Switching drive circuit and method of driving a switch

Abstract

The disclosure of the present application provides a switching driving circuit and a driving method of a switch. A switching driving circuit includes a switch configured to switch a current supplied to a target circuit, a sensing resistor connected to the switch, a controller configured to control the switch by comparing a sensing voltage applied to the sensing resistor with a reference voltage, and a compensation circuit configured to adjust the reference voltage based on an amount of change in an input voltage input to the target circuit and an output voltage output from the target circuit.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2019-0098678, filed with the Korean Intellectual Property Office on August 13, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The disclosure of this application generally relates to switch driving circuits and switch driving methods. Background Technology

[0004] Switching drive circuits can be operated using a switching converter method. Switching converters can be classified according to the ratio of input voltage to output voltage and can include metal-oxide-semiconductor field-effect transistors (MOSFETs) to implement an average inductor current-mode approach.

[0005] Typical drive circuits, including MOSFETs, can perform full-wave rectification of alternating current (AC) power, sense the voltage amplitude of the full-wave rectification, and selectively apply the full-wave rectified voltage to target circuits such as displays based on the sensed voltage amplitude.

[0006] In this example, the sensed voltage amplitude may vary along with the input voltage applied to the target circuit (e.g., a display) or the output voltage output through the target circuit. Due to such variation, there may be a problem where the desired full-wave rectified voltage cannot be applied to the target circuit, and because of this problem, a typical switch driver circuit may fail to drive the drive current used to drive the target circuit with the desired brightness. Summary of the Invention

[0007] The present invention provides a simplified overview of a concept choice in the summary portion, which will be further described in the detailed embodiments described below. This summary portion is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0008] In one general aspect, a switch driving circuit includes: a switch configured to switch current supplied to a target circuit; a sensing resistor connected to the switch; a controller configured to control the switch by comparing a sense voltage applied to the sensing resistor with a reference voltage; and a compensation circuit configured to adjust the reference voltage based on the amount of change between an input voltage input to the target circuit and an output voltage output from the target circuit.

[0009] The controller can open the switch in response to the sensed voltage and the reference voltage being substantially the same.

[0010] The compensation circuit can be configured to adjust the reference voltage to a low value based on the amount of the increase in the input voltage in response to a simultaneous increase in the input voltage and the output voltage, and the compensation circuit can be configured to adjust the reference voltage to a high value based on the amount of the decrease in the input voltage in response to a simultaneous decrease in the input voltage and the output voltage.

[0011] The compensation circuit can be configured to adjust the reference voltage to a low value based on the amount of the increase in the output voltage in response to a constant input voltage and an increase in the output voltage, and the compensation circuit can also be configured to adjust the reference voltage to a high value based on the amount of the decrease in the output voltage in response to a constant input voltage and a decrease in the output voltage.

[0012] The compensation circuit may include a first conversion block configured to convert the level of the input voltage and a second conversion block configured to convert the level of the output voltage.

[0013] The switch drive circuit may also include a voltage divider connected to the switch and the controller and configured to apply a divided voltage to the controller.

[0014] A voltage divider may include a resistor configured to divide a voltage and a capacitor connected in series with the resistor.

[0015] The compensation circuit may include a first conversion block configured to convert the level of the input voltage, and the output voltage may be a voltage divider.

[0016] The compensation circuit can be configured to adjust the reference voltage to a low value based on the amount of the increase in the input voltage in response to a simultaneous increase in the input voltage and the voltage divider voltage, and the compensation circuit can be configured to adjust the reference voltage to a high value based on the amount of the decrease in the input voltage in response to a simultaneous decrease in the input voltage and the voltage divider voltage.

[0017] The compensation circuit can be configured to adjust the reference voltage to a low value based on the amount of the decrease in the voltage divider voltage in response to a constant input voltage and a decrease in the voltage divider voltage, and the compensation circuit can also be configured to adjust the reference voltage to a high value based on the amount of the increase in the voltage divider voltage in response to a constant input voltage and an increase in the voltage divider voltage.

[0018] The controller may include: an input terminal configured to check an input voltage; a voltage divider terminal configured to check a divided voltage; a switch terminal configured to check a switching control signal applied from the controller to the switch; a sensing terminal configured to check a sensed voltage; and a reference voltage terminal configured to check a reference voltage.

[0019] The controller may include at least one comparator configured to compare a sensed voltage with a reference voltage.

[0020] The controller may include: an input terminal configured to check an input voltage; an output terminal configured to check an output voltage; a voltage divider terminal configured to check a divided voltage; a switch terminal configured to check a switching control signal applied from the controller to the switch; a sensing terminal configured to check a sensed voltage; and a reference voltage terminal configured to check a reference voltage.

[0021] The target circuit may include at least one light-emitting device and at least one inductor connected in series with the at least one light-emitting device, wherein the switch is configured to switch the current in the at least one light-emitting device.

[0022] In another general aspect, a method of driving a switch includes: controlling the switch by comparing a sensed voltage applied to a sensing resistor connected to one end of the switch with a reference voltage; measuring an input voltage and an output voltage of a target circuit connected to the other end of the switch; and adjusting the reference voltage according to changes in the input voltage and the output voltage, wherein the switch is turned off in response to the sensed voltage and the reference voltage being substantially the same as each other.

[0023] Control may include: comparing a sensed voltage with a reference voltage; and, in response to the sensed voltage and the reference voltage being substantially the same, outputting a switch control signal via the controller to open the switch.

[0024] In response to a simultaneous increase in both the input and output voltages, the reference voltage can be adjusted to a low value based on the amount of the increase in the input voltage.

[0025] In response to a simultaneous decrease in both the input and output voltages, the reference voltage can be adjusted to a high value based on the amount of decrease in the input voltage.

