Low dropout regulator and operating method thereof

Abstract

A low dropout regulator (abbreviated as LDO) and a method of operating the same are provided. The LDO voltage regulator can comprise a reference voltage generating circuit, an operational amplifier, a transistor and a multi-stage configuration switching control circuit. The operating method may include performing a first configuration operation to enable a first dedicated current path corresponding to a first stage to allow a target reference voltage used in an LDO voltage stabilization mode to reach a first predetermined range after the first configuration operation is performed; performing a second configuration operation to enable a second dedicated current path corresponding to a second stage to allow the target reference voltage to reach a second predetermined range after the second configuration operation is performed; and performing a third configuration operation to allow the target reference voltage to be used as a reference voltage input to the operational amplifier in the LDO voltage stabilization mode after the third configuration operation is performed.

Description

[Technical field]

[0001] The present invention relates to circuit design, and more particularly to a low-dropout (LDO) regulator and an operating method thereof. [Background technology]

[0002] According to the related art, a voltage regulator, such as a conventional low dropout regulator (LDO regulator; also referred to as LDO regulator / regulator), may be provided in an electronic device to generate a stable voltage based on a source voltage. For example, the source voltage may be noisy, and certain circuits in the electronic device may use the stable voltage to avoid being affected by the above noise. When these circuits are not needed, the electronic device may temporarily shut down the conventional low dropout regulator to save power. When these circuits are needed, the electronic device may turn on the conventional low dropout regulator. The time it takes for the conventional low dropout regulator to reach a stable state may be quite long. One or more suggestions may be made in the related art to try to solve this problem, but it does not seem to really solve this problem. For example, the average time it takes for the conventional low dropout regulator to reach a stable state may exceed 10 microseconds (μs), and the electronic device may need to wait for a longer time, such as 20 milliseconds (ms) to avoid any errors caused by any changes in the time to reach a stable state, which may be too long for the requirements of high-speed operation. Therefore, a novel method and related architecture are needed to solve this problem without introducing any side effects or in a manner that is unlikely to introduce side effects. [Summary of the invention]

[0003] One of the objectives of the present invention is to provide a low dropout voltage regulator and an operating method thereof to solve the above problems and improve the overall efficiency.

[0004] At least one embodiment of the present invention provides a low dropout regulator. The low dropout regulator may include a reference voltage generating circuit, an operational amplifier coupled to the reference voltage generating circuit, a transistor coupled to the operational amplifier, and a multi-stage configuration switching control circuit coupled to the reference voltage generating circuit, the operational amplifier and the transistor. The reference voltage generating circuit can be used to generate at least one reference voltage; the operational amplifier can be used to control an output voltage of the low dropout regulator by negative feedback in a low dropout regulation mode of the low dropout regulator; the transistor can be used to generate the output voltage of the low dropout regulator under the control of the operational amplifier in the low dropout regulation mode for further use; and the multi-stage configuration switching control circuit can be used to perform multi-stage configuration switching control to perform multiple configuration operations on the circuit architecture of the low dropout regulator. For example, the multi-stage configuration switching control circuit performs a first configuration operation on the circuit architecture of the low-dropout regulator to enable a first dedicated current path corresponding to a first stage, so as to allow a target reference voltage used in the low-dropout regulation mode to reach a first predetermined range after performing the first configuration operation; the multi-stage configuration switching control circuit performs a second configuration operation on the circuit architecture of the low-dropout regulator to enable a second dedicated current path corresponding to a second stage, so as to allow the target reference voltage to reach a second predetermined range after performing the second configuration operation; and the multi-stage configuration switching control circuit performs a third configuration operation on the circuit architecture of the low-dropout regulator to allow the target reference voltage to be used as a reference voltage input to the operational amplifier in the low-dropout regulation mode after performing the third configuration operation.

[0005] At least one embodiment of the present invention provides an operating method, which can be applied to the above-mentioned low-dropout regulator. The operating method may include: using the multi-stage configuration switching control circuit to perform the first configuration operation on the circuit architecture of the low-dropout regulator to enable the first dedicated current path corresponding to the first stage, so as to allow the target reference voltage used in the low-dropout regulation mode to reach the first predetermined range after performing the first configuration operation; using the multi-stage configuration switching control circuit to perform the second configuration operation on the circuit architecture of the low-dropout regulator to enable the second dedicated current path corresponding to the second stage, so as to allow the target reference voltage to reach the second predetermined range after performing the second configuration operation; and using the multi-stage configuration switching control circuit to perform the third configuration operation on the circuit architecture of the low-dropout regulator to allow the target reference voltage to be used as a reference voltage input to the operational amplifier in the low-dropout regulation mode after performing the third configuration operation.

[0006] The low dropout voltage regulator and the operating method thereof of the present invention can perform preliminary setting of the reference voltage through multi-stage control, and in particular, accelerate the preliminary setting of the reference voltage so that the target reference voltage quickly reaches a predetermined voltage level. In addition, the low dropout voltage regulator and the operating method thereof of the present invention can solve the problems of the related art without introducing any side effects or in a manner that is unlikely to introduce side effects.

