A control method and circuit for high-voltage linear drive

Abstract

The present invention discloses a control method and circuit for a high-voltage linear drive. A control chip is connected to a plurality of MOS tubes, and the control chip is provided with a current control pin connected to an adjustable resistor. The method comprises: if the current specification of each MOS tube is not a preset minimum specification, determining a target resistance value of the adjustable resistor according to the current specification; adjusting the adjustable resistor to the target resistance value through the current control pin, so that the control chip obtains a first current according to the target resistance value when driving each MOS tube, and drives each MOS tube based on a target drive current generated by the first current and a preset reference current; wherein the preset reference current is equal to the drive current of the MOS tube with a preset minimum specification, the drive current of the drive unit can be designed according to the smaller preset reference current, and the magnitude of the drive current is adjusted based on the current control pin, thereby reducing the cost of EMI optimization.

Description

Technical Field

[0001] The present application relates to the technical field of switching power supplies, and more specifically, to a control method and circuit for a high-voltage linear drive. Background Art

[0002] In conventional switching power supplies, in order to ensure driving speed, the driving current of the driver unit that drives the MOS tube is designed to be relatively large. However, excessive driving current will cause EMI to fail to meet standards. In order to optimize EMI parameters, the conventional practice is to connect a resistor in series with the gate of the MOS tube.

[0003] In high-voltage linear extrapolation MOS applications, a control chip often drives a power range (such as 10W to 50W), and when in use, it will drive 1A or 2A or other specifications of MOS tubes. In order to adapt to different specifications of MOS tubes, the general drive current is designed according to the large-size MOS during the design phase. Because the high-voltage linear system structure has multiple independent MOS tubes, such as Figure 2 The figure shows an application of a commercial product with four independent MOS tubes. To meet EMI standards, multiple resistors and auxiliary devices (such as high-voltage capacitors) need to be added, which is costly.

[0004] Therefore, how to reduce the EMI optimization cost of a high-voltage linear driver including multiple MOS tubes is a technical problem that needs to be solved. Summary of the Invention

[0005] The present invention discloses a control method for a high-voltage linear drive, which is used to solve the technical problem of high cost in the prior art when performing EMI optimization on a high-voltage linear drive including a plurality of MOS tubes.

[0006] The method is applied to a circuit including a control chip and a plurality of MOS tubes connected to the control chip, wherein the control chip is provided with a current control pin connected to an adjustable resistor, and includes:

[0007] If the current specification of each MOS transistor is not a preset minimum specification, determining a target resistance value of the adjustable resistor according to the current specification;

[0008] adjusting the adjustable resistor to the target resistance value through the current control pin, so that the control chip obtains a first current according to the target resistance value when driving each MOS transistor, and drives each MOS transistor based on a target driving current generated by the first current and a preset reference current;

[0009] The preset reference current is equal to the driving current of a MOS tube with a preset minimum specification.

[0010] In some embodiments of the present application, obtaining the first current according to the target resistance value is specifically as follows:

[0011] The first current is obtained according to a calculation result of a preset reference voltage and the target resistance.

[0012] In some embodiments of the present application, the target driving current is generated as follows:

[0013] determining a total current based on a calculation result of the first current and the preset reference current;

[0014] The target driving current is generated according to the product of the total current and a preset coefficient.

[0015] In some embodiments of the present application, if the current specification is the preset minimum specification, the control chip drives each MOS transistor based on the preset reference current when driving each MOS transistor.

[0016] Accordingly, the present invention also proposes a high-voltage linear drive control circuit, the circuit comprising a control chip and a plurality of MOS transistors connected to the control chip, the control chip being provided with a current control pin connected to an adjustable resistor, and the control chip comprising:

[0017] an acquiring unit, configured to acquire a first current according to the adjustable resistor at a target resistance value;

[0018] a generating unit, configured to generate a target driving current according to the first current and a preset reference current;

[0019] a driving unit, configured to drive each of the MOS transistors based on the target driving current;

[0020] The preset reference current is equal to the driving current of the MOS tube with a preset minimum specification, and the target resistance is determined by the current specification of each MOS tube when the current specification is not the preset minimum specification.

[0021] In some embodiments of the present application, the acquiring unit is specifically configured to:

[0022] The first current is obtained according to a calculation result of a preset reference voltage and the target resistance.

[0023] In some embodiments of the present application, a first end of the acquisition unit is connected to the preset reference voltage, a second end of the acquisition unit is connected to the current control pin, and a third end of the acquisition unit is connected to the Vdd pin of the control chip.

