Multiphase DC / DC converter

Abstract

A multiphase DC / DC converter (10) that comprises a plurality of DC / DC converters (20) that perform voltage conversion by control of a high-side FET (21) and a low-side FET (22) comprises respective thermistors (90) that measure the temperatures of the high-side FETs (21) of the DC / DC converters (20) and an output control unit (41) that alters control of the DC / DC converter (20) that includes the high-side FET (21) that has the highest temperature of the temperatures of the high-side FETs (21) measured by the thermistors (90) so as to reduce the temperature of the high-side FET (21).

Description

Multi-phase DC-DC converter Cross-reference to related applications

[0001] This application is based on Japanese Patent Application No. 2025-018534 filed in Japan on February 6, 2025, and the content of the base application is incorporated herein by reference in its entirety.

[0002] Regarding a multi-phase DC-DC converter, particularly regarding its temperature control.

[0003] A multi-phase DC-DC converter that outputs a large current is known by connecting a plurality of DC-DC converters in parallel and shifting the phases of the currents output by each DC-DC converter. Patent Document 1 discloses a technique for balancing the temperatures of a plurality of DC-DC converters included in a multi-phase DC-DC converter. The description of the prior art document is incorporated herein by reference as an explanation of the technical elements in this specification.

[0004] U.S. Patent No. 8,587,272

[0005] In Patent Document 1, the temperature of each phase is measured, and an average temperature obtained by averaging the measured temperatures of each phase is calculated. Then, based on the temperature difference between this average temperature and the temperature of each phase, the duty ratio of each phase is adjusted. Therefore, it is necessary to calculate the average temperature, and a complicated calculation of calculating the duty ratio from the average temperature is required.

[0006] The present disclosure has been made based on this situation, and an object thereof is to provide a multi-phase DC-DC converter that can reduce the temperature difference between a plurality of DC-DC converters with a simple configuration.

[0007] The above object is achieved by the combination of features described in the independent claims, and the dependent claims define further advantageous specific examples. The reference numerals in parentheses described in the claims indicate the correspondence with the specific embodiments described in the embodiments described later as one aspect, and do not limit the disclosed technical scope.

[0008] One disclosure for achieving the above objective is a multiphase DC-DC converter comprising a plurality of DC-DC converters that perform voltage conversion by switch control, the multiphase DC-DC converter comprising: a temperature measuring unit that measures the temperature of a heat-generating component in each DC-DC converter; and a switch control unit that changes the control of the switch of the DC-DC converter having the hottest heat-generating component among those measured by the temperature measuring unit, so as to lower the temperature of the heat-generating component.

[0009] This multi-phase DC-DC converter modifies the switch control of the DC-DC converter containing the hottest heat-generating component to reduce the temperature of that component. This lowers the temperature of the hottest component, resulting in a smaller temperature difference between the multiple DC-DC converters. Furthermore, it allows for a simpler configuration compared to calculating the average temperature and then deriving the duty cycle from that average temperature.

[0010] Another disclosure for achieving the above objective is a multiphase DC-DC converter comprising a plurality of DC-DC converters that perform voltage conversion by switch control, the multiphase DC-DC converter comprising: a temperature measuring unit having a characteristic value that changes with temperature and arranged so that the characteristic value changes in accordance with the temperature of the heat-generating components of each DC-DC converter; and a switch control unit that changes the control of the switches of the plurality of DC-DC converters in a direction in which the characteristic values ​​of the temperature measuring units become equal.

[0011] This reduces the temperature difference between multiple DC-DC converters. Furthermore, it allows for a simpler configuration compared to calculating the average temperature and then deriving the duty cycle from that average temperature.

[0012] A diagram illustrating the configuration of a multi-phase DC-DC converter according to the first embodiment. A diagram illustrating the adjustment control performed by the output control unit of the first embodiment. A diagram illustrating the configuration of a multi-phase DC-DC converter according to the second embodiment. A diagram illustrating the adjustment control performed by the output control unit of the second embodiment.

