Apparatus comprising controller for switching converter

Abstract

The invention relates to an apparatus including a controller for a switching converter. The apparatus comprises a controller for a switching converter for receiving an input voltage and for providing an output voltage, the switching converter comprising a first switch and an energy storage element, the controller being controlled. And a controller configured to provide a first control signal to the first switch, the first control signal having a switching frequency, and control the switching frequency such that the switching frequency is substantially unaffected by a change in one or more of the load current, an equivalent series resistance of the energy storage element, and an on resistance of the first switch.

Description

Technical Field

[0001] The present disclosure relates to an apparatus including a controller for a switching converter. Background Art

[0002] A switching converter is an electronic device used to efficiently convert electrical energy from one form to another.

[0003] Switching converters can step up (boost), step down (buck), or invert the input voltage depending on the desired output voltage. They are able to provide a regulated output voltage with input voltage variations.

[0004] The controller for a switching converter is a key component that manages the operation and regulation of the converter. It is responsible for controlling the switching signals to maintain the desired output voltage. Summary of the invention

[0005] It is desirable to optimize the operation of a controller for a switching converter.

[0006] According to a first aspect of the present disclosure, a device is provided, comprising a controller for a switching converter, the switching converter being used to receive an input voltage and to provide an output voltage, the switching converter comprising a first switch and an energy storage element, the controller being configured to provide a first control signal to the first switch, the first control signal having a switching frequency, and controlling the switching frequency so that the switching frequency is substantially unaffected by changes in one or more of i) a load current, ii) an equivalent series resistance of the energy storage element, and iii) an on-resistance of the first switch.

[0007] Optionally, the controller is configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in one or more of i) load current, ii) equivalent series resistance of the energy storage element and iii) on-resistance of the first switch.

[0008] Optionally, the first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time, and the controller is configured to set the on time and / or the off time based on one or more of i) the load current, ii) the equivalent series resistance of the energy storage element and iii) the on-resistance of the first switch, thereby controlling the switching frequency so that the switching frequency is substantially unaffected by changes.

[0009] Optionally, the controller is configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in one or more of i) load current, ii) equivalent series resistance of the energy storage element and iii) on-resistance of the first switch.

[0010] Optionally, the controller is configured to set the on-time and / or the off-time using the input voltage, the output voltage, the load current, the equivalent series resistance of the energy storage element and the on-resistance of the first switch.

[0011] Optionally, the controller is configured to receive information about one or more of the load current, the equivalent series resistance of the energy storage element and the on-resistance of the first switch.

[0012] Optionally, the device comprises a current sensor configured to measure the load current and provide information about the load current to the controller.

[0013] Optionally, the switching converter comprises a buck converter comprising a first switch and a second switch, wherein the energy storage element comprises an inductor, and the controller is configured to provide a second control signal to the second switch, the control signal having a switching frequency.

[0014] Optionally, the switching converter comprises a buck converter, a boost converter or a buck-boost converter comprising a first switch and a second switch, wherein the energy storage element comprises an inductor, and the controller is configured to provide a second control signal to the second switch, the control signal having a switching frequency.

[0015] Optionally, the controller is configured to control the switching frequency such that the switching frequency is substantially unaffected by changes in the on-resistance of the second switch.

[0016] Optionally, the first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time, and the controller is configured to set the on time and / or the off time based on the load current, the equivalent series resistance of the energy storage element, the on-resistance of the first switch and the on-resistance of the second switch, thereby controlling the switching frequency so that the switching frequency is substantially unaffected by the changes.

[0017] Optionally, the controller is configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in the load current, the equivalent series resistance of the energy storage element, the on-resistance of the first switch and the on-resistance of the second switch.

[0018] Optionally, the controller is configured to set the on-time and / or the off-time using the input voltage, the output voltage, the load current, the equivalent series resistance of the energy storage element, the on-resistance of the first switch and the on-resistance of the second switch.

[0019] Optionally, the on-time set by the controller is is proportional to, where Vin is the input voltage, IL is the load current, RH is the on-resistance of the first switch, RL is the on-resistance of the second switch, and Rind is the equivalent series resistance of the energy storage element.

[0020] Optionally, the second control signal is the inversion of the first control signal.

[0021] Optionally, the device includes a replica module configured to generate a replica output voltage that is substantially unaffected by changes in one or more of i) a load current, ii) an equivalent series resistance of the energy storage element, and iii) an on-resistance of the first switch, wherein the controller is configured to receive the replica output voltage and use the replica output voltage to control the switching frequency.

