JP2014091495A - Short-cut detection circuit - Google Patents
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本発明は、バッテリ電源等により駆動される電動装置の負荷回路の短絡を検知する短絡検知回路に関する。 The present invention relates to a short circuit detection circuit that detects a short circuit of a load circuit of an electric device driven by a battery power source or the like.
電動リフト等、バッテリ電源で駆動される電動装置は、負荷回路の短絡を検知する短絡検知回路を備えている。図３は、従来の短絡検知回路の一例を示している。図３に示すように、負荷回路３−３は、主電源３−１の給電端子に第１のスイッチ３−２を介して一端が接続され、他端がメインスイッチ３−４を介して接地端子３−５に接続される。 An electric device driven by a battery power source such as an electric lift includes a short circuit detection circuit that detects a short circuit of a load circuit. FIG. 3 shows an example of a conventional short-circuit detection circuit. As shown in FIG. 3, the load circuit 3-3 has one end connected to the power supply terminal of the main power source 3-1 via the first switch 3-2 and the other end grounded via the main switch 3-4. Connected to terminal 3-5.
負荷回路３−３は、所定の抵抗値を有し、所定の電流消費量を消費し、また、動作中の抵抗値又は電流消費量を、制御用電子制御ユニット（ＥＣＵ）３−６の制御部３−７へ、図示省略の電子制御ユニット（ＥＣＵ）の通信部により通知する。制御用電子制御ユニット（ＥＣＵ）３−６の制御部３−７は、負荷回路３−３側から通知される抵抗値又は電流消費量を基に、負荷回路３−３の状態が正常か否か、即ち、短絡状態か否かを判断することができる。 The load circuit 3-3 has a predetermined resistance value, consumes a predetermined current consumption, and controls the resistance value or the current consumption during operation by the control electronic control unit (ECU) 3-6. This is notified to the unit 3-7 by a communication unit of an electronic control unit (ECU) (not shown). The control unit 3-7 of the control electronic control unit (ECU) 3-6 determines whether the state of the load circuit 3-3 is normal based on the resistance value or the current consumption amount notified from the load circuit 3-3 side. That is, it is possible to determine whether or not it is in a short-circuit state.
しかし、負荷回路３−３のメインスイッチ３−４が投入される前は、負荷回路３−３内の電子制御ユニット（ＥＣＵ）が起動しないため、メインスイッチ３−４が投入される前に、負荷回路３−３が短絡状態であるか否かを判断することはできない。 However, before the main switch 3-4 of the load circuit 3-3 is turned on, the electronic control unit (ECU) in the load circuit 3-3 does not start, so before the main switch 3-4 is turned on, It cannot be determined whether or not the load circuit 3-3 is in a short circuit state.
そこで、メインスイッチ３−４と並列に、短絡検知用の抵抗３−９と第２のスイッチ３−１０との直列回路を接続し、該短絡検知用の抵抗３−９の両端電圧又は該抵抗３−９に流れる電流を検出する電圧／電流測定部３−８を設ける。 Therefore, a series circuit of a short-circuit detection resistor 3-9 and a second switch 3-10 is connected in parallel with the main switch 3-4, and the voltage across the short-circuit detection resistor 3-9 or the resistor is connected. A voltage / current measurement unit 3-8 for detecting a current flowing through 3-9 is provided.
そして、メインスイッチ３−４を投入する前に、第１及び第２のスイッチ３−２，３−１０を導通させ、主電源３−１から負荷回路３−３に短絡検知用の抵抗３−９を通して電流を流し、電圧／電流測定部３−８により短絡検知用の抵抗３−９の両端の電圧、又は短絡検知用の抵抗３−９に流れる電流を測定する。 Before the main switch 3-4 is turned on, the first and second switches 3-2 and 3-10 are turned on, and the main power supply 3-1 connects the load circuit 3-3 with a short circuit detection resistor 3- 9, a current is passed through 9, and the voltage at both ends of the short-circuit detection resistor 3-9 or the current flowing through the short-circuit detection resistor 3-9 is measured by the voltage / current measurement unit 3-8.
電圧／電流測定部３−８は、この測定した電圧又は電流の値を、制御用電子制御ユニット（ＥＣＵ）３−６の制御部３−７に通知し、制御部３−７は、この通知された電圧又は電流の値を基に、負荷回路３−３が短絡状態か否かを判断する。 The voltage / current measurement unit 3-8 notifies the measured voltage or current value to the control unit 3-7 of the control electronic control unit (ECU) 3-6, and the control unit 3-7 notifies this notification. Whether or not the load circuit 3-3 is in a short-circuit state is determined based on the value of the voltage or current that has been set.
