WO2019087746A1 - Power supply switching circuit, power supply ic and in-vehicle electronic control device - Google Patents

Power supply switching circuit, power supply ic and in-vehicle electronic control device Download PDF

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Publication number
WO2019087746A1
WO2019087746A1 PCT/JP2018/038250 JP2018038250W WO2019087746A1 WO 2019087746 A1 WO2019087746 A1 WO 2019087746A1 JP 2018038250 W JP2018038250 W JP 2018038250W WO 2019087746 A1 WO2019087746 A1 WO 2019087746A1
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Prior art keywords
power supply
voltage
switching circuit
circuit
diode
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PCT/JP2018/038250
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French (fr)
Japanese (ja)
Inventor
昌宏 土肥
純之 荒田
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日立オートモティブシステムズ株式会社
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Priority to JP2019551011A priority Critical patent/JP6845945B2/en
Publication of WO2019087746A1 publication Critical patent/WO2019087746A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/10—Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load

Definitions

  • the present invention relates to a power supply switching circuit, a power supply IC, and an on-vehicle electronic control device.
  • a semiconductor integrated circuit IC (Integrated Circuit) mounted on an electronic control device is advanced in function and integration, and power consumption is increased accordingly, and loss and heat generation are increased. If the heat generation of the semiconductor increases, an expensive low thermal resistance package is required to dissipate the heat, or the heat dissipation structure of the substrate or housing on which the semiconductor is mounted or the cost increase of the heat dissipation material may be caused. An issue arises. In order to minimize the cost for these heat dissipation measures, it is required to reduce the power consumption and heat generation of the semiconductor.
  • microcomputers microcomputers
  • ICs mounted therein are becoming highly functional and highly integrated, and power consumption is also increasing.
  • a large power consumption for driving a large current is required for a power supply IC for generating a power supply of a microcomputer and a driver IC for driving an actuator load.
  • the power consumption of these ICs can be roughly divided into power consumption by drive current for microcomputer power generation and actuator drive, and power consumption of an internal power supply circuit for driving and signal processing DCDC power supply and driver circuits.
  • the power consumption of the internal power supply circuit was small in proportion to the power consumption of the entire IC, so the reduction effect of the power consumption of the internal power supply circuit was small.
  • the power consumption and heat generation ratio of the internal power supply circuit are increasing and the influence is increasing as the function and integration of ICs are advanced.
  • the on-vehicle electronic control device there is a battery as a main power source to be supplied, and this battery voltage is directly or step down and boosted to generate a desired voltage required for control.
  • this battery voltage is directly or step down and boosted to generate a desired voltage required for control.
  • it is generally considered to lower the applied voltage or the consumed current, and if the current consumption is constant, the power consumption can be reduced by lowering the driving voltage. It becomes possible.
  • the function of the internal power supply circuit of the power supply IC is a reference voltage in the IC, generation of a reference clock, DCDC power supplies, driving of each driver circuit, communication function with a microcomputer, and the like. Therefore, when the internal circuit is driven with a voltage stepped down from the battery voltage by the DCDC power supply, the internal power supply circuit is first driven by the battery. After that, it is necessary to supply a voltage stepped down by the DCDC power supply to the internal power supply circuit, and a circuit to switch the battery voltage and the stepped-down voltage is needed.
  • FIG. 7 is a block diagram of the power supply switching circuit described in Patent Document 1. As shown in FIG. When applied to a FlexRay transceiver IC, V102 corresponds to the battery voltage VBAT, and V101 corresponds to the VCC power supply voltage. When the VCC power supply voltage is lower than a predetermined voltage, power is supplied from V 102 by activating the PMOS 105.
  • the power supply circuit of FIG. 7 realizes a power supply switching circuit that operates properly, with no current other than the current flowing through the transceiver IC flowing even in the low power consumption mode.
  • the output voltage of the switching circuit described in Patent Document 1 described above is a voltage obtained by reducing the forward voltage of each of the diodes from V101 and V102. That is, this output voltage depends on the voltages of V101 and V102, and when the voltage difference is large, the output voltage to be switched also largely fluctuates.
  • the internal power supply circuit of the integrated circuit needs to constantly generate a reference voltage and a reference clock stably. However, if switching causes a large voltage fluctuation or a momentary voltage drop, the reference voltage or reference clock fluctuation, or the output of the internal power supply circuit decreases, which causes a problem in stable operation at switching. There is.
  • the object of the present invention is to switch the first power supply and the second power supply according to the voltage of the second power supply and to output a voltage independent of the voltage of the first power supply using the first power supply, etc. To provide.
  • the present invention is connected to a first node connecting a current path connected to a first power supply and a current path connected to a second power supply supplying a voltage lower than the first power supply.
  • Output terminal a resistor connected to the first power supply, a Zener diode connected in series to the resistor, and a control electrode connected to a second node connecting the resistor and the Zener diode.
  • FIG. 6 is a circuit diagram showing a configuration of a power supply switching circuit described in Patent Document 1.
  • An object of the present embodiment is to continuously operate the internal power supply circuit stably at the time of switching the power supply and to reduce the power consumption of the internal power supply circuit by switching the power supply.
  • FIG. 1 is a circuit diagram of a power supply switching circuit 12 according to a first embodiment of the present invention.
  • the power supply switching circuit 12 of FIG. 1 includes a Zener diode 22, a resistor 20, an NMOS 23 (N-channel Metal Oxide Semiconductor), and a second diode 24.
  • the output terminal OUT is connected to a first node 26 connecting a current path connected to the first power supply V1 and a current path connected to the second power supply V2 supplying a voltage lower than that of the first power supply V1.
  • Ru The resistor 20 is connected to the first power supply V1.
  • the zener diode 22 is connected in series to the resistor 20.
  • the NMOS 23 transistor
  • the NMOS 23 has a gate (control electrode) connected to the second node 27 connecting the resistor 20 and the Zener diode 22, and according to the voltage applied to the gate, the first power supply V1 and the output terminal Turn on / off the current path between OUT.
  • the second diode 24 rectifies the current flowing in the current path between the second power supply V2 and the output terminal OUT.
  • the rise of the voltage of the second node 27 activates the NMOS 23, and the first node 26 is biased in accordance with the voltage between the gate and the source of the NMOS 23. Thus, the voltage is output to the first node 26 by the supply of the first power supply V1. At this time, the second diode 24 has a backflow prevention function.
  • the voltage V3 is a voltage for driving the internal power supply circuit 13, and has to be higher than the output voltage of the internal power supply circuit 13. By the supply of the voltage V3, the internal power supply circuit 13 generates an output voltage V4.
  • the first node voltage V3B becomes a voltage V2-Vf2 and is supplied from the second power supply V2, and the power supply of V3 is switched from the first power supply V1 to the second power supply V2.
  • the voltage V3A0 In order to switch to the second power supply V2, the voltage V3A0 needs to be set lower than the voltage V2-Vf2.
  • the power consumption of the internal power supply circuit 13 is current I3
  • the power consumption is switched from V1 ⁇ I3 at the time of supplying the first power supply V1 to V2 ⁇ I3 at the time of supplying the second power supply V2, and the second power supply V2 is By lowering it, the power consumption of the internal power supply circuit and the heat generation associated therewith can be reduced.
  • FIG. 2 is a circuit diagram of a power supply switching circuit 12A according to a first modification of the first embodiment of the present invention.
  • the power supply switching circuit 12 shown in FIG. 1 has a configuration in which a second capacitor 25 disposed between the first node 26 and the internal power supply circuit 13 is added. That is, one end of the second capacitor 25 is connected to the output terminal OUT.
  • FIG. 3 is a circuit diagram of a power supply switching circuit 12B according to a second modification of the first embodiment of the present invention.
  • the configuration is such that the first diode 21 disposed between the second node 27 and the Zener diode 22 is added to the power supply switching circuit 12A shown in FIG. That is, the first diode 21 has an anode connected to the second node 27 and a cathode connected to the cathode of the zener diode 22.
  • the first diode 21 cancels the negative temperature characteristic of the voltage of the NMOS 23 (transistor).
  • the power supply switching circuit 12B of FIG. 3 includes a Zener diode 22, a first diode 21, a resistor 20, an NMOS 23, a second diode 24, and a second capacitor 25.
  • the rise of the voltage of the second node 27 activates the NMOS 23, and the first node 26 is biased in accordance with the voltage between the gate and the source of the NMOS 23. Thus, the voltage is output to the first node 26 by the supply of the first power supply V1. At this time, the second diode 24 has a backflow prevention function.
  • the output terminal voltage V3 of the first node 26 is substantially independent of the first power supply V1, and is constant determined by the voltage Vz of the Zener diode 22, the voltage Vf1 of the first diode 21, the gate-to-source voltage Vgs of the NMOS 23.
  • the voltage V3A Vz + Vf1-Vgs.
  • the output terminal OUT is a constant voltage independent of the voltage of the first power supply V1.
  • V3A Vz + Vf1-Vgs (first voltage) is output from the first power supply V1 through the NMOS 23 (transistor).
  • the gate and source voltages of the NMOS 23 also have negative temperature characteristics, so that the temperature dependency is canceled out.
  • the voltage V3 can be output to the first node 26 with low temperature dependency by using the Zener diode 22 with low temperature dependency.
  • the voltage V3 is a voltage for driving the internal power supply circuit 13, and has to be higher than the output voltage of the internal power supply circuit 13. By the supply of the voltage V3, the internal power supply circuit 13 generates an output voltage V4.
  • the first node voltage V3B becomes a voltage V2-Vf2 and is supplied from the second power supply V2, and the power supply of V3 is switched from the first power supply V1 to the second power supply V2.
  • the output terminal OUT outputs the second voltage (V2-Vf2) from the second power supply V2 through the second diode 24 when the voltage of the second power supply V2 is higher than the predetermined voltage (Vz + Vf1-Vgs + Vf2).
  • the voltage V3A In order to switch to the second power supply V2, the voltage V3A needs to be set lower than the voltage V2-Vf2.
  • the power consumption of the internal power supply circuit 13 is current I3
  • the power consumption is switched from V1 ⁇ I3 at the time of supplying the first power supply V1 to V2 ⁇ I3 at the time of supplying the second power supply V2, and the second power supply V2 is By lowering it, the power consumption of the internal power supply circuit and the heat generation associated therewith can be reduced.
  • the power supply switching circuit according to the first embodiment of the present invention can switch the output voltage V3 from the first power supply V1 to the second power supply V2 when the voltage V2 becomes equal to or higher than a desired voltage.
  • the V2 voltage can be set to a voltage lower than the V1 voltage, it is possible to reduce the power consumption and heat generation of the internal power supply circuit 13 connected to V3.
  • the first power supply can be used to output a voltage independent of the voltage of the first power supply.
  • FIG. 4 is a circuit diagram of a power supply switching circuit 12C according to a second embodiment of the present invention.
