WO2020026550A1 - Power supply device and electronic control unit - Google Patents

Abstract

Provided are: a power supply device than can realize reduction of ripples; and an electronic control unit that is provided with the power supply device. A condition setting unit 26 variably sets the number of phases to be enabled from among booster circuits 20a[1] and 20b[2]-20b[n] having n-number of phases, and current threshold values (current upper-limit threshold value IthH and current lower-limit threshold value IthL) of an inductor current of each of the phases, on the basis of a battery power supply voltage (input voltage VI). A current control circuit 24 generates a switching signal SS for a prescribed phase (e.g., the first phase) on the basis of the current threshold values set by the condition setting unit 26.

Description

Power supply and electronic control unit

The present invention relates to a power supply device and an electronic control device, for example, a power supply device that generates a high voltage required for an in-vehicle injector and an electronic control device (ECU: Electronic Control Unit) including the power supply device.

Patent Literature 1 discloses a method of changing an upper limit threshold value of an inductor current for a predetermined phase to a value higher than usual in a predetermined period in a multi-phase DC / DC converter according to a decrease in output voltage. Is shown. Patent Literature 2 discloses a method of switching between the number of phases to be used and an upper limit threshold value of an inductor current according to an engine speed in a multi-phase DC / DC converter mounted on an electronic control unit (ECU). .

US Patent Application Publication No. 2015/0288285 JP 2017-125417 A

For example, an electronic control unit (ECU) that drives an in-vehicle injector is equipped with a boost converter that generates a predetermined high voltage from a battery power supply voltage so that a current exceeding 10 A or the like flows through the injector. In recent years, a multi-phase configuration as shown in Patent Literature 1 or Patent Literature 2 may be used as a boost converter. On the other hand, the battery power supply voltage supplied to the boost converter can change according to various conditions. When the battery power supply voltage changes, in the multi-phase boost converter, the current balance of each phase may be lost, and the ripple may increase.

The present invention has been made in view of such circumstances, and one of its objects is to provide a power supply device capable of reducing ripples and an electronic control device including the power supply device.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

概要 The following is a brief description of an outline of a typical embodiment disclosed in the present application.

The power supply device according to one embodiment includes a multi-phase booster circuit, a condition setting unit, and a current control circuit. The multi-phase booster circuit includes an inductor and a switching element controlled by a switching signal for each phase, boosts a battery power supply voltage supplied from a battery, and supplies the boosted voltage to a load. The condition setting unit variably sets the number of phases to be activated from the booster circuit and the current threshold value of the inductor current in each phase based on the battery power supply voltage. The current control circuit generates a switching signal for a predetermined phase based on a current threshold of the inductor current set by the condition setting unit.

効果 Of the inventions disclosed in the present application, the effect obtained by the representative embodiment will be briefly described.

FIG. 1 is a schematic diagram illustrating a configuration example of a main part of an electronic control device according to a first embodiment of the present invention. FIG. 4 is a waveform chart showing a schematic operation example of the power supply device according to the first embodiment of the present invention. FIG. 3 is a waveform diagram illustrating a schematic operation example different from FIG. 2. FIG. 2 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) according to the first embodiment of the present invention. FIG. 5 is a schematic diagram illustrating a configuration example of a condition setting table provided in a condition setting unit in FIG. 4. FIG. 9 is a schematic diagram illustrating a configuration example of a main part of a power supply device (boost converter) according to a second embodiment of the present invention. FIG. 7 is a waveform diagram illustrating an example of operation contents of the power supply device of FIG. 6. FIG. 7 is a schematic diagram illustrating a configuration example of an initial value table provided in the condition setting unit of FIG. 6. FIG. 7 is a waveform diagram illustrating an operation example of a main part of the power supply device (step-up converter) in FIG. 6. FIG. 9 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) according to a third embodiment of the present invention. It is the schematic which shows the structural example of the principal part of the power supply device (boost converter) which deformed FIG. FIG. 14 is a waveform chart showing a schematic operation example of the power supply device according to Embodiment 4 of the present invention. FIG. 13 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) according to a fourth embodiment of the present invention. FIG. 14 is a schematic diagram illustrating a configuration example of a condition setting table provided in the condition setting unit in FIG. 13. FIG. 14 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) according to a fifth embodiment of the present invention. FIG. 5 is a schematic diagram illustrating a configuration example of a main part around a power supply device (boost converter) as a comparative example of the present invention. FIG. 17 is a waveform diagram illustrating a schematic operation example of the electronic control unit (ECU) of FIG. 1 including the boost converter of FIG. 16. FIG. 17 is a waveform diagram illustrating a schematic operation example of the power supply device of FIG. 16.

In the following embodiments, when necessary for the sake of convenience, the description will be made by dividing into a plurality of sections or embodiments, but unless otherwise specified, they are not unrelated to one another, and one is the other. Some or all of the modifications, details, supplementary explanations and the like are provided. Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, amount, range, etc.), a case where it is particularly specified and a case where it is clearly limited to a specific number in principle, etc. However, the number is not limited to the specific number, and may be more than or less than the specific number.

Furthermore, in the following embodiments, the constituent elements (including element steps, etc.) are not necessarily essential unless otherwise specified or considered to be essential in principle. Needless to say. Similarly, in the following embodiments, when referring to the shapes, positional relationships, and the like of the components, the shapes are substantially the same unless otherwise specified, and in cases where it is clearly considered in principle not to be so. And the like. This is the same for the above numerical values and ranges.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments, the same members are denoted by the same reference numerals in principle, and the repeated description thereof will be omitted.

