Linear voltage regulator and voltage regulation method

Abstract

The application discloses a linear voltage regulator and a voltage regulating method, and belongs to the technical field of circuits. The power distribution circuit comprises a controller and N power distribution units connected in series, each power distribution unit comprising a parallelly connected switch tube and a shunt element; the feedback control circuit samples a load voltage and sends a control voltage generated according to the difference between the load voltage and a reference voltage to the controller; the controller controls the conduction state of the switch tube according to the control voltage and an offset control parameter configured for N or N+1 switch tubes, and when it is determined that the voltage difference between the load voltage and a power supply input voltage decreases, the switch tubes are sequentially turned on so that the corresponding shunt elements do not bear the load current; when it is determined that the voltage difference between the load voltage and the power supply input voltage increases, the switch tubes are sequentially turned off so that the corresponding shunt elements bear the load current. The application can disperse the power loss originally concentrated on one switch tube to multiple shunt elements and switch tubes, thereby improving the load capacity.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a linear voltage regulator and voltage regulation method. Background Technology

[0002] Low dropout linear regulators (LDOs) are widely used in DC-DC power supplies, LED driver power supplies, and other applications due to their simple structure, low cost, low output noise, and relatively simple control. A typical linear regulator includes a regulating transistor Q1 and a feedback control circuit. The feedback control circuit samples the output voltage, compares it with a reference voltage, and then controls the gate voltage or base current of the regulating transistor Q1 through a compensation network, thereby maintaining the output voltage at the set value.

[0003] However, in the aforementioned linear regulator, the regulating transistor Q1 bears the entire voltage difference between the input and output voltages. When the input voltage varies widely, the power loss (power dissipation = voltage difference × load current) of the regulating transistor Q1 under high input voltage conditions is very large. This high loss poses a severe challenge to the thermal resistance, heat dissipation capacity, and package size of individual devices, resulting in limited load-carrying capacity of the linear regulator and increased device cost. Summary of the Invention

[0004] This application provides a linear voltage regulator and a voltage regulation method to solve the problem that when the input voltage of a linear voltage regulator varies greatly, a single regulating transistor needs to withstand the entire voltage difference between the input and output voltages. The technical solution is as follows: According to a first aspect of this application, a linear regulator is provided, the linear regulator including a power distribution circuit and a load connected in series between a power supply input terminal and ground; The linear regulator also includes a feedback control circuit; The power distribution circuit includes a controller and N power distribution units connected in series. Each power distribution unit includes a switch and a shunt element connected in parallel. Each output terminal of the controller is connected to the control terminal of a switch, and N≥2. The feedback control circuit is used to sample the load voltage across the load terminals, generate a control voltage based on the difference between the load voltage and the reference voltage, and send the control voltage to the controller. The controller is configured to control the conduction state of the switching transistors based on the control voltage and offset control parameters configured for N or N+1 switching transistors. Specifically, when the control voltage determines that the voltage difference between the load voltage and the supply input voltage decreases, the controller sequentially turns on each switching transistor so that the shunt element corresponding to the switching transistor in the conducting state does not bear the load current; when the control voltage determines that the voltage difference between the load voltage and the supply input voltage increases, the controller sequentially turns off each switching transistor so that the shunt element corresponding to the switching transistor in the off state bears the load current.

[0005] In one possible implementation, when 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the first terminal of the i-th switch, and the output terminal of the (i-1)-th shunt element are connected. The control terminal of the i-th switch is connected to the i-th output terminal of the controller; When 2≤i≤N-1, the output terminal of the i-th shunt element, the input terminal of the (i+1)-th shunt element, and the first terminal of the (i+1)-th switching transistor are connected. The second terminal of the i-th switching transistor is connected to the output terminal of the N-th shunt element; When i=N, the output terminal of the Nth shunt element is connected to the output terminal of the power distribution circuit; Wherein, when the switching transistor is an NMOS, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate; when the switching transistor is an NPN, the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

[0006] In one possible implementation, the linear regulator further includes an (N+1)th switching transistor. When 2≤i≤N, the i-th power distribution unit includes the i-th switching transistor and the i-th shunt element. The input terminal of the i-th shunt element, the first terminal of the i-th switch, and the output terminal of the (i-1)-th shunt element are connected. The control terminal of the i-th switch is connected to the i-th output terminal of the controller; When 2≤i≤N-1, the output terminal of the i-th shunt element, the input terminal of the (i+1)-th shunt element, and the first terminal of the (i+1)-th switch are connected, and the second terminal of the i-th switch is connected to the second terminal of the (N+1)-th switch. When i=N, the output terminal of the Nth shunt element is connected to the first terminal of the (N+1)th switch, and the second terminal of the ith switch is connected to the second terminal of the (N+1)th switch. The control terminal of the (N+1)th switching transistor is connected to the (N+1)th output terminal of the controller; Wherein, when the switching transistor is an NMOS, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate; when the switching transistor is an NPN, the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

[0007] In one possible implementation, when i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The input terminal of the first shunt element and the first terminal of the first switching transistor are connected together to serve as the first input terminal of the power distribution circuit. The output terminal of the first shunt element, the input terminal of the second shunt element, and the first terminal of the second switching transistor are connected. The control terminal of the first switching transistor is connected to the first output terminal of the controller; The input terminal of the controller serves as the second input terminal of the power distribution circuit; When the power distribution circuit does not include the (N+1)th switching transistor, the second terminal of the first switching transistor is connected to the output terminal of the Nth shunt element and serves as the output terminal of the power distribution circuit; when the power distribution circuit includes the (N+1)th switching transistor, the second terminal of the first switching transistor is connected to the second terminal of the (N+1)th switching transistor and serves as the output terminal of the power distribution circuit.