[0022] Optionally, the controller is configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in one or more of i) load current, ii) equivalent series resistance of the energy storage element and iii) on-resistance of the first switch.

[0023] Optionally, the first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time, and the controller is configured to use the replica output voltage to set the on time and / or the off time, thereby controlling the switching frequency so that the switching frequency is substantially unaffected by the change.

[0024] Optionally, the controller is configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in one or more of i) load current, ii) equivalent series resistance of the energy storage element and iii) on-resistance of the first switch.

[0025] Optionally, the controller is configured to use the input voltage and the replica output voltage to set the on-time and / or the off-time.

[0026] Optionally, the switching converter comprises a buck converter comprising a first switch and a second switch, wherein the energy storage element comprises an inductor, and the controller is configured to provide a second control signal to the second switch, the control signal having a switching frequency.

[0027] Optionally, the controller is configured to control the switching frequency such that the switching frequency is substantially unaffected by changes in the on-resistance of the second switch.

[0028] Optionally, the first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time, and the controller is configured to use the replica output voltage to set the on time and / or the off time, thereby controlling the switching frequency so that the switching frequency is substantially unaffected by the change.

[0029] Optionally, the controller is configured to use the input voltage and the replica output voltage to set the on-time and / or the off-time.

[0030] Optionally, the on-time as set by the controller is proportional to the replica output voltage divided by the input voltage.

[0031] Optionally, the replica module comprises a replica power stage comprising a replica first switch.

[0032] Optionally, the replica module comprises a filter stage coupled to the replica power stage.

[0033] Optionally, the replica module comprises a voltage buffer coupled to the filter stage and configured to provide the replica output voltage.

[0034] Optionally, the first switch comprises a transistor.

[0035] Optionally, the transistor is a split-gate field effect transistor.

[0036] Optionally, the energy storage element comprises an inductor.

[0037] Optionally, the switching converter is a DC-DC switching converter.

[0038] Optionally, the switching converter comprises a buck converter, a boost converter or a buck-boost converter.

[0039] Optionally, the apparatus comprises a switching converter.

[0040] According to a second aspect of the present disclosure, there is provided a method for controlling a switching converter for receiving an input voltage and for providing an output voltage, the switching converter comprising a first switch and an energy storage element, the method comprising using a controller to provide a first control signal to the first switch, the first control signal having a switching frequency, and using the controller to control the switching frequency so that the switching frequency is substantially unaffected by changes in one or more of i) the load current, ii) the equivalent series resistance of the energy storage element, and iii) the on-resistance of the first switch.

[0041] It will be appreciated that the method of the second aspect may include features set out in the first aspect and may incorporate other features described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present disclosure is described in more detail below by way of examples and with reference to the accompanying drawings, in which:

[0043] FIG. 1( a ) is a schematic diagram of a device according to a first embodiment of the present disclosure, and FIG. 1( b ) is a schematic diagram of a device according to a second embodiment of the present disclosure;

[0044] FIG. 2( a ) is a schematic diagram of a device according to a third embodiment of the present disclosure, FIG. 2( b ) is a schematic diagram of a device according to a fourth embodiment of the present disclosure, and FIG. 2( c ) is a schematic diagram of another example of the device of FIG. 2( b );

[0045] FIG. 3( a ) is a schematic diagram of a device according to a fifth embodiment of the present disclosure, FIG. 3( b ) is a schematic diagram of a buck converter to illustrate the basic theory of the buck converter, and FIG. 3( c ) is a timing diagram illustrating the operation of the buck converter of FIG. 3( b );

[0046] FIG. 4( a ) is a schematic diagram of a device according to a sixth embodiment of the present disclosure, FIG. 4( b ) is a schematic diagram of a specific embodiment of a replication module, and FIG. 4( c ) is a schematic diagram of a device according to a seventh embodiment of the present disclosure;

[0047] Figure 5 is a schematic diagram of a device according to an eighth embodiment of the present disclosure;

[0048] Figure 6 is a schematic diagram of a device according to a ninth embodiment of the present disclosure;

[0049] Figure 7 is a schematic diagram of a device according to a tenth embodiment of the present disclosure;

[0050] Figure 8 is a schematic diagram of a device according to an eleventh embodiment of the present disclosure;

[0051] Fig. 9 To show Figure 6 frequency diagrams of simulation results of a practical implementation of a device and a practical implementation of an existing system susceptible to variations in load current;

[0052] Fig.10 is a schematic diagram showing an exemplary implementation of a filter stage and a voltage buffer circuit;

[0053] Fig.11 A schematic diagram showing another exemplary implementation of a filter stage; and

[0054] Fig.12 is a schematic diagram showing another exemplary implementation of a filter stage and a voltage buffer circuit. DETAILED DESCRIPTION

[0055] DC-DC switching converters, such as buck or boost converters, can use basic constant on-time (COT) or constant off-time control. COT means that the "on-time" of the switches in the converter is fixed during operation. The switching frequency can be varied.

