Hysteresis current mode controller and method of controlling the same

Abstract

The application provides a hysteresis current mode controller and a control method thereof. The controller comprises at least a comparator and a hysteresis voltage generating circuit. The non-inverting input terminal of the comparator is connected to the hysteresis voltage, the inverting input terminal is connected to a detection voltage, and the output terminal generates a driving signal. The hysteresis voltage generating circuit is used to switch the output between the upper limit value and the lower limit value of the hysteresis voltage according to the driving signal. The lower limit value of the hysteresis voltage is a first fixed value. The upper limit value of the hysteresis voltage changes with the dimming voltage when the dimming voltage is less than a first reference voltage, and is a second fixed value when the dimming voltage is greater than the first reference voltage. The second fixed value is related to the first reference voltage. The hysteresis current mode controller and the control method thereof provided by the application solve the problem that the width of the hysteresis voltage of the existing hysteresis current mode controller cannot be adjusted.

Description

Technical Field

[0001] This invention relates to the field of LED lighting, and in particular to a hysteresis current-mode controller and its control method. Background Technology

[0002] Based on the light-emitting principle and characteristics of LEDs, constant current sources are selected to drive LED chips. Constant current sources are generally divided into linear constant current sources and switching-mode constant current sources. Switching-mode constant current sources stand out due to their high efficiency and small size. Among them, the Buck topology is widely used in high-power LED driving applications because of its simple structure and strong versatility. Switching-mode constant current sources are generally divided into open-loop control and closed-loop control. Closed-loop control is widely used due to its high steady-state accuracy and strong disturbance rejection capability. Hysteresis current-mode control, in particular, has a broad market space in low-cost applications because of its high loop bandwidth and the absence of a compensation network.

[0003] Existing Buck circuits and their control circuits with hysteresis current control mode, such as Figure 1 and Figure 2 As shown, when the dimming voltage Vdim is greater than the reference voltage Vref, the dimming current Idim is equal to 0. At this time, the inductor current is converted into a proportional voltage signal Vcs through resistors Rcs, R1, and transconductance Gm1. Internally, an upper limit Vcsh and a lower limit Vcsl for the hysteresis voltage are set. When the voltage signal Vcs rises to the upper limit Vcsh, the drive signal Drv output by comparator CMP jumps low, the power transistor Mos is turned off, and switch S1 switches to position 2. When the voltage signal Vcs falls to the lower limit Vcsl, the drive signal Drv output by comparator CMP jumps high, the power transistor Mos is turned on, and switch S1 switches to position 1. This cycle repeats, and the average value Vavg of the voltage signal Vcs is controlled as (Vcsh + Vcsl) / 2 (as shown in the diagram). Figure 3 As shown in the figure, the average value of the inductor current is also proportionally controlled to IL.

[0004] When the dimming voltage Vdim is less than the reference voltage Vref, the dimming current Idim is not equal to 0. At this time, the voltage across resistor R1 is Vcs + Idim * R1. According to the previous description, the average voltage across resistor R1 is still equal to (Vcsh + Vcsl) / 2. Therefore, the average value of the voltage signal Vcs will decrease, and the average value of the inductor current will also decrease accordingly, thus achieving linear regulation of the output current.

[0005] In the control circuit of the existing Buck circuit with hysteresis current control mode, the upper limit value Vcsh and the lower limit value Vcsl of the hysteresis voltage are both composed of fixed voltage sources, and the hysteresis voltage width ΔV (i.e., the difference between the upper and lower limits) is not adjustable (e.g., ...). Figure 4 As shown, there are limitations in applications with a wide output current range.