[0008] In one possible implementation, when 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the output terminal of the (i-1)-th shunt element, and the first terminal of the (i-1)-th switching transistor are connected; When 2≤i≤N-1, the output terminal of the i-th shunt element, the first terminal of the i-th switch, and the input terminal of the (i+1)-th shunt element are connected. When i=N, the output terminal of the Nth shunt element and the first terminal of the Nth switching transistor are connected together to serve as the output terminal of the power distribution circuit. The control terminal of the i-th switch is connected to the i-th output terminal of the controller; The second terminal of the i-th switching transistor is connected to the first input terminal of the power distribution circuit; Wherein, when the switching transistor is a PMOS, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate; when the switching transistor is a PNP, the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

[0009] In one possible implementation, when i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The input terminal of the first shunt element is connected to the second terminal of the N switching transistors and then serves as the first input terminal of the power distribution circuit. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the first switching transistor; The control terminal of the first switching transistor is connected to the first output terminal of the controller; The input terminal of the controller serves as the second input terminal of the power distribution circuit.

[0010] In one possible implementation, the linear regulator further includes an (N+1)th switching transistor. When i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The second terminal of the (N+1)th switch is connected to the second terminals of the Nth switch as the first input terminal of the power distribution circuit. The first terminal of the (N+1)th switch is connected to the input terminal of the first shunt element. The control terminal of the (N+1)th switch is connected to the (N+1)th output terminal of the controller. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the first switching transistor; The control terminal of the first switching transistor is connected to the first output terminal of the controller; The input terminal of the controller serves as the second input terminal of the power distribution circuit.

[0011] In one possible implementation, when the power distribution circuit and the load are connected in series... The first input terminal of the power distribution circuit is connected to the power supply input terminal, the second input terminal of the power distribution circuit is connected to the output terminal of the feedback control circuit, the output terminal of the power distribution circuit is connected to the first input terminal of the feedback control circuit and the input terminal of the load, and the second input terminal of the feedback control circuit and the output terminal of the load are grounded.

[0012] In one possible implementation, when the load and the power distribution circuit are connected in series... The input terminal of the load and the first input terminal of the feedback control circuit are respectively connected to the power supply input terminal. The output terminal of the load and the second input terminal of the feedback control circuit are respectively connected to the first input terminal of the power distribution circuit. The second input terminal of the power distribution circuit is connected to the output terminal of the feedback control circuit. The output terminal of the power distribution circuit is grounded.

[0013] According to a second aspect of this application, a voltage regulation method for a linear regulator is provided, for use in the linear regulator described above, the method comprising: The feedback control circuit samples the load voltage across the load terminals, generates a control voltage based on the difference between the load voltage and the reference voltage, and sends the control voltage to the controller. The controller controls the conduction state of the switching transistors based on the control voltage and the offset control parameters configured for N or N+1 switching transistors. Specifically, when the control voltage determines that the voltage difference between the load voltage and the supply input voltage decreases, each switching transistor is turned on sequentially so that the shunt element corresponding to the switching transistor in the on state does not bear the load current; when the control voltage determines that the voltage difference between the load voltage and the supply input voltage increases, each switching transistor is turned off sequentially so that the shunt element corresponding to the switching transistor in the off state bears the load current.

[0014] The beneficial effects of the technical solution provided in this application include at least the following: A structure employing multiple power distribution units connected in series is used. Each power distribution unit includes a switch and a shunt element connected in parallel. When the input voltage increases, the switches are sequentially turned off, allowing the shunt element corresponding to the off-state switch to handle the load current. This distributes the power loss, originally concentrated on a single switch, across multiple shunt elements and the switch. In this way, the heat source is dispersed from a single device to multiple devices, significantly reducing the heat density of a single device, enabling it to withstand larger load currents, and improving its load-carrying capacity.

[0015] By using a common control voltage in conjunction with independent offset control parameters for each switch, orderly control of multiple switches can be achieved without the need for complex multi-channel independent control circuits. The control logic is simple and easy to implement, and since there is only one feedback control loop, the system has good stability and high reliability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a circuit diagram of a linear regulator connected in series according to the power distribution circuit and the load. Figure 2 This is a circuit diagram of a linear regulator connected in series according to the order of load and power distribution circuits; Figure 3This is a circuit diagram of a linear regulator containing N NMOS transistors; Figure 4 This is a circuit diagram of a linear regulator that includes offset voltage control; Figure 5 yes Figure 4 The waveform diagram of the linear regulator shown is shown below; Figure 6 This is a circuit diagram of a linear regulator containing N PMOS transistors. Figure 7 This is a circuit diagram of a linear regulator containing N PNP transistors; Figure 8 This is a circuit diagram of a linear regulator that includes offset current control; Figure 9 This is a circuit diagram of a linear regulator containing N+1 PMOS transistors. Figure 10 This is a flowchart of a voltage regulation method for a linear regulator provided in one embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0019] This application relates to a linear voltage regulator, which may include: a power distribution circuit 110 and a load 120 connected in series, connected to the power supply input terminal V. IN Between and ground (GND). The linear regulator also includes a feedback control circuit 130.