[0013] <First Embodiment> The embodiments will now be described based on the drawings. Figure 1 is a configuration diagram of the multiphase DC-DC converter 10 of the first embodiment. The multiphase DC-DC converter 10 supplies power to the load 5. The load 5 is an electrical device that operates using power supplied from the multiphase DC-DC converter 10. An example of the load 5 is a computer mounted in a vehicle. However, the load 5 may be other electrical devices mounted in a vehicle, or it may be an electrical device used outside of a vehicle, such as a supercomputer or server.

[0014] The multiphase DC-DC converter 10 comprises four DC-DC converters 20A, 20B, 20C, and 20D, an output voltage detection unit 30, a control IC (Integrated Circuit) 40 for controlling the four DC-DC converters 20A, 20B, 20C, and 20D, a shunt resistor 60, and a capacitor 70. The four DC-DC converters 20A, 20B, 20C, and 20D have the same configuration. When the four DC-DC converters 20A, 20B, 20C, and 20D are not distinguished, they are referred to as DC-DC converter 20. The number of DC-DC converters 20 is not limited to four; there may be more than four.

[0015] The DC-DC converter 20 is a buck-type DC-DC converter that steps down the input voltage Vin, i.e., converts it to a lower voltage. The input voltage Vin is, for example, 48V, and the output voltage is, for example, 12V. The four DC-DC converters 20 are connected in parallel with each other. The DC-DC converter 20 includes a high-side FET (Field Effect Transistor) 21 and a low-side FET 22 that function as switches. In this embodiment, the high-side FET 21 and low-side FET 22 are N-channel type MOS (Metal-Oxide-Semiconductor) FETs.

[0016] The high-side FET 21 has its drain connected to the input voltage Vin, its source connected to the drain of the low-side FET 22, and its gate connected to the output control unit 41. The low-side FET 22 has its drain connected to the drain of the high-side FET 21, its source grounded, and its gate connected to the output control unit 41. A body diode 23 is formed on the high-side FET 21, and a body diode 24 is formed on the low-side FET 22. In Figure 1, for the sake of simplicity, only the high-side FET 21 and low-side FET 22 of the DC-DC converter 20A, as well as the body diodes 23 and 24, are shown with their corresponding numerals.

[0017] The DC-DC converter 20 includes a coil 25 in addition to the high-side FET 21 and the low-side FET 22. One end of the coil 25 is connected to the source of the high-side FET 21 and the drain of the low-side FET 22, and the other end is connected to the output line 80 via a shunt resistor 60.

[0018] The output voltage detection unit 30 comprises a first resistor 31 and a second resistor 32. The first resistor 31 and the second resistor 32 are connected in series. One end of the first resistor 31 is connected to the output line 80, and the other end is connected to one end of the second resistor 32. The other end of the second resistor 32 is grounded. The output voltage detection unit 30 inputs the voltage obtained by dividing the voltage of the output line 80, i.e., the output voltage, by the first resistor 31 and the second resistor 32 to the operational amplifier 42 of the control IC 40.

[0019] A shunt resistor 60 is provided for each DC-DC converter 20 to detect the current output by each DC-DC converter 20. The voltage across the shunt resistor 60 is input to the control IC 40. One end of the capacitor 70 is connected to the output line 80, and the other end is grounded.

[0020] The multiphase DC-DC converter 10 further includes a thermistor 90. The thermistor 90 is an element whose electrical resistance changes with temperature. In the thermistor 90, electrical resistance is a characteristic value that changes with temperature. The thermistor 90 may be either an NTC thermistor or a PTC thermistor. Four thermistors 90A, 90B, 90C, and 90D are provided, corresponding to the high-side FETs 21 that each of the four DC-DC converters 20 has. The four thermistors 90 form a temperature measuring unit that measures the temperature of the high-side FETs 21, which are one of the heat-generating components in the DC-DC converter 20.

