Power control circuit, chip, low dropout linear regulator and device

Abstract

This application provides a power control circuit, chip, low-dropout linear regulator, and device, comprising: a voltage detector and a current feedback unit. The voltage detector transmits a first current to the current feedback unit when the voltage difference between the input voltage and the output voltage exceeds a threshold voltage. The input voltage is the voltage received at the input terminal of the low-dropout linear regulator, and the output voltage is the voltage supplied to the output terminal of the low-dropout linear regulator. Based on the first current, the current feedback unit controls the output current of the image transistor to decrease, thereby controlling the output current of the power transistor in the low-dropout linear regulator to decrease, ensuring that the power of the power transistor is less than or equal to the threshold power. This prevents the power of the power transistor from increasing linearly with the increase of the voltage difference between the input and output voltages, thus preventing damage to the power transistor.

Description

Technical Field

[0001] This application relates to the field of low dropout linear regulator technology, and in particular to a power control circuit, chip, low dropout linear regulator and device. Background Technology

[0002] Low dropout regulators (LDOs) have a current limiting protection function, which allows the LDO to output a constant output current when the output voltage is lower than a preset threshold.

[0003] In traditional technology, the low-dropout linear regulator of an LDO is like... Figure 1 As shown, a low-dropout linear regulator (LDO) includes a power transistor. The power of the power transistor increases linearly with the voltage difference between the LDO's input and output voltages. Because the power of the power transistor increases linearly, its temperature rises, potentially leading to damage.

[0004] Therefore, how to design a low-dropout linear regulator to avoid the power of the power transistor increasing linearly with the voltage difference between the LDO's input voltage and output voltage, and to prevent damage to the power transistor, has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a power control circuit, chip, low dropout linear regulator, and device to solve the problem that the power of the power transistor increases linearly with the increase of the voltage difference between the input voltage and the output voltage of the LDO, leading to damage to the power transistor.

[0006] In a first aspect, this application provides a power control circuit applied to a low-dropout linear regulator. The power control circuit includes a voltage detector and a current feedback unit. The first input terminal of the voltage detector is electrically connected to the input terminal of the low-dropout linear regulator, the second input terminal of the voltage detector is electrically connected to the output terminal of the low-dropout linear regulator, the output terminal of the voltage detector is electrically connected to the input terminal of the current feedback unit, the second terminal of the current feedback unit is electrically connected to the first input terminal of a first amplifier in the low-dropout linear regulator, and the third terminal of the current feedback unit is electrically connected between a transistor imager and a second voltage feedback module in the low-dropout linear regulator. The input terminal of the low-dropout linear regulator is used to receive the input voltage, and the output terminal of the low-dropout linear regulator is used to provide the output voltage.

[0007] A voltage detector is used to transmit a first current to the current feedback unit when the voltage difference between the input voltage and the output voltage is greater than a threshold voltage.

[0008] A current feedback circuit is used to control the output current of the mirror transistor to decrease based on a first current, thereby controlling the output current of the power transistor in the low dropout linear regulator to decrease, so that the power of the power transistor is less than or equal to the threshold power.

[0009] With the power control circuit provided in the first aspect, when the voltage difference between the input voltage and the output voltage is greater than the voltage threshold, the voltage detector transmits a first current to the current feedback unit. Based on the first current, the current feedback unit controls the output current of the mirror transistor to decrease, thereby controlling the output current of the power transistor to decrease, so that the power of the power transistor is less than or equal to the threshold power. That is, when the voltage difference between the input voltage and the output voltage increases, the power of the power transistor is less than or equal to the threshold power, avoiding the power of the power transistor from increasing linearly with the increase of the voltage difference between the input voltage and the output voltage, thereby avoiding the temperature rise of the power transistor and preventing damage to the power transistor.