[0006] Moreover, under the existing dimming method, the lower limit of the output current is when the inductor current is in the critical mode. At this time, the voltage signal Vcs is equal to (Vcsh-Vcsl) / 2, that is, the minimum output current is k*(Vcsh-Vcsl) / 2, where k=1 / (R1*Gm1*Rcs), and the maximum output current is k*(Vcsh+Vcsl) / 2. The ratio of the minimum output current to the maximum output current is (Vcsh-Vcsl) / (Vcsh+Vcsl). Since the ripple factor is usually designed to be 15%, the minimum output current can only reach 15%, which cannot meet the requirement of a lower output current. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a hysteresis current mode controller and its control method to solve the problem that the hysteresis voltage width is not adjustable in existing hysteresis current mode controllers.

[0008] To achieve the above and other related objectives, the present invention provides a hysteresis current-mode controller, the controller comprising at least: a comparator and a hysteresis voltage generation circuit, wherein the non-inverting input terminal of the comparator is connected to a hysteresis voltage, the inverting input terminal is connected to a detection voltage, and the output terminal generates a drive signal; the hysteresis voltage generation circuit is used to switch the output between an upper limit and a lower limit of the hysteresis voltage according to the drive signal; wherein the lower limit of the hysteresis voltage is a first fixed value, the upper limit of the hysteresis voltage follows the dimming voltage when the dimming voltage is less than a first reference voltage, and is a second fixed value when the dimming voltage is greater than the first reference voltage, and the second fixed value is related to the first reference voltage.

[0009] Optionally, the controller further includes: a first transconductance device, a second transconductance device, and a first resistor, wherein the two input terminals of the first transconductance device are connected to the two ends of the detection resistor, the output terminal is grounded through the first resistor, and outputs the detection voltage; the non-inverting input terminal of the second transconductance device is connected to the second reference voltage, the inverting input terminal is connected to the dimming voltage, and the output terminal is connected to the output terminal of the first transconductance device.

[0010] Optionally, the hysteresis voltage generation circuit includes: a voltage width setting module, a voltage-to-current conversion module, and a hysteresis voltage generation module, wherein the voltage width setting module is used to output a voltage signal related to the dimming voltage or the first reference voltage according to the magnitude relationship between the dimming voltage and the first reference voltage; the voltage-to-current conversion module is used to convert the voltage signal output by the voltage width setting module into a current signal and output it; the hysteresis voltage generation module is used to generate and output a lower limit value of the hysteresis voltage based on a fixed voltage source when the driving signal is low, and to generate and output an upper limit value of the hysteresis voltage based at least on the current signal output by the voltage-to-current conversion module when the driving signal is high.

[0011] Optionally, the voltage width setting module is used to output the first reference voltage when the dimming voltage is greater than the first reference voltage, and to output the dimming voltage when the dimming voltage is less than the first reference voltage.

[0012] Optionally, the voltage width setting module is implemented using a linear voltage regulator.

[0013] Optionally, the linear voltage regulator includes: a first amplifier, a first MOSFET, and a first capacitor, wherein the non-inverting input terminal of the first amplifier is connected to the first reference voltage, the inverting input terminal is connected to the source terminal of the first MOSFET, and the output terminal is connected to the gate terminal of the first MOSFET; the drain terminal of the first MOSFET is connected to the dimming voltage, and the source terminal is grounded through the first capacitor and serves as the output terminal of the linear voltage regulator.

[0014] Optionally, the voltage-to-current conversion module includes: a second amplifier, a second MOSFET, and a second resistor, wherein the non-inverting input terminal of the second amplifier is connected to the voltage signal output by the voltage width setting module, the inverting input terminal is connected to the source terminal of the second MOSFET, and the output terminal is connected to the gate terminal of the second MOSFET; the drain terminal of the second MOSFET serves as the output terminal of the voltage-to-current conversion module, and the source terminal is grounded through the second resistor.

[0015] Optionally, when the drive signal is high, the hysteresis voltage generation module generates and outputs the upper limit value of the hysteresis voltage based on the current signal output by the voltage-to-current conversion module and the fixed voltage source.

