A power drive circuit and chip

Abstract

This utility model discloses a power supply driving circuit and chip, comprising: a current detection module connected to a power supply module, which detects the output current of the power supply module, compares the output current with a reference current, and outputs a first comparison result; a voltage divider module connected to the power supply module, wherein the voltage at the voltage divider output terminal represents the power supply voltage of the power supply module; an adjustment module connected to the current detection module, which adjusts the voltage division ratio of the first voltage at the voltage divider output terminal in the voltage divider module according to the first comparison result; a comparison module connected to the voltage divider output terminal, which compares the voltage at the voltage divider output terminal with a first reference voltage and outputs a second comparison result; and a control module connected to the comparison module, which controls the output current and power supply voltage according to the second comparison result. Through the implementation of this utility model, while meeting the driving requirements of outputting a constant current or constant voltage, the impedance matching between the current detection path and the voltage feedback path is achieved, thereby improving the stability of the output constant current or constant voltage.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit technology, specifically to a power drive circuit and chip. Background Technology

[0002] In electronic systems such as power management, battery charging, and LED driving, dual-mode control (constant current mode and constant voltage mode) is a core function. Traditional solutions require precise detection of the output current / voltage and rapid adjustment of control parameters to avoid device damage or performance degradation. Existing technologies typically use operational amplifier comparator circuits to achieve mode switching. In constant voltage control, the output voltage is compared with a reference voltage and stabilized through a feedback loop. In constant current control, the voltage drop across the sampling resistor is compared with the voltage across the current reference converter to limit the current. However, when the system switches to constant current mode, the equivalent sense current of the reference voltage or sampling resistor needs to be adjusted. This changes the DC operating point at the operational amplifier input, leading to comparator response delay or increased error. Furthermore, modifying the reference signal can decrease loop stability, causing oscillations and impedance mismatch between the current sensing path and the voltage feedback path. Utility Model Content

[0003] The purpose of this utility model embodiment is to provide a power drive circuit and chip to solve the above-mentioned problems. This utility model embodiment achieves the above objective through the following technical solutions.

[0004] This utility model embodiment provides a power supply driving circuit, including: a current detection module connected to a power supply module, which detects the output current of the power supply module, compares the output current with a reference current, and outputs a first comparison result; a voltage divider module connected to the power supply module, wherein the voltage at its voltage divider output terminal represents the power supply voltage of the power supply module; an adjustment module connected to the current detection module, which adjusts the voltage division ratio of the first voltage at the voltage divider output terminal in the voltage divider module according to the first comparison result; a comparison module connected to the voltage divider output terminal, which compares the voltage at the voltage divider output terminal with a first reference voltage and outputs a second comparison result; and a control module connected to the comparison module, which controls the output current and power supply voltage according to the second comparison result.

[0005] In some embodiments, the current detection module includes: a detection unit connected to the source and drain terminals of the power transistor of the power module, respectively, for detecting a second voltage characterizing the magnitude of the output current; and a comparison unit connected to the detection unit for comparing the second voltage with a second reference voltage and outputting a first comparison result, wherein the second reference voltage characterizes the magnitude of the reference current.

[0006] In some embodiments, the power drive circuit further includes a switching transistor connected to the power module and the control module respectively. The control module controls the switching transistor according to the second comparison result to control the output current and the power supply voltage.

[0007] In some embodiments, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal is increased in the voltage divider module.

[0008] In some embodiments, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal in the voltage divider module is gradually increased according to the first preset step size until the output current is less than the reference current.

[0009] In some embodiments, when the output current is less than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal in the voltage divider module is gradually reduced according to the second preset step size until the output current is greater than the reference current. During the gradual increase of the output current, the power supply voltage is always less than the power supply voltage of the power supply module when it is in a constant voltage state.

[0010] In some embodiments, the voltage divider module includes multiple resistor units and multiple switches. The multiple resistor units are connected to the power supply module, and the multiple switches are connected to the adjustment module. The adjustment module adjusts the voltage division ratio of the first voltage at the voltage divider output terminal in the voltage divider module by controlling the on / off state of the multiple switches. The common terminal formed by two resistor units among the multiple resistor units serves as the voltage divider output terminal.

