Control circuit and control unit for vehicle

Abstract

The invention relates to a control circuit (10) for a control unit (12) located in a vehicle and capable of switching between an energy-saving state with a limited range of functions and a normal operating state depending on an output voltage (Ua), the output voltage being variable via the control circuit (10) and being applied to the output side of the control circuit (10), the control circuit (10) having at least one field effect transistor (FET) controllable by a control voltage (Ug) at a gate terminal (G) and having a supply voltage (U0) applied to its input side, the output voltage (Ua) being dependent on the control state of the field effect transistor (FET). The invention also relates to a control unit (12) for a vehicle, the control unit being intended to control at least one vehicle component and having such a control circuit (10).

Description

Technical Field

[0001] The present invention relates to a control circuit for a vehicle. Furthermore, the present invention relates to a control unit having such a control circuit. Background Art

[0002] A control circuit for a control unit in a motor vehicle can induce an energy-saving state or a normal operating state of the control unit, depending on the output voltage provided on the output side of the control circuit. In the energy-saving state, the control unit's power consumption is significantly reduced, and thus, a small portion of the vehicle's battery capacity is occupied. A control unit triggered by a wake-up event can be switched to a normal operating state by the control circuit via the output voltage and can perform the functions assigned to the control unit. Summary of the Invention

[0003] The present invention aims to provide a more energy-efficient control circuit. The power consumption of the control circuit in the energy-saving state is further reduced. In particular, the power consumption in the energy-saving state should be less than or equal to 100 μA.

[0004] At least one of these objectives is achieved by the control circuit of the present invention. Thus, the control circuit can be operated more reliably. The quiescent current required in the energy-saving state can be reduced. In particular, the quiescent current can be lower than 100 μA.

[0005] The output voltage may be the drain-source voltage of the field effect transistor. The output voltage may be directly dependent on the supply voltage. The supply voltage may be dependent on the on position of an on element of the vehicle. The on element may be a vehicle on button. The supply voltage may be applied to a KL 15 connection on the vehicle.

[0006] The field effect transistor can be a p-channel MOSFET or an n-channel MOSFET.

[0007] When the field effect transistor is turned on, the output voltage may be equal to the supply voltage. The supply voltage may depend on the battery supply voltage. The battery supply voltage may be provided by a vehicle battery, in particular a 12 V, 24 V or 48 V battery.

[0008] In a preferred embodiment of the present invention, the control circuit includes a first switching element that switches the control voltage on according to a ratio between the supply voltage and a first voltage value. The first voltage value may be between 20% and 80% of the supply voltage. The first voltage value may correspond to a turn-on voltage of the field effect transistor.

[0009] In a specific embodiment of the invention, the gate terminal of the first switching element is connected to the input side of the field effect transistor.Thus, the first switching element can be switched via the supply voltage.

[0010] In another embodiment of the present invention, the first voltage value can be set via a voltage divider assigned to the gate connection portion of the first switching element. Therefore, the first voltage value can be set easily and at a low cost.

[0011] In a preferred embodiment of the present invention, the control circuit has a second switching element that switches on the control voltage according to the ratio between the output voltage and the second voltage value. Therefore, the control voltage of the conductive field effect transistor can be controlled independently of the switching state of the first switching element.

[0012] The second voltage value may be between 20% and 80% of the output voltage and / or the supply voltage.The second voltage value may correspond to a turn-off voltage of the field effect transistor.

[0013] In a special embodiment of the invention, the gate connection of the second switching element is connected to the output side of the field effect transistor. Thus, the second switching element can be switched depending on the output voltage.

[0014] In a particularly preferred embodiment of the present invention, the first voltage value is greater than the second voltage value. The first voltage value may be 10% to 50% higher than the second voltage value.

[0015] In a specific embodiment of the present invention, the first switching element and the second switching element are connected in parallel between the gate connection portion of the field effect transistor and the ground. Therefore, the control voltage of the field effect transistor can be controlled by the first switching element and the second switching element.

[0016] In a preferred embodiment of the present invention, the first switching element and the second switching element have the same structure. Therefore, the control circuit can be realized at a low cost.

[0017] In order to solve at least one of the above tasks, a control unit for a vehicle is also proposed, which is used to control at least one vehicle component. The control unit has a control circuit having at least one of the above features to switch between an energy-saving state and a normal operating state.