[0016] Optionally, the hysteresis voltage generation module includes: a current mirror unit, an input selection unit, a fixed voltage source, and an adder. The current mirror unit mirrors the current signal output by the voltage-to-current conversion module. The input selection unit generates a zero-voltage output when the drive signal is low, and generates a non-zero voltage output based on the mirrored current output by the current mirror unit when the drive signal is high. The first input terminal of the adder is connected to the voltage signal output by the input selection unit, the second input terminal is connected to the fixed voltage source, and the output terminal serves as the output terminal of the hysteresis voltage generation module.

[0017] Optionally, the input selection unit includes: a third MOSFET, a third resistor, and an inverter, wherein the gate terminal of the third MOSFET is connected to the drive signal through the inverter, the drain terminal is connected to the mirrored current output by the current mirror unit, and the source terminal is grounded; the first terminal of the third resistor is connected to the drain terminal of the third MOSFET, and the second terminal is grounded.

[0018] The present invention also provides a hysteresis current-mode control method, the control method comprising: detecting an inductor current and generating a detection voltage; comparing the detection voltage and a hysteresis voltage, and generating a drive signal based on the comparison result, wherein an upper limit and a lower limit of the hysteresis voltage are controlled by the drive signal to switch back and forth; wherein the lower limit of the hysteresis voltage is a first fixed value, the upper limit of the hysteresis voltage follows the dimming voltage when the dimming voltage is less than a reference voltage, and is a second fixed value when the dimming voltage is greater than the reference voltage, and the second fixed value is related to the reference voltage.

[0019] Optionally, the method for generating the hysteresis voltage includes: when the driving signal is low, generating a lower limit value of the hysteresis voltage based on a fixed voltage source; when the driving signal is high, if the dimming voltage is greater than the reference voltage, generating an upper limit value of the hysteresis voltage based on the reference voltage and the fixed voltage source; if the dimming voltage is less than the reference voltage, generating an upper limit value of the hysteresis voltage based on the dimming voltage and the fixed voltage source.

[0020] As described above, the hysteresis current-mode controller and its control method of the present invention, through the design of the hysteresis voltage generation circuit, utilize the linear and nonlinear regions of the linear voltage source to set the hysteresis voltage width, thereby achieving adjustable hysteresis voltage width. This enables segmented linear dimming (i.e., when the dimming voltage is greater than the first reference voltage, the output current is changed by DC bias injection; when the dimming voltage is less than the first reference voltage, the output current is changed by the simultaneous action of DC bias injection and hysteresis voltage regulation), thus broadening the range of output current and making it suitable for more applications. Attached Figure Description

[0021] Figure 1 The diagram shown is a schematic of an existing hysteresis current-mode Buck circuit.

[0022] Figure 2 Displayed as Figure 1 The control circuit of the Buck circuit shown.

[0023] Figure 3 Displayed as Figure 2 The waveforms of the voltage signal Vcs and the upper and lower limits of the hysteresis voltage Vcsh and Vcsl in the control circuit shown are displayed.

[0024] Figure 4 Displayed as Figure 2 The waveform diagram of the hysteresis voltage width in the control circuit shown.

[0025] Figure 5 The diagram shown is a schematic of the hysteresis current mode controller of the present invention.

[0026] Figure 6 The diagram shown is a schematic of the hysteresis voltage generation circuit of the present invention.

[0027] Figure 7 The diagram shows the waveform of the hysteresis voltage width in the hysteresis current-mode controller of this invention.

[0028] Component designation explanation

[0029] 100 Hysteresis Voltage Generation Circuit

[0030] 110 Voltage Width Setting Module

[0031] 120 Voltage-to-Current Conversion Module

[0032] 130 Hysteresis Voltage Generation Module

[0033] 131 Current Mirror Unit

[0034] 132 Input Selection Unit Detailed Implementation

[0035] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0036] Please see Figures 5 to 7It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation, the shape, quantity and proportion of each component in the actual implementation can be arbitrarily changed, and the layout of the components may also be more complex.