[0026] In response to a constant input voltage and an increase in output voltage, the reference voltage can be adjusted to a low value based on the amount of increase in output voltage.

[0027] In response to a constant input voltage and a decrease in output voltage, the reference voltage can be adjusted to a high value based on the amount of decrease in output voltage.

[0028] The output voltage can be measured by measuring the voltage divider generated by the voltage divider, which includes a resistor and a capacitor connected in parallel with the switch.

[0029] In response to a simultaneous increase in both the input voltage and the voltage divider, the reference voltage can be adjusted to a low value based on the increase in the input voltage; conversely, in response to a simultaneous decrease in both the input voltage and the voltage divider, the reference voltage can be adjusted to a high value based on the decrease in the input voltage.

[0030] In response to a constant input voltage and a decrease in the voltage divider voltage, the reference voltage can be adjusted to a low value based on the decrease in the voltage divider voltage, and in response to a constant input voltage and an increase in the voltage divider voltage, the reference voltage can be adjusted to a high value based on the increase in the voltage divider voltage.

[0031] In another general aspect, a switch driving circuit includes: a switch configured to switch current supplied to a target circuit; a sensing resistor connected to the switch; a controller configured to control the switch by comparing a sense voltage applied to the sensing resistor with a reference voltage; and a compensation circuit configured to adjust the reference voltage based on one or both of an input voltage input to the target circuit and an output voltage output from the target circuit.

[0032] The controller can open the switch in response to the sensed voltage and the reference voltage being substantially the same.

[0033] The compensation circuit may include one or both of a first conversion block configured to convert the level of the input voltage and a second conversion block configured to convert the level of the output voltage.

[0034] The switch drive circuit may also include a voltage divider connected to the switch and the controller and configured to apply a divided voltage to the controller.

[0035] Other features and aspects will become apparent from the following detailed description, drawings and claims. Attached Figure Description

[0036] Figure 1 This is a view showing a switch drive circuit according to an example.

[0037] Figure 2 It shows in Figure 1 The example shows the compensation circuit inside the switch drive circuit.

[0038] Figure 3 This is a timing diagram of a typical switch drive circuit without compensation circuitry.

[0039] Figure 4 It is a timing diagram based on the example switch drive circuit.

[0040] Figure 5 The example shows a reference voltage that is adjusted according to changes in the input or output voltage applied to the compensation circuit.

[0041] Figure 6 A switch drive circuit based on an example is shown.

[0042] Figure 7 It shows in Figure 6 The example shows the compensation circuit inside the switch drive circuit.

[0043] Figure 8 The example shows a reference voltage that is adjusted according to the input voltage and the voltage divider applied to the compensation circuit.

[0044] Figure 9 It is a timing diagram of each signal generated in the voltage divider.

[0045] Throughout the accompanying drawings and detailed description, the same reference numerals refer to the same elements. The drawings may not be drawn to scale, and for clarity, illustration, and convenience, the relative dimensions, scale, and depiction of elements in the drawings may be enlarged. Detailed Implementation

[0046] The following detailed description is provided to help readers gain a full understanding of the methods, apparatus, and / or systems described herein. However, after understanding the disclosure of this application, various changes, modifications, and equivalent variations of the methods, apparatus, and / or systems described herein will become apparent. For example, the order of operations described herein is merely illustrative and is not limited to the order of operations presented herein, but can be changed except for operations that must occur in a certain order, as will become apparent after understanding the disclosure of this application. Moreover, for the sake of clarity and conciseness, descriptions of features known in the prior art may be omitted.

[0047] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. More precisely, the examples described herein are provided only to illustrate some of the many possible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0048] Throughout the specification, when an element such as a layer, region, or substrate is described as "on another element," "connected to," or "coupled to" another element, it may be directly "on another element," "connected to," or "coupled to" the other element, or there may be one or more other elements in between. Conversely, when an element is described as "directly on another element," "directly connected to," or "directly coupled to" another element, there are no other elements in between.

[0049] As used in this document, the term “and / or” includes any one of the related listed items and any combination of any two or more.

[0050] While this document may use terms such as “first,” “second,” and “third” to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited by these terms. More precisely, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, the first component, part, region, layer, or section referred to in the examples described herein may also be referred to as the second component, part, region, layer, or section.

[0051] For ease of description, spatial relative terms such as “above,” “above,” “below,” and “under” may be used herein to describe the relationship between one element and another shown in the figures. Such spatial relative terms are intended to encompass different orientations of the device during use or operation, in addition to those shown in the figures. For example, if the device in the figures is flipped, an element described as “above” or “above” relative to another element will be “below” or “under” relative to the other element. Thus, depending on the spatial orientation of the device, the term “above” includes both above and below orientations. The device may also be oriented in other ways (e.g., rotated 90 degrees or having other orientations), and the spatial relative terms used herein will be interpreted accordingly.

[0052] The terminology used herein is for the purpose of describing various examples only and is not intended to limit the scope of this disclosure. The articles “a,” “an,” and “the” are also intended to include plural forms unless the context clearly indicates otherwise. The terms “comprising,” “including,” and “having” specify the presence of the stated features, numbers, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, components, elements, and / or combinations thereof.

[0053] Due to manufacturing techniques and / or tolerances, the shapes shown in the accompanying drawings may vary. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include shape variations that may occur during the manufacturing process.

[0054] In this document, it should be noted that the term “may” is used for examples or implementations, such as what an example or implementation may include or implement, meaning that there exists at least one example or implementation that includes or implements such features, and that all examples and implementations are not limited thereto.

[0055] The features of the examples described herein can be combined in various ways, as will become apparent after understanding the disclosure of this application. Furthermore, while the examples described herein have various configurations, other configurations are also possible, as will become apparent after understanding the disclosure of this application.

[0056] The following example can provide a solution even if the input voltage V IN Or output voltage V O The change also applies to the drive current I of the drive circuit. D A constant driving circuit, and a driving method for such a driving circuit.

