout output (LDO) regulator connected to the first node, the first LDO regulator configured to provide an output voltage to an output node by regulating the first power supply voltage at the first node; and a second LDO regulator connected to the first node, the second LDO regulator configured to provide an auxiliary current to the first node in a second mode.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2019-0037306 filed on March 29, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The inventive concept relates to a regulation circuit for supplying a voltage by using a plurality of low dropout output (LDO) regulators and a converter, and / or a method of operating the regulation circuit. Background Art

[0004] Typically, the regulation circuit converts the power input from the outside into the direct current (DC) power desired by the system by using a power switch. The power regulator included in the regulation circuit may be, for example, a DC-DC converter for increasing or decreasing the voltage of the input DC power. An LDO regulator, which is a linear regulator operating at a low input-output potential difference, is referred to as a low-damage linear regulator or a low-saturation linear regulator. Therefore, in order to output the same voltage, the LDO regulator may expect a low input voltage.

[0005] In particular, the LDO regulator may include a load capacitor. Depending on the size of the load capacitor, the magnitude of the ripple voltage and the time it takes for the output voltage to stabilize may be a trade-off relationship. Therefore, a structure of a regulation circuit capable of reducing the ripple voltage without increasing the size of the load capacitor included in the LDO regulator is desired. Summary of the invention

[0006] The inventive concept provides a regulating circuit and / or an operating method thereof for providing a stable output voltage by reducing a ripple voltage using a plurality of low dropout output (LDO) regulators and converters.

[0007] The inventive concept also provides a regulating circuit for providing a stable voltage to a plurality of nodes by using a plurality of DC-DC converters and / or an operating method thereof.

[0008] According to an example embodiment of the present inventive concept, a regulation circuit may include: a first direct current-to-direct current (DC-DC) converter configured to apply a first power supply voltage to a first node in a first mode and to apply the first power supply voltage to a second node in a second mode; a first low dropout output (LDO) regulator connected to the first node, the first LDO regulator configured to provide an output voltage to an output node by regulating the first power supply voltage of the first node; and a second LDO regulator connected to the first node, the second LDO regulator configured to provide an auxiliary current to the first node in the second mode.

[0009] According to an example embodiment of the present inventive concept, a regulation circuit may include a first direct current-to-direct current (DC-DC) converter configured to provide a first power supply voltage; a switch circuit configured to connect an output terminal of the first DC-DC converter to one of a first node or a second node based on a mode setting signal; a first LDO regulator configured to provide an output voltage to an output node by regulating a voltage of the first node; and a second LDO regulator configured to increase a voltage level of the first node to a level of the first power supply voltage by supplying an output current to the first node when the first DC-DC converter is connected to the second node.

[0010] According to an example embodiment conceived by the present invention, an operating method of a regulation circuit for supplying an output voltage by regulating a voltage of a first node may include: switching an output terminal of a first direct current-to-direct current (DC-DC) converter from a first node to a second node; applying an auxiliary current to the first node by a first low dropout output (LDO) regulator; and supplying the output voltage by regulating the voltage of the first node by a second LDO regulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The embodiments of the present invention will be more clearly understood from the following detailed description in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a block diagram illustrating an electronic device according to an exemplary embodiment of the inventive concept;

[0013] Figure 2 is a circuit diagram illustrating a regulating circuit according to an example embodiment of the inventive concept;

[0014] Figure 3 is a timing diagram illustrating the operation of a regulating circuit according to an example embodiment of the inventive concept;

[0015] Figure 4 is a circuit diagram illustrating a regulating circuit according to an example embodiment of the inventive concept;

[0016] Figure 5 is a table illustrating a switching operation of a regulating circuit according to an example embodiment of the inventive concept;

[0017] FIG. 6A to FIG. 6D It shows Figure 4 A circuit diagram of the operation of the regulating circuit;

[0018] Figure 7 is a view showing a regulating circuit according to an example embodiment of the inventive concept;

[0019] Figure 8is a timing diagram illustrating the operation of a regulating circuit according to an example embodiment of the inventive concept;

[0020] Fig. 9 is a block diagram illustrating a regulating circuit according to an example embodiment of the inventive concept;

[0021] Fig.10 is a flowchart illustrating a method of operating a regulating circuit according to an example embodiment of the inventive concept;

[0022] Fig.11 is a flowchart illustrating a method of operating a regulating circuit according to an example embodiment of the inventive concept;

[0023] Fig.12 is a flowchart illustrating a method of operating a current assist circuit according to an example embodiment of the inventive concept; and

[0024] Fig.13 is a block diagram illustrating an electronic device according to an example embodiment of the inventive concept. DETAILED DESCRIPTION

[0025] Figure 1 is a block diagram illustrating an electronic device 10 according to an exemplary embodiment of the inventive concept.

