N-bit digital-to-analog converter and mixed signal microcontroller

Abstract

The invention provides an N-bit digital-to-analog converter, which has an output voltage range between a minimum output voltage and a maximum output voltage, and is used for receiving digital data as an input and providing an output voltage as an output according to the digital data. The N-bit digital-to-analog converter comprises at least one register, an evaluation logic module and a converter. The register includes an output data register having at least N bits and M enhancement bits for storing digital data. The evaluation logic module is used for providing a binary evaluation signal derived from the digital data. The converter is used for receiving a binary evaluation signal, can access the output data register and is used for providing an output signal according to the output data register and the received binary evaluation signal.

Description

Technical Field

[0001] The present invention relates to a digital-to-analog converter and a mixed-signal microcontroller, and more particularly to an N-bit digital-to-analog converter and a mixed-signal microcontroller suitable for current-mode control of a switched-mode power supply. Background Art

[0002] In the prior art, slope compensation is often used to avoid subharmonic oscillations during the current mode control of a switch mode power supply. It is known that for peak current mode control of a switch mode power supply, if there is no proper compensation, subharmonic oscillations will occur when the switch duty cycle of the switch mode power supply is greater than 50%. For valley current mode control of a switch mode power supply, if there is no proper compensation, subharmonic oscillations will occur when the switch duty cycle of the switch mode power supply is less than 50%.

[0003] Both analog and digital current mode control are well known in the art. Switched mode power supplies contain analog components, whereas for digital current mode control mixed signal electronics are required that can process signals from both the analog and digital domains. Typically, in the prior art an analog current mode control scheme is first developed and a digital current mode control scheme is obtained by appropriately discretizing the developed analog current mode control scheme. When converting from continuous time to discrete time, a bilinear transformation may be used, for example. Thus, the digital signal used in digital current mode control is typically an analog quantity represented in digital form.

[0004] In switch mode power supplies, the actual numerical range of physical quantities such as current and voltage is mostly limited to a narrow numerical range, while the numerical range can be expanded in analog current mode control and digital current mode control. In the prior art, the resolution of the digital-to-analog converter used in the digital current mode control scheme is mainly determined by the output voltage range, the actual range of the encoded physical quantity and the number of available bits. Since not all available bits are used to represent the narrow numerical range, the use of these digital-to-analog converters will correspond to the narrow numerical range and reduce the resolution within the actual required range. The reduction in resolution will cause the effect of digital current mode control to be worse than that of the basic current mode control scheme.

[0005] Another disadvantage of the existing digital-to-analog converter is that it may not be suitable for current mode control of a switch mode power supply with slope compensation when a current sensor with a voltage offset is used. Summary of the invention

[0006] The purpose of the present invention is to provide a digital-to-analog converter that can solve at least some of the problems of existing digital-to-analog converters. Specifically, the present invention provides a mixed-signal microcontroller and a digital-to-analog converter for current-mode control of a switch-mode power supply.

[0007] According to one aspect of the present invention, an N-bit digital-to-analog converter is provided, which has an output voltage range between a minimum output voltage and a maximum output voltage, wherein N is a positive integer, and the N-bit digital-to-analog converter is used to receive digital data as input and provide an output voltage as output according to the digital data. The N-bit digital-to-analog converter comprises:

[0008] At least one register, including an output data register and M enhanced bits, wherein the output data register has at least N bits, M is a positive integer, and the N-bit digital-to-analog converter is used to store the received digital data in the output data register and the M enhanced bits;

[0009] an evaluation logic module for providing at least one binary evaluation signal derived from the digital data stored in the output data register and the M enhancement bits, each binary evaluation signal comprising a first binary evaluation signal value or a second binary evaluation signal value; and

[0010] The converter is used for receiving the binary evaluation signal, wherein the converter can access the output data register and is used for providing an output signal according to the output data register and the received binary evaluation signal.

[0011] The N-bit digital-to-analog converter is used to map a digital input value to an analog output value, wherein the analog output value is within an output voltage range between a minimum output voltage and a maximum output voltage. For example, the output voltage range can be between ground and a reference voltage V REF between, or at a negative reference voltage -V REF and reference voltage V REF The N-bit digital-to-analog converter is used to map the N-bit encoded digital signal into the output voltage range (for example, by evenly distributing 2 N possible N-bit coded digital signals), where the output voltage range may be, for example, between 0V and The actual output voltage is provided by a converter of an N-bit digital-to-analog converter, wherein the converter may, for example, include an R-2R ladder network for mapping the digital signal into an analog value. In addition to the R-2R ladder network, the converter may also use different methods known in the prior art for mapping the digital signal into an analog output voltage.

[0012] The N-bit digital-to-analog converter includes at least one register, wherein the register includes an output data register having at least N bits and M enhancement bits. As another example of a possible register, the N-bit digital-to-analog converter may include a shift register. The N-bit digital-to-analog converter may include an input pin and receive serial input data through the input pin, and the serial input data may include digital data as input. In addition to the digital data, the serial input data may also include further information for controlling the operation of the N-bit digital-to-analog converter. The N-bit digital-to-analog converter may also include another input pin and receive a clock signal through it, wherein the clock signal may determine the time of the N-bit digital-to-analog converter. When receiving the serial input data, the N-bit digital-to-analog converter first stores the received serial input data in the shift register, wherein the N-bit digital-to-analog converter may, for example, move the received serial input data to the shift register at each rising edge of the clock signal. Furthermore, for example, by other trigger signals received by the N-bit digital-to-analog converter through other dedicated input pins, the data stored in the shift register may be stored in the output data register and the M enhancement bits. Of course, in other implementations, the received digital data may be moved to the output data register and the M enhanced bits in other feasible ways.

[0013] The at least one register may also include an enhancement register different from the output data register, wherein the enhancement register may include M enhancement bits, or the output data register may include M enhancement bits, i.e., the output data register includes at least N+M bits. Since the digital data in the enhancement register may change (e.g., increase or decrease) independently of the digital data in the output data register, providing an enhancement register that is different from and independent of the output data register may provide more freedom in data processing. However, in both scenarios, the output data register and the M enhancement bits provide space for storing binary data for computational processing by the evaluation logic module of the N-bit digital-to-analog converter. The output data register and the M enhancement bits allow computational processing to be performed on an internal representation with a larger range of values ​​than the range encoded by the N bits converted to the output voltage by the converter.

[0014] The output data register and the M enhancement bits can be configured on the same side, and the converter can be configured on the other side, so that the digital data stored in the output data register and the M enhancement bits will not be directly converted into an analog output voltage by the converter. On the contrary, at least one register of the N-bit digital-to-analog converter may, for example, include a converter register with N bits, wherein the converter can directly operate the converter register, and the binary data stored in the converter register can be used to turn on or off the switch of the R-2R ladder network of the converter. The binary data stored in the converter register depends on the digital data stored in the output data register and the binary evaluation signal provided by the evaluation logic module. In the case of setting this converter register, the converter may include a control logic module, wherein the control logic module is used to write binary data into the converter register according to the binary evaluation signal and the digital data stored in the output data register.

[0015] Alternatively, the converter can operate directly on the digital data stored in the output data register, i.e., without setting the converter register. In this case, the converter includes a control logic module, wherein the control logic module takes into account both the N-bit digital data stored in the output data register and the binary evaluation signal when controlling the switches of the R-2R ladder network of the converter.