[0021] When the four thermistors 90A, 90B, 90C, and 90D are not distinguished, they are referred to simply as thermistor 90. Each thermistor 90 is a temperature sensing element and is located near the high-side FET 21, which is the object whose temperature is to be measured. The four thermistors 90A, 90B, 90C, and 90D are connected in series. One end of thermistor 90A is connected to the constant voltage source Vreg. One end of thermistor 90D is grounded.

[0022] The control IC 40 is a single IC and includes either a processor or a hardware circuit, or both, as hardware elements. The hardware elements of the control IC 40 function as an output control unit 41. The control IC 40 also includes the aforementioned operational amplifier 42 for output voltage detection. In addition, the control IC 40 includes four operational amplifiers 43 for temperature measurement. Each operational amplifier 43 amplifies the voltage across the thermistor 90 and inputs it to the output control unit 41.

[0023] The operational amplifier 42 for output voltage detection inputs a signal indicating the voltage difference between the voltage detected by the output voltage detection unit 30 and a reference voltage to the output control unit 41. This operational amplifier 42 is sometimes called an error amplifier.

[0024] The output control unit 41 reduces current ripple while increasing the current flowing through the output line 80 by shifting the phase of the currents output by the four DC-DC converters 20 relative to each other. The output control unit 41 is a switch control unit that inputs PWM signals to the high-side FET 21 and low-side FET 22 of each DC-DC converter 20 to control the on / off state of these high-side FET 21 and low-side FET 22.

[0025] In PWM (Pulse Width Modulation) control, the duty cycle is determined based on the signal input from the operational amplifier 42 and the current output of each DC-DC converter 20. The current output of each DC-DC converter 20 is determined from the voltage across each shunt resistor 60. The duty cycle is determined such that the voltage supplied to the load 5 falls within a predetermined voltage range and that the current output by each phase, i.e., each DC-DC converter 20, is equal.

[0026] In addition, in the first embodiment, the output control unit 41 adjusts the duty cycle determined as described above based on the temperature detected by the thermistor 90, as will be explained next. Next, this adjustment control performed by the output control unit 41 will be explained with reference to Figure 2.

[0027] The process shown in Figure 2 begins when the multiphase DC-DC converter 10 is started. In S1, it is determined whether the output voltage is stable or not. If the result of the determination in S1 is NO, the determination in S1 is repeated. If the result of the determination in S1 is YES, the process proceeds to S2. In S2, it is determined whether there is an abnormality in the voltage across each thermistor 90. If the difference between the voltage across one thermistor 90 and the voltage across another thermistor 90 is excessive, the result of the determination in S2 is YES. Also, if the voltage across a thermistor 90 is excessive or too low, the result of the determination in S2 is YES. If the result of the determination in S2 is YES, the determination in S2 is repeated. If the result of the determination in S2 is NO, the process proceeds to S3.

[0028] In S3, the operation of load 5 is started. In S4, the thermistor 90 with the highest temperature is identified. Thermistor 90 measures the temperature of the high-side FET 21. Therefore, S4 identifies the high-side FET 21 with the highest temperature.

[0029] In S5, the duty cycle of the phase containing thermistor 90 identified in S4 is changed to a value lower by a predetermined value (for example, 1%). In S6, it is determined whether there is an abnormality in the difference in duty cycles between each phase. This determines whether there is an abnormality in the difference in duty cycles between phases, which are the control values. Note that the difference in duty cycles between phases may be judged by the ratio rather than the difference.

[0030] The purpose of the S6 decision is to determine whether the duty cycle has been reduced too much due to a malfunction in thermistor 90. Based on this purpose, if the difference between the maximum duty cycle and the minimum duty cycle in each phase is greater than the pre-set abnormality judgment value, an abnormality is detected, and the result of the S6 decision will be YES. If the result of the S6 decision is YES, the process proceeds to S7, where a power supply abnormality is determined and the process terminates.