[0020] In this embodiment, the series connection order between the power distribution circuit 110 and the load 120 is not limited. That is, the power distribution circuit 110 can be located on the high-voltage side of the load 120 (i.e., close to the power supply input terminal V). IN One end of the load (i.e., the low-voltage side of the load 120, i.e., the end closest to ground GND).

[0021] Specifically, this embodiment includes, but is not limited to, the following two series topologies.

[0022] (1) Connect the power distribution circuit 110 and the load 120 in series in the order of power distribution circuit 110 and load 120.

[0023] like Figure 1 As shown, when the power distribution circuit 110 and the load 120 are connected in series, the first input terminal of the power distribution circuit 110 is connected to the power supply input terminal V. INThe second input terminal of the power distribution circuit 110 is connected to the output terminal of the feedback control circuit 130. The output terminal of the power distribution circuit 110 is connected to the first input terminal of the feedback control circuit 130 and the input terminal of the load 120, respectively. The second input terminal of the feedback control circuit 130 and the output terminal of the load 120 are grounded to GND.

[0024] In this embodiment, the feedback control circuit 130 includes a voltage divider network and an operational amplifier; the first input terminal of the voltage divider network is connected to the input terminal of the load 120, the second input terminal of the voltage divider network is connected to the output terminal of the load 120, and the output terminal of the voltage divider network is connected to the inverting input terminal V of the operational amplifier. FB Connected, the non-inverting input V of the operational amplifier REF Connected to the reference voltage terminal, the output terminal of the operational amplifier serves as the output terminal of the feedback control circuit 130.

[0025] During operation, the voltage divider network samples the voltage across the load 120 and converts the sampled feedback voltage V into a voltage. FB The input is given to the inverting input of the op-amp. The op-amp will then input V... FB With reference voltage V REF The two values ​​are compared, and a control voltage V is generated based on the difference between them. C The control voltage V C The signal is sent to the second input terminal of the power distribution circuit 110. The power distribution circuit 110 then processes the received control voltage V. C Adjusting the operating state of the internal power distribution unit regulates the voltage output to the load 120, thereby adjusting the load voltage V. OUT It stabilizes at the set value.

[0026] (2) The load 120 and the power distribution circuit 110 are connected in series in the order of load 120 and power distribution circuit 110.

[0027] like Figure 2 As shown, when the load 120 and the power distribution circuit 110 are connected in series, the input terminal of the load 120 and the first input terminal of the feedback control circuit 130 are respectively connected to the power supply input terminal, the output terminal of the load 120 and the second input terminal of the feedback control circuit 130 are respectively connected to the first input terminal of the power distribution circuit 110, the second input terminal of the power distribution circuit 110 is connected to the output terminal of the feedback control circuit 130, and the output terminal of the power distribution circuit 110 is grounded.

[0028] The feedback control circuit 130 is the feedback control circuit described above, but it can also be a feedback control circuit of other structures, which is not limited in this embodiment.

[0029] During operation, the voltage across the load 120 is sampled by the feedback control circuit 130, which then generates a control voltage V based on the sampling result. CAnd send it to the power distribution circuit 110. The power distribution circuit 110 determines the power distribution based on the control voltage V. C Adjusting the operating state of the internal power distribution unit regulates the current flowing through the load 120, thereby adjusting the load voltage V. OUT It stabilizes at the set value.

[0030] Regardless of the topology used, the power distribution circuit 110 can be implemented using any of the following four structures.

[0031] (a) The power distribution circuit 110 includes a controller and N power distribution units connected in series. Each power distribution unit includes a switch and a shunt element connected in parallel, and each output terminal of the controller is connected to the control terminal of a switch, where N ≥ 2.

[0032] A shunt element is used to absorb the voltage difference between the input and output when the switch connected in parallel with it is turned off, and to transfer some or all of the power loss from the switch to itself, dissipating it as heat. A shunt element can be a component with impedance characteristics, such as a resistor, thermistor, varistor, or impedance network. This embodiment uses a resistor as an example for illustration.

[0033] like Figure 2 As shown, the specific structure of the power distribution circuit 110 is as follows: When i=1, the first power distribution unit includes a first switch and a first shunt element. The input terminal of the first shunt element is connected to the first terminal of the first switch and serves as the first input terminal of the power distribution circuit 110. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the second switch. The control terminal of the first switch is connected to the first output terminal of the controller. The input terminal of the controller serves as the second input terminal of the power distribution circuit 110. The second terminal of the first switch is connected to the output terminal of the Nth shunt element and serves as the output terminal of the power distribution circuit 110.

[0034] When 2 ≤ i ≤ N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the first terminal of the i-th switch, and the output terminal of the (i-1)-th shunt element are connected. The control terminal of the i-th switch is connected to the i-th output terminal of the controller. Specifically, when 2 ≤ i ≤ N-1, the output terminal of the i-th shunt element, the input terminal of the (i+1)-th shunt element, and the first terminal of the (i+1)-th switch are connected. The second terminal of the i-th switch is connected to the output terminal of the N-th shunt element. When i = N, the output terminal of the N-th shunt element is connected to the output terminal of the power distribution circuit 110.