[0057] Figure 1 A switch drive circuit based on an example is shown.

[0058] according to Figure 1 As an example, and by way of non-limiting example, a switch drive circuit may include a switch 200, a sensing resistor 300, a controller 400, and a voltage divider 500. However, the switch drive circuit is not limited to these exemplary components, and in other examples may include additional components in addition to or in place of these components.

[0059] Switch 200 can be a component used to switch the current supplied to target circuit 100.

[0060] The target circuit 100 may be a circuit that includes a device that emits light when current is supplied, but is not limited to such a circuit. The target circuit 100 may refer to a circuit that includes all devices that perform a specific function when current is supplied to the device.

[0061] When the target circuit 100 is a circuit that includes a device that emits light when current is supplied, it may include at least one light-emitting device 110, at least one capacitor 120 connected in parallel with the light-emitting device 110, at least one diode 140 for rectifying the current input to the light-emitting device 110 and the capacitor 120, and at least one inductor 130 connected in series with the light-emitting device 110 and the capacitor 120 (the capacitor 120 is connected in parallel with the light-emitting device 110).

[0062] The switch 200 can be positioned between the inductor 130 and the controller 400, and can control the inductor current I in the inductor 130 by receiving a switch control signal from the controller 400. L .

[0063] When switch 200 is turned on, the inductor current I L1 or drive current I D Based on the input voltage V IN Flow. When switch 200 is opened, the current I charging in inductor 130 can be released. L2 To drive current I D It is supplied to the light-emitting device.

[0064] Switch 200 can be turned on when the switch control signal corresponds to a positive value such as a high level or 1, and switch 200 can be turned off if the switch control signal corresponds to a non-positive value such as a low level or 0. In this way, controller 400 can regulate the inductor current I supplied to target circuit 100. L or drive current I D Specifically, when the target circuit 100 includes a light-emitting device 110, the brightness of the light-emitting device 110 can be adjusted.

[0065] When switch 200 is turned on, the inductor current I L1 A current can flow through switch 200, and inductor 130 can control the inductor current I. L1 Charging. When switch 200 is open, the current charging in inductor 130 can be provided as discharge current I. L2 This current is supplied to the light-emitting device 110. That is, when switch 200 is open, the inductor discharge current I... L2 It can be used as a current source for inductor 130.

[0066] The sensing resistor 300 can be connected to the switch 200, and can also be electrically connected to both the switch 200 and the controller 400. The sensing voltage V applied to the opposite terminals of the sensing resistor 300... CS It can be applied to the controller 400 through the sensing terminal 443.

[0067] When the inductor current I L When the inductor current I reaches zero, the controller 400 can provide a switching control signal to turn on the switch 200. More specifically, when the inductor current I... L When the voltage drops below zero, the drain terminal of the MOSFET 200 can have a non-positive value, such as a low level or 0, and the voltage divider voltage V ZCD It can achieve a voltage higher than the reference voltage divider V. REF_ZCD Small non-positive values, such as low level or 0, are used to turn on switch 200.

[0068] Sensing voltage V CS This can refer to the voltage applied to the opposite terminals of the sensing resistor 300, and the sensed voltage V. CS The input voltage V can be applied to the controller 400 via sensing terminal 443. IN This can refer to the voltage input to the target circuit 100, and can be applied to the controller 400 through input terminal 446. Output voltage V O The voltage can be output from the target circuit 100 and can be applied to the controller 400 via the output terminal 447. Additionally, the sensed voltage V can be checked externally using the terminal. CS Input voltage VIN and output voltage V O .

[0069] The controller 400 can control the sensing voltage V applied to the sensing resistor 300. CS With the preset reference voltage V REF The comparison is used to control switch 200.

[0070] Reference voltage V REF It can have preset values, and the controller 400 can adjust the reference voltage V. REF The set value. By adjusting the reference voltage V REF The set value, even when the sensing voltage V CS According to the input voltage V IN Or output voltage V O When the change in quantity changes, the inductor current I L or drive current I D It can also be constant. Alternatively, the reference voltage V can be checked externally using reference voltage terminal 442. REF .

[0071] Controller 400 can adjust the reference voltage V REF The setpoint value may include comparators 420 and 430 and a memory device 410. A gate driver may also be included, one end of which can be connected to the memory device 410 and the other end to the switch 200. The gate driver can amplify the output of the memory device 410 to generate the voltage required to turn the switch 200 on or off, and can output the switch control signal with low impedance. The gate driver can quickly provide the switch control signal to the switch 200 based on changes in the output value of the memory device 410. For example, the memory device 410 may be implemented as an SR latch.

[0072] Additionally, as a non-limiting example, the controller 400 may include an input terminal 446, an output terminal 447, a reference voltage terminal 442, a ground terminal 444, a voltage divider terminal 441, and a switch terminal 445. The input voltage V input to the target circuit 100 via the input terminal 446 can be checked. IN This is to ensure that it has an appropriate value. Similarly, the output voltage V output from the target circuit 100 through the output terminal 447 can be checked. O The controller 400 can be grounded via grounding terminal 444. As with other voltages, the voltage divider voltage V can be checked via voltage divider terminal 441. ZCD The controller 400 can send a switch control signal to the switch 200 via the switch terminal 445.

[0073] The example switch drive circuit may also include a voltage divider 500.

[0074] Voltage divider 500 can be connected to switch 200 and controller 400, and can adjust the voltage V applied from switch 200 to controller 400. ZCD In addition, voltage divider 500 can be connected to target circuit 100.