[0016] Each binary evaluation signal theoretically corresponds to a binary decision, i.e., whether the digital data stored in the output data register and the M enhancement bits satisfy a specific attribute. For example, a possible binary decision is that the stored digital data is less than or greater than a threshold value. Each binary evaluation signal may have two possible binary evaluation signal values, one of which indicates that the stored digital data does not satisfy the attribute, and the other indicates that the stored digital data satisfies the attribute. The attribute may be memoryless, i.e., whether the digital data processed by the evaluation logic module satisfies the corresponding attribute may be independent of whether the previously stored digital data satisfies the corresponding attribute. In addition, the evaluation logic module may also adopt a time-dependent attribute, i.e., whether the digital data processed by the evaluation logic module satisfies the corresponding attribute may depend on whether the previously stored digital data satisfies the corresponding attribute. In order to be able to handle such a time-dependent attribute, the N-bit digital-to-analog converter may include an internal storage device, wherein the internal storage device is used to store the binary evaluation signal.

[0017] Advantageously, the proposed N-bit digital-to-analog converter can receive digital data as input, and the digital data may not be represented by N bits, wherein the N bits together with the output voltage range define the output resolution of the N-bit digital-to-analog converter. However, via the binary evaluation signal, information about the received digital data can be determined and possibly used to adjust the output voltage of the N-bit digital-to-analog converter.

[0018] In an N-bit digital-to-analog converter of an embodiment of the present invention, the minimum output voltage and the maximum output voltage depend on a reference voltage provided to the N-bit digital-to-analog converter.

[0019] In an N-bit DAC of one embodiment of the present invention, the number of enhancement bits is adjustable. Advantageously, the range of digital data received as input by the N-bit DAC is also adjustable.

[0020] In an N-bit digital-to-analog converter of one embodiment of the present case, each binary evaluation signal corresponds to a threshold value, and the evaluation logic module is used to provide a binary evaluation signal by comparing the digital data stored in the output data register and the M enhancement bits with the threshold value, and the evaluation logic module sets the binary evaluation signal to a first binary evaluation signal value or a second binary evaluation signal value according to the comparison result.

[0021] In an N-bit digital-to-analog converter of one embodiment of the present invention, the output data register includes M enhancement bits, and the M enhancement bits are consecutively appended after the N bits, so that the output data register includes a total of N+M bits for storing digital data. Therefore, the maximum value stored in the N+M bits is 2 N+M -1.

[0022] In an N-bit digital-to-analog converter of an embodiment of the present invention, the evaluation logic module is used to provide a first binary evaluation signal, the first binary evaluation signal corresponds to a first threshold value, and the first threshold value is adjustable or equal to 2 N The converter is used to store the digital data in the output data register and the M enhancement bits when the digital data is greater than the adjustable first threshold or 2 N -1, provides the value corresponding to the adjustable first threshold or 2 N The converter is also used to store the digital data in the output data register and the M enhancement bits less than or equal to the adjustable first threshold or 2 N When -1, the output voltage is provided according to the digital data.

[0023] In an N-bit digital-to-analog converter of an embodiment of the present invention, the evaluation logic module is used to provide a second binary evaluation signal, the second binary evaluation signal corresponds to a second threshold value, the second threshold value is adjustable and is less than the first threshold value. The converter is used to provide an output voltage corresponding to the second threshold value when the digital data stored in the output data register and the M enhancement bits is less than the adjustable second threshold value. The converter is also used to provide an output voltage corresponding to the digital data when the digital data stored in the output data register and the M enhancement bits is greater than or equal to the adjustable second threshold value.

[0024] In an N-bit digital-to-analog converter of an embodiment of the present invention, the register includes an enhancement register, and the enhancement register includes the aforementioned M enhancement bits.

[0025] According to another aspect of the present invention, there is provided a mixed signal microcontroller for current mode control of a switch mode power supply, comprising:

[0026] A compensation control logic module for providing a series of digital compensation control values ​​derived from a voltage sensing signal, wherein the voltage sensing signal corresponds to a power supply output voltage of the switch mode power supply;

[0027] A slope compensation logic module for providing a series of digital slope compensation values, wherein the series of digital slope compensation values ​​are suitable for a switch mode power supply;

[0028] Any of the aforementioned N-bit digital-to-analog converters, wherein the N-bit digital-to-analog converter is used to receive a series of digital compensation control values ​​and a series of digital slope compensation values ​​as inputs, and provide a voltage control signal as output;

[0029] a comparator for comparing the voltage control signal with a voltage value corresponding to a current sensing signal and providing a comparator voltage signal as an output, wherein the current sensing signal corresponds to a current flowing through the switch mode power supply; and

[0030] The drive control logic module is used to receive the comparator voltage signal as input and provide a drive signal for the switch of the switch mode power supply as output.

[0031] Current mode control is a well-known technique for controlling switch mode power supplies, which may be peak current mode control, valley current mode control or analog current mode control. In current mode control of switch mode power supplies, the occurrence of subharmonic oscillations is a known problem, which is manifested in alternating wide pulses and narrow pulses. To prevent the occurrence of subharmonic oscillations, the available prior art is slope compensation. Current mode control is generally implemented as analog current mode control or digital current mode control. The mixed signal microcontroller proposed in this case is designed for digital current mode control.

[0032] The mixed signal microcontroller is used to control the switching action of the switch in the switch mode power supply through its driver control logic module. To this end, the mixed signal microcontroller may include a pulse width modulation controller. For example, if the switch mode power supply is a buck converter, the ratio of the power supply output voltage of the buck converter to its input voltage ideally corresponds to the duty cycle of the switch operation of the buck converter. Assuming that the buck converter does not include a second switch for synchronous rectification, but only includes a diode, a single switch of the buck converter can be controlled by the mixed signal microcontroller. This switch is periodically turned on at the switching frequency so that current flows through the switch. Once the switch is turned on, the current flowing through the inductor of the buck converter begins to rise. In each switching cycle, the mixed signal microcontroller is used to determine the time point when the switch should be turned off, and when the switch is turned off, the current flowing through the inductor of the buck converter begins to decrease. More generally, for other types of switch mode power supplies, the mixed signal microcontroller can periodically turn on the switch of the switch mode power supply in each switching cycle, and then turn off the switch.

[0033] During steady-state operation of the switch-mode power supply, the slope compensation logic module can provide a digital slope compensation value in the form of a periodically repeated compensation ramp signal, wherein the slope compensation period of the compensation ramp signal should ideally be close to the switching period of the switch-mode power supply. Typically, the type of slope compensation used (parameters that may need to be set include but are not limited to the height of the compensation ramp signal, the number of steps in each slope compensation period, the rising slope or falling slope used, the duration of the slope compensation period, etc.) depends on the type of switch-mode power supply, the mode of operation of the switch-mode power supply, and the type of current mode control used. In addition, the specific architecture of the slope compensation logic module can be known from the prior art in the field and will not be repeated here.

[0034] For example, for a buck converter using analog peak current mode control, the slope of the analog compensation signal may be set based on the falling slope of the current flowing through the inductor of the buck converter, that is, the slope of the analog compensation signal may be proportional to the ratio of the power supply output voltage (i.e., the output voltage of the buck converter) and the inductance value of the inductor of the buck converter. Similarly, for a boost converter using analog peak current mode control, the slope of the analog compensation signal may be set to be proportional to the ratio of (i) the difference between the power supply output voltage (i.e., the output voltage of the boost converter) and the input voltage of the boost converter and (ii) the inductance value of the inductor of the boost converter. Similarly, for a buck-boost converter using analog peak current control, the slope of the analog compensation signal may be set to be proportional to the ratio of the power supply output voltage (i.e., the output voltage of the buck-boost converter) and the inductance value of the inductor of the buck-boost converter. In summary, for a buck converter, a boost converter, and a buck-boost converter, when an analog peak current mode control is adopted, the slope of the compensation signal can be set based on the falling slope of the current flowing through the inductor of the converter. In addition, when the buck converter, the boost converter, or the buck-boost converter is controlled, for example, with an analog valley current mode control, the slope of the compensation signal can be set based on the rising slope of the current flowing through the inductor of the converter.