[0026] refer to Figure 1 , the electronic device 10 may include a regulating circuit 100, a power supply 300, and a control logic 400. The power supply 300 may generate a plurality of power supply voltages based on an external power voltage, and provide an input voltage Vin among the plurality of power voltages to the regulating circuit 100.

[0027] The regulation circuit 100 may include a first low dropout (LDO) regulator LDO1, a second LDO regulator LDO2, and a direct current-to-direct current (DC-DC) converter DDC, and may generate an output voltage Vout by regulating an input voltage Vin received from a power supply 300. In an example embodiment, the regulation circuit 100 may receive a mode setting signal Sig_MS from the control logic 400, and provide various voltages to a plurality of nodes based on the mode setting signal Sig_MS. The control logic 400 may generate the mode setting signal Sig_MS in response to a power supply voltage request signal for at least one of the plurality of nodes.

[0028] The DC-DC converter DDC may receive a DC input voltage Vin, increase or decrease the DC input voltage Vin, and output a DC voltage. In an example, the DC-DC converter DDC may be implemented by a step-down converter or a buck converter. In an example embodiment, the DC-DC converter DDC may provide voltages to a plurality of nodes based on a mode setting signal Sig_MS. In an example embodiment, the DC-DC converter DDC may reduce the input voltage Vin based on a mode setting signal Sig_MS received from the control logic 400, and provide the reduced input voltage Vin to a first LDO regulator LDO1 or another device through a first node or a second node.

[0029] The first LDO regulator LDO1 may provide an output voltage Vout having a specific value to another device or a functional block of the electronic device 10 by regulating the reduced voltage received from the DC-DC converter DDC.

[0030] The second regulator LDO2 may be connected to the first LDO regulator LDO1 through the first node. According to example embodiments, the DC-DC converter DDC may stop supplying voltage to the first LDO regulator LDO1. In example embodiments, as described above, the DC-DC converter DDC may supply voltage to the second node instead of the first node connected to the first LDO regulator LDO1 based on the mode setting signal Sig_MS.

[0031] Each of the first LDO regulator LDO1 and the second LDO regulator LDO2 may include a load capacitor, an amplifier for amplifying a difference between a reference voltage and a feedback voltage, and a power transistor for providing a final output voltage based on an output voltage of the amplifier. In an example embodiment, the first LDO regulator LDO1 and the second LDO regulator LDO2 may include different kinds of power transistors. In an example embodiment, the first LDO regulator LDO1 may include an n-channel metal oxide semiconductor (NMOS) transistor as a power transistor, and the second LDO regulator LDO2 may include a p-channel metal oxide semiconductor (PMOS) transistor as a power transistor.

[0032] According to some example embodiments of the inventive concept, the second LDO regulator LDO2 may output an auxiliary current to the first node during a period in which the DC-DC converter DDC does not provide a voltage, and therefore, the voltage level of the first node may not decrease. Therefore, even during a period in which the DC-DC converter DDC does not provide a voltage, a stable voltage may be input to the first LDO regulator LDO1.

[0033] Figure 21 is a circuit diagram showing a regulation circuit 100 according to an exemplary embodiment of the inventive concept. Figure 1 Description given.

[0034] refer to Figure 2 , the regulation circuit 100 may include a DC-DC converter 110, a switch circuit 120, a first LDO regulator 130 and a second LDO regulator 140. The DC-DC converter 110 may be connected to a first node N1 and a second node N2 through the switch circuit 120. The switch circuit 120 may include a first switch SW1 and a second switch SW2. The first switch SW1 may electrically connect or disconnect the DC-DC converter 110 to or from the first node N1 based on the first mode signal MS1. The second switch SW2 may electrically connect or disconnect the DC-DC converter 110 to or from the second node N2 based on the second mode signal MS2. In an example embodiment, the control logic 400( Figure 1 ) receives the first mode signal MS1 and the second mode signal MS2 as the mode setting signal Sig_MS.

[0035] The first switch SW1 and the second switch SW2 may be configured by various switch devices capable of controlling electrical connection based on an external signal. In an example, the first switch SW1 and the second switch SW2 may be configured by transistors. In an example embodiment, the first switch SW1 and the second switch SW2 may operate complementarily.

[0036] In an example, in a first mode, the first switch SW1 may be short-circuited (in other words, turned on), the second switch SW2 may be open-circuited (in other words, turned off), and thus, the DC-DC converter 110 may be connected to the first node N1. Therefore, the power supply voltage provided from the DC-DC converter 110 may be provided to the first LDO regulator 130 through the first node N1. In addition, in a second mode, the first switch SW1 may be open-circuited and the second switch SW2 may be short-circuited, and thus, the DC-DC converter 110 may be connected to the second node N2. Therefore, the power supply voltage provided from the DC-DC converter 110 may be provided to an external device through the second node N2.

