A circuit and method for improving transient load response of a constant voltage power supply

Abstract

The application discloses a circuit and method for improving transient load response of constant voltage power supply, which comprises a voltage regulator and a load balancing structure. The method comprises: when the external load current is in a stable state, the charging diode is in a reverse cut-off state; when the external load current is in an increasing state, the output load voltage of the voltage regulator is in a falling state, the charging diode is in a conducting state, and the energy storage capacitor performs voltage compensation processing on the voltage regulator; and when the external load current is in a decreasing state, the output load voltage of the voltage regulator is in a rising state, and the voltage regulator performs charging processing on the energy storage capacitor. The application can improve the transient load response of the constant voltage power supply, reduce the voltage fluctuation amplitude and accelerate the response speed. The application can be widely applied to the technical field of power supply circuits.

Description

Technical Field

[0001] This invention relates to the field of power supply circuit technology, and in particular to a circuit and method for improving the transient load response of a constant voltage power supply. Background Technology

[0002] With the widespread adoption of internet-connected devices, more and more electronic products require rapid response times. The speed requirements for processors in these products are increasing, making rapid transient load response a pressing power supply need. Currently, many solutions primarily focus on optimizing transient loads in specific scenarios. For example, existing solutions rely on predicting transient loads to proactively respond, requiring the load (CPU or GPU) to actively inform the system of upcoming transient load conditions and then adjusting the reference voltage to minimize voltage transient changes. However, this approach is complex to implement and unsuitable for unpredictable load changes. Existing solutions also include those for Boost-type voltage regulators to improve transient load response, but these are more complex... Complex circuit designs improve the transient load response speed of the regulator circuit, but more complex circuits increase the load-side cost for transient response. For example, existing optimizations for multi-core CPU load reset scenarios use a second load circuit to increase the load current and offset the CPU current change caused by the reset, thereby reducing overshoot voltage. However, during multi-core CPU reset, the load current suddenly decreases, which can easily cause overshoot. Furthermore, current methods that control the load voltage by changing the output capacitor value of the regulator, although a larger output capacitor results in a smaller instantaneous voltage change, significantly affect the response speed of the voltage-controlled current source. Increasing the capacitor will noticeably slow down the response speed of the current source. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a circuit and method for improving the transient load response of a constant voltage power supply, which can improve the transient load response of the constant voltage power supply, reduce voltage fluctuation amplitude, and accelerate response speed.

[0004] The first technical solution adopted in this invention is: a transient load response circuit for improving a constant voltage power supply, comprising a voltage regulator and a load balancing structure, wherein the voltage output terminal of the voltage regulator is connected to the input terminal of the load balancing structure, and the ground terminal of the voltage regulator is connected to the ground terminal of the load balancing structure, wherein:

[0005] The voltage regulator is used to adjust the magnitude of the output load voltage according to the change in the input load current;

[0006] The load balancing structure is used to average the output load voltage of the voltage regulator to obtain an optimized output load voltage.

[0007] Furthermore, the voltage regulator includes an input terminal, a voltage-controlled current source, an input capacitor, a first regulator resistor, a second regulator resistor, an output capacitor, a voltage output terminal, an external load, and an error amplifier. The input terminal is connected to the first terminal of the voltage-controlled current source and the first terminal of the input capacitor. The second terminal of the voltage-controlled current source, the first terminal of the first regulator resistor, and the first terminal of the output capacitor are connected to the voltage output terminal. The third terminal of the voltage-controlled current source is connected to the output terminal of the error amplifier. The second terminal of the input capacitor, the second terminal of the second regulator resistor, and the second terminal of the output capacitor are connected to the second terminal of the external load. The first terminal of the external load is connected to the voltage output terminal. The second terminal of the first regulator resistor and the first terminal of the second regulator resistor are connected to the input terminal of the error amplifier. Wherein:

[0008] The input terminal is used to input an external DC voltage;

[0009] The voltage-controlled current source is used to control the external DC voltage to a nominal voltage value;

[0010] The input capacitor and the output capacitor are used to store the energy of the voltage regulator;

[0011] The first resistor and the second resistor of the regulator are used to reduce the external DC voltage according to a preset ratio.