[0056] To stabilize the operating frequency, an advanced COT converter will adapt the on-time to the output voltage and the input voltage, so that for a buck converter, the on-time Ton is proportional to the output voltage divided by the input voltage (Vout / Vin). The duty cycle of a buck converter is D=Vout / Vin.

[0057] In known DC-DC switching converter designs, Vout will be the output voltage of the off-chip LC filter, and such voltage can be used to generate the on-time Ton. However, in the physical implementation of the system, the output voltage Vout and the input voltage Vin will be affected by the load current, the on-resistance in the power stage of the DC-DC converter, and the series resistance (DCR) of the inductor, which can be referred to as its equivalent series resistance.

[0058] Simulations of a practical implementation of a known system show that the measured switching frequency Fsw increases by approximately 10% when the load current changes from 2.5A to 10A, as presented in the following table.

[0059]

[0060] FIG. 1( a ) is a schematic diagram of an apparatus 100 including a controller 102 for a switching converter 104 according to a first embodiment of the present disclosure.

[0061] The switching converter 104 is configured to receive an input voltage Vin and provide an output voltage Vout. The switching converter 104 includes a switch 106 and an energy storage element 108.

[0062] The switching converter 104 may be, for example, a DC-DC switching converter, and may be a buck converter, a boost converter, or a buck-boost converter.

[0063] The controller 102 is configured to provide a control signal 110 to the switch 106. Based on the control signal 110, the switch 106 switches between an on-state in which the switch 106 is closed and allows current to flow, and an off-state in which the switch 106 is open and does not allow current to flow.

[0064] The control signal 110 has a switching frequency. During operation, the switch 106 receives the control signal 110 from the controller 102 and periodically couples and decouples with the energy storage element 108 based on the switching frequency of the control signal 110. The energy storage element 108 may include, for example, an inductor. The switch 106 may include a transistor, such as a split-gate field effect transistor.

[0065] The controller 102 is configured to control the switching frequency such that the switching frequency is substantially unaffected by changes in at least one of the following:

[0066] Load current

[0067] The equivalent series resistance of the energy storage element 108

[0068] On-resistance of switch 106

[0069] The controller 102 may control the switching frequency to maintain a substantially constant switching frequency regardless of changes in one or more of the aforementioned parameters.

[0070] Load current is the current provided by switching converter 104 to a load, such as a resistive element, during operation.

[0071] The equivalent series resistance of the energy storage device 108 is a parameter used to model the internal resistance of an energy storage element 108 such as a capacitor or an inductor in an electronic circuit. It represents the total resistance that exists in series with an ideal storage element.

[0072] For inductors, the equivalent series resistance represents the resistance in series with the inductor. This resistance comes from the resistance of the wire used to wind the inductor coils and any additional resistive losses in the core material. As with capacitors, the equivalent series resistance in an inductor is usually small enough to have no substantial effect on circuit operation, but it can be significant in some high-frequency or high-performance circuits.

[0073] For capacitors, equivalent series resistance refers to the resistance that exists in series with the capacitance. In real-world capacitors, there is always a certain amount of inherent resistance due to the conductive properties of the dielectric material and the leads used to connect the capacitor to the circuit.

[0074] The on-resistance of the switch 106 is the resistance when the switch 106 is in the on state.

[0075] Known control systems only consider the input voltage Vin and the output voltage Vout for controlling the switching frequency. This means that in known systems, if the load current, the equivalent series resistance of the energy storage element 108 or the on-resistance of the switch 106 changes, the switching frequency of the control signal 110 will change.

[0076] The controller 102 of the present disclosure enables control of the switching frequency such that the switching frequency is substantially unaffected by one or more of the load current, the equivalent series resistance of the energy storage element 110 , and the on-resistance of the switch 106 .

