Power supply driving circuit and chip

Abstract

The embodiment of the invention discloses a power supply driving circuit and a chip, and the circuit comprises a current detection module which is connected with a power supply module, detects the output current of the power supply module, compares the output current with a reference current, and outputs a first comparison result; the voltage division module is connected with the power supply module, and the voltage of the voltage division output end of the voltage division module represents the power supply voltage of the power supply module; the adjusting module is connected with the current detection module and used for adjusting the voltage division proportion of the first voltage of the voltage division output end in the voltage division module according to the first comparison result; the comparison module is connected with the voltage division output end, compares the voltage of the voltage division output end with a first reference voltage and outputs a second comparison result; and the control module is connected with the comparison module and controls the output current and the power supply voltage according to the second comparison result. Through the implementation of the invention, the impedance matching of the current detection path and the voltage feedback path can be realized when the driving requirement of outputting the constant current or the constant voltage is met, and the stability of outputting the constant current or the constant voltage is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a power drive circuit and a chip. Background Art

[0002] In electronic systems such as power management, battery charging, and LED driving, dual-mode control, in both constant current and constant voltage modes, 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 implement mode switching using an operational amplifier comparator circuit. During constant voltage control, the output voltage is compared with a reference voltage, stabilized by a feedback loop. During constant current control, the voltage drop across the sampling resistor is detected and compared with the voltage converted from the current reference to limit the current. However, when the system switches to constant current mode, the reference voltage or the equivalent detection current across the sampling resistor must be adjusted. This changes the DC operating point at the op amp input, resulting in delayed comparator response or increased error. Furthermore, modifying the reference signal can reduce loop stability, induce oscillation, and create an impedance mismatch between the current detection path and the voltage feedback path. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a power drive circuit and chip to solve the above problems. The embodiments of the present invention achieve the above purpose through the following technical solutions.

[0004] An embodiment of the present invention provides a power drive circuit, comprising: a current detection module, which is connected to the power module, 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, which is connected to the power module, and the voltage at its voltage divider output terminal represents the power supply voltage of the power module; a regulation module, which is connected to the current detection module, and 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, which is connected to the voltage divider output terminal, compares the voltage at the voltage divider output terminal with a first reference voltage, and outputs a second comparison result; and a control module, which is connected to the comparison module, and controls the output current and the power supply voltage according to the second comparison result.

[0005] In some embodiments, the current detection module includes: a detection unit, which is respectively connected to the source end and the drain end of the power tube of the power module, and detects a second voltage representing the output current; 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, and the second reference voltage represents the reference current.

[0006] In some embodiments, the power driving circuit further includes: a switch tube, connected to the power module and the control module respectively, and the control module controls the switch tube 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 division output terminal in the voltage division module is increased.

[0008] In some embodiments, when the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage division output terminal in the voltage division module is gradually increased according to a 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 at the voltage divider output end is gradually reduced in the voltage divider module according to a second preset step size until the output current is greater than the reference current. During the process of gradually increasing the output current, the power supply voltage is always less than the power supply voltage when the power supply module is in a constant voltage state.

[0010] In some embodiments, the voltage divider module includes multiple resistance units and multiple switches, the multiple resistance 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 end in the voltage divider module by controlling the on-off state of the multiple switches, and the common end formed by two resistance units among the multiple resistance units serves as the voltage divider output end.

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

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

[0013] An embodiment of the present invention further provides a power driver chip, comprising the power driver circuit provided by any of the above embodiments.

[0014] Compared with the existing technology, through the implementation of the power drive circuit and chip provided in this embodiment, it is possible to adjust the power supply voltage by adjusting the voltage division ratio of the voltage divider module without separately setting up the current control circuit and the voltage control circuit, so as to achieve control of the output current, so that the output current can reach the preset value, and the power drive circuit can meet the driving requirements of outputting constant current or constant voltage. At the same time, during the control process, there is no need to adjust the reference voltage or the equivalent detection current of the sampling resistor, and the DC operating point of the input terminal of the operational amplifier will not be changed, resulting in a small comparator response delay or error. The impedance of the current detection path and the voltage feedback path can be matched, thereby improving the stability of the output constant current or constant voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

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

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

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

[0019] Figure 4 Schematic diagram of the structure of the voltage divider module in the power drive circuit provided in this embodiment. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] The "coupling" or "connection" in the present invention includes both direct connection and indirect connection, such as connection through some active devices, passive devices or electrically conductive media; it may also include connection through other active devices or passive devices on the basis of achieving the same or similar functional purposes as is well known to those skilled in the art, such as connection through circuits or components such as switches and follower circuits.