[0012] The voltage output terminal is used to output the voltage after voltage drop to the external load;

[0013] The error amplifier is used to adjust the output of the voltage-controlled current source.

[0014] Furthermore, the load balancing structure includes an energy storage capacitor, a charging diode, a discharging diode, and a constant current limiting device. The positive terminal of the charging diode is connected to the negative terminal of the discharging diode and is also connected to the voltage output terminal of the voltage regulator. The negative terminal of the charging diode is connected to the first terminal of the constant current limiting device. The positive terminal of the discharging diode and the second terminal of the constant current limiting device are connected to the first terminal of the energy storage capacitor. The second terminal of the energy storage capacitor is grounded and connected to the ground terminal of the voltage regulator.

[0015] The energy storage capacitor is used to provide electrical energy when the voltage drops;

[0016] The charging diode is used to forward charge the energy storage capacitor;

[0017] The discharge diode is used to reverse discharge the voltage regulator.

[0018] The constant current limiting device is used to limit the charging current.

[0019] Furthermore, both the charging diode and the discharging diode are Schottky diodes.

[0020] Furthermore, the constant current limiting device is specifically implemented as any one of the following four electronic circuits:

[0021] The first type of circuit: a transistor circuit that uses the emitter resistor as a fixed bias current;

[0022] The second type of circuit: a MOSFET circuit with a fixed bias voltage;

[0023] The third type of circuit: a depletion-mode MOSFET circuit with a current-limiting resistor;

[0024] The fourth type of circuit: a transistor circuit that uses a depletion-type MOSFET as the transistor with a fixed bias current.

[0025] Furthermore, the transistor circuit using the emitter resistor as a fixed bias current includes a first PNP transistor and a first resistor. The source of the first PNP transistor is connected to the negative terminal of the charging diode, the drain of the first PNP transistor is connected to the first terminal of the energy storage capacitor, the gate of the first PNP transistor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is grounded, wherein:

[0026] The first PNP transistor is used to amplify the charging current;

[0027] The first resistor is used to limit the increase in charging current.

[0028] Furthermore, the MOSFET circuit with a fixed bias voltage includes a Zener diode, a second resistor, and an enhancement-mode MOSFET. The negative terminal of the Zener diode is connected to the positive terminal of the charging diode, the source of the enhancement-mode MOSFET is connected to the negative terminal of the charging diode, the drain of the enhancement-mode MOSFET is connected to the first terminal of the energy storage capacitor, the gate of the enhancement-mode MOSFET and the positive terminal of the Zener diode are connected to the first terminal of the second resistor, and the second terminal of the second resistor is grounded.

[0029] The Zener diode is used to stabilize the charging current;

[0030] The second resistor is used to limit the increase in charging current;

[0031] The enhanced MOSFET is used to regulate the magnitude of the charging current.

[0032] Furthermore, the depletion-type MOSFET circuit with a current-limiting resistor includes a third resistor and a first depletion-type MOSFET. The gate of the first depletion-type MOSFET and the negative terminal of the charging diode are connected to a first terminal of the third resistor. The second terminal of the third resistor is connected to the source of the first depletion-type MOSFET. The drain of the first depletion-type MOSFET is connected to a first terminal of the energy storage capacitor, wherein:

[0033] The third resistor is used to limit the increase in charging current;

[0034] The first depletion-type MOSFET is used to regulate the magnitude of the charging current.

[0035] Furthermore, the transistor circuit using a depletion-type MOSFET as a fixed bias current includes a second PNP transistor, a fourth resistor, and a second depletion-type MOSFET. The source of the second PNP transistor is connected to the negative terminal of the charging diode, the drain of the second PNP transistor is connected to the first terminal of the energy storage capacitor, the gate of the second PNP transistor, the first terminal of the fourth resistor, and the gate of the second depletion-type MOSFET are connected, the second terminal of the fourth resistor is connected to the source of the second depletion-type MOSFET, and the drain of the second depletion-type MOSFET is grounded.

[0036] The second PNP transistor is used to amplify the charging current;

[0037] The fourth resistor is used to limit the increase in charging current;

[0038] The second depletion-type MOSFET is used to regulate the magnitude of the charging current.