Brief Description of the Drawings

[0007] Figure 1 FIG. 4 is a schematic diagram of a low dropout voltage regulator according to an embodiment of the present invention. Figure 2 FIG. 4 is a schematic diagram of a low dropout voltage regulator according to another embodiment of the present invention. Figure 3A According to an embodiment of the present invention, Figure 1 The circuit architecture shown is configured in a first stage. Figure 3B According to an embodiment of the present invention, Figure 2 The circuit architecture shown is configured in this first phase. Figure 4A According to an embodiment of the present invention, Figure 1 The circuit architecture shown is configured in a second stage. Figure 4B According to an embodiment of the present invention, Figure 2 The circuit architecture shown is configured in this second phase. Figure 5A According to an embodiment of the present invention, Figure 1 The circuit architecture shown is configured in a third phase. Figure 5B According to an embodiment of the present invention, Figure 2 The circuit architecture shown is configured in this third phase. Figure 6 A timing diagram of related signals is depicted according to an embodiment of the present invention. Figure 7 According to an embodiment of the present invention, a working process of an operating method of a low dropout voltage regulator is described. [Specific implementation method]

[0008] Multiple embodiments of the present invention provide a low-dropout regulator that can perform preliminary setting of a reference voltage through multi-stage control, so that the low-dropout regulator can reach a stable state immediately after being turned on, so as to allow an electronic device using the low-dropout regulator to immediately use the low-dropout regulator to improve overall efficiency. For example, an output voltage of the low-dropout regulator can quickly reach a predetermined voltage level to allow at least one internal circuit (e.g., one or more internal circuits) of the electronic device to operate according to the output voltage that has reached the predetermined voltage level. When the at least one internal circuit is not needed, the electronic device can temporarily shut down the low-dropout regulator to save power. When the at least one internal circuit is needed, the electronic device can turn on the low-dropout regulator again. Similarly, the low-dropout regulator can reach a stable state immediately after being turned on again, so as to allow the electronic device (or the at least one internal circuit therein) to immediately use the low-dropout regulator to improve overall efficiency.

[0009] Figure 1 The schematic diagram of a low dropout regulator 100A according to an embodiment of the present invention is shown, wherein the low dropout regulator 100A can be used as an example of the above-mentioned low dropout regulator of the present invention. The low dropout regulator 100A can include a reference voltage generating circuit 101, an operational amplifier 104 (labeled "OPA" for simplicity), a transistor 106, a multi-stage configuration switching control circuit 110, an automatic fast-set (AF) control circuit 120 (labeled "AF control circuit" for simplicity), a current control circuit 130, a plurality of resistors {R1, R2}, a plurality of capacitors {C1, C2, C3}, a plurality of switch circuits {SW1, SW2, SW3, SW4} and a power line PWR for providing a power supply voltage VDD, and the above-listed components can be coupled to each other as shown in FIG. Figure 1 As shown, the reference voltage generating circuit 101 may include a reference voltage generator 102 and a reference voltage converter 103, the transistor 106 may be implemented by a metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Field Effect Transistor, referred to as MOSFET) such as an N-type MOSFET MN1, and among the multiple input terminals of the operational amplifier 104, a first input terminal and a second input terminal for receiving input voltages VIP and VIN respectively may represent a positive input terminal and a negative input terminal respectively (respectively marked with "+" and "-" in the triangle "LDO OP" representing the operational amplifier for simplicity), but the present invention is not limited thereto. According to some embodiments, Figure 1The circuit architecture shown may be varied.

[0010] Figure 2 FIG. 1 is a schematic diagram of a low-dropout voltage regulator 100B according to another embodiment of the present invention, wherein the low-dropout voltage regulator 100B can be used as an example of the above-mentioned low-dropout voltage regulator of the present invention. The low-dropout voltage regulator 100B can include a reference voltage generating circuit 101, an operational amplifier 104 (labeled "OPA" for simplicity), a transistor 106, a multi-stage configuration switching control circuit 110, an automatic fast setting control circuit 120 (labeled "AF control circuit" for simplicity), a current control circuit 130, resistors {R1, R2}, capacitors {C1, C2, C3}, switch circuits {SW1, SW2, SW3, SW4} and a power line PWR, and the above-listed components can be coupled to each other as shown in FIG. Figure 2 As shown, the transistor 106 can be implemented by the MOSFET, such as a P-type MOSFET MP1, and among the multiple input terminals of the operational amplifier 104, the first input terminal and the second input terminal for receiving the input voltages VIP and VIN respectively can represent the negative input terminal and the positive input terminal respectively (respectively marked with "-" and "+" in the triangle "LDO OP" representing the operational amplifier for simplicity), but the present invention is not limited thereto. According to some embodiments, Figure 2 The circuit architecture shown may be varied.