[0035] For digital current mode control, the slope compensation logic module does not provide the aforementioned analog compensation signal, but instead provides digital slope compensation values ​​with the same effect, and these digital slope compensation values ​​are subtracted or added to the digital compensation control values. The digital compensation control values ​​can be provided by the compensation control logic module at a rate corresponding to the switching frequency of the switch mode power supply. In the case where the slope compensation period is less than or equal to the switching period, the sequence of steps in each slope compensation period may be provided at a higher frequency than the switching frequency, and the corresponding clock signal is also provided to the N-bit digital-to-analog converter.

[0036] For example, in the case where the switch-mode power supply is a buck converter and the mixed-signal microcontroller is configured to perform digital peak current mode control, the N-bit digital-to-analog converter of the mixed-signal microcontroller performs the following actions in each switching cycle. First, at the beginning of the switching cycle, one of the series of digital compensation control values ​​is provided to the N-bit digital-to-analog converter and stored in the output data register and the M enhancement bits. Then, before the next digital compensation control value is provided to the N-bit digital-to-analog converter, the stored digital compensation control value will be subtracted from each digital slope compensation value in sequence. Therefore, the stored digital compensation control value will gradually decrease.

[0037] The N-bit digital-to-analog converter provides a voltage control signal as an output.

[0038] Continuing with the example of the switch mode power supply being a buck converter and the mixed signal microcontroller using digital peak current mode control, the comparator of the mixed signal microcontroller is used to compare the current sensing signal with the voltage control signal. In this example, the current sensing signal corresponds to the peak value of the current flowing through the inductor of the buck converter. In order to obtain the current sensing signal, a resistor or a current transformer may be used, for example. The current sensing signal may be provided to the mixed signal microcontroller as an input. Furthermore, based on the comparison result (i.e., the comparator voltage signal), the drive control logic module of the mixed signal microcontroller may determine the drive signal for driving the switch of the buck converter.

[0039] Under typical operating conditions of a buck converter, boost converter, or buck-boost converter, for example, using analog peak current mode control, the current sensing signal may be limited to a range narrower than the possible value range of the analog slope compensation signal within one switching cycle. Therefore, the N-bit digital-to-analog converter of the mixed-signal microcontroller can be implemented as follows: the N bits of the N-bit digital-to-analog converter do not represent the possible value range of the analog compensation signal within one switching cycle, but represent the narrower range of the current sensing signal, and the N+M bits provided by the output data register and the M enhancement bits jointly represent the possible value range of the analog compensation signal within one switching cycle. Thereby, the N-bit digital-to-analog converter of the mixed-signal microcontroller proposed in the present case can improve the resolution within the narrower value range of the current sensing signal, wherein the narrower value range is related to the subsequent comparison of the voltage control signal and the current sensing signal; while retaining the ability to process the possible value range of the analog compensation signal within one switching cycle. If a conventional N-bit DAC is used instead of the proposed N-bit DAC, the resolution within the relevant range of current mode control will be lower because N bits will be used to represent the possible value range of the analog compensation signal within a switching cycle.

[0040] For example, for a buck converter using analog peak current mode control, the evaluation logic module of the N-bit digital-to-analog converter can provide a binary evaluation signal. If the digital data currently stored in the output data register and the M enhancement bits (corresponding to the gradually decreasing digital compensation control value) is greater than 2 N -1, the N-bit digital-to-analog converter can provide the maximum output voltage as the output voltage. If the digital data currently stored in the output data register and the M enhancement bits is less than or equal to 2 N -1, the converter of the N-bit digital-to-analog converter can provide a voltage within the output voltage range corresponding to the currently stored digital data.

[0041] The power supply output voltage of the switch mode power supply can be provided to a mixed signal microcontroller via a voltage divider, and the mixed signal microcontroller can include an analog-to-digital converter, wherein the analog-to-digital converter samples a portion of the power supply output voltage provided by the voltage divider, and then the sampled value can be provided to a digital filter, which in turn outputs a digital compensation control value.

[0042] By using a mixed signal microcontroller for current mode control of a switch mode power supply, it is advantageous to use a current sensor to sense the current in the switch mode power supply, wherein the current sensor has an output voltage offset. In addition, by using a mixed signal microcontroller for current mode control of the switch mode power supply, it is also advantageous to improve the protection of the switch mode power supply in the event of a rapid increase in current in the switch mode power supply.

[0043] In a mixed signal microcontroller of one embodiment of the present case, the mixed signal microcontroller further includes an analog-to-digital converter and / or a drive control logic module, wherein the analog-to-digital converter is used to receive a voltage sensing signal as an input and provide a digital voltage sensing signal to the compensation control logic module as an output; the drive control logic module includes a pulse width modulation controller.

[0044] In a mixed signal microcontroller of one embodiment of the present case, a series of digital slope compensation values ​​is a periodically repeated compensation ramp signal, and for each digital compensation control value, the mixed signal microcontroller is used to store the digital compensation control value in an output data register and M enhancement bits, and before storing subsequent digital compensation control values ​​in the output data register and M enhancement bits, the stored digital compensation control value is adjusted by adding or subtracting the digital slope compensation value in a period of the compensation ramp signal from the stored digital compensation control value.

[0045] In a mixed signal microcontroller according to an embodiment of the present invention, an evaluation logic module of an N-bit digital-to-analog converter is used to provide a binary evaluation signal after adjusting the stored digital compensation control value.

[0046] The binary evaluation signal may be provided after a series of digital compensation control values ​​have been adjusted, rather than after each adjustment of the stored digital compensation control value.

[0047] In a mixed signal microcontroller of an embodiment of the present case, the mixed signal microcontroller is suitable for peak current mode control, and the slope compensation logic module is used to provide a compensation ramp signal, the slope of the compensation ramp signal corresponds to the falling slope of the inductor current flowing through the inductor of the switch mode power supply.

[0048] In a mixed signal microcontroller of an embodiment of the present invention, the mixed signal microcontroller is suitable for valley current mode control, and the slope compensation logic module is used to provide a compensation ramp signal, and the slope of the compensation ramp signal corresponds to the rising slope of the inductor current flowing through the inductor of the switch mode power supply. The register of the N-bit digital-to-analog converter includes an enhancement register, and the enhancement register includes the aforementioned M enhancement bits.

[0049] Since the data in the enhancement register can be changed independently of the data in the output data register, the N-bit digital-to-analog converter including the independent enhancement register in the present case can improve the degree of freedom of data processing.

[0050] In a mixed signal microcontroller of an embodiment of the present invention, the mixed signal microcontroller is configured to be suitable for current mode control of a buck converter, current mode control of a boost converter, or current mode control of a buck-boost converter.

[0051] According to the subsequent detailed description and complete claims, other embodiments of the present invention and the combination of various technical features can be further understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 FIG. 4 is a schematic diagram of the structure of an N-bit digital-to-analog converter according to an embodiment of the present invention.