[0031] If the result of S6 is NO, proceed to S8. In S8, determine if there is an abnormality in the output voltage. If there is an abnormality in the output voltage, the result of S8 will be YES. If the result of S8 is YES, proceed to S7, determine that there is a power supply abnormality, and terminate the process. On the other hand, if the result of S8 is NO, return to S4 and continue control.

[0032] In the first embodiment described above, the duty cycle of the DC-DC converter 20 equipped with the hottest high-side FET 21 is reduced (S4, S5). This lowers the temperature of the hottest high-side FET 21. As a result, the temperature difference between the multiple DC-DC converters 20 is reduced. This allows for a simpler configuration compared to the case where the average temperature is calculated and the duty cycle is calculated from that average temperature.

[0033] Furthermore, the four thermistors 90, each used to measure the temperature of the high-side FET 21 in each phase, are connected in series. This configuration avoids the influence of variations in the resistance values ​​of the fixed resistors, compared to a configuration where a fixed resistor is connected in series with each individual thermistor 90 to measure its voltage. Therefore, the temperatures of the four high-side FETs 21 can be compared with high accuracy.

[0034] Furthermore, the output control unit 41 determines whether there is an abnormality in the difference in duty cycles of each phase (S6). This allows it to determine whether the duty cycle has been reduced too much due to a malfunction in the thermistor 90.

[0035] <Second Embodiment> Next, a second embodiment will be described. In this second embodiment and subsequent descriptions, elements having the same reference numerals as those used up to that point are the same as the elements with the same reference numerals in the previous embodiments, unless otherwise specified. Also, when only a part of the configuration is described, the previously described embodiments can be applied to the other parts of the configuration.

[0036] Figure 3 is a configuration diagram of the multiphase DC-DC converter 100 of the second embodiment. The multiphase DC-DC converter 100 is a four-phase DC-DC converter, similar to the multiphase DC-DC converter 10 of the first embodiment.

[0037] The multiphase DC-DC converter 100 comprises four DC-DC converters 120A, 120B, 120C, and 120D, an output voltage detection unit 30, a capacitor 70, an output line 80, and a control IC 140. The four DC-DC converters 120A, 120B, 120C, and 120D have the same configuration. The four DC-DC converters 120A, 120B, 120C, and 120D are connected in parallel. When the four DC-DC converters 120A, 120B, 120C, and 120D are not distinguished, they are referred to as DC-DC converter 120. Note that there may be more than four DC-DC converters 120, and it does not have to be four.

[0038] The DC-DC converter 120 is a buck-type DC-DC converter, similar to the DC-DC converter 20 of the first embodiment. The DC-DC converter 120 includes a high-side FET 121 and a low-side FET 122 that function as switches, and a coil 25. The high-side FET 121 and low-side FET 122 are n-channel MOSFETs and have the same connection relationships as the high-side FET 21 and low-side FET 22 of the first embodiment. That is, the drain of the high-side FET 121 is connected to the input voltage Vin, the source is connected to the drain of the low-side FET 122, and the gate is connected to the output control unit 141. The drain of the low-side FET 122 is connected to the drain of the high-side FET 121, the source is grounded, and the gate is connected to the output control unit 141. A body diode 123 is formed on the high-side FET 121, and a body diode 124 is formed on the low-side FET 122. In the second embodiment, the high-side FET 121 and low-side FET 122 are provided by a control IC 140.

[0039] The control IC 140 includes a high-side FET 121, a low-side FET 122, an operational amplifier 42, an output control unit 141, a constant current source 142, and four diodes 143A, 143B, 143C, and 143D. Although not shown in the figure, the control IC 140 also includes a current mirror circuit for detecting the current of the high-side FET 121. When the four diodes 143A, 143B, 143C, and 143D are not distinguished, they are referred to as diode 143.

[0040] Diode 143 is a semiconductor temperature sensor, and its bandgap voltage changes with temperature, so its forward voltage changes according to temperature. The forward voltage is a characteristic value that changes with temperature. The four diodes 143 form a temperature measuring section for measuring the temperature of the high-side FET 121. There are the same number of diodes 143 as there are high-side FETs 121, and each diode 143 is a temperature sensing element and is located near the high-side FET 121.