従来の短絡検知回路の他の一例を図４に示す。図４に示す回路例は、主電源電圧Ｂを供給する第１の電源と負荷回路Ｌ１との間に介在するスイッチング素子ＴＲ１のオン／オフにより、負荷回路Ｌ１及びスイッチング素子ＴＲ１の異常を検出する故障検出回路であり、下記の特許文献１に開示されている。なおダイオードＤ１は、負荷回路Ｌ１のサージ電流を吸収するためのものである。 Another example of a conventional short circuit detection circuit is shown in FIG. The circuit example shown in FIG. 4 detects an abnormality in the load circuit L1 and the switching element TR1 by turning on / off the switching element TR1 interposed between the first power supply that supplies the main power supply voltage B and the load circuit L1. This is a failure detection circuit, which is disclosed in Patent Document 1 below. The diode D1 is for absorbing the surge current of the load circuit L1.
図４に示す故障検出回路は、スイッチング素子ＴＲ１と負荷回路Ｌ１との接続点ａに、主電源電圧Ｂと異なる電圧Ｖｃｃを、ダイオードＤ２と抵抗Ｒ２との直列回路を介して印加し、負荷回路Ｌ１の短絡又は断線、及びスイッチング素子ＴＲ１の短絡故障又は開放故障を検出する。なお、ダイオードＤ２は、スイッチング素子ＴＲ１がオン状態のときに、第１の電源（主電源電圧Ｂ）から、第２の電源（電圧Ｖｃｃ）への電流の流れ込みを防止するためのものである。 The failure detection circuit shown in FIG. 4 applies a voltage Vcc different from the main power supply voltage B to a connection point a between the switching element TR1 and the load circuit L1 via a series circuit of a diode D2 and a resistor R2. L1 short circuit or disconnection, and switching element TR1 short circuit failure or open circuit failure are detected. The diode D2 is for preventing current from flowing from the first power supply (main power supply voltage B) to the second power supply (voltage Vcc) when the switching element TR1 is in the on state.
制御部４−１は、ポートＰ１からバッファ４−２を介してスイッチング素子ＴＲ１のオン／オフを制御する信号を送出し、スイッチング素子ＴＲ１をオン状態とさせたとき、及びオフ状態とさせたときの、接続点ａのそれぞれの電圧を、Ａ／Ｄ変換器４−３を介してポートＰ２から取り込み、該接続点ａの電圧を基に、負荷回路Ｌ１の短絡又は断線、及びスイッチング素子ＴＲ１の短絡故障又は開放故障を検出する。 When the control unit 4-1 sends a signal for controlling on / off of the switching element TR 1 from the port P 1 via the buffer 4-2, and when the switching element TR 1 is turned on and off. The voltage at the connection point a is taken in from the port P2 via the A / D converter 4-3, and the short circuit or disconnection of the load circuit L1 and the switching element TR1 are connected to the voltage at the connection point a. Detects short circuit or open faults.
ポートＰ１からスイッチング素子ＴＲ１をオフ状態にする信号を送出した状態で、ポートＰ２で観測されるａ点の電圧が、
（１）０Ｖのとき、負荷回路Ｌ１は短絡、
（２）第１の電源の電圧Ｂのとき、スイッチング素子ＴＲ１は短絡、
（３）第２の電源の電圧Ｖｃｃのとき、負荷回路Ｌ１は断線、
（４）第２の電源の電圧Ｖｃｃを、抵抗Ｒ２と負荷回路Ｌ１とで分圧した電圧のとき、負荷回路Ｌ１及びスイッチング素子ＴＲ１は正常、又はスイッチング素子ＴＲ１は開放故障と判定する。
In a state where a signal for turning off the switching element TR1 is sent from the port P1, the voltage at the point a observed at the port P2 is
(1) When 0V, the load circuit L1 is short-circuited,
(2) When the voltage B is the first power supply, the switching element TR1 is short-circuited.
(3) When the voltage of the second power source is Vcc, the load circuit L1 is disconnected,
(4) When the voltage Vcc of the second power supply is divided by the resistor R2 and the load circuit L1, it is determined that the load circuit L1 and the switching element TR1 are normal or the switching element TR1 is an open failure.
また、ポートＰ１からスイッチング素子ＴＲ１をオン状態にする信号を送出した状態で、ポートＰ２で観測されるａ点の電圧が、
（１）０Ｖのとき、負荷回路Ｌ１は短絡、
（２）第１の電源の電圧Ｂのとき、負荷回路Ｌ１及びスイッチング素子ＴＲ１は正常、又はスイッチング素子ＴＲ１は短絡故障、又は負荷回路Ｌ１は断線、
（３）第２の電源の電圧Ｖｃｃのとき、スイッチング素子ＴＲ１は開放故障、かつ負荷回路Ｌ１は断線、
（４）第２の電源の電圧Ｖｃｃを、抵抗Ｒ２と負荷回路Ｌ１とで分圧した電圧のとき、スイッチング素子ＴＲ１は開放故障、と判定する。
Further, the voltage at the point a observed at the port P2 in a state where a signal for turning on the switching element TR1 is sent from the port P1,
(1) When 0V, the load circuit L1 is short-circuited,
(2) At the voltage B of the first power supply, the load circuit L1 and the switching element TR1 are normal, the switching element TR1 is a short circuit failure, or the load circuit L1 is disconnected.