(Embodiment 1)
《Outline of electronic control unit》
FIG. 1 is a schematic diagram showing a configuration example of a main part of an electronic control device according to Embodiment 1 of the present invention. The electronic control unit 1 illustrated in FIG. 1 is, for example, an ECU that drives an in-vehicle injector. The electronic control unit (ECU) 1 includes, for example, a wiring board on which various components are mounted, and includes an input filter 10, a boost converter (power supply device) 11, a driver 12, a control device 13, and a step-down converter 14. And

The input filter 10 generates the input voltage VI by smoothing the battery power supply voltage VB (typically 12 V) supplied from a battery (not shown). The boost converter 11 boosts the input voltage VI (in other words, the battery power supply voltage VB supplied from the battery via the input filter 10), and uses the boosted voltage as the boosted power supply voltage Vinj (for example, 65 V). Supply to 12. The driver 12 drives a vehicle-mounted injector. Specifically, the driver 12 causes a predetermined injector current (load current) Ild to flow through the solenoid coil Linj of the injector using the boosted power supply voltage Vinj.

(4) The step-down converter 14 generates the internal power supply voltage Vdd (for example, 3.3 V or the like) by stepping down the input voltage VI. The control device 13 is, for example, a microcontroller that operates with the internal power supply voltage Vdd. The control device 13 drives the injector via the driver 12 according to various control signals Sctl from outside the device. Control device 13 controls boost converter 11 as appropriate.

<< Outline and problems of power supply device (comparative example) >>
Here, prior to the description of the power supply device of the first embodiment, a power supply device as a comparative example will be described. FIG. 16 is a schematic diagram showing a configuration example of a main part around a power supply device (boost converter) as a comparative example of the present invention. In FIG. 16, the input filter 10 is configured by, for example, an LC filter or the like. The boost converter (power supply device) 11 ′ includes a multi-phase (n-phase) booster circuit 20a [1], 20b [2] to 20b [n], a current detector 21, and n boost controller 62 [1]. To 62 [n], "n-1" fixed delay units 23 [1], 23 [2],..., 23 [n-1] (not shown), a current control circuit 64, and an output capacitor Co. A boosted power supply voltage Vinj is generated in the output capacitor Co by an n-phase booster circuit.

The booster circuit 20a [1] includes an inductor L [1], a switching element SW [1] whose on / off is controlled by a switching signal SS [1], and a diode D [1] having the output capacitor Co side as a cathode. And a current detection resistor R [1]. When the switching element SW [1] is turned on, the inductor L [1] accumulates power when substantially the input voltage VI is applied to both ends. On the other hand, when the switching element SW [1] is off, the inductor L [1] charges the output capacitor Co via the diode D [1] by the inductor current IL [1] having the accumulated power as an electromotive force. I do. The current detection resistor R [1] converts the inductor current IL [1] flowing through the inductor L [1] into a voltage. The current detector 21 detects the inductor voltage IL [1] by detecting the converted voltage.

Each of the booster circuits 20b [2] to 20b [n] has the same configuration as the booster circuit 20a [1] and performs the same operation, except that the current detection resistor is not provided. That is, the booster circuit 20b [2] includes the inductor L [2] through which the inductor current IL [2] flows, the switching element SW [2] controlled by the switching signal SS [2], and the diode D [2]. And charges the output capacitor Co with the inductor current IL [2]. Similarly, the booster circuit 20b [n] includes an inductor L [n] through which the inductor current IL [n] flows, a switching element SW [n] controlled by a switching signal SS [n], and a diode D [n]. And charges the output capacitor Co with the inductor current IL [n].

The current control circuit 64 generates a switching signal SS for a predetermined phase (here, the first phase) based on a current threshold of an inductor current fixedly set in advance. Specifically, the current control circuit 64 includes a hysteresis comparator CMP that compares the detected current value from the current detector 21 with the upper limit current threshold IthH and the lower limit current threshold IthL. The current control circuit 64 raises the switching signal SS when the detected current value is lower than the lower limit current threshold IthL, and lowers the switching signal SS when the detected current value is higher than the upper limit current threshold IthH. The difference value between the upper limit current threshold IthH and the lower limit current threshold IthL (that is, the hysteresis width) is always kept constant.

The boosting control unit 62 [1] includes, for example, a switch driver and the like, receives the switching signal SS from the current control circuit 64, generates a switching signal SS [1], and uses the switching signal SS [1] to generate the switching signal SS [1]. The switching element SW [1] in [1] is controlled. The fixed delay unit 23 [1] delays the switching signal SS [1] by a predetermined fixed delay time. The boost controller 62 [2] generates the switching signal SS [2] based on the output signal from the fixed delay unit 23 [1].

Thereafter, similarly, the fixed delay unit 23 [n-1] (not shown) delays the switching signal SS [n-1] (not shown) by a predetermined fixed delay time, and increases the voltage of the boosting control unit 62 [n-1]. ] Generates the switching signal SS [n] based on the output signal from the fixed delay unit 23 [n-1]. As described above, the “n−1” fixed delayers 23 [1] to 23 [n−1] delay the switching signal for the immediately preceding phase by the fixed delay time, and delay the switching signal for the immediately preceding phase. Output as a switching signal.

FIG. 17 is a waveform diagram showing a schematic operation example of the electronic control unit (ECU) of FIG. 1 including the boost converter of FIG. The electronic control unit (ECU) 1 of FIG. 1 opens the fuel injection valve by flowing an instantaneous injector current (load current) Ild to the solenoid coil Linj at every predetermined injection interval T1. When the fuel injection valve opens, fuel is injected into the combustion chamber. On the other hand, in order to properly control the fuel injection valve, it is necessary to increase the injector current Ild from zero at a required rising rate to a predetermined current value (for example, 15 A). The rising rate depends on the boosted power supply voltage Vinj. Therefore, the boost converter 11 needs to boost the boosted power supply voltage Vinj to a specified boost value before the injection is performed.

説明 Specifically, as shown in FIG. 17, the boosted power supply voltage Vinj held by the output capacitor Co decreases every time the injector current Ild flows. The boost converter 11 'in FIG. 16 is enabled when the boost power supply voltage Vinj decreases to a predetermined threshold (for example, 63 V) and starts the boost operation. Thereafter, the boost converter 11 'is invalidated when the boosted power supply voltage Vinj returns to a specified boosted value (for example, 65 V or the like) by the boosting operation, and ends the boosting operation. Thereafter, the boosted power supply voltage Vinj is held by the output capacitor Co. The period from the start to the end of the boost operation (in other words, the effective period of the boost converter 11 ') is the boost period T2. The boost period T2 is required to be shorter than the injection interval T1 as described above.