[0039] The second technical solution adopted in this invention is: a method for improving the transient load response of a constant voltage power supply, comprising the following steps:

[0040] The ideal output load voltage of the voltage regulator is set to V. set ;

[0041] When the external load current is in a stable state, the output load voltage V of the voltage regulator out Equal to the ideal output load voltage V of the voltage regulator set The charging voltage of the energy storage capacitor is V. set -V on V on This indicates the forward voltage drop of the charging diode, and the charging diode is in a reverse cutoff state;

[0042] When the external load current is increasing, the output load voltage of the voltage regulator is decreasing; when the output load voltage of the voltage regulator decreases to V... set -2V on The charging diode is in the on state, and the energy storage capacitor performs voltage compensation processing on the output load voltage of the voltage regulator;

[0043] When the external load current is decreasing, the output load voltage of the voltage regulator is increasing. The voltage regulator charges the energy storage capacitor through the charging diode and the discharging diode, thereby averaging the output load voltage of the voltage regulator.

[0044] The beneficial effects of the circuit and method of the present invention are as follows: By connecting the voltage regulator and the load balancing structure in parallel, the voltage regulator further adjusts the magnitude of the output load voltage according to the change of the load current. The load balancing structure averages the output load voltage of the voltage regulator. Without changing the regulator itself or the external load, the transient load response of the constant voltage power supply can be improved, the voltage fluctuation amplitude can be reduced, and the response speed can be accelerated. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of a transient load response circuit for improving a constant voltage power supply according to an embodiment of the present invention;

[0046] Figure 2 It is the schematic diagram of an existing power supply circuit;

[0047] Figure 3 This is a schematic diagram of the transient simulation results of an existing power supply circuit with varying load current.

[0048] Figure 4 This is a schematic diagram of the transient simulation results of the existing power supply circuit when a load change current is applied for the nth time.

[0049] Figure 5 This is a circuit diagram of a voltage regulator according to a specific embodiment of the present invention;

[0050] Figure 6 This is a circuit diagram of a load balancing structure according to a specific embodiment of the present invention;

[0051] Figure 7 This is a schematic diagram of a transistor circuit using an emitter resistor as a fixed bias current in a specific embodiment of the present invention.

[0052] Figure 8 This is a schematic diagram of a MOSFET circuit with a fixed bias voltage according to a specific embodiment of the present invention;

[0053] Figure 9 This is a schematic diagram of a depletion-type MOSFET circuit with a current-limiting resistor according to a specific embodiment of the present invention;

[0054] Figure 10 This is a schematic diagram of a transistor circuit using a depletion-type MOSFET as a transistor with a fixed bias current, according to a specific embodiment of the present invention.

[0055] Figure 11 This is a schematic diagram showing the transient simulation results of the transient load response circuit according to a specific embodiment of the present invention;

[0056] Figure 12 This is a flowchart illustrating a method for improving the transient load response of a constant voltage power supply according to an embodiment of the present invention.

[0057] Figure reference numerals: 11. Input terminal; 12. Voltage-controlled current source; 13. Input capacitor; 14. First resistor of regulator; 15. Second resistor of regulator; 16. Output capacitor; 17. Voltage output terminal; 18. External load; 19. Error amplifier; 20. Ground terminal; 21. Input power supply; 22. Switching regulator; 23. Output capacitor of conventional circuit; 24. Fixed load; 25. Transient constant current load; 31. Charging diode; 32. Discharging diode; 33. Constant current limiting device; 34. Energy storage capacitor; 35. Input terminal of load balancing structure; 36. Ground terminal of load balancing structure; 4 0. Transistor circuit using emitter resistor as fixed bias current; 41. First PNP transistor; 42. First resistor; 50. MOSFET circuit with fixed bias voltage; 51. Zener diode; 52. Second resistor; 53. Enhancement-mode MOSFET; 60. Depletion-mode MOSFET circuit with current-limiting resistor; 61. First depletion-mode MOSFET; 62. Third resistor; 70. Transistor circuit using depletion-mode MOSFET as fixed bias current; 71. Second PNP transistor; 72. Fourth resistor; 73. Second depletion-mode MOSFET. Detailed Implementation