[0011] like Figure 1 and Figure 2 As shown in any of the figures in the drawings, the low dropout regulator (e.g., low dropout regulator 100A or 100B) of the present invention can utilize a reference voltage generating circuit 101 to generate at least one reference voltage, utilize an operational amplifier 104 to control the output voltage LDO_OUT of the low dropout regulator through negative feedback in a low dropout regulation mode of the low dropout regulator, and utilize a transistor 106 to generate the output voltage LDO_OUT of the low dropout regulator under the control of the operational amplifier 104 in the low dropout regulation mode for further use. In particular, the low dropout regulator (e.g., low dropout regulator 100A or 100B) of the present invention can utilize a multi-stage configuration switching control circuit 110 to perform multi-stage configuration switching control to control the circuit architecture of the low dropout regulator (e.g., Figure 1 or Figure 2 For example, the related operations for the multi-stage configuration switching control may include:

[0012] (1) The multi-stage configuration switching control circuit 110 may perform a first configuration operation on the circuit architecture of the low dropout regulator to enable a first dedicated current path corresponding to a phase Phase 1 (e.g., a current path starting from the power line PWR, passing through the current control circuit 130 and the switch circuit SW3 and reaching the upper terminal of the capacitor C1), so as to allow a target reference voltage VREF used in the low dropout regulation mode to reach a first predetermined range after performing the first configuration operation;

[0013] (2) The multi-stage configuration switching control circuit 110 may perform a second configuration operation on the circuit architecture of the low dropout regulator to enable a second dedicated current path corresponding to a phase Phase 2 (e.g., a current path starting from the reference voltage converter 103, passing through the switch circuit SW1 and reaching the upper terminal of the capacitor C1) to allow the target reference voltage VREF to reach a second predetermined range after performing the second configuration operation; and

[0014] (3) The multi-stage configuration switching control circuit 110 can perform a third configuration operation on the circuit architecture of the low dropout regulator to allow the target reference voltage VREF to be used as the reference voltage VREF input to the operational amplifier 104 in the low dropout regulation mode after performing the third configuration operation;

[0015] However, the present invention is not limited thereto. According to some embodiments, the operations related to the multi-stage configuration switching control may be changed.

[0016] In addition, reaching the first predetermined range may include exceeding a voltage level VB, and reaching the second predetermined range may include approaching a voltage level VA, wherein the voltage level VB is less than the voltage level VA, and in particular, slightly less than the voltage level VA. For example, the at least one reference voltage may include a reference voltage VR1 equal to the voltage level VA and a reference voltage VR2 equal to the voltage level VB. The reference voltage generator 102 may generate the reference voltage VR1, and the reference voltage converter 103 may perform voltage conversion on the reference voltage VR1 to generate the reference voltage VR2, and control the difference (VR1-VR2) between the reference voltage VR1 and the reference voltage VR2 to be equal to a predetermined difference (VA-VB), that is, the difference (VA-VB) between the voltage level VA and the voltage level VB, so that the multi-stage configuration switching control circuit 110 can accelerate the setting of the target reference voltage VREF.

[0017] In addition, the multi-stage configuration switching control circuit 110 can generate a plurality of control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} to control the switch circuits {SW1, SW2, SW3, SW4} to perform any one of the plurality of configuration operations (e.g., the first configuration operation, the second configuration operation, and the third configuration operation) on the circuit architecture of the low dropout regulator, wherein the control signal VAUTO_FASTSET_B can represent an inverse signal of the control signal VAUTO_FASTSET. Figure 1 and Figure 2 As shown in any of the figures, among the multiple input terminals of the operational amplifier 104, the first input terminal for receiving the input voltage VIP can be coupled to the output terminal of the reference voltage generator 102 through the resistor R1, and after performing the second configuration operation or the third configuration operation, the second input terminal for receiving the input voltage VIN can be coupled to a first terminal of the transistor 106 through a negative feedback path (on which the switch circuit SW4 is disposed), for example, among the multiple terminals of the transistor 106, the lower terminal for outputting the output voltage LDO_OUT of the low dropout regulator. Figure 1 Taking the circuit structure shown in the figure as an example, the second input terminal for receiving the input voltage VIN can be coupled to the source terminal of the N-type MOSFET MN1 through the negative feedback path. Figure 2 Taking the circuit structure shown as an example, the second input terminal for receiving the input voltage VIN can be coupled to the drain terminal of the P-type MOSFET MP1 through the negative feedback path.

[0018] In the circuit architecture of the low dropout regulator (for example: Figure 1 or Figure 2In the circuit architecture shown in FIG. 1 , the reference voltage generator 102 may be implemented by a bandgap reference voltage generating circuit or the like, the reference voltage converter 103 may be implemented by a voltage divider resistor, a diode-connected transistor such as a diode-connected MOSFET (e.g., a MOSFET whose gate terminal and drain terminal are connected to each other), or the like, the multi-stage configuration switching control circuit 110 and the automatic fast setting control circuit 120 may be implemented by a logic circuit or the like, the current control circuit 130 may be implemented by various transistors such as a MOSFET (e.g., an N-type MOSFET and / or a P-type MOSFET), a resistor with a fixed resistance value, a variable resistor, or the like, and the switch circuits {SW1, SW2, SW3, SW4} may be implemented by various transistors such as a MOSFET (e.g., an N-type MOSFET and / or a P-type MOSFET), or the like, but the present invention is not limited thereto.