[0075] Voltage divider 500 can convert the output voltage V from target circuit 100 into voltage V. O Divide by the desired voltage amplitude. To achieve this, voltage divider 500 may include at least one resistor and at least one capacitor. For example, a first voltage divider resistor 520, a second voltage divider resistor 530, and a capacitor 510 may be included in voltage divider 500, and the first voltage divider resistor 520, the second voltage divider resistor 530, and the capacitor 510 may be connected in series. In this example, each of the first voltage divider resistor 520 and the second voltage divider resistor 530 may not be limited to a single resistor, and in other examples, the number may not be limited.

[0076] Capacitor 510 can be electrically connected to inductor 130 and switch 200. Capacitor 510 can interrupt the inductor current I. L The DC component is allowed to pass through, and the AC component can also pass through. At this time, the capacitor voltage V between capacitor 510 and the first voltage divider resistor 520 can be measured. C .

[0077] The first voltage divider resistor 520 and the second voltage divider resistor 530 can divide the AC component of the voltage passing through the capacitor 510. Such a divided voltage can be applied to the controller 400, for example, through the voltage divider terminal 441 of the controller 400.

[0078] The voltage divided by the voltage divider 500 can be adjusted by the ratio of the resistance values ​​of the first voltage divider resistor 520 and the second voltage divider resistor 530. For example, when the resistance ratio of the first voltage divider resistor 520 and the second voltage divider resistor 530 corresponds to a 9:1 ratio, the voltage divided by the voltage V applied to the controller 400 is... ZCD This can correspond to 1 / 10 of the AC component voltage through capacitor 510.

[0079] Because it is possible to use an input voltage V that is substantially lower than that received from the input power supply. IN The voltage is used to operate the controller 400, so the first voltage divider resistor 520 and the second voltage divider resistor 530 can prevent the controller 400 from being overloaded.

[0080] Figure 2 The compensation circuit inside the switch drive circuit according to the example is shown.

[0081] according to Figure 2 For example, the compensation circuit 450 can receive the input voltage V. IN and output voltage V O The compensation circuit 450 may include: a first conversion block 460, which converts the input voltage V IN The voltage level; and the second conversion block 470, whose converted output voltage V O The compensation circuit 450 can adjust the input voltage V sensed by the first conversion block 460 and the second conversion block 470 according to the voltage level. IN and output voltage V O Reference voltage V REF The setting value is changed to the modified reference voltage V. REF’ .

[0082] The compensation circuit 450 can be configured inside the controller 400, but its location is not limited to this example configuration and can be configured differently in other examples. The compensation circuit 450 can share terminals of the controller 400, and the compensation circuit 450 can be connected to a second comparator 430 included in the controller 400.

[0083] Input voltage V IN and output voltage V O The voltage could exceed tens of volts, making it potentially unsafe for use in an IC. Therefore, it may be necessary to reduce the input voltage V. IN amplitude and output voltage V O The amplitude is adjusted to an amplitude available within the IC by a first conversion block 460 and a second conversion block 470, which are separate components from the IC. The first conversion block 460 can adjust the input voltage V to an amplitude available within the IC. IN The amplitude is adjusted to a value usable within the IC. Additionally, the second conversion block 470 can adjust the output voltage V... O The amplitude is adjusted to the amplitude available within the IC.

[0084] The compensation circuit 450 can convert the input voltage V using the first conversion block 460 and the second conversion block 470. IN and output voltage V O By adjusting the amplitude to an appropriate level to detect changes, a modified reference voltage V can be output based on the sensed changes. REF’ And the modified reference voltage V REF’ The modified reference voltage node 448 can be applied to the inverting terminal of the second comparator 430. The compensation circuit 450 can sense the input voltage V with adjusted amplitude. IN Or output voltage V O To effectively sense the change in input voltage V IN Or input voltage V IN The change in quantity.

[0085] Figure 3 This is a timing diagram of a traditional switch drive circuit without compensation circuitry. Figure 4 It is a timing diagram based on the example switch drive circuit.

[0086] Figure 3 and Figure 4 The dashed line in the example represents the input voltage V. IN The additional examples, and the solid lines indicate examples where a constant input voltage is provided.

[0087] Reference Figure 3 and Figure 4 For example, the sensing voltage V is used as a reference voltage to provide current to the target circuit 100. CS It can be adjusted according to the input voltage V applied to the target circuit 100. IN Or the output voltage V from the target circuit 100 O Change with change.

[0088] Reference Figure 3 and Figure 4 For example, when the sensed voltage V CS and reference voltage V REF When they are essentially the same, the controller 400 can use a switch control signal to disconnect the switch 200.

[0089] according to Figure 3 For example, when the input voltage V IN When the current increases, the inductor current I L It can be increased, and the rising current I L1 The slope can be increased. When the rising current I... L1 As the slope increases, the sensed voltage V CS The slope can also be increased. Therefore, a significant excess of the reference voltage may occur, leading to an increase in the drive current I. D The increase is very high. When the sensed voltage V CS and reference voltage V REF When they are essentially the same, switch 200 can be turned off, which may be due to the required delay time.

[0090] In such an example, the rising current I L1 This can refer to the inductor current I when switch 200 is turned on. L The current in the rising portion. The falling current I. L2 This could refer to the inductor current I when switch 200 is open. L The current in the decreasing portion.

[0091] In contrast, when the input voltage V INWhen the current decreases, the inductor current I L Decrease, and increase current I L1 The slope also decreases. As the current I rises... L1 The slope decreases, and the sensed voltage V CS It can also momentarily drop below the reference voltage V REF When the sensed voltage V CS Below the reference voltage V REF At that time, the driving current I D It can also be reduced accordingly.

[0092] When the output voltage V O When increasing or decreasing, it may also occur according to the input voltage V. IN Change in sensing voltage V CS The input voltage V changes. IN Or output voltage V O Changes may affect the sensing voltage V CS This may cause the drive current I D The changes. In particular, when the target circuit 100 includes a light-emitting device 110, the light-emitting device 110 may not be able to operate at the desired brightness level.