[0058] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0059] A traditional power supply circuit such as Figure 2As shown in the diagram, a switching power supply circuit was built using circuit simulation software. It includes an input power supply 21 to provide DC power input, a switching regulator 22 to achieve voltage variation and regulated output, a conventional output capacitor 23 to stabilize the output voltage (in this circuit, it is set to 10uF), a fixed load 24 to meet the minimum load current requirement of the switching regulator (this structure is not necessary for some regulators), and a transient constant current load 25 to simulate the changing load in a real circuit, with the changing current ranging from 0mA to 200mA and a pulse width of 1 millisecond. The transient simulation of this circuit is shown below. Figure 3 As shown, the upper half represents the output voltage change, the lower half represents the pulsed load current, and the horizontal axis represents time. It can be seen that the voltage drops rapidly by about 5V under load, and after the load is removed, the voltage experiences a reverse overshoot of approximately 3V, stabilizing after several oscillations. The same pattern of change occurs when the same load is applied again. When the output capacitor 23 is increased to 100uF and the same load current is applied, the simulation results are as follows... Figure 4 As shown, the output voltage change decreases, dropping by about 1.5V and rebounding by about 1V, while the time required for the voltage to stabilize after the load is removed becomes significantly longer.

[0060] Based on this, refer to Figure 1 This invention provides a transient load response circuit for improving a constant voltage power supply, comprising a voltage regulator and a load balancing structure. The voltage output terminal of the voltage regulator is connected to the input terminal of the load balancing structure, and the ground terminal 20 of the voltage regulator is connected to the ground terminal of the load balancing structure, wherein:

[0061] The voltage regulator is used to adjust the magnitude of the output load voltage according to the change in the input load current;

[0062] Specifically, the voltage regulator includes an input terminal 11, a voltage-controlled current source 12, an input capacitor 13, a first regulator resistor 14, a second regulator resistor 15, an output capacitor 16, a voltage output terminal 17, an external load 18, and an error amplifier 19. The input terminal is connected to the first terminal of the voltage-controlled current source and the first terminal of the input capacitor. The second terminal of the voltage-controlled current source, the first terminal of the first regulator resistor, and the first terminal of the output capacitor are connected to the voltage output terminal. The third terminal of the voltage-controlled current source is connected to the output terminal of the error amplifier. The second terminals of the input capacitor, the second terminals of the second regulator resistor, and the second terminal of the output capacitor are connected to the second terminal of the external load. The first terminal of the external load is connected to the voltage output terminal. The second terminals of the first regulator resistor and the first terminals of the second regulator resistor are connected to the input terminal of the error amplifier. Wherein:

[0063] The input terminal is used to input an external DC voltage; the voltage-controlled current source is used to control the voltage value of the external DC voltage to the nominal voltage; the input capacitor and the output capacitor are used to store the energy of the voltage regulator; the first regulator resistor and the second regulator resistor are used to reduce the voltage of the external DC voltage according to a preset ratio; the voltage output terminal is used to output the reduced voltage to the external load; the error amplifier is used to adjust the output of the voltage-controlled current source.

[0064] In this embodiment, the constant voltage power supply is also commonly referred to as a voltage regulator, and its principle is as follows: Figure 5 As shown. The input terminal is used to input an external DC voltage. To achieve high-precision voltage output, negative feedback technology is usually used to stabilize the output voltage. That is, by using a resistor and proportional voltage reduction, the output voltage is reduced by a certain proportion before being input to one end of the error amplifier. The other end of the error amplifier is input to the reference voltage V. REF Adjust the output current I of the voltage-controlled current source REG This is to maintain the output at the nominal voltage. An external load is connected to the output terminal; in this diagram, a constant current source is used as the load. It should be noted that... Figure 5 This is a general-purpose voltage regulator schematic, applicable to various constant-voltage power supplies, including linear regulators and switching regulators. The constant current source can be implemented using different types of devices. As the required load current changes from zero to full load, the voltage regulator must be able to maintain a constant output voltage, even if the change in load current occurs within a relatively short time; this sudden change in load current is called a load transient. The ability of a voltage regulator to maintain a constant output voltage during a load transient is defined as the load transient response. Using the voltage regulator as a voltage-controlled current source, the current I driven to the load... REG The load current will not change in a short period of time, so if the load current changes rapidly enough, it will force the output voltage to change as well. The transient load response of this circuit system is affected by a variety of factors, which depend on the closed-loop transfer function of the system, namely the speed of the regulator, the number and type of output capacitors, and the di / dt rate of change of the load current.