[0018] The control unit may be a vehicle control unit. The control unit may control at least one vehicle component of the vehicle, such as a drive element and / or a clutch. The control unit may be supplied with a battery supply voltage. The battery supply voltage may also be present at the control unit when the vehicle is disconnected. The battery supply voltage may be 12 V, 24 V, or 48 V.

[0019] Further advantages and advantageous embodiments of the invention are apparent from the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described in detail below with reference to the accompanying drawings. Specifically:

[0021] Figure 1 : Shows the control circuit and control unit in a specific embodiment of the present invention.

[0022] Figure 2 : shows a side view of a control circuit in another specific embodiment of the present invention. DETAILED DESCRIPTION

[0023] Figure 1 The control circuit 10 and control unit 12 of a specific embodiment of the present invention are shown. The control unit 12 can be provided in a vehicle to control at least one vehicle component and has an energy-saving state in which the power consumption of the control unit 12 is reduced. Therefore, if the functions of the control unit 12 are not required or only partially required, the power used to power the control unit 12 can be conserved. For example, the energy-saving state can be entered when the vehicle is not in use.

[0024] The vehicle may have a switch-on element, such as a start button, that can be used to switch the vehicle on and off depending on its position. The vehicle supplies power to various components and the control unit 12 from the vehicle battery, which outputs a battery supply voltage and has a limited capacity. The presence of supply voltage U0 depends on the switch-on position. For example, if the switch-on element is on, supply voltage U0 equals the battery supply voltage after a run-in period. On the other hand, if the switch-on element is off, the supply voltage is zero. Supply voltage U0 may be the terminal voltage at KL 15.

[0025] If several components are operated at the battery supply voltage when the vehicle is disconnected, the capacity of the vehicle battery may be quickly depleted. For this reason, it is advantageous to place various components including the control unit 12 in an energy-saving state with reduced power consumption, particularly when the vehicle is disconnected.

[0026] The control unit 12 can switch between the energy-saving state and the normal operation state according to the output voltage Ua of the control circuit 10. For this purpose, the control unit 12 is electrically connected to the control circuit 10. In addition, the control circuit 10 can be built into the control unit 12.

[0027] An output voltage Ua is applied to the output side of the control circuit 10 and to the input side of the control unit 12. The control circuit 10 includes a field-effect transistor FET, which can be controlled by a control voltage Ug at a gate connection G. The output voltage Ua depends on the control state of the field-effect transistor FET. Therefore, the power consumption of the control circuit 10 can be reduced even in the energy-saving mode. The quiescent current required by the control circuit 10 in the energy-saving mode is less than 100 μA, thus meeting the strict requirements on vehicle energy consumption.

[0028] The output voltage Ua and the control voltage Ug depend on the supply voltage U0, in particular on the terminal voltage at KL 15, and are controlled by a first switching element S1 of the control circuit 10. The first switching element S1 is preferably designed as an npn transistor and switches the control voltage Ug via a gate connection G1 on the first switching element S1 as a function of the ratio between the supply voltage U0 and a first voltage value.

[0029] The supply voltage U0 can be between 0 V and the battery supply voltage, in particular 12 V. The gate connection G1 is connected to the supply voltage U0 on the input side of the field effect transistor FET via a first voltage divider T1 formed by a first resistor R1 and a second resistor R2, the first resistor in particular having a value of 10 kiloohms and the second resistor in particular having a value of 1200 ohms. The first voltage value can be set via the first voltage divider T1.

[0030] As soon as the supply voltage U0 reaches a first voltage value, for example, 5.37 V, the first switching element S1 is switched on and a control voltage Ug is applied to the gate connection G of the field-effect transistor FET via a third resistor R3, which typically has a value of 10 kiloohms. The field-effect transistor FET is thus switched on, and an output voltage Ua corresponding to the supply voltage U0 is applied to the output side of the field-effect transistor FET. The third resistor R3 is a pull-up resistor, across which the control voltage Ug remains absent as long as the first switching element S1 is locked. A fourth resistor R4 is operatively arranged in series between the gate connection G and the first switching element S1 and serves to limit the current through the first switching element S1. The fourth resistor typically has a value of 8200 ohms.