[0010] In one possible design, the voltage detector includes a second resistor, a third resistor, and a second transistor. The first terminal of the second resistor is electrically connected between the input terminal of the low-dropout linear regulator and the first terminal of the power transistor. The second terminal of the second resistor is electrically connected to the first terminal of the second transistor. The control terminal of the second transistor is electrically connected to the output terminal of the low-dropout linear regulator. The second terminal of the second transistor is electrically connected to the first terminal of the third resistor, and the second terminal of the third resistor is grounded.

[0011] In one possible design, the current feedback circuit includes a first diode and a fourth resistor. The first terminal of the first diode is electrically connected to the third terminal of the voltage detector, the second terminal of the first diode is electrically connected to the first input terminal of the first amplifier, the first terminal of the fourth resistor is electrically connected between the second terminal of the first diode and the first input terminal of the first amplifier, and the second terminal of the fourth resistor is electrically connected between the image sensor and the second voltage feedback module.

[0012] In one possible design, the formula for calculating the threshold voltage is:

[0013] Where VMIN represents the threshold voltage, VREF2 represents the first reference voltage received at the second input terminal of the first amplifier, V_D2 represents the voltage of the first diode, R3 represents the resistance value of the second resistor, and R4 represents the resistance value of the third resistor.

[0014] In one possible design, the formula for calculating the output current of the power transistor is:

[0015]

[0016] The formula for calculating the power of a power transistor is:

[0017] P = (VIN - VOUT) * IOUT = (VIN - VOUT) * A0 * (A1 - (VIN - VOUT)), where IOUT represents...

[0018] Indicates the output current of the power transistor ， K represents the ratio of the power transistor's output current to the image transistor's output current, and R5 represents the resistance value of the fourth resistor. S VIN represents the resistance value of the second voltage feedback module, A0 represents the first intermediate value, A1 represents the second intermediate value, VOUT represents the output voltage, and P represents the power of the power transistor.

[0019] In one possible design, the formula for calculating the threshold power is: Among them, P 阈 This represents the threshold power.

[0020] Secondly, this application provides a method for implementing a power control circuit, applied to the power control circuit of any one of the first aspects. The method includes: when a voltage detector detects that the voltage difference between the input voltage and the output voltage is greater than a threshold voltage, transmitting a first current to a current feedback unit. Based on the first current, the current feedback unit controls the output current of the image transistor to decrease, thereby controlling the output current of the power transistor to decrease, so that the power of the power transistor is less than or equal to a threshold power.

[0021] The beneficial effects of the power control circuit implementation method provided in the second aspect of the design can be found in the beneficial effects of the first aspect, and will not be repeated here.

[0022] Thirdly, this application provides a low dropout linear regulator, comprising: an input terminal, an output terminal, a power transistor, a mirror transistor, a first voltage feedback module, a second voltage feedback module, a first amplifier, a second amplifier, a second diode, and a power control circuit according to any one of the first aspects.

[0023] The power transistor and the first voltage feedback module are connected in series between the input terminal and the ground terminal.

[0024] The image transistor and the power transistor form a current mirror structure, and the image transistor and the second voltage feedback module are connected in series between the input terminal and the ground terminal.

[0025] The first input terminal of the first amplifier is electrically connected to the second terminal of the current feedback in the power control circuit. The second input terminal is used to receive the first reference voltage. The output terminal is electrically connected to the positive terminal of the second diode. The negative terminal of the second diode is electrically connected to the control terminal of the power transistor.

[0026] The first input terminal of the second amplifier is coupled to the first voltage feedback module, the second input terminal is used to receive the second reference voltage, and the output terminal is electrically connected to the control terminal of the power transistor.

[0027] The beneficial effects of the low-dropout linear regulator provided in the third aspect of the design can be seen in the beneficial effects brought about by the first aspect, and will not be repeated here.

[0028] Fourthly, this application provides a chip, comprising: a power control circuit according to any one of the first aspects, or a low dropout linear regulator according to the third aspect.