In the boost period T2, the inductor current IL [1] is controlled by the switching signal SS from the current control circuit 64 (equivalent to the switching signal SS [1] from the boost controller 62 [1]). The average value of each of the inductor currents IL [2] to IL [n] is determined by using the switching signals SS [2] to SS [n] having the same duty ratio as the switching signal SS [1]. Control is performed so as to be equal to the average value of IL [1].

Here, the injection interval T1 is generally set to several ms or the like, but may be set to a value of less than 1 ms particularly when the injector performs multi-stage injection. When the injection interval T1 becomes short, it may be difficult to maintain the relationship of the boosting period T2 <the injection interval T1. Therefore, if a multi-phase boost converter 11 ′ as shown in FIG. 16 is used, the charging current of the output capacitor Co can be increased by the number of phases (N) to be enabled, so that the boosting period T2 <injection The relationship of the interval T1 can be easily maintained.

However, the configuration shown in FIG. 16 may cause a problem as shown in FIG. FIG. 18 is a waveform diagram showing a schematic operation example of the power supply device of FIG. The battery power supply voltage VB (and thus the input voltage VI) has a width of, for example, 10 V to 35 V depending on, for example, the internal resistance value of the battery and the output current value of the battery associated with the operation state of each unit in the vehicle. have. When the input voltage VI is low, the boosting period T2 shown in FIG. 17 becomes longer, and the relationship of the boosting period T2 <the injection interval T1 may not be satisfied. Therefore, here, the number of valid phases (N) is set such that the number of phases to be activated (hereinafter referred to as the number of valid phases (N)) is decreased (increased) as the battery power supply voltage VB becomes higher (lower). Consider applying a variable scheme.

FIG. 18 shows the inductor current IL [1] when the input voltage VI is high and the number of effective phases (N) is set to 2 and when the input voltage VI is low and the number of effective phases (N) is set to 3 To IL [3] and the input current Ivb to the boost converter 11 ′. The fixed delay time TdF of each fixed delay unit 23 [1], 23 [2],... And the hysteresis width ΔIthF (= IthH−IthL) of the current control circuit 64 in FIG. When the number (N) is 2, the inductor currents IL [1] and IL [2] are determined so as to be balanced. The fixed delay time TdF and the hysteresis width ΔIthF are always kept constant.

As described above, when the inductor currents IL [1] and IL [2] are balanced, the current ripple of the total inductor current (IL [1] + IL [2]) (and the current ripple of the input current Ivb) is reduced. can do. On the other hand, if the input voltage VI decreases in this state, the number of effective phases (N) changes to 3, and the switching cycle of each phase becomes slower because the slope of the inductor currents IL [1] to IL [3] becomes gentler. Extend. As a result, the current balance of the inductor currents IL [1] to IL [3] is lost, and the current ripple of the input current Ivb increases. In this case, in order to reduce the current ripple, for example, an input filter 10 having a large size is required, and it may be difficult to reduce the size and cost of the electronic control unit (ECU) 1.

Note that, here, the variable method of the number of effective phases (N) is applied, but for example, a method of fixing the number of effective phases (N) to the maximum value (n) regardless of the input voltage VI is also conceivable. In this case, for example, when the input voltage VI is tripled, it is desirable to change the target current of each phase to, for example, about ３. In other words, it is desirable that the input power to the boost converter 11 'is constant to some extent.

This is because if the input power greatly changes, the length of the boosting period T2 also greatly changes, and for example, the boosting power supply voltage Vinj at the start of injection varies due to leakage of the output capacitor Co or the like, which may hinder stable operation of the injector. Because there is. Such a problem can be solved by changing the target current to about 1/3 as described above, but in this case, another problem may occur. That is, when the target current is changed to about 1/3, it is necessary to lower the lower limit current threshold IthL accordingly, and accordingly, a situation may occur in which the lower limit current threshold IthL becomes lower than zero.

In view of the above, it is desirable to apply a variable method of the number of effective phases (N). For example, if the number of effective phases (N) is switched to about 1/3 when the input voltage VI is tripled, the input power can be kept constant to some extent without changing the target current. From such a viewpoint, the target current (the intermediate value between the upper limit current threshold IthH and the lower limit current threshold IthL) Itg2 when the number of effective phases (N) in FIG. 18 is 2 and the target current when the number of effective phases (N) is 3 The target current Itg3 may be the same. However, needless to say, the target current Itg2 and the target current Itg3 can be set to values slightly different from each other.

<< Schematic Operation of Power Supply Device (Embodiment 1) >>
FIG. 2 is a waveform diagram showing a schematic operation example of the power supply device according to the first embodiment of the present invention. FIG. 2 shows the case where the variable method of the number of effective phases (N) described in FIG. 18 is applied. For example, the input voltage is set to such an extent that it is not necessary to switch the number of effective phases (N) such as several V levels. An operation example when VI changes is shown. Here, it is assumed that the number of effective phases (N) is 2, and the input voltage VI is high and low.

First, in order to balance the inductor currents IL [1] and IL [2] of each phase, as can be seen from FIG. 2, the multiplication value “N × TdF” of the number of effective phases (N) and the fixed delay time TdF is obtained. The switching cycle of each phase may be determined as the target switching cycle. In the example of FIG. 2, since the number of effective phases (N) is 2, the switching cycle Tcyc2 of each phase may be set to the target switching cycle “2 × TdF”.

The switching period Tcyc2 is determined by the input voltage VI and the hysteresis width (IthH-IthL). Specifically, the switching cycle Tcyc2 becomes longer as the input voltage VI becomes lower because the slope of the inductor current becomes gentler, and becomes shorter as the hysteresis width becomes narrower. Therefore, if the hysteresis width is reduced so as to offset the extension of the switching cycle Tcyc2 due to the decrease in the input voltage VI, the switching cycle Tcyc2 is maintained at the target switching cycle “2 × TdF” regardless of the input voltage VI. . In the example of FIG. 2, the hysteresis width ΔIth1 is determined when the input voltage VI is high, and the hysteresis width ΔIth2 (<ΔIth1) is determined when the input voltage VI is low.