[0065] The load balancing structure is used to average the output load voltage of the voltage regulator to obtain an optimized output load voltage.

[0066] Specifically, the load balancing structure includes an energy storage capacitor 34, a charging diode 31, a discharging diode 32, and a constant current limiting device 33. The positive terminal of the charging diode is connected to the negative terminal of the discharging diode and is connected to the voltage output terminal of the voltage regulator. The negative terminal of the charging diode is connected to the first terminal of the constant current limiting device. The positive terminal of the discharging diode and the second terminal of the constant current limiting device are connected to the first terminal of the energy storage capacitor. The second terminal of the energy storage capacitor is grounded and connected to the ground terminal of the voltage regulator.

[0067] The load balancing structure in this embodiment of the invention achieves transient load balancing, and its circuit structure is as follows: Figure 6 As shown, the circuit includes a diode for forward charging, a diode for reverse discharging, a constant current passive device for limiting the charging current, and an energy storage capacitor for providing energy when the voltage drops. The circuit structure of this invention can be directly connected in parallel to the original circuit. The common node of the charging and discharging diodes, i.e., the input terminal 35 of the load balancing structure, is connected to the Vout output terminal of the voltage regulator. The ground terminal 36 of the load balancing structure is connected to the ground signal of the voltage regulator.

[0068] It should be added that this invention is more applicable to medium- and high-voltage circuits and circuits with large transient loads, where the voltage drop caused by diode conduction can be ignored. Preferably, the two diodes can be Schottky diodes, which have a smaller forward voltage drop than conventional diodes, further limiting the voltage drop. Preferably, capacitors with smaller equivalent series resistance (ESR) and equivalent series inductance (ESL) should be used to achieve a smaller voltage drop.

[0069] The energy storage capacitor is used to provide electrical energy when the voltage drops; the charging diode is used to forward charge the energy storage capacitor; the discharging diode is used to reverse discharge the voltage regulator; and the constant current limiting device is used to limit the charging current.

[0070] Furthermore, the specific implementation of the constant current limiting device in this embodiment of the invention is any one of the following four electronic circuits: the first circuit is a transistor circuit 40 that uses an emitter resistor as a fixed bias current; the second circuit is a MOSFET circuit 50 with a fixed bias voltage; the third circuit is a depletion-type MOSFET circuit 60 with a current limiting resistor; and the fourth circuit is a transistor circuit 70 that uses a depletion-type MOSFET as a fixed bias current.

[0071] It should be noted that the specific implementation circuit of the constant current limiting device in the embodiments of the present invention includes, but is not limited to, the circuit structure described above.

[0072] In this embodiment, the transistor circuit using an emitter resistor as a fixed bias current includes a first PNP transistor 41 and a first resistor 42. The source of the first PNP transistor is connected to the negative terminal of the charging diode, the drain of the first PNP transistor is connected to the first terminal of the energy storage capacitor, the gate of the first PNP transistor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is grounded. The first PNP transistor is used to amplify the charging current, and the first resistor is used to limit the increase of the charging current.

[0073] Specifically, a transistor circuit that uses the emitter resistor as a fixed bias current, such as... Figure 7 As shown, a PNP transistor and a resistor are used as constant current devices. The constant current charging current can be calculated as follows:

[0074] I = β * (Vout - Von - Vbe) / R

[0075] In the above formula, β is the current amplification factor of the transistor, Von is the forward voltage drop of the diode, Vbe is the forward voltage drop of the transistor, R is the resistance value, I is the constant current charging current, and Vout is the output voltage.

[0076] Connect this circuit to the original circuit and perform a simulation. Set the output capacitor in the original circuit to 10uF, and set the capacitor value of this simulation circuit to 100uF. The result is as follows. Figure 11 As shown, the voltage drop under transient load is about 1.8V, the backlash is about 1V, and the voltage recovery speed is significantly faster. Therefore, it achieves the dual effect of reducing voltage changes and speeding up response time.