[0077] Thus, the controller 102 of the present disclosure provides an improved switching converter controller with optimized operation when compared to known systems. In the present example, the switching converter 104 is optimized to use a consistent switching frequency, ie, independent of variations in load current, for example.

[0078] It should be understood that in this example, the switching converter 104 includes a single switch. However, in other embodiments, the controller 102 can operate a switching converter having two or more switches, each of which receives a control signal. The operation of such a system will be clear to the skilled person. In such embodiments, the controller 102 can be configured to control the switching frequency associated with each control signal so that the switching frequency is substantially unaffected by one or more of the aforementioned parameters.

[0079] The controller 102 may continuously monitor the output voltage Vout of the switching converter 104 and compare the output voltage Vout (or a feedback signal dependent on the output voltage) with a reference voltage representing a desired output voltage. If there is a deviation between the output voltage (or the associated feedback signal when used) and the reference value, the controller 102 provides an appropriate control signal to adjust the operation of the converter 104 so that the output voltage Vout is closer to the desired level.

[0080] The controller 102 may employ control algorithms based on the feedback and reference values ​​to determine appropriate control signals 110. Depending on the complexity and requirements of the system, and as will be appreciated by the skilled artisan, these algorithms may be implemented using analog circuitry or digital signal processing techniques.

[0081] During operation, the control signal 110 may set the switch 106 to an on state for an on time and to an off state for an off time. The control signal 110 generated by the controller 102 defines the on time and off time of the switch 106 to control power flow and regulate the output voltage Vout.

[0082] The control signal 110 typically comprises a series of digital pulses having certain timing characteristics such as switching frequency (as previously discussed) and pulse width.

[0083] The controller 102 may be configured to control the switching frequency by setting an on-time and / or an off-time provided by the control signal 110. The controller 110 may set the on-time and / or the off-time based on one or more of the load current, the equivalent series resistance of the energy storage element 108, and the on-resistance of the switch 106, thereby controlling the switching frequency such that the switching frequency is substantially unaffected by changes in at least one of these parameters.

[0084] The controller 102 may be configured to set the on-time and / or the off-time using at least one of the following: the input voltage Vin, the output voltage Vout, the load current, the equivalent series resistance of the energy storage element 108 , and the on-resistance of the switch 106 .

[0085] 1( b) is a schematic diagram of a device 112 including a controller 102 according to a second embodiment of the present disclosure. The controller 102 may be configured to receive information about one or more of a load current, an equivalent series resistance of an energy storage element 108, and an on-resistance of a switch 106. In this example, the device 112 includes a current sensor 114 for extracting load current information and then providing the load current information to the controller 102.

[0086] 2(a) is a schematic diagram of a device 200 according to a third embodiment of the present disclosure. The device 200 includes a controller 102 for a switching converter 104. In this embodiment, the switch 106 includes a field effect transistor 202 coupled to an energy storage element 108 and receives a control signal 110 from the controller 102 during operation.

[0087] The field effect transistor 202 may be a metal oxide semiconductor FET (MOSFET). The field effect transistor 202 may be, for example, a split gate field effect transistor, and may include a control gate and a floating gate.

[0088] 2( b ) is a schematic diagram of a device 204 according to a fourth embodiment of the present disclosure. The device 204 includes a controller 102 for a switching converter 104. In this embodiment, the energy storage element 108 includes an inductor 206.

[0089] It should be understood that the inductor 206 may be a passive electronic component used in an electrical circuit to store and release energy in the form of a magnetic field, typically but not limited to being made of a coil of wire wound around a core material and having an inductance.

[0090] 2(c) is a schematic diagram of another example of device 204. In this example, switching converter 104 includes a low-side switch 203, which is turned on when switch 202 is off, and an inverter 205. It should be understood that this is a common practice in buck converter design.

[0091] 3(a) is a schematic diagram of a device 300 according to a fifth embodiment of the present disclosure. In this embodiment, the switching converter 104 comprises a buck converter including a switch 302. The switching converter 104 is coupled to an output capacitor 304. The switch 302 may correspond to the switch 203 as previously described.

[0092] Buck converters, also known as step-down converters, are a type of DC-DC switching converter that reduces voltage from a higher level to a lower level. Buck converters are widely used in electronic devices to provide a stable and regulated lower voltage required to power various components.