  • a third diode 29 disposed between the first node 26 and the NMOS 23 is added. That is, the third diode 29 has an anode connected to the source of the NMOS 23 (transistor) and a cathode connected to the first node 26.
  • the voltage V2 becomes higher than the voltage V1
  • the V2 voltage for switching the power supply is a voltage which is V2 ⁇ Vf2> Vz + Vf1 ⁇ Vgs ⁇ Vf3.
  • the power supply switching circuit switches the output voltage V3 from the first power supply V1 to the second power supply V2 when the V2 voltage is equal to or higher than the desired voltage, as in the first embodiment. I can do it.
  • the V2 voltage is set to a voltage lower than the V1 voltage, it is possible to reduce the power consumption and heat generation of the internal power supply circuit 13 connected to V3.
  • the V2 voltage is higher than the V1 voltage, it is possible to prevent the current from flowing back to the first power supply V1.
  • FIG. 5 is a block diagram of an on-vehicle electronic control device 31 provided with a power supply IC 11 according to a third embodiment of the present invention.
  • the power supply IC 11 incorporates the power supply switching circuit 12 (or 12A to 12C), the internal power supply circuit 13, the step-down switching regulator 14, the series power supply 15, and the driver circuit 16.
  • the battery 10 is connected to the first power supply V1 of the power supply switching circuit 12, and the output voltage V5 obtained by smoothing the switching output of the step-down switching regulator 14 with the inductor 17 and the first capacitor 18 is used for the second power supply V2.
  • the first power source V1 is the battery 10 (battery power source)
  • the second power source V2 is the step-down switching regulator 14.
  • the internal power supply circuit 13 is connected to the output terminal voltage V3.
  • the output voltage V4 of the internal power supply circuit 13 is connected to the step-down switching regulator 14, each series power supply 15, and the driver circuit 16, and becomes a power supply voltage for driving each circuit.
  • the step-down switching regulator 14 is connected to the battery 10 and steps down from the battery 10 to generate a voltage V5 required for the series power supply 15.
  • the voltage V5 is a negative feedback voltage of the step-down switching regulator 14.
  • the series power supply 15 generates a plurality of power supply voltages V6 and V7 required for the microcomputer 30 and power supply voltages V8 for various sensors 34 for detecting information required for vehicle control, by stepping down from the V5 voltage.
  • the driver circuit 16 also drives a plurality of actuator loads 32 and 33 mounted on the vehicle.
  • the power supply switching circuit 12 raises the V2 voltage lower than the V1 voltage to a desired voltage or higher, whereby the V5 voltage is connected to the internal power supply circuit 13.
  • the power consumption P1 of the internal power supply circuit 13 driven with a lower V2 voltage is reduced to V5 ⁇ I3.
  • the current I3 of the internal power supply circuit 13 is newly supplied via V5, so the power consumption of the step-down switching regulator 14 is increased.
  • the efficiency of the step-down switching regulator 14 is K and the power consumption P1 of the internal power supply circuit 13
  • the battery 10 voltage is 14 V
  • the V5 voltage is 6 V
  • the conversion efficiency is 90%
  • the power supply IC 11 generates a plurality of power supplies for driving the microcomputer 30, and it is necessary to terminate the internal power supply circuit 13 after the plurality of power supplies have ended normally.
  • the internal power supply circuit 13 is stably driven from the voltage V0 by the operation of the power supply switching circuit 12, whereby the power supply IC11 is assured. It is possible to complete the termination sequence.
  • the internal power supply circuit 13 is stably driven from the V0 voltage by the operation of the power supply switching circuit 12.
  • the internal power supply circuit 13 is driven by the voltage V5, and power consumption is similarly reduced.
  • FIG. 6 is a time chart of the power supply IC according to the third embodiment.
  • t0 indicates the timing when the start signal is input.
  • the period from t0 to t1 is a startup period in which the internal power supply circuit 13, the step-down switching regulator 14 and each series power supply 15 mounted on the power supply IC 11 are activated.
  • the internal voltage V3A Vz + Vf1-Vgs of the power supply switching circuit 12 is supplied from the battery voltage V0.
  • the internal power supply circuit 13 starts the V4 voltage.
  • the step-down switching regulator 14 is activated and the output voltage V5 rises.
  • the power supply switching circuit 12 operates to supply power from V5 to the internal power supply circuit 13, and the power consumption of the power supply IC11 is reduced.
  • step-down switching regulator 14 is activated by voltage V4 (third voltage) supplied from internal power supply circuit 13. After that, the step-down switching regulator 14 supplies the output voltage V5 to the internal power supply circuit 13.
  • T1 to t2 indicate the normal operation period of the power supply IC 11.
  • the on-vehicle electronic control device including the microcomputer continues the normal operation, and the power consumption of the power supply IC 11 becomes the largest.
  • the voltage V5 is constantly output, and the power consumption of the internal power supply circuit 13 is reduced to about half, so that the power consumption of the power supply IC 11 is suppressed and the heat generation is also reduced.
  • T2 to t3 indicate the end period of the power supply IC 11.
  • the fall of the start signal shuts off the step-down switching regulator 14 and each series power supply 15, and finally, a termination sequence in which the internal power supply circuit is turned off is started.
  • the internal power supply circuit 13 switches to the drive from the battery power supply V0 by the operation of the power supply switching circuit 12 and continues the stable operation. It becomes possible. That is, when the voltage supplied from the step-down switching regulator 14 to the internal power supply circuit 13 is lower than the predetermined voltage (Vz + Vf1-Vgs + Vf2) in the end sequence, the power supply switching circuit 12 sets V3A (first voltage) to the battery 10 (battery power). ) Through the NMOS 23 (transistor).
  • the power supply IC 11 operates in the end period and the operation of the on-vehicle control device by the microcomputer is stopped. There is no influence on heat generation etc.
  • the power consumption of the internal power supply circuit 13 is not reduced, but the power consumption of the entire power supply IC is sufficiently small so that there is no influence on heat generation.
  • the internal power supply circuit 13 supplies the output voltage V4 to the step-down switching regulator 14.
  • the present invention is not limited to the above-described embodiment, but includes various modifications.
  • the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.
  • part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
  • step-down switching regulator 14 is provided inside the power supply IC 11 in the above embodiment, it may be provided outside the power supply IC 11.
  • NMOS 23 is used as the transistor in the above embodiment, an NPN bipolar transistor may be used.
  • the embodiment of the present invention may have the following aspects.
  • a diode for temperature characteristic correction, a zener diode for generating a reference voltage, and a reference voltage generated by the zener voltage and the forward voltage of the diode is connected to the gate of the NMOS transistor.
  • An on-vehicle electronic control device including the power supply switching circuit according to any one of (1) to (5), wherein the power supply switching circuit is mounted on a power supply IC.
  • the internal voltage is driven using a battery voltage at the time of start-up, and the step-down switching regulator is activated after the step-down switching regulator is activated.
  • a power supply IC for applying the voltage of (1) to the internal power supply.
  • the power supply to the internal power supply circuit can be stably switched with small voltage fluctuation.
  • the power consumption of the internal power supply circuit can be reduced and the heat generation of the IC can be reduced by switching between the battery voltage and the step-down switching regulator output voltage.
  • it is possible to select a low cost package with relatively large thermal resistance by reducing the heat generation of the IC simplify the heat dissipation structure of the chassis of the on-vehicle control device to finally dissipate the heat generation of the IC, and reduce the cost of heat dissipation material. And the cost reduction of the on-vehicle control device.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
  • Continuous-Control Power Sources That Use Transistors (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

The present invention provides a power supply switching circuit or the like which is capable of outputting a voltage independent of a voltage of a first power supply by using the first power supply while switching the first power supply and a second power supply according to a voltage of the second power supply. An output terminal OUT is connected to a first node 26 connecting a current path connected to a first power supply V1 and a current path connected to a second power supply V2 for supplying a voltage lower than that of the first power supply V1. A resistor 20 is connected to the first power supply V1. A Zener diode 22 is connected in series to the resistor 20. An NMOS 23 (transistor) has a gate (control electrode) connected to a second node 27 connecting the resistor 20 and the Zener diode 22, and turns on/off a current path between the first power supply V1 and the output terminal OUT in accordance with a voltage applied to the gate. A second diode 24 rectifies a current flowing through a current path between the second power supply V2 and the output terminal OUT.

Description

電源切り替え回路、電源ＩＣ及び車載電子制御装置Power supply switching circuit, power supply IC and in-vehicle electronic control device
　本発明は、電源切り替え回路、電源ＩＣ及び車載電子制御装置に関する。 The present invention relates to a power supply switching circuit, a power supply IC, and an on-vehicle electronic control device.
　電子制御装置に搭載される半導体集積回路IC（Integrated Circuit）は高機能化、高集積化が進んでおり、それに伴い消費電力が増大し、損失、発熱が増大している。半導体の発熱が増大すると、その熱を放熱するために高価な低熱抵抗のパッケージが必要となったり、また半導体が実装される基板や筐体の放熱構造や放熱材料の高コスト化を招いたりという課題が発生する。これら放熱対策のためのコストを最小限にするため、半導体の消費電力、発熱の低減が求められている。 A semiconductor integrated circuit IC (Integrated Circuit) mounted on an electronic control device is advanced in function and integration, and power consumption is increased accordingly, and loss and heat generation are increased. If the heat generation of the semiconductor increases, an expensive low thermal resistance package is required to dissipate the heat, or the heat dissipation structure of the substrate or housing on which the semiconductor is mounted or the cost increase of the heat dissipation material may be caused. An issue arises. In order to minimize the cost for these heat dissipation measures, it is required to reduce the power consumption and heat generation of the semiconductor.
　車載電子制御装置においても、搭載されるマイクロコンピュータ（マイコン）やICなどの半導体は高機能化、高集積化が進んでおり消費電力も増大している。その中で、マイコンの電源を生成する電源ICやアクチュエータ負荷を駆動するためのドライバICには、大電流駆動のための大きな消費電力が求められる。 Also in the on-vehicle electronic control device, semiconductors such as microcomputers (microcomputers) and ICs mounted therein are becoming highly functional and highly integrated, and power consumption is also increasing. Among them, a large power consumption for driving a large current is required for a power supply IC for generating a power supply of a microcomputer and a driver IC for driving an actuator load.
　これらICの消費電力は、マイコンの電源生成やアクチュエータ駆動のための駆動電流による消費電力と、DCDC電源やドライバ回路を駆動、信号処理するための内部電源回路の消費電力に大別できる。 The power consumption of these ICs can be roughly divided into power consumption by drive current for microcomputer power generation and actuator drive, and power consumption of an internal power supply circuit for driving and signal processing DCDC power supply and driver circuits.