[0093] To solve such a problem Figure 3 The following example raises the problem shown in the example. Figure 4 The example illustrates a switch-driven method. When the reference voltage V... REF The set value changed the sensing voltage V CS Change V CS’ -V CS At this time, it can prevent the drive current I D The changes.

[0094] Therefore, if the sensing voltage V can be measured CS The change in voltage V is then the reference voltage V REF The set value can be determined based on the sensed voltage V. CS Change V CS’ -V CS And this change can prevent the drive current I D change.

[0095] However, the input voltage V IN Or output voltage V O Changes may affect the sensing voltage V CS Therefore, it may be difficult to accurately measure the sensed voltage V switched by switch 200 every minute. CS Change V CS’ -V CS Therefore, it may be preferable to measure the input voltage V, which is relatively easy to measure. INand output voltage V O The change in voltage, and then based on this change, the reference voltage V is adjusted. REF The set value.

[0096] Specifically, if due to the input voltage V IN and output voltage V O The increase in reference voltage V REF Reduced sensing voltage V CS The increase in the amount can prevent the drive current I D Increase. In contrast, when due to the input voltage V IN and output voltage V O The decrease in voltage V caused by the reduction in voltage V REF Increased sensing voltage V CS When the amount of reduction is reduced, it can prevent the drive current I D The compensation circuit 450 can reduce the driving current I flowing in the light-emitting device 110 by appropriately controlling it. D To operate the light-emitting device 110 with the desired brightness.

[0097] Figure 5 This illustrates a reference voltage that is adjusted according to variations in the input or output voltage applied to the compensation circuit, as shown in the example.

[0098] Figure 5 The input voltage V is shown in (a). IN and output voltage V O Simultaneously changing signals. Typically, the output voltage V O It can vary with the input voltage V IN It changes with the changes.

[0099] Figure 5 (b) shows the input voltage V. IN Keep the output voltage V constant O Signals that vary due to other factors. Other factors may include examples of variations in the resistance of a device due to dispersion in the semiconductor manufacturing process.

[0100] according to Figure 5 In (a), it can be related to the input voltage V IN The change will be in the opposite direction to the existing reference voltage V REF The output is the modified reference voltage V. REF’ Because the output voltage V O Based on the input voltage V IN However, this varies, so in this example, it might be preferable to base it on the input voltage V. IN Instead of output voltage V O To output the modified reference voltage VREF’ .

[0101] Specifically, when the input voltage V IN and output voltage V O When increasing simultaneously, it can be based on the input voltage V IN The increase will affect the reference voltage V. REF Adjust to have a low value. In contrast, when the input voltage V IN and output voltage V O When both decrease simultaneously, it can be based on the input voltage V IN The reduction in the reference voltage V REF Adjust to have a high value.

[0102] according to Figure 5 In (b), when the input voltage V IN Keep the output voltage V constant O When increasing, it can be based on the output voltage V. O The increase will affect the reference voltage V. REF Adjust to have a low value. In contrast, when the input voltage V IN The output voltage V remains constant. O When decreasing, it can be based on the output voltage V O The reduction in the reference voltage V REF Adjust to have a high value.

[0103] The switch drive device according to another example will then be described in detail with reference to the accompanying drawings. For reference only, the other example will be described in comparison with the example described above, and similar parts will be omitted by referring to the above description.

[0104] Figure 6 A switch drive circuit based on an example is shown.

[0105] according to Figure 6 As an example, and by way of non-limiting example, a switch drive circuit according to this example may include a switch 200, a sensing resistor 300, a controller 400, and a voltage divider 500, and may contain other elements besides these elements or other elements that replace these elements.

[0106] according to Figure 6 The example switch drive circuit controller 400 may include an input terminal 446, a reference voltage terminal 442, a ground terminal 444, a voltage divider terminal 441, and a switch terminal 445. According to... Figure 6 The example in, with Figure 1 Unlike other examples, controller 400 may not include a separate output terminal 447. That is, controller 400 can receive a voltage divider V. ZCD Instead of output voltage V OAs the input to the compensation circuit. In this example, the voltage V is divided by the voltage divider 500. ZCD It can have a sufficiently low voltage value to be applied to the controller 400.

[0107] Figure 7 It shows that according to Figure 6 The example shows the compensation circuit inside the switch drive circuit.

[0108] according to Figure 7 For example, the compensation circuit included in the controller 400 may include checking the input voltage V. IN The compensation circuit 450 of the input terminal 446. In this case, with Figure 2 Unlike other examples, the compensation circuit 450 may not include the output terminal 447 and the second conversion block 470, and the divided voltage V can be applied directly from the voltage divider terminal 441. ZCD .

[0109] Input voltage V IN It may have an amplitude exceeding tens of volts, causing the input voltage V to... IN It may not be usable in an IC. Therefore, a separate input voltage V may be required. IN The first conversion block 460 adjusts the input voltage V to a level usable within the IC. IN The amplitude is adjusted to the amplitude available within the IC.

[0110] Therefore, in such an example, when the input voltage V is converted using the first conversion block 460... IN When adjusted to an appropriate amplitude, the input voltage V can be reduced to the adjusted amplitude. IN A compensation circuit 450 is applied inside the controller 400. In this way, the controller 400 can effectively sense the input voltage V. IN The change in quantity.

[0111] Additionally, the following description provides, for example Figure 8 The example shown illustrates a switch-driven method to address existing issues such as... Figure 3 The example illustrates the problem. According to... Figure 8 For example, when the output voltage V O When the voltage V of the capacitor changes, C and voltage divider V ZCD The waveform can also change.

[0112] When the reference voltage V REF The set value is based on the sensing voltage V CS When the amount of change changes, it can prevent the drive current I from changing. D Change. However, with Figure 1Unlike the previous example, in this example, the reference voltage V... REF It can be based on the voltage divider V of voltage divider 500 ZCD And change.