[0035] It should be noted that the switching transistor can be Figure 1 or Figure 2The NMOS shown here has the first terminal as the drain, the second terminal as the source, and the control terminal as the gate; or, the switching transistor can also be an NPN (not shown in the figure), in which case the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

[0036] Through the above connection method, N shunt elements R1 to R... N N switching transistors Q1 to Q2 are connected in series between the first input and output terminals of the power distribution circuit 110. N The first terminal is connected to the input terminal of the corresponding shunt element, and N switching transistors Q1 to Q2 are connected. N The second end of each circuit is connected to the output of the power distribution circuit 110.

[0037] Feedback control circuit 130 is used to sample the load voltage across load 120 and generate control voltage V based on the difference between the load voltage and the reference voltage. C The control voltage V C Send to the controller.

[0038] Controller, used to adjust according to control voltage V C The offset control parameters configured for N switching transistors jointly control the on-state of the switching transistors. Specifically, when the switching transistor is an NMOS, the offset control parameter is the offset voltage; when the switching transistor is an NPN, the offset control parameter is the offset current. When based on the control voltage V C When the voltage difference between the load voltage and the supply input voltage decreases, the controller sequentially turns on each switch to ensure that the shunt element corresponding to the turned-on switch does not bear the load current. For example... Figure 1 As shown, the switching transistor Q N The first one to conduct, followed by Q in sequence. N-1 Q N-2 Q1, ...

[0039] When based on the control voltage V C When the voltage difference between the load voltage and the supply input voltage increases, the controller sequentially turns off each switch, allowing the shunt element corresponding to the off-state switch to handle the load current. For example... Figure 1 As shown, switch Q1 turns off first, followed by Q2, Q3, ..., Q... N .

[0040] To control the switching transistors in the power distribution unit to turn on and off sequentially as described above, it is necessary to configure the offset control parameters for each switching transistor. For example... Figure 3 As shown, N=3, meaning the power distribution circuit 110 includes three power distribution units connected in series, corresponding to the first switch Q1, the second switch Q2, and the third switch Q3, respectively. Figure 4As shown, assuming the unit offset voltage is V OS The offset voltages configured for each switch are as follows: the offset voltage configured for the first switch Q1 is 2V. OS The offset voltage configured for the second switch Q2 is V. OS The offset voltage configured for the third switch Q3 is 0.

[0041] The controller receives control voltage V from the feedback control circuit 130. C and control voltage V C The offset control parameters corresponding to each switching transistor are superimposed to generate the control signal for each switching transistor. Since the offset control parameters are different for each switching transistor, when the control voltage V... C When the voltage gradually changes from high to low, each switching transistor will operate at different control voltages V. C State reversal occurs at the threshold: when the control voltage V C When the voltage is high, all switching transistors meet the conduction condition and are fully turned on; when the control voltage V... C When the voltage drops to a certain threshold, the switch with the smallest offset voltage is the first to exit the saturation region and begin to turn off; when the control voltage V... C Further reducing the offset voltage, the second switch Q2, which has the next lowest offset voltage, is turned off; when the control voltage V C When the voltage drops to its lowest level, the first switch Q1, which has the largest offset voltage, also turns off. Similarly, when the control voltage V... C As the voltage gradually increases from low to high, the switching transistors turn on in reverse order: the third switching transistor Q3 turns on first, followed by the second switching transistor Q2, and finally the first switching transistor Q1.

[0042] When the power supply input voltage V IN After exceeding a certain range, the output voltage V OUT Instead of remaining constant, it follows the supply input voltage V with a basically fixed voltage difference. IN The change in voltage difference is equal to the product of the load current and the sum of the resistances of all shunt components, i.e.: V OUT = V IN - I load × (R1 + R2 + R3). At this point, most of the input voltage drops across the series-connected external shunt elements R1, R2, and R3. The power loss is mainly borne by these shunt elements, greatly reducing the losses of the subsequent regulator.

[0043] This solution is particularly suitable for applications where the downstream stage still requires adjustment capabilities, such as LED (Light Emitting Diode) drivers. In LED driver applications, LEDs themselves have a certain current regulation capability, and the accuracy requirements for the supply voltage are relatively low. Using the above solution, an external shunt resistor can bear most of the voltage drop, thereby reducing the power consumption and heat generation of the driver chip, and improving the system's reliability and load capacity.

[0044] By using the above control method, within a wide range of input voltage variations, multiple shunt elements are used to share the losses of excess voltage difference, resulting in lower losses for each switching transistor under the same load current.

[0045] (b) The power distribution circuit 110 includes a controller, N power distribution units connected in series and an N+1th switching transistor. Each power distribution unit includes a switching transistor and a shunt element connected in parallel, and each output terminal of the controller is connected to the control terminal of a switching transistor, where N≥2.

[0046] like Figure 1 As shown, the specific structure of the power distribution circuit 110 is as follows: When i=1, the first power distribution unit includes a first switch and a first shunt element. The input terminal of the first shunt element is connected to the first terminal of the first switch and serves as the first input terminal of the power distribution circuit 110. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the second switch. The control terminal of the first switch is connected to the first output terminal of the controller. The input terminal of the controller serves as the second input terminal of the power distribution circuit 110. The second terminal of the first switch is connected to the second terminal of the (N+1)th switch and serves as the output terminal of the power distribution circuit 110.