[0093] In an alternative embodiment, the switching converter 104 may be a boost converter, also known as a step-up converter. A boost converter is a DC-DC switching converter used to efficiently increase a voltage from a lower level to a higher level. It is widely used in various electronic applications that require a higher output voltage than the available input voltage.

[0094] In other embodiments, switching converter 104 may be a buck-boost converter.

[0095] The switching converter 104 of the apparatus 300 is used with a dual-switch gate configuration; the controller 102 is used to regulate the operation of the dual-switch gate switching converter.

[0096] The controller 102 is configured to provide a control signal 306 to the switch 302. The control signal 306 may vary at a switching frequency.

[0097] The controller 102 controls the switching of the two power semiconductor switches 202, 302 by providing control signals 110, 306 to the switching converter 104. The dual-switch gate switching converter 102 may also be referred to as a "dual active bridge" converter or a "dual bridge" converter.

[0098] In the dual-switch gate switching converter 102, there is a pair of power switches 202, 302 arranged in a bridge configuration. The pair includes a high-side switch (provided by switch 202 and connected to the input voltage Vin) and a low-side switch (provided by switch 302 and connected to ground).

[0099] The controller 102 may be configured to control the switching frequency such that the switching frequency is substantially unaffected by changes in the on-resistance of the switch 302 .

[0100] The controller 102 may be configured to set an on-time and / or an off-time of one or both of the control signals 110 , 306 based on one or more of the load current IL , the equivalent series resistance of the energy storage element 206 , the on-resistance of the switch 202 , and the on-resistance of the switch 302 .

[0101] The controller 102 may be configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in the load current, the equivalent series resistance of the energy storage element 206 , the on-resistance of the switch 202 , and the on-resistance of the switch 302 .

[0102] The controller 102 may be configured to set the on-time and / or off-time using the input voltage Vin, the output voltage Vout, the load current IL, the equivalent series resistance of the energy storage element 206 , the on-resistance of the switch 202 , and the on-resistance of the switch 302 .

[0103] FIG3( b ) is a schematic diagram of a buck converter 308 to illustrate the basic theory of a buck converter. The buck converter includes switches 310 , 312 and an inductor 314 , as well as a resistor Rind. FIG3( c ) is a timing diagram illustrating the operation of the buck converter 308 of FIG3( b ).

[0104] During Ton, the high-side switch 310 is turned on with the resistor RH and the low-side switch 312 is turned off. During Toff, the low-side switch 312 is turned on with the resistor RL and the high-side switch 310 is turned off.

[0105] In To n During this time, the voltage on the left side of the inductor (SW) is:

[0106] SW=VIN-IL*RH (1)

[0107] The voltage on the right side of the inductor (IND) is:

[0108] IND=VOUT+IL*Rind (2)

[0109] And the current in the inductor 314 will rise.

[0110]

[0111] Where IL is the average current in the inductor and L is the inductance of the inductor.

[0112] During the Toff time, since the current in the inductor cannot change direction, the voltage on the left side of the inductor (SW) is:

[0113] SW=-IL*RL (4)

[0114] The voltage on the right side of the inductor (IND) is:

[0115] IND=VOUT+IL*RL (5)

[0117] The current in the inductor will drop

[0118]

[0119] Since the buck converter operates in stable conditions, this means that the beginning of the current in the inductor and the end of the current are equal, so this makes:

[0120] Ifall=Irise(7)

[0121]

[0122] besides,

[0123]

[0124] By combining equations (8) and (9), in this embodiment, the control signal 110,

[0125] One or both of 306 provide a switching frequency Fs w It can be calculated by the following equation:

[0126]

[0127] in:

[0128] DeltaR=RH-RL (11)

[0130] Vin and Vout are the input voltage and output voltage, respectively; IL is the load current; and Ton is the on-time of the switch 202 as provided by the control signal 110. For a constant switching frequency Fs independent of changes in the load current IL, the equivalent series resistance of the switches 202, 302, and the equivalent series resistance of the inductor 206, w , if Ton is as follows, then a stable Fs will be achieved w :

[0131]

[0132] Where RH is the on-resistance of the high-side switch 202 ; R1 is the on-resistance of the low-side switch 302 ; and Rind is the DC resistance of the inductor 206 (corresponding to its equivalent series resistance).

[0133] Therefore, referring to equations (1) to (12), it can be observed that for the device 300, the switching frequency Fs can be set by considering the load current IL, the switch resistance RH, RL and the equivalent series resistance Rind of the inductor. w Using this information, the controller 102 can then provide a constant switching frequency for the switching operation regardless of changes in the load current IL. In this example, the controller 102 can receive and use information about the load current IL to set the control signals 110, 306 for the operation of the switches 202, 302.