[0029] The beneficial effects of the chip provided in the fourth aspect of the design can be seen in the beneficial effects brought about by the first and third aspects mentioned above, and will not be repeated here.

[0030] Fifthly, this application provides an electronic device, including: the chip of the fourth aspect.

[0031] The beneficial effects of the electronic device provided in the design of the fifth aspect above can be seen from the beneficial effects brought about by the fourth aspect above, and will not be repeated here. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a low-dropout linear regulator provided in traditional technology;

[0033] Figure 2 This is a schematic diagram of the low-dropout linear regulator provided in the embodiments of this application;

[0034] Figure 3 This is a schematic diagram of the power control circuit provided in an embodiment of this application;

[0035] Figure 4 This is a schematic flowchart of the implementation method of the power control circuit provided in the embodiments of this application;

[0036] Figure 5 This is a schematic diagram of the power control circuit provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of the power control circuit provided in the embodiment of this application. Detailed Implementation

[0038] In this application, "at least one" means one or more, and "multiple" means two or more. "And / or" describes the relationship between associated objects and indicates that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or its similar expressions refer to any combination of these items, including any combination of single item(s) or plural item(s). For example, at least one of a alone, b alone, or c alone can mean: a alone, b alone, c alone, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b, and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0039] The orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on this application.

[0040] The terms "connected" and "coupled" should be understood in a broad sense. For example, the "connection" or "coupling" of a circuit structure can refer not only to a physical connection but also to an electrical connection or a signal connection. For example, it can be a direct connection, i.e., a physical connection, or it can be indirectly connected through at least one intermediate element, as long as the circuit is connected. It can also be the connection inside two elements. A signal connection can refer not only to a signal connection through a circuit but also to a signal connection through a media medium, such as radio waves. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] Figure 1 is a schematic structural diagram of a low dropout linear regulator provided in the prior art. As Figure 1 shown, the low dropout linear regulator includes: an input terminal, a power transistor M1, a mirror transistor MS, a first amplifier A2, a second amplifier A1, a first resistor RS, a fifth resistor R1, a sixth resistor R2, a second diode D1, a first capacitor C1, and an output terminal.

[0042] The input terminal is used to receive an input voltage VIN, and the output terminal is used to provide an output voltage VOUT.

[0043] The first terminal of power transistor M1 and the first terminal of mirror transistor MS are both electrically connected to the input terminal. The control terminal of power transistor M1 and the control terminal of mirror transistor MS are both electrically connected to the output terminal of second amplifier A1 and the cathode of second diode D1. The second terminal of power transistor M1 is electrically connected to the first terminal of fifth resistor R1. The second terminal of fifth resistor R1 is electrically connected to the first terminal of sixth resistor R2. The second terminal of sixth resistor R2 is grounded. The second terminal of mirror transistor MS is electrically connected to the first terminal of first resistor RS. The second terminal of first resistor RS is grounded. The second input terminal of first amplifier A2 is used to receive the first reference voltage VREF2. The first input terminal is electrically connected between the second terminal of the mirror transistor MS and the first terminal of the first resistor RS. The output terminal of the first amplifier A2 is electrically connected to the anode of the second diode D1. The second input terminal of the second amplifier A1 is used to receive the second reference voltage VREF1. The first input terminal of the second amplifier A1 is electrically connected between the second terminal of the fifth resistor R1 and the first terminal of the sixth resistor R2. The output terminal is electrically connected between the second terminal of the power transistor M1 and the first terminal of the fifth resistor R1. The first terminal of the first capacitor C1 and the first terminal of the load are both electrically connected between the output terminal and the second terminal of the power transistor M1. The second terminal of the first capacitor C1 is grounded, and the second terminal of the load is grounded.

[0044] The power transistor M1 is the transmission transistor of the LDO.

[0045] The mirror transistor MS is used to mirror the current of the power transistor M1.