[0037] like Figure 5 and Figure 6 As shown, this embodiment provides a hysteresis current-mode controller, which includes at least a comparator CMP and a hysteresis voltage generation circuit 100. Further, the controller also includes a first transconductance device Gm1, a second transconductance device Gm2, and a first resistor R1.

[0038] The first transconductance device Gm1 has two input terminals connected to the two ends of the detection resistor Rcs, and its output terminal is grounded through the first resistor R1, outputting the detection voltage Vcs. The second transconductance device Gm2 has its non-inverting input terminal connected to the second reference voltage Vref2, its inverting input terminal connected to the dimming voltage Vdim, and its output terminal connected to the output terminal of the first transconductance device Gm1. Optionally, both the first transconductance device Gm1 and the second transconductance device Gm2 are transconductance amplifiers.

[0039] In this embodiment, the inductor current is converted into a detection voltage Vcs through the detection resistor Rcs, the first transconductance device Gm1 and the first resistor R1, and when the dimming voltage Vdim is less than the second reference voltage Vref2, the output current is linearly adjusted by utilizing the dimming current Idim output by the second transconductance device Gm2, which is not 0.

[0040] The comparator CMP has a hysteresis voltage Vhys connected to its non-inverting input and a detection voltage Vcs connected to its inverting input, and generates a drive signal Drv at its output.

[0041] In this embodiment, when the hysteresis voltage Vhys is greater than the detection voltage Vcs, the comparator CMP generates a high-level drive signal; conversely, when the hysteresis voltage Vhys is less than the detection voltage Vcs, the comparator CMP generates a low-level drive signal.

[0042] The hysteresis voltage generating circuit 100 is used to switch the output between an upper limit value Vcsh and a lower limit value Vcsl of the hysteresis voltage according to the driving signal Drv; wherein, the lower limit value Vcsl of the hysteresis voltage is a first fixed value, the upper limit value Vcsh of the hysteresis voltage follows the dimming voltage Vdim when the dimming voltage Vdim is less than the first reference voltage Vref1, and is a second fixed value when the dimming voltage Vdim is greater than the first reference voltage Vref1, and the second fixed value is related to the first reference voltage Vref1.

[0043] Specifically, the hysteresis voltage generation circuit 100 includes: a voltage width setting module 110, a voltage-to-current conversion module 120, and a hysteresis voltage generation module 130.

[0044] The voltage width setting module 110 is used to output a voltage signal related to the dimming voltage Vdim or the first reference voltage Vref1 according to the magnitude relationship between the dimming voltage Vdim and the first reference voltage Vref1.

[0045] More specifically, the voltage width setting module 110 is used to output the first reference voltage Vref1 when the dimming voltage Vdim is greater than the first reference voltage Vref1; and to output the dimming voltage Vdim when the dimming voltage Vdim is less than the first reference voltage Vref1. Optionally, the voltage width setting module 110 is implemented using a linear regulated source.

[0046] As an example, the linear voltage regulator includes: a first amplifier AMP1, a first MOSFET M1, and a first capacitor C1; wherein, the non-inverting input terminal of the first amplifier AMP1 is connected to the first reference voltage Vref1, the inverting input terminal is connected to the source terminal of the first MOSFET M1, and the output terminal is connected to the gate terminal of the first MOSFET M1; the drain terminal of the first MOSFET M1 is connected to the dimming voltage Vdim, and the source terminal is grounded through the first capacitor C1, serving as the output terminal of the linear voltage regulator.

[0047] In this embodiment, when the dimming voltage Vdim is greater than the first reference voltage Vref1, the loop regulation of the linear voltage regulator enters the linear region. At this time, the output voltage of the linear voltage regulator, that is, the source voltage of the first MOS transistor M1, Vc1 = Vref1; when the dimming voltage Vdim is less than the first reference voltage Vref1, the loop regulation of the linear voltage regulator enters the nonlinear region. At this time, the first MOS transistor M1 is in a fully conducting state, and the output voltage of the linear voltage regulator, that is, the source voltage of the first MOS transistor M1, Vc1 = Vdim.