[0041] Diodes 143A, 143B, 143C, and 143D are connected in series. The anode of diode 143A is connected to constant current source 142. The cathode of diode 143D is grounded. The voltage between the constant current source 142 and the anode of diode 143A, the voltage between the cathode of diode 143A and the anode of diode 143B, and the voltage between the cathode of diode 143B and diode 143C are input to the ADC terminal of output control unit 141.

[0042] Output control unit 141 includes, as hardware elements, one or both of a processor and a hardware circuit. Output control unit 141 reduces current ripple while making the current flowing through output line 80 a large current by mutually shifting the phases of the currents output by the four DC-DC converters 120. Output control unit 141 is a switch control unit that inputs PWM signals to high-side FET 121 and low-side FET 122 of each DC-DC converter 120 to control the on / off of those high-side FET 121 and low-side FET 122.

[0043] The duty ratio in PWM control is determined based on the signal input from operational amplifier 42 and the current values output by each DC-DC converter 120. Note that the current values output by each DC-DC converter 120 are detected by a current mirror circuit. The duty ratio is determined such that the voltage supplied to load 5 falls within a preset constant voltage range and the currents output by each phase, that is, each DC-DC converter 120, become equal.

[0044] In addition, in the second embodiment, output control unit 141 includes an analog-to-digital converter, and based on the voltage input to the ADC terminal, converts the temperature detected by each diode 143 into a digital signal and acquires it. Then, output control unit 141 adjusts the duty ratio determined as described above based on the temperature detected by diode 143 as will be described next. Next, this adjustment control executed by output control unit 141 will be described using FIG. 4.

[0045] In S11, it is determined whether the output voltage is stable or not. If the result of the determination in S11 is NO, the determination in S11 is repeated. If the result of the determination in S11 is YES, the process proceeds to S12. In S12, it is determined whether there is an abnormality in the forward voltage of diode 143. If the difference between the forward voltage of one diode 143 and the forward voltage of another diode 143 is excessive, the result of the determination in S12 is YES. Also, if the forward voltage of diode 143 is excessive, or if its forward voltage is insufficient, the result of the determination in S12 is YES. If the result of the determination in S12 is YES, the determination in S12 is repeated. If the result of the determination in S12 is NO, the process proceeds to S13.

[0046] In S13, the operation of load 5 is started. In S14, all forward voltages are measured. In the following S15, it is determined whether the forward voltages of all phases are approximately the same. To make the determination in S15, the difference between the maximum and minimum forward voltages of all phases may be calculated and this difference may be compared with a pre-set threshold. If the difference is smaller than the threshold, it is determined that the forward voltages of all phases are approximately the same. Alternatively, to make the determination in S15, the ratio between the maximum and minimum forward voltages of all phases may be calculated and this ratio may be compared with a pre-set threshold. If the ratio is smaller than the threshold, it is determined that the forward voltages of all phases are approximately the same. If the result of the determination in S15 is YES, the process returns to S14. On the other hand, if the result of the determination in S15 is NO, the process proceeds to S16.

[0047] In S16, the duty ratio of each phase is adjusted in the direction in which the forward voltages measured in the immediately preceding S14 become equal to each other. When the determination is made using the difference in the forward voltages in S15, in S16, the duty ratio after the change of each phase is determined in the direction in which the difference disappears. Also, when the determination is made using the ratio of the forward voltages in S15, in S16, the duty ratio after the change of each phase is determined in the direction in which the ratio approaches 1. The forward voltage is correlated with the temperature, and the higher the temperature, the lower the forward voltage. Therefore, for example, the duty ratio of the DC-DC converter 120 including the high-side FET 121 corresponding to the diode 143 with the lowest forward voltage, that is, the high-side FET 121 with the highest temperature, is decreased by a constant value (for example, 2%). In addition, the duty ratio of the DC-DC converter 120 including the high-side FET 121 corresponding to the diode 143 with the highest forward voltage may be increased by a constant value.