[0019] Figure 3A According to an embodiment of the present invention, Figure 1 The circuit architecture shown is configured in Phase 1. Figure 1 Under the control of the multi-stage configuration switching control circuit 110 (or the control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} generated and outputted by it), the switch circuits {SW1, SW2, SW3, SW4} can be operated as follows Figure 3A As shown, the multi-stage configuration switching control circuit 110 allows the circuit architecture of the low dropout regulator 100A to perform the first configuration operation. For example, the multi-stage configuration switching control circuit 110 can turn on the switch circuits SW2 and SW3 and turn off the switch circuits SW1 and SW4.

[0020] Figure 3B According to an embodiment of the present invention, Figure 2 The circuit architecture shown is configured in Phase 1. Figure 2 Under the control of the multi-stage configuration switching control circuit 110 (or the control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} generated and outputted by it), the switch circuits {SW1, SW2, SW3, SW4} can be operated as follows Figure 3B As shown, the multi-stage configuration switching control circuit 110 allows the circuit architecture of the low dropout regulator 100B to perform the first configuration operation. For example, the multi-stage configuration switching control circuit 110 can turn on the switch circuits SW2 and SW3 and turn off the switch circuits SW1 and SW4.

[0021] like Figure 3Aand Figure 3B As shown in any of the figures in , performing the first configuration operation may include:

[0022] (1) enabling the first dedicated current path corresponding to phase Phase 1 (e.g., a current path starting from the power line PWR, passing through the current control circuit 130 and the switch circuit SW3 and reaching the upper terminal of the capacitor C1) to perform a first preliminary setting operation on the target reference voltage VREF according to the power voltage VDD, so as to accelerate the target reference voltage VREF to reach the first predetermined range;

[0023] (2) coupling the plurality of input terminals (e.g., the first input terminal and the second input terminal for receiving the input voltages VIP and VIN, respectively) of the operational amplifier 104 to the target reference voltage VREF and the reference voltage VR2, respectively, so that the operational amplifier 104 acts as a comparator for comparing the target reference voltage VREF with the reference voltage VR2; and

[0024] (3) disconnecting the negative feedback path between the second input terminal of the operational amplifier 104 (e.g., the second input terminal for receiving the input voltage VIN) and the first terminal of the transistor 106 (e.g., the lower terminal for outputting the output voltage LDO_OUT of the low dropout regulator) to disable the negative feedback path used in the low dropout regulation mode;

[0025] In the low dropout voltage regulation mode, the first terminal of the transistor 106 is used to output the output voltage LDO_OUT of the low dropout voltage regulator, but the present invention is not limited thereto. In addition, the automatic fast setting control circuit 120 can be coupled to an output terminal of the operational amplifier 104 (for example, the output terminal for generating the output voltage VOP), and can receive a comparison result of the target reference voltage VREF and the reference voltage VR2 from the operational amplifier 104 to generate a control signal AF according to the comparison result. The current control circuit 130 can be coupled to the automatic fast setting control circuit 120, and can control the current I on the first dedicated current path according to the control signal AF to accelerate the target reference voltage VREF to reach the first predetermined range.

[0026] Figure 4A According to an embodiment of the present invention, Figure 1 The circuit architecture shown is configured in Phase 2. Figure 1 Under the control of the multi-stage configuration switching control circuit 110 (or the control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} generated and outputted by it), the switch circuits {SW1, SW2, SW3, SW4} can be operated as follows Figure 4A As shown, the multi-stage configuration switching control circuit 110 allows the circuit architecture of the low dropout regulator 100A to perform the second configuration operation. For example, the multi-stage configuration switching control circuit 110 can turn on the switch circuits SW1 and SW4 and turn off the switch circuits SW2 and SW3.

[0027] Figure 4B According to an embodiment of the present invention, Figure 2 The circuit architecture shown is configured in Phase 2. Figure 2 Under the control of the multi-stage configuration switching control circuit 110 (or the control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} generated and outputted by it), the switch circuits {SW1, SW2, SW3, SW4} can be operated as follows Figure 4B As shown, the multi-stage configuration switching control circuit 110 allows the circuit architecture of the low dropout regulator 100B to perform the second configuration operation. For example, the multi-stage configuration switching control circuit 110 can turn on the switch circuits SW1 and SW4 and turn off the switch circuits SW2 and SW3.

[0028] like Figure 4A and Figure 4B As shown in any of the figures in , performing the second configuration operation may include:

[0029] (1) stopping coupling the second input terminal (e.g., the second input terminal for receiving the input voltage VIN) of the operational amplifier 104 to the reference voltage VR2, and coupling the second input terminal of the operational amplifier 104 to the first terminal (e.g., the lower terminal for outputting the output voltage LDO_OUT of the low dropout regulator) of the transistor 106 to enable the negative feedback path used in the low dropout regulation mode;

[0030] (2) disabling the first dedicated current path corresponding to phase Phase 1 (e.g., a current path starting from the power line PWR, passing through the current control circuit 130 and the switch circuit SW3 and reaching the upper terminal of the capacitor C1), wherein the first dedicated current path may be coupled between the power line PWR and the first input terminal of the operational amplifier 104 (e.g., the first input terminal for receiving the input voltage VIP) in phase Phase 1, and may no longer be coupled between the power line PWR and the first input terminal of the operational amplifier 104 in phase Phase 2; and