[0048] The voltage-to-current conversion module 120 is used to convert the voltage signal Vc1 output by the voltage width setting module 110 into a current signal and output it.

[0049] As an example, the voltage-to-current conversion module 120 includes: a second amplifier AMP2, a second MOSFET M2, and a second resistor R2; wherein, the non-inverting input terminal of the second amplifier AMP2 is connected to the voltage signal Vc1 output by the voltage width setting module 110, the inverting input terminal is connected to the source terminal of the second MOSFET M2, and the output terminal is connected to the gate terminal of the second MOSFET M2; the drain terminal of the second MOSFET M2 serves as the output terminal of the voltage-to-current conversion module 120, and the source terminal is grounded through the second resistor R2.

[0050] In this embodiment, the voltage-to-current conversion module 120 uses the "virtual short and virtual open" of the second amplifier AMP2 to limit the source voltage of the second MOS transistor M2 to Vc1, and uses the second resistor R2 to convert the voltage into current, so that the current flowing through the drain of the second MOS transistor M2 is equal to Vc1 / R2.

[0051] The hysteresis voltage generation module 130 is used to generate and output a lower limit value Vcsl of the hysteresis voltage based on a fixed voltage source V1 when the drive signal Drv is low; and to generate and output an upper limit value Vcsh of the hysteresis voltage based at least on the current signal output by the voltage-to-current conversion module 120 when the drive signal Drv is high.

[0052] More specifically, when the drive signal Drv is low, the hysteresis voltage generation module 130 generates and outputs the lower limit value Vcsl of the hysteresis voltage based on the fixed voltage source V1; when the drive signal Drv is high, it generates and outputs the upper limit value Vcsh of the hysteresis voltage based on the current signal output by the voltage-to-current conversion module 120 and the fixed voltage source V1.

[0053] As an example, the hysteresis voltage generation module 130 includes: a current mirror unit 131, an input selection unit 132, a fixed voltage source V1, and an adder ADD.

[0054] The current mirroring unit 131 is used to mirror the current signal output by the voltage-to-current conversion module 120. The current mirroring unit 131 includes a first mirror MOSFET Mm1 and a second mirror MOSFET Mm2. The gate terminal of the first mirror MOSFET Mm1 is connected to its drain terminal and the gate terminal of the second mirror MOSFET Mm2. Its source terminal is connected to the power supply voltage Vcc, and its drain terminal is connected to the current signal output by the voltage-to-current conversion module 120. The source terminal of the second mirror MOSFET Mm2 is connected to the power supply voltage Vcc, and its drain terminal serves as the output terminal of the current mirroring unit 131 to generate a mirrored current.

[0055] In this embodiment, the first mirror MOSFET Mm1 and the second mirror MOSFET Mm2 constitute a current mirror structure, mirroring the drain current of the first mirror MOSFET Mm1 to the drain of the second mirror MOSFET Mm2. In this example, the magnification factor of the current mirror structure is 1. Of course, in other examples, this magnification factor may not be 1, which does not affect this embodiment.

[0056] The input selection unit 132 is used to generate a zero-voltage output when the drive signal Drv is low, and to generate a non-zero voltage output based on the mirrored current output by the current mirror unit 131 when the drive signal Drv is high. The input selection unit 132 includes a third MOSFET M3 and a third resistor R3; the gate of the third MOSFET M3 is connected to the inverted signal of the drive signal Drv, the drain is connected to the mirrored current output by the current mirror unit 131, and the source is grounded; the first end of the third resistor R3 is connected to the drain of the third MOSFET M3, and the second end is grounded. Further, the input selection unit 132 also includes an inverter (not shown in the figure), whose input end is connected to the drive signal Drv, and whose output end is connected to the gate of the third MOSFET M3.