[0048] In S17, it is determined whether there is an abnormality in the difference in the duty ratio of each phase. The reason for making this determination in S17 is the same as that in S6. That is, it is to determine whether the duty ratio has been adjusted too much due to an abnormality in the diode 143. Note that the difference in the duty ratio between phases may be determined by a ratio instead of a difference. If the difference between the maximum duty ratio and the minimum duty ratio among each phase is larger than the abnormality determination value set in advance based on the above purpose, an abnormality occurs, that is, the determination result of S17 becomes YES. If the determination result of S17 is YES, the process proceeds to S18, and it is determined that there is a power supply abnormality and the process ends.

[0049] If the determination result of S17 is NO, the process proceeds to S19. In S19, the high-side FET 121 and the low-side FET 122 of each phase are switched with the duty ratio calculated in S16.

[0050] S20 is the same as S8, and it is determined whether there is an abnormality in the output voltage. If the determination result of S20 is YES, the process also proceeds to S18, and it is determined that there is a power supply abnormality and the process ends. On the other hand, if the determination result of S20 is NO, the process returns to S14 and the control continues.

[0051] In the second embodiment described above, a diode 143 is placed near the high-side FET 121 of each DC-DC converter 120 in order to measure its temperature. The output control unit 141 adjusts the duty cycle of each phase so that the forward voltages of the diodes 143 are equal (S14 to S19). This reduces the temperature difference between the multiple DC-DC converters 120. Also, in the second embodiment, the absolute temperature is not measured, so the configuration is simpler compared to the case where the absolute temperature is measured, the average temperature is calculated, and the duty cycle is calculated from that average temperature.

[0052] Furthermore, since the four diodes 143, each used to measure the temperature of the high-side FET 121 in each phase, are connected in series, the same current flows through all four diodes 143. In this configuration, if the four diodes 143 reach the same temperature, they will have the same forward voltage. On the other hand, if the four diodes 143 are not connected in series, the currents flowing through them may differ. Since the forward voltage is affected by the current, if the four diodes 143 are not connected in series, even if the forward voltage is the same, the four diodes 143 may not be at the same temperature. However, in the second embodiment, if the four diodes 143 reach the same temperature, they will have the same forward voltage. As a result, the difference in forward voltage measured in S14 accurately reflects the difference in temperature of each high-side FET 121.

[0053] Furthermore, the output control unit 141 determines whether there is an abnormality in the difference in duty cycles of each phase (S16). This allows it to determine whether the duty cycle is being over-adjusted due to a malfunction in the diode 143.

[0054] Although embodiments have been described above, the disclosed technology is not limited to the embodiments described above. The following modifications are also included within the scope of disclosure, and further modifications can be made in various ways without departing from the gist of the invention.

[0055] <Modification 1> The DC-DC converters 20 and 120 were buck-type and step-down type. However, the DC-DC converters may also be charge-pump type or H-bridge type. Furthermore, the DC-DC converters may also be boost-type or step-up / step-down type. In addition, the low-side FETs 22 and 122 of the DC-DC converters 20 and 120 may be replaced with diodes.

[0056] <Modification 2> In the embodiment, the temperature of the high-side FET 121 was measured as the heat-generating component. However, the temperature of the coil 25 may also be measured as the heat-generating component. Alternatively, the temperatures of both the high-side FET 121 and the coil 25 may be measured as the heat-generating components.

[0057] <Modification 3> In the embodiment, a thermistor 90 and a diode 143 were shown as the temperature measuring unit. However, the temperature measuring unit is not limited to those shown in the embodiment. Thermistor 90 is an example of a temperature measuring unit whose resistance value changes with temperature. Various materials can be used as the temperature measuring unit whose resistance value changes with temperature, such as TCR guaranteed resistance paste, metals such as platinum and copper, and alloys such as nickel-chromium alloy.