[0031] The field-effect transistor FET is preferably designed as a MOSFET, in particular as a p-channel MOSFET. A pull-down resistor Rd having a value of 33 kilohm is provided on the output side of the field-effect transistor FET; this pull-down resistor can also be omitted depending on the requirements of the control unit 12. A diode D is provided on the input side of the field-effect transistor FET and connected to the gate connection G for overvoltage protection of the field-effect transistor FET.

[0032] The second switching element S2, which is preferably designed structurally identical to the first switching element S1, has a gate connection G2 and is connected to the output side of the field-effect transistor FET. The second switching element S2 is preferably designed as an npn transistor. The output voltage Ua is applied to the gate connection G2 via a fifth resistor R5, which typically has a value of 1 kiloohm.

[0033] In particular, the sixth resistor R6, which has a value of 8200 ohms, limits the current through the second switching element S2. Even when the first switching element S1 is locked, the second switching element S2 enables the control voltage Ug when the field effect transistor FET is switched on. Thus, the control voltage Ug can be present via the second voltage divider T2 formed by the third resistor R3 and the sixth resistor R6 at a voltage higher than the second voltage value of the supply voltage U0 or the output voltage Ua.

[0034] The second voltage value is preferably smaller than the first voltage value. Therefore, the switch-on voltage of the supply voltage U0 corresponding to the first voltage value is different from the switch-off voltage of the output voltage Ua corresponding to the second voltage value.

[0035] Figure 2 The voltage diagram of the control circuit in another embodiment of the present invention is shown. If the supply voltage U0 is switched on, it increases over time and once it reaches a first voltage value U1, the field effect transistor is switched on and the output voltage UA is equal to the supply voltage U0.

[0036] If the supply voltage U0 is disconnected, it decreases over time and the field effect transistor remains switched on above the second voltage value U2 and only when the supply voltage U0 falls below the second voltage value U2 does the field effect transistor switch off and no voltage is present on the output side.

[0037] Reference Signs List

[0038] 10 Control Circuit

[0039] 12 Control Unit

[0040] D diode

[0041] G Gate connection

[0042] G1 Gate connection

[0043] G2 Gate connection

[0044] Resistors R1 to R6

[0045] S1 First switching element

[0046] S2 Second switching element

[0047] U0 supply voltage

[0048] U1 first voltage value

[0049] U2 second voltage value

[0050] Ua output voltage

[0051] Ug control voltage.

Claims

1. A control circuit (10) for a control unit (12) provided in a vehicle, the control circuit being capable of switching between an energy-saving state with a limited range of functions and a normal operating state depending on an output voltage (Ua), the output voltage being variable via the control circuit (10) and being applied to an output side of the control circuit (10), It is characterized by: The control circuit (10) has at least one field effect transistor (FET) which can be controlled by a control voltage (Ug) at a gate connection (G) and to which a supply voltage (U0) is applied on the input side, and The output voltage (Ua) depends on the control state of the field effect transistor (FET); The control circuit (10) has a first switching element (S1), which switches the control voltage (Ug) according to the ratio between the supply voltage (U0) and the first voltage value (U1); the gate connection (G1) of the first switching element (S1) is connected to the input side of the field effect transistor (FET); The control circuit (10) has a second switching element (S2), which switches on the control voltage (Ug) according to a ratio between the output voltage (Ua) and a second voltage value (U2); the first voltage value (U1) is greater than the second voltage value (U2); When the first switching element (S1) is locked, the second switching element (S2) enables the control voltage (Ug) when the field effect transistor is turned on.

2. The control circuit (10) according to claim 1, characterized in that The first voltage value (U1) can be set via a voltage divider (T1) assigned to the gate connection (G1) of the first switching element (S1).

3. The control circuit (10) according to claim 1, characterized in that The gate connection (G2) of the second switching element (S2) is connected to the field effect transistor (FET) on the output side of the field effect transistor.

4. The control circuit (10) according to claim 1, characterized in that The first switching element and the second switching element (S1, S2) are connected in parallel between a gate connection portion (G) of the field effect transistor (FET) and ground.

5. The control circuit (10) according to claim 1, characterized in that The first switching element and the second switching element (S1, S2) have the same structure.

6. A control unit (12) for a vehicle for controlling at least one vehicle component, the control unit having a control circuit (10) according to any one of the preceding claims for switching between an energy-saving mode and a normal operating mode.

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