　従来この内部電源回路の消費電力は、IC全体の消費電力に対して割合が小さかったため、内部電源回路の消費電力の削減効果は小さかった。しかし、ICの高機能化、高集積化が進むにつれて、この内部電源回路の消費電力、発熱の割合は増加し、影響が大きくなっている。 Conventionally, the power consumption of the internal power supply circuit was small in proportion to the power consumption of the entire IC, so the reduction effect of the power consumption of the internal power supply circuit was small. However, the power consumption and heat generation ratio of the internal power supply circuit are increasing and the influence is increasing as the function and integration of ICs are advanced.
　車載電子制御装置では、供給される主な電源としてバッテリがあり、このバッテリ電圧を直接、もしくは降圧、昇圧して制御に必要な所望の電圧を生成している。内部電源回路の消費電力を下げるためには、一般的に印加される電圧か消費する電流を下げることが考えられ、消費電流を一定とすると駆動する電圧を下げることで、消費電力を下げることが可能となる。 In the on-vehicle electronic control device, there is a battery as a main power source to be supplied, and this battery voltage is directly or step down and boosted to generate a desired voltage required for control. In order to reduce the power consumption of the internal power supply circuit, it is generally considered to lower the applied voltage or the consumed current, and if the current consumption is constant, the power consumption can be reduced by lowering the driving voltage. It becomes possible.
　ここで、電源ICの内部電源回路の機能は、IC内部の基準電圧、基準クロックの生成、各DCDC電源、各ドライバ回路の駆動、マイコンとの通信機能等である。そのため、バッテリ電圧からDCDC電源によって降圧した電圧で内部回路を駆動する場合は、まずはバッテリで内部電源回路を駆動する。その後、DCDC電源によって降圧した電圧を内部電源回路に供給する必要があり、バッテリ電圧と降圧した電圧を切り替える回路が必要となる。 Here, the function of the internal power supply circuit of the power supply IC is a reference voltage in the IC, generation of a reference clock, DCDC power supplies, driving of each driver circuit, communication function with a microcomputer, and the like. Therefore, when the internal circuit is driven with a voltage stepped down from the battery voltage by the DCDC power supply, the internal power supply circuit is first driven by the battery. After that, it is necessary to supply a voltage stepped down by the DCDC power supply to the internal power supply circuit, and a circuit to switch the battery voltage and the stepped-down voltage is needed.
　半導体集積回路において、複数の電圧を選択するための電源切り替え技術が知られている。例えば、特許文献１に記載の技術は、Ｆｌｅｘ Ｒａｙ規格のトランシーバＩＣに適用した場合、低消費電力モードであっても余剰な回路電流を必要とせず適切に動作することが出来る。 In semiconductor integrated circuits, power supply switching techniques for selecting a plurality of voltages are known. For example, when the technology described in Patent Document 1 is applied to a transceiver IC of the Flex Ray standard, even in the low power consumption mode, it can operate properly without requiring extra circuit current.
　図７は、特許文献１に記載の電源切り替え回路の構成図である。Ｆｌｅｘ Ｒａｙ規格のトランシーバＩＣに適用した場合、Ｖ１０２がバッテリ電圧ＶＢＡＴ、Ｖ１０１がＶＣＣ電源電圧に相当する。ＶＣＣ電源電圧が所定の電圧よりも低いときはＰＭＯＳ１０５を活性化することにより、Ｖ１０２から電源が供給される。 FIG. 7 is a block diagram of the power supply switching circuit described in Patent Document 1. As shown in FIG. When applied to a FlexRay transceiver IC, V102 corresponds to the battery voltage VBAT, and V101 corresponds to the VCC power supply voltage. When the VCC power supply voltage is lower than a predetermined voltage, power is supplied from V 102 by activating the PMOS 105.
　図７の電源回路は、ＰＭＯＳ１０５を活性化させることにより、低消費電力モードであってもトランシーバＩＣに流れる電流以外の電流は流れず、適切に動作する電源切り替え回路を実現している。 By activating the PMOS 105, the power supply circuit of FIG. 7 realizes a power supply switching circuit that operates properly, with no current other than the current flowing through the transceiver IC flowing even in the low power consumption mode.
特開2012-222844号公報JP 2012-222844 A
　電子制御装置に搭載される半導体集積回路の内部電源回路で発生する消費電力、またそれに伴う発熱を低減するため、内部電源回路に接続される電圧をより低電圧で駆動するように切り替える必要がある。 It is necessary to switch the voltage connected to the internal power supply circuit to be driven with a lower voltage in order to reduce the power consumption generated in the internal power supply circuit of the semiconductor integrated circuit mounted on the electronic control unit and the heat generation associated therewith. .
　上述の特許文献１に記載された切り替え回路の出力電圧は、Ｖ１０１とＶ１０２からそれぞれダイオードの順方向電圧だけ低下した電圧となる。すなわち、この出力電圧は、Ｖ１０１とＶ１０２の電圧に依存し、その電圧差が大きいと切り替わる出力電圧も大きく変動することになる。 The output voltage of the switching circuit described in Patent Document 1 described above is a voltage obtained by reducing the forward voltage of each of the diodes from V101 and V102. That is, this output voltage depends on the voltages of V101 and V102, and when the voltage difference is large, the output voltage to be switched also largely fluctuates.
　特許文献１に記載された切り替え回路を半導体集積回路の内部電源回路への接続に適用し、バッテリ電圧とＤＣＤＣ電源電圧とを切り替えて駆動すると、切り替わる出力電圧がバッテリ電圧とＤＣＤＣ電源電圧に依存して大きく変動してしまう。 When the switching circuit described in Patent Document 1 is applied to the connection to the internal power supply circuit of the semiconductor integrated circuit and the battery voltage and the DCDC power supply voltage are switched and driven, the switching output voltage depends on the battery voltage and the DCDC power supply voltage. It will fluctuate greatly.
　また、Ｖ１０１が急に電源低下した場合は、抵抗列１１６やＰＭＯＳ１０５のゲート容量などで発生する時定数により、ＰＭＯＳ１０５の活性化が遅れ、切り替わりの瞬間に出力電圧の低下が発生することが考えられる。 In addition, when V 101 suddenly drops in power, activation of PMOS 105 is delayed due to a time constant generated by the gate capacitance of resistor string 116 or PMOS 105, and a drop in output voltage may occur at the moment of switching. .
　集積回路の内部電源回路は、基準電圧や基準クロックを常時安定して生成する必要がある。しかし、切り替わりにより、電圧が大きく変動したり、瞬間的な電圧の低下が発生したりすると、基準電圧や基準クロックの変動、または内部電源回路出力が低下するなど、切り替り時の安定動作に課題がある。 The internal power supply circuit of the integrated circuit needs to constantly generate a reference voltage and a reference clock stably. However, if switching causes a large voltage fluctuation or a momentary voltage drop, the reference voltage or reference clock fluctuation, or the output of the internal power supply circuit decreases, which causes a problem in stable operation at switching. There is.
　本発明の目的は、第２電源の電圧に応じて第１電源と第２電源を切り替えつつ、第１電源を用いて第１電源の電圧に依存しない電圧を出力することができる電源切り替え回路等を提供することにある。 The object of the present invention is to switch the first power supply and the second power supply according to the voltage of the second power supply and to output a voltage independent of the voltage of the first power supply using the first power supply, etc. To provide.
　上記目的を達成するために、本発明は、第１電源に接続される電流経路と前記第１電源より低い電圧を供給する第２電源に接続される電流経路とを接続する第１ノードに接続される出力端子と、前記第１電源に接続される抵抗と、前記抵抗に直列に接続されるツェナーダイオードと、前記抵抗と前記ツェナーダイオードとを接続する第２ノードに接続される制御電極を有し、前記制御電極に印加される電圧に応じて、前記第１電源と前記出力端子の間の電流経路をオン／オフするトランジスタと、前記第２電源と前記出力端子の間の電流経路を流れる電流を整流する第２ダイオードと、を備える。 In order to achieve the above object, the present invention is connected to a first node connecting a current path connected to a first power supply and a current path connected to a second power supply supplying a voltage lower than the first power supply. Output terminal, a resistor connected to the first power supply, a Zener diode connected in series to the resistor, and a control electrode connected to a second node connecting the resistor and the Zener diode. A transistor that turns on / off a current path between the first power supply and the output terminal according to a voltage applied to the control electrode, and flows through the current path between the second power supply and the output terminal And a second diode that rectifies the current.
　本発明によれば、第２電源の電圧に応じて第１電源と第２電源を切り替えつつ、第１電源を用いて第１電源の電圧に依存しない電圧を出力することができる。上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。 According to the present invention, it is possible to output a voltage independent of the voltage of the first power supply using the first power supply while switching the first power supply and the second power supply according to the voltage of the second power supply. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.
本発明の実施形態１に係る電源切り替え回路図である。It is a power supply switching circuit diagram concerning Embodiment 1 of the present invention. 本発明の実施形態１の変形例１に係る電源切り替え回路図である。It is a power supply switching circuit diagram which concerns on the modification 1 of Embodiment 1 of this invention. 本発明の実施形態１の変形例２に係る電源切り替え回路図である。It is a power supply switching circuit diagram which concerns on the modification 2 of Embodiment 1 of this invention. 本発明の実施形態２に係る電源切り替え回路図である。It is a power supply switching circuit diagram which concerns on Embodiment 2 of this invention. 本発明の実施形態３に係る電源ＩＣの構成図である。It is a block diagram of power supply IC which concerns on Embodiment 3 of this invention. 本発明の実施形態３に係る電源ＩＣのタイムチャートである。It is a time chart of power supply IC concerning Embodiment 3 of the present invention. 特許文献１に記載の電源切り替え回路の構成を示す回路図である。FIG. 6 is a circuit diagram showing a configuration of a power supply switching circuit described in Patent Document 1.
　以下、添付図面を参照して、本発明の実施形態１～３に係る電源切り替え回路、電源ＩＣ、及び車載電子制御装置の構成を詳細に説明する。なお、各図において、同一符号は同一部分を示す。本実施形態では、電源の切り替え時に、内部電源回路を継続して安定動作させ、電源の切り替えにより内部電源回路の消費電力を低減することを目的とする。 Hereinafter, configurations of a power supply switching circuit, a power supply IC, and an on-vehicle electronic control device according to Embodiments 1 to 3 of the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals indicate the same parts. An object of the present embodiment is to continuously operate the internal power supply circuit stably at the time of switching the power supply and to reduce the power consumption of the internal power supply circuit by switching the power supply.
　（実施形態１）
　図１は、本発明の実施形態１に係る電源切り替え回路１２の回路図である。 (Embodiment 1)
FIG. 1 is a circuit diagram of a power supply switching circuit 12 according to a first embodiment of the present invention.
　図１の電源切り替え回路１２は、ツェナーダイオード２２、抵抗２０、ＮＭＯＳ２３（N-channel Metal Oxide Semiconductor）、および第２ダイオード２４で構成される。 The power supply switching circuit 12 of FIG. 1 includes a Zener diode 22, a resistor 20, an NMOS 23 (N-channel Metal Oxide Semiconductor), and a second diode 24.