[0046] The ratio of the output current IOUT of power transistor M1 (i.e., the output current of the LDO) to the output current IS of the mirror transistor MS is K, that is:

[0047]

[0048] When IOUT increases to the threshold current (i.e., the current limit), the output current IS passes through the first resistor RS, generating a voltage VS. The formula for calculating the voltage VS is:

[0049] VS = IOUT * R S (2)

[0050] Among them, R S This indicates the resistance value of the first resistor, RS.

[0051] The difference between voltage VS and the first reference voltage VREF2 is amplified by the first amplifier A2. When voltage VS is greater than the first reference voltage VREF2, the output voltage V2 of the first amplifier A2 increases, and through the second diode D1, it pulls up the voltage VG between the gate of power transistor M1 and the gate of mirror transistor M2, thereby reducing the voltage VGS between the gate and source of power transistor M1, and consequently reducing the output current IOUT of power transistor M1 and the output current IS of mirror transistor M2. The mirror transistor MS, the first resistor RS, the first amplifier A2, and the second diode D1 form a negative feedback loop, which ultimately stabilizes voltage VS at the first reference voltage VREF2.

[0052] VS = VREF2 (3)

[0053] From formulas (1), (2) and (3), the current limit value of IOUT can be obtained as follows:

[0054]

[0055] Since the voltage difference across power transistor M1 is equal to (VIN - VOUT), and the current flowing through power transistor M1 is equal to IOUT, the power P of power transistor M1 is:

[0056]

[0057] As can be seen from formula (5), the power P of power transistor M1 is linearly related to (VIN-VOUT), that is, the power P of power transistor M1 increases linearly with the increase of the voltage difference between input voltage VIN and output voltage VOUT.

[0058] Optionally, the voltage difference between the input voltage VIN and the output voltage VOUT increases when the input voltage VIN increases and / or the output voltage VOUT decreases.

[0059] In traditional technology, the power P of power transistor M1 increases linearly with the increase of the voltage difference between input voltage VIN and output voltage VOUT, which will cause the temperature of power transistor M1 to rise, and thus damage power transistor M1.

[0060] To address the aforementioned technical problems, this application provides a power control circuit that can be applied to the low-dropout linear regulator provided in this application.

[0061] Figure 2 This is a schematic diagram of the low-dropout linear regulator provided in an embodiment of this application. Figure 2As shown, the low dropout linear regulator includes: an input terminal, an output terminal, a power transistor M1, a mirror transistor MS, a first voltage feedback module 1, a second voltage feedback module 2, a first amplifier A2, a second amplifier A1, a second diode D1, and a power control circuit provided in the embodiments of this application.

[0062] The power transistor M1 is connected in series with the first voltage feedback module 1 between the input terminal and the ground terminal.

[0063] The mirror transistor MS and the power transistor M1 form a current mirror structure, and the mirror transistor and the second voltage feedback module 2 are connected in series between the input terminal and the ground terminal.

[0064] The first input terminal of the first amplifier A2 is electrically connected to the second terminal of the current feedback unit 002 in the power control circuit. The second input terminal is used to receive the first reference voltage VREF2. The output terminal is electrically connected to the positive terminal of the second diode D1. The negative terminal of the second diode D1 is electrically connected to the control terminal of the power transistor M1.

[0065] The first input terminal of the second amplifier A1 is coupled to the first voltage feedback module 1, the second input terminal is used to receive the second reference voltage VREF1, and the output terminal is electrically connected to the control terminal of the power transistor M1.

[0066] Optionally, the first voltage feedback module 1 includes a fifth resistor R1 and a sixth resistor R2.

[0067] Optionally, the second voltage feedback module 2 includes: a first resistor RS.

[0068] The low-dropout linear regulator 0.01 may also include a first capacitor C1. The electrical connections of the fifth resistor R1, the sixth resistor R2, the first resistor RS, and the first capacitor C1 in the low-dropout linear regulator are as follows: Figure 2 As shown, it will not be elaborated further here.