[0053] Figure 2 A switch mode power supply and a mixed signal microcontroller for current mode control of the switch mode power supply are illustrated.

[0054] Figure 3A and Figure 3B Two embodiments of the register of the N-bit digital-to-analog converter of the present invention are illustrated.

[0055] Figure 4 The relationship between the input and output of an N-bit digital-to-analog converter is illustrated.

[0056] Figure 5A , Figure 5B and Figure 5C An example implementation of using a threshold in an N-bit digital-to-analog converter is shown.

[0057] Fig. 6A and Figure 6B Schematic diagram of protecting a switch-mode power supply by using a threshold in an N-bit digital-to-analog converter.

[0058] The reference numerals are described as follows:

[0059] 1: N-bit digital-to-analog converter

[0060] 2: Digital Data

[0061] 3: Output voltage

[0062] 4: Output data register

[0063] 5: Enhanced bit

[0064] 6: Evaluation Logic Module

[0065] 7: Converter

[0066] 8: Reference voltage

[0067] 9: Mixed-Signal Microcontroller

[0068] 10: Switching Mode Power Supply

[0069] 11: Compensation control logic module

[0070] 12: Voltage sensing signal

[0071] 13: Power supply output voltage

[0072] 14: Slope compensation logic module

[0073] 15: Comparator

[0074] 16: Current sensing signal

[0075] 17: Drive control logic module

[0076] 18: Analog-to-digital converter

[0077] 19: Voltage Divider

[0078] 20: Current sensor

[0079] 21: Bit

[0080] 22: Enhanced Bit

[0081] 23: Enhanced register

[0082] 25: Pulse width modulation signal

[0083] 26: Offset

[0084] 27: High current

[0085] In the various drawings, the same elements are denoted by the same reference numerals. DETAILED DESCRIPTION

[0086] Some typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different aspects without departing from the scope of the present invention.

[0087] Figure 1FIG. 1 is a schematic diagram of the structure of an N-bit digital-to-analog converter 1 according to an embodiment of the present invention. In general, the N-bit digital-to-analog converter 1 is used to receive digital data 2 as input and provide an output voltage 3 as output. The N-bit digital-to-analog converter 1 includes an N-bit output data register 4 and M enhancement bits 5. Figure 1 In the figure, the M enhancement bits 5 are shown separated from the output data register 4, but in reality the M enhancement bits 5 can be provided by the output data register 4 itself or by a separate enhancement register. The output voltage range of the N-bit digital-to-analog converter 1 depends on the reference voltage 8, and the N bits in the output data register 4 can represent the output voltage range.

[0088] When receiving digital data 2 as input, the N-bit digital-to-analog converter 1 is used to store the digital data 2 in the output data register 4 and the M enhancement bits. The N-bit digital-to-analog converter 1 also includes an evaluation logic module 6, wherein the evaluation logic module 6 can operate on at least one register (e.g., the output data register 4 and the M enhancement bits 5). The evaluation logic module 6 is used to provide at least one binary evaluation signal derived from the digital data 2 stored in the output data register 4 and the M enhancement bits 5.

[0089] The output voltage 3 can be provided by the converter 7 of the N-bit digital-to-analog converter 1 . The converter 7 can, for example, comprise an R-2R ladder network. To generate the output voltage 3 , the converter 7 takes into account the binary evaluation signal provided by the evaluation logic module 6 in addition to the N bits of the output data register 4 .

[0090] Figure 2 The switch mode power supply 10 and the mixed signal microcontroller 9 for current mode control of the switch mode power supply 10 are illustrated. The switch mode power supply 10 may be implemented as a buck converter, a boost converter or a buck-boost converter, for example. Figure 2 In the illustrated embodiment, the mixed signal microcontroller 9 controls the switch mode power supply 10 by appropriately turning on and off switches in the switch mode power supply 10 .

[0091] At Figure 2 In the figure, the voltage source of the switch mode power supply 10 is not specifically shown, but is actually included in the schematic block of the switch mode power supply 10. The power output voltage 13 of the switch mode power supply 10 is provided to the voltage divider 19, wherein the voltage divider 19 is used to make the voltage range of the power output voltage 13 conform to the voltage range accepted by the analog-to-digital converter 18 of the mixed signal microcontroller 9. Thereby, the mixed signal microcontroller 9 receives a voltage sensing signal 12.

[0092] In order to perform current mode control of the switch mode power supply 10, the mixed signal microcontroller 9 receives a voltage sensing signal 12 and a current sensing signal 16, wherein the current sensing signal 16 is generated based on the current flowing through the switch mode power supply 10. The current sensing signal 16 can be sensed by a current sensor 20, wherein the current sensor 20 can include, for example, a resistor or a current transformer.

[0093] like Figure 2 As shown, there is a current control inner loop and a voltage control outer loop in the N-bit digital-to-analog converter 1. In the voltage control outer loop, the voltage sensing signal 12 is first sampled by the analog-to-digital converter 18, and then digitally filtered by the compensation control logic module 11. The compensation control logic module 11 can, for example, adopt a two-pole two-zero compensator. In order to avoid subharmonic oscillation, the slope compensation logic module 14 provides a series of digital slope compensation values, wherein the series of digital compensation control values ​​provided by the compensation control logic module 11 will be respectively subtracted or added to the series of digital slope compensation values ​​provided by the slope compensation logic module 14. The numerical design method of the digital slope compensation value is the prior art in the art, so it will not be repeated here.

[0094] Then, the N-bit digital-to-analog converter 1 of the mixed-signal microcontroller 9 receives digital data as input, wherein the digital data is formed by the difference or sum of a series of digital compensation control values ​​and digital slope compensation values. Next, the N-bit digital-to-analog converter 1 provides an output voltage to the comparator 15 of the mixed-signal microcontroller 9. In addition, the comparator 15 also receives the current sensing signal 16 as input. The comparator 15 and the subsequent drive control logic module 17 form a current control inner loop. The drive control logic module 17 generally includes a pulse width modulation controller. For example, when the current sensing signal 16 is equal to the output voltage provided by the N-bit digital-to-analog converter 1, the pulse width modulation controller can turn off a switch in the switch mode power supply 10.

[0095] Figure 3A and Figure 3B Two embodiments of the register of the N-bit digital-to-analog converter of the present invention are illustrated.

[0096] exist Figure 3A In the embodiment, the output data register 4 includes N bits 21 and M enhancement bits 22, and the N bits 21 can be converted into the output voltage 3 by the converter 7 of the N-bit digital-to-analog converter 1. The registers in the conventional digital-to-analog converter usually include unused bits. Figure 3A In the example, these unused bits are used as M enhancement bits 22, and the M enhancement bits 22 are consecutively appended to the N bits 21.

[0097] exist Figure 3BIn the embodiment, the output data register 4 includes N bits 21 and unused bits, while the M enhancement bits 22 are provided by a separate enhancement register 23. Figure 3A In the embodiment shown, Figure 3B In the illustrated embodiment, since the two registers can be operated independently of each other, optimized processing freedom is provided.

[0098] For example, in the peak current mode control of the switch mode power supply 10, Figure 3A The embodiment shown can be used to perform down-slope compensation, while Figure 3B The illustrated embodiment may be used to perform either down-slope compensation or up-slope compensation.