(3) When the voltage of the second power supply is Vcc, the switching element TR1 is an open failure, and the load circuit L1 is disconnected.
(4) When the voltage Vcc of the second power source is a voltage divided by the resistor R2 and the load circuit L1, the switching element TR1 is determined to be an open failure.
電動リフト等の負荷回路は、イグニションキーをオフしたときでも、補機類の電装機器を使用し得るようにカスタム化され、ユーザによって任意に投入される各種補機（ヒータ、ライト、警報機等）のスイッチのオン／オフ状態に応じて、負荷回路の抵抗値は、大きな範囲（例えば１Ω〜１ＭΩ）に亘って変動し、また、電流消費量も大きな範囲（例えば０Ａ〜２１Ａ）に亘って変動する。 Load circuits such as electric lifts are customized so that auxiliary electrical equipment can be used even when the ignition key is turned off, and various auxiliary devices (heaters, lights, alarm devices, etc.) that are arbitrarily input by the user The resistance value of the load circuit varies over a large range (for example, 1Ω to 1MΩ), and the current consumption also ranges over a large range (for example, 0A to 21A). fluctuate.
このように負荷回路が大きく変動する場合、負荷回路がどのような状態でも、負荷回路の短絡を精度よく判定することが要求される。例えば、図３の短絡検知用の抵抗３−９の両端の電圧を測定して短絡状態を判定する場合、該電圧は、負荷回路３−３の抵抗と短絡検知用の抵抗３−９との分圧比となる。 When the load circuit fluctuates greatly as described above, it is required to accurately determine a short circuit of the load circuit regardless of the state of the load circuit. For example, when the voltage at both ends of the short-circuit detection resistor 3-9 in FIG. 3 is measured to determine the short-circuit state, the voltage is determined by the resistance of the load circuit 3-3 and the short-circuit detection resistor 3-9. The partial pressure ratio.
そのため、変動する負荷回路３−３の最小負荷抵抗値と、短絡状態の微小抵抗値とを、精度よく判別し得るよう、短絡検知用の抵抗３−９を、負荷回路３−３の最小負荷抵抗値と釣り合った小さな抵抗値とする必要がある。この理由について説明すると、負荷回路３−３の抵抗値をｒ、短絡検知用の抵抗３−９の抵抗値をＲとし、主電源の電圧を４８Ｖとすると、短絡検知用の抵抗３−９の両端の電圧Ｖｄは、
Ｖｄ＝４８・Ｒ／（ｒ＋Ｒ）＝４８／（ｒ／Ｒ＋１）
となる。
Therefore, the short-circuit detection resistor 3-9 is connected to the minimum load of the load circuit 3-3 so that the minimum load resistance value of the fluctuating load circuit 3-3 and the minute resistance value of the short-circuit state can be accurately discriminated. It is necessary to make a small resistance value commensurate with the resistance value. The reason for this will be described. When the resistance value of the load circuit 3-3 is r, the resistance value of the short-circuit detection resistor 3-9 is R, and the voltage of the main power supply is 48V, the short-circuit detection resistor 3-9 The voltage Vd at both ends is
Vd = 48 · R / (r + R) = 48 / (r / R + 1)
It becomes.
従って、（ｒ／Ｒ）の値が、短絡検知の際の判定電圧に影響を与えるので、短絡検知の判定電圧Ｖｄが、短絡したか否かで大きく変化するようにするためには、短絡したか否かで（ｒ／Ｒ）の値が大きく変化するよう、短絡検知用の抵抗３−９の抵抗値Ｒを成るべく小さな値にする必要がある。 Therefore, since the value of (r / R) affects the determination voltage at the time of short circuit detection, in order to change the determination voltage Vd of short circuit detection largely depending on whether or not a short circuit is detected, a short circuit is caused. It is necessary to make the resistance value R of the short-circuit detection resistor 3-9 as small as possible so that the value of (r / R) changes greatly depending on whether or not.
短絡検用の抵抗３−９の抵抗値Ｒを小さくすると、短絡判定時に該短絡検用の抵抗３−９流れる電流が大きくなり、該電流に耐え得る大型の抵抗器を用いなければならない。また、短絡検知用の抵抗３−９の両端の電圧を測定する電圧／電流測定部３−８は、負荷回路３−３の抵抗値ｒが非常に小さい値から非常に大きい値に変化するため、ほぼゼロに近い電圧からほぼ主電源の供給電圧（例えば４８Ｖ）に近い電圧まで変化し、広い範囲に亘る電圧の値を測定し得るものを用いなければならない。 When the resistance value R of the short-circuit detection resistor 3-9 is reduced, the current flowing through the short-circuit detection resistor 3-9 at the time of short-circuit determination increases, and a large resistor that can withstand the current must be used. In addition, the voltage / current measurement unit 3-8 that measures the voltage across the resistor 3-9 for short circuit detection changes the resistance value r of the load circuit 3-3 from a very small value to a very large value. A voltage that changes from a voltage close to zero to a voltage close to a supply voltage of the main power supply (for example, 48 V) and can measure a voltage value over a wide range must be used.