[0024] In some embodiments of the present application, the generating unit is an adder, and the generating unit is specifically configured to:

[0025] determining a total current based on a calculation result of the first current and the preset reference current;

[0026] The target driving current is generated according to the product of the total current and a preset coefficient.

[0027] In some embodiments of the present application, the driving unit is further configured to:

[0028] If the current specification is the preset minimum specification, each MOS transistor is driven based on the preset reference current when driving each MOS transistor.

[0029] In some embodiments of the present application, the adjustable resistor is connected between the current control pin and the Gnd pin of the control chip.

[0030] By applying the above technical solution, in a circuit including a control chip and a plurality of MOS transistors connected to the control chip, the control chip is provided with a current control pin connected to an adjustable resistor. If the current specification of each MOS transistor is not a preset minimum specification, a target resistance value of the adjustable resistor is determined based on the current specification. The adjustable resistor is adjusted to the target resistance value via the current control pin, so that the control chip obtains a first current based on the target resistance value when driving each MOS transistor, and drives each MOS transistor based on a target drive current generated by the first current and a preset reference current. The preset reference current is equal to the drive current of the MOS transistor of the preset minimum specification. The drive current of the drive unit can be designed based on a smaller preset reference current, and the magnitude of the drive current is adjusted based on the current control pin, thereby reducing the cost of EMI optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A schematic flow chart of a high-voltage linear drive control method according to an embodiment of the present invention is shown;

[0033] Figure 2 The following is a schematic diagram showing the structure of a control circuit for a high-voltage linear drive in the prior art;

[0034] Figure 3 A schematic structural diagram of a high-voltage linear drive control circuit according to an embodiment of the present invention is shown;

[0035] Figure 4 A schematic diagram of the structure of a control chip in an embodiment of the present invention is shown;

[0036] Figure 5A schematic diagram showing the control principle of a control chip in an embodiment of the present invention is shown;

[0037] Figure 6 A schematic structural diagram of an acquisition unit in an embodiment of the present invention is shown;

[0038] Figure 7 A schematic structural diagram of a generating unit in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] An embodiment of the present application discloses a control method for a high-voltage linear drive, which is applied to a circuit including a control chip and multiple MOS tubes connected to the control chip. The control chip is provided with a current control pin connected to an adjustable resistor. The driving current of the driving unit can be designed according to a smaller preset reference current. For MOS tubes with larger specifications, the driving current can be adjusted through the current control pin, thereby reducing the cost of EMI optimization.

[0041] like Figure 1 As shown, the method includes the following steps:

[0042] Step S101 : If the current specification of each MOS transistor is not a preset minimum specification, determine a target resistance value of the adjustable resistor according to the current specification.

[0043] In this embodiment, the control chip drives a power range (such as 10W to 50W). In the specific application scenario of this application, Figure 3 As shown, the control chip is provided with a current control pin Res, the current control pin Res is connected to the adjustable resistor R4, and the control chip is connected to the MOS tubes M1-M4.

[0044] In this embodiment, the preset reference current is equal to the driving current of the MOS tube with a preset minimum specification. The preset reference current is the designed driving current of the driving unit of the control chip. If the current specification of each MOS tube is not the preset minimum specification, it means that a driving current larger than the preset reference current is required to drive each MOS tube. In this case, the designer needs to adjust the adjustable resistor. The target resistance value of the adjustable resistor can be determined according to the current specification.

[0045] In order to accurately determine the target resistance, in some embodiments of the present application, the target resistance of the adjustable resistor is determined according to the current specification, specifically:

[0046] Querying a first preset relationship table according to current specifications, and determining the target resistance value according to the query result;

[0047] The first preset relationship table represents the corresponding relationship between the specifications of different MOS tubes and the target resistance values.

[0048] In order to reliably perform driving control, in some embodiments of the present application, if the current specification is the preset minimum specification, the control chip drives each MOS tube based on the preset reference current when driving each MOS tube.

[0049] In this embodiment, if the current specification is the preset minimum specification, the preset reference current can meet the driving requirements of each MOS tube, and there is no need to adjust the adjustable resistor. The control chip drives each MOS tube directly based on the preset reference current when driving each MOS tube.

[0050] Step S102: adjusting the adjustable resistor to the target resistance value through the current control pin, so that the control chip obtains a first current according to the target resistance value when driving each MOS transistor, and drives each MOS transistor based on a target driving current generated by the first current and a preset reference current.