[0037] The first LDO regulator 130 may generate an output voltage by regulating the voltage of the first node N1 and provide the generated output voltage to an external device through the output node Nout. In the first mode, the first LDO regulator 130 may generate an output voltage by receiving a power supply voltage provided from the DC-DC converter 110 via the first node N1 and regulating the received power supply voltage.

[0038] In the second mode, the second LDO regulator 140 can output an auxiliary current I_aux to the first node N1. Therefore, even when the first switch SW1 is open, the phenomenon that no voltage is supplied to the first node N1 can be avoided. The first LDO regulator 130 can generate an output voltage by receiving a voltage from the second LDO regulator 140 via the first node N1 and regulating the received voltage.

[0039] According to some example embodiments of the inventive concept, similar to the above-described second mode, even when the DC-DC converter 110 does not provide a power supply voltage to the first LDO regulator 130 but provides a power supply voltage to another node according to an additional request, the first LDO regulator 130 may receive a voltage from the second LDO regulator 140. Therefore, a stable output voltage may be generated.

[0040] exist Figure 2 , an example of controlling the connection between the DC-DC converter 110 and the first node N1 and the second node N2 by two switches SW1 and SW2 is shown. However, example embodiments of the inventive concept are not limited thereto. According to some example embodiments, the connection between the DC-DC converter 110 and the first node N1 and the second node N2 may be controlled by more than two switching devices.

[0041] Figure 3 is a timing diagram illustrating the operation of a regulating circuit according to an example embodiment of the inventive concept. Figure 3 The X-axis shows time and Figure 3 The Y-axis shows the potential of the node or the logic level of the signal.

[0042] refer to Figure 2 and Figure 3 , in the first mode Md1, the first mode signal MS1 may maintain a logic high, and the second mode signal MS2 may maintain a logic low. Based on the first mode signal MS1 and the second mode signal MS2, the first switch SW1 may be short-circuited (turned on), and the second switch SW2 may be open (disconnected). Therefore, the DC-DC converter 110 may be connected to the first node N1, and may provide a power supply voltage with a stable ripple to the first node N1, and thus the voltage of the output node Nout may also have a stable ripple.

[0043] When the mode is changed from the first mode Md1 to the second mode Md2, the first mode signal MS1 may be changed from logic high to logic low, and the second mode signal MS2 may be changed from logic low to logic high. Based on the first mode signal MS1 and the second mode signal MS2, the first switch SW1 may be open (disconnected), and the second switch SW2 may be short-circuited (connected). Therefore, the DC-DC converter 110 is connected to the second node N2, and the power supply voltage may be provided to the second node N2.

[0044] Since the power supply voltage is not supplied to the first node N1, the voltage of the first node N1 and the voltage of the output node Nout generated by adjusting the voltage of the first node N1 may be temporarily reduced in level. However, the voltage level of the first node N1 may be restored to be the same or substantially similar to the voltage level in the first mode Md1 by outputting the auxiliary current I_aux by the second LDO regulator 140. In addition, the voltage level of the output node Nout generated by adjusting the voltage of the first node N1 may be restored to be the same or substantially similar to the level in the first mode Md1.

[0045] According to some example embodiments of the inventive concept, even in the second mode Md2 where the power voltage of the DC-DC converter 110 is not provided to the first node N1, the voltage of the output node Nout may have a stable ripple by providing the auxiliary current I_aux by the second LDO regulator 140.

[0046] Figure 4 2 is a circuit diagram showing a regulation circuit 200 according to an exemplary embodiment of the inventive concept. Figure 2 Description given.

[0047] refer to Figure 4 , the regulation circuit 200 may include a first DC-DC converter 211, a second DC-DC converter 212, a switch circuit 220, a first LDO regulator 230 and a second LDO regulator 240. Because the operations of the first DC-DC converter 211, the first LDO regulator 230 and the second LDO regulator 240 are similar to Figure 2 The DC-DC converter 110, the first LDO regulator 130 and the second LDO regulator 140 are identical or substantially similar, so the previous reference is omitted. Figure 2 Description given.

[0048] The switch circuit 220 may include first to fifth switches SW1 to SW5. Figure 2The first switch SW1 and the second switch SW2 are described in detail, so their description is omitted. The third switch SW3 can electrically connect or disconnect the first DC-DC converter 211 with the third node N3 based on the third mode signal MS3. Similarly, the fourth switch SW4 can electrically connect or disconnect the second DC-DC converter 212 with the second node N2 based on the fourth mode signal MS4, and the fifth switch SW5 can electrically connect or disconnect the second DC-DC converter 212 with the third node N3 based on the fifth mode signal MS5.