また、短絡検知用の抵抗３−９に流れる電流を測定して短絡状態を判定する場合、該電流は、負荷回路３−３の抵抗と短絡検知用の抵抗３−９との直列回路に流れる電流となる。変動する負荷回路３−３の最小負荷抵抗値と、短絡状態の微小抵抗値とを、精度よく判別し得るようにするには、やはり、短絡検知用の抵抗３−９を、負荷回路３−３の最小負荷抵抗値と釣り合った小さな抵抗値とする必要がある。短絡検用の抵抗３−９の抵抗値を小さくすると、短絡判定時に該短絡検用の抵抗３−９流れる電流が大きくなり、該電流に耐え得る大型の抵抗器を用いなければならない。 When measuring the current flowing through the short-circuit detection resistor 3-9 to determine the short-circuit state, the current flows through a series circuit of the load circuit 3-3 resistance and the short-circuit detection resistor 3-9. It becomes current. In order to be able to accurately determine the minimum load resistance value of the fluctuating load circuit 3-3 and the minute resistance value in the short circuit state, the short circuit detection resistor 3-9 is again connected to the load circuit 3- It is necessary to make the resistance value small in proportion to the minimum load resistance value of 3. When the resistance value of the short-circuit detection resistor 3-9 is reduced, the current flowing through the short-circuit detection resistor 3-9 at the time of short-circuit determination increases, and a large resistor that can withstand the current must be used.
また、短絡検知用の抵抗３−９に流れる電流を測定する電圧／電流測定部３−８は、負荷回路３−３の抵抗値が非常に小さい値から非常に大きい値に変化するため、ほぼゼロに近い電流から、主電源の供給電圧（例えば４８Ｖ）を、微小抵抗を介して短絡したほぼ短絡状態に近い電流に近い電流まで変化し、広い範囲に亘る電流の値を測定し得るものを用いなければならない。 Further, the voltage / current measuring unit 3-8 that measures the current flowing through the resistor 3-9 for detecting the short circuit changes almost from the very small value to the very large value of the load circuit 3-3. What can measure the value of the current over a wide range by changing the supply voltage (for example, 48V) of the main power supply from a current close to zero to a current close to a current that is short-circuited through a very small resistance. Must be used.
また、前述の図４の故障検出回路は、ポートＰ２で観測されるａ点の電圧は、（１）負荷回路Ｌ１が短絡のとき０Ｖ、（２）負荷回路Ｌ１が正常のとき、抵抗Ｒ２と負荷回路Ｌ１とによる第２の電源の電圧Ｖｃｃの分圧電圧、（３）スイッチング素子ＴＲ１をオン状態にしたとき、第１の電源の電圧Ｂとなり、やはり、０Ｖから主電源の電圧Ｂまでの広い範囲に亘る電圧の値となる。従って、Ａ／Ｄ変換器４−３及び制御部４−１は、この広い範囲に亘る電圧の値を測定し得るものでなければならない。 In the failure detection circuit of FIG. 4 described above, the voltage at the point a observed at the port P2 is (1) 0V when the load circuit L1 is short-circuited, and (2) the resistance R2 when the load circuit L1 is normal. The divided voltage of the second power supply voltage Vcc by the load circuit L1, (3) When the switching element TR1 is turned on, it becomes the first power supply voltage B, and again from 0V to the main power supply voltage B The voltage value over a wide range. Therefore, the A / D converter 4-3 and the control unit 4-1 must be able to measure voltage values over this wide range.
上記課題に鑑み、本発明は、負荷回路の抵抗値が大きく変動する場合でも、大電流を流すことなく、従って、短絡検知用の抵抗として小型の低抵抗値のものを用いて、精度よく負荷回路の短絡を検出することができ、かつ、短絡を検出するための測定電圧又は測定電流の値が大きな範囲に亘ることなく、精度よく短絡を検出することが可能な短絡検知回路を提供する。 In view of the above problems, the present invention does not cause a large current to flow even when the resistance value of the load circuit fluctuates greatly. Therefore, the load resistance is accurately obtained by using a small resistance value for detecting a short circuit. Provided is a short-circuit detection circuit that can detect a short circuit and that can detect a short circuit with high accuracy without having a large range of values of a measurement voltage or a measurement current for detecting the short circuit.