[0058] Diode 143 is an example of a temperature measurement unit that utilizes a bandgap. A bipolar transistor or a silicon MOSFET may be used as the temperature measurement unit that utilizes a bandgap. A bipolar transistor has a characteristic value in its base-emitter voltage that is temperature-dependent. A silicon MOSFET has a characteristic value in its on-resistance that is temperature-dependent. Furthermore, the temperature measurement unit is not limited to measuring the temperature of one heat-generating component with one temperature detection element, such as a thermistor 90 or diode 143. The temperature measurement unit may measure the temperature of one heat-generating component with a single circuit configuration. Of course, a diode 143 may be used in the first embodiment, or a thermistor 90 may be used in the second embodiment.

[0059] <Modification 4> In the first embodiment, the constant voltage source Vreg connected to one end of the four series-connected thermistors 90 may be replaced with a constant current source. Also, in the second embodiment, the constant current source connected to one end of the four series-connected diodes 143 may be replaced with a constant voltage source Vreg. In addition, a limiting resistor for limiting the current flowing through the diodes 143 may be connected in series with the four diodes 143 along with the constant voltage source Vreg.

[0060] <Modification 5> In the embodiment, the DC-DC converters 20 and 120 were controlled by PWM control. However, the DC-DC converters 20 and 120 may also be controlled by PFM (Pulse Frequency Modulation) control. In the case of PFM control, switching loss increases in proportion to frequency. On the other hand, loss due to on-resistance increases as the frequency decreases. Therefore, in the case of PFM control, the relationship between frequency and loss, which is a temperature change factor, becomes a curve with an inflection point. Thus, in the case of PFM control, the relationship between frequency and loss is set in advance. When applying PFM control, in S5 or S17, the frequency, which is the control value, is changed in the direction of decreasing temperature based on the above relationship for the phase with the highest temperature.

[0061] <Modification 6> In the embodiment, the multi-phase DC-DC converters 10 and 100 controlled all DC-DC converters 20 and 120 with a single control IC 40 and 140. However, it is also possible to have multiple control ICs, each of which controls one or more DC-DC converters to shift the phases of each DC-DC converter relative to each other. In other words, a multi-phase DC-DC converter may be configured by having multiple DC-DC converters with control ICs and connecting these multiple DC-DC converters with control ICs in parallel.

[0062] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, where they refer to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical ideas.

[0063] (Technical Concept 1) A multiphase DC-DC converter comprising a plurality of DC-DC converters (20) that perform voltage conversion by controlling switches (21, 22), the multiphase DC-DC converter comprising: a temperature measuring unit (90) that measures the temperature of a heat-generating component in each of the DC-DC converters; and a switch control unit (41) that changes the control of the switch of the DC-DC converter having the heat-generating component with the highest temperature measured by the temperature measuring unit so as to lower the temperature of the heat-generating component.

[0064] (Technical Concept 2) A multiphase DC-DC converter comprising a plurality of DC-DC converters that perform voltage conversion by controlling switches (121, 122), the multiphase DC-DC converter comprising: a temperature measuring unit (143) having a characteristic value that changes according to temperature, and arranged so that the characteristic value changes in accordance with the temperature of the heat-generating components of each DC-DC converter; and a switch control unit (141) that changes the control of the switches of the plurality of DC-DC converters in the direction in which the characteristic values ​​of the temperature measuring unit become equal.

[0065] (Technical Concept 3) The multiphase DC-DC converter according to Technical Concept 2, wherein the switch control unit determines the control values ​​of the switches of the plurality of DC-DC converters in a direction that makes the characteristic values ​​of the temperature measuring unit equal, based on the difference in the characteristic values.

[0066] (Technical Concept 4) The multiphase DC-DC converter according to Technical Concept 2, wherein the switch control unit determines the control values ​​of the switches of the plurality of DC-DC converters in a direction in which the characteristic values ​​of the temperature measuring unit become equal, based on the ratio of the characteristic values.