FIG. 3 is a waveform diagram showing a schematic operation example different from FIG. FIG. 3 shows an operation example in a case where the input voltage VI changes to such an extent that it is necessary to switch the number of effective phases (N) such as 6 V or more, unlike FIG. Here, as in the case of FIG. 18, the case where the input voltage VI is high and the number of effective phases (N) is set to 2 and the case where the input voltage VI is low and the number of effective phases (N) are set to 3 Assume the case. When the number of effective phases (N) is 2, the switching cycle Tcyc2 of each phase may be set to the target switching cycle “2 × TdF” as in the case of FIG. When the number of effective phases (N) is 3, the switching cycle Tcyc3 of each phase may be set to the target switching cycle “3 × TdF”.

Here, switching the number of effective phases (N) from 2 to 3 means that the input voltage VI has decreased to some extent, and when the input voltage VI decreases, the switching cycle Tcyc3 of each phase becomes longer. When the number of effective phases (N) is switched from 2 to 3, the target switching period itself becomes longer by “TdF”. Therefore, taking into account the extension of the switching cycle Tcyc3 due to the decrease in the input voltage VI and the extension of the target switching cycle due to the increase in the number of effective phases (N), the switching cycle Tcyc3 is set to the target switching cycle “3 × TdF”. ”Is determined. In the example of FIG. 3, the hysteresis width ΔIth1 is determined when the number of effective phases (N) is 2, and the hysteresis width ΔIth3 (≠ ΔIth1) is determined when the number of effective phases (N) is 3.

As described above, by applying the variable method of the number of effective phases (N), it is possible to keep the input power to the power supply device (the boost converter) substantially constant as described in FIG. On the premise, as shown in FIGS. 2 and 3, the hysteresis width is variably set in addition to the number of effective phases (N) in accordance with the input voltage VI, so that the inductor of each phase is independent of the input voltage VI. The currents IL [1] to IL [n] can be balanced. As a result, the ripple of the input current Ivb can be reduced. Accordingly, the size of the input filter 10 can be reduced, and the electronic control unit (ECU) 1 can be reduced in size and cost.

<< Schematic Configuration of Power Supply Device (Embodiment 1) >>
FIG. 4 is a schematic diagram showing a configuration example of a main part of the power supply device (boost converter) according to the first embodiment of the present invention. FIG. 5 is a schematic diagram showing a configuration example of a condition setting table provided in the condition setting unit in FIG. The power supply device (boost converter) 11a shown in FIG. 4 is applied to the boost converter 11 of FIG. The boost converter 11a differs from the configuration example of FIG. 16 in the following point. First, a boost execution control unit 25, a condition setting unit 26, and voltage detectors 27 and 28 are added. Also, the configurations of the current control circuit 24 and the n boost control units 22 [1] to 22 [n] are slightly changed.

(4) The voltage detector 27 detects the boosted power supply voltage Vinj, and the voltage detector 28 detects the input voltage VI. The boosting execution control unit 25 responds to the boosting enable signal UCEN from the outside (for example, the control device 13 in FIG. 1) and the boosting power supply voltage Vinj detected by the voltage detector 27 to increase the boosting control unit 22 [1]. And outputs an enable signal EN [1] to the CPU. For example, when the boost enable signal UCEN is at the negated level, the boost execution control unit 25 keeps the enable signal EN [1] at the negated level.

On the other hand, when the boost enable signal UCEN is at the assert level, the boost execution control unit 25 controls the enable signal EN [1] using a hysteresis comparator or the like. Specifically, as shown in FIG. 17, when the boosted power supply voltage Vinj is lower than the lower limit voltage threshold VthL (eg, 63 V), the boosting execution control unit 25 asserts the enable signal EN [1] to increase the boosted voltage. Start the operation. When the boost power supply voltage Vinj is higher than the upper limit voltage threshold VthH (for example, 65 V), the boost execution control unit 25 negates the enable signal EN [1] to end the boost operation.

The condition setting unit 26 activates the voltage boosting circuits 20a [1] and 20b [2] to 20b [n] based on the input voltage VI (and the battery power supply voltage VB) detected by the voltage detector 28. The number of phases (that is, the number of effective phases (N)) and the current threshold of the inductor current of each phase are variably set. Specifically, the condition setting unit 26 includes a condition setting table CTBLa as shown in FIG. The condition setting table CTBLa includes correspondences between the input voltage VI (therefore, the battery power supply voltage VB), the number of effective phases (N), and the current threshold of the inductor current (specifically, the upper limit current threshold IthH and the lower limit current threshold IthL). The relationship is held in advance.

In the example of FIG. 5, for example, when the input voltage VI is 10 V or more and less than 16 V, the number of effective phases (N) is determined to be 5. When the input voltage VI is 16 V or more and less than 22 V, the number of effective phases (N) is set. Is set to 4. That is, the number of effective phases (N) is set to decrease as the battery power supply voltage VB increases. Then, according to the combination of the input voltage VI and the number of effective phases (N), as shown in FIGS. 2 and 3, the switching cycle is set to “N × TdF” (TdF is a fixed delay time). An upper limit current threshold IthH and a lower limit current threshold IthL of the inductor current are determined.

For example, when the number of effective phases (N) is 5, each value in FIG. 5 has a relationship of “I1H-I1L” <“I2H-I2L” <“I3H-I3L” as can be seen from FIG. It should be noted that specific values in the condition setting table CTBLa are actually determined in advance using simulation or the like. Further, the condition setting unit 26 outputs enable signals EN [2] to EN [n] to the boost control units 22 [2] to 22 [n] according to the number of valid phases (N).