[0069] Figure 3 This is a schematic diagram of the power control circuit provided in an embodiment of this application. Figure 3 As shown, the power control circuit includes a voltage detector 001 and a current feedback unit 002.

[0070] The first input terminal of the voltage detector 001 is electrically connected to the input terminal of the low dropout linear regulator. The second input terminal of the voltage detector 001 is electrically connected to the output terminal of the low dropout linear regulator. The output terminal of the voltage detector 001 is electrically connected to the input terminal of the current feedback unit 002. The second terminal of the current feedback unit 002 is electrically connected to the first input terminal of the first amplifier A2 in the low dropout linear regulator. The third terminal of the current feedback unit 002 is electrically connected between the mirror transistor MS and the second voltage feedback module 2 in the low dropout linear regulator.

[0071] In the case where the second voltage feedback module 2 includes the first resistor RS, the third terminal of the current feedback unit 002 is electrically connected between the mirror tube MS and the first resistor RS.

[0072] The input terminal of the low-dropout linear regulator is used to receive the input voltage VIN, and the output terminal of the low-dropout linear regulator is used to provide the output voltage VOUT.

[0073] Voltage detector 001 is used to detect the voltage difference between the input voltage VIN and the output voltage VOUT.

[0074] Current feedback unit 002 is used to control the output current IS of the mirror transistor MS to decrease.

[0075] The voltage detector 001 and the current feedback unit 002 can be integrated or set up separately, depending on the actual needs.

[0076] Based on the electrical connection relationship between the low-dropout linear regulator, voltage detector 001, and current feedback unit 002, the low-dropout linear regulator has the following characteristics: Figure 4 The implementation method shown.

[0077] Figure 4 This is a schematic flowchart illustrating the implementation method of the power control circuit provided in this application embodiment. Figure 4 As shown, the implementation method includes:

[0078] S401, when the voltage detector 001 detects that the voltage difference between the input voltage VIN and the output voltage VOUT is greater than the voltage threshold, it transmits a first current to the current feedback unit 002.

[0079] The voltage threshold is determined by the voltage detector 001 and the current feedback unit 002.

[0080] The first current is used to indicate that the voltage difference between the input voltage VIN and the output voltage VOUT is greater than the voltage threshold.

[0081] S402 and current feedback 002 control the output current IS of the mirror transistor MS to decrease according to the first current, so as to control the output current IOUT of the power transistor M1 to decrease, so that the power of the power transistor M1 is less than or equal to the threshold power.

[0082] The output current IS is the mirror current of the output current IOUT.

[0083] The output current IOUT decreases as the output current IS decreases.

[0084] The threshold power is determined based on the voltage difference between the input voltage VIN and the output voltage VOUT, the voltage detector 001, and the current feedback unit 002.

[0085] In this embodiment, when the voltage difference between the input voltage VIN and the output voltage VOUT is greater than a voltage threshold, the voltage detector 001 transmits a first current to the current feedback unit 002. Based on the first current, the current feedback unit 002 controls the output current IS of the mirror transistor MS to decrease, thereby controlling the output current IOUT of the power transistor M1 to decrease, so that the power of the power transistor M1 is less than or equal to the threshold power. That is, when the voltage difference between the input voltage VIN and the output voltage VOUT increases, the power of the power transistor M1 is less than or equal to the threshold power, avoiding the power P of the power transistor M1 from increasing linearly with the increase of the voltage difference between the input voltage VIN and the output voltage VOUT, thereby avoiding the temperature rise of the power transistor M1 and preventing damage to the power transistor.

[0086] Figure 5 This is a schematic diagram of the power control circuit provided in an embodiment of this application. For example, in Figure 3 On the basis of, such as Figure 5 As shown, the voltage detector 001 includes: a second resistor R3, a third resistor R4, and a second transistor M2.