[0011] In some embodiments, each resistor unit is connected in parallel with a switch.

[0012] In some embodiments, the power module is a flyback switching power supply secondary output circuit.

[0013] This utility model embodiment also provides a power driver chip, including the power driver circuit provided in any of the above embodiments.

[0014] Compared to existing technologies, the power drive circuit and chip provided in this embodiment enable the adjustment of the power supply voltage by adjusting the voltage division ratio of the voltage divider module without the need for separate current control circuits and voltage control circuits. This allows for control of the output current, ensuring that the output current reaches a preset value. The power drive circuit can meet the driving requirements for constant output current or constant voltage. Furthermore, during the control process, there is no need to adjust the equivalent detection current of the reference voltage or sampling resistor, which does not change the DC operating point of the operational amplifier input, resulting in a smaller comparator response delay or error. It also enables impedance matching between the current detection path and the voltage feedback path, improving the stability of the output constant current or constant voltage. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a module of the power drive circuit provided in this embodiment;

[0017] Figure 2 This is a schematic diagram of the power drive circuit provided in this embodiment;

[0018] Figure 3 This is another schematic diagram of the power drive circuit provided in this embodiment;

[0019] Figure 4 This is a schematic diagram of the voltage divider module in the power drive circuit provided in this embodiment. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0021] The term "coupled" or "connected" in this invention includes both direct and indirect connections, such as connections made through active devices, passive devices, or electrical conduction media; it may also include connections made by other active or passive devices that are known to those skilled in the art and can achieve the same or similar functional purpose, such as connections made through switches, follower circuits, or other circuits or components.

[0022] Please see Figure 1This utility model provides a power supply drive circuit, including a current detection module 11, a voltage divider module 12, an adjustment module 13, a comparison module 14, and a control module 15. The current detection module 11 is connected to the power supply module 10, detects the output current of the power supply module 10, compares the output current with a reference current, and outputs a first comparison result. The voltage divider module 12 is connected to the power supply module 10, and the voltage at its voltage divider output terminal Vx represents the power supply voltage of the power supply module 10. The adjustment module 13 is connected to the current detection module 11, and adjusts the voltage division ratio of the first voltage at the voltage divider output terminal Vx in the voltage divider module 12 according to the first comparison result. The comparison module 14 is connected to the voltage divider output terminal Vx, compares the voltage at the voltage divider output terminal Vx with a first reference voltage, and outputs a second comparison result. The control module 15 is connected to the comparison module 14, and controls the output current and power supply voltage according to the second comparison result.

[0023] In this embodiment, the power module 10 may include a forward switching power supply, a flyback switching power supply, a push-to-free switching power supply, a half-bridge switching power supply, or a full-bridge switching power supply. Preferably, the power module 10 provided in this embodiment can be the secondary output circuit of a flyback switching power supply, and the power drive circuit provided in this embodiment can be applied to, for example... Figure 2 The secondary output circuit shown.

[0024] In this embodiment, the current detection module 11 can directly detect the output current of the power module 10, or it can detect an electrical signal that changes accordingly with the output current, which can characterize the magnitude of the output current of the power module 10. For example, the current detection module 11 can detect a voltage signal that changes accordingly with the output current, and determine the magnitude of the output current by detecting the magnitude of the voltage signal. Therefore, the first comparison result can be a comparison between the output current and the reference current, or it can be a comparison between the electrical signal corresponding to the output current and the electrical signal corresponding to the reference current.

[0025] In this embodiment, the voltage divider module 12 can be connected between the power supply voltage terminal Vin and the reference ground terminal of the power supply module 10. When the voltage of the power supply voltage terminal Vin remains unchanged, the voltage of the voltage divider output terminal Vx can be adjusted. That is, the voltage division ratio of the voltage of the voltage divider output terminal Vx in the voltage divider module 12 is adjustable.