[0049] The first to fifth switches SW1 to SW5 may be configured by various switch devices capable of controlling electrical connection based on external signals (e.g., the first to fifth mode signals MS1 to MS5). In an example, the first to fifth switches SW1 to SW5 may be configured by transistors. In an example embodiment, the control logic 400 ( Figure 1 ) receives the first mode signal MS1 to the fifth mode signal MS5 as the mode setting signal Sig_MS.

[0050] According to the operation of the switch circuit 220, the first DC-DC converter 211 may be connected to one of the first node N1, the second node N2, or the third node N3, and may supply the first power supply voltage to one of the first node N1, the second node N2, or the third node N3. The second DC-DC converter 212 may be connected to at least one of the second node N2 or the third node N3, and may supply the second power supply voltage to at least one of the second node N2 or the third node N3. In example embodiments, the second power supply voltage provided by the second DC-DC converter 212 may have a level higher or lower than that of the first power supply voltage provided by the first DC-DC converter 211.

[0051] According to an example embodiment of the inventive concept, when the second DC-DC converter 212 provides voltages to a plurality of nodes (e.g., the second node N2 and the third node N3), the first DC-DC converter 211 may not be connected to the first node N1 and may be connected to another node (e.g., the second node N2 or the third node N3). That is, before the second DC-DC converter 212 applies the second power supply voltage to the second node N2 and the third node N3, the first DC-DC converter 211 may first increase and decrease the voltage level of the second node N2 or the third node N3. The voltage level of the second node N2 or the third node N3 may increase and decrease in a short time.

[0052] In addition, according to an embodiment of the present inventive concept, even when the first DC-DC converter 211 is used to increase and decrease the voltage level of another node (e.g., the second node N2 or the third node N3) instead of increasing or decreasing the voltage level of the first node N1, the second LDO regulator 240 can maintain the voltage level of the first node N1, and thus the first LDO regulator 230 can stably provide an output voltage to the output node Nout.

[0053] Figure 4 The regulation circuit 200 is shown to transmit power to the outside (for example, the electronic device 10 ( Figure 1 ) provides an example of a voltage to other devices in ). However, example embodiments of the inventive concept are not limited thereto. In some example embodiments, the regulating circuit 200 may provide a voltage to the outside through more or less than three nodes.

[0054] The control logic 400 may provide the second mode signal MS2 and the third mode signal MS3 based on (or alternatively, in response to) a power supply voltage request signal of at least one of the second node or the third node. In other words, the regulation circuit may receive the second mode signal MS2 and the third mode signal MS3 that have been generated based on (or alternatively, in response to) a power supply voltage request signal of at least one of the second node or the third node.

[0055] Figure 5 is a table illustrating a switching operation of a regulating circuit according to an example embodiment of the inventive concept. FIG. 6A to FIG. 6D It shows Figure 4 A circuit diagram of the operation of the regulation circuit 200.

[0056] refer to Figure 4 and Figure 5 , the regulation circuit 200 can operate in one of the first mode Md1, the second mode Md2, the third mode Md3, and the fourth mode Md4. In the first mode Md1, the first DC-DC converter 211 can apply the first power supply voltage to the first node N1, and the second DC-DC converter 212 can apply the second power supply voltage to the second node N2.

[0057] In the second mode Md2, according to the control logic 400 ( Figure 1 ), the second DC-DC converter 212 may apply the second power supply voltage to the second node N2, and the first DC-DC converter 211 may apply the first power supply voltage to the third node N3.

[0058] In the third mode Md3, after the third node N3 has the first power voltage in the second mode Md2, the second DC-DC converter 212 may apply the second power voltage to the third node N3 and the first DC-DC converter 211 may apply the first power voltage to the first node N1 again.

[0059] In the fourth mode Md4, according to the control logic 400 ( Figure 1 ), the second DC-DC converter 212 may apply the second power supply voltage to the third node N3, and the first DC-DC converter 211 may apply the first power supply voltage to the second node N2.

[0060] After the fourth mode Md4 , the operation in the first mode Md1 may be performed again, and the operations in the first to fourth modes Md1 to Md4 may be repeated.

[0061] Fig. 6A FIG. 2 shows an example in which the regulation circuit 200 operates in the first mode Md1. Figure 5 and Fig. 6A , in the first mode Md1 , the first switch SW1 and the fourth switch SW4 are short-circuited (turned on), and the second switch SW2 , the third switch SW3 , and the fifth switch SW5 may be open-circuited (turned off).