[0051] In this embodiment, the adjustable resistor is connected to the current control pin. The designer can adjust the resistance of the adjustable resistor through the current control pin. After the adjustable resistor is adjusted to the target resistance, the control chip obtains a first current according to the target resistance when driving each MOS tube, and then drives each MOS tube based on a target driving current generated by the first current and a preset reference current.

[0052] In order to reliably obtain the first current, in some embodiments of the present application, the first current is obtained according to the target resistance value, specifically:

[0053] The control chip obtains the first current according to a calculation result of a preset reference voltage and the target resistance value.

[0054] In this embodiment, a preset reference voltage is set in the control chip, and a calculation result of the preset reference voltage and the target resistance value is obtained, and the calculation result is used as the first current.

[0055] Optionally, in some embodiments of the present application, the calculation result of the preset reference voltage and the target resistance is the ratio of the preset reference voltage to the target resistance, and the preset reference voltage is 1V.

[0056] Those skilled in the art may set different preset reference voltages according to actual needs, which does not affect the protection scope of this application.

[0057] In order to accurately generate the target driving current, in some embodiments of the present application, the target driving current is generated as follows:

[0058] determining a total current based on a calculation result of the first current and the preset reference current;

[0059] The target driving current is generated according to the product of the total current and a preset coefficient.

[0060] In this embodiment, the total current is first obtained according to the calculation result of the first current and the preset reference current, and then the total current is multiplied by the preset coefficient to obtain the target driving current.

[0061] Optionally, in some embodiments of the present application, the calculation result of the first current and the preset reference current is the sum of the first current and the preset reference current.

[0062] Optionally, in some embodiments of the present application, the preset reference current is 3.2uA and the preset coefficient is 7 / 4.

[0063] Those skilled in the art may set different preset coefficients and different preset reference currents according to actual needs, which does not affect the protection scope of this application.

[0064] By applying the above technical solution, in a circuit including a control chip and a plurality of MOS transistors connected to the control chip, the control chip is provided with a current control pin connected to an adjustable resistor. If the current specification of each MOS transistor is not a preset minimum specification, a target resistance value of the adjustable resistor is determined based on the current specification. The adjustable resistor is adjusted to the target resistance value via the current control pin, so that the control chip obtains a first current based on the target resistance value when driving each MOS transistor, and drives each MOS transistor based on a target drive current generated by the first current and a preset reference current. The preset reference current is equal to the drive current of the MOS transistor of the preset minimum specification. The drive current of the drive unit can be designed based on a smaller preset reference current, and the magnitude of the drive current is adjusted based on the current control pin, thereby reducing the cost of EMI optimization.

[0065] The embodiment of the present application also provides a control circuit for a high-voltage linear drive, which includes a control chip and a plurality of MOS tubes connected to the control chip. The control chip is provided with a current control pin connected to an adjustable resistor, such as Figure 4 As shown, the control chip includes:

[0066] An acquisition unit 10 is configured to acquire a first current according to an adjustable resistor at a target resistance value;

[0067] A generating unit 20, configured to generate a target driving current according to the first current and a preset reference current;

[0068] A driving unit 30, configured to drive each MOS transistor based on a target driving current;

[0069] The preset reference current is equal to the driving current of the MOS tube with a preset minimum specification, and the target resistance is determined by the current specification of each MOS tube when the current specification is not the preset minimum specification.

[0070] It is understandable that if Figure 5 As shown, the control chip also includes units such as Vdd, reference voltage, PWM, analog operation, VS / CS operation, digital operation, multiplier, reference voltage and current sampling. The specific working process of each unit is the existing technology and will not be repeated here.

[0071] In the specific application scenario of this application, the acquisition unit 10 is specifically used to:

[0072] A first current is obtained according to a calculation result of a preset reference voltage and a target resistance value.

[0073] In order to ensure the reliability of the acquisition unit 10, in some embodiments of the present application, the first end of the acquisition unit 10 is connected to a preset reference voltage, the second end of the acquisition unit 10 is connected to a current control pin, and the third end of the acquisition unit 10 is connected to the Vdd pin of the control chip.