[0134] It will be appreciated that information about the load current IL, the switch resistances RH, RL, and the equivalent series resistance Rind of the inductor may be provided as inputs to the controller 102. For example, the device 300 may include a current sensor 114 as previously discussed for detecting the load current IL.

[0135] Since switch 302 is intended to be in the on state when switch 202 is in the off state and in the off state when switch 202 is in the on state, control signal 306 may be the inversion of control signal 110, such that the on time as provided by control signal 110 corresponds to the off time provided by control signal 306. This functionality may be provided by providing control signal 110 (or a signal having properties of control signal 110) via an inverter to generate control signal 306. Alternatively, switch 302 may be of a different type than switch 202, such that the state of the control signal enabling one of switches 202, 302 has the effect of disabling the other, and vice versa - in such examples, control signals 110, 306 may be identical. It should be appreciated that the desired functionality may be provided in other ways, as understood by the skilled artisan.

[0136] It should be understood that the controller 102 may include a gate driver (not shown) for outputting the control signals 110 , 306 such that they are suitable for switching the switches 202 , 302 .

[0137] 4(a) is a schematic diagram of a device 400 according to a sixth embodiment of the present disclosure. In this embodiment, the device 400 includes a replica module 402 configured to generate a replica output voltage DVout that is substantially unaffected by changes in one or more of the load current, the equivalent series resistance of the energy storage element 108, and the on-resistance of the switch 106. The controller 102 is configured to receive the replica output voltage DVout and use the replica output voltage DVout to control the switching frequency.

[0138] The replica module 402 may be coupled to an input voltage Vin and receive a control signal 110 for generating a replica output voltage DVout.

[0139] The replica module 402 replicates the characteristics of the switching converter 104, but is not susceptible to changes in the load current IL of the switching converter 104, and / or the equivalent series resistance of the energy storage element 108, and / or the on-resistance of the switch 106, and can therefore be used to generate a replica output voltage DVout that corresponds to the ideal output voltage Vout that would occur if the operation of the switching converter 104 were not sensitive to the above parameters. Therefore, DVout can be used to set the on-time and / or off-time of the control signal 110.

[0140] In a specific example, both the replica output voltage DVout and the input voltage Vin may be used to set the on-time and / or the off-time.

[0141] The switching converter 104 may include any of the features discussed herein with respect to other embodiments of the present disclosure. For example, the switching converter 104 may be a DC-DC converter and may include a buck converter, a boost converter, or a buck-boost converter. In addition, the switching converter 104 may include a second switch such as that presented in the device 300, wherein the control signal 110 is controlled such that the switching frequency is substantially unaffected by changes in the on-resistance of the second switch.

[0142] The following examples are described with respect to a buck converter. However, in further embodiments the system may be adapted to operate with other switching converters as will be clear to the skilled person.

[0143] 4( b) is a schematic diagram of a specific embodiment of a replica module 402, which, according to the understanding of a skilled person, can implement any of the embodiments described herein. The replica module 402 includes a replica power stage 404 for replicating the characteristics of the power stage of the switching converter 104. In this example, the replica power stage 404 includes a replica switch 406 that is a "copy" of the switch 106.

[0144] By “replica” it is meant that the replica switch 406 has the same physical properties as the switch 106 , such that it will exhibit the same electrical performance as the switch 106 .

[0145] A "replica" may also refer, for example, to the case where switch 406 does not have the same physical properties as switch 106, but rather has properties that result in electrical characteristics of switch 406 that are scaled relative to the electrical properties of switch 106 and are thus still sufficient to generate a suitable replica voltage DVout. For example, the scaling may be compensated in the generation of the on-time and / or the off-time.

[0146] The replica module 402 may include a filter stage 408 for filtering the replica output voltage DVout, for example, to filter out unwanted frequency components. The filter stage 408 may include a component or combination of components for attenuating frequencies, thereby reducing unwanted noise, ripples, or harmonics in the replica output voltage DVout.

[0147] The filter stage 408 may include an LC filter including at least one inductor and at least one capacitor forming an LC filter, thereby providing filtering characteristics and reducing voltage ripples and harmonics in the replica output voltage DVout.

[0148] The replica module 404 may additionally include a voltage buffer circuit 410 .