[0099] Figure 4 The relationship between the input and output of an N-bit digital-to-analog converter 1 is illustrated. The N-bit digital-to-analog converter 1 receives digital data 2 as input and converts it into an analog output voltage 3. Figure 4 It can be seen from the dotted line representing the digital data 2 and the solid line representing the output voltage 3 that the range of analog values ​​that can be represented by the digital data 2 is greater than the output voltage range of the N-bit digital-to-analog converter 1 .

[0100] To obtain Figure 4 The evaluation logic module 6 of the N-bit digital-to-analog converter 1 compares the digital data 2 stored in the output data register 4 and the M enhancement bits 5 with a threshold value, wherein the threshold value is adjustable and corresponds to the maximum output voltage or the middle voltage in the output voltage range of the N-bit digital-to-analog converter 1. If the digital data 2 currently considered is greater than the threshold value, the output of the N-bit digital-to-analog converter 1 is clamped at the output voltage corresponding to the threshold value; if the digital data 2 currently considered is less than or equal to the threshold value, the output of the N-bit digital-to-analog converter 1 corresponds to the digital data 2 currently considered.

[0101] In addition to clamping the digital data 2 greater than the threshold, the digital data 2 less than the threshold can also be clamped at an output voltage corresponding to the threshold. In addition, the evaluation logic module 6 of the N-bit digital-to-analog converter 1 can also use multiple thresholds.

[0102] Figure 5A , Figure 5B and Figure 5C The threshold values ​​used by the N-bit digital-to-analog converter 1 in the current mode control of the switch mode power supply 10 are illustrated. Figure 5A , a current sensing signal 16 obtained by a current sensor 20 is shown, wherein the current sensing signal has an offset 26, and the offset 26 is FIG. 5A to FIG. 5CIn the example, it is 1.5V. FIG. 5A to FIG. 5C In the illustrated embodiment, the current sensor 20 may, for example, map a current of 0 A to 1.5 V, a current of 10 A to 3 V, and a current of −10 A to 0 V.

[0103] Figure 5B FIG. 4 shows a case where the current sensor 20 is used in current mode control and no threshold is used. Figure 5C FIG. 2 shows a case where a current sensor 20 is used in current mode control and a threshold value is used. Figure 5B and Figure 5C In FIG. 1 , a current sensing signal 16 based on the current flowing through the inductor in the switch mode power supply 10 is shown, and a pulse width modulation signal 25 for controlling the switch in the switch mode power supply 10 to turn on or off is also shown.

[0104] like Figure 5B and Figure 5C As shown in FIG. 1 , when the current sensing signal 16 is equal to the output voltage 3 of the N-bit digital-to-analog converter, the switch of the switch-mode power supply 10 is turned off. After the switch is turned off, the current begins to decrease. Figure 5B In the illustrated embodiment, since the current sensor 20 does not use a threshold value, the current flowing through the switch mode power supply 10 cannot be fully established, thereby limiting the performance of the switch mode power supply 10 .

[0105] This problem can be solved by the N-bit digital-to-analog converter 1 proposed in this case. Figure 5C As shown, the evaluation logic module 6 of the N-bit digital-to-analog converter 1 is used to clamp the output voltage 3 to the value corresponding to the offset 26 when the received digital data 2 is less than the value corresponding to the offset 26 of the current sensor 20, so that the current flowing through the switch mode power supply 10 can be fully established. In addition, due to the use of the threshold value, the duty cycle determined by the pulse width modulation signal 25 may change during the operation of the switch mode power supply 10.

[0106] Fig. 6A and Figure 6B FIG. 1 is a schematic diagram of protecting a switch mode power supply 10 by using a threshold in an N-bit digital-to-analog converter 1. Fig. 6A As shown, when the input voltage of the switch mode power supply 10 changes rapidly, the current flowing through the switch mode power supply 10 will rise rapidly as can be seen from the current sensing signal 16. If no threshold is set, a large current 27 will be generated, and this large current 27 may cause the switch mode power supply 10 to be damaged.

[0107] like Figure 6B As shown, by the N-bit digital-to-analog converter 1 of the present invention, the digital data 2 greater than the threshold value will be clamped to the output voltage 3 within the output voltage range of the N-bit digital-to-analog converter 1. Figure 6B As shown, when the input voltage changes suddenly and causes the current to rise, the current sensing signal 16 corresponding to the current will reach the output voltage 3 of the N-bit digital-to-analog converter 1 earlier, thereby stopping the current from rising and causing the mixed-signal microcontroller 9 to turn off the switch of the switch mode power supply 10 earlier.

[0108] According to one aspect of the present invention, an N-bit digital-to-analog converter is provided, which has an output voltage range between a minimum output voltage and a maximum output voltage, wherein N is a positive integer, and the N-bit digital-to-analog converter is used to receive digital data as input and provide an output voltage as output according to the digital data. The N-bit digital-to-analog converter comprises:

[0109] At least one register, including an output data register and M enhanced bits, wherein the output data register has at least N bits, M is a positive integer, and the N-bit digital-to-analog converter is used to store the received digital data in the output data register and the M enhanced bits;

[0110] an evaluation logic module for providing at least one binary evaluation signal derived from the digital data stored in the output data register and the M enhancement bits, each binary evaluation signal comprising a first binary evaluation signal value or a second binary evaluation signal value; and

[0111] The converter is used for receiving the binary evaluation signal, wherein the converter can access the output data register and is used for providing an output signal according to the output data register and the received binary evaluation signal.

[0112] The N-bit digital-to-analog converter is used to map a digital input value to an analog output value, wherein the analog output value is within an output voltage range between a minimum output voltage and a maximum output voltage. For example, the output voltage range can be between ground and a reference voltage V REF between, or at a negative reference voltage -V REF and reference voltage V REF The N-bit digital-to-analog converter is used to map the N-bit encoded digital signal into the output voltage range (for example, by evenly distributing 2 N possible N-bit coded digital signals), where the output voltage range may be, for example, between 0V and The actual output voltage is provided by a converter of an N-bit digital-to-analog converter, wherein the converter may, for example, include an R-2R ladder network for mapping the digital signal into an analog value. In addition to the R-2R ladder network, the converter may also use different methods known in the prior art for mapping the digital signal into an analog output voltage.

[0113] The N-bit digital-to-analog converter includes at least one register, wherein the register includes an output data register having at least N bits and M enhancement bits. As another example of a possible register, the N-bit digital-to-analog converter may include a shift register. The N-bit digital-to-analog converter may include an input pin and receive serial input data through the input pin, and the serial input data may include digital data as input. In addition to the digital data, the serial input data may also include further information for controlling the operation of the N-bit digital-to-analog converter. The N-bit digital-to-analog converter may also include another input pin and receive a clock signal through it, wherein the clock signal may determine the time of the N-bit digital-to-analog converter. When receiving the serial input data, the N-bit digital-to-analog converter first stores the received serial input data in the shift register, wherein the N-bit digital-to-analog converter may, for example, move the received serial input data to the shift register at each rising edge of the clock signal. Furthermore, for example, by other trigger signals received by the N-bit digital-to-analog converter through other dedicated input pins, the data stored in the shift register may be stored in the output data register and the M enhancement bits. Of course, in other implementations, the received digital data may be moved to the output data register and the M enhanced bits in other feasible ways.