[0022] See also Figure 1An embodiment of the present invention provides a power drive circuit, comprising 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 module 10, detects the output current of the power 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 module 10, and the voltage at the voltage divider output terminal Vx of the voltage divider module 12 represents the power supply voltage of the power module 10; the adjustment module 13 is connected to the current detection module 11, and adjusts the voltage divider 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 the first reference voltage, and outputs a second comparison result; and the control module 15 is connected to the comparison module 14, and controls the output current and the power supply voltage according to the second comparison result.

[0023] In this embodiment, the power supply module 10 may include a forward switching power supply, a flyback switching power supply, a push-pull switching power supply, a half-bridge switching power supply, or a full-bridge switching power supply. Preferably, the power supply module 10 provided in this embodiment may be a flyback switching power supply secondary output circuit, and the power supply drive circuit provided in this embodiment may be applied to, for example, Figure 2 The secondary output circuit is 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 can produce a corresponding change in the output current, and the electrical signal can represent the magnitude of the output current of the power module 10. For example, the current detection module 11 can detect a voltage signal that produces a corresponding change in 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 magnitude comparison result between the output current and the reference current, or a magnitude comparison result 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 divider ratio 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 of the voltage division output terminal Vx in the voltage division 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 regulating module 13, and the voltage divider ratio of the first voltage divider unit 121 in the voltage divider module 12 may be controlled by the regulating module 13. The second voltage divider unit 122 may be connected to the regulating module 13, and the voltage divider ratio of the second voltage divider unit 122 in the voltage divider module 12 may be controlled by the regulating module 13. The regulating module 13 may control the voltage divider 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 regulating module 13 can increase the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 by increasing the resistance of the second voltage dividing unit 122, and / or the regulating module 13 can increase the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 by reducing the resistance of the second voltage dividing unit 122. The regulating module 13 can decrease the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 by increasing the resistance of the first voltage dividing unit 121, and / or the regulating module 13 can decrease the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 by reducing the resistance of the second voltage dividing unit 122. When the output current is greater than the reference current, the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 is increased; when the output current is less than the reference current, the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 is decreased.

[0028] In this embodiment, the comparison module 14 may compare the voltage at the voltage-dividing output terminal Vx with a first reference voltage to output a second comparison result, wherein the first reference voltage remains unchanged.

[0029] In this embodiment, the control module 15 can control the output current and the power supply voltage based on the second comparison result. It should be noted that when the output current is greater than the reference current, the regulation module 13 can adjust the voltage divider module 12 to increase the voltage divider 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 a constant current mode. At the same time, when the power supply module 10 is in a constant voltage state, the regulation module 13 can set the voltage divider ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12. In this way, the driving requirements of both the constant current mode and the 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 divider ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12, thereby reducing the power supply voltage and, in turn, 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 reduce the voltage divider ratio of the voltage at the voltage divider output terminal Vx in the voltage divider module 12, thereby increasing the power supply voltage and, in turn, increasing the output current. Thus, in the above process, through repeated adjustments by the adjustment module 13, the output current can be made substantially consistent with the reference current.

[0031] In this embodiment, by adopting 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, without separately and independently setting up a current control circuit and a voltage control circuit, the power supply voltage is adjusted by adjusting the voltage divider ratio of the voltage divider module 12 to achieve control of the output current, so that the output current can reach a preset value, and the power drive circuit can also meet the driving requirements of outputting a constant current or a constant voltage. At the same time, during the control process, there is no need to adjust the reference voltage or the equivalent detection current of the sampling resistor, and the DC operating point of the input terminal of the operational amplifier will not be changed, resulting in a smaller comparator response delay or error, and the impedance of the current detection path can be matched with the voltage feedback path, thereby improving the stability of the output constant current or constant voltage.

[0032] In some embodiments, the circuit structure of the power drive circuit can be as follows: Figure 2 As shown, in this case, 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 is possible to determine whether the power module 10 outputs an output current. Furthermore, the current detection module 11 can include: a detection unit, connected to the source and drain terminals of the power transistor K1 of the power module 10, respectively, to detect a second voltage representing the magnitude of the output current; and a comparison unit, connected to the detection unit, to compare the second voltage with a second reference voltage and output a first comparison result, where the second reference voltage represents the magnitude of the reference current.

[0033] In this embodiment, the detection unit can detect the drain-source voltage of the power tube K1. This drain-source voltage, as the second voltage, can represent the magnitude of the output current, that is, convert the output current into the second voltage. The second reference voltage can be regarded as an electrical signal obtained by converting the reference current into a voltage. Specifically, the detection unit can be an operational amplifier, wherein the positive input terminal of the operational amplifier is connected to the power supply voltage terminal Vin, and the negative input terminal of the operational amplifier is connected to the power supply voltage terminal Vbus. The comparison unit can be a first comparator, wherein the first input terminal of the first comparator is connected to the output terminal of the operational amplifier, and the second input terminal of the first comparator receives the second reference voltage. In this case, the signal output by the output terminal of 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 tube K1, so that the obtained second voltage can be processed and transmitted at a lower impedance, is relatively less sensitive to noise, and improves the detection accuracy without setting a complex current comparator.