[0113] If the sensing voltage V CS The change is measurable, so it can be determined according to the sensed voltage V. CS The change in the reference voltage V REF The set value. Therefore, it can prevent the drive current I. D Things have changed.

[0114] However, it may be difficult to accurately measure the sensed voltage V. CS The change in the input voltage V. Therefore, it may be preferable to measure the input voltage V, which is relatively easy to measure. IN and voltage divider V ZCD The change in the input voltage V, as discussed above. IN and voltage divider V ZCD The change in the reference voltage V REF The set value.

[0115] By using voltage divider 500, the voltage V can be appropriately reduced. ZCD The amplitude. Voltage divider V ZCD Also related to the output voltage V O Electrical correlation. That is, when measuring the voltage divider voltage V... ZCD Instead of output voltage V O At that time, a compensation circuit 450 that does not include the second conversion block 470 can be designed accordingly.

[0116] Specifically, in such an example, when due to the input voltage V IN and voltage divider V ZCD The increase in reference voltage V REF Reduced sensing voltage V CS When the amount is increased, it can prevent the drive current I D Increase. In contrast, if due to the input voltage V IN and voltage divider V ZCD The decrease in voltage V caused by the reduction in voltage V REF Increased sensing voltage V CS The reduction in the amount of [something] can also prevent the drive current I [from falling]. D The driving current I flowing through the light-emitting device 110 is reduced. Therefore, by controlling the driving current I in this described manner... D The compensation circuit 450 can operate the light-emitting device 110 at the desired brightness. For example, Figure 8 It shows the application to the basis Figure 6 and Figure 7 The input voltage V of the example compensation circuitIN and voltage divider V ZCD The reference voltage is adjusted according to the changes.

[0117] However, in Figure 8 In the example, the capacitor voltage V C and voltage divider V ZCD It can be changed periodically by switching switch 200. Therefore, subsequently, "the voltage divider V" ZCD "Can refer to the connection within it" Figure 8 voltage divider V ZCD The average point or peak value of the sine waveform.

[0118] Figure 8 The input voltage V is shown in (a). IN and voltage divider V ZCD Simultaneously changing signals. Typically, voltage divider V ZCD It can be adjusted according to the input voltage V IN It changes with the changes.

[0119] Figure 8 (b) shows the input voltage V. IN Keep constant but divider voltage V ZCD Signals that may vary due to other factors. Other factors may include examples where the resistance value of a device may vary due to dispersion that occurs during semiconductor manufacturing.

[0120] according to Figure 8 In (a), it can be related to the input voltage V IN The existing reference voltage V will be in the opposite direction. REF The output is the modified reference voltage V. REF’ Due to the voltage divider V ZCD It can vary with the input voltage V IN It changes with the reference voltage V; therefore, in this example, for the reference voltage V... REF The preferred method may be based on the input voltage V. IN Instead of voltage divider V ZCD The modified reference voltage V is output. REF’ .

[0121] Specifically, when the input voltage V IN and voltage divider V ZCD When both are increased, the compensation circuit 450 can be based on the input voltage V. IN The increase will affect the reference voltage V. REF Adjust to have a low value. In contrast, when the input voltage V IN and voltage divider V ZCD When both decrease simultaneously, the compensation circuit 450 can be based on the input voltage V. INThe reduction in the reference voltage V REF Adjust to have a high value.

[0122] according to Figure 8 In (b), when the input voltage V IN Keep constant, but the voltage divider V ZCD When the voltage decreases, the compensation circuit 450 can be based on the voltage divider V. ZCD The reduction in the reference voltage V REF Adjust to have a low value. In contrast, when the input voltage V IN Keep constant, but the voltage divider V ZCD When increased, the compensation circuit 450 can be based on the voltage divider V. ZCD The increase will affect the reference voltage V. REF Adjust to have a high value.

[0123] Subsequently, according to Figure 1 and Figure 6 The example of a switch drive circuit is described in further detail, in which switch 200 can be implemented as a MOSFET.

[0124] When switch 200 is implemented as a MOSFET, the switch control signal can be sent to the gate of the MOSFET through the gate terminal, thereby controlling the inductor current I. L In other words, when the switch control signal corresponds to a positive value such as a high level or 1, the switch 200 can be turned on, and when the switch control signal corresponds to a non-positive value such as a low level or 0, the switch 200 can be turned off. In this way, the controller 400 can adjust the current supplied to the target circuit 100 in order to adjust the brightness of the light-emitting device 110 included in the target circuit 100.

[0125] The controller 400 can be connected to the gate terminal of the MOSFET, the target circuit 100 can be connected to the drain terminal, and the sensing resistor 300 can be connected to the source terminal.

[0126] When the sensing voltage V applied to the sensing resistor 300 CS and preset reference voltage V REF When they are essentially the same, the controller 400 can send a switch control signal to the gate terminal of the MOSFET to turn off the switch 200.

[0127] The drain terminal can be connected to voltage divider 500 and target circuit 100. Voltage divider 500 may include a capacitor 510 connected in series, a first voltage divider resistor 520 and a second voltage divider resistor 530, and a voltage divider terminal 441 may be electrically connected between the first voltage divider resistor 520 and the second voltage divider resistor 530. In this example, the voltage measured between capacitor 510 and the first voltage divider resistor 520 may be referred to as capacitor voltage V. C .

[0128] Capacitor 510 of voltage divider 500 can block inductor current I. L The current flows into the first voltage divider resistor 520 and the second voltage divider resistor 530. Because when all the inductor currents I... L When the current flows through switch 200 into sensing resistor 300, the driving current I flowing through light-emitting device 110 can be precisely controlled by switch 200. D Therefore, this kind of obstruction may occur.