本発明に係る短絡検出回路は、主電源の給電端子に第１のスイッチを介して一端が接続され、他端が第２のスイッチを介して接地端子に接続された負荷回路の短絡を検出する短絡検出回路であって、前記主電源の供給電圧より低い、電子制御ユニット用の電圧を供給する低電圧給電部に一端が接続され、他端がダイオードの一端に接続された短絡検知用の抵抗と、前記抵抗と前記ダイオードとの接続点の電圧又は電流を検出する測定部と、前記測定部で測定した電圧又は電流の値を入力する制御部と、前記ダイオードの他端を、前記第１のスイッチと前記負荷回路との接続点に接続する接続線とを備え、前記制御部は、前記第１のスイッチが非導通で、前記第２のスイッチが導通の状態で、前記測定部で測定された電圧が、所定の閾値電圧以下のとき、又は、前記測定部で測定された電流が、所定の閾値電流以上のとき、前記負荷回路が短絡状態であると判定することを特徴とする。 The short circuit detection circuit according to the present invention detects a short circuit of a load circuit in which one end is connected to a power supply terminal of a main power supply via a first switch and the other end is connected to a ground terminal via a second switch. A short-circuit detection circuit, one end of which is connected to a low-voltage power supply unit that supplies a voltage for an electronic control unit that is lower than the supply voltage of the main power supply, and the other end is connected to one end of a diode. A measuring unit that detects a voltage or current at a connection point between the resistor and the diode, a control unit that inputs a voltage or current value measured by the measuring unit, and the other end of the diode. And a connection line connected to a connection point between the load circuit and the load circuit, and the control unit performs measurement with the measurement unit when the first switch is non-conductive and the second switch is conductive. Is not less than a predetermined threshold voltage. When, or, the measured measured at section current, when more than a predetermined threshold current, and judging the said load circuit is a short circuit condition.
また、前記低電圧給電部、前記抵抗、前記ダイオード、前記測定部及び前記制御部は、電子制御ユニット用の一つの基板上に実装されたことを特徴とする。
また、前記負荷回路は、抵抗値が変化する負荷回路であり、前記短絡検知用の抵抗は、該負荷回路の変化する抵抗値のうちの最小の抵抗値及び許容される電流の上限を基に決定された抵抗値のものであることを特徴とする。
The low voltage power supply unit, the resistor, the diode, the measurement unit, and the control unit are mounted on a single substrate for an electronic control unit.
Further, the load circuit is a load circuit whose resistance value changes, and the resistance for detecting the short circuit is based on a minimum resistance value and an upper limit of an allowable current among the resistance values which the load circuit changes. The resistance value is determined.
本発明によれば、低電圧の電子制御ユニット用の電圧を供給して、短絡検知用の電流を流し、短絡判定を行うことにより、短絡検知用の抵抗として低抵抗値のものを用いても、主電源の電圧を供給した場合に比べて、小電流の給電で短絡を検知することができ、短絡検知用の抵抗の小型化を図ることができる。 According to the present invention, by supplying a voltage for a low-voltage electronic control unit, passing a current for short-circuit detection, and performing a short-circuit determination, a resistor having a low resistance value can be used as a short-circuit detection resistor. As compared with the case where the voltage of the main power supply is supplied, a short circuit can be detected by feeding a small current, and the resistance for detecting the short circuit can be reduced in size.
また、短絡検知の観測点の電圧又は電流の値の範囲が、主電源の電圧を供給した場合に比べて狭い範囲となり、該観測点の電圧又は電流を測定する電圧／電流測定部等の部品に高耐圧性や高耐電流性の電子部品を用いることなく、短絡検知回路の部品を電子制御ユニットと同一の基板上に実装することが可能となる。従って、一つの基板上に実装された短絡検知回路を、１本の接続線で負荷回路の一端に接続するだけで、負荷回路の短絡を検出することが可能となる。 In addition, the voltage or current value range at the observation point for short circuit detection is narrower than that when the main power supply voltage is supplied, and components such as a voltage / current measurement unit that measures the voltage or current at the observation point In addition, it is possible to mount the components of the short-circuit detection circuit on the same substrate as the electronic control unit without using electronic components with high withstand voltage and high current resistance. Therefore, it is possible to detect a short circuit of the load circuit only by connecting the short circuit detection circuit mounted on one substrate to one end of the load circuit with a single connection line.
本発明の短絡検知回路の構成例を図１に示す。図１に示すように、負荷回路３−３は、主電源３−１の給電端子に第１のスイッチ３−２を介して一端が接続され、他端がメインスイッチ３−４を介して接地端子３−５に接続される。 A configuration example of the short circuit detection circuit of the present invention is shown in FIG. As shown in FIG. 1, the load circuit 3-3 has one end connected to the power supply terminal of the main power source 3-1 via the first switch 3-2 and the other end grounded via the main switch 3-4. Connected to terminal 3-5.
この負荷回路３−３に対して、電子制御ユニット１−１０内に、主電源３−１の電圧より低い電子制御ユニット用の電圧を供給する低電圧給電部１−１と、短絡検知用の抵抗１−２と、ダイオード１−３と、電圧／電流測定部１−４と、制御部１−５とを備えた短絡検出回路を構成する。 A low-voltage power supply unit 1-1 that supplies a voltage for an electronic control unit lower than the voltage of the main power supply 3-1 in the electronic control unit 1-10 to the load circuit 3-3, and a short-circuit detection unit A short circuit detection circuit including a resistor 1-2, a diode 1-3, a voltage / current measurement unit 1-4, and a control unit 1-5 is configured.