[0087] The first end of the second resistor R3 is electrically connected between the input terminal of the low dropout linear regulator and the first end of the power transistor M1. The second end of the second resistor R3 is electrically connected to the first end of the second transistor M2. The control terminal of the second transistor M2 is electrically connected to the output terminal of the low dropout linear regulator. The second end of the second transistor M2 is electrically connected to the first end of the third resistor R4. The second end of the third resistor R4 is grounded.

[0088] The second transistor M2 can be, for example, a P-type metal oxide semiconductor (PMOS).

[0089] The second resistor R3, the third resistor R4, and the second transistor M2 can be integrated or separated, depending on the actual requirements.

[0090] Figure 6 This is a schematic diagram of the power control circuit provided in an embodiment of this application. For example, in Figure 5 On the basis of, such as Figure 6 As shown, the current feedback device 002 includes: a first diode D2 and a fourth resistor R5.

[0091] The first terminal of the first diode D2 is electrically connected to the third terminal of the voltage detector 001, the second terminal of the first diode D2 is electrically connected to the first input terminal of the first amplifier A2, the first terminal of the fourth resistor R5 is electrically connected between the second terminal of the first diode D2 and the first input terminal of the first amplifier A2, and the second terminal of the fourth resistor R5 is electrically connected between the mirror transistor MS and the second voltage feedback module 2.

[0092] Specifically, the second end of the fourth resistor R5 is electrically connected between the second end of the mirror transistor MS and the first end of the first resistor RS in the second voltage feedback module 2.

[0093] The first diode D2 and the fourth resistor R5 can be integrated or separated.

[0094] In one possible design, the voltage threshold VMIN is calculated using the following formula:

[0095]

[0096] Where VMIN represents the voltage threshold, VREF2 represents the first reference voltage received at the second input terminal of the first amplifier A2, V_D2 represents the voltage of the first diode D2, R4 represents the resistance value of the third resistor R4, and R3 represents the resistance value of the second resistor R3.

[0097] In one possible design, the formula for calculating the output current IOUT of power transistor M1 is:

[0098]

[0099] The formula for calculating the power of power transistor M1 is:

[0100] P=(VIN-VOUT)*IOUT=(VIN-VOUT)*A0*(A1-(VIN-VOUT)) (8)

[0101] Where IOUT represents the output current of power transistor M1, K represents the ratio of the output current IS of power transistor M1 to the output current IOUT of the mirror transistor MS, R5 represents the resistance value of the fourth resistor R5, R SVIN represents the resistance value of the second voltage feedback module 2 (which is equal to the resistance value of the first resistor RS), A0 represents the first intermediate value, A1 represents the second intermediate value, VOUT represents the output voltage, and P represents the power of the power transistor M1.

[0102] The reasoning process for obtaining formulas (6), (7), and (8) will be explained below.

[0103] exist Figure 6 Based on this, the formula for calculating the current I3 of the second resistor R3 is:

[0104]

[0105] Wherein, VGS_M2 represents the gate and source voltages of the second transistor M2.

[0106] When the voltage difference between the input voltage VIN and the output voltage VOUT is large, VGS_M2 can be ignored. Therefore, the current I3 across the second resistor R3 is:

[0107]

[0108] When the low-dropout linear regulator is in current-limited mode (i.e., the output voltage is below the preset threshold), the second amplifier A2 is in normal amplification mode. According to the virtual short principle of amplifiers, voltage VS2 and the first reference voltage VREF2 are equal, that is:

[0109] VS2 = VREF2 (11)

[0110] Since the forward voltage of the first diode D2 changes little with the current flowing through it, V_D2 can be considered a fixed value. Therefore, the formula for calculating voltage VS3 is:

[0111] VS3=VS2+V_D2=VREF2+V_D2 (12)

[0112] When the low-dropout linear regulator is in current-limited state, the voltage VS3 is constant, a portion of the current I3 flows through the third resistor R4, and another portion of the current I3 flows through the first diode D2.