[0026] In this embodiment, the adjustment module 13 can receive the first comparison result output by the current detection module 11, and adjust the voltage division ratio of the first voltage at the voltage divider output terminal Vx in the voltage divider module 12 according to the first comparison result. Figure 3As shown, the voltage divider module 12 may include a first voltage divider unit 121 and a second voltage divider unit 122. The first voltage divider unit 121 and the second voltage divider unit 122 are connected in series between the power supply voltage terminal Vin and the reference ground terminal. The common terminal formed by the first voltage divider unit 121 and the second voltage divider unit 122 serves as the voltage divider output terminal Vx. The first voltage divider unit 121 may be connected to the adjustment module 13, and the voltage division ratio of the first voltage divider unit 121 in the voltage divider module 12 can be controlled by the adjustment module 13. The second voltage divider unit 122 may also be connected to the adjustment module 13, and the voltage division ratio of the second voltage divider unit 122 in the voltage divider module 12 can be controlled by the adjustment module 13. The adjustment module 13 can control the voltage division ratio of the first voltage divider unit 121 and / or the second voltage divider unit 122 in the voltage divider module 12.

[0027] Specifically, the adjustment module 13 can increase the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 by increasing the resistance of the second voltage divider unit 122, and / or decrease the resistance of the second voltage divider unit 122 to increase the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12. The adjustment module 13 can decrease the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 by increasing the resistance of the first voltage divider unit 121, and / or decrease the resistance of the second voltage divider unit 122 to decrease the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12. When the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is increased; when the output current is less than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is decreased.

[0028] In this embodiment, the comparison module 14 can compare the voltage of the voltage divider output terminal Vx with the first reference voltage to output a second comparison result. The first reference voltage remains unchanged.

[0029] In this embodiment, the control module 15 can control the output current and power supply voltage according to the second comparison result. It should be noted that when the output current is greater than the reference current, the adjustment module 13 can adjust the voltage divider module 12 to increase the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12, so that the power supply module 10 is in constant current mode. At the same time, when the power supply module 10 is in constant voltage mode, the adjustment module 13 can set the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12. Thus, the driving requirements of constant current mode and constant voltage mode can be met simultaneously.

[0030] Specifically, when the output current is greater than the reference current, the adjustment module 13 can adjust the voltage divider module 12 to increase the voltage division ratio of the output voltage Vx in the voltage divider module 12, thereby reducing the power supply voltage and thus lowering the output current. When the output current is less than the reference current, the adjustment module 13 can adjust the voltage divider module 12 to decrease the voltage division ratio of the output voltage Vx in the voltage divider module 12, thereby increasing the power supply voltage and thus raising the output current. Therefore, through repeated adjustments by the adjustment module 13, the output current can be made to be approximately consistent with the reference current.

[0031] In this embodiment, by employing a power drive circuit including a current detection module 11, a voltage divider module 12, an adjustment module 13, a comparison module 14, and a control module 15, the power supply voltage can be adjusted by changing the voltage division ratio of the voltage divider module 12 without separately setting up current control circuits and voltage control circuits. This allows control of the output current, enabling the output current to reach a preset value. The power drive circuit can meet the driving requirements of constant output current or constant voltage. At the same time, during the control process, there is no need to adjust the equivalent detection current of the reference voltage or sampling resistor, and the DC operating point of the operational amplifier input is not changed, resulting in a smaller comparator response delay or error. This allows impedance matching between the current detection path and the voltage feedback path, improving the stability of the output constant current or constant voltage.

[0032] In some embodiments, the circuit structure of the power supply drive circuit can be as follows: Figure 2 As shown, at this time, the power module 10 is the secondary output circuit of a flyback switching power supply. The power module 10 includes a power transistor K1, which can be connected between the power supply voltage terminal Vin and the supply voltage terminal Vbus. By controlling the on / off state of the power transistor K1, it can be determined whether the power module 10 outputs an output current. Further, the current detection module 11 may include: a detection unit, which is connected to the source and drain terminals of the power transistor K1 of the power module 10 respectively, and detects a second voltage characterizing the magnitude of the output current; and a comparison unit, which is connected to the detection unit, compares the second voltage with a second reference voltage and outputs a first comparison result, whereby the second reference voltage characterizes the magnitude of the reference current.