低電圧給電部１−１は、例えば５Ｖ又は１２Ｖ等、主電源３−１の電圧４８Ｖに比べて約１０分の１〜４分の１程度の低い電圧を供給する。短絡検知用の抵抗１−２は、低電圧給電部１−１に一端が接続され、他端がダイオード１−３の一端に接続される。ダイオード１−３の他端は、第１のスイッチ３−２と負荷回路３−３との接続点に、接続線１−６により接続される。そして、短絡検知用の抵抗１−２とダイオード１−３との接続点を観測点とし、該観測点の電圧又は電流を電圧／電流測定部１−４により測定する。 The low voltage power supply unit 1-1 supplies a low voltage of about 1/10 to 1/4 of the voltage 48V of the main power source 3-1, such as 5V or 12V. The resistor 1-2 for short circuit detection has one end connected to the low voltage power supply unit 1-1 and the other end connected to one end of the diode 1-3. The other end of the diode 1-3 is connected to a connection point between the first switch 3-2 and the load circuit 3-3 by a connection line 1-6. Then, the connection point between the short-circuit detection resistor 1-2 and the diode 1-3 is taken as an observation point, and the voltage or current at the observation point is measured by the voltage / current measurement unit 1-4.
電圧／電流測定部１−４は、測定した電圧又は電流の値を制御部１−５に通知する。制御部１−５は、第１のスイッチ３−２を非導通とし、第２のスイッチ３−４が導通した状態で、短絡検知用の抵抗１−２とダイオード１−３との接続点（観測点）の電圧を、所定の閾値と比較し、該接続点（観測点）の電圧が所定の閾値以下のとき、負荷回路３−３が短絡状態であると判定する。 The voltage / current measurement unit 1-4 notifies the control unit 1-5 of the measured voltage or current value. The control unit 1-5 makes the first switch 3-2 non-conductive and the second switch 3-4 is conductive, and the connection point between the short-circuit detection resistor 1-2 and the diode 1-3 ( The voltage at the observation point) is compared with a predetermined threshold, and when the voltage at the connection point (observation point) is equal to or lower than the predetermined threshold, it is determined that the load circuit 3-3 is in a short circuit state.
このように、短絡判定時に、主電源３−１と負荷回路とを接続する正極側の第１のスイッチ３−２を非導通とし、主電源３−１の電圧ではなく、電池ＥＣＵ等の電子制御ユニット１−１０の電源である低電圧給電部１−１から低電圧（５Ｖや１２Ｖ等の電圧）を短絡検知に用いる。 As described above, when the short circuit is determined, the first switch 3-2 on the positive electrode side connecting the main power source 3-1 and the load circuit is made non-conductive, and not the voltage of the main power source 3-1 but the electronic device such as the battery ECU. A low voltage (voltage such as 5 V or 12 V) is used for short circuit detection from the low voltage power supply unit 1-1 which is a power source of the control unit 1-10.
そして、該低電圧給電部１−１から低電圧を、短絡検知用の抵抗１−２と負荷回路３−３の抵抗とにより分圧した観測点の電圧又は電流を測定することによって、短絡の判定を行う。なお、短絡検知用の抵抗１−２の抵抗値は、負荷回路３−３の変化する抵抗値のうちの最小の抵抗値及び許容される電流の上限値を基に決定される。 Then, by measuring the voltage or current at the observation point obtained by dividing the low voltage from the low voltage power supply unit 1-1 by the resistance 1-2 for short circuit detection and the resistance of the load circuit 3-3, Make a decision. In addition, the resistance value of the resistance 1-2 for detecting the short circuit is determined based on the minimum resistance value among the changing resistance values of the load circuit 3-3 and the upper limit value of the allowable current.
図２に、負荷回路３−３の抵抗値の変化に対して観測される観測点の電圧の変化の一例を示す。同図の（ａ）は、負荷回路のスイッチがオフの状態で、負荷回路の抵抗値が１ＭΩの状態のとき、（ｂ）は、負荷回路のスイッチがオンの状態で、負荷回路の抵抗値が１Ωの状態のとき、（ｃ）は、負荷回路が短絡状態で、負荷回路の抵抗値が０．１Ωの状態のとき、それぞれの観測点の電圧を示している。 FIG. 2 shows an example of the change in the voltage at the observation point observed with respect to the change in the resistance value of the load circuit 3-3. (A) in the figure is when the load circuit switch is off and the load circuit resistance is 1 MΩ, and (b) is when the load circuit switch is on and the load circuit resistance is on. (C) shows the voltage at each observation point when the load circuit is in a short circuit state and the resistance value of the load circuit is 0.1Ω.
ここで、低電圧給電部１−１から５Ｖの低電圧が供給されるものとし、短絡検知用の抵抗１−２は４Ωであるとする。また、ダイオード１−３の通電時の電圧降下が０．６Ｖであるとする。 Here, it is assumed that a low voltage of 5 V is supplied from the low-voltage power supply unit 1-1, and the resistance 1-2 for short circuit detection is 4Ω. Further, it is assumed that the voltage drop when the diode 1-3 is energized is 0.6V.