[0149] FIG4( c) is a schematic diagram of a device 410 according to a seventh embodiment of the present disclosure. In this embodiment, the switching converter 104 includes a buck converter. The controller 102 is configured to use the input voltage Vin and the replica output voltage DVout to set the on-time and / or off-time. The on-time set by the controller can be proportional to the replica output voltage DVout divided by the input voltage Vin.

[0150] In summary, replication module 402 may refer to a “duplication” or “replication” of one or more semiconductor power switches and associated components to create multiple identical power stages within a system. Replication module 402 may operate independently and in parallel with switching converter 104 .

[0151] The replica module 402 avoids the need to directly measure the load current IL. In particular, it generates a replica output voltage DVout that corresponds to the output voltage Vout but is independent of the load current IL of the switching converter 104.

[0152] Figure 5 4 is a schematic diagram of a device 500 according to an eighth embodiment of the present disclosure. In this embodiment, the replica power stage 404 includes a replica switch 406 as a “copy” of the switch 202 and a replica switch 502 as a “copy” of the switch 302 .

[0153] Instead of sensing the load current IL to compensate for the voltage drift on Vout, this embodiment uses a second power stage 404 without any DC current passing through it. The filtered output DVout can be used to generate the on-time Ton.

[0154] Figure 6Schematic diagram of a device 600 according to a ninth embodiment of the present disclosure. In this embodiment, the filter stage 408 includes resistors 602a, 602b, 602c, 602d, 602e, 602f and capacitors 604a, 604b. In this embodiment, the buffer circuit 410 includes a differential amplifier 606 and resistors 608a, 608b, 608c.

[0155] In this example, the replica power stage 404 and the filter stage 408 can be implemented “on chip”. The output of the filter stage 408 will be used to generate the on-time Ton using the controller 102. Since there is no high load current passing through the replica power stage 404, the frequency of the entire DC-DC converter 104 will not be affected by the on-resistance in the main power stage of the converter 104, the equivalent series resistance (DCR) of the inductor, and the load current IL.

[0156] Figure 7 Schematic diagram of a device 700 according to a tenth embodiment of the present disclosure. In this embodiment, the replica module 402 includes resistors 702a, 702b, capacitors 704a, 704b, a summing circuit 706, a current source 708 and a transistor 710. “DCR” represents the equivalent series resistance of the inductor 206.

[0157] Figure 8 8 is a schematic diagram of a device 800 according to the eleventh embodiment of the present disclosure. In this embodiment, the replica module 402 includes resistors 802 a and 802 b and capacitors 804 a and 804 b as well as a current source 708 and a transistor 710 .

[0158] Fig. 9 To show Figure 6 Frequency graphs of simulation results for an actual implementation of device 600 (trace 902) and an actual implementation of an existing system susceptible to variations in load current (trace 904).

[0159] It can be observed that the apparatus 600 of the present disclosure exhibits smaller variations in switching frequency as load current varies when compared to prior art systems.

[0160] Fig.10 4 is a schematic diagram showing an exemplary implementation of the filter stage 408 and the voltage buffer circuit 410. The filter includes switches 1000, 1002 and a resistor 1004; and the buffer circuit 410 includes switches 1006, 1008, an amplifier 1010, capacitors 1012, 1014 and a resistor 1016.

[0161] Fig.11is a schematic diagram showing another example implementation of a filter stage 408, which includes switch cells 1100, 1102, a transistor 1104, and resistors 1106, 1108, 1110. The switch cells 1100, 1102 create a replicated SW signal as V1.

[0162] Fig.12 4 is a schematic diagram showing another exemplary implementation of the filter stage 408 and the voltage buffer circuit 410. The filter stage 408 acts as an RC filter; and the buffer circuit 410 is a CMOS voltage buffer. In the buffer circuit 410, two series-connected RC filters filter the output of the filter stage 408 to V3, which can be a replica version of Vout in equation (12). The CMOS voltage buffer is designed to improve the driving performance of V3.

[0163] Various improvements and modifications may be made to the above without departing from the scope of the present disclosure.

Claims

1. A device comprising a controller for a switching converter, the switching converter for receiving an input voltage and for providing an output voltage, the switching converter comprising a first switch and an energy storage element, the controller being configured to: providing a first control signal to the first switch, the first control signal having a switching frequency; and Controlling the switching frequency such that the switching frequency is not substantially affected by changes in one or more of: i) Load current; ii) an equivalent series resistance of the energy storage element; and iii) the on-resistance of the first switch.