[0047] When 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the first terminal of the i-th switch, and the output terminal of the (i-1)-th shunt element are connected. The control terminal of the i-th switch is connected to the i-th output terminal of the controller. When 2≤i≤N-1, the output terminal of the i-th shunt element, the input terminal of the (i+1)-th shunt element, and the first terminal of the (i+1)-th switch are connected. The second terminal of the i-th switch is connected to the second terminal of the (N+1)-th switch. When i=N, the output terminal of the N-th shunt element is connected to the first terminal of the (N+1)-th switch, and the second terminal of the i-th switch is connected to the second terminal of the (N+1)-th switch. The control terminal of the (N+1)-th switch is connected to the (N+1)-th output terminal of the controller.

[0048] It should be noted that the switching transistor can be Figure 1 or Figure 2The NMOS shown here has the first terminal as the drain, the second terminal as the source, and the control terminal as the gate; or, the switching transistor can also be an NPN, in which case the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

[0049] Through the above connection method, N shunt elements R1 to R... N and the (N+1)th switch Q N+1 N switching transistors Q1 to Q2 are connected in series between the first input and output terminals of the power distribution circuit 110. N The first terminal is connected to the input terminal of the corresponding shunt element, and N+1 switching transistors Q1 to Q... N+1 The second end of each circuit is connected to the output of the power distribution circuit 110.

[0050] The following is combined with Figure 4 The working principle of a linear voltage regulator is explained.

[0051] Assuming the initial power supply input voltage V IN When the load voltage is lower than the rated voltage reference value (i.e., the target output voltage) of the load 120, the feedback control circuit 130 detects the load voltage V. OUT Below the reference voltage V REF Closed-loop control will control voltage V C It rises to its highest value. In this state, due to the control voltage V... C At the highest level, the gate voltages of all switches output by the controller are higher than their turn-on thresholds, and all three switches—Q1, Q2, and Q3—are turned on. Since the on-resistance of the switches is much smaller than that of the parallel shunt elements (resistors R1, R2, and R3), the load current mainly flows through the switches. Specifically, approximately the entire load current flows through the first switch Q1, while the second and third switches Q2 are also turned on, but the current flowing through them is smaller. At this time, each shunt element R1, R2, and R3 is short-circuited by its corresponding switch, and the voltage drop across them is almost zero.

[0052] When the power supply input voltage V IN When the load voltage gradually increases and exceeds the reference value, the feedback control circuit 130 detects the load voltage V. OUT The voltage is trending upwards; to maintain output voltage stability, the closed-loop control begins to reduce the control voltage V. C Since the second switch Q2 is still fully on, the second shunt element R2 connected in parallel with it is short-circuited. At this time, the first shunt element R1 begins to share part of the load current: part of the load current flows through the first switch Q1, and the other part flows through the first shunt element R1. With the control voltage V... CAs the current decreases, the conduction of the first switching transistor Q1 gradually weakens, the current flowing through it gradually decreases, while the current flowing through the first shunt element R1 increases accordingly.

[0053] When the power supply input voltage V IN The voltage is further increased so that when the first shunt element R1 carries the full load current, the first switch Q1 is essentially off. At this time, the full load current flows through the first shunt element R1, and the voltage drop across the first shunt element R1 is I. load ×R1, this voltage drop absorbs part of the voltage difference between the input and output. With the supply input voltage V... IN As the voltage continues to rise, the current flowing through the first shunt element R1 remains the load current, and the remaining input-output voltage difference needs to be borne by subsequent circuitry. Therefore, the feedback control circuit 130 continues to reduce the control voltage V. C This causes the second switch Q2 to enter the linear region, and the current flowing through the second switch Q2 gradually decreases, while the current flowing through the second shunt element R2 gradually increases. At this time, the first shunt elements R1 and R2 jointly bear the input-output voltage difference.

[0054] When the power supply input voltage V IN As the current continues to rise, until the second shunt element R2 also carries the entire load current, both the first switch Q1 and the second switch Q2 are in the off state. At this time, the entire load current flows through the first shunt element R1 and the second shunt element R2, and the first shunt element R1 and the second shunt element R2 jointly bear the input-output voltage difference. When the supply input voltage V... IN As the voltage continues to rise, the feedback control circuit 130 will further reduce the control voltage V. C This is to control the third switch Q3 to enter the saturation region. At this time, the third switch Q3 bears excess input voltage, and its drain-source voltage V DS The remaining input-output voltage difference is absorbed. In this state, the third switch Q3, the first shunt element R1, and the second shunt element R2 all carry load current, and the three share the power loss. Figure 5 The waveform diagram of the voltage change mentioned above is shown.

[0055] (c) The power distribution circuit 110 includes a controller and N power distribution units connected in series. Each power distribution unit includes a switch and a shunt element connected in parallel. Each output terminal of the controller is connected to the control terminal of a switch, and N≥2.

[0056] like Figure 6 and Figure 7 As shown, assuming N=3, the specific structure of the power distribution circuit 110 is as follows: When i=1, the first power distribution unit includes a first switching transistor and a first shunt element. The input terminal of the first shunt element is connected to the second terminals of N switching transistors and serves as the first input terminal of the power distribution circuit 110. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the first switching transistor. The control terminal of the first switching transistor is connected to the first output terminal of the controller. The input terminal of the controller serves as the second input terminal of the power distribution circuit 110.