[0062] When the first switch SW1 is short-circuited, the first DC-DC converter 211 may provide the first power supply voltage Vs1 to the first node N1. The first LDO regulator 240 may provide the output voltage Vout to the output node Nout by regulating the first power supply voltage Vs1 of the first node N1. When the fourth switch SW4 is short-circuited, the second DC-DC converter 212 may supply the second power supply voltage Vs2 to the second node N2. The third node N3 may maintain a floating state.

[0063] Figure 6B FIG. 2 shows an example in which the regulation circuit 200 operates in the second mode Md2. Figure 5 and Figure 6B , in the second mode Md2 , the third switch SW3 and the fourth switch SW4 are short-circuited (turned on), and the first switch SW1 , the second switch SW2 , and the fifth switch SW5 may be open-circuited (turned off).

[0064] When the fourth switch SW4 is short-circuited, the second DC-DC converter 212 may supply the second power supply voltage Vs2 to the second node N2. When the third switch SW3 is short-circuited, the first DC-DC converter 211 may supply the first power supply voltage Vs1 to the third node N3. The connection between the first node N1 and the first DC-DC converter 211 may be cut off. The voltage level of the first power supply voltage Vs1 may be restored by the auxiliary current I_aux generated by the second LDO regulator 230. Therefore, although the connection between the first node N1 and the first DC-DC converter 211 is cut off, the first LDO regulator 240 may provide the output voltage Vout to the output node Nout by regulating the first power supply voltage Vs1 of the first node N1.

[0065] Figure 6C FIG. 2 shows an example in which the regulation circuit 200 operates in the third mode Md3. Figure 5 and Figure 6C , in the third mode Md3 , the first switch SW1 and the fifth switch SW5 are short-circuited (turned on), and the second switch SW2 , the third switch SW3 , and the fourth switch SW4 may be open-circuited (turned off).

[0066] When the first switch SW1 is short-circuited, the first DC-DC converter 211 can provide the first power supply voltage Vs1 to the first node N1. The first LDO regulator 240 can stably provide the output voltage Vout to the output node Nout by regulating the first power supply voltage Vs1 of the first node N1. When the fifth switch SW5 is short-circuited, the second DC-DC converter 212 can supply the second power supply voltage Vs2 to the third node N3.

[0067] Fig.6D FIG. 2 shows an example in which the regulation circuit 200 operates in the fourth mode Md4. Figure 5 and Fig.6D In the fourth mode Md4, the second switch SW2 and the fifth switch SW5 are short-circuited (turned on), and the first switch SW1, the third switch SW3, and the fourth switch SW4 may be open-circuited (turned off).

[0068] When the fifth switch SW5 is short-circuited, the second DC-DC converter 212 may supply the second power supply voltage Vs2 to the third node N3. When the second switch SW2 is short-circuited, the first DC-DC converter 211 may supply the first power supply voltage Vs1 to the second node N2. The connection between the first node N1 and the first DC-DC converter 211 may be cut off. The voltage level of the first power supply voltage Vs1 may be restored by the auxiliary current I_aux generated by the second LDO regulator 230. Therefore, although the connection between the first node N1 and the first DC-DC converter 211 is cut off, the first LDO regulator 240 may provide the output voltage Vout to the output node Nout by regulating the first power supply voltage Vs1 of the first node N1.

[0069] Figure 7 1 is a diagram showing a regulating circuit 100 according to an exemplary embodiment of the inventive concept. Figure 2 Description given.

[0070] refer to Figure 7 , the regulation circuit 100 may include a DC-DC converter 110, a switch circuit 120, a first LDO regulator 130, a second LDO regulator 140 and a current auxiliary circuit 150. Figure 2 The DC-DC converter 110 , the switch circuit 120 , the first LDO regulator 130 , and the second LDO regulator 140 are described in detail, so a description thereof is omitted.

[0071] The current assist circuit 150 may sense the output current I_out of the output node Nout, and may output the assist current I_ast to the first node N1 based on the sensed output current I_out. In an example embodiment, the current assist circuit 150 may include a current mirror circuit. During the transition from the first mode to the second mode, in order to provide an output current leakage to the output node, a charge may be stored in the capacitor of the first node N1, thereby compensating for a temporary decrease in the voltage level of the first node N1.

[0072] According to an example embodiment of the inventive concept, the current auxiliary circuit 150 may output the auxiliary current I_ast during a period in which the voltage level of the first node N1 is temporarily reduced. Therefore, the voltage level of the first node N1 may not be reduced, thereby maintaining the first power supply voltage. Therefore, despite the transition from the first mode to the second mode, a stable voltage with minimal ripple may be applied to the first LDO regulator 130, and the output voltage may also be stably maintained.

