LDO control circuit, LDO control method and chip

Abstract

The invention discloses an LDO (Low Dropout Regulator) control circuit, an LDO control method and a chip, relates to the field of integrated circuit design, and solves the problems of low LDO efficiency and large output ripple of a charge pump circuit when power is supplied through the LDO or the charge pump circuit. The LDO control circuit comprises a power tube used for controlling connection and disconnection between a power supply and a load; the source following power tube is connected with power supply voltage and is connected with the power tube; the charge pump module is connected to two sides of the source following power tube in parallel; and the power supply voltage detection module is connected with the source following power tube and the charge pump module, and is used for detecting the magnitude of the power supply voltage and controlling the on-off of the charge pump module according to the power supply voltage and a preset voltage so as to provide load current for a load.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuit design, and in particular to a low dropout voltage regulator (Low Dropout Voltage Regulator, LDO) control circuit, an LDO control method and a chip. Background Art

[0002] At present, power consumption is one of the important indicators to measure the performance of electronic equipment. Low power consumption can extend the working time of electronic equipment and thus reduce energy consumption.

[0003] Both LDO and charge pump have the advantage of small on-chip integration area, and can be used to stabilize the high voltage voltage of the previous stage and output it to the subsequent electrical equipment. However, the efficiency of LDO circuit is low, especially when the input and output voltage difference is large. Although the charge pump circuit can achieve high efficiency, the output ripple is large. Summary of the invention

[0004] The present invention provides an LDO control circuit, an LDO control method and a chip, which solve the problems of low LDO efficiency and large output ripple of the charge pump circuit when power is supplied by the LDO or the charge pump circuit.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: In a first aspect, the present invention provides an LDO control circuit, which may include: Power tube, used to control the on-off between power supply and load; The source follows the power tube, which is connected to the power supply voltage and connected to the power tube; The charge pump module is connected in parallel on both sides of the source follower power tube; The power supply voltage detection module is connected to the source follower power tube and the charge pump module, and is used to detect the size of the power supply voltage and control the on and off of the charge pump module according to the power supply voltage and the preset voltage to provide load current to the load.

[0006] In a possible implementation, the power supply voltage detection module is specifically used to: When the power supply voltage is less than the preset voltage, the charge pump module is controlled to be turned off, and the source follower power tube provides load current to the load; When the power supply voltage is greater than the preset voltage, the charge pump module is controlled to be turned on, and the charge pump module and the source follower power tube jointly provide load current to the load.

[0007] In a possible implementation, the charge pump module includes N basic units, where N is a positive integer, and the N basic units are connected in series and parallel; The power supply voltage detection module is specifically used to determine the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value when the power supply voltage is greater than the preset voltage, and control K basic units to work to provide load current, where K is a positive integer less than or equal to N.

[0008] In a possible implementation, the power supply voltage detection module is specifically used to determine the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value when the power supply voltage is greater than the preset voltage, and control the K basic units connected in sequence including the highest level basic unit to work; Among them, the highest level basic unit is the basic unit that is closest to the power supply voltage.

[0009] In a possible implementation, the power supply voltage detection module is further configured to, when detecting that the power supply voltage is reduced, re-determine the number of working basic units according to the reduced power supply voltage; If the quantity is equal to K, it remains unchanged; If the number is less than K, start from the lowest level of the K basic units and reduce the number of working basic units from low to high.

[0010] In a possible implementation, the power supply voltage detection module is further configured to, when detecting that the power supply voltage has increased, re-determine the number of operating basic units according to the increased power supply voltage; If the quantity is equal to K, it remains unchanged; If the number is greater than K, start from the next level of basic units of K basic units and increase the number of working basic units from high to low.

[0011] In a second aspect, the present invention provides an LDO control method, which can be applied to the LDO control circuit of the first aspect and any possible implementation thereof. The LDO control method may include: Power tube, controls the on-off between power supply and load; The source follows the power tube, which is connected to the power supply voltage and connected to the power tube; The charge pump module is connected in parallel on both sides of the source follower power tube; The power supply voltage detection module is connected to the source follower power tube and the charge pump module to detect the power supply voltage and control the on and off of the charge pump module according to the power supply voltage and the preset voltage to provide load current to the load.