[0057] When 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the output terminal of the (i-1)-th shunt element, and the first terminal of the (i-1)-th switch are connected. When 2≤i≤N-1, the output terminal of the i-th shunt element, the first terminal of the i-th switch, and the input terminal of the (i+1)-th shunt element are connected. When i=N, the output terminal of the N-th shunt element and the first terminal of the N-th switch are connected as the output terminal of the power distribution circuit 110. The control terminal of the i-th switch is connected to the i-th output terminal of the controller. The second terminal of the i-th switch is connected to the first input terminal of the power distribution circuit 110.

[0058] It should be noted that the switching transistor can be Figure 6 The PMOS shown here has the first terminal as the drain, the second terminal as the source, and the control terminal as the gate; alternatively, the switching transistor could also be... Figure 7 The PNP shown here has the first terminal as the collector, the second terminal as the emitter, and the control terminal as the base.

[0059] Through the above connection method, N shunt elements R1 to R... N N switching transistors Q1 to Q2 are connected in series between the first input and output terminals of the power distribution circuit 110. N The first terminal is connected to the output terminal of the corresponding shunt element, and N switching transistors Q1 to Q2 are connected to the output terminal of the corresponding shunt element. N The second end of each circuit is connected to the input of the power distribution circuit 110.

[0060] Feedback control circuit 130 is used to sample the load voltage across load 120 and generate control voltage V based on the difference between the load voltage and the reference voltage. C The control voltage V C Send to the controller.

[0061] Controller, used to adjust according to control voltage V C The offset control parameters configured for N switching transistors jointly control the on-state of the switching transistors. Specifically, when the switching transistor is a PMOS, the offset control parameter is the offset voltage; when the switching transistor is a PNP, the offset control parameter is the offset current. When based on the control voltage V CWhen the voltage difference between the load voltage and the supply input voltage decreases, the controller sequentially turns on each switch to ensure that the shunt element corresponding to the turned-on switch does not bear the load current. For example... Figure 6 and Figure 7 As shown, switch Q1 turns on first, followed by Q2 and Q3 in sequence.

[0062] When based on the control voltage V C When the voltage difference between the load voltage and the supply input voltage increases, the controller sequentially turns off each switch, allowing the shunt element corresponding to the off-state switch to handle the load current. For example... Figure 6 and Figure 7 As shown, switch Q3 turns off first, followed by Q2 and Q1 in sequence.

[0063] To control the switching transistors in the power distribution unit to turn on and off sequentially as described above, it is necessary to configure the offset control parameter, i.e., the offset current, for each switching transistor. However, the offset current is essentially determined by the offset voltage; therefore, the offset voltage can still be used to indirectly characterize this configuration. For example... Figure 8 As shown, N=3, meaning the power distribution circuit 110 includes three power distribution units connected in series, corresponding to the first switch Q1, the second switch Q2, and the third switch Q3, respectively. Assume the unit offset voltage is V. OS The offset voltages configured for each switch are as follows: the offset voltage configured for the first switch Q1 is 0; the offset voltage configured for the second switch Q2 is V. OS The offset voltage configured for the third switch Q3 is 2V. OS .

[0064] By using the above control method, within a wide range of input voltage variations, multiple shunt elements are used to share the losses of excess voltage difference, resulting in lower losses for each switching transistor under the same load current.

[0065] (d) The power distribution circuit 110 includes a controller, N power distribution units connected in series and an N+1th switching transistor. Each power distribution unit includes a switching transistor and a shunt element connected in parallel, and each output terminal of the controller is connected to the control terminal of a switching transistor, where N≥2.

[0066] like Figure 9 As shown, assuming N=3, the specific structure of the power distribution circuit 110 is as follows: When i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The second terminal of the (N+1)th switching transistor is connected to the second terminals of the N switching transistors and serves as the first input terminal of the power distribution circuit 110. The first terminal of the (N+1)th switching transistor is connected to the input terminal of the first shunt element. The control terminal of the (N+1)th switching transistor is connected to the (N+1)th output terminal of the controller. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the first switching transistor. The control terminal of the first switching transistor is connected to the first output terminal of the controller. The input terminal of the controller serves as the second input terminal of the power distribution circuit 110.

[0067] When 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the output terminal of the (i-1)-th shunt element, and the first terminal of the (i-1)-th switch are connected. When 2≤i≤N-1, the output terminal of the i-th shunt element, the first terminal of the i-th switch, and the input terminal of the (i+1)-th shunt element are connected. When i=N, the output terminal of the N-th shunt element and the first terminal of the N-th switch are connected as the output terminal of the power distribution circuit 110. The control terminal of the i-th switch is connected to the i-th output terminal of the controller. The second terminal of the i-th switch is connected to the first input terminal of the power distribution circuit 110.

[0068] It should be noted that the switching transistor can be Figure 9 The PMOS shown here has the first terminal as the drain, the second terminal as the source, and the control terminal as the gate; or, the switching transistor can also be a PNP, in which case the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

[0069] With the above connection method, the N+1th switching transistor Q... N+1 and N shunt elements R1 to R N N switching transistors Q1 to Q2 are connected in series between the first input and output terminals of the power distribution circuit 110. N The first terminal is connected to the output terminal of the corresponding shunt element, and N+1 switching transistors Q1 to Q2 are connected to the output terminal of the corresponding shunt element. N+1 The second end of each circuit is connected to the input of the power distribution circuit 110.

[0070] It should be noted that when the switching transistor is a PMOS or NMOS, the controller is a gate controller; when the switching transistor is a PNP or NPN, the controller is a base current controller.