The current control circuit 24 includes a hysteresis comparator CMP similar to that of FIG. However, the upper limit current threshold IthH and the lower limit current threshold IthL of the hysteresis comparator CMP are not fixed as in the case of FIG. 16, but are variably set by the condition setting unit 26. The boost control units 22 [1] to 22 [n] perform AND operation of, for example, a switching signal from the current control circuit 24 or the fixed delay unit of the immediately preceding phase and an enable signal from the condition setting unit 26. It includes a gate and a switch driver provided at a subsequent stage.

{As a specific operation example, for example, it is assumed that the condition setting unit 26 detects the input voltage VI of 18 V using the voltage detector 28. In this case, the condition setting unit 26 sets the number of valid phases (N) to 4 based on the condition setting table CTBLa in FIG. 5, asserts enable signals EN [2] to EN [4] (not shown), and enables The signals EN [5] (not shown) to EN [n] are negated. Accordingly, the boost control units 22 [5] (not shown) to 22 [n] fix the switching signals SS [5] (not shown) to SS [n] at the off level.

The condition setting unit 26 outputs “I5H” as the upper limit current threshold IthH and “I5L” as the lower limit current threshold IthL to the current control circuit 24 based on the condition setting table CTBLa. The current control circuit 24 generates the switching signal SS by comparing the “I5H” and “I5L” with the inductor current IL [1] detected by the current detector 21. The boost controller 22 [1] receives the switching signal SS and generates a switching signal SS [1]. The switching signal SS [1] is sequentially delayed by fixed delay units 23 [1] to 23 [3] (not shown), and the boost control units 22 [2] to 22 [4] (not shown) are delayed. The switching signals SS [2] to SS [4] (not shown) are sequentially generated based on the received signals.

Each unit except for the booster circuits 20a [1], 20b [2] to 20b [n] and the output capacitor Co in FIG. 4 may be constituted by a dedicated circuit. Control device 13). In the latter case, the current detector 21 and the voltage detectors 27 and 28 can be realized by an analog-digital converter or a configuration in which a voltage dividing resistor is added thereto. The current control circuit 24 and the boost execution control unit 25 can be realized by, for example, a digital comparator based on software processing. The boost control units 22 [1] to 22 [n] can be realized by software processing, and the fixed delay units 23 [1], 23 [2],... Can be realized by using a timer circuit or the like. The condition setting unit 26 can be realized by, for example, a combination of a nonvolatile memory that stores the condition setting table CTBLa and software processing.

<< Main effects of Embodiment 1 >>
As described above, by using the method of the first embodiment, typically, reduction of ripples can be realized regardless of battery power supply voltage VB. Accordingly, the size of the input filter 10 can be reduced, and the electronic control unit (ECU) 1 can be reduced in size and cost.

Here, the current threshold value (upper limit current threshold value IthH and lower limit current threshold value IthL) for each input voltage VI is determined using the condition setting table CTBLa, but in some cases, an arithmetic expression using the input voltage VI as a parameter is used. It is also possible to determine the current threshold value by using That is, as can be seen from FIG. 2, if the number of effective phases (N) does not change, the hysteresis width may be changed to some extent regularly in accordance with the input voltage VI. It is possible.

In addition, here, the condition setting unit 26 variably sets both the upper limit current threshold IthH and the lower limit current threshold IthL as the current threshold. However, in some cases, a method of variably setting either one may be used. That is, in principle, the switching cycle can be changed by variably setting either one. For example, in a case where the switching cycle and the target current are changed according to the input voltage VI, one of them may be variably set. Further, the condition setting table CTBLa may be configured to determine, for example, a target current and a hysteresis width, instead of the upper limit current threshold IthH and the lower limit current threshold IthL.

(Embodiment 2)
<< Outline of Power Supply Device (Embodiment 2) >>
FIG. 6 is a schematic diagram illustrating a configuration example of a main part of a power supply device (boost converter) according to a second embodiment of the present invention. FIG. 7 is a waveform diagram showing an example of the operation content of the power supply device of FIG. The power supply device (boost converter) 11b shown in FIG. 6 is different from the configuration example of FIG. 4 in the following point. First, in FIG. 6, a phase comparator 35 is provided, and a fixed delay unit 23 [n] is added. In FIG. 6, the voltage detector 28 is not provided, and instead, a condition setting unit 36 to which the number of effective phases (N) is input is provided. For example, the control device 13 of FIG. 1 determines the number of effective phases (N) by monitoring the battery power supply voltage VB, and notifies the condition setting unit 36.

The fixed delay unit 23 [n] delays the switching signal SS [n] by a fixed delay time. The phase comparator 35 converts the signal phase PHr of the switching signal SS [1] for the first phase and the switching signal SS [N] for the Nth (N: number of valid phases) phase by the fixed delay unit 23 [N]. A phase error with the delayed signal phase PHd [N] is sequentially detected. The condition setting unit 36 sequentially and variably controls the current thresholds (for example, the upper current threshold IthH and the lower current threshold IthL) such that the phase error by the phase comparator 35 approaches zero.

As shown in FIG. 7, for example, when N = 3, the signal phase PHr of the switching signal SS [1] and the switching signal SS [3] after being delayed by the fixed delay unit (23 [3]). The phase error with the signal phase PHd [3] may be zero. This state is a state where the inductor currents IL [1] to IL [3] are balanced by setting the switching cycle to the target switching cycle “N × TdF” (TdF: fixed delay time). The condition setting unit 36 searches for a current threshold value (in other words, a switching cycle) that causes this state by feedback control using the phase comparator 35.

FIG. 8 is a schematic diagram showing a configuration example of an initial value table provided in the condition setting unit of FIG. FIG. 9 is a waveform diagram showing an operation example of a main part of the power supply device (step-up converter) of FIG. For example, as shown in FIG. 8, the condition setting unit 36 is provided with an initial value table ITBL in which initial values of an upper limit current threshold IthH and a lower limit current threshold IthL are determined for each valid phase number (N). The upper limit current threshold IthH and the lower limit current threshold IthL in the initial value table ITBL determine a target current for each number of effective phases (N) by an intermediate value. Further, the hysteresis width (IthH-IthL) is set in advance to a value estimated to be close to the convergence value of the search operation to some extent by simulation or the like. The condition setting unit 36 determines an initial value of the search operation based on the initial value table ITBL.