[0129] Specifically, capacitor 510 of voltage divider 500 blocks DC current and prevents current from flowing into voltage divider 500, regardless of whether the MOSFET is on or off. If capacitor 510 of voltage divider 500 were not present, the inductor current I... L A portion of the voltage can flow into the voltage divider 500 at the drain of the MOSFET. Therefore, an example could occur where the voltage divider V... ZCD Not lower than the reference voltage divider V REF _ ZCD This prevents the MOSFET from being turned on. Additionally, if current flows into the voltage divider, it may be difficult to measure the accurate sense voltage V. CS This makes it potentially difficult to control a constant current. For this reason, an example can be provided that includes a capacitor 510 when introducing a voltage divider 500.

[0130] Figure 9 It is a timing diagram of the various signals generated in the voltage divider.

[0131] according to Figure 9 For example, even when capacitor 510 is included, the drain voltage V is reduced. DRAIN At the same time, the voltage divider V can also be reduced. ZCD .exist Figure 9 In the example, the rectangles related to the passage of time can be identified by dashed lines, similar to the rectangles in the other figures. Therefore, even the reference voltage V... REF The setting value is based on the voltage divider voltage V. ZCD The effect of this change can also be related to the output voltage V. O Change the reference voltage V REF The settings are the same.

[0132] according to Figure 9 For example, when the MOSFET is turned on, the inductor current I... L It can flow in inductor 130. When the inductor current I... L According to I L1 When it starts to increase, the inductor current I L1 It can flow through the sensing resistor R CS And when the sensing voltage V CS Equal to reference voltage V REF At that time, the voltage V at the gate terminal of the MOSFET GATE It can be reduced, and the MOSFET can be turned off.

[0133] according to Figure 9 For example, when the MOSFET is turned off, the inductor current I... L You can follow I L2 It begins to decrease, and when the inductor current I... L When the current is less than 0A, the voltage at the drain terminal can begin to decrease. When the drain voltage V... DRAIN When the voltage decreases, the capacitor voltage V C and voltage divider V ZCD It can also be reduced. When the voltage divider V ZCD Less than the reference voltage divider V REF_ZCD At that time, the voltage V at the gate terminal GATE You can add more to turn on the MOSFET.

[0134] according to Figure 9 For example, capacitor voltage V C It can include both positive and negative peak values. Figure 9 The example shows that the voltage at the drain terminal can rise from a voltage level of 0V to the input voltage V at a positive peak. IN .in addition, Figure 9 The example shows that the voltage at the drain terminal can be reduced from the input voltage V at the negative peak. IN The amplitude decreases and returns to the 0V voltage level.

[0135] according to Figure 9 Example, voltage divider V ZCD This can refer to the capacitor voltage V. C The voltage is divided by the first voltage divider resistor 520 and the second voltage divider resistor 530. However, a parasitic diode 600 may also be included between the voltage divider terminal 441 and the ground terminal 444. When the parasitic diode 600 is present, the divided voltage V ZCD It may not be allowed to be below -0.7V.

[0136] The switch driving method according to another example is then described in further detail.

[0137] Another example of a switch driving method may include: applying a sensing voltage V to a sensing resistor 300 connected to one end of the switch 200. CS With the preset reference voltage V REF The comparison is used to control switch 200, and the input voltage V of the target circuit 100 connected to the other end of switch 200 is measured. IN and output voltage V O And according to the input voltage V IN Or output voltage V O Adjusting the reference voltage V by the change REF And in sensing voltage V CS and reference voltage V REF When they are basically the same, switch 200 is turned off.

[0138] Control may include: sensing voltage V CS With reference voltage V REF Compare; and when the sensed voltage V CS and reference voltage V REF When they are basically the same, the controller 400 outputs a switch control signal to disconnect the switch 200.

[0139] When the input voltage V IN and output voltage V O When the voltage increases, the reference voltage V can be adjusted based on the amount of increase. REF Adjust it to have a low value.

[0140] Additionally, when the input voltage V IN and output voltage V O When the voltage decreases, the reference voltage can be adjusted based on the amount of decrease, adjusting the reference voltage V. REF Adjust to have a high value.

[0141] According to the switch drive circuit and driving method of this example, even at the input voltage V IN Or output voltage V O If the reference voltage V changes, it can also be changed. REF Adjust to match the input voltage V IN Or output voltage V O The change in the driving current I is kept constant accordingly. D .

[0142] Used to perform the operations described in this application Figures 1 to 9The target circuit 100, light-emitting device 110, capacitor 120, inductor 130, diode 140, switch 200, sensing resistor 300, controller 400, voltage divider terminal 441, reference voltage terminal 442, sensing terminal 443, ground terminal 444, switch terminal 445, input terminal 446, output terminal 447, compensation circuit 450, first conversion block 460, second conversion block 470, voltage divider 500, capacitor 510, first voltage divider resistor 520, and second voltage divider resistor 530 are implemented by hardware components configured to perform the operations described in this application (which are performed by hardware components). Examples of hardware components that may be used to perform the operations described in this application when appropriate include buffers, transistors, controllers, sensors, generators, drivers, memories, comparators, arithmetic logic units, adders, subtractors, multipliers, dividers, integrators, and any other electronic components configured to perform the operations described in this application.

[0143] While this disclosure includes specific examples, it will become apparent upon understanding the disclosure of this application that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered only for descriptive purposes and not for limiting purposes. The description of features or aspects in each example is intended to be applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in a different manner and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure is not defined by the detailed description but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in this disclosure.