[0071] In summary, the linear regulator provided in this application adopts a structure of multiple power distribution units connected in series. Each power distribution unit includes a switching transistor and a shunt element connected in parallel. Thus, when the input voltage increases, the switching transistors are sequentially turned off, allowing the shunt element corresponding to the off-state switching transistor to bear the load current. This disperses the power loss originally concentrated on one switching transistor across multiple shunt elements and the switching transistor. In this way, the heat source is distributed from a single device to multiple devices, significantly reducing the heat density of a single device, enabling it to withstand larger load currents, and improving its load-carrying capacity.

[0072] By using a common control voltage in conjunction with independent offset control parameters for each switch, orderly control of multiple switches can be achieved without the need for complex multi-channel independent control circuits. The control logic is simple and easy to implement, and since there is only one feedback control loop, the system has good stability and high reliability.

[0073] like Figure 10 The diagram illustrates a flowchart of a voltage regulation method for a linear regulator provided in one embodiment of this application. The voltage regulation method for the linear regulator includes: Step 1001: The feedback control circuit samples the load voltage across the load terminals, generates a control voltage based on the difference between the load voltage and the reference voltage, and sends the control voltage to the controller.

[0074] The feedback control circuit samples the load voltage V across the load terminals. OUT The load voltage V OUT With reference voltage V REF The two values ​​are compared, and a control voltage V is generated based on the difference between them. C When the load voltage V OUT Below the reference voltage V REF At that time, control voltage V C Increase; when the load voltage V OUT Higher than the reference voltage V REF At that time, control voltage V C The feedback control circuit will reduce the generated control voltage V. C Send to the controller.

[0075] Step 1002: The controller controls the conduction state of the switching transistors based on the control voltage and the offset control parameters configured for N or N+1 switching transistors. Specifically, when the voltage difference between the load voltage and the supply input voltage decreases according to the control voltage, each switching transistor is turned on sequentially so that the shunt element corresponding to the switching transistor in the conducting state does not bear the load current; when the voltage difference between the load voltage and the supply input voltage increases according to the control voltage, each switching transistor is turned off sequentially so that the shunt element corresponding to the switching transistor in the off state bears the load current.

[0076] The controller receives control voltage V C This is then superimposed with the pre-configured offset control parameters of each switch to generate a control signal for each switch. Since the offset control parameters are different for each switch, when the control voltage V... C When the voltage difference changes from high to low or from low to high, the switching transistors will turn off or turn on in a preset order: when the voltage difference decreases, the switching transistors will turn on in sequence; when the voltage difference increases, the switching transistors will turn off in sequence.

[0077] In summary, the voltage regulation method for the linear regulator provided in this application adopts a structure of multiple power distribution units connected in series. Each power distribution unit includes a switching transistor and a shunt element connected in parallel. Thus, when the input voltage increases, the switching transistors are sequentially turned off, allowing the shunt element corresponding to the off-state switching transistor to bear the load current. This disperses the power loss originally concentrated on a single switching transistor across multiple shunt elements and the switching transistor. In this way, the heat source is distributed from a single device to multiple devices, significantly reducing the heat density of a single device, enabling it to withstand larger load currents, and improving its load-carrying capacity.

[0078] By using a common control voltage in conjunction with independent offset control parameters for each switch, orderly control of multiple switches can be achieved without the need for complex multi-channel independent control circuits. The control logic is simple and easy to implement, and since there is only one feedback control loop, the system has good stability and high reliability.

[0079] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0080] The above description is not intended to limit the embodiments of this application. Any adjustments, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A linear voltage regulator, characterized in that, The linear regulator includes a power distribution circuit and a load connected in series between the power input terminal and ground; The linear regulator also includes a feedback control circuit; The power distribution circuit includes a controller and N power distribution units connected in series. Each power distribution unit includes a switch and a shunt element connected in parallel. Each output terminal of the controller is connected to the control terminal of a switch, and N≥2. The feedback control circuit is used to sample the load voltage across the load terminals, generate a control voltage based on the difference between the load voltage and the reference voltage, and send the control voltage to the controller. The controller is configured to control the conduction state of the switching transistors based on the control voltage and offset control parameters configured for N or N+1 switching transistors. Specifically, when the control voltage determines that the voltage difference between the load voltage and the supply input voltage decreases, the controller sequentially turns on each switching transistor so that the shunt element corresponding to the switching transistor in the conducting state does not bear the load current; when the control voltage determines that the voltage difference between the load voltage and the supply input voltage increases, the controller sequentially turns off each switching transistor so that the shunt element corresponding to the switching transistor in the off state bears the load current.

2. The linear voltage regulator according to claim 1, characterized in that, When 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the first terminal of the i-th switch, and the output terminal of the (i-1)-th shunt element are connected. The control terminal of the i-th switch is connected to the i-th output terminal of the controller; When 2≤i≤N-1, the output terminal of the i-th shunt element, the input terminal of the (i+1)-th shunt element, and the first terminal of the (i+1)-th switch are connected, and the second terminal of the i-th switch is connected to the output terminal of the N-th shunt element. When i=N, the output terminal of the Nth shunt element is connected to the output terminal of the power distribution circuit; Wherein, when the switching transistor is an NMOS, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate; when the switching transistor is an NPN, the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