[0074] Optionally, in some embodiments of the present application, such as Figure 6 As shown, the acquisition unit 10 includes an operational amplifier op and a transistor M5. The first input terminal of the operational amplifier op is the first terminal of the acquisition unit 10 (connected to the preset reference voltage V1), the second input terminal of the operational amplifier op and the source of the transistor M5 are commonly connected to the second terminal of the acquisition unit 10 (connected to the current control pin Res), the output terminal of the operational amplifier op is connected to the gate of the transistor M5, and the drain of the transistor M5 is connected to the third terminal of the acquisition unit 10 (connected to the Vdd pin). The first current I1 is generated at the drain of the transistor M5. Specifically, I1=V1 / R4.

[0075] It should be noted that the solution in the above embodiment is only a specific implementation solution proposed in this application. Those skilled in the art may also use other components to form an acquisition unit to obtain the first current, which does not affect the protection scope of this application.

[0076] In the specific application scenario of the present application, the generating unit 20 is an adder, and the generating unit 20 is specifically used to:

[0077] Determining a total current based on a calculation result of the first current and a preset reference current;

[0078] The target driving current is generated according to the product of the total current and a preset coefficient.

[0079] like Figure 7 As shown, the generating unit 20 is an adder, and the first current I1 and the preset reference current I0 are input into the adder to obtain the target driving current.

[0080] Specifically, the target driving current I driver =(I1+I0)*k, where k is a preset coefficient.

[0081] It should be noted that the solution in the above embodiment is only a specific implementation solution proposed in this application. Those skilled in the art may also use other elements to form a generation unit to generate the target driving current, which does not affect the protection scope of this application.

[0082] In the specific application scenario of this application, the drive unit 30 is also used to:

[0083] If the current specification is the preset minimum specification, each MOS transistor is driven based on a preset reference current when driving each MOS transistor.

[0084] In the specific application scenario of this application, such as Figure 3 As shown, the control chip further includes a Gnd pin, and the adjustable resistor R4 is connected between the current control pin Res and the Gnd pin.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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. However, these modifications or replacements 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 the present application.

Claims

1. A control method for a high-voltage linear drive, characterized in that: Applied to a circuit including a control chip and a plurality of MOS transistors connected to the control chip, wherein the control chip is provided with a current control pin connected to an adjustable resistor, the method includes: If the current specification of each MOS transistor is not a preset minimum specification, determining a target resistance value of the adjustable resistor according to the current specification; adjusting the adjustable resistor to the target resistance value through the current control pin, so that the control chip obtains a first current according to the target resistance value when driving each MOS transistor, and drives each MOS transistor based on a target driving current generated by the first current and a preset reference current; The preset reference current is equal to the driving current of a MOS tube with a preset minimum specification; The target driving current generation process is specifically as follows: determining a total current based on a calculation result of the first current and the preset reference current; The target driving current is generated according to the product of the total current and a preset coefficient.

2. The method according to claim 1, wherein The first current is obtained according to the target resistance value, specifically: The first current is obtained according to a calculation result of a preset reference voltage and the target resistance.

3. The method according to claim 1, wherein If the current specification is the preset minimum specification, the control chip drives each MOS transistor based on the preset reference current when driving each MOS transistor.

4. A control circuit for a high-voltage linear drive, characterized in that: The circuit includes a control chip and a plurality of MOS tubes connected to the control chip. The control chip is provided with a current control pin connected to an adjustable resistor. The control chip includes: an acquiring unit, configured to acquire a first current according to the adjustable resistor at a target resistance value; a generating unit, configured to generate a target driving current according to the first current and a preset reference current; a driving unit, configured to drive each of the MOS transistors based on the target driving current; The preset reference current is equal to the driving current of the MOS tube of the preset minimum specification, and the target resistance value is determined by the current specification of each MOS tube when the current specification is not the preset minimum specification; The generating unit is an adder, and the generating unit is specifically configured to: determining a total current based on a calculation result of the first current and the preset reference current; The target driving current is generated according to the product of the total current and a preset coefficient.

5. The circuit according to claim 4, wherein: The acquisition unit is specifically configured to: The first current is obtained according to a calculation result of a preset reference voltage and the target resistance.

6. The circuit according to claim 5, wherein: A first end of the acquisition unit is connected to the preset reference voltage, a second end of the acquisition unit is connected to the current control pin, and a third end of the acquisition unit is connected to the Vdd pin of the control chip.

7. The circuit according to claim 4, wherein: The drive unit is further configured to: If the current specification is the preset minimum specification, each MOS transistor is driven based on the preset reference current when driving each MOS transistor.

8. The circuit according to claim 4, wherein: The adjustable resistor is connected between the current control pin and the Gnd pin of the control chip.

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