[0012] In a possible implementation, the power supply voltage detection module controls the on / off of the charge pump module according to the power supply voltage and the preset voltage to provide a load current to the load, which may specifically include: When the power supply voltage is less than the preset voltage, the power supply voltage detection module controls the charge pump module to shut down, and the source follower power tube provides load current to the load; When the power supply voltage is greater than the preset voltage, the power supply voltage detection module controls the charge pump module to be turned on, and the charge pump module and the source follower power tube jointly provide load current to the load.

[0013] In a possible implementation, the charge pump module includes N basic units, where N is a positive integer, and the N basic units are connected in series and parallel; When the power supply voltage is greater than a preset voltage, the power supply voltage detection module controls the charge pump module to be turned on, which may specifically include: When the power supply voltage is greater than the preset voltage, the power supply voltage detection module determines the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value, and controls K basic units to work to provide load current, where K is a positive integer less than or equal to N.

[0014] In a third aspect, the present invention provides a chip, which may include the LDO control circuit of the first aspect and any possible implementation thereof.

[0015] The LDO control circuit provided by the present invention connects charge pump modules in parallel on both sides of the source follower power tube as the parallel power supply of the LDO, and the power supply voltage detection module compares the power supply voltage with the preset voltage to control the on and off of the charge pump module to provide load current to the load. In this way, the LDO control circuit of the present invention can adaptively determine whether the charge pump module works according to the power supply voltage and load conditions, thereby simultaneously obtaining the advantages of the LDO circuit and the charge pump module power supply, that is, simultaneously obtaining high efficiency and low output ripple. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A circuit principle block diagram of an LDO control circuit provided by an embodiment of the present invention; Figure 2 A schematic diagram of a charge pump module provided by an embodiment of the present invention; Figure 3 A circuit schematic diagram of an LDO control circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "multiple" means two or more. In addition, the use of "based on" or "according to" means openness and inclusiveness, because the process, steps, calculations or other actions "based on" or "according to" one or more of the conditions or values ​​may be based on additional conditions or values ​​beyond the described values ​​in practice.

[0019] Figure 1 The circuit principle block diagram of a LDO control circuit provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the LDO control circuit may include: a power tube 11 , a source follower power tube 12 , a charge pump module 13 and a power supply voltage detection module 14 .

[0020] The power tube 11 is used to control the on-off between the power supply and the load. For example, the power tube 11 may be an NMOS tube.

[0021] The source follower power tube 12 is connected to the power supply voltage VCC and is connected to the power tube 11. For example, the source follower power tube 12 may be an NMOS tube.

[0022] The charge pump module 13 is connected in parallel to both sides of the source follower power tube 12 .

[0023] The power supply voltage detection module 14 is connected to the source follower power tube 12 and the charge pump module 13, and is used to detect the power supply voltage and control the on and off of the charge pump module 13 according to the power supply voltage and the preset voltage to provide load current to the load.

[0024] The LDO control circuit provided by the present invention connects charge pump modules in parallel on both sides of the source follower power tube as the parallel power supply of the LDO, and the power supply voltage detection module compares the power supply voltage with the preset voltage to control the on and off of the charge pump module to provide load current to the load. In this way, the LDO control circuit of the present invention can adaptively determine whether the charge pump module works according to the power supply voltage and load conditions, thereby simultaneously obtaining the advantages of the LDO circuit and the charge pump module power supply, that is, simultaneously obtaining high efficiency and low output ripple.

[0025] Optionally, in the embodiment of the present invention, the power supply voltage detection module 14 is specifically used for: When the power supply voltage is less than the preset voltage, the charge pump module 13 is controlled to be turned off, and at this time, the source follower power tube 12 provides the load current to the load.