3. The linear voltage regulator according to claim 1, characterized in that, The linear regulator also includes an (N+1)th switching transistor. When 2≤i≤N, the i-th power distribution unit includes the i-th switching transistor and the i-th shunt element. The input terminal of the i-th shunt element, the first terminal of the i-th switch, and the output terminal of the (i-1)-th shunt element are connected. The control terminal of the i-th switch is connected to the i-th output terminal of the controller; When 2≤i≤N-1, the output terminal of the i-th shunt element, the input terminal of the (i+1)-th shunt element, and the first terminal of the (i+1)-th switch are connected, and the second terminal of the i-th switch is connected to the second terminal of the (N+1)-th switch. When i=N, the output terminal of the Nth shunt element is connected to the first terminal of the (N+1)th switch, and the second terminal of the ith switch is connected to the second terminal of the (N+1)th switch. The control terminal of the (N+1)th switching transistor is connected to the (N+1)th output terminal of the controller; Wherein, when the switching transistor is an NMOS, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate; when the switching transistor is an NPN, the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

4. The linear voltage regulator according to claim 2 or 3, characterized in that, When i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The input terminal of the first shunt element and the first terminal of the first switching transistor are connected together to serve as the first input terminal of the power distribution circuit. The output terminal of the first shunt element, the input terminal of the second shunt element, and the first terminal of the second switching transistor are connected. The control terminal of the first switching transistor is connected to the first output terminal of the controller; The input terminal of the controller serves as the second input terminal of the power distribution circuit; When the power distribution circuit does not include the (N+1)th switching transistor, the second terminal of the first switching transistor is connected to the output terminal of the Nth shunt element and serves as the output terminal of the power distribution circuit; when the power distribution circuit includes the (N+1)th switching transistor, the second terminal of the first switching transistor is connected to the second terminal of the (N+1)th switching transistor and serves as the output terminal of the power distribution circuit.

5. The linear voltage regulator according to claim 1, characterized in that, When 2≤i≤N, the i-th power distribution unit includes the i-th switch and the i-th shunt element. The input terminal of the i-th shunt element, the output terminal of the (i-1)-th shunt element, and the first terminal of the (i-1)-th switching transistor are connected; When 2≤i≤N-1, the output terminal of the i-th shunt element, the first terminal of the i-th switch, and the input terminal of the (i+1)-th shunt element are connected. When i=N, the output terminal of the Nth shunt element and the first terminal of the Nth switching transistor are connected together to serve as the output terminal of the power distribution circuit. The control terminal of the i-th switch is connected to the i-th output terminal of the controller; The second terminal of the i-th switching transistor is connected to the first input terminal of the power distribution circuit; Wherein, when the switching transistor is a PMOS, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate; when the switching transistor is a PNP, the first terminal is the collector, the second terminal is the emitter, and the control terminal is the base.

6. The linear voltage regulator according to claim 5, characterized in that, When i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The input terminal of the first shunt element is connected to the second terminal of the N switching transistors and then serves as the first input terminal of the power distribution circuit. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the first switching transistor; The control terminal of the first switching transistor is connected to the first output terminal of the controller; The input terminal of the controller serves as the second input terminal of the power distribution circuit.

7. The linear voltage regulator according to claim 5, characterized in that, The linear regulator also includes an (N+1)th switching transistor. When i=1, the first power distribution unit includes the first switching transistor and the first shunt element. The second terminal of the (N+1)th switch is connected to the second terminals of the Nth switch as the first input terminal of the power distribution circuit. The first terminal of the (N+1)th switch is connected to the input terminal of the first shunt element. The control terminal of the (N+1)th switch is connected to the (N+1)th output terminal of the controller. The output terminal of the first shunt element and the input terminal of the second shunt element are connected to the first terminal of the first switching transistor; The control terminal of the first switching transistor is connected to the first output terminal of the controller; The input terminal of the controller serves as the second input terminal of the power distribution circuit.

8. The linear regulator according to claim 1, characterized in that, When the power distribution circuit and the load are connected in series, The first input terminal of the power distribution circuit is connected to the power supply input terminal, the second input terminal of the power distribution circuit is connected to the output terminal of the feedback control circuit, the output terminal of the power distribution circuit is connected to the first input terminal of the feedback control circuit and the input terminal of the load, and the second input terminal of the feedback control circuit and the output terminal of the load are grounded.

9. The linear voltage regulator according to claim 1, characterized in that, When the load and the power distribution circuit are connected in series, The input terminal of the load and the first input terminal of the feedback control circuit are respectively connected to the power supply input terminal. The output terminal of the load and the second input terminal of the feedback control circuit are respectively connected to the first input terminal of the power distribution circuit. The second input terminal of the power distribution circuit is connected to the output terminal of the feedback control circuit. The output terminal of the power distribution circuit is grounded.

10. A voltage regulation method for a linear voltage regulator, characterized in that, For use in a linear regulator as described in any one of claims 1 to 9, the method comprises: The feedback control circuit samples the load voltage across the load terminals, generates a control voltage based on the difference between the load voltage and the reference voltage, and sends the control voltage to the controller. The controller controls the conduction state of the switching transistors based on the control voltage and the offset control parameters configured for N or N+1 switching transistors. Specifically, when the control voltage determines that the voltage difference between the load voltage and the supply input voltage decreases, each switching transistor is turned on sequentially so that the shunt element corresponding to the switching transistor in the on state does not bear the load current; when the control voltage determines that the voltage difference between the load voltage and the supply input voltage increases, each switching transistor is turned off sequentially so that the shunt element corresponding to the switching transistor in the off state bears the load current.

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