[0031] (3) enabling the second dedicated current path corresponding to phase Phase2 (e.g., a current path starting from the reference voltage converter 103, passing through the switch circuit SW1 and reaching the upper terminal of the capacitor C1) to couple the first input terminal of the operational amplifier 104 (e.g., the first input terminal for receiving the input voltage VIP) to the reference voltage VR2, so as to forcibly set the target reference voltage VREF to be equal to the reference voltage VR2, so as to reduce any deviation of the target reference voltage VREF generated in phase Phase1 relative to the second predetermined range, so as to accelerate the target reference voltage VREF to reach the second predetermined range;

[0032] However, the present invention is not limited thereto. In addition, the time for enabling the second dedicated current path corresponding to phase Phase2 may include at least a portion (e.g., a portion or the entirety) of phase Phase2. For example, the time for enabling the second dedicated current path corresponding to phase Phase2 may include a portion of phase Phase2, and in particular, reach a predetermined time length (e.g., the maximum response time of the switch circuit SW1). For another example, the time for enabling the second dedicated current path corresponding to phase Phase2 may include the entirety of phase Phase2.

[0033] Figure 5A According to an embodiment of the present invention, Figure 1 The circuit architecture shown is configured in Phase 3. Figure 1 Under the control of the multi-stage configuration switching control circuit 110 (or the control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} generated and outputted by it), the switch circuits {SW1, SW2, SW3, SW4} can be operated as follows Figure 5A As shown, the multi-stage configuration switching control circuit 110 allows the circuit architecture of the low dropout regulator 100A to perform the third configuration operation. For example, the multi-stage configuration switching control circuit 110 can turn on the switch circuit SW4 and turn off the switch circuits SW1, SW2 and SW3.

[0034] Figure 5B According to an embodiment of the present invention, Figure 2 The circuit architecture shown is configured in Phase 3. Figure 2 Under the control of the multi-stage configuration switching control circuit 110 (or the control signals {VREF_SHORT, VAUTO_FASTSET, VAUTO_FASTSET_B} generated and outputted by it), the switch circuits {SW1, SW2, SW3, SW4} can be operated as follows Figure 5BAs shown, the multi-stage configuration switching control circuit 110 allows the circuit architecture of the low dropout regulator 100B to perform the third configuration operation. For example, the multi-stage configuration switching control circuit 110 can turn on the switch circuit SW4 and turn off the switch circuits SW1, SW2 and SW3.

[0035] like Figure 5A and Figure 5B As shown in any of the figures in , performing the third configuration operation may include:

[0036] (1) disabling the second dedicated current path corresponding to Phase 2 (e.g., a current path starting from the reference voltage converter 103, passing through the switch circuit SW1 and reaching the upper terminal of the capacitor C1), wherein the second dedicated current path is no longer used to couple the first input terminal of the operational amplifier 104 (e.g., the first input terminal for receiving the input voltage VIP) to the reference voltage VR2 in Phase 3;

[0037] After performing the second configuration operation, the multi-stage configuration switching control circuit 110 may immediately perform the third configuration operation, so that the third configuration operation is immediately after the second configuration operation, but the present invention is not limited thereto.

[0038] Figure 6 A timing diagram is shown according to an embodiment of the present invention depicting related signals such as a power control signal POW_LDO, a system control signal FASTSET, reference voltages VR1 and VR2, a target reference voltage VREF, an output voltage VOP of the operational amplifier 104, control signals VAUTO_FASTSET and VREF_SHORT, and an output voltage LDO_OUT of the low dropout regulator, wherein voltage levels VA and VB and phases Phase1, Phase2 and Phase3 together with sub-phases Phase3a and Phase3b of Phase3 can be depicted in Figure 6For ease of understanding, but the present invention is not limited thereto. According to some embodiments, the related signals, voltage levels VA and VB, phases Phase1, Phase2 and Phase3, and / or sub-phases Phase3a and Phase3b may be changed. In addition, an upper circuit (e.g., at least one microcontroller or processor) in the electronic device may generate a power control signal POW_LDO to control the power supply of the low-dropout regulator (e.g., low-dropout regulator 100A or 100B) of the present invention, so as to start the low-dropout regulator at the start time point of phase Phase1 to provide the power supply voltage VDD through the power line PWR, and may generate a system control signal FASTSET to control the above-mentioned at least one internal circuit to use the low-dropout regulator in the sub-phase Phase3b. In some embodiments, after the start time point of phase Phase2, the multi-phase configuration switching control circuit 110 can control the control signal VREF_SHORT to perform state transition accordingly according to the system control signal FASTSET (or its state transition), which means that phase Phase2 can be changed to be longer so that phase Phase3 is equal to sub-phase Phase3b and the length of sub-phase Phase3a is equal to zero, but the present invention is not limited thereto. Figure 6 As shown, the multi-stage configuration switching control circuit 110 can control the time difference between the two state transition time points of the control signal VREF_SHORT (or the respective time points of its rising edge and falling edge) to be very small, for example, by controlling this time difference to be equal to a predetermined delay time (for example: 0.3μs) through a delay circuit.