[0057] In this embodiment, when the drive signal Drv is low, its inverting signal is high. At this time, the third MOS transistor M3 is fully turned on, and the mirrored current output by the current mirror unit 131 flows into ground through the channel of the third MOS transistor M3. The drain voltage of the third MOS transistor M3 is 0, and the voltage output by the input selection unit 132 is 0. When the drive signal Drv is high, its inverting signal is low. At this time, the third MOS transistor M3 is completely turned off, and the mirrored current output by the current mirror unit 131 flows into the third resistor R3, generating a voltage drop across the third resistor R3. The voltage output by the input selection unit 132 is (Vc1 / R2)*R3.

[0058] The first input terminal of the adder ADD is connected to the voltage signal output by the input selection unit 132, the second input terminal is connected to the fixed voltage source V1, and the output terminal serves as the output terminal of the hysteresis voltage generation module 130 to generate the hysteresis voltage Vhys.

[0059] In this embodiment, when the voltage output by the input selection unit 132 is 0, the output of the adder ADD is the sum of 0 and the fixed voltage source V1, i.e., V1. At this time, the hysteresis voltage Vhys = V1 output by the hysteresis voltage generation circuit 100 is used as the lower limit value Vcsl of the hysteresis voltage. When the voltage output by the input selection unit 132 is (Vc1 / R2)*R3, the output of the adder ADD is the sum of (Vc1 / R2)*R3 and the fixed voltage source V1, i.e., (Vc1 / R2)*R3+V1. At this time, the hysteresis voltage Vhys = (Vc1 / R2)*R3+V1 output by the hysteresis voltage generation circuit 100 is used as the upper limit value Vcsh of the hysteresis voltage.

[0060] In this embodiment, the hysteresis voltage generating circuit 100 outputs a hysteresis voltage Vhys with a lower limit of Vcsl = V1 and an upper limit of Vcsh = (Vc1 / R2)*R3 + V1. From the expression for the upper limit Vcsh, it can be seen that when the dimming voltage Vdim is greater than the first reference voltage Vref1, the hysteresis voltage width ΔV is determined by the value of the first reference voltage Vref1. When the dimming voltage Vdim is less than the first reference voltage Vref1, the hysteresis voltage width ΔV decreases linearly as the dimming voltage Vdim decreases (e.g., ...). Figure 7 (As shown). For the controller described in this embodiment, the ratio of the minimum output current to the maximum output current is (Vdim / R2)*R3 / [(Vref1 / R2)*R3+2*V1]. When the output current is low, the hysteresis voltage width ΔV can be reduced to meet the requirement of a smaller output current.

[0061] Accordingly, this embodiment also provides a hysteresis current-mode control method, which can be based on Figure 5 and Figure 6 The control method, implemented using a hysteresis current-mode controller, includes:

[0062] 1) Detect inductor current and generate detection voltage.

[0063] Specifically, it can be achieved through, for example Figure 5 The detection resistor Rcs, the first transconductance device Gm1, and the first resistor R1 shown are used to detect the inductor current and generate a detection voltage Vcs; of course, other methods that can detect the inductor current and generate a detection voltage are also applicable to this embodiment.

[0064] 2) Compare the detection voltage Vcs and the hysteresis voltage Vhys, and generate a drive signal Drv based on the comparison result. The upper limit value Vcsh and the lower limit value Vcsl of the hysteresis voltage Vhys are controlled by the drive signal Drv and switch back and forth. The lower limit value Vcsl of the hysteresis voltage is a first fixed value. The upper limit value Vcsh of the hysteresis voltage follows the dimming voltage Vdim when the dimming voltage Vdim is less than the reference voltage Vref. When the dimming voltage Vdim is greater than the reference voltage Vref, it is a second fixed value, and the second fixed value is related to the reference voltage Vref.