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

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

[0037] In this embodiment, when the output current is greater than the reference current, the voltage-dividing ratio of the voltage at the voltage-dividing output terminal Vx in the voltage-dividing module 12 can be increased. When the control module 15 controls the switch tube K2 to be turned off, the power supply voltage can be controlled to decrease, and the output current can also decrease accordingly. When the output current is less than the reference current, the voltage-dividing ratio of the voltage at the voltage-dividing output terminal Vx in the voltage-dividing module 12 can be reduced. When the control module 15 controls the switch tube K2 to be turned off, the power supply voltage can be controlled to decrease, and the output current can also decrease accordingly. Therefore, the output current and the power supply voltage can be controlled by controlling the state of the switch tube 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 division output terminal Vx in the voltage division 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 division output terminal Vx in the voltage division module 12 is increased. Specifically, Figure 3 As shown, the regulating module 13 can increase the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 by increasing the resistance value of the second voltage dividing unit 122, and / or the regulating module 13 can increase the voltage dividing ratio of the voltage at the voltage dividing output terminal Vx in the voltage dividing module 12 by reducing the resistance value of the second voltage dividing 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 division output terminal Vx in the voltage division module 12 is gradually increased according to a first preset step size until the output current is less than the reference current.

[0041] In this embodiment, the resistance of the first voltage dividing unit 121 and / or the second voltage dividing unit 122 in the voltage dividing module 12 can be adjusted so that the voltage at the voltage dividing output terminal Vx increases in the voltage dividing ratio of the voltage dividing module 12 according to a first preset step size, and the 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 a second preset step size until the output current is greater than the reference current. During the process of gradually increasing the output current, the power supply voltage is always less than the power supply voltage when the power supply module 10 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 length may be different from the second preset step length, and the first preset step length and the second preset step length may be in a multiple relationship.

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

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

[0047] In some embodiments, the resistance of one of the first voltage dividing unit 121 and the second voltage dividing unit 122 may be adjusted by the adjusting 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 of the voltage divider output terminal Vx in the voltage divider module 12 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 Vx.

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

[0050] In some embodiments, 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 in sequence, 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 point 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 states of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are controlled by the regulation 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] An embodiment of the present invention further provides a power driver chip, comprising the power driver circuit provided by any of the above embodiments.

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

[0053] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A power drive circuit, characterized in that: include: a current detection module connected to the power module, detecting an output current of the power module, comparing the output current with a reference current and outputting a first comparison result; A voltage divider module, connected to the power module, wherein the voltage at the voltage divider output terminal represents the power supply voltage of the power module; a regulating module connected to the current detection module, and regulating a voltage division ratio of the first voltage at the voltage division output end in the voltage division module according to the first comparison result; a comparison module connected to the voltage divider output terminal, comparing the voltage at the voltage divider output terminal with a first reference voltage and outputting a second comparison result; A control module is connected to the comparison module and controls the output current and the power supply voltage according to the second comparison result.

2. The power drive circuit according to claim 1, wherein: The current detection module includes: a detection unit, connected to the source terminal and the drain terminal of the power tube of the power module, respectively, to detect a second voltage representing the magnitude of the output current; A comparison unit is connected to the detection unit, and compares the second voltage with a second reference voltage and outputs a first comparison result, wherein the second reference voltage represents the magnitude of the reference current.

3. The power drive circuit according to claim 1, wherein: Also includes: A switch tube is connected to the power module and the control module respectively, and the control module controls the switch tube according to the second comparison result to control the output current and the power supply voltage.

4. The power drive circuit according to claim 1, wherein: When the output current is greater than the reference current, the voltage division ratio of the voltage at the voltage division output terminal in the voltage division module is increased.

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 division output terminal in the voltage division module is gradually increased according to a 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 division ratio of the voltage at the voltage divider output end in the voltage divider module is gradually reduced according to a second preset step size until the output current is greater than the reference current. During the process of gradually increasing the output current, the power supply voltage is always less than the power supply voltage when the power supply module is in a constant voltage state.

7. The power drive circuit according to claim 1, wherein: The voltage divider module includes multiple resistance units and multiple switches. The multiple resistance 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 end in the voltage divider module by controlling the on-off state of the multiple switches. The common connection end formed by two of the multiple resistance units serves as the voltage divider output end.

8. The power drive circuit according to claim 7, wherein: Each of the resistance units is connected in parallel with one of the switches.

9. The power drive circuit according to claim 1, wherein: The power supply module is a secondary output circuit of a flyback switching power supply.

10. A power driver chip, characterized in that: The invention comprises the power drive circuit according to any one of claims 1 to 9.

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