2. The device according to claim 1, wherein the controller is configured to: The switching frequency is controlled to maintain a substantially constant switching frequency regardless of changes in one or more of: i) the load current; ii) the equivalent series resistance of the energy storage element; and iii) the on-resistance of the first switch.

3. The apparatus according to claim 1, wherein: The first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time; and The controller is configured to: The on-time and / or the off-time are set based on one or more of the following: i) the load current; ii) the equivalent series resistance of the energy storage element; as well as iii) the on-resistance of the first switch; The switching frequency is thereby controlled such that the switching frequency is substantially unaffected by the change.

4. The apparatus according to claim 1, wherein: The switching converter comprises a buck converter, the buck converter comprising the first switch and the second switch, wherein the energy storage element comprises an inductor; and The controller is configured to provide a second control signal to the second switch, the control signal having the switching frequency. 5 . The apparatus of claim 4 , wherein the controller is configured to control the switching frequency such that the switching frequency is substantially unaffected by a change in an on-resistance of the second switch.

6. The apparatus according to claim 5, wherein: The first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time; and The controller is configured to: The on-time and / or the off-time are set based on the load current, the equivalent series resistance of the energy storage element, the on-resistance of the first switch, and the on-resistance of the second switch, thereby controlling the switching frequency so that the switching frequency is substantially unaffected by the change.

7. The apparatus of claim 6, wherein the controller is configured to control the switching frequency to maintain a substantially constant switching frequency regardless of changes in the load current, the equivalent series resistance of the energy storage element, the on-resistance of the first switch, and the on-resistance of the second switch.

8. The device of claim 7, wherein the controller is configured to set the on-time and / or off-time using the input voltage, the output voltage, the load current, the equivalent series resistance of the energy storage element, the on-resistance of the first switch, and the on-resistance of the second switch.

9. The device according to claim 8, wherein the on-time set by the controller is is proportional to, wherein Vin is the input voltage, IL is the load current, RH is the on-resistance of the first switch, RL is the on-resistance of the second switch, and Rind is the equivalent series resistance of the energy storage element.

10. The device according to claim 1, comprising: A replica module configured to generate a replica output voltage that is substantially unaffected by changes in one or more of: i) the load current; ii) the equivalent series resistance of the energy storage element; as well as iii) the on-resistance of the first switch; wherein: The controller is configured to receive the replica output voltage and use the replica output voltage to control the switching frequency.

11. The apparatus of claim 10, wherein: The first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time; and The controller is configured to use the replica output voltage to set the on-time and / or the off-time, thereby controlling the switching frequency such that the switching frequency is substantially unaffected by the variation.

12. The apparatus of claim 10, wherein: The switching converter comprises a buck converter, the buck converter comprising the first switch and the second switch, wherein the energy storage element comprises an inductor; and The controller is configured to provide a second control signal to the second switch, the control signal having the switching frequency.

13. The apparatus of claim 12, wherein the controller is configured to control the switching frequency such that the switching frequency is substantially unaffected by a change in an on-resistance of the second switch.

14. The apparatus of claim 13, wherein: The first control signal is configured to set the first switch to an on state for an on time and to an off state for an off time; and The controller is configured to: The on-time and / or the off-time are set using the replica output voltage, thereby controlling the switching frequency such that the switching frequency is substantially unaffected by the variation. 15 . The device of claim 14 , wherein the controller is configured to set the on-time and / or off-time using the input voltage and the replica output voltage.

16. The apparatus of claim 15, wherein the on-time set by the controller is proportional to the replica output voltage divided by the input voltage.

17. The apparatus of claim 10, wherein the replica module comprises a replica power stage including a replica first switch.

18. The apparatus of claim 17, wherein the replica module comprises a filter stage coupled to the replica power stage.

19. The apparatus of claim 18, wherein the replica module comprises a voltage buffer coupled to the filter stage and configured to provide the replica output voltage.

20. A method for controlling a switching converter receiving an input voltage and for providing an output voltage, the switching converter comprising a first switch and an energy storage element, the method comprising: Using a controller to provide a first control signal to the first switch, the first control signal having a switching frequency; and The switching frequency is controlled using the controller such that the switching frequency is not substantially affected by changes in one or more of the following: i) Load current; ii) an equivalent series resistance of the energy storage element; and iii) the on-resistance of the first switch.

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