[0067] (Technical Concept 5) The multiphase DC-DC converter according to any one of Technical Concepts 1 to 4, wherein the temperature measuring unit comprises a plurality of temperature detection elements arranged near the heat-generating components of each of the plurality of DC-DC converters.

[0068] (Technical Concept 6) A multiphase DC-DC converter as described in Technical Concept 5, wherein the multiple temperature sensing elements are connected in series.

[0069] (Technical idea 7) A multiphase DC-DC converter according to technical idea 5 or 6, wherein the plurality of temperature sensing elements are elements whose electrical resistance changes with temperature.

[0070] (Technical idea 8) A multiphase DC-DC converter according to technical idea 5 or 6, wherein the plurality of temperature sensing elements are elements whose band gap size changes with temperature.

[0071] (Technical Concept 9) The multiphase DC-DC converter according to any one of Technical Concepts 1 to 8, wherein the heat-generating component includes a MOSFET.

[0072] (Technical Concept 10) A multiphase DC-DC converter according to any one of Technical Concepts 1 to 9, wherein the heat-generating component includes a coil.

[0073] (Technical Concept 11) The multiphase DC-DC converter according to any one of Technical Concepts 1 to 10, wherein the switch control unit determines whether the temperature measurement by the temperature measuring unit is abnormal based on the difference between the control value for controlling the switch of one DC-DC converter and the control value for controlling the switch of the other DC-DC converter.

Claims

1. A multiphase DC-DC converter comprising a plurality of DC-DC converters (20) that perform voltage conversion by controlling switches (21, 22), the multiphase DC-DC converter comprising: a temperature measuring unit (90) that measures the temperature of a heat-generating component in each of the DC-DC converters; and a switch control unit (41) that changes the control of the switch in the DC-DC converter having the heat-generating component with the highest temperature measured by the temperature measuring unit, so as to lower the temperature of the heat-generating component.

2. A multiphase DC-DC converter comprising a plurality of DC-DC converters that perform voltage conversion by controlling switches (121, 122), the multiphase DC-DC converter comprising: a temperature measuring unit (143) having a characteristic value that changes according to temperature, and arranged so that the characteristic value changes in accordance with the temperature of the heat-generating components of each DC-DC converter; and a switch control unit (141) that changes the control of the switches of the plurality of DC-DC converters in a direction in which the characteristic values ​​of the temperature measuring unit become equal.

3. The multiphase DC-DC converter according to claim 2, wherein the switch control unit determines the control values ​​of the switches of the plurality of DC-DC converters in a direction that makes the characteristic values ​​of the temperature measuring unit equal, based on the difference in the characteristic values.

4. The multiphase DC-DC converter according to claim 2, wherein the switch control unit determines the control values ​​of the switches of the plurality of DC-DC converters in a direction that makes the characteristic values ​​of the temperature measuring unit equal, based on the ratio of the characteristic values.

5. The multiphase DC-DC converter according to claim 1 or 2, wherein the temperature measuring unit comprises a plurality of temperature detection elements arranged near the heat-generating components of each of the plurality of DC-DC converters.

6. The multiphase DC-DC converter according to claim 5, wherein the plurality of temperature sensing elements are connected in series.

7. The multiphase DC-DC converter according to claim 5, wherein the plurality of temperature sensing elements are elements whose electrical resistance changes with temperature.

8. The multiphase DC-DC converter according to claim 5, wherein the plurality of temperature sensing elements are elements whose band gap size changes with temperature.

9. The multiphase DC-DC converter according to claim 1 or 2, wherein the heat-generating component includes a MOSFET.

10. The multiphase DC-DC converter according to claim 1 or 2, wherein the heat-generating component includes a coil.

11. The multiphase DC-DC converter according to claim 1 or 2, wherein the switch control unit determines whether the temperature measurement by the temperature measuring unit is abnormal based on the difference between the control value for controlling the switch of one DC-DC converter and the control value for controlling the switch of the other DC-DC converter.

Images