　ここで、出力端子ＯＵＴは、第１電源Ｖ１に接続される電流経路と第１電源Ｖ１より低い電圧を供給する第２電源Ｖ２に接続される電流経路とを接続する第１ノード２６に接続される。抵抗２０は、第１電源Ｖ１に接続される。ツェナーダイオード２２は、抵抗２０に直列に接続される。ＮＭＯＳ２３（トランジスタ）は、抵抗２０とツェナーダイオード２２とを接続する第２ノード２７に接続されるゲート（制御電極）を有し、ゲートに印加される電圧に応じて、第１電源Ｖ１と出力端子ＯＵＴの間の電流経路をオン／オフする。第２ダイオード２４は、第２電源Ｖ２と出力端子ＯＵＴの間の電流経路を流れる電流を整流する。 Here, the output terminal OUT is connected to a first node 26 connecting a current path connected to the first power supply V1 and a current path connected to the second power supply V2 supplying a voltage lower than that of the first power supply V1. Ru. The resistor 20 is connected to the first power supply V1. The zener diode 22 is connected in series to the resistor 20. The NMOS 23 (transistor) has a gate (control electrode) connected to the second node 27 connecting the resistor 20 and the Zener diode 22, and according to the voltage applied to the gate, the first power supply V1 and the output terminal Turn on / off the current path between OUT. The second diode 24 rectifies the current flowing in the current path between the second power supply V2 and the output terminal OUT.
　まず、第１電源Ｖ１が供給されると、抵抗２０を介して、ツェナーダイオード２２に電流が供給され、第２ノード２７の電圧は、ツェナーダイオード２２の電圧と第２ダイオードの電圧とでバイアスされる。 First, when the first power supply V1 is supplied, a current is supplied to the zener diode 22 through the resistor 20, and the voltage of the second node 27 is biased by the voltage of the zener diode 22 and the voltage of the second diode. Ru.
　第２ノード２７の電圧の上昇によって、ＮＭＯＳ２３が活性化し、ＮＭＯＳ２３のゲート、ソース間電圧に応じて第１ノード２６がバイアスされる。このように、第１電源Ｖ１の供給により、第１ノード２６に電圧が出力される。このとき、第２ダイオード２４は逆流防止の機能となっている。 The rise of the voltage of the second node 27 activates the NMOS 23, and the first node 26 is biased in accordance with the voltage between the gate and the source of the NMOS 23. Thus, the voltage is output to the first node 26 by the supply of the first power supply V1. At this time, the second diode 24 has a backflow prevention function.
　ここで、第１ノード２６の出力端子電圧Ｖ３は、第１電源Ｖ１にほとんど依存せず、ツェナーダイオード２２の電圧Ｖｚ、ＮＭＯＳ２３のゲート、ソース間電圧Ｖｇｓで決まる一定電圧Ｖ３Ａ０＝Ｖｚ－Ｖｇｓとなる。 Here, the output terminal voltage V3 of the first node 26 is substantially independent of the first power supply V1 and is a constant voltage V3A0 = Vz-Vgs determined by the voltage Vz of the Zener diode 22, the gate-to-source voltage Vgs of the NMOS 23. .
　この電圧Ｖ３は、内部電源回路１３を駆動するための電圧であり、内部電源回路１３の出力電圧よりも高い電圧である必要がある。電圧Ｖ３の供給により、内部電源回路１３は出力電圧Ｖ４を生成する。 The voltage V3 is a voltage for driving the internal power supply circuit 13, and has to be higher than the output voltage of the internal power supply circuit 13. By the supply of the voltage V3, the internal power supply circuit 13 generates an output voltage V4.
　ここで、第２電源Ｖ２が供給された場合、第２電源Ｖ２が第１電源Ｖ１から供給された電圧Ｖ３Ａ０＝Ｖｚ－Ｖｇｓよりさらに第２ダイオード２４の電圧Ｖｆ２以上となったとき、第２電源Ｖ２から第１ノード２６へ電流が流れる。 Here, when the second power supply V2 is supplied, when the voltage Vf2 of the second diode 24 is more than the voltage V3A0 = Vz−Vgs supplied from the first power supply V1, the second power supply A current flows from V2 to the first node 26.
　そのとき、第１ノード電圧Ｖ３Ｂは、Ｖ２－Ｖｆ２電圧となり第２電源Ｖ２から供給され、Ｖ３の供給電源が第１電源Ｖ１から第２電源Ｖ２に切り替る。 At that time, the first node voltage V3B becomes a voltage V2-Vf2 and is supplied from the second power supply V2, and the power supply of V3 is switched from the first power supply V1 to the second power supply V2.
　第２電源Ｖ２への切り替りのため、Ｖ３Ａ０の電圧は、Ｖ２－Ｖｆ２電圧よりも低く設定する必要がある。 In order to switch to the second power supply V2, the voltage V3A0 needs to be set lower than the voltage V2-Vf2.
　内部電源回路１３の消費電流を電流Ｉ３とすると、この電源切り替わりにより、消費電力は、第１電源Ｖ１供給時のＶ１×Ｉ３から第２電源Ｖ２供給時のＶ２×Ｉ３となり、第２電源Ｖ２を下げることで内部電源回路の消費電力、およびそれに伴う発熱を低減することが出来る。 Assuming that the consumption current of the internal power supply circuit 13 is current I3, the power consumption is switched from V1 × I3 at the time of supplying the first power supply V1 to V2 × I3 at the time of supplying the second power supply V2, and the second power supply V2 is By lowering it, the power consumption of the internal power supply circuit and the heat generation associated therewith can be reduced.
　次に、第２電源Ｖ２が低下したときは、Ｖ１からＶ２への切り替りと同様に、Ｖ２－Ｖｆ２電圧がＶ３Ａ０電圧よりも低くなったとき、ＮＭＯＳ２３のゲート、ソース間電圧Ｖｇｓが十分に開くことで、ＮＭＯＳ２３が活性化し、第１電源Ｖ１から電流が供給され電源電圧が切り替る。 Next, when the second power supply V2 drops, as in the case of switching from V1 to V2, when the V2-Vf2 voltage becomes lower than the V3A0 voltage, the gate-source voltage Vgs of the NMOS 23 sufficiently opens Thus, the NMOS 23 is activated, current is supplied from the first power supply V1, and the power supply voltage is switched.
　（変形例１）
　図２は、本発明の実施形態１の変形例１に係る電源切り替え回路１２Ａの回路図である。図１に示す電源切り替え回路１２に、第１ノード２６と内部電源回路１３の間に配置される第２コンデンサ２５を追加した構成である。すなわち、出力端子ＯＵＴに第２コンデンサ２５の一端が接続される。 (Modification 1)
FIG. 2 is a circuit diagram of a power supply switching circuit 12A according to a first modification of the first embodiment of the present invention. The power supply switching circuit 12 shown in FIG. 1 has a configuration in which a second capacitor 25 disposed between the first node 26 and the internal power supply circuit 13 is added. That is, one end of the second capacitor 25 is connected to the output terminal OUT.
　Ｖ２からＶ１への切り替り時、Ｖ２が急峻に低下した場合を考慮すると、ＮＭＯＳ２３からの電流供給が遅くなり、瞬間的にＶ３の電圧が低下することが考えられる。そのため、第２コンデンサ２５を接続し、急峻な切り替り時は第２コンデンサ２５から電流を供給することで、内部電源回路の安定動作が維持される。 When switching from V2 to V1, considering that V2 drops sharply, it is conceivable that the current supply from the NMOS 23 is delayed and the voltage of V3 drops instantaneously. Therefore, the stable operation of the internal power supply circuit is maintained by connecting the second capacitor 25 and supplying a current from the second capacitor 25 at the time of abrupt switching.
　（変形例２）
　図３は、本発明の実施形態１の変形例２に係る電源切り替え回路１２Ｂの回路図である。図２に示す電源切り替え回路１２Ａに、第２ノード２７とツェナーダイオード２２の間に配置される第１ダイオード２１を追加した構成である。すなわち、第１ダイオード２１は、第２ノード２７に接続されるアノード、及びツェナーダイオード２２のカソードに接続されるカソードを有する。第１ダイオード２１によりＮＭＯＳ２３（トランジスタ）の電圧の負の温度特性がキャンセルされる。 (Modification 2)
FIG. 3 is a circuit diagram of a power supply switching circuit 12B according to a second modification of the first embodiment of the present invention. The configuration is such that the first diode 21 disposed between the second node 27 and the Zener diode 22 is added to the power supply switching circuit 12A shown in FIG. That is, the first diode 21 has an anode connected to the second node 27 and a cathode connected to the cathode of the zener diode 22. The first diode 21 cancels the negative temperature characteristic of the voltage of the NMOS 23 (transistor).
　詳細には、図３の電源切り替え回路１２Ｂは、ツェナーダイオード２２、第１ダイオード２１、抵抗２０、ＮＭＯＳ２３、第２ダイオード２４、および第２コンデンサ２５で構成される。 In detail, the power supply switching circuit 12B of FIG. 3 includes a Zener diode 22, a first diode 21, a resistor 20, an NMOS 23, a second diode 24, and a second capacitor 25.
　まず、第１電源Ｖ１が供給されると、抵抗２０を介して、第１ダイオード２１、ツェナーダイオード２２に電流が供給され、第２ノード２７の電圧は、ツェナーダイオード２２の電圧と第２ダイオードの電圧とでバイアスされる。 First, when the first power supply V1 is supplied, current is supplied to the first diode 21 and the zener diode 22 through the resistor 20, and the voltage of the second node 27 becomes the voltage of the zener diode 22 and the voltage of the second diode. Biased with voltage.
　第２ノード２７の電圧の上昇によって、ＮＭＯＳ２３が活性化し、ＮＭＯＳ２３のゲート、ソース間電圧に応じて第１ノード２６がバイアスされる。このように、第１電源Ｖ１の供給により、第１ノード２６に電圧が出力される。このとき、第２ダイオード２４は逆流防止の機能となっている。 The rise of the voltage of the second node 27 activates the NMOS 23, and the first node 26 is biased in accordance with the voltage between the gate and the source of the NMOS 23. Thus, the voltage is output to the first node 26 by the supply of the first power supply V1. At this time, the second diode 24 has a backflow prevention function.
　ここで、第１ノード２６の出力端子電圧Ｖ３は、第１電源Ｖ１にほとんど依存せず、ツェナーダイオード２２の電圧Ｖｚ、第１ダイオード２１の電圧Ｖｆ１、ＮＭＯＳ２３のゲート、ソース間電圧Ｖｇｓで決まる一定電圧Ｖ３Ａ＝Ｖｚ＋Ｖｆ１－Ｖｇｓとなる。 Here, the output terminal voltage V3 of the first node 26 is substantially independent of the first power supply V1, and is constant determined by the voltage Vz of the Zener diode 22, the voltage Vf1 of the first diode 21, the gate-to-source voltage Vgs of the NMOS 23. The voltage V3A = Vz + Vf1-Vgs.