[0077] The MOSFET circuit with a fixed bias voltage includes a Zener diode 51, a second resistor 52, and an enhancement-mode MOSFET 53. The negative terminal of the Zener diode is connected to the positive terminal of the charging diode, the source of the enhancement-mode MOSFET is connected to the negative terminal of the charging diode, the drain of the enhancement-mode MOSFET is connected to the first terminal of the energy storage capacitor, the gate of the enhancement-mode MOSFET and the positive terminal of the Zener diode are connected to the first terminal of the second resistor, and the second terminal of the second resistor is grounded. The Zener diode is used to stabilize the charging current; the second resistor is used to limit the increase of the charging current; and the enhancement-mode MOSFET is used to adjust the magnitude of the charging current.

[0078] Specifically, a MOSFET circuit with a fixed bias voltage, such as Figure 8 As shown, a Zener diode, resistor, and enhancement-mode MOSFET are used as the constant current source, utilizing the characteristics of the MOSFET as a voltage-controlled constant current source. The gate bias voltage is Vz-Von, and the charging current is:

[0079] I = kp * (Vz - Von - Vth) 2

[0080] In the above formula, Vz is the Zener diode's Zener voltage, kp is the inherent parameter of the MOSFET, and Vth is the MOSFET's turn-on threshold voltage.

[0081] Given the large variation in Vth during MOSFET manufacturing, this approach is difficult to precisely control the current limiting value and is only suitable for applications where the accuracy of the current limiting value is not critical.

[0082] The depletion-type MOSFET circuit with a current-limiting resistor includes a third resistor 62 and a first depletion-type MOSFET 61. The gate of the first depletion-type MOSFET and the negative terminal of the charging diode are connected to the first end of the third resistor. The second end of the third resistor is connected to the source of the first depletion-type MOSFET. The drain of the first depletion-type MOSFET is connected to the first end of the energy storage capacitor. The third resistor is used to limit the increase of the charging current, and the first depletion-type MOSFET is used to adjust the magnitude of the charging current.

[0083] Specifically, a depletion-mode MOSFET circuit with a current-limiting resistor, such as... Figure 9 As shown, as an improved structure, a single depletion-mode MOSFET is used as the current-limiting element. The current-limiting characteristic can be obtained by directly connecting the source and the gate. The current-limiting value Ion is determined during device manufacturing and has small dispersion. By adding a resistor between the source and the gate and modifying the resistance value, any current-limiting value less than Ion can be obtained. Compared with the enhancement-mode MOSFET, this scheme can obtain a more accurate current-limiting value.

[0084] The transistor circuit using a depletion-type MOSFET as a fixed bias current includes a second PNP transistor 71, a fourth resistor 72, and a second depletion-type MOSFET 73. The source of the second PNP transistor is connected to the negative terminal of the charging diode, the drain of the second PNP transistor is connected to the first terminal of the energy storage capacitor, the gate of the second PNP transistor, the first terminal of the fourth resistor, and the gate of the second depletion-type MOSFET are connected, the second terminal of the fourth resistor is connected to the source of the second depletion-type MOSFET, and the drain of the second depletion-type MOSFET is grounded. The second PNP transistor amplifies the charging current; the fourth resistor limits the increase in the charging current; and the second depletion-type MOSFET adjusts the magnitude of the charging current.

[0085] Specifically, using a depletion-mode MOSFET as a transistor circuit with a fixed bias current is a further improvement to the depletion-mode MOSFET circuit structure with a current-limiting resistor, as follows: Figure 10 As shown, the resistor and depletion-mode MOSFET form a constant current structure. By leveraging the characteristics of the transistor, the controllable current limit is amplified by a factor of β, thus achieving a controllable current limit exceeding the inherent Ion. Compared to transistor circuits with a fixed bias current, the current limit obtained using a depletion-mode MOSFET as the fixed bias current transistor is less affected by output voltage changes, and the charging current during transient processes is more stable, resulting in a better transient response.