[0113] When the voltage difference between VIN and VOUT increases, the current I3 increases. Since the voltage VS3 remains approximately constant, the current flowing through the third resistor R4 remains constant, resulting in an increase in the current flowing through the fourth resistor R5. Furthermore, since the voltage VS2 remains constant, the voltage VS1 decreases.

[0114] The voltage VS1 is generated by the output current IS flowing through the first resistor RS. Therefore, when the voltage VS1 decreases, the output current IS decreases. Since the output current IS and the output current IOUT are proportional, when the current IS decreases, the output current IOUT also decreases. That is, when the voltage difference between VIN and VOUT increases, the current I3 increases, the output current IS decreases, and consequently, the output current IOUT decreases.

[0115] When the low-dropout linear regulator is in current-limited state, according to formula (12), the voltage VS3 remains constant and is equal to the voltage across the third resistor R4. Before another portion of the current I3 flows to the critical state of the first diode D2, all of the current I3 flows to the third resistor R4, thus generating the voltage VS3. Therefore, the purpose of setting VMIN can be achieved by adjusting the resistance value of the third resistor R4, that is:

[0116]

[0117] Combining formulas (12) and (13), we get:

[0118] When the voltage difference between VIN and VOUT is greater than VMIN, another portion of the current I3 (i.e., the first current) begins to flow to the first diode D2 (i.e., the voltage detector 001 transmits the first current to the current feedback device). The formula for calculating the first current is:

[0119]

[0120] The first current flows to the fourth resistor R5, therefore the formula for calculating voltage VS1 is:

[0121] VS1 = VS2 - I D2 *R5 (15)

[0122] According to formulas (1), (2), (11), (14) and (15), the output current I can be obtained. oUT for:

[0123]

[0124] To simplify the explanation, formula (16) can also be simplified to:

[0125]

[0126] The formula for calculating the power of power transistor M1 is:

[0127] P = (VIN - VOUT) * IOUT (17)

[0128] Combining formula (7) and formula (17), we can obtain formula (8).

[0129] It can be seen from formula (8) that when (V IN -V OUT When I increases, OUT =A0*[A1-(V IN -V OUT The value of ] will decrease, thus causing the power of power transistor M1 to be less than or equal to the threshold power.

[0130] In one possible design, the threshold power P 阈 The calculation formula is:

[0131]

[0132] This application also provides a chip, including: Figure 2 The low dropout linear regulator shown and Figures 3 to 6 The power control circuit shown in any embodiment.

[0133] The chip provided in this application embodiment has the same beneficial effects as the low dropout linear regulator and power control circuit provided in this application, and will not be described again here.

[0134] This application also provides an electronic device, including the aforementioned chip.

[0135] The electronic device has the same beneficial effects as the chip provided in this application, and will not be described in detail here.

[0136] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power control circuit, characterized in that, The power control circuit, applied to low dropout linear regulators, includes a voltage detector and a current feedback unit. The first input terminal of the voltage detector is electrically connected to the input terminal of the low-dropout linear regulator, the second input terminal of the voltage detector is electrically connected to the output terminal of the low-dropout linear regulator, the output terminal of the voltage detector is electrically connected to the input terminal of the current feedback unit, the second terminal of the current feedback unit is electrically connected to the first input terminal of the first amplifier in the low-dropout linear regulator, and the third terminal of the current feedback unit is electrically connected between the image transistor and the second voltage feedback module in the low-dropout linear regulator; the input terminal of the low-dropout linear regulator is used to receive the input voltage, and the output terminal of the low-dropout linear regulator is used to provide the output voltage; The voltage detector is used to transmit a first current to the current feedback device when it detects that the voltage difference between the input voltage and the output voltage is greater than a threshold voltage. The current feedback device is used to control the output current of the mirror transistor to decrease according to the first current, so as to control the output current of the power transistor in the low dropout linear regulator to decrease, so that the power of the power transistor is less than or equal to the threshold power. The image transistor and the power transistor form a current mirror structure, and the image transistor and the second voltage feedback module are connected in series between the input terminal and the ground terminal; The second input terminal of the first amplifier is used to receive the first reference voltage, the output terminal is electrically connected to the positive terminal of the second diode, and the negative terminal of the second diode is electrically connected to the control terminal of the power transistor.