　すなわち、ツェナーダイオード２２と第１ダイオード２１によって生成される基準電圧がＮＭＯＳ２３（トランジスタ）のゲート（制御電極）に印加されることにより、出力端子ＯＵＴは、第１電源Ｖ１の電圧に依存しない一定電圧Ｖ３Ａ＝Ｖｚ＋Ｖｆ１－Ｖｇｓ（第１電圧）を第１電源Ｖ１からＮＭＯＳ２３（トランジスタ）を介して出力する。 That is, by applying the reference voltage generated by the Zener diode 22 and the first diode 21 to the gate (control electrode) of the NMOS 23 (transistor), the output terminal OUT is a constant voltage independent of the voltage of the first power supply V1. V3A = Vz + Vf1-Vgs (first voltage) is output from the first power supply V1 through the NMOS 23 (transistor).
　温度特性についても、第１ダイオード２１が負の温度特性を持つが、ＮＭＯＳ２３のゲート、ソース電圧も負の温度特性であるため温度依存性を打ち消し合う。温度依存性の小さいツェナーダイオード２２を使用することで、温度依存性の小さい第１ノード２６に電圧Ｖ３を出力することが出来る。 As for the temperature characteristics, although the first diode 21 has negative temperature characteristics, the gate and source voltages of the NMOS 23 also have negative temperature characteristics, so that the temperature dependency is canceled out. The voltage V3 can be output to the first node 26 with low temperature dependency by using the Zener diode 22 with low temperature dependency.
　この電圧Ｖ３は、内部電源回路１３を駆動するための電圧であり、内部電源回路１３の出力電圧よりも高い電圧である必要がある。電圧Ｖ３の供給により、内部電源回路１３は出力電圧Ｖ４を生成する。 The voltage V3 is a voltage for driving the internal power supply circuit 13, and has to be higher than the output voltage of the internal power supply circuit 13. By the supply of the voltage V3, the internal power supply circuit 13 generates an output voltage V4.
　ここで、第２電源Ｖ２が供給された場合、第２電源Ｖ２が第１電源Ｖ１から供給された電圧Ｖ３Ａ＝Ｖｚ＋Ｖｆ１－Ｖｇｓよりさらに第２ダイオード２４の電圧Ｖｆ２以上となったとき、第２電源Ｖ２から第１ノード２６へ電流が流れる。 Here, when the second power supply V2 is supplied, when the voltage Vf2 of the second diode 24 is more than the voltage V3A = Vz + Vf1-Vgs supplied from the first power supply V1, the second power supply A current flows from V2 to the first node 26.
　そのとき、第１ノード電圧Ｖ３Ｂは、Ｖ２－Ｖｆ２電圧となり第２電源Ｖ２から供給され、Ｖ３の供給電源が第１電源Ｖ１から第２電源Ｖ２に切り替る。 At that time, the first node voltage V3B becomes a voltage V2-Vf2 and is supplied from the second power supply V2, and the power supply of V3 is switched from the first power supply V1 to the second power supply V2.
　すなわち、出力端子ＯＵＴは、第２電源Ｖ２の電圧が所定電圧（Ｖｚ＋Ｖｆ１－Ｖｇｓ＋Ｖｆ２）より高い場合、第２電圧（Ｖ２－Ｖｆ２）を第２電源Ｖ２から第２ダイオード２４を介して出力する。 That is, the output terminal OUT outputs the second voltage (V2-Vf2) from the second power supply V2 through the second diode 24 when the voltage of the second power supply V2 is higher than the predetermined voltage (Vz + Vf1-Vgs + Vf2).
　第２電源Ｖ２への切り替りのため、Ｖ３Ａの電圧は、Ｖ２－Ｖｆ２電圧よりも低く設定する必要がある。 In order to switch to the second power supply V2, the voltage V3A needs to be set lower than the voltage V2-Vf2.
　内部電源回路１３の消費電流を電流Ｉ３とすると、この電源切り替わりにより、消費電力は、第１電源Ｖ１供給時のＶ１×Ｉ３から第２電源Ｖ２供給時のＶ２×Ｉ３となり、第２電源Ｖ２を下げることで内部電源回路の消費電力、およびそれに伴う発熱を低減することが出来る。 Assuming that the consumption current of the internal power supply circuit 13 is current I3, the power consumption is switched from V1 × I3 at the time of supplying the first power supply V1 to V2 × I3 at the time of supplying the second power supply V2, and the second power supply V2 is By lowering it, the power consumption of the internal power supply circuit and the heat generation associated therewith can be reduced.
　次に、第２電源Ｖ２が低下したときは、Ｖ１からＶ２への切り替りと同様に、Ｖ２－Ｖｆ２電圧がＶ３Ａ電圧よりも低くなったとき、ＮＭＯＳ２３のゲート、ソース間電圧Ｖｇｓが十分に開くことで、ＮＭＯＳ２３が活性化し、第１電源Ｖ１から電流が供給され電源電圧が切り替る。 Next, when the second power supply V2 falls, as in the case of switching from V1 to V2, when the V2-Vf2 voltage becomes lower than the V3A voltage, the voltage Vgs between the gate and the source of the NMOS 23 sufficiently opens Thus, the NMOS 23 is activated, current is supplied from the first power supply V1, and the power supply voltage is switched.
　すなわち、出力端子ＯＵＴは、第２電源Ｖ２の電圧が所定電圧（Ｖｚ＋Ｖｆ１－Ｖｇｓ＋Ｖｆ２）より低い場合、一定電圧Ｖ３Ａ＝Ｖｚ＋Ｖｆ１－Ｖｇｓ（第１電圧）を第１電源Ｖ１からＮＭＯＳ２３（トランジスタ）を介して出力する。 That is, when the voltage of the second power supply V2 is lower than the predetermined voltage (Vz + Vf1-Vgs + Vf2), the output terminal OUT performs constant voltage V3A = Vz + Vf1-Vgs (first voltage) from the first power supply V1 through the NMOS 23 (transistor). Output.
　（実施形態１のまとめ）
　以上のように、本発明の実施形態１に係る電源切り替え回路は、Ｖ２電圧が所望の電圧以上となると、出力電圧Ｖ３を第１電源Ｖ１から第２電源Ｖ２に切り替えることが出来る。これにより、Ｖ２電圧をＶ１電圧より低電圧と設定することで、Ｖ３に接続される内部電源回路１３の消費電力、発熱を低減することが出来る。また、第２電源の電圧に応じて第１電源と第２電源を切り替えつつ、第１電源を用いて第１電源の電圧に依存しない電圧を出力することができる。 (Summary of Embodiment 1)
As described above, the power supply switching circuit according to the first embodiment of the present invention can switch the output voltage V3 from the first power supply V1 to the second power supply V2 when the voltage V2 becomes equal to or higher than a desired voltage. Thus, by setting the V2 voltage to a voltage lower than the V1 voltage, it is possible to reduce the power consumption and heat generation of the internal power supply circuit 13 connected to V3. In addition, while switching between the first power supply and the second power supply according to the voltage of the second power supply, the first power supply can be used to output a voltage independent of the voltage of the first power supply.
　（実施形態２）
　図４は、本発明の実施形態２に係る電源切り替え回路１２Ｃの回路図である。電源切り替え回路１２に、第１ノード２６とＮＭＯＳ２３の間に配置される第３ダイオード２９を追加した構成である。すなわち、第３ダイオード２９は、ＮＭＯＳ２３（トランジスタ）のソースに接続されるアノード、及び第１ノード２６に接続されるカソードを有する。これにより、Ｖ２電圧がＶ１電圧よりも高くなっても、第１電源Ｖ１への電流の逆流を防ぐことが出来る。 Second Embodiment
FIG. 4 is a circuit diagram of a power supply switching circuit 12C according to a second embodiment of the present invention. In the power supply switching circuit 12, a third diode 29 disposed between the first node 26 and the NMOS 23 is added. That is, the third diode 29 has an anode connected to the source of the NMOS 23 (transistor) and a cathode connected to the first node 26. Thereby, even if the voltage V2 becomes higher than the voltage V1, it is possible to prevent the backflow of the current to the first power supply V1.
　しかし、実施形態１の構成と比較して、低電圧での下限の動作電圧範囲が第３ダイオードの順方向電圧のＶｆ３だけ高くなるという点がある。 However, in comparison with the configuration of the first embodiment, there is a point that the lower limit operating voltage range at low voltage is higher by Vf3 of the forward voltage of the third diode.
　電源が切り替るためのＶ２電圧は、Ｖ２－Ｖｆ２＞Ｖｚ＋Ｖｆ１－Ｖｇｓ－Ｖｆ３となる電圧である。 The V2 voltage for switching the power supply is a voltage which is V2−Vf2> Vz + Vf1−Vgs−Vf3.
　（実施形態２のまとめ）
　以上のように、本発明の実施形態２に係る電源切り替え回路は、実施形態１と同様に、Ｖ２電圧が所望の電圧以上となると、出力電圧Ｖ３を第１電源Ｖ１から第２電源Ｖ２に切り替えることが出来る。これにより、Ｖ２電圧をＶ１電圧より低電圧と設定することで、Ｖ３に接続される内部電源回路１３の消費電力、発熱を低減することが出来る。また、Ｖ２電圧がＶ１電圧よりも高くなる場合があっても、第１電源Ｖ１への電流が逆流することを防止できる。 (Summary of Embodiment 2)
As described above, the power supply switching circuit according to the second embodiment of the present invention switches the output voltage V3 from the first power supply V1 to the second power supply V2 when the V2 voltage is equal to or higher than the desired voltage, as in the first embodiment. I can do it. Thus, by setting the V2 voltage to a voltage lower than the V1 voltage, it is possible to reduce the power consumption and heat generation of the internal power supply circuit 13 connected to V3. In addition, even if the V2 voltage is higher than the V1 voltage, it is possible to prevent the current from flowing back to the first power supply V1.
　（実施形態３）
　図５は、本発明の実施形態３に係る電源ＩＣ１１を備えた車載電子制御装置３１の構成図である。電源ＩＣ１１は、電源切り替え回路１２（又は１２Ａ～１２Ｃ）、内部電源回路１３、降圧スイッチングレギュレータ１４、シリーズ電源１５、ドライバ回路１６を内蔵する。 (Embodiment 3)
FIG. 5 is a block diagram of an on-vehicle electronic control device 31 provided with a power supply IC 11 according to a third embodiment of the present invention. The power supply IC 11 incorporates the power supply switching circuit 12 (or 12A to 12C), the internal power supply circuit 13, the step-down switching regulator 14, the series power supply 15, and the driver circuit 16.