In FIG. 9, at time t1, the signal phase PHd [3] rises, and at time t2, the signal phase PHr rises. The phase comparator 35 detects a rising edge of the signal phases PHr and PHd [3], and indicates a phase delay indicating that the signal phase PHr is behind the signal phase PHd [3] in a period from time t1 to time t2. A detection signal (phase error signal) DWN is output. The condition setting unit 36 reduces the hysteresis width (IthH-IthL) by a preset unit step width (2ΔI) without changing the target current Itg according to the phase delay detection signal DWN. As a result, the switching cycle of the switching signal SS [1] (in other words, the signal phase PHr) is shortened, and the phase error is controlled to approach zero.

On the other hand, at time t5, the signal phase PHr rises, and at time t6, the signal phase PHd [3] rises. In response, phase comparator 35 outputs a phase lead detection signal (phase error signal) UP indicating that signal phase PHr is ahead of signal phase PHd [3] during a period from time t5 to time t6. I do. The condition setting unit 36 increases the hysteresis width by a preset unit step width (2ΔI) without changing the target current Itg according to the phase advance detection signal UP. As a result, the switching cycle of the switching signal SS [1] (signal phase PHr) is lengthened, and the phase error is controlled to approach zero. The phase comparator 35 and the condition setting unit 36 execute such feedback control at every predetermined control cycle (in this example, every two switching cycles).

<< Main effects of the second embodiment and comparison with each embodiment >>
As described above, by using the method of the second embodiment, the same effects as the various effects described in the first embodiment can be obtained. In addition, since the current threshold (in other words, the switching cycle) is controlled based on the observation, the switching cycle can be set to the target switching cycle with higher accuracy than in the method of the first embodiment. As a result, it is possible to further reduce the ripple. On the other hand, since the feedback control requires a certain amount of time to converge as compared with the method of the first embodiment, the method of the first embodiment is useful from this viewpoint.

(Embodiment 3)
<< Outline of Power Supply Device (Embodiment 3) >>
FIG. 10 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) according to a third embodiment of the present invention. The power supply device (step-up converter) 11c shown in FIG. 10 includes a pulse width measuring device 40 and an input voltage estimator 41 as compared with the configuration example in FIG. A part 46 is provided.

The input voltage estimator 41 estimates the input voltage VI based on the inductor current IL [1] detected by the current detector 21. More specifically, for example, the rate of change of the inductor current IL [1] when the switching element SW [1] is turned on depends on the input voltage VI. Therefore, the input voltage estimator 41 can estimate the input voltage VI based on the change rate of the inductor current IL [1] detected by the current detector 21.

The pulse width measuring device 40 measures the pulse width of the phase delay detection signal DWN from the phase comparator 35, and outputs a phase delay amount detection signal NDWN representing the magnitude. Similarly, the pulse width measuring device 40 measures the pulse width of the phase lead detection signal UP from the phase comparator 35 and outputs a phase lead amount detection signal NUP representing the magnitude. The condition setting unit 46 includes, for example, an initial value table having a configuration as shown in the condition setting table CTBLa in FIG. 5, instead of the initial value table ITBL as shown in FIG. The condition setting unit 46 determines the initial values of the current thresholds (the upper limit current threshold IthH and the lower limit current threshold IthL) by referring to the initial value table based on the input voltage VI estimated by the input voltage estimator 41.

Further, the condition setting unit 46 determines the number of steps (K) based on the unit step width (2ΔI) according to the phase delay amount detection signal NDWN from the pulse width measuring device 40, and sets the hysteresis width (IthH−IthL). Narrow by “K × 2ΔI”. Similarly, the condition setting unit 46 determines the number of steps (K) according to the phase lead amount detection signal NUP from the pulse width measuring device 40, and widens the hysteresis width by “K × 2ΔI”. Thereby, the hysteresis width in FIG. 9 is relatively narrowed, for example, in accordance with the phase delay detection signal DWN in the period from time t1 to time t2, and in accordance with the phase advance detection signal UP in the period from time t5 to time t6. Will be relatively small.

FIG. 11 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) obtained by modifying FIG. A power supply device (boost converter) 11d shown in FIG. 11 includes a voltage detector 28 as shown in FIG. 4 instead of the input voltage estimator 41 in FIG. The voltage detector 28 includes, for example, an external resistor element for dividing the input voltage VI and an analog-to-digital converter for detecting the divided voltage value. On the other hand, the input voltage estimator 41 is configured by, for example, a calculator. For this reason, for example, as described in FIG. 4, when each unit is mainly mounted on a microcontroller or the like, the input voltage estimator 41 is used from the viewpoint of reducing external components and resources of the analog-to-digital converter. It is desirable to provide. On the other hand, from the viewpoint of voltage detection accuracy, it is desirable to provide the voltage detector 28.

<< Main effects of Embodiment 3 and comparison with Embodiments >>
As described above, by using the method of the third embodiment, the same effects as the various effects described in the second embodiment can be obtained. Further, as compared with the method of the second embodiment, since the control amount of the hysteresis width can be adjusted according to the amount of the phase error, the time required for the feedback control to converge can be reduced. Furthermore, by setting the initial value in the condition setting unit 46 for each input voltage VI, the accuracy of the initial value is further increased, and as a result, the convergence time of the feedback control can be shortened and the ripple can be further reduced.

That is, in this case, at the stage of the initial value, the state becomes somewhat close to the ideal, and by adding the feedback control to the state, the control that further approximates the ideal is performed. From this viewpoint, it is desirable that the unit step width (2ΔI) is set to a sufficiently small value, and that the resolution of the pulse width measuring device 40 is also sufficiently high. As a modification, a configuration in which only the pulse width measuring device 40 in FIG. 10 is added to the configuration in FIG. 6 can be used. Also in this case, the convergence time of the feedback control can be shortened.