[0026] When the power supply voltage is greater than the preset voltage, the charge pump module 13 is controlled to be turned on. At this time, the charge pump module 13 and the source follower power tube 12 jointly provide the load current to the load.

[0027] In this way, the power supply voltage detection module compares the power supply voltage with the preset voltage. If the power supply voltage is less than the preset voltage, it indicates that the power supply voltage is small. At this time, it is sufficient for the source follower power tube to provide the load current. If the power supply voltage is greater than the preset voltage, it indicates that the power supply voltage is large. At this time, the charge pump module is controlled to be turned on, so that the charge pump module acts as a parallel power supply of the LDO and provides load current at the same time, thereby improving the current efficiency of the LDO control circuit.

[0028] It should be noted that, in the embodiments of the present invention, the charge pump module has a different structure and occupies a different chip area. When the charge pump module and the source follower power tube jointly provide the load current, the charge pump module and the LDO respectively bear different proportions of the load current. Therefore, the design index of the charge pump module can be determined in advance according to the load conditions in the actual application scenario, so as to maximize the efficiency of the LDO control circuit while consuming a smaller chip area.

[0029] Optionally, in an embodiment of the present invention, Figure 2 FIG. 1 is a schematic diagram of a charge pump module 13 provided in an embodiment of the present invention. Figure 2 As shown, the charge pump module 13 may include N basic units, where N is a positive integer, and the N basic units are connected in series and parallel. Specifically, one end of the N basic units is connected to the power supply voltage, and the other end is grounded, and the N basic units are also connected to the source follower power tube 12 and the power supply voltage detection module 14.

[0030] The power supply voltage detection module is specifically used to query the correspondence between the pre-stored ratio and the number of basic units according to the ratio of the power supply voltage to the output voltage setting value when the power supply voltage is greater than the preset voltage, determine the number K of working basic units, and control K basic units to work to provide load current, where K is a positive integer less than or equal to N.

[0031] When the power supply voltage is greater than the preset voltage, the power supply voltage detection module determines K basic units to be operated from N basic units according to the ratio of the power supply voltage to the output voltage setting value. In this way, the advantages of simultaneously obtaining power supply from the LDO circuit and the charge pump module can be obtained within a wide load range, that is, high efficiency and low output ripple can be obtained at the same time.

[0032] Furthermore, in an embodiment of the present invention, the power supply voltage detection module is specifically used to determine the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value when the power supply voltage is greater than a preset voltage, and control the operation of K basic units connected in sequence including the highest-level basic unit.

[0033] The highest level basic unit is the basic unit that is closest to the power supply voltage. Figure 2 Assuming that N is 4 and the number K of working basic units is determined to be 2, the power supply voltage detection module 14 can control the highest level basic unit closest to the power supply voltage and the next level basic unit to work to provide load current.

[0034] Optionally, in the embodiment of the present invention, the power supply voltage detection module 14 is further used to re-determine the number of working basic units according to the reduced power supply voltage when detecting that the power supply voltage is reduced. If the number is equal to K, it remains unchanged; if the number is less than K, the number of working basic units is reduced from the lowest level among the K basic units from low to high.

[0035] Optionally, in the embodiment of the present invention, the power supply voltage detection module 14 is further used to re-determine the number of working basic units according to the increased power supply voltage when detecting that the power supply voltage increases. If the number is equal to K, it remains unchanged; if the number is greater than K, the number of working basic units is increased from high to low starting from the next level basic unit of the K basic units.

[0036] In this way, the power supply voltage detection module can detect the magnitude of the power supply voltage in real time, and adjust the number of working basic units in the charge pump module in real time, thereby further improving the efficiency of the LDO control circuit.

[0037] Exemplarily, in an embodiment of the present invention, Figure 3 The schematic diagram of a LDO control circuit provided by an embodiment of the present invention is shown in FIG. Figure 3 As shown, the LDO control circuit may include: an NMOS power tube M0, an NMOS source follower power tube M1, a charge pump module 13, a power supply voltage detection module 14, an operational amplifier I0, a resistor R0, a resistor R1, and a capacitor C0.