[0065] Specifically, a comparator is used to compare the detection voltage Vcs and the hysteresis voltage Vhys, and a high-level drive signal is generated when the detection voltage Vcs is less than the hysteresis voltage Vhys, and a low-level drive signal is generated when the detection voltage is greater than the hysteresis voltage Vhys.

[0066] Specifically, the method for generating the hysteresis voltage Vhys includes: when the drive signal Drv is low, generating a lower limit value Vcsl of the hysteresis voltage Vhys based on a fixed voltage source; when the drive signal Drv is high, generating an upper limit value Vcsh of the hysteresis voltage Vhys based at least on the dimming voltage Vdim or the reference voltage Vref, according to the relationship between the dimming voltage Vdim and the reference voltage Vref.

[0067] More specifically, the method for generating the upper limit value of the hysteresis voltage Vcsh includes: when the dimming voltage Vdim is greater than the reference voltage Vref, generating the upper limit value of the hysteresis voltage Vhys Vcsh based on the reference voltage Vref and the fixed voltage source, such that the hysteresis voltage width ΔV is determined by the value of the reference voltage Vref; when the dimming voltage Vdim is less than the reference voltage Vref, generating the upper limit value of the hysteresis voltage Vhys Vcsh based on the dimming voltage Vdim and the fixed voltage source, such that the hysteresis voltage width ΔV decreases linearly as the dimming voltage Vdim decreases.

[0068] In summary, the hysteresis current-mode controller and its control method of the present invention, through the design of the hysteresis voltage generation circuit, utilizes the linear and nonlinear regions of the linear voltage source to set the hysteresis voltage width, thereby achieving adjustable hysteresis voltage width. This enables segmented linear dimming (i.e., when the dimming voltage is greater than the first reference voltage, the output current is changed by DC bias injection; when the dimming voltage is less than the first reference voltage, the output current is changed by the simultaneous action of DC bias injection and hysteresis voltage regulation), thus widening the range of output current and making it suitable for more applications. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial applicability.

[0069] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A hysteresis current-mode controller, characterized in that, The controller includes at least: a comparator and a hysteresis voltage generation circuit, wherein... The comparator is connected to a hysteresis voltage at its non-inverting input, a detection voltage at its inverting input, and a drive signal at its output. The hysteresis voltage generating circuit is used to switch the output between an upper limit and a lower limit of the hysteresis voltage according to the driving signal; wherein, the lower limit of the hysteresis voltage is a first fixed value, the upper limit of the hysteresis voltage follows the dimming voltage when the dimming voltage is less than the first reference voltage, and is a second fixed value when the dimming voltage is greater than the first reference voltage, and the second fixed value is related to the first reference voltage; The hysteresis voltage generation circuit includes: a voltage width setting module, a voltage-to-current conversion module, and a hysteresis voltage generation module, wherein... The voltage width setting module is used to output a voltage signal related to the dimming voltage or the first reference voltage according to the magnitude relationship between the dimming voltage and the first reference voltage; The voltage-to-current conversion module is used to convert the voltage signal output by the voltage width setting module into a current signal and output it. The hysteresis voltage generation module is used to generate and output a lower limit value of the hysteresis voltage based on a fixed voltage source when the drive signal is low, and to generate and output an upper limit value of the hysteresis voltage based at least on the current signal output by the voltage-to-current conversion module when the drive signal is high.

2. The hysteresis current-mode controller according to claim 1, characterized in that, The controller further includes: a first transconductance device, a second transconductance device, and a first resistor, wherein... The two input terminals of the first transconductance device are connected to the two ends of the detection resistor, and the output terminal is grounded through the first resistor, and outputs the detection voltage. The non-inverting input terminal of the second transconductance device is connected to the second reference voltage, the inverting input terminal is connected to the dimming voltage, and the output terminal is connected to the output terminal of the first transconductance device.