[0039] For example, the duration of phase Phase1 may be less than 3 μs, which is less than the time it takes for the conventional low dropout regulator to reach a stable state (e.g., more than 10 μs). After performing the first configuration operation, the multi-stage configuration switching control circuit 110 may utilize the first dedicated current path to perform the first preliminary setting operation on the target reference voltage VREF according to the power supply voltage VDD. In particular, in phase Phase1, the capacitor C1 is charged with a current I on the first dedicated current path (e.g., a large current that is much larger than the maximum output current of the reference voltage generator 102 and much larger than the maximum output current of the reference voltage converter 103) to accelerate the target reference voltage VREF to reach the first predetermined range (e.g., exceeding the voltage level VB). In addition, after performing the second configuration operation, the multi-stage configuration switching control circuit 110 can use the second dedicated current path to forcibly set the target reference voltage VREF to be equal to the reference voltage VR2, and in particular, in Phase 2, by turning on the switch circuit SW1 to achieve a short circuit so that VREF=VR2, so as to reduce any deviation of the target reference voltage VREF generated in Phase 1 relative to the second predetermined range to accelerate the target reference voltage VREF to reach the second predetermined range (e.g., approach the voltage level VA). In addition, after performing the second configuration operation, the multi-stage configuration switching control circuit 110 can immediately perform the third configuration operation, and in particular, in Phase 3, by turning off the switch circuit SW1 to cancel the short circuit so as to allow the current from the reference voltage generator 102 and through the resistor R1 to charge the capacitor C1, so as to control the target reference voltage VREF to reach the second predetermined range (e.g., approach the voltage level VA) earlier.

[0040] The low dropout regulator of the present invention (e.g., low dropout regulator 100A or 100B) can be ready for use in a very short time after being turned on, so its efficiency is better than that of a conventional low dropout regulator. For a conventional low dropout regulator, the time difference between the state transition time of the system control signal FASTSET (e.g., the time of its falling edge) and the state transition time of the power control signal POW_LDO (e.g., the time of its rising edge) may need to be set to at least 20ms to ensure that the output voltage of the conventional low dropout regulator becomes stable. For the low dropout regulator of the present invention, this time difference can be greatly shortened. Figure 6Taking the timing diagram as an example, the duration of phase Phase1 can be less than 3 μs, the duration of phase Phase2 can be much less than 3 μs, and the total duration of phase Phase2 and sub-phase Phase3a can be approximately equal to 4.5 μs, which means that the low dropout regulator of the present invention can be ready for use in 7.5 μs (e.g., (3+4.5) μs=7.5 μs) or shorter. Since the target reference voltage VREF can be controlled to be very close to the voltage level VA by turning on the switch circuit SW1 in phase Phase2 to make VREF=VR2, the target reference voltage VREF can quickly reach the voltage level VA after the short circuit is canceled. Therefore, the time difference between the state transition time of the system control signal FASTSET (e.g., the time of its falling edge) and the state transition time of the power control signal POW_LDO (e.g., the time of its rising edge) can be controlled to be within 7.5 μs or even shorter, but the present invention is not limited thereto. When a more conservative control is adopted, this time difference can be arbitrarily set larger, for example, set to 5ms, which is still less than the 20ms required by the traditional low-dropout regulator.

[0041] In addition, in order to save area and reduce power consumption, the power consumption of the reference voltage generator in the conventional low dropout regulator can be quite limited, and the relevant resistance value R / capacitance value C for more stringent product specifications is usually larger and the stabilization time is also longer, which may cause the conventional low dropout regulator to be unable to meet the requirements of high-speed operation. For the same stringent product specifications, the low dropout regulator of the present invention can perform the multi-stage configuration switching control to easily meet the requirements of high-speed operation, for example, when the maximum output current of the reference voltage generating circuit 101 (or the reference voltage generator 102 or the reference voltage converter 103 therein) can be quite limited, and the resistance value R1 of the resistor R1 and / or the capacitance value C1 of the capacitor C1 can be increased and the stabilization time of the target reference voltage VREF can be correspondingly increased. The low dropout regulator can use a predetermined difference (VA-VB) that has been designed to be very small so that the target reference voltage VREF immediately reaches the voltage level VA after quickly exceeding the voltage level VB and then immediately returning to the voltage level VB.

[0042] Figure 7 According to an embodiment of the present invention, a working process of an operating method of a low dropout regulator (eg, the low dropout regulator 100A or 100B) is described.

[0043] In step S11, the low dropout regulator can utilize the multi-stage configuration switching control circuit 110 to perform the first configuration operation on the circuit architecture of the low dropout regulator to enable the first dedicated current path corresponding to a first stage (e.g., stage Phase 1) to allow the target reference voltage VREF used in the low dropout regulation mode to reach the first predetermined range after performing the first configuration operation.

[0044] In step S12, the low dropout regulator can utilize the multi-stage configuration switching control circuit 110 to perform the second configuration operation on the circuit architecture of the low dropout regulator to enable the second dedicated current path corresponding to a second stage (e.g., stage Phase 2) to allow the target reference voltage VREF to reach the second predetermined range after performing the second configuration operation.