[0038] The operational amplifier I0, the feedback resistors R0 and R1, the power tube M0, and the source follower power tube M1 can form a high voltage LDO circuit. Of course, the LDO control circuit of the embodiment of the present invention can also be applied to low voltage scenarios.

[0039] The positive input terminal of the operational amplifier I0 is connected to the reference voltage VREF, and the negative input terminal is connected to the feedback voltage VFB. The operational amplifier I0 adjusts the gate voltage of the power tube M0 according to the difference between VREF and VFB so that the output voltage is the output voltage setting value.

[0040] Capacitor C0 is the output capacitor of the LDO control circuit and is used to stabilize the output voltage.

[0041] In high-voltage scenarios, the source follower power tube M1 can block the high-voltage power supply, so that both the op amp I0 and the power tube M0 can be implemented using low-voltage devices. At the same time, M1 provides convenience for the parallel charge pump module 13.

[0042] The embodiment of the present invention also provides an LDO control method, which can be applied to the above Figure 1-Figure 3 The LDO control circuit in. The LDO control method may include: Power tube, controls the on-off between power supply and load; The source follows the power tube, which is connected to the power supply voltage and connected to the power tube; The charge pump module is connected in parallel on both sides of the source follower power tube; The power supply voltage detection module is connected to the source follower power tube and the charge pump module to detect the power supply voltage and control the on and off of the charge pump module according to the power supply voltage and the preset voltage to provide load current to the load.

[0043] In this way, by connecting the charge pump module in parallel on both sides of the source follower power tube as the parallel power supply of the LDO, the power supply voltage detection module compares the power supply voltage with the preset voltage to control the on and off of the charge pump module to provide the load current to the load. The LDO control circuit of the present invention can adapt to the power supply voltage and load conditions to determine whether the charge pump module works, thereby simultaneously obtaining the advantages of the LDO circuit and the charge pump module power supply, that is, simultaneously obtaining high efficiency and low output ripple.

[0044] Optionally, in an embodiment of the present invention, the power supply voltage detection module controls the on / off of the charge pump module according to the power supply voltage and the preset voltage to provide a load current to the load, which may specifically include: When the power supply voltage is less than the preset voltage, the power supply voltage detection module controls the charge pump module to turn off, and the source follower power tube provides load current to the load.

[0045] When the power supply voltage is greater than the preset voltage, the power supply voltage detection module controls the charge pump module to be turned on, and the charge pump module and the source follower power tube jointly provide load current to the load.

[0046] In this way, the power supply voltage detection module compares the power supply voltage with the preset voltage. If the power supply voltage is less than the preset voltage, it indicates that the power supply voltage is small. At this time, it is sufficient for the source follower power tube to provide the load current. If the power supply voltage is greater than the preset voltage, it indicates that the power supply voltage is large. At this time, the charge pump module is controlled to be turned on, so that the charge pump module acts as a parallel power supply of the LDO and provides load current at the same time, thereby improving the current efficiency of the LDO control circuit.

[0047] Optionally, in an embodiment of the present invention, the charge pump module includes N basic units, N is a positive integer, and the N basic units are connected in series and parallel. When the power supply voltage is greater than the preset voltage, the power supply voltage detection module controls the charge pump module to be turned on, which may specifically include: When the power supply voltage is greater than the preset voltage, the power supply voltage detection module determines the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value, and controls K basic units to work to provide load current, where K is a positive integer less than or equal to N.

[0048] Optionally, in the embodiment of the present invention, when the power supply voltage is greater than the preset voltage, the power supply voltage detection module determines the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value, and controls the K basic units to work, which may specifically include: When the power supply voltage is greater than the preset voltage, the power supply voltage detection module determines the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value, and controls the K basic units connected in sequence including the highest level basic unit to work.

[0049] The embodiment of the present invention further provides a chip, which may include Figure 1-Figure 3 Any LDO control circuit in.