[0086] Reference Figure 12 A method for improving the transient load response of a constant voltage power supply includes the following steps:

[0087] S1. Set the ideal output load voltage of the voltage regulator to V. set ;

[0088] S2. When the external load current is in a stable state, the output load voltage V of the voltage regulator out Equal to the ideal output load voltage V of the voltage regulator set The charging voltage of the energy storage capacitor is V. set -V on V on This indicates the forward voltage drop of the charging diode, and the charging diode is in a reverse cutoff state;

[0089] S3. When the external load current is increasing, the output load voltage of the voltage regulator is decreasing. When the output load voltage of the voltage regulator decreases to V... set -2V on The charging diode is in the on state, and the energy storage capacitor performs voltage compensation processing on the output load voltage of the voltage regulator;

[0090] S4. When the external load current is decreasing, the output load voltage of the voltage regulator is increasing. The voltage regulator charges the energy storage capacitor through the charging diode and the discharging diode, thereby averaging the output load voltage of the voltage regulator.

[0091] Specifically, assuming the regulator circuit is set to output voltage V set When the external load is in a stable and constant state, V out =V set The capacitor voltage is charged to V. set -V on V onThe charging diode is in reverse cutoff state due to the forward voltage drop. When the external load current increases rapidly in a short period of time, the regulator itself has a response delay and cannot increase the output current in time, resulting in V... iut The voltage drops rapidly. When V out Descending to V set -2V on At this time, the charging diode starts to conduct, and the energy storage capacitor discharges to the outside through the discharge diode. Since the capacitor can use a relatively large capacitance value, V out The rate of decrease slows significantly until the regulator responds. When the load current suddenly decreases, the regulator charges the capacitor through the discharge and charge diodes. Due to the presence of the current-limiting element, the output capacitor is isolated from the regulator circuit, limiting the charging current to a fixed value. Because the balancing structure limits the capacitor's charging current and prolongs the charging time, it is essentially equivalent to averaging the instantaneous load power, thus resulting in a better voltage response curve.

[0092] The content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0093] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A circuit for improving the transient load response of a constant voltage power supply, characterized in that, The system includes a voltage regulator and a load balancing structure. The voltage output terminal of the voltage regulator is connected to the input terminal of the load balancing structure, and the ground terminal of the voltage regulator is connected to the ground terminal of the load balancing structure. The voltage regulator is used to adjust the magnitude of the output load voltage according to the change in the input load current; The load balancing structure is used to average the output load voltage of the voltage regulator to obtain an optimized output load voltage. The load balancing structure includes an energy storage capacitor, a charging diode, a discharging diode, and a constant current limiting device. The positive terminal of the charging diode is connected to the negative terminal of the discharging diode and is also connected to the voltage output terminal of the voltage regulator. The negative terminal of the charging diode is connected to the first terminal of the constant current limiting device. The positive terminal of the discharging diode and the second terminal of the constant current limiting device are connected to the first terminal of the energy storage capacitor. The second terminal of the energy storage capacitor is grounded and connected to the ground terminal of the voltage regulator. The energy storage capacitor is used to provide electrical energy when the voltage drops; The charging diode is used to forward charge the energy storage capacitor; The discharge diode is used to reverse discharge the voltage regulator. The constant current limiting device is used to limit the charging current.

2. The transient load response circuit for improving a constant voltage power supply according to claim 1, characterized in that, The voltage regulator includes an input terminal, a voltage-controlled current source, an input capacitor, a first regulator resistor, a second regulator resistor, an output capacitor, a voltage output terminal, an external load, and an error amplifier. The input terminal is connected to the first terminal of the voltage-controlled current source and the first terminal of the input capacitor. The second terminal of the voltage-controlled current source, the first terminal of the first regulator resistor, and the first terminal of the output capacitor are connected to the voltage output terminal. The third terminal of the voltage-controlled current source is connected to the output terminal of the error amplifier. The second terminals of the input capacitor, the second terminals of the second regulator resistor, and the second terminal of the output capacitor are connected to the second terminal of the external load. The first terminal of the external load is connected to the voltage output terminal. The second terminals of the first regulator resistor and the first terminals of the second regulator resistor are connected to the input terminal of the error amplifier. Wherein: The input terminal is used to input an external DC voltage; The voltage-controlled current source is used to control the external DC voltage to a nominal voltage value; The input capacitor and the output capacitor are used to store the energy of the voltage regulator; The first resistor and the second resistor of the regulator are used to reduce the external DC voltage according to a preset ratio. The voltage output terminal is used to output the voltage after voltage drop to the external load; The error amplifier is used to adjust the output of the voltage-controlled current source.

3. The transient load response circuit for improving a constant voltage power supply according to claim 1, characterized in that, Both the charging diode and the discharging diode are Schottky diodes.