[0033] In this embodiment, the detection unit can detect the drain-source voltage of the power transistor K1. This drain-source voltage, as a second voltage, can characterize the magnitude of the output current, i.e., converting the output current into a second voltage. The second reference voltage can be regarded as an electrical signal after converting the reference current into a voltage. Specifically, the detection unit can be an operational amplifier, with its positive input terminal connected to the power supply voltage terminal Vin and its negative input terminal connected to the power supply voltage terminal Vbus. The comparison unit can be a first comparator, with its first input terminal connected to the output terminal of the operational amplifier and its second input terminal receiving the second reference voltage. At this time, the signal output by the first comparator can be regarded as the first comparison result, which can reflect the magnitude between the output current and the reference voltage.

[0034] In this embodiment, the output current of the power module 10 is detected by detecting the drain-source voltage of the power transistor K1. This allows the obtained second voltage to be processed and transmitted at a lower impedance, resulting in relatively low sensitivity to noise and improved detection accuracy, without the need for a complex current comparator.

[0035] In some embodiments, the comparison module 14 can be a second comparator. The first terminal of the second comparator is connected to the voltage divider output terminal Vx of the voltage divider module 12. The second terminal of the second comparator receives a second reference voltage. The output terminal of the second comparator is connected to the control module 15. The control module 15 controls the output current and power supply voltage according to the second comparison result output by the output terminal of the second comparator.

[0036] In some embodiments, such as Figure 2 As shown, the power drive circuit may also include a switching transistor K2, which is connected to the power module 10 and the control module 15 respectively. The control module 15 controls the switching transistor K2 according to the second comparison result to control the output current and power supply voltage.

[0037] In this embodiment, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 can be increased. When the control module 15 controls the switch K2 to turn off, the power supply voltage can be controlled to decrease, and the output current will decrease accordingly. When the output current is less than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 can be decreased. When the control module 15 controls the switch K2 to turn off, the power supply voltage can be controlled to decrease, and the output current will decrease accordingly. Therefore, the output current and power supply voltage can be controlled by controlling the state of the switch K2.

[0038] In some embodiments, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is increased.

[0039] In this embodiment, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is increased. Specifically, as follows: Figure 3 As shown, the adjustment module 13 can increase the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 by increasing the resistance value of the second voltage divider unit 122, and / or the adjustment module 13 can increase the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 by decreasing the resistance value of the second voltage divider unit 122.

[0040] In some embodiments, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is gradually increased according to the first preset step size until the output current is less than the reference current.

[0041] In this embodiment, the voltage at the voltage divider output terminal Vx can be increased by adjusting the resistance values ​​of the first voltage divider unit 121 and / or the second voltage divider unit 122 in the voltage divider module 12 according to a first preset step size. This first preset step size can be set based on actual needs.

[0042] In some embodiments, when the output current is less than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is gradually reduced according to the second preset step size until the output current is greater than the reference current. During the gradual increase of the output current, the power supply voltage is always less than the power supply voltage of the power supply module 10 when it is in a constant voltage state.

[0043] In some embodiments, the first preset step size and the second preset step size may be the same.

[0044] In other embodiments, the first preset step size may be different from the second preset step size, and the first preset step size and the second preset step size may be multiples of each other.

[0045] In this embodiment, when the output current is less than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 is reduced. Specifically, as follows: Figure 3 As shown, the adjustment module 13 can reduce the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 by increasing the resistance value of the first voltage divider unit 121, and / or the adjustment module 13 can reduce the voltage division ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12 by decreasing the resistance value of the second voltage divider unit 122.

[0046] It should be noted that in this embodiment, the power supply voltage in the constant current mode of the power supply drive circuit is always lower than the power supply voltage in the constant voltage mode.

[0047] In some embodiments, the resistance value of one of the voltage divider units, the first voltage divider unit 121 and the second voltage divider unit 122, may be adjusted by the adjustment module 13.

[0048] In some embodiments, the voltage divider module 12 includes multiple resistor units and multiple switches. The multiple resistor units are connected to the power supply module 10, and the multiple switches are connected to the adjustment module 13. The adjustment module 13 adjusts the voltage division ratio of the first voltage at the voltage divider output terminal Vx in the voltage divider module 12 by controlling the on / off state of the multiple switches. The common connection terminal formed by two resistor units among the multiple resistor units serves as the voltage divider output terminal Vx.