[0073] Figure 7An example embodiment is shown in which the current assist circuit 150 senses the current applied to the output node Nout. However, example embodiments of the inventive concept are not limited thereto. In some example embodiments, the current assist circuit 150 may sense the current applied to the first LDO regulator 130 or the current applied to the second node N2, and may apply the assist current I_ast to the first node N1 based on the sensed current.

[0074] Figure 8 is a timing diagram illustrating the operation of a regulating circuit according to an example embodiment of the inventive concept. Figure 8 The X-axis shows time and Figure 8 The Y-axis shows the potential of the node or the logic level of the signal. Figure 3 Description given.

[0075] refer to Figure 7 and Figure 8 , the dotted line shows the operation of the regulating circuit 100 without the current auxiliary circuit 150, and the solid line shows the operation of the regulating circuit 100 with the current auxiliary circuit 150. Figure 3 The figures are the same or basically similar, so their description will be omitted.

[0076] During the transition from the first mode Md1 to the second mode Md2, the second LDO regulator 140 may have a longer stabilization time. Therefore, when the current assist circuit 150 is omitted, the voltage levels of the first node N1 and the output node Nout may be temporarily reduced.

[0077] In example embodiments, the current assist circuit 150 may have a shorter current supply time than the second LDO regulator 140. Therefore, the current assist circuit 150 may output the auxiliary current I_ast to the first node N1 before the second LDO regulator 140 outputs the auxiliary current I_aux to the first node N1.

[0078] According to an example embodiment of the inventive concept, after the connection between the first node N1 and the DC-DC converter 110 is cut off, the first node N1 can uniformly maintain the voltage level by the auxiliary current I_ast. Then, the first node N1 can uniformly maintain the voltage level by the auxiliary current I_aux outputted stably. When a voltage with minimum ripple (or alternatively, a ripple with reduced height) is applied to the first node N1, the voltage level of the output node Nout can be stably maintained.

[0079] Fig. 9 2 is a block diagram showing a regulation circuit 200a according to an exemplary embodiment of the inventive concept. Figure 4 Description given.

[0080] refer to Fig. 9 , the regulation circuit 200a may include a first DC-DC converter 211a, a second DC-DC converter 212a, a third DC-DC converter 213a, a switch circuit 220a, a sixth switch SW6, and an LDO regulator 230a. Because the operations of the first DC-DC converter 211a, the second DC-DC converter 212a, the switch circuit 220a, and the LDO regulator 230a are similar to Figure 4 The first DC-DC converter 211, the second DC-DC converter 212, the switch circuit 220 and the first LDO regulator 230 are the same or substantially similar, so the previous reference is omitted. Figure 4 Description given.

[0081] The operation of the third DC-DC converter 213a is similar to Figure 4 The operation of the second LDO regulator 240 is controlled by the third DC-DC regulator 213a. In the second mode in which the connection between the first DC-DC regulator 211a and the first node N1 is cut off, the third DC-DC regulator 213a is connected to the first node N1 and the first power supply voltage can be provided to the first node N1. The third DC-DC regulator 213a can provide an output voltage (e.g., the first power supply voltage) that is the same as or substantially similar to the output voltage of the first DC-DC regulator 211a. Therefore, even when the first DC-DC regulator 211a does not provide a voltage to the LDO regulator 230a, the LDO regulator 230a can receive the first power supply voltage from the third DC-DC regulator 213a. In an example, the third DC-DC regulator 213a can be configured by a buck converter or a step-down converter.

[0082] The sixth switch SW6 can electrically connect or disconnect the third DC-DC regulator 213a to the first node N1 based on the sixth mode signal MS6. In an example embodiment, the sixth switch SW6 can operate complementarily with the first switch SW1. That is, when the first switch SW1 is open, the sixth switch SW6 can be short-circuited, and when the first switch SW1 is short-circuited, the sixth switch SW6 can be open.

[0083] Fig.10 is a flowchart illustrating a method of operating the regulating circuit 100 according to an example embodiment of the inventive concepts.

[0084] refer to Figure 2 and Fig.10In operation S110, the regulating circuit 100 may switch the output terminal of the DC-DC converter 110 from the first node N1 to the second node N2. When the connection between the first node N1 and the DC-DC converter 110 is cut off, in operation S120, the second LDO regulator 140 may apply the auxiliary current I_aux to the first node N1. The first LDO regulator 130 may provide an output voltage to the output node Nout by regulating the voltage of the first node N1.