4. The transient load response circuit for improving a constant voltage power supply according to claim 2, characterized in that, The constant current limiting device is specifically implemented as any one of the following four electronic circuits: The first type of circuit: a transistor circuit that uses the emitter resistor as a fixed bias current; The second type of circuit: a MOSFET circuit with a fixed bias voltage; The third type of circuit: a depletion-mode MOSFET circuit with a current-limiting resistor; The fourth type of circuit: a transistor circuit that uses a depletion-type MOSFET as the transistor with a fixed bias current.

5. The transient load response circuit for improving a constant voltage power supply according to claim 4, characterized in that, The transistor circuit using an emitter resistor as a fixed bias current includes a first PNP transistor and a first resistor. The source of the first PNP transistor is connected to the negative terminal of the charging diode, the drain of the first PNP transistor is connected to the first terminal of the energy storage capacitor, the gate of the first PNP transistor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is grounded. The first PNP transistor is used to amplify the charging current; The first resistor is used to limit the increase in charging current.

6. The transient load response circuit for improving a constant voltage power supply according to claim 4, characterized in that, The MOSFET circuit with a fixed bias voltage includes a Zener diode, a second resistor, and an enhancement-mode MOSFET. The negative terminal of the Zener diode is connected to the positive terminal of the charging diode. The source of the enhancement-mode MOSFET is connected to the negative terminal of the charging diode. The drain of the enhancement-mode MOSFET is connected to the first terminal of the energy storage capacitor. The gate of the enhancement-mode MOSFET and the positive terminal of the Zener diode are connected to the first terminal of the second resistor. The second terminal of the second resistor is grounded. The Zener diode is used to stabilize the charging current; The second resistor is used to limit the increase in charging current; The enhanced MOSFET is used to regulate the magnitude of the charging current.

7. The transient load response circuit for improving a constant voltage power supply according to claim 4, characterized in that, The depletion-mode MOSFET circuit with a current-limiting resistor includes a third resistor and a first depletion-mode MOSFET. The gate of the first depletion-mode MOSFET and the negative terminal of the charging diode are connected to a first terminal of the third resistor. The second terminal of the third resistor is connected to the source of the first depletion-mode MOSFET. The drain of the first depletion-mode MOSFET is connected to a first terminal of the energy storage capacitor, wherein: The third resistor is used to limit the increase in charging current; The first depletion-type MOSFET is used to regulate the magnitude of the charging current.

8. The transient load response circuit for improving a constant voltage power supply according to claim 4, characterized in that, The transistor circuit using a depletion-type MOSFET as a fixed bias current includes a second PNP transistor, a fourth resistor, and a second depletion-type MOSFET. The source of the second PNP transistor is connected to the negative terminal of the charging diode, the drain of the second PNP transistor is connected to the first terminal of the energy storage capacitor, the gate of the second PNP transistor, the first terminal of the fourth resistor, and the gate of the second depletion-type MOSFET are connected, the second terminal of the fourth resistor is connected to the source of the second depletion-type MOSFET, and the drain of the second depletion-type MOSFET is grounded. The second PNP transistor is used to amplify the charging current; The fourth resistor is used to limit the increase in charging current; The second depletion-type MOSFET is used to regulate the magnitude of the charging current.

9. A method for improving the transient load response of a constant voltage power supply, characterized in that, The method is applied to the transient load response circuit according to any one of claims 2-8, and the method includes the following steps: The ideal output load voltage of the voltage regulator is set to ; When the external load current is in a stable state, the output load voltage of the voltage regulator Equal to the ideal output load voltage of the voltage regulator The charging voltage of the energy storage capacitor is , This indicates the forward voltage drop of the charging diode, and the charging diode is in a reverse cutoff state; When the external load current is increasing, the output load voltage of the voltage regulator is decreasing; when the output load voltage of the voltage regulator decreases to... The charging diode is in the on state, and the energy storage capacitor performs voltage compensation processing on the output load voltage of the voltage regulator; When the external load current is decreasing, the output load voltage of the voltage regulator is increasing. The voltage regulator charges the energy storage capacitor through the charging diode and the discharging diode, thereby averaging the output load voltage of the voltage regulator.

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