Claims

1. A switch driving circuit, comprising: A switch, configured to switch the current supplied to a target circuit; A sensing resistor connected to the switch; A controller configured to control the switch by comparing a sensed voltage applied to the sense resistor with a reference voltage; as well as A compensation circuit is configured to adjust the reference voltage based on the change between the input voltage input to the target circuit and the output voltage output from the target circuit. The compensation circuit includes: A first conversion block, connected to the input terminal, is configured to convert the level of the input voltage, and The second conversion block, connected to the output terminal, is configured to convert the level of the output voltage, and The compensation circuit independently processes the change in the input voltage of the first conversion block and the change in the output voltage of the second conversion block, and generates a modified reference voltage based on the processed change in input or output voltage.

2. The switch driving circuit according to claim 1, in, The controller disconnects the switch in response to the sensed voltage and the modified reference voltage being substantially the same as each other.

3. The switch driving circuit according to claim 1, wherein, The compensation circuit is configured to adjust the reference voltage to a low value based on the amount of the increase in the input voltage in response to a simultaneous increase in the input voltage and the output voltage. The compensation circuit is configured to adjust the reference voltage to a high value based on the amount of decrease in the input voltage in response to a simultaneous decrease in both the input voltage and the output voltage.

4. The switch driving circuit according to claim 1, wherein, The compensation circuit is configured to adjust the reference voltage to a low value based on the amount of the increase in the output voltage, in response to a constant input voltage and an increase in the output voltage. The compensation circuit is configured to adjust the reference voltage to a high value based on the amount of the decrease in the output voltage in response to a constant input voltage and a decrease in the output voltage.

5. The switch driving circuit according to claim 1 further includes: A voltage divider, connected to the switch and the controller, is configured to apply a voltage divider to the controller.

6. The switch driving circuit according to claim 5, wherein, The voltage divider includes: A resistor configured to divide the voltage; and A capacitor connected in series with the resistor.

7. The switch driving circuit according to claim 5, wherein, The output voltage is the voltage divider voltage.

8. The switch driving circuit according to claim 7, in, The compensation circuit is configured to adjust the reference voltage to a low value based on the amount of the increase in the input voltage and the voltage divider voltage in response to a simultaneous increase in the input voltage and the voltage divider voltage. The compensation circuit is configured to adjust the reference voltage to a high value in response to a simultaneous decrease in the input voltage and the voltage divider voltage, based on the amount of the decrease in the input voltage.

9. The switch driving circuit according to claim 7, wherein, The compensation circuit is configured to adjust the reference voltage to a low value based on the amount of the decrease in the reference voltage in response to a constant input voltage and a decrease in the voltage divider voltage. The compensation circuit is configured to adjust the reference voltage to a high value based on the amount of the increase in the voltage divider voltage in response to a constant input voltage and an increase in the voltage divider voltage.

10. The switch driving circuit according to claim 7, wherein, The controller includes: Voltage divider terminals, which are configured to check the divided voltage; A switch terminal configured to check a switch control signal applied to the switch from the controller; A sensing terminal configured to check the sensed voltage; and A reference voltage terminal, configured to check the reference voltage, and The input terminal is configured to check the input voltage.

11. The switch driving circuit according to claim 5, wherein, The controller includes at least one comparator configured to compare the sensed voltage with the modified reference voltage.

12. The switch driving circuit according to claim 5, wherein, The controller includes: Voltage divider terminals, which are configured to check the divided voltage; A switch terminal configured to check a switch control signal applied to the switch from the controller; A sensing terminal configured to check the sensed voltage; and A reference voltage terminal, configured to check the reference voltage, and The input terminal is configured to check the input voltage, and the output terminal is configured to check the output voltage.

13. The switch driving circuit according to claim 1, wherein, The target circuit includes: At least one light-emitting device; and At least one inductor connected in series with the light-emitting device; and The switch is configured to switch the current in the at least one inductor.

14. A method for driving a switch, the method comprising: The switch is controlled by comparing a sense voltage applied to a sense resistor connected to one end of the switch with a reference voltage; Measure the input and output voltages of the target circuit connected to the other end of the switch; Converts the levels of input and output voltages; as well as The changes in the input voltage of the first conversion block and the changes in the output voltage of the second conversion block are processed independently, and a reference voltage is adjusted based on the independently processed changes in the input or output voltage for comparison with the sensed voltage. The switch is turned off in response to the sensed voltage and the modified reference voltage being substantially the same as each other.

15. The method according to claim 14, wherein, The control includes: Compare the sensed voltage with the modified reference voltage; and In response to the sensing voltage and the modified reference voltage being substantially the same as each other, the controller outputs a switch control signal to open the switch.

16. The method according to claim 14, in, In response to a simultaneous increase in both the input voltage and the output voltage, the reference voltage is adjusted to a low value based on the amount of the increase in the input voltage.

17. The method according to claim 14, in, In response to a simultaneous decrease in both the input voltage and the output voltage, the reference voltage is adjusted to a high value based on the amount of decrease in the input voltage.

18. The method according to claim 14, in, In response to a constant input voltage and an increase in the output voltage, the reference voltage is adjusted to a low value based on the amount of the increase in the output voltage.

19. The method according to claim 14, in, In response to a constant input voltage and a decrease in output voltage, the reference voltage is adjusted to a high value based on the amount of decrease in output voltage.

20. The method according to claim 14, in, The output voltage is measured by a voltage divider generated by a voltage divider, which includes a resistor and a capacitor connected in parallel with the switch.

21. The method according to claim 20, in, In response to a simultaneous increase in both the input voltage and the voltage divider, the reference voltage is adjusted to a low value based on the amount of the increase in the input voltage. In response to a simultaneous decrease in both the input voltage and the voltage divider, the reference voltage is adjusted to a high value based on the amount of decrease in the input voltage.

22. The method according to claim 20, in, In response to a constant input voltage and a decrease in the voltage divider, the reference voltage is adjusted to have a low value based on the amount of decrease in the voltage divider. In response to a constant input voltage and an increase in the voltage divider voltage, the reference voltage is adjusted to have a high value based on the amount of increase in the voltage divider voltage.

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