[0050] In a possible implementation, the chip may be a power management chip, and of course, may also be other types of chips, which are not specifically limited here.

[0051] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An LDO control circuit, characterized in that: include: Power tube, used to control the on-off between power supply and load; A source follower power tube is connected to the power supply voltage and is connected to the power tube; A charge pump module is connected in parallel on both sides of the source follower power tube; The power supply voltage detection module is connected to the source follower power tube and the charge pump module, and is used to detect the magnitude of the power supply voltage and control the on and off of the charge pump module according to the power supply voltage and a preset voltage to provide a load current to the load.

2. The LDO control circuit according to claim 1, characterized in that: The power supply voltage detection module is specifically used for: When the power supply voltage is less than the preset voltage, the charge pump module is controlled to be turned off, and the source follower power tube provides a load current to the load; When the power supply voltage is greater than the preset voltage, the charge pump module is controlled to be turned on, and the charge pump module and the source follower power tube jointly provide a load current to the load.

3. The LDO control circuit according to claim 2, characterized in that: The charge pump module comprises N basic units, N is a positive integer, and the N basic units are connected in series and parallel; The power supply voltage detection module is specifically used to determine the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value when the power supply voltage is greater than the preset voltage, and control K basic units to work to provide load current, where K is a positive integer less than or equal to N.

4. The LDO control circuit according to claim 3, characterized in that: The power supply voltage detection module is specifically used to determine the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value when the power supply voltage is greater than the preset voltage, and control the K basic units connected in sequence including the highest level basic unit to work; The highest level basic unit is the basic unit that is closest to the power supply voltage.

5. The LDO control circuit according to claim 4, characterized in that: The power supply voltage detection module is further used to re-determine the number of working basic units according to the reduced power supply voltage when detecting that the power supply voltage is reduced; If the said quantity is equal to K, it remains unchanged; If the number is less than K, then starting from the lowest level among the K basic units, the number of working basic units is reduced from low to high.

6. The LDO control circuit according to claim 4, characterized in that: The power supply voltage detection module is further used to re-determine the number of working basic units according to the increased power supply voltage when detecting that the power supply voltage increases; If the said quantity is equal to K, it remains unchanged; If the number is greater than K, the number of working basic units is increased from high to low, starting from the next level basic unit of the K basic units.

7. A LDO control method, characterized in that: The LDO control circuit as claimed in any one of claims 1 to 6 comprises: Power tube, controls the on-off between power supply and load; A source follower power tube is connected to the power supply voltage and is connected to the power tube; A charge pump module is connected in parallel on both sides of the source follower power tube; The power supply voltage detection module is connected to the source follower power tube and the charge pump module, detects the magnitude of the power supply voltage, and controls the on and off of the charge pump module according to the power supply voltage and a preset voltage to provide a load current to the load.

8. The LDO control method according to claim 7, characterized in that: The power supply voltage detection module controls the on / off of the charge pump module according to the power supply voltage and the preset voltage to provide a load current to the load, including: When the power supply voltage is less than the preset voltage, the power supply voltage detection module controls the charge pump module to be turned off, and the source follower power tube provides a load current to the load; When the power supply voltage is greater than the preset voltage, the power supply voltage detection module controls the charge pump module to be turned on, and the charge pump module and the source follower power tube jointly provide a load current to the load.

9. The LDO control method according to claim 8, characterized in that: The charge pump module comprises N basic units, N is a positive integer, and the N basic units are connected in series and parallel; When the power supply voltage is greater than the preset voltage, the power supply voltage detection module controls the charge pump module to be turned on, including: When the power supply voltage is greater than the preset voltage, the power supply voltage detection module determines the number K of working basic units according to the ratio of the power supply voltage to the output voltage setting value, and controls K basic units to work to provide load current, where K is a positive integer less than or equal to N.

10. A chip, characterized in that: The chip includes the LDO control circuit according to any one of claims 1 to 6.

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