[0049] In some embodiments, such as Figure 4 As shown, each resistor unit is connected in parallel with a switch.

[0050] In some embodiments, such as Figure 4 As shown, the voltage divider module 12 may include a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8 connected in series, and a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4 connected in parallel with the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6, respectively. The common connection of the fourth resistor R4 and the fifth resistor R5 can be used as the voltage divider output terminal Vx. At this time, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 can form a first voltage divider unit 121, and the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8 can form a second voltage divider unit 122. The on / off state of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 is controlled by the adjustment module 13. Alternatively, the common connection point of the second resistor R2 and the third resistor R3 can be used as the voltage divider output terminal Vx. In this case, the first resistor R1 and the second resistor R2 can form the first voltage divider unit 121, and the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8 can form the second voltage divider unit 122. Alternatively, the common connection point of the sixth resistor R6 and the seventh resistor R7 can be used as the voltage divider output terminal Vx. In this case, the sixth resistor R6 and the seventh resistor R7 can form the first voltage divider unit 121, and the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 can form the second voltage divider unit 122.

[0051] This utility model embodiment also provides a power driver chip, including the power driver circuit provided in any of the above embodiments.

[0052] Since the circuit structure and operation mode of the power drive circuit in the power drive chip of this embodiment are the same as those of the power drive circuit in the previous embodiment, they will not be described again here.

[0053] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A power supply drive circuit, characterized by comprising: include: A current detection module is connected to a power module, which detects the output current of the power module, compares the output current with a reference current, and outputs a first comparison result. A voltage divider module is connected to the power supply module, and the voltage at its voltage divider output terminal represents the power supply voltage of the power supply module. An adjustment module, which is connected to the current detection module, adjusts the voltage division ratio of the first voltage at the voltage divider output terminal in the voltage divider module according to the first comparison result; A comparison module is connected to the voltage divider output terminal, compares the voltage at the voltage divider output terminal with the first reference voltage, and outputs a second comparison result; A control module, connected to the comparison module, controls the output current and the power supply voltage based on the second comparison result.

2. The power supply driving circuit according to claim 1, characterized by The current detection module includes: The detection unit is connected to the source and drain terminals of the power transistor of the power module, respectively, and detects a second voltage that characterizes the magnitude of the output current. The comparison unit is connected to the detection unit, compares the second voltage with the second reference voltage and outputs a first comparison result, wherein the second reference voltage characterizes the magnitude of the reference current.

3. The power supply drive circuit according to claim 1, characterized in that, Also includes: The switching transistor is connected to the power supply module and the control module respectively. The control module controls the switching transistor according to the second comparison result to control the output current and the power supply voltage.

4. The power supply drive circuit according to claim 1, characterized in that, When the output current is greater than the reference current, the voltage at the voltage divider output terminal is increased to increase the voltage division ratio in the voltage divider module.

5. The power drive circuit according to claim 4, characterized in that, When the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage divider output terminal in the voltage divider module is gradually increased according to the first preset step size until the output current is less than the reference current.

6. The power drive circuit according to claim 5, characterized in that, When the output current is less than the reference current, the voltage of the voltage divider output terminal is gradually reduced in the voltage division ratio of the voltage divider module according to the second preset step size until the output current is greater than the reference current. During the process of the output current gradually increasing, the power supply voltage is always less than the power supply voltage of the power supply module when it is in a constant voltage state.

7. The power drive circuit according to claim 1, characterized in that, The voltage divider module includes multiple resistor units and multiple switches. The multiple resistor units are connected to the power supply module, and the multiple switches are connected to the adjustment module. The adjustment module adjusts the voltage division ratio of the first voltage at the voltage divider output terminal in the voltage divider module by controlling the on / off state of the multiple switches. The common connection terminal formed by two of the multiple resistor units serves as the voltage divider output terminal.

8. The power drive circuit according to claim 7, characterized in that, Each of the resistor units is connected in parallel with one of the switches.

9. The power supply drive circuit according to claim 1, characterized in that, The power module is a flyback switching power supply secondary output circuit.

10. A power driver chip, characterized in that, Includes the power drive circuit as described in any one of claims 1 to 9.

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