　この電源ＩＣ１１では、電源切り替え回路１２の第１電源Ｖ１にはバッテリ１０が接続され、第２電源Ｖ２には降圧スイッチングレギュレータ１４のスイッチング出力をインダクタ１７と第１コンデンサ１８で平滑した出力電圧Ｖ５が接続される。すなわち、第１電源Ｖ１は、バッテリ１０（バッテリ電源）であり、第２電源Ｖ２は、降圧スイッチングレギュレータ１４である。また、出力端子電圧Ｖ３には内部電源回路１３が接続される。 In this power supply IC 11, the battery 10 is connected to the first power supply V1 of the power supply switching circuit 12, and the output voltage V5 obtained by smoothing the switching output of the step-down switching regulator 14 with the inductor 17 and the first capacitor 18 is used for the second power supply V2. Connected That is, the first power source V1 is the battery 10 (battery power source), and the second power source V2 is the step-down switching regulator 14. Further, the internal power supply circuit 13 is connected to the output terminal voltage V3.
　内部電源回路１３の出力電圧Ｖ４は、降圧スイッチングレギュレータ１４、各シリーズ電源１５、ドライバ回路１６に接続され、各回路を駆動するための電源電圧となる。降圧スイッチングレギュレータ１４は、バッテリ１０に接続され、バッテリ１０から降圧してシリーズ電源１５に必要な電圧Ｖ５を生成する。また電圧Ｖ５は降圧スイッチングレギュレータ１４の負帰還電圧となっている。 The output voltage V4 of the internal power supply circuit 13 is connected to the step-down switching regulator 14, each series power supply 15, and the driver circuit 16, and becomes a power supply voltage for driving each circuit. The step-down switching regulator 14 is connected to the battery 10 and steps down from the battery 10 to generate a voltage V5 required for the series power supply 15. The voltage V5 is a negative feedback voltage of the step-down switching regulator 14.
　次にシリーズ電源１５により、マイコン３０に必要な複数の電源電圧Ｖ６、Ｖ７や車両制御に必要な情報を検出するための各種センサ３４用の電源電圧Ｖ８がＶ５電圧から降圧されて生成される。また、ドライバ回路１６により、車両に搭載された複数のアクチュエータ負荷３２、３３が駆動される。 Next, the series power supply 15 generates a plurality of power supply voltages V6 and V7 required for the microcomputer 30 and power supply voltages V8 for various sensors 34 for detecting information required for vehicle control, by stepping down from the V5 voltage. The driver circuit 16 also drives a plurality of actuator loads 32 and 33 mounted on the vehicle.
　まず、内部電源回路１３に流れるＶ３の消費電流をＩ３とすると、電源切り替え回路１２のＶ１電圧から電源が供給されている場合、バッテリ１０からの消費電力Ｐ０はＶ０×Ｉ３となる。 First, assuming that the consumption current of V3 flowing to the internal power supply circuit 13 is I3, when power is supplied from the V1 voltage of the power supply switching circuit 12, the power consumption P0 from the battery 10 is V0 × I3.
　次に、電源切り替え回路１２によって、Ｖ１電圧より低いＶ２電圧が所望の電圧以上に上昇することで、内部電源回路１３にＶ５電圧が接続される。これにより、実施形態１での説明のように、より低いＶ２電圧で駆動される内部電源回路１３の消費電力Ｐ１はＶ５×Ｉ３と低減される。 Next, the power supply switching circuit 12 raises the V2 voltage lower than the V1 voltage to a desired voltage or higher, whereby the V5 voltage is connected to the internal power supply circuit 13. As a result, as described in the first embodiment, the power consumption P1 of the internal power supply circuit 13 driven with a lower V2 voltage is reduced to V5 × I3.
　ここで、電源ＩＣ１１の消費電力を考えると、内部電源回路１３の電流Ｉ３が新たにＶ５を介して供給されるため、降圧スイッチングレギュレータ１４の消費電力は増加することになる。 Here, considering the power consumption of the power supply IC 11, the current I3 of the internal power supply circuit 13 is newly supplied via V5, so the power consumption of the step-down switching regulator 14 is increased.
　降圧スイッチングレギュレータ１４の効率をＫ、内部電源回路１３の消費電力Ｐ１とすると、バッテリ１０から消費される電力Ｐ０’は、Ｐ１/Ｐ０’＝Ｋの関係で電力変換される。すなわち、バッテリ１０から流れる電流をＩ０’とすると、（Ｖ５×Ｉ３）/（Ｖ０×Ｉ０’）＝Ｋとなる。 Assuming that the efficiency of the step-down switching regulator 14 is K and the power consumption P1 of the internal power supply circuit 13, the power P0 'consumed from the battery 10 is power converted in the relationship of P1 / P0' = K. That is, assuming that the current flowing from the battery 10 is I 0 ′, (V 5 × I 3) / (V 0 × I 0 ′) = K.
　ここで、バッテリ１０電圧を１４Ｖ、Ｖ５電圧を６Ｖ、変換効率を９０％とすると、Ｉ０’＝Ｖ５/Ｖ０×Ｉ３×１/Ｋ＝Ｉ３×０．４７６となり、電源切り替え後の電源ＩＣの消費電力Ｐ０’＝Ｖ０×Ｉ０’＝ Ｖ０×Ｉ３×０．４７６＝Ｐ０×０．４７６となる。すなわち、電源切り替えにより、内部電源回路１３の消費電力をおよそ半分に低減することが出来る。 Here, assuming that the battery 10 voltage is 14 V, the V5 voltage is 6 V, and the conversion efficiency is 90%, I0 ′ = V5 / V0 × I3 × 1 / K = I3 × 0.476, and consumption of the power supply IC after power supply switching Power P0 ′ = V0 × I0 ′ = V0 × I3 × 0.476 = P0 × 0.476. That is, the power consumption of the internal power supply circuit 13 can be reduced to about half by switching the power supply.
　降圧スイッチングレギュレータ１４の代わりにバッテリ１０からシリーズ電源でＶ５電圧を生成した場合、内部電源回路１３で消費される電流Ｉ３は、結局、バッテリ１０から同じ電流が流れることになり、電源ＩＣ１１としての消費電力は電源切り替え回路１２のＶ１を介した場合と変わらないため、消費電力の削減効果はない。そのため、第２電源を内蔵する電源ＩＣ１１に電源切り替え回路１２を適用するには、電力変換ロスの少ない降圧スイッチングレギュレータ１４の構成が必要となる。 When the V5 voltage is generated by the series power supply from the battery 10 instead of the step-down switching regulator 14, the current I3 consumed by the internal power supply circuit 13 eventually flows from the battery 10, and consumption as the power supply IC11 Since the power is the same as when V1 of the power supply switching circuit 12 is used, there is no reduction effect of power consumption. Therefore, in order to apply the power supply switching circuit 12 to the power supply IC 11 incorporating the second power supply, the configuration of the step-down switching regulator 14 with little power conversion loss is required.
　つぎに、電源ＩＣ１１の電源終了時の動作を説明する。電源ＩＣ１１はマイコン３０を駆動する複数の電源を生成しており、複数の電源が正常に終了した後に、内部電源回路１３を終了する必要がある。 Next, the operation at the time of the end of the power supply IC 11 will be described. The power supply IC 11 generates a plurality of power supplies for driving the microcomputer 30, and it is necessary to terminate the internal power supply circuit 13 after the plurality of power supplies have ended normally.
　すなわち、終了シーケンスの中で、Ｖ５電圧が所望の電圧よりも低下したときに、電源切り替え回路１２の動作により、Ｖ０電圧から内部電源回路１３が安定的に駆動されることにより、電源ＩＣ１１は確実に終了シーケンスを完了することが可能となる。 That is, when the voltage V5 falls below the desired voltage in the termination sequence, the internal power supply circuit 13 is stably driven from the voltage V0 by the operation of the power supply switching circuit 12, whereby the power supply IC11 is assured. It is possible to complete the termination sequence.
　また、通常動作時にも、何らかの要因で意図せずＶ５電圧が低下した際も、電源切り替え回路１２の動作により、Ｖ０電圧から内部電源回路１３が安定的に駆動される。またＶ５電圧が正常電圧に回復した際は、Ｖ５電圧で内部電源回路１３が駆動され、同様に消費電力が削減される。 In addition, also in the normal operation, even when the V5 voltage drops unintentionally due to some cause, the internal power supply circuit 13 is stably driven from the V0 voltage by the operation of the power supply switching circuit 12. When the voltage V5 is restored to the normal voltage, the internal power supply circuit 13 is driven by the voltage V5, and power consumption is similarly reduced.
　図６は実施形態３に係る電源ＩＣのタイムチャートである。ｔ０は、起動信号が入力されたタイミングを示す。ｔ０からｔ１までは、電源ＩＣ１１に搭載される内部電源回路１３、降圧スイッチングレギュレータ１４および各シリーズ電源１５が起動する起動期間である。 FIG. 6 is a time chart of the power supply IC according to the third embodiment. t0 indicates the timing when the start signal is input. The period from t0 to t1 is a startup period in which the internal power supply circuit 13, the step-down switching regulator 14 and each series power supply 15 mounted on the power supply IC 11 are activated.
　この起動期間において、まず電源切り替え回路１２の内部電圧Ｖ３Ａ＝Ｖｚ＋Ｖｆ1－Ｖｇｓがバッテリ電圧Ｖ０から供給される。Ｖ３が供給されることによって、内部電源回路１３がＶ４電圧を起動する。内部電源回路１３の起動により、内部基準電圧、内部クロックの生成が完了すると、降圧スイッチングレギュレータ１４が起動し、出力電圧Ｖ５が立上る。 In this start-up period, first, the internal voltage V3A = Vz + Vf1-Vgs of the power supply switching circuit 12 is supplied from the battery voltage V0. By supplying V3, the internal power supply circuit 13 starts the V4 voltage. When the generation of the internal reference voltage and the internal clock is completed by activation of the internal power supply circuit 13, the step-down switching regulator 14 is activated and the output voltage V5 rises.
　ここで、Ｖ５電圧が所望の電圧Ｖｚ＋Ｖｆ1－Ｖｇｓ＋Ｖｆ2を超えると、電源切り替え回路１２の動作により、Ｖ５から内部電源回路１３への電源が供給され、電源ＩＣ１１の消費電力が低減される。この時、Ｖ３電圧はＶ３Ｂ＝Ｖ５－Ｖｆ２となる。 Here, when the V5 voltage exceeds the desired voltage Vz + Vf1-Vgs + Vf2, the power supply switching circuit 12 operates to supply power from V5 to the internal power supply circuit 13, and the power consumption of the power supply IC11 is reduced. At this time, the V3 voltage is V3B = V5-Vf2.