3. The hysteresis current-mode controller according to claim 1, characterized in that, The voltage width setting module is used to output the first reference voltage when the dimming voltage is greater than the first reference voltage, and to output the dimming voltage when the dimming voltage is less than the first reference voltage.

4. The hysteresis current-mode controller according to claim 3, characterized in that, The voltage width setting module is implemented using a linear voltage regulator.

5. The hysteresis current-mode controller according to claim 4, characterized in that, The linear voltage regulator includes: a first amplifier, a first MOSFET, and a first capacitor, wherein... The non-inverting input terminal of the first amplifier is connected to the first reference voltage, the inverting input terminal is connected to the source terminal of the first MOSFET, and the output terminal is connected to the gate terminal of the first MOSFET. The drain of the first MOS transistor is connected to the dimming voltage, and the source is grounded through the first capacitor, serving as the output of the linear regulated source.

6. The hysteresis current-mode controller according to claim 1, characterized in that, The voltage-to-current conversion module includes: a second amplifier, a second MOSFET, and a second resistor, wherein, The non-inverting input of the second amplifier is connected to the voltage signal output by the voltage width setting module, the inverting input is connected to the source of the second MOS transistor, and the output is connected to the gate of the second MOS transistor. The drain terminal of the second MOS transistor serves as the output terminal of the voltage-to-current conversion module, while the source terminal is grounded through the second resistor.

7. The hysteresis current-mode controller according to claim 1, characterized in that, When the drive signal is high, the hysteresis voltage generation module generates and outputs the upper limit value of the hysteresis voltage based on the current signal output by the voltage-to-current conversion module and the fixed voltage source.

8. The hysteresis current-mode controller according to claim 7, characterized in that, The hysteresis voltage generation module includes: a current mirror unit, an input selection unit, a fixed voltage source, and an adder, wherein... The current mirroring unit is used to mirror the current signal output by the voltage-to-current conversion module. The input selection unit is used to generate a zero voltage output when the drive signal is low, and to generate a non-zero voltage output based on the mirrored current output by the current mirror unit when the drive signal is high. The first input terminal of the adder is connected to the voltage signal output by the input selection unit, the second input terminal is connected to the fixed voltage source, and the output terminal serves as the output terminal of the hysteresis voltage generation module.

9. The hysteresis current-mode controller according to claim 8, characterized in that, The input selection unit includes: a third MOSFET, a third resistor, and an inverter, wherein... The gate of the third MOS transistor is connected to the drive signal through the inverter, the drain is connected to the mirrored current output by the current mirror unit, and the source is grounded. The first end of the third resistor is connected to the drain of the third MOS transistor, and the second end is grounded.

10. A hysteresis current-mode control method based on the hysteresis current-mode controller according to any one of claims 1 to 9, characterized in that, The control method includes: Detects inductor current and generates a detection voltage; The detection voltage and hysteresis voltage are compared, and a drive signal is generated based on the comparison result. The upper and lower limits of the hysteresis voltage are controlled by the drive signal to switch back and forth. The lower limit of the hysteresis voltage is a first fixed value, the upper limit of the hysteresis voltage follows the dimming voltage when the dimming voltage is less than the first reference voltage, and is a second fixed value when the dimming voltage is greater than the first reference voltage, and the second fixed value is related to the first reference voltage.

11. The hysteresis current-mode control method according to claim 10, characterized in that, The method for generating the hysteresis voltage includes: When the drive signal is low, a lower limit value of the hysteresis voltage is generated based on a fixed voltage source; When the drive signal is high, if the dimming voltage is greater than the first reference voltage, an upper limit of the hysteresis voltage is generated based on the first reference voltage and the fixed voltage source; if the dimming voltage is less than the first reference voltage, an upper limit of the hysteresis voltage is generated based on the dimming voltage and the fixed voltage source.

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