(Embodiment 4)
<< Schematic Operation of Power Supply Device (Embodiment 4) >>
FIG. 12 is a waveform chart showing a schematic operation example of the power supply device according to the fourth embodiment of the present invention. FIG. 12 shows an operation example in the case where the input voltage VI changes to such an extent that the number of effective phases (N) needs to be switched, as in the case of FIG. Here, similarly to the case of FIG. 3, the case where the input voltage VI is high and the number of effective phases (N) is set to 2 and the case where the input voltage VI is low and the number of effective phases (N) are 3 are set. Assume the case.

In FIG. 3, assuming that the delay time between the phases is fixed, the current threshold value of the inductor current is variably set, so that “Tcyc = N × TdF” (Tcyc: switching cycle, N: number of effective phases, A switching cycle Tcyc that satisfies the relationship of TdF (fixed delay time) has been determined. On the other hand, in FIG. 12, the delay time between the phases is variably set on the assumption that the current threshold value of the inductor current is fixed. When the current threshold is fixed, the switching cycle changes according to the input voltage VI. However, if the delay time is variably set according to the change in the switching cycle Tcyc, the above-described relationship can be satisfied.

Specifically, when the variable delay time is “TdV” and the switching cycle that changes according to the input voltage VI is “Tcyc”, the variable delay time TdV is variably set so as to satisfy “Tcyc = N × TdV”. do it. In the example of FIG. 12, the hysteresis width ΔIthF is the same between N = 2 and N = 3. The switching cycle Tcyc2 when N = 2 is automatically determined according to the hysteresis width ΔIthF and the input voltage VI, and the switching cycle Tcyc3 when N = 3 is automatically determined.

Here, if the variable delay time TdV1 is variably set, the switching cycle Tcyc2 in the case of N = 2 can satisfy “Tcyc2 = 2 × TdV1”. If the variable delay time TdV2 is variably set, the switching cycle Tcyc3 in the case of N = 3 can satisfy “Tcyc3 = 3 × TdV2”. As a result, as shown in FIG. 12, regardless of the input voltage VI (and the number of phases (N)), the inductor currents IL [1] to IL [3] of each phase can be balanced, and the input current Ivb Can be reduced.

<< Schematic Configuration of Power Supply Device (Embodiment 4) >>
FIG. 13 is a schematic diagram showing a configuration example of a main part of a power supply device (boost converter) according to a fourth embodiment of the present invention. FIG. 14 is a schematic diagram showing a configuration example of a condition setting table provided in the condition setting unit in FIG. In the power supply device (step-up converter) 11e shown in FIG. 13, a variable delay device 43 [1] is used instead of the fixed delay devices 23 [1] to 23 [n-1] (not shown) as compared with the configuration example of FIG. To 43 [n-1] (not shown), and a current control circuit 54 and a condition setting unit 56 different from those in FIG. The “n−1” variable delay devices 43 [1] to 43 [n−1] delay the switching signal for the immediately preceding phase by the variable delay time TdV, as in the case of the fixed delay device. Output as a switching signal for the next phase.

The current control circuit 54 has, for example, the same configuration as the current control circuit 64 in FIG. However, the current control circuit 54 may be configured to change the intermediate value (target current) without changing the hysteresis width (IthH-IthL) according to the number of effective phases (N) from the condition setting unit 56. Good. As in the case of FIG. 4, the condition setting unit 56 sets the booster circuits 20a [1], 20b [2] to 20b [20] based on the input voltage VI (and thus the battery power supply voltage VB) detected by the voltage detector 28. n], the number of phases to be activated (that is, the number of valid phases (N)) is variably set. Also, unlike the case of FIG. 4, the condition setting unit 56 variably sets the variable delay times TdV of the variable delay units 43 [1] to 43 [n-1] based on the input voltage VI.

Specifically, the condition setting unit 56 includes a condition setting table CTBLb as shown in FIG. The condition setting table CTBLb holds in advance a correspondence relationship among the input voltage VI (and, consequently, the battery power supply voltage VB), the number of effective phases (N), and the variable delay time TdV. In FIG. 14, for example, when the number of effective phases (N) is 5, the higher the input voltage VI, the shorter the switching period. Therefore, each value in FIG. 14 has a relationship of T1> T2> T3. It should be noted that specific values in the condition setting table CTBLb are actually determined in advance using simulation or the like.

<< Main effects of Embodiment 4 and comparison with each embodiment >>
As described above, by using the method of the fourth embodiment, the same effects as the various effects described in the first embodiment can be obtained. Further, in the relationship of “Tcyc = N × Td” (Tcyc: switching cycle, N: number of effective phases, Td: delay time), the method of the first embodiment uses “Tcyc” such that “N × Td”. In contrast to this, the method of the fourth embodiment is a method of controlling “Td” so as to be “Tcyc / N”. Due to the difference between the methods, the switching noise occurs at a limited frequency in the method of the first embodiment, but may occur in a wide frequency band in the method of the third embodiment. Therefore, the method of the first embodiment is useful from the viewpoint of easily removing the switching noise. Further, with the difference between the fixed delay unit and the variable delay unit, the method of the first embodiment is useful from the viewpoint of the rotation area. On the other hand, in applications where the change of the hysteresis width is not preferred, the method of the fourth embodiment is useful.

(Embodiment 5)
<< Outline of Power Supply Device (Embodiment 5) >>
FIG. 15 is a schematic diagram showing a configuration example of a main part of a power supply device (step-up converter) according to the fifth embodiment of the present invention. In the power supply device (boost converter) 11f shown in FIG. 15, a boost period setting unit 67 is provided in the condition setting unit 66 as compared with the configuration example in FIG. The boosting period setting section 67 shifts the current threshold value of the inductor current variably set based on the condition setting table CTBLa by an amount corresponding to the set value of the boosting period T2 input from the outside.