[0114] The at least one register may also include an enhancement register different from the output data register, wherein the enhancement register may include M enhancement bits, or the output data register may include M enhancement bits, i.e., the output data register includes at least N+M bits. Since the digital data in the enhancement register may change (e.g., increase or decrease) independently of the digital data in the output data register, providing an enhancement register that is different from and independent of the output data register may provide more freedom in data processing. However, in both scenarios, the output data register and the M enhancement bits provide space for storing binary data for computational processing by the evaluation logic module of the N-bit digital-to-analog converter. The output data register and the M enhancement bits allow computational processing to be performed on an internal representation with a larger range of values ​​than the range encoded by the N bits converted to the output voltage by the converter.

[0115] The output data register and the M enhancement bits can be arranged on the same side, and the converter can be arranged on the other side, so that the digital data stored in the output data register and the M enhancement bits will not be directly converted into an analog output voltage by the converter. On the contrary, at least one register of the N-bit digital-to-analog converter can, for example, include a converter register with N bits, wherein the converter can directly operate the converter register, and the binary data stored in the converter register can be used to turn on or off the switch of the R-2R ladder network of the converter. The binary data stored in the converter register depends on the digital data stored in the output data register and the binary evaluation signal provided by the evaluation logic module. In the case of setting this converter register, the converter can include a control logic module, wherein the control logic module is used to write binary data into the converter register according to the binary evaluation signal and the digital data stored in the output data register.

[0116] Alternatively, the converter can operate directly on the digital data stored in the output data register, i.e., without setting the converter register. In this case, the converter includes a control logic module, wherein the control logic module takes into account both the N-bit digital data stored in the output data register and the binary evaluation signal when controlling the switches of the R-2R ladder network of the converter.

[0117] Each binary evaluation signal theoretically corresponds to a binary decision, i.e., whether the digital data stored in the output data register and the M enhancement bits satisfy a specific attribute. For example, a possible binary decision is that the stored digital data is less than or greater than a threshold value. Each binary evaluation signal may have two possible binary evaluation signal values, one of which indicates that the stored digital data does not satisfy the attribute, and the other indicates that the stored digital data satisfies the attribute. The attribute may be memoryless, i.e., whether the digital data processed by the evaluation logic module satisfies the corresponding attribute may be independent of whether the previously stored digital data satisfies the corresponding attribute. In addition, the evaluation logic module may also adopt a time-dependent attribute, i.e., whether the digital data processed by the evaluation logic module satisfies the corresponding attribute may depend on whether the previously stored digital data satisfies the corresponding attribute. In order to be able to handle such a time-dependent attribute, the N-bit digital-to-analog converter may include an internal storage device, wherein the internal storage device is used to store the binary evaluation signal.

[0118] Advantageously, the proposed N-bit digital-to-analog converter can receive digital data as input, and the digital data may not be represented by N bits, wherein the N bits together with the output voltage range define the output resolution of the N-bit digital-to-analog converter. However, via the binary evaluation signal, information about the received digital data can be determined and possibly used to adjust the output voltage of the N-bit digital-to-analog converter.

[0119] In an N-bit digital-to-analog converter of an embodiment of the present invention, the minimum output voltage and the maximum output voltage depend on a reference voltage provided to the N-bit digital-to-analog converter.

[0120] In an N-bit DAC of one embodiment of the present invention, the number of enhancement bits is adjustable. Advantageously, the range of digital data received as input by the N-bit DAC is also adjustable.

[0121] In an N-bit digital-to-analog converter of one embodiment of the present case, each binary evaluation signal corresponds to a threshold value, and the evaluation logic module is used to provide a binary evaluation signal by comparing the digital data stored in the output data register and the M enhancement bits with the threshold value, and the evaluation logic module sets the binary evaluation signal to a first binary evaluation signal value or a second binary evaluation signal value according to the comparison result.

[0122] In an N-bit digital-to-analog converter of one embodiment of the present invention, the output data register includes M enhancement bits, and the M enhancement bits are consecutively appended after the N bits, so that the output data register includes a total of N+M bits for storing digital data. Therefore, the maximum value stored in the N+M bits is 2 N+M -1.

[0123] In an N-bit digital-to-analog converter of an embodiment of the present invention, the evaluation logic module is used to provide a first binary evaluation signal, the first binary evaluation signal corresponds to a first threshold value, and the first threshold value is adjustable or equal to 2 N The converter is used to store the digital data in the output data register and the M enhancement bits when the digital data is greater than the adjustable first threshold or 2 N -1, provides the value corresponding to the adjustable first threshold or 2 N The converter is also used to store the digital data in the output data register and the M enhancement bits less than or equal to the adjustable first threshold or 2 N When -1, the output voltage is provided according to the digital data.

[0124] In an N-bit digital-to-analog converter of an embodiment of the present invention, the evaluation logic module is used to provide a second binary evaluation signal, the second binary evaluation signal corresponds to a second threshold value, the second threshold value is adjustable and is less than the first threshold value. The converter is used to provide an output voltage corresponding to the second threshold value when the digital data stored in the output data register and the M enhancement bits is less than the adjustable second threshold value. The converter is also used to provide an output voltage corresponding to the digital data when the digital data stored in the output data register and the M enhancement bits is greater than or equal to the adjustable second threshold value.

[0125] In an N-bit digital-to-analog converter of an embodiment of the present invention, the register includes an enhancement register, and the enhancement register includes the aforementioned M enhancement bits.

[0126] According to another aspect of the present invention, there is provided a mixed signal microcontroller for current mode control of a switch mode power supply, comprising:

[0127] A compensation control logic module for providing a series of digital compensation control values ​​derived from a voltage sensing signal, wherein the voltage sensing signal corresponds to a power supply output voltage of the switch mode power supply;

[0128] A slope compensation logic module for providing a series of digital slope compensation values, wherein the series of digital slope compensation values ​​are suitable for a switch mode power supply;

[0129] Any of the aforementioned N-bit digital-to-analog converters, wherein the N-bit digital-to-analog converter is used to receive a series of digital compensation control values ​​and a series of digital slope compensation values ​​as inputs, and provide a voltage control signal as output;

[0130] a comparator for comparing the voltage control signal with a voltage value corresponding to a current sensing signal and providing a comparator voltage signal as an output, wherein the current sensing signal corresponds to a current flowing through the switch mode power supply; and

[0131] The drive control logic module is used to receive the comparator voltage signal as input and provide a drive signal for the switch of the switch mode power supply as output.

[0132] Current mode control is a well-known technique for controlling switch mode power supplies, which may be peak current mode control, valley current mode control or analog current mode control. In current mode control of switch mode power supplies, the occurrence of subharmonic oscillations is a known problem, which is manifested in alternating wide pulses and narrow pulses. To prevent the occurrence of subharmonic oscillations, the available prior art is slope compensation. Current mode control is generally implemented as analog current mode control or digital current mode control. The mixed signal microcontroller proposed in this case is designed for digital current mode control.

[0133] The mixed signal microcontroller is used to control the switching action of the switch in the switch mode power supply through its driver control logic module. To this end, the mixed signal microcontroller may include a pulse width modulation controller. For example, if the switch mode power supply is a buck converter, the ratio of the power supply output voltage of the buck converter to its input voltage ideally corresponds to the duty cycle of the switch operation of the buck converter. Assuming that the buck converter does not include a second switch for synchronous rectification, but only includes a diode, a single switch of the buck converter can be controlled by the mixed signal microcontroller. This switch is periodically turned on at the switching frequency so that current flows through the switch. Once the switch is turned on, the current flowing through the inductor of the buck converter begins to rise. In each switching cycle, the mixed signal microcontroller is used to determine the time point when the switch should be turned off, and when the switch is turned off, the current flowing through the inductor of the buck converter begins to decrease. More generally, for other types of switch mode power supplies, the mixed signal microcontroller can periodically turn on the switch of the switch mode power supply in each switching cycle, and then turn off the switch.