[0045] In step S13, the low dropout regulator can utilize the multi-stage configuration switching control circuit 110 to perform the third configuration operation on the circuit architecture of the low dropout regulator to allow the target reference voltage VREF to be used as the reference voltage VREF input to the operational amplifier 104 in the low dropout regulation mode after performing the third configuration operation.

[0046] The low dropout regulator can be based on Figure 7 The overall efficiency of the electronic device can be greatly improved by operating the workflow shown in the figure. For better understanding, it is assumed that in one embodiment the low dropout regulator can be configured to temporarily skip steps S11 and / or S12, but the present invention is not limited thereto. For example, in the case where the execution of steps S11 and S12 is skipped and the configuration shown in FIG. 5A / 5B is directly performed, it takes a long time (e.g., a time corresponding to the time constant (R1*C1)) to charge the capacitor C1 using only the current from the reference voltage generator 102 and through the resistor R1 so that the target reference voltage VREF reaches the voltage level VA, because the capacitor C1 can be very large (e.g., in order to filter out noise). For another example, in the case where the execution of step S11 is skipped and the configuration shown in FIG. 4A / 4B is directly performed and then the configuration shown in FIG. 5A / 5B is performed, since the maximum output current of the reference voltage generating circuit 101 (or the reference voltage generator 102 or the reference voltage converter 103 therein) is very limited, there is still a problem of a long charging time. For another example, when skipping step S12 and first performing the configuration shown in FIG. 3A / 3B and then performing the configuration shown in FIG. 5A / 5B, when disabling the first dedicated current path corresponding to phase Phase1, there may be a significant configuration switching reaction time, which means that the target reference voltage VREF may continue to increase and significantly exceed the voltage level VA, so additional time is required for the target reference voltage VREF to reach the voltage level VA. Figure 7As shown, in the case of successively performing the configuration shown in FIG. 3A / 3B, the configuration shown in FIG. 4A / 4B and the configuration shown in FIG. 5A / 5B, the low dropout voltage regulator can immediately reach a stable state without any problem. For the sake of simplicity, similar contents in this embodiment are not repeated here.

[0047] For better understanding, this method can be used Figure 7 The workflow shown in FIG. 1 is used to illustrate the present invention, but the present invention is not limited thereto. According to some embodiments, one or more steps may be performed in Figure 7 The multi-stage configuration switching control circuit 110 can control other control signals such as control signals VREF_SHORT, VAUTO_FASTSET and VAUTO_FASTSET_B to change their states at the start time point of phase 2 according to the state transition of the control signal AF, so as to start the second configuration operation to set VREF=VR2. In addition, the automatic fast setting control circuit 120 can use the control signal AF to control the current control circuit 130, and in particular, control the current control circuit 130 to stop outputting the current I when VREF>VR2 is detected. For example, in the case where overheating does not occur, the current control circuit 130 can be implemented by a single transistor (e.g., MOSFET) or multiple transistors (e.g., multiple MOSFETs) coupled between the power line PWR and the switch circuit SW3 to act as a switch of the current I and selectively output the current I according to the control signal AF, wherein the switch circuit SW3 can be used to avoid any influence of the current control circuit 130 in steps S12 and S13. In addition, the operational amplifier 104 can be operated according to a biasing source BIAS (e.g., a current source or a voltage source). For the sake of simplicity, similar contents in these embodiments are not repeated here. The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention. [Description of Reference Numerals]

[0048] 100A,100B:Low Dropout (LDO) Regulator 101: Reference voltage generation circuit 102: Reference voltage generator 103: Reference Voltage Converter 104: Operational Amplifier (OPA) 106: Transistor 110: Multi-stage configuration switching control circuit 120: Automatic quick setting (AF) control circuit 130: Current control circuit BIAS: Bias source C1~C3: Capacitor MN1: N-type metal oxide semiconductor field effect transistor (MOSFET) MP1: P-type metal oxide semiconductor field effect transistor (MOSFET) PWR: power line R1, R2: resistors SW1~SW4: Switching circuit FASTSET: System control signal I: Current POW_LDO: power control signal VA,VB: voltage level VDD: power supply voltage VIP,VIN: Input voltage VOP,LDO_OUT: output voltage VR1, VR2: reference voltage VREF: target reference voltage VREF_SHORT,VAUTO_FASTSET,VAUTO_FASTSET_B,AF: control signal Phase 1~Phase 3: Phase3a, Phase3b: Sub-phases S11~S14: Steps