In FIG. 17, if the injection interval T1 is changed, the boosting period T2 must be changed accordingly. For example, when shortening the boosting period T2, the target current may be increased by that amount. Therefore, the boosting period setting unit 67 shifts the current thresholds (for example, the upper limit current threshold IthH and the lower limit current threshold IthH) based on the condition setting table CTBLa by an amount corresponding to the set value of the boosting period T2 while maintaining the hysteresis width. I do. As a result, the boosting period setting section 67 variably sets the target current (hence, the boosting period T2).

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the gist of the invention. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described above. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment. . In addition, for a part of the configuration of each embodiment, it is possible to add, delete, or replace another configuration.

For example, the method of the fourth embodiment can be combined with the method of the second or third embodiment. Further, the power supply device according to each of the embodiments is not limited to the in-vehicle ECU, and can be widely applied as a ripple reduction technology to various multi-phase boost converters whose input voltage VI can change. In some cases, the present invention can be similarly applied to a multi-phase step-down converter.

1 Electronic control unit (ECU)
10 Input filter 11 Power supply unit (boost converter)
12 Driver 20a, 20b Booster circuit 23 Fixed delay unit 24 Power control circuit 26, 36, 46, 56, 66 Condition setting unit 35 Phase comparator 43 Variable delay unit 67 Boost period setting unit CMP Hysteresis comparator CTBL Condition setting table D Diode EN Enable signal IL Inductor current IthH Upper current threshold IthL Lower current threshold L Inductor Linj Solenoid coil N Number of phases to be activated PH Signal phase SS Switching signal SW Switching element T2 Boost period Tcyc Switching cycle TdF Fixed delay time TdV Variable delay time VB Battery power supply Voltage VI Input voltage Vinj Boost power supply voltage

Claims (15)

1. A multi-phase booster circuit including an inductor, and a switching element controlled by a switching signal for each phase, boosting a battery power supply voltage supplied from a battery, and supplying the boosted voltage to a load;
   A condition setting unit configured to variably set the number of phases to be activated from the booster circuit based on the battery power supply voltage and a current threshold value of an inductor current of each phase;
   A current control circuit that generates the switching signal for a predetermined phase based on a current threshold value of the inductor current set by the condition setting unit;
   Power supply device having a.
2. The power supply device according to claim 1,
   Further, a plurality of fixed delay units that delay the switching signal for the previous phase by a fixed delay time and output the switching signal as the switching signal for the next phase,
   Power supply.
3. The power supply device according to claim 2,
   The condition setting unit variably sets an upper limit current threshold and a lower limit current threshold as a current threshold of the inductor current,
   Power supply.
4. The power supply device according to claim 2,
   The condition setting unit sets the number of enabled phases to be reduced as the battery power supply voltage increases,
   Power supply.
5. The power supply device according to claim 4,
   The condition setting unit sets the fixed delay time to “TdF”, sets the number of phases to be enabled to “N”, and sets a current threshold value of the inductor current such that a switching cycle of the switching signal becomes “N × TdF”. Variably set,
   Power supply.
6. The power supply device according to claim 5,
   The condition setting unit includes a condition setting table that holds a correspondence relationship between the battery power supply voltage, the number of phases to be activated, and a current threshold value of the inductor current in advance.
   Power supply.
7. The power supply device according to claim 5, further comprising:
   A phase comparator for sequentially detecting a phase error between a signal phase of the switching signal for the first phase and a signal phase after delaying the switching signal for the Nth phase by the fixed delay device;
   The condition setting unit sequentially controls the current threshold so that the phase error by the phase comparator approaches zero,
   Power supply.
8. The power supply device according to claim 2,
   The condition setting unit further includes a boosting period setting unit that shifts the current threshold value of the variably set inductor current by an amount corresponding to a set value of the input boosting period.
   Power supply.
9. A multi-phase booster circuit including an inductor, and a switching element controlled by a switching signal for each phase, boosting a battery power supply voltage supplied from a battery, and supplying the boosted voltage to a load;
   A plurality of variable delay units that delay the switching signal for the immediately preceding phase by a variable delay time and output the switching signal for the immediately succeeding phase as the switching signal;
   A condition setting unit that variably sets the number of phases to be activated from the booster circuit and the variable delay time based on the battery power supply voltage;
   A current control circuit that generates the switching signal for a predetermined phase based on a current threshold of an inductor current that is fixedly set in advance;
   Power supply device having a.
10. The power supply device according to claim 9,
    The condition setting unit sets the number of enabled phases to be reduced as the battery power supply voltage increases,
    Power supply.
11. The power supply device according to claim 10,
    The condition setting unit sets the variable delay time to “TdV”, sets the number of enabled phases to “N”, sets a switching cycle of the switching signal that changes according to the battery power supply voltage to “Tcyc”, Variably setting the variable delay time so as to satisfy Tcyc = N × TdV ″,
    Power supply.
12. The power supply device according to claim 11,
    The condition setting unit includes a condition setting table that previously holds a correspondence relationship between the battery power supply voltage, the number of phases to be activated, and the variable delay time,
    Power supply.
13. An input filter for smoothing a battery power supply voltage supplied from a battery,
    A driver for driving an in-vehicle injector;
    An inductor and a switching element controlled by a switching signal for each phase, boosting the battery power supply voltage supplied from the battery via the input filter, and supplying the boosted voltage to the driver as a power supply voltage Multi-phase booster circuit
    A plurality of fixed delay units that delay the switching signal for the previous phase by a fixed delay time and output the switching signal as the switching signal for the next phase;
    A condition setting unit configured to variably set the number of phases to be activated from the booster circuit based on the battery power supply voltage and a current threshold value of an inductor current of each phase;
    A current control circuit that generates the switching signal for a predetermined phase based on a current threshold value of the inductor current set by the condition setting unit;
    Electronic control device having
14. The electronic control device according to claim 13,
    The condition setting unit variably sets an upper limit current threshold and a lower limit current threshold as a current threshold of the inductor current,
    Electronic control unit.
15. The electronic control device according to claim 14,
    The condition setting unit sets the number of enabled phases to be reduced as the battery power supply voltage increases,
    Electronic control unit.

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