[0134] During steady-state operation of the switch-mode power supply, the slope compensation logic module can provide a digital slope compensation value in the form of a periodically repeated compensation ramp signal, wherein the slope compensation period of the compensation ramp signal should ideally be close to the switching period of the switch-mode power supply. Typically, the type of slope compensation used (parameters that may need to be set include but are not limited to the height of the compensation ramp signal, the number of steps in each slope compensation period, the rising slope or falling slope used, the duration of the slope compensation period, etc.) depends on the type of switch-mode power supply, the mode of operation of the switch-mode power supply, and the type of current mode control used. In addition, the specific architecture of the slope compensation logic module can be known from the prior art in the field and will not be repeated here.

[0135] For example, for a buck converter using analog peak current mode control, the slope of the analog compensation signal may be set based on the falling slope of the current flowing through the inductor of the buck converter, that is, the slope of the analog compensation signal may be proportional to the ratio of the power supply output voltage (i.e., the output voltage of the buck converter) and the inductance value of the inductor of the buck converter. Similarly, for a boost converter using analog peak current mode control, the slope of the analog compensation signal may be set to be proportional to the ratio of (i) the difference between the power supply output voltage (i.e., the output voltage of the boost converter) and the input voltage of the boost converter and (ii) the inductance value of the inductor of the boost converter. Similarly, for a buck-boost converter using analog peak current control, the slope of the analog compensation signal may be set to be proportional to the ratio of the power supply output voltage (i.e., the output voltage of the buck-boost converter) and the inductance value of the inductor of the buck-boost converter. In summary, for a buck converter, a boost converter, and a buck-boost converter, when an analog peak current mode control is adopted, the slope of the compensation signal can be set based on the falling slope of the current flowing through the inductor of the converter. In addition, when the buck converter, the boost converter, or the buck-boost converter is controlled, for example, with an analog valley current mode control, the slope of the compensation signal can be set based on the rising slope of the current flowing through the inductor of the converter.

[0136] For digital current mode control, the slope compensation logic module does not provide the aforementioned analog compensation signal, but instead provides digital slope compensation values ​​with the same effect, and these digital slope compensation values ​​are subtracted or added to the digital compensation control values. The digital compensation control values ​​can be provided by the compensation control logic module at a rate corresponding to the switching frequency of the switch mode power supply. In the case where the slope compensation period is less than or equal to the switching period, the sequence of steps in each slope compensation period may be provided at a higher frequency than the switching frequency, and the corresponding clock signal is also provided to the N-bit digital-to-analog converter.

[0137] For example, in the case where the switch-mode power supply is a buck converter and the mixed-signal microcontroller is configured to perform digital peak current mode control, the N-bit digital-to-analog converter of the mixed-signal microcontroller performs the following actions in each switching cycle. First, at the beginning of the switching cycle, one of the series of digital compensation control values ​​is provided to the N-bit digital-to-analog converter and stored in the output data register and the M enhancement bits. Then, before the next digital compensation control value is provided to the N-bit digital-to-analog converter, the stored digital compensation control value will be subtracted from each digital slope compensation value in sequence. Therefore, the stored digital compensation control value will gradually decrease.

[0138] The N-bit digital-to-analog converter provides a voltage control signal as an output.

[0139] Continuing with the example of the switch mode power supply being a buck converter and the mixed signal microcontroller using digital peak current mode control, the comparator of the mixed signal microcontroller is used to compare the current sensing signal with the voltage control signal. In this example, the current sensing signal corresponds to the peak value of the current flowing through the inductor of the buck converter. In order to obtain the current sensing signal, a resistor or a current transformer may be used, for example. The current sensing signal may be provided to the mixed signal microcontroller as an input. Furthermore, based on the comparison result (i.e., the comparator voltage signal), the drive control logic module of the mixed signal microcontroller may determine the drive signal for driving the switch of the buck converter.

[0140] Under typical operating conditions of a buck converter, boost converter, or buck-boost converter, for example, using analog peak current mode control, the current sensing signal may be limited to a range narrower than the possible value range of the analog slope compensation signal within one switching cycle. Therefore, the N-bit digital-to-analog converter of the mixed-signal microcontroller can be implemented as follows: the N bits of the N-bit digital-to-analog converter do not represent the possible value range of the analog compensation signal within one switching cycle, but represent the narrower range of the current sensing signal, and the N+M bits provided by the output data register and the M enhancement bits jointly represent the possible value range of the analog compensation signal within one switching cycle. Thereby, the N-bit digital-to-analog converter of the mixed-signal microcontroller proposed in the present case can improve the resolution within the narrower value range of the current sensing signal, wherein the narrower value range is related to the subsequent comparison of the voltage control signal and the current sensing signal; while retaining the ability to process the possible value range of the analog compensation signal within one switching cycle. If a conventional N-bit DAC is used instead of the proposed N-bit DAC, the resolution within the relevant range of current mode control will be lower because N bits will be used to represent the possible value range of the analog compensation signal within a switching cycle.

[0141] For example, for a buck converter using analog peak current mode control, the evaluation logic module of the N-bit digital-to-analog converter can provide a binary evaluation signal. If the digital data currently stored in the output data register and the M enhancement bits (corresponding to the gradually decreasing digital compensation control value) is greater than 2 N -1, the N-bit digital-to-analog converter can provide the maximum output voltage as the output voltage. If the digital data currently stored in the output data register and the M enhancement bits is less than or equal to 2 N -1, the converter of the N-bit digital-to-analog converter can provide a voltage within the output voltage range corresponding to the currently stored digital data.

[0142] The power supply output voltage of the switch mode power supply can be provided to a mixed signal microcontroller via a voltage divider, and the mixed signal microcontroller can include an analog-to-digital converter, wherein the analog-to-digital converter samples a portion of the power supply output voltage provided by the voltage divider, and then the sampled value can be provided to a digital filter, which in turn outputs a digital compensation control value.

[0143] By using a mixed signal microcontroller for current mode control of a switch mode power supply, it is advantageous to use a current sensor to sense the current in the switch mode power supply, wherein the current sensor has an output voltage offset. In addition, by using a mixed signal microcontroller for current mode control of the switch mode power supply, it is also advantageous to improve the protection of the switch mode power supply in the event of a rapid increase in current in the switch mode power supply.

[0144] In a mixed signal microcontroller of one embodiment of the present case, the mixed signal microcontroller further includes an analog-to-digital converter and / or a drive control logic module, wherein the analog-to-digital converter is used to receive a voltage sensing signal as an input and provide a digital voltage sensing signal to the compensation control logic module as an output; the drive control logic module includes a pulse width modulation controller.

[0145] In a mixed signal microcontroller of one embodiment of the present case, a series of digital slope compensation values ​​is a periodically repeated compensation ramp signal, and for each digital compensation control value, the mixed signal microcontroller is used to store the digital compensation control value in an output data register and M enhancement bits, and before storing subsequent digital compensation control values ​​in the output data register and M enhancement bits, the stored digital compensation control value is adjusted by adding or subtracting the digital slope compensation value in a period of the compensation ramp signal from the stored digital compensation control value.

[0146] In a mixed signal microcontroller according to an embodiment of the present invention, an evaluation logic module of an N-bit digital-to-analog converter is used to provide a binary evaluation signal after adjusting the stored digital compensation control value.