（ａ）に示す負荷回路の抵抗値が１ＭΩのとき、観測点の電圧Ｖｄは、
Ｖｄ＝（５−０．６）÷（４＋１００００００）×１００００００＋０．６＝５．０Ｖ
となる。また、このとき流れる電流Ｉｄは、
Ｉｄ＝（５−０．６）÷（４＋１００００００）＝４．４μＡ
となる。
When the resistance value of the load circuit shown in (a) is 1 MΩ, the voltage Vd at the observation point is
Vd = (5-0.6) ÷ (4 + 1000000) × 1000000 + 0.6 = 5.0V
It becomes. The current Id flowing at this time is
Id = (5-0.6) ÷ (4 + 1000000) = 4.4 μA
It becomes.
（ｂ）に示す負荷回路の抵抗値が１Ωのとき、観測点の電圧Ｖｄは、
Ｖｄ＝（５−０．６）÷（４＋１）×１＋０．６＝１．４８Ｖ
となる。また、このとき流れる電流Ｉｄは、
Ｉｄ＝（５−０．６）÷（４＋１）＝０．８８Ａ
となる。
When the resistance value of the load circuit shown in (b) is 1Ω, the voltage Vd at the observation point is
Vd = (5-0.6) ÷ (4 + 1) × 1 + 0.6 = 1.48V
It becomes. The current Id flowing at this time is
Id = (5-0.6) ÷ (4 + 1) = 0.88A
It becomes.
（ｃ）に示す負荷回路の抵抗値が０．１Ωのとき、観測点の電圧Ｖｄは、
Ｖｄ＝（５−０．６）÷（４＋０．１）×０．１＋０．６＝０．７０７３Ｖ
となる。また、このとき流れる電流Ｉｄは、
Ｉｄ＝（５−０．６）÷（４＋０．１）＝１．０７３Ａ
となる。
When the resistance value of the load circuit shown in (c) is 0.1Ω, the voltage Vd at the observation point is
Vd = (5-0.6) ÷ (4 + 0.1) × 0.1 + 0.6 = 0.0703V
It becomes. The current Id flowing at this time is
Id = (5-0.6) ÷ (4 + 0.1) = 1.003A
It becomes.
短絡か否かは、観測点の電圧Ｖｄを基に判定する。短絡と判定する閾値は、（ｂ）と（ｃ）の電圧の中間値、例えば１．１Ｖとして設定し、電圧Ｖｄが１．１Ｖ以下であれば、短絡と判定する。電流で判定する場合には、（ｂ）と（ｃ）の電流の中間値、例えば０．９８Ａとして設定し、電流が０．９８Ａ以上であれば、短絡と判定する。 Whether or not it is a short circuit is determined based on the voltage Vd at the observation point. The threshold value for determining a short circuit is set as an intermediate value between the voltages of (b) and (c), for example, 1.1 V, and if the voltage Vd is 1.1 V or less, it is determined that a short circuit. When determining by current, it is set as an intermediate value between the currents of (b) and (c), for example, 0.98 A, and if the current is 0.98 A or more, it is determined as a short circuit.
図２に示した例から分かるように、観測点の電圧Ｖｄは、０．７０７３Ｖから５．０Ｖの範囲、その電流Ｉｄは、４．４μＡから１．０７３Ａの範囲となり、従来、主電源３−１の例えば４８Ｖを給電して観測した場合と比べて、約１０分の１まで、電流量を低減することができ、その分、短絡検知用の抵抗として小型の抵抗を用いることができる。また、観測点の電圧又は電流を測定する電圧／電流測定部１−４の測定範囲の値も、約１０分の１に減少する。 As can be seen from the example shown in FIG. 2, the voltage Vd at the observation point is in the range of 0.7073 V to 5.0 V, and the current Id is in the range of 4.4 μA to 1.073 A. The amount of current can be reduced to about one-tenth compared with the case of observation with power supply of 48 V, for example, and a small resistor can be used as a short-circuit detection resistor. In addition, the value of the measurement range of the voltage / current measurement unit 1-4 that measures the voltage or current at the observation point is also reduced to about 1/10.
そのため、高耐圧性の電子部品等を用いることなく、これらの短絡検知回路の部品を電子制御ユニットと同一の基板上に実装することが可能となる。従って、一つの基板上に実装した短絡検知回路を、１本の接続線１−６で負荷回路３−３の一端に接続するだけで、負荷回路３−３の短絡を検出することが可能となる。また、図３に示した従来の短絡検知回路におけるリレー３−１０を省くことが可能となる。 Therefore, it is possible to mount these short-circuit detection circuit components on the same substrate as the electronic control unit without using high-voltage resistant electronic components or the like. Therefore, it is possible to detect a short circuit of the load circuit 3-3 by simply connecting the short circuit detection circuit mounted on one substrate to one end of the load circuit 3-3 with one connection line 1-6. Become. Moreover, it becomes possible to omit the relay 3-10 in the conventional short circuit detection circuit shown in FIG.