[0085] Fig.11 is a flowchart illustrating a method of operating a regulating circuit according to an example embodiment of the inventive concept.

[0086] refer to Figure 4 and Fig.11 In the first mode, in operation S210, the regulating circuit 100 may connect the output terminal of the first DC-DC converter 211 to the first node N1, and may connect the output terminal of the second DC-DC converter 212 to the second node N2. In operation S220, the regulating circuit 100 may switch the output terminal of the first DC-DC converter 211 from the first node N1 to the third node N3. In the third mode, in operation S230, the regulating circuit 100 may switch the output terminal of the first DC-DC converter 211 from the third node N3 to the first node N1, and may switch the output terminal of the second DC-DC converter 212 from the second node N2 to the third node N3. In operation S240, the regulating circuit 100 may switch the output terminal of the first DC-DC converter 211 from the first node N1 to the second node N2.

[0087] Therefore, the first node N1 may have the first power supply voltage due to the auxiliary current I_aux generated by the second LDO regulator 230, the second node N2 may have the first power supply voltage through the first DC-DC converter 211, and the third node may have the second power supply voltage through the second DC-DC converter 212. Then, the first DC-DC converter 211 may switch from the second node N2 to the first node N1, and may operate in the first mode. Fig.12 is a flowchart illustrating a method of operating a current assist circuit according to an example embodiment of the inventive concept.

[0088] refer to Figure 7 and Fig.12 The current assist circuit 150 may sense an output current applied from or to an output node Nout of the regulating circuit 100. The current assist circuit 150 may apply an assist current I_ast to the first node N1 based on the sensed output current.

[0089] Fig.13 is a block diagram illustrating an electronic device 3000 according to an example embodiment of the inventive concept.

[0090] refer to Fig.13 , the electronic device 3000 may include a power supply 3100 , a central processing unit (CPU) 3200 , a signal processing unit 3300 , a user interface 3400 , a storage unit or memory 3500 , a device interface 3600 , and a bus 3700 .

[0091] The electronic device 3000 may be, for example, a computer, a mobile phone, a personal digital assistant (PDA), a portable media player (PMP), an MP3 player, a camera, a camcorder, a television, or a display device.

[0092] The power supply 3100 may generate a power supply voltage for the electronic device 3000, and may supply the generated power supply voltage to each element. The regulation circuit 100 according to the exemplary embodiment of the inventive concept may be applied to the power supply 3100. For example, the power supply 3100 may include a plurality of LDO regulators, and may stably manage the voltage level of the output voltage even when the DC-DC converter supplies a voltage to another node (in other words, even when the DC-DC converter does not supply a voltage to the first node).

[0093] The CPU 3200 may control the electronic device 3000. For example, the CPU 3200 may control elements of the electronic device 3000 based on information input through the user interface 3400.

[0094] The signal processing unit 3300 may process a signal received through the device interface 3600 or a signal read from the storage unit 3500 according to a determined standard. For example, the signal processing unit 3300 may process a video signal or an audio signal.

[0095] The user interface 3400 may be an input device for user setting information for setting functions of the electronic device 3000 and operating the electronic device 3000. The storage unit 3500 may store various information items required to operate the electronic device 3000. In addition, data received through the device interface 3600 or data items processed by the electronic device 3000 may be stored in the storage unit 3500.

[0096] The device interface 3600 may perform data communication with an external device connected to the electronic device 3000 in a wired or wireless manner. The bus 3700 may transfer information between elements of the electronic device 3000.

[0097] While the inventive concept has been shown and described in detail with reference to certain example embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the claims.

Claims

1. A regulating circuit, comprising: a first DC-DC converter configured to generate a first power supply voltage, apply the first power supply voltage to a first node via a first switch in a first mode, and apply the first power supply voltage to a second node via a second switch in a second mode; a first low dropout output (LDO) regulator connected to the first node, the first LDO regulator being configured to be selectively connected to the first DC-DC converter via the first switch in the first mode to receive the first power supply voltage, and the first LDO regulator being further configured to provide an output voltage to an output node by regulating the voltage of the first node in the first mode and the second mode; as well as The second LDO regulator is directly connected to the first node, and the second LDO regulator is configured to provide an auxiliary current to the first node in the second mode.

2. The regulating circuit according to claim 1, further comprising: a control logic configured to generate a first mode signal corresponding to the first mode, a second mode signal corresponding to the second mode, and a third mode signal corresponding to the third mode, wherein the first switch is configured to electrically connect or disconnect the first node and the first DC-DC converter based on the first mode signal; The second switch is configured to electrically connect or disconnect the second node and the first DC-DC converter based on the second mode signal; and The first DC-DC converter is further configured to apply the first power supply voltage to a third node via a third switch based on the third mode signal.