　すなわち、起動シーケンスにおいて、一定電圧Ｖ３Ａ＝Ｖｚ＋Ｖｆ１－Ｖｇｓ（第１電圧）により内部電源回路１３が起動し、内部電源回路１３から供給されるＶ４電圧（第３電圧）により降圧スイッチングレギュレータ１４が起動した後、降圧スイッチングレギュレータ１４は内部電源回路１３へ出力電圧Ｖ５を供給する。 That is, in the start-up sequence, internal power supply circuit 13 is activated by constant voltage V3A = Vz + Vf1-Vgs (first voltage), and step-down switching regulator 14 is activated by voltage V4 (third voltage) supplied from internal power supply circuit 13. After that, the step-down switching regulator 14 supplies the output voltage V5 to the internal power supply circuit 13.
　ｔ１からｔ２は、電源ＩＣ１１の通常動作期間を示す。この期間では、マイコンを含めた車載電子制御装置が通常動作を継続し、電源ＩＣ１１の消費電力は最も大きくなる。その期間で常時Ｖ５電圧が出力され、内部電源回路１３の消費電力がおよそ半分に削減されることで、電源ＩＣ１１の消費電力は抑えられ、その発熱も低減される効果がある。 T1 to t2 indicate the normal operation period of the power supply IC 11. During this period, the on-vehicle electronic control device including the microcomputer continues the normal operation, and the power consumption of the power supply IC 11 becomes the largest. During this period, the voltage V5 is constantly output, and the power consumption of the internal power supply circuit 13 is reduced to about half, so that the power consumption of the power supply IC 11 is suppressed and the heat generation is also reduced.
　ｔ２からｔ３は、電源ＩＣ１１の終了期間を示す。起動信号の立下りにより、降圧スイッチングレギュレータ１４、各シリーズ電源１５がシャットオフし、最後に内部電源回路がオフする終了シーケンスが開始される。 T2 to t3 indicate the end period of the power supply IC 11. The fall of the start signal shuts off the step-down switching regulator 14 and each series power supply 15, and finally, a termination sequence in which the internal power supply circuit is turned off is started.
　電源ＩＣ１１の終了期間中に、Ｖ５電圧が所望の電圧Ｖｚ＋Ｖｆ1－Ｖｇｓ＋Ｖｆ2よりも下がると、電源切り替え回路１２の動作により、内部電源回路１３はバッテリ電源Ｖ０からの駆動に切り替り、安定動作を継続することが可能となる。すなわち、終了シーケンスにおいて、降圧スイッチングレギュレータ１４から内部電源回路１３へ供給される電圧が所定電圧（Ｖｚ＋Ｖｆ１－Ｖｇｓ＋Ｖｆ２）より低い場合、電源切り替え回路１２は、Ｖ３Ａ（第１電圧）をバッテリ１０（バッテリ電源）からＮＭＯＳ２３（トランジスタ）を介して出力する。 If the voltage V5 falls below the desired voltage Vz + Vf1-Vgs + Vf2 during the end of the power supply IC 11, the internal power supply circuit 13 switches to the drive from the battery power supply V0 by the operation of the power supply switching circuit 12 and continues the stable operation. It becomes possible. That is, when the voltage supplied from the step-down switching regulator 14 to the internal power supply circuit 13 is lower than the predetermined voltage (Vz + Vf1-Vgs + Vf2) in the end sequence, the power supply switching circuit 12 sets V3A (first voltage) to the battery 10 (battery power). ) Through the NMOS 23 (transistor).
　この時、内部電源回路１３の消費電力の低減効果はなくなるが、電源ＩＣ１１は終了期間の動作となっており、マイコンによる車載制御装置の動作は停止しているため電源ＩＣ１１全体の消費電力は十分に低いため発熱などへの影響はない。 At this time, although the reduction effect of the power consumption of the internal power supply circuit 13 disappears, the power supply IC 11 operates in the end period and the operation of the on-vehicle control device by the microcomputer is stopped. There is no influence on heat generation etc.
　同様に、電源ＩＣ１１の起動期間中も、内部電源回路１３の消費電力は低減されないが電源ＩＣ全体の消費電力は十分小さいため発熱などへの影響はない。 Similarly, even during the start-up period of the power supply IC 11, the power consumption of the internal power supply circuit 13 is not reduced, but the power consumption of the entire power supply IC is sufficiently small so that there is no influence on heat generation.
　ここで、内部電源回路１３は、入力電圧であるＶ３Ａ＝Ｖｚ＋Ｖｆ１－Ｖｇｓ（第１電圧）又はＶ３Ｂ＝Ｖ５－Ｖｆ２（第２電圧）から一定の出力電圧Ｖ４（第３電圧）を生成する。内部電源回路１３は、出力電圧Ｖ４を降圧スイッチングレギュレータ１４へ供給する。 Here, the internal power supply circuit 13 generates a constant output voltage V4 (third voltage) from the input voltage V3A = Vz + Vf1-Vgs (first voltage) or V3B = V5-Vf2 (second voltage). The internal power supply circuit 13 supplies the output voltage V4 to the step-down switching regulator 14.
　（実施形態３のまとめ）
　以上のように、電源ＩＣ１１に電源切り替え回路１２を適用すると、降圧スイッチングレギュレータ出力電圧Ｖ５が所望の電圧以上となることで、内部電源回路１３の電源がバッテリ１０の電圧Ｖ０から降圧スイッチングレギュレータ出力電圧Ｖ５に切り替り、内部電源回路１３の消費電力を低減することが出来る。また、電源ＩＣの起動期間や、終了期間において、Ｖ５電圧の変化に伴い内部電源回路１３の電源が切り替った際も、内部電源回路１３が動作を安定して継続できる。 (Summary of Embodiment 3)
As described above, when the power supply switching circuit 12 is applied to the power supply IC 11, the step-down switching regulator output voltage V5 becomes equal to or higher than a desired voltage. By switching to V5, power consumption of the internal power supply circuit 13 can be reduced. Further, even when the power supply of the internal power supply circuit 13 is switched due to the change of the voltage V5 in the start-up period and the end period of the power supply IC, the internal power supply circuit 13 can continue its operation stably.
　なお、本発明は上記した実施形態に限定されるものではなく、様々な変形例が含まれる。例えば、上述した実施形態は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、また、ある実施形態の構成に他の実施形態の構成を加えることも可能である。また、各実施形態の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 The present invention is not limited to the above-described embodiment, but includes various modifications. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Further, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, and replace other configurations for part of the configurations of the respective embodiments.
　上記実施形態では、降圧スイッチングレギュレータ１４は、電源ＩＣ１１の内部に設けられるが、電源ＩＣ１１の外部に設けられてもよい。 Although the step-down switching regulator 14 is provided inside the power supply IC 11 in the above embodiment, it may be provided outside the power supply IC 11.
　上記実施形態では、トランジスタとしてＮＭＯＳ２３を用いているが、ＮＰＮバイポーラトランジスタを用いてもよい。 Although the NMOS 23 is used as the transistor in the above embodiment, an NPN bipolar transistor may be used.
　なお、本発明の実施形態は、以下の態様であってもよい。 The embodiment of the present invention may have the following aspects.
　（１）．第１電源からＮＭＯＳトランジスタを介して供給される電流経路と、第２電源から整流用ダイオードを介して供給される電流経路が接続される出力端子を具備し、第１電源には、電流制限用の抵抗と、温度特性補正用のダイオード、基準電圧生成用のツェナーダイオードが接続され、ツェナー電圧とダイオードの順方向電圧によって生成された基準電圧がＮＭＯＳトランジスタのゲートに接続されることによって、第１電源電圧に依存しない電圧を第１電源から出力端子に供給し、第２電源電圧が第１電源から出力端子に供給された所望の電圧よりも高いときに、第２電源から出力端子に電流が供給されることを特徴とする電源切り替え回路。 (1). A current path supplied from a first power supply via an NMOS transistor, and an output terminal to which a current path supplied from a second power supply via a rectifying diode is connected, and the first power supply is for current limitation A diode for temperature characteristic correction, a zener diode for generating a reference voltage, and a reference voltage generated by the zener voltage and the forward voltage of the diode is connected to the gate of the NMOS transistor. When a voltage independent of the power supply voltage is supplied from the first power supply to the output terminal and the second power supply voltage is higher than the desired voltage supplied from the first power supply to the output terminal, a current flows from the second power supply to the output terminal A power supply switching circuit characterized by being supplied.
　（２）．（１）に記載の電源切り替え回路において、前記第２電源電圧が第１電源から出力端子に供給された所望の電圧よりも低いときに、前記第１電源からＮＭＯＳトランジスタを介して第１電源電圧に依存しない電圧を出力端子に供給することを特徴とする電源切り替え回路。 (2). In the power supply switching circuit according to (1), when the second power supply voltage is lower than a desired voltage supplied from the first power supply to the output terminal, the first power supply voltage from the first power supply via the NMOS transistor A power supply switching circuit characterized by supplying a voltage independent of the output terminal.
　（３）．（１）又は（２）に記載の電源切り替え回路において、前記第１電源は、バッテリ電源であり、前記第２電源は、降圧スイッチングレギュレータを特徴とする電源切り替え回路。 (3). The power supply switching circuit according to (1) or (2), wherein the first power supply is a battery power supply, and the second power supply is a step-down switching regulator.
　（４）．（１）から（３）のいずれかに記載の電源切り替え回路において、前記出力端子は、ＩＣ内の内部電源回路に接続される特徴とする電源切り替え回路。 (4). The power supply switching circuit according to any one of (1) to (3), wherein the output terminal is connected to an internal power supply circuit in an IC.
　（５）．（１）から（４）のいずれかに記載の電源切り替え回路において、前記第１電源に逆流防止用のダイオードを設けたことを特徴とする電源切り替え回路。 (5). The power supply switching circuit according to any one of (1) to (4), wherein a diode for backflow prevention is provided in the first power supply.
　（６）．（１）から（５）のいずれかに記載の電源切り替え回路を含む車載電子制御装置において、前記電源切り替え回路は、電源ＩＣに搭載されることを特徴とする車載電子制御装置。 (6). An on-vehicle electronic control device including the power supply switching circuit according to any one of (1) to (5), wherein the power supply switching circuit is mounted on a power supply IC.
　（７）．（１）から（５）のいずれかに記載の電源切り替え回路を含む車載電子制御装置において、起動時にはバッテリ電圧を用いて内部電源を駆動し、前記降圧スイッチングレギュレータが起動した後に、前記降圧スイッチングレギュレータの電圧を前記内部電源に印加する電源ＩＣを備えることを特徴とする車載電子制御装置。 (7). In the on-vehicle electronic control device including the power supply switching circuit according to any one of (1) to (5), the internal voltage is driven using a battery voltage at the time of start-up, and the step-down switching regulator is activated after the step-down switching regulator is activated. And a power supply IC for applying the voltage of (1) to the internal power supply.