Claims

1. A low dropout voltage regulator, comprising: a reference voltage generating circuit, used to generate at least one reference voltage; an operational amplifier coupled to the reference voltage generating circuit, for controlling an output voltage of the low dropout regulator by negative feedback in a low dropout voltage regulation mode of the low dropout regulator; a transistor coupled to the operational amplifier, for generating the output voltage of the low dropout regulator under the control of the operational amplifier in the low dropout regulation mode for further use; and a multi-stage configuration switching control circuit coupled to the reference voltage generating circuit, the operational amplifier and the transistor for performing multi-stage configuration switching control to perform multiple configuration operations on the circuit architecture of the low dropout regulator; in: The multi-stage configuration switching control circuit performs a first configuration operation on the circuit architecture of the low dropout regulator to enable a first dedicated current path corresponding to a first stage, so as to allow a target reference voltage used in the low dropout regulation mode to reach a first predetermined range after performing the first configuration operation; The multi-stage configuration switching control circuit performs a second configuration operation on the circuit architecture of the low dropout regulator to enable a second dedicated current path corresponding to a second stage to allow the target reference voltage to reach a second predetermined range after performing the second configuration operation; as well as The multi-stage configuration switching control circuit performs a third configuration operation on the circuit architecture of the low dropout regulator to allow the target reference voltage to be used as a reference voltage input to the operational amplifier in the low dropout regulation mode after performing the third configuration operation.

2. The low dropout regulator of claim 1, wherein reaching the first predetermined range includes exceeding a second voltage level, and reaching the second predetermined range includes approaching a first voltage level, wherein the second voltage level is lower than the first voltage level. 3 . The low dropout regulator as claimed in claim 2 , wherein the at least one reference voltage comprises a first reference voltage equal to the first voltage level and a second reference voltage equal to the second voltage level.

4. The low dropout regulator of claim 1 , wherein performing the first configuration operation comprises: The first dedicated current path corresponding to the first stage is enabled to perform a first preliminary setting operation on the target reference voltage according to a power supply voltage, so as to accelerate the target reference voltage to reach the first predetermined range.

5. The low dropout regulator of claim 4, wherein reaching the first predetermined range includes exceeding a second voltage level, the at least one reference voltage includes a second reference voltage equal to the second voltage level; and performing the first configuration operation further comprises: coupling a plurality of input terminals of the operational amplifier to the target reference voltage and the second reference voltage respectively, so that the operational amplifier acts as a comparator for comparing the target reference voltage and the second reference voltage; The low dropout voltage regulator further comprises: an automatic fast setting control circuit coupled to an output terminal of the operational amplifier, for receiving a comparison result of the target reference voltage and the second reference voltage from the operational amplifier, and generating a control signal according to the comparison result; and A current control circuit is coupled to the automatic fast setting control circuit and is used for controlling the current on the first dedicated current path according to the control signal so as to accelerate the target reference voltage to reach the first predetermined range.

6. The low dropout regulator of claim 1 , wherein reaching the first predetermined range comprises exceeding a second voltage level, the at least one reference voltage comprises a second reference voltage equal to the second voltage level; and performing the first configuration operation comprises: A first input terminal and a second input terminal of the operational amplifier are coupled to the target reference voltage and the second reference voltage respectively, so that the operational amplifier acts as a comparator for comparing the target reference voltage and the second reference voltage.

7. The low dropout regulator of claim 6, wherein performing the first configuration operation further comprises: A negative feedback path between the second input terminal of the operational amplifier and a first terminal of the transistor is disconnected to disable the negative feedback path used in the low dropout regulation mode, wherein in the low dropout regulation mode, the first terminal of the transistor is used to output the output voltage of the low dropout regulator.

8. The low dropout regulator of claim 6, wherein performing the second configuration operation comprises: Stop coupling the second input terminal of the operational amplifier to the second reference voltage and couple the second input terminal of the operational amplifier to a first terminal of the transistor to enable a negative feedback path used in the low dropout voltage regulation mode, wherein in the low dropout voltage regulation mode, the first terminal of the transistor is used to output the output voltage of the low dropout regulator; deactivating the first dedicated current path corresponding to the first stage, wherein the first dedicated current path is coupled between a power line and the first input terminal of the operational amplifier in the first stage and is no longer coupled between the power line and the first input terminal of the operational amplifier in the second stage; and The second dedicated current path corresponding to the second stage is enabled to couple the first input terminal of the operational amplifier to the second reference voltage to force the target reference voltage to be equal to the second reference voltage, so as to reduce any deviation of the target reference voltage generated in the first stage relative to the second predetermined range to accelerate the target reference voltage to reach the second predetermined range.

9. The low dropout regulator of claim 8, wherein performing the third configuration operation comprises: The second dedicated current path corresponding to the second stage is disabled, wherein the second dedicated current path is no longer used to couple the first input terminal of the operational amplifier to the second reference voltage in a third stage.

10. An operating method, which can be applied to the low dropout voltage regulator according to claim 1, the operating method comprising: Performing the first configuration operation on the circuit architecture of the low dropout regulator using the multi-stage configuration switching control circuit to enable the first dedicated current path corresponding to the first stage, so as to allow the target reference voltage used in the low dropout regulation mode to reach the first predetermined range after performing the first configuration operation; Performing the second configuration operation on the circuit architecture of the low dropout regulator using the multi-stage configuration switching control circuit to enable the second dedicated current path corresponding to the second stage, so as to allow the target reference voltage to reach the second predetermined range after performing the second configuration operation; as well as The multi-stage configuration switching control circuit is used to perform the third configuration operation on the circuit architecture of the low dropout regulator to allow the target reference voltage to be used as the reference voltage input to the operational amplifier in the low dropout regulation mode after the third configuration operation.

Images