2. The power control circuit according to claim 1, characterized in that, The voltage detector includes: a second resistor, a third resistor, and a second transistor; The first end of the second resistor is electrically connected between the input terminal of the low dropout linear regulator and the first end of the power transistor. The second end of the second resistor is electrically connected to the first end of the second transistor. The control terminal of the second transistor is electrically connected to the output terminal of the low dropout linear regulator. The second end of the second transistor is electrically connected to the first end of the third resistor. The second end of the third resistor is grounded.

3. The power control circuit according to claim 2, characterized in that, The current feedback device includes: a first diode and a fourth resistor; The first end of the first diode is electrically connected to the third end of the voltage detector, the second end of the first diode is electrically connected to the first input end of the first amplifier, the first end of the fourth resistor is electrically connected between the second end of the first diode and the first input end of the first amplifier, and the second end of the fourth resistor is electrically connected between the mirror transistor and the second voltage feedback module.

4. The power control circuit according to claim 3, characterized in that, The formula for calculating the threshold voltage is: ； in, VREF2 represents the threshold voltage, and VREF2 represents the first reference voltage received at the second input terminal of the first amplifier. This indicates the voltage of the first diode. This indicates the resistance value of the second resistor. This indicates the resistance value of the third resistor.

5. The power control circuit according to claim 4, characterized in that, The formula for calculating the output current of the power transistor is: ； The formula for calculating the power of the power transistor is: ； in, Indicates the output current of the power transistor. ， This represents the ratio of the output current of the power transistor to the output current of the image transistor. This indicates the resistance value of the fourth resistor. This indicates the resistance value of the second voltage feedback module. This represents the input voltage. Indicates the first intermediate value. Indicates the second intermediate value. This indicates the output voltage. This indicates the power of the power transistor.

6. The power control circuit according to claim 5, characterized in that, The formula for calculating the threshold power is: ;in, This represents the threshold power.

7. A method for implementing a power control circuit, characterized in that, The method, applied to the power control circuit according to any one of claims 1 to 6, comprises: When the voltage detector detects that the voltage difference between the input voltage and the output voltage is greater than a threshold voltage, it transmits a first current to the current feedback device. The current feedback device controls the output current of the mirror transistor to decrease based on the first current, thereby controlling the output current of the power transistor to decrease, so that the power of the power transistor is less than or equal to the threshold power.

8. A low-dropout linear voltage regulator, characterized in that, include: The circuit comprises an input terminal, an output terminal, a power transistor, a mirror transistor, a first voltage feedback module, a second voltage feedback module, a first amplifier, a second amplifier, a second diode, and the power control circuit according to any one of claims 1-6. The power transistor is connected in series with the first voltage feedback module between the input terminal and the ground terminal; The image transistor and the power transistor form a current mirror structure, and the image transistor and the second voltage feedback module are connected in series between the input terminal and the ground terminal; The first input terminal of the first amplifier is electrically connected to the second terminal of the current feedback in the power control circuit. The second input terminal is used to receive the first reference voltage. The output terminal is electrically connected to the positive terminal of the second diode. The negative terminal of the second diode is electrically connected to the control terminal of the power transistor. The first input terminal of the second amplifier is coupled to the first voltage feedback module, the second input terminal is used to receive the second reference voltage, and the output terminal is electrically connected to the control terminal of the power transistor.

9. A chip, characterized in that, include: The power control circuit according to any one of claims 1 to 6, or the low dropout linear regulator according to claim 8.

10. An electronic device, characterized in that, include: The chip according to claim 9.

Images