3. The regulating circuit according to claim 2, further comprising: The second DC-DC converter is configured to provide a second power supply voltage to the second node via a fourth switch in the first mode, and to provide the second power supply voltage to the third node via a fifth switch in the second mode.

4. The regulating circuit according to claim 3, wherein: The fourth switch is configured to electrically connect or disconnect the second node from the second DC-DC converter based on the first mode signal or the third mode signal; as well as The fifth switch is configured to electrically connect or disconnect the third node and the second DC-DC converter based on a fourth mode signal corresponding to a fourth mode or the second mode signal.

5. The regulating circuit according to claim 3, wherein: The regulating circuit is configured to receive a second mode signal and a third mode signal generated based on a power supply voltage request signal of at least one of the second node or the third node.

6. The regulating circuit according to claim 5, further comprising: A switch circuit including the first switch and the second switch, the switch circuit being configured to connect or disconnect the first DC-DC converter with the second node based on the second mode signal, and to connect or disconnect the second DC-DC converter with the second node based on the first mode signal or the third mode signal.

7. The regulating circuit according to claim 1, further comprising: A current assist circuit is connected to the first node, and the current assist circuit is configured to provide the auxiliary current to the first node when the first DC-DC converter does not apply the first power supply voltage to the first node via the first switch but applies the first power supply voltage to the second node via the second switch.

8. The regulating circuit according to claim 7, wherein: The current assist circuit is further configured to sense a current of the output node and determine a current level of the assist current based on the sensed current.

9. The regulating circuit according to claim 1, wherein: The first LDO regulator and the second LDO regulator include different types of metal oxide semiconductor (MOS) transistors.

10. The regulating circuit according to claim 9, wherein: The first LDO regulator includes at least one n-channel metal oxide semiconductor (NMOS) transistor, and The second LDO regulator includes at least one p-channel metal oxide semiconductor (PMOS) transistor.

11. A regulating circuit, comprising: A first DC-DC converter configured to provide a first power supply voltage; a switch circuit, comprising a first switch and a second switch, wherein the switch circuit is configured to connect or disconnect the output terminal of the first DC-DC converter with a first node via the first switch based on a first mode setting signal, or to connect or disconnect the output terminal of the first DC-DC converter with a second node via the second switch based on a second mode setting signal; a first low dropout output (LDO) regulator configured to be selectively connected to the first DC-DC converter via the first switch, and the first LDO regulator is further configured to provide an output voltage to an output node by regulating the voltage of the first node; as well as A second LDO regulator is directly connected to the first node, and the second LDO regulator is configured to increase the voltage level of the first node to the voltage level of the first power supply voltage by supplying an auxiliary current to the first node when the first DC-DC converter is connected to the second node.

12. The regulating circuit according to claim 11, further comprising: A second DC-DC converter is configured to provide a second power supply voltage, wherein the switch circuit further includes a fourth switch and a fifth switch, and the switch circuit is further configured to connect the output terminal of the second DC-DC converter to the second node via the fourth switch based on a fourth mode setting signal, or to connect the output terminal of the second DC-DC converter to the third node via the fifth switch based on a fifth mode setting signal.

13. The regulating circuit according to claim 12, wherein: The switch circuit further includes a third switch configured to connect or disconnect the output terminal of the first DC-DC converter with the third node based on a third mode setting signal.

14. The regulating circuit according to claim 11, further comprising: The current assist circuit is configured to sense a current of the output node and apply the assist current to the first node based on the sensed current.

15. A method of operating a regulation circuit for supplying an output voltage by regulating a voltage of a first node, the method comprising: Switching the output terminal of the first DC-DC converter from the first node to the second node based on a first switch connected between the output terminal of the first DC-DC converter and the first node and a second switch connected between the output terminal of the first DC-DC converter and the second node; applying an auxiliary current to the first node by a first low dropout output (LDO) regulator directly connected to the first node; as well as The output voltage is supplied by regulating the voltage of the first node by a second LDO regulator.

16. The method according to claim 15, further comprising: switching the output terminal of the second DC-DC converter from the third node to the second node; as well as The output terminal of the first DC-DC converter is switched from the second node to the first node.

17. The method according to claim 16, further comprising: The assist current generated by the current assist circuit is applied to the first node.

18. The method of claim 17, wherein applying the auxiliary current comprises: sensing a current at an output node of the regulation circuit; as well as The auxiliary current is applied to the first node, wherein a current level of the auxiliary current is determined based on the sensed current of the output node.

19. The method according to claim 17, wherein: The applying of the auxiliary current is performed after switching the output terminal of the first DC-DC converter from the first node to the second node.

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