　（８）．（１）から（５）のいずれかに記載の電源切り替え回路を含む車載電子制御装置において、停止時には、前記内部電源を駆動していた前記降圧スイッチングレギュレータの電圧が所定の電圧以下となった場合に、前記バッテリ電圧に切り替る前記電源ＩＣを備えることを特徴とする車載電子制御装置。 (8). In the on-vehicle electronic control device including the power supply switching circuit according to any one of (1) to (5), when the voltage of the step-down switching regulator driving the internal power supply becomes lower than a predetermined voltage An on-vehicle electronic control device including the power supply IC switching to the battery voltage.
　（１）～（８）によれば、電圧変動を小さく、安定的に内部電源回路への電源を切り替えることが出来る。車載電子制御装置に適用する場合、バッテリ電圧と降圧スイッチングレギュレータ出力電圧との切り替えにより、内部電源回路の消費電力を低減し、ＩＣの発熱を低減することが出来る。また、ＩＣの発熱低減により比較的熱抵抗の大きな低コストパッケージを選択でき、ＩＣの発熱を最終的に放熱するための車載制御装置の筐体の放熱構造の簡素化、放熱材料の低コスト化につながるなど、車載制御装置の低コスト化となる効果がある。 According to (1) to (8), the power supply to the internal power supply circuit can be stably switched with small voltage fluctuation. When applied to an on-vehicle electronic control device, the power consumption of the internal power supply circuit can be reduced and the heat generation of the IC can be reduced by switching between the battery voltage and the step-down switching regulator output voltage. In addition, it is possible to select a low cost package with relatively large thermal resistance by reducing the heat generation of the IC, simplify the heat dissipation structure of the chassis of the on-vehicle control device to finally dissipate the heat generation of the IC, and reduce the cost of heat dissipation material. And the cost reduction of the on-vehicle control device.
１０…バッテリ
１１…電源IC
１２、１２Ａ、１２Ｂ…電源切り替え回路
１３…内部電源回路
１４…降圧スイッチングレギュレータ
１５…シリーズ電源（外部駆動電源）
１６…ドライバ回路
１７…インダクタ
１８…第１コンデンサ
２０…抵抗
２１…第１ダイオード
２２…ツェナーダイオード
２３…ＮＭＯＳ
２４…第２ダイオード
２５…第２コンデンサ
２６…第１ノード
２７…第２ノード
２８…Ｉ３電流
２９…第３ダイオード
３０…マイコン
３１…車載電子制御装置
３２、３３…アクチュエータ負荷
３４…センサ 10: Battery 11: Power supply IC
12, 12A, 12B: power supply switching circuit 13: internal power supply circuit 14: step-down switching regulator 15: series power supply (external drive power supply)
DESCRIPTION OF SYMBOLS 16 ... Driver circuit 17 ... Inductor 18 ... 1st capacitor | condenser 20 ... Resistance 21 ... 1st diode 22 ... Zener diode 23 ... NMOS
24 ... second diode 25 ... second capacitor 26 ... first node 27 ... second node 28 ... I3 current 29 ... third diode 30 ... microcomputer 31 ... in-vehicle electronic control device 32, 33 ... actuator load 34 ... sensor

Claims (12)

  1. 　第１電源に接続される電流経路と前記第１電源より低い電圧を供給する第２電源に接続される電流経路とを接続する第１ノードに接続される出力端子と、
    　前記第１電源に接続される抵抗と、
    　前記抵抗に直列に接続されるツェナーダイオードと、
    　前記抵抗と前記ツェナーダイオードとを接続する第２ノードに接続される制御電極を有し、前記制御電極に印加される電圧に応じて、前記第１電源と前記出力端子の間の電流経路をオン／オフするトランジスタと、
    　前記第２電源と前記出力端子の間の電流経路を流れる電流を整流する第２ダイオードと、
    　を備えることを特徴とする電源切り替え回路。     An output terminal connected to a first node connecting a current path connected to a first power supply and a current path connected to a second power supply supplying a voltage lower than the first power supply;
    A resistor connected to the first power supply;
    A zener diode connected in series with the resistor;
    A control electrode connected to a second node connecting the resistor and the Zener diode, and turning on a current path between the first power supply and the output terminal according to a voltage applied to the control electrode Transistors that turn off
    A second diode that rectifies a current flowing in a current path between the second power supply and the output terminal;
    A power supply switching circuit comprising:
  2. 　請求項１に記載の電源切り替え回路であって、
    　前記出力端子に一端が接続されるコンデンサをさらに備える
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 1, wherein
    The power supply switching circuit, further comprising: a capacitor whose one end is connected to the output terminal.
  3. 　請求項２に記載の電源切り替え回路であって、
    　前記第２ノードに接続されるアノード、及び前記ツェナーダイオードのカソードに接続されるカソードを有する第１ダイオードをさらに備える
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 2, wherein
    The power supply switching circuit, further comprising: a first diode having an anode connected to the second node and a cathode connected to a cathode of the zener diode.
  4. 　請求項３に記載の電源切り替え回路であって、
    　前記トランジスタに接続されるアノード、及び前記第１ノードに接続されるカソードを有する第３ダイオードをさらに備える
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 3, wherein
    The power supply switching circuit, further comprising: a third diode having an anode connected to the transistor and a cathode connected to the first node.
  5. 　請求項３に記載の電源切り替え回路であって、
    　前記出力端子は、
    　前記ツェナーダイオードと前記第１ダイオードによって生成される基準電圧が前記トランジスタの制御電極に印加されることにより、前記第１電源の電圧に依存しない第１電圧を前記第１電源から前記トランジスタを介して出力し、
    　前記第２電源の電圧が所定電圧より高い場合、第２電圧を前記第２電源から前記第２ダイオードを介して出力する
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 3, wherein
    The output terminal is
    A reference voltage generated by the zener diode and the first diode is applied to the control electrode of the transistor, whereby a first voltage independent of the voltage of the first power source is transmitted from the first power source to the transistor. Output
    When the voltage of the second power supply is higher than a predetermined voltage, a second voltage is output from the second power supply via the second diode.
  6. 　請求項５に記載の電源切り替え回路であって、
    　前記出力端子は、
    　前記第２電源の電圧が前記所定電圧より低い場合、前記第１電圧を前記第１電源から前記トランジスタを介して出力する
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 5, wherein
    The output terminal is
    The power supply switching circuit, wherein the first voltage is outputted from the first power supply via the transistor when the voltage of the second power supply is lower than the predetermined voltage.
  7. 　請求項５に記載の電源切り替え回路であって、
    　前記第１電源は、
    　バッテリ電源であり、
    　前記第２電源は、
    　降圧スイッチングレギュレータである
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 5, wherein
    The first power supply is
    Battery power,
    The second power source is
    It is a step-down switching regulator.
  8. 　請求項３に記載の電源切り替え回路であって、
    　前記第１ダイオードは、
    　前記トランジスタの電圧の負の温度特性をキャンセルする
    　ことを特徴とする電源切り替え回路。     The power supply switching circuit according to claim 3, wherein
    The first diode is
    A power supply switching circuit that cancels the negative temperature characteristic of the voltage of the transistor.
  9. 　請求項７に記載の電源切り替え回路を含む電源ＩＣであって、
    　前記降圧スイッチングレギュレータと、
    　前記第１電圧又は前記第２電圧から第３電圧を生成する内部電源回路と、をさらに備え、
    　前記内部電源回路は、
    　前記第３電圧を前記降圧スイッチングレギュレータへ供給する
    　ことを特徴とする電源ＩＣ。     A power supply IC including the power supply switching circuit according to claim 7, wherein
    The step-down switching regulator;
    An internal power supply circuit generating a third voltage from the first voltage or the second voltage;
    The internal power supply circuit is
    A power supply IC characterized in that the third voltage is supplied to the step-down switching regulator.
  10. 　請求項９に記載の電源切り替え回路を含む電源ＩＣであって、
    　起動シーケンスにおいて、前記第１電圧により前記内部電源回路が起動し、前記内部電源回路から供給される前記第３電圧により前記降圧スイッチングレギュレータが起動した後、前記降圧スイッチングレギュレータは前記内部電源回路へ電圧を供給する
    　ことを特徴とする電源ＩＣ。     A power supply IC including the power supply switching circuit according to claim 9,
    In the start-up sequence, after the internal power supply circuit is activated by the first voltage and the step-down switching regulator is activated by the third voltage supplied from the internal power supply circuit, the step-down switching regulator supplies a voltage to the internal power supply circuit. Power supply IC characterized by supplying
  11. 　請求項９に記載の電源切り替え回路を含む電源ＩＣであって、
    　終了シーケンスにおいて、前記電源切り替え回路は、前記降圧スイッチングレギュレータから前記内部電源回路へ供給される電圧が前記所定電圧より低い場合、前記第１電圧を前記バッテリ電源から前記トランジスタを介して出力する
    　ことを特徴とする電源ＩＣ。     A power supply IC including the power supply switching circuit according to claim 9,
    In the termination sequence, when the voltage supplied from the step-down switching regulator to the internal power supply circuit is lower than the predetermined voltage, the power supply switching circuit outputs the first voltage from the battery power supply via the transistor. Power supply IC featuring.
  12. 　請求項７に記載の電源切り替え回路を含む車載電子制御装置であって、
    　前記降圧スイッチングレギュレータと、
    　前記第１電圧又は前記第２電圧から第３電圧を生成する内部電源回路と、をさらに備え、
    　前記内部電源回路は、
    　前記第３電圧を前記降圧スイッチングレギュレータへ供給する
    　ことを特徴とする車載電子制御装置。     An on-vehicle electronic control device including the power supply switching circuit according to claim 7;
    The step-down switching regulator;
    An internal power supply circuit generating a third voltage from the first voltage or the second voltage;
    The internal power supply circuit is
    An on-vehicle electronic control device, comprising: supplying the third voltage to the step-down switching regulator.
PCT/JP2018/038250 2017-10-30 2018-10-15 Power supply switching circuit, power supply ic and in-vehicle electronic control device WO2019087746A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012016152A (en) * 2010-06-30 2012-01-19 Standard Electric Co Ltd Ac motor and power supply
JP2013030091A (en) * 2011-07-29 2013-02-07 Mitsubishi Electric Corp Semiconductor device
JP2014023272A (en) * 2012-07-18 2014-02-03 Denso Corp Switching power-supply circuit
JP2014039465A (en) * 2012-08-17 2014-02-27 Lite On Technology Corp Apparatus and method for driving relay

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012016152A (en) * 2010-06-30 2012-01-19 Standard Electric Co Ltd Ac motor and power supply
JP2013030091A (en) * 2011-07-29 2013-02-07 Mitsubishi Electric Corp Semiconductor device
JP2014023272A (en) * 2012-07-18 2014-02-03 Denso Corp Switching power-supply circuit
JP2014039465A (en) * 2012-08-17 2014-02-27 Lite On Technology Corp Apparatus and method for driving relay

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