[0147] The binary evaluation signal may be provided after a series of digital compensation control values ​​have been adjusted, rather than after each adjustment of the stored digital compensation control value.

[0148] In a mixed signal microcontroller of an embodiment of the present case, the mixed signal microcontroller is suitable for peak current mode control, and the slope compensation logic module is used to provide a compensation ramp signal, the slope of the compensation ramp signal corresponds to the falling slope of the inductor current flowing through the inductor of the switch mode power supply.

[0149] In a mixed signal microcontroller of an embodiment of the present invention, the mixed signal microcontroller is suitable for valley current mode control, and the slope compensation logic module is used to provide a compensation ramp signal, and the slope of the compensation ramp signal corresponds to the rising slope of the inductor current flowing through the inductor of the switch mode power supply. The register of the N-bit digital-to-analog converter includes an enhancement register, and the enhancement register includes the aforementioned M enhancement bits.

[0150] Since the data in the enhancement register can be changed independently of the data in the output data register, the N-bit digital-to-analog converter including the independent enhancement register in the present case can improve the degree of freedom of data processing.

[0151] In a mixed signal microcontroller of an embodiment of the present invention, the mixed signal microcontroller is configured to be suitable for current mode control of a buck converter, current mode control of a boost converter, or current mode control of a buck-boost converter.

[0152] It should be noted that the above is only a preferred embodiment for illustrating the present invention, and the present invention is not limited to the embodiment described. The scope of the present invention is determined by the attached claims. Moreover, the present invention may be modified in various ways by those skilled in the art, but all of them are within the scope of the protection intended by the attached claims.

Claims

1. An N-bit digital-to-analog converter having an output voltage range between a minimum output voltage and a maximum output voltage, wherein N is a positive integer, the N-bit digital-to-analog converter is used to receive a digital data as an input and provide an output voltage as an output according to the digital data, the N-bit digital-to-analog converter comprising: At least one register, including an output data register and M enhanced bits, wherein the output data register has at least N bits, M is a positive integer, and the N-bit digital-to-analog converter is used to store the received digital data in the output data register and the M enhanced bits; an evaluation logic module for providing at least one binary evaluation signal derived from the digital data stored in the output data register and the M enhancement bits, each of the binary evaluation signals comprising a first binary evaluation signal value or a second binary evaluation signal value; and A converter is used for receiving the at least one binary evaluation signal, wherein the converter is adapted to access the output data register and provide the output signal according to the output data register and the received at least one binary evaluation signal.

2. The N-bit digital-to-analog converter of claim 1, wherein the minimum output voltage and the maximum output voltage depend on a reference voltage provided to the N-bit digital-to-analog converter.

3. The N-bit digital-to-analog converter of claim 1, wherein the number of enhancement bits is adjustable.

4. The N-bit digital-to-analog converter as claimed in claim 1 , wherein each of the binary evaluation signals corresponds to a threshold value, the evaluation logic module is used to provide the binary evaluation signal by comparing the digital data stored in the output data register and the M enhancement bits with the threshold value, and the evaluation logic module sets the binary evaluation signal to the first binary evaluation signal value or the second binary evaluation signal value according to the comparison result.

5. The N-bit digital-to-analog converter as claimed in claim 4, wherein the output data register comprises the M enhancement bits, and the M enhancement bits are consecutively appended after the N bits, so that the output data register comprises a total of N+M bits for storing the digital data.

6. The N-bit digital-to-analog converter of claim 4, wherein the evaluation logic module is used to provide a first binary evaluation signal, the first binary evaluation signal corresponds to a first threshold value, the first threshold value is adjustable or equal to 2 N -1; the converter is used to store the digital data in the output data register and the M enhancement bits when it is greater than the adjustable first threshold or 2 N -1, provides the first threshold value or 2 N -1; the converter is used when the digital data stored in the output data register and the M enhancement bits is less than or equal to the adjustable first threshold or 2 N When -1, the output voltage is provided according to the digital data.

7. An N-bit digital-to-analog converter as described in claim 6, wherein the evaluation logic module is used to provide a second binary evaluation signal, the second binary evaluation signal corresponds to a second threshold, the second threshold is adjustable and less than the first threshold; when the digital data stored in the output data register and the M enhancement bits is less than the adjustable second threshold, the converter is used to provide the output voltage corresponding to the second threshold; when the digital data stored in the output data register and the M enhancement bits is greater than or equal to the adjustable second threshold, the converter is used to provide the output voltage corresponding to the digital data. 8 . The N-bit digital-to-analog converter of claim 4 , wherein the at least one register comprises an enhancement register, the enhancement register comprising the M enhancement bits.

9. A mixed signal microcontroller for current mode control of a switch mode power supply, comprising: a compensation control logic module for providing a series of digital compensation control values ​​derived from a voltage sensing signal, wherein the voltage sensing signal corresponds to a power output voltage of the switch mode power supply; a slope compensation logic module for providing a series of digital slope compensation values, wherein the series of digital slope compensation values ​​are applicable to the switch mode power supply; The N-bit digital-to-analog converter according to any one of claims 1 to 8, wherein the N-bit digital-to-analog converter is used to receive the series of digital compensation control values ​​and the series of digital slope compensation values ​​as inputs, and provide a voltage control signal as output; a comparator for comparing the voltage control signal with a voltage value corresponding to a current sensing signal and providing a comparator voltage signal as an output, wherein the current sensing signal corresponds to a current flowing through the switch mode power supply; as well as A drive control logic module is used to receive the comparator voltage signal as an input and provide a drive signal for the switch of the switch mode power supply as an output.

10. The mixed signal microcontroller as claimed in claim 9, further comprising an analog-to-digital converter, wherein the analog-to-digital converter is used to receive the voltage sensing signal as an input and provide a digital voltage sensing signal to the compensation control logic module as an output.

11. The mixed signal microcontroller as claimed in claim 9 or 10, wherein the drive control logic module comprises a pulse width modulation controller.

12. A mixed signal microcontroller as claimed in claim 9 or 10, wherein the series of digital slope compensation values ​​is a periodically repeated compensation ramp signal, and for each of the digital compensation control values, the mixed signal microcontroller is used to store the digital compensation control value in the output data register and the M enhancement bits, and before storing the subsequent digital compensation control value in the output data register and the M enhancement bits, adjust the stored digital compensation control value by adding or subtracting the digital slope compensation value in one cycle of the compensation ramp signal from the stored digital compensation control value. 13 . The mixed signal microcontroller as claimed in claim 12 , wherein the evaluation logic module of the N-bit digital-to-analog converter is configured to provide a binary evaluation signal after adjusting the stored digital compensation control value.

14. The mixed signal microcontroller as claimed in claim 12, wherein the mixed signal microcontroller is suitable for peak current mode control, and the slope compensation logic module is used to provide the compensation ramp signal, and the slope of the compensation ramp signal corresponds to the falling slope of the inductor current flowing through the inductor of the switch mode power supply.

15. The mixed signal microcontroller as claimed in claim 12, wherein the mixed signal microcontroller is suitable for valley current mode control, the slope compensation logic module is used to provide the compensation ramp signal, the slope of the compensation ramp signal corresponds to the rising slope of the inductor current flowing through the inductor of the switch mode power supply, and the N-bit digital-to-analog converter is the N-bit digital-to-analog converter as claimed in claim 8.

16. The mixed signal microcontroller of claim 9, adapted for current mode control of a buck converter, current mode control of a boost converter, or current mode control of a buck-boost converter.

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