なお、本発明は、以上に述べた実施の形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内で種々の構成または実施形態を取ることができる。 The present invention is not limited to the above-described embodiment, and various configurations or embodiments can be taken without departing from the gist of the present invention.
１−１ 低電圧給電部
１−２ 短絡検知用の抵抗
１−３ ダイオード
１−４ 電圧／電流測定部
１−５ 制御部
１−６ 接続線
１−１０ 電子制御ユニット
３−１ 主電源
３−２ 第１のスイッチ
３−３ 負荷回路
３−４ メインスイッチ
３−５ 接地端子
1-1 Low voltage power supply unit 1-2 Resistance for short circuit detection 1-3 Diode 1-4 Voltage / current measurement unit 1-5 Control unit 1-6 Connection line 1-10 Electronic control unit 3-1 Main power supply 3- 2 First switch 3-3 Load circuit 3-4 Main switch 3-5 Ground terminal
Claims (3)
前記主電源の供給電圧より低い、電子制御ユニット用の電圧を供給する低電圧給電部に一端が接続され、他端がダイオードの一端に接続された短絡検知用の抵抗と、
前記抵抗と前記ダイオードとの接続点の電圧又は電流を検出する測定部と、
前記測定部で測定した電圧又は電流の値を入力する制御部と、
前記ダイオードの他端を、前記第１のスイッチと前記負荷回路との接続点に接続する接続線とを備え、
前記制御部は、前記第１のスイッチが非導通で、前記第２のスイッチが導通の状態で、前記測定部で測定された電圧が、所定の閾値電圧以下のとき、又は、前記測定部で測定された電流が、所定の閾値電流以上のとき、前記負荷回路が短絡状態であると判定することを特徴とする短絡検出回路。 A short circuit detection circuit for detecting a short circuit of a load circuit having one end connected to a power supply terminal of a main power supply via a first switch and the other end connected to a ground terminal via a second switch;
One end connected to a low-voltage power supply unit that supplies a voltage for an electronic control unit that is lower than the supply voltage of the main power source, and the other end is connected to one end of a diode, and a resistance for short-circuit detection,
A measurement unit for detecting a voltage or current at a connection point between the resistor and the diode;
A control unit for inputting a voltage or current value measured by the measurement unit;
A connection line that connects the other end of the diode to a connection point between the first switch and the load circuit;
The control unit is configured such that when the first switch is non-conductive and the second switch is conductive and the voltage measured by the measurement unit is equal to or lower than a predetermined threshold voltage, or the measurement unit When the measured current is equal to or greater than a predetermined threshold current, it is determined that the load circuit is in a short circuit state.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105425091A (en) * | 2015-11-09 | 2016-03-23 | 上海凌翼动力科技有限公司 | Large-power circuit connection resistance fault dynamic simulation system and method, and application |
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| JP2017210936A (en) * | 2016-05-27 | 2017-11-30 | 日立オートモティブシステムズ株式会社 | Fault diagnosis equipment for electromagnetic load driving circuit |
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-
2012
- 2012-11-07 JP JP2012244982A patent/JP2014091495A/en active Pending
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| KR20160148933A (en) * | 2015-06-17 | 2016-12-27 | 한국단자공업 주식회사 | Diagnostic method of smart power relay assembly |
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| CN105425091A (en) * | 2015-11-09 | 2016-03-23 | 上海凌翼动力科技有限公司 | Large-power circuit connection resistance fault dynamic simulation system and method, and application |
| JP2017210936A (en) * | 2016-05-27 | 2017-11-30 | 日立オートモティブシステムズ株式会社 | Fault diagnosis equipment for electromagnetic load driving circuit |
| KR20180053155A (en) * | 2016-11-11 | 2018-05-21 | 현대오트론 주식회사 | An Apparatus And A Method For Detecting Short Circuit Of A Controller |
| KR101887904B1 (en) | 2016-11-11 | 2018-08-13 | 현대오트론 주식회사 | An Apparatus And A Method For Detecting Short Circuit Of A Controller |
| CN108539831A (en) * | 2017-03-02 | 2018-09-14 | 深圳市昭恒新能源技术有限公司 | A kind of short-circuit detecting circuit of charging equipment and its output end |
| CN110907837B (en) * | 2018-09-14 | 2021-06-08 | 宁德时代新能源科技股份有限公司 | Detection circuit and detection method |
| CN110907837A (en) * | 2018-09-14 | 2020-03-24 | 宁德时代新能源科技股份有限公司 | Detection circuit and detection method |
| CN110907853A (en) * | 2018-09-17 | 2020-03-24 | 宁德时代新能源科技股份有限公司 | Load state detection circuit and method |
| CN112858949A (en) * | 2018-09-17 | 2021-05-28 | 宁德时代新能源科技股份有限公司 | Load state detection circuit |
| US10983154B2 (en) | 2018-09-17 | 2021-04-20 | Contemporary Amperex Technology Co., Limited | Load state detection circuit and method |
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