Ignition sensing and control circuit for vehicle and off-highway vehicles for electronic control unit (ECU)

Abstract

A low cost compact ignition sensing and control circuit is powered by a battery supply line of a vehicle and receives an ignition input signal indicative of the on / off of the vehicle. In response to the ignition input signal, the ignition sensing and control circuit controls the on / off state of a main internal power supply of an ECU or controls the activation / deactivation state of a microprocessor of the ECU using first and second MOSFETs. When the MOSFETs are on, voltage from the battery supply line is used to latch the main internal power supply of the ECU to an on state or to latch the microprocessor of the ECU to an on state. An off signal at the ignition input signal releases the latches to provide an off of the main internal power supply or the microprocessor.

Description

[0001] This application was filed as a PCT international patent application on June 30, 2022, and claims the benefit and priority of Indian Provisional Patent Application No. 202111029355, filed in 2021, the entire disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure relates to an ignition sensing and control circuit, and more specifically, to an ignition sensing and control circuit for an electronic control unit used in motor vehicle applications and off-road motor vehicle applications. Background Technology

[0003] An electronic control unit (ECU) is a component that typically includes a microprocessor, internal power supply, memory, communication interface unit, and signal processing unit programmed to control one or more electronic functions of a vehicle or off-road vehicle. For example, an ECU may be used to control multiple solenoid coils actuating hydraulic valves in the hydraulic system of an off-road vehicle, or it may be used to drive the vehicle's electric motor. When the ECU is used to drive high-power loads (such as solenoid coils and electric motors), the ECU's power supply is directly connected to the vehicle's battery to reduce the current load on the ignition switch. An ECU typically also includes circuitry for sensing the state of the ignition needle to control the ECU's operating state. Summary of the Invention

[0004] According to this disclosure, a low-cost, compact ignition sensing and control circuit can replace the logic gates, operational amplifier integrated circuits (ICs), reference signal ICs, and reference power ICs commonly found in standard or typical ignition sensing and control circuits of electronic control units (ECUs) in vehicles or off-road vehicles. This low-cost, compact ignition sensing and control circuit is powered by the vehicle's battery power supply line and receives an ignition input signal indicating that the vehicle is on / off. In response to the ignition input signal, the ignition sensing and control circuit utilizes first and second MOSFETs to control the on / off state of the ECU's main internal power supply or the activation / deactivation state of the ECU's microprocessor. When the MOSFETs are turned on, the voltage from the battery power supply line is used to latch the ECU's main internal power supply to the on state or the ECU's microprocessor to the on state. A shutdown signal at the ignition input signal releases the latches to provide shutdown of the main internal power supply or the microprocessor, respectively.

[0005] Various additional inventive aspects will be set forth in the following description. These inventive aspects may involve individual features as well as combinations of features. It will be understood that both the foregoing general description and the following detailed description are exemplary and illustrative only, and do not limit the broad inventive concept on which the embodiments disclosed herein are based. Attached Figure Description

[0006] Figure 1 This is a block diagram example of a typical prior art ignition sensing and control circuit.

[0007] Figures 2A to 2B These are the circuit diagram and block diagram of the ignition sensing and control circuit according to this disclosure.

[0008] Figure 3 It is a block diagram illustrating the use of ignition sensing and control circuitry to control the internal power supply of an electronic control unit (ECU).

[0009] Figure 4 It is a block diagram showing the microprocessor that uses ignition sensing and control circuitry to control the electronic control unit (ECU). Detailed Implementation

[0010] Various embodiments will be described in detail with reference to the accompanying drawings, wherein similar reference numerals denote similar parts and components in several views. Reference to various embodiments does not limit the scope of the appended claims. Furthermore, any examples set forth in this specification are not intended to be limiting and are merely illustrative of some of the many possible embodiments of the appended claims.

[0011] Where appropriate, a term used in the singular will also include the plural, and vice versa. As used herein, “a” means “one or more” unless otherwise stated or clearly inappropriate. The use of “or” means “and / or” unless otherwise stated. The use of “comprise” and “comprises” is interchangeable and not intended to be restrictive. The term “for example” is also not intended to be restrictive. Further, for example, the term “including” should mean “including, but not limited to”.

[0012] According to this disclosure, a low-cost, compact ignition sensing and control circuit can replace the logic gates, operational amplifier integrated circuits (ICs), reference signal ICs, and reference power supply ICs commonly found in standard or typical ignition sensing and control circuits of electronic control units (ECUs) in vehicles or off-road vehicles. This low-cost, compact ignition sensing and control circuit is powered by the vehicle's battery power supply line and receives an ignition input signal indicating whether the vehicle is on or off. In response to the ignition input signal, the ignition sensing and control circuit utilizes first and second MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) Q1A and Q2A to control the on / off state of the ECU's main internal power supply or the activation / deactivation state of the ECU's microprocessor. When MOSFETs Q1A and Q2A are turned on, the voltage from the battery power supply line is used to latch the ECU's main internal power supply to the on state or the ECU's microprocessor to the on state. A shutdown signal at the ignition input signal releases the latch, thereby shutting down the main internal power supply or the microprocessor, respectively.

[0013] refer to Figure 1 This illustrates an example of a typical prior art ignition sensing and control circuit 10. As shown, a typical ignition sensing and control circuit 10 for an electronic control unit (ECU) in a vehicle or off-road vehicle to enable or disable the vehicle includes: a comparator 12 (implemented using logic gates or operational amplifier integrated circuits (ICs); a reference IC 14 for power supply and a reference IC 15 for generating a reference signal; latch logic 16 (typically implemented using one or more transistors); an ignition signal monitor 18 (typically implemented using one or more resistors); and an enable circuit 20 (typically implemented using one or more transistors). In this typical circuit, an enable signal is generated when the output of comparator 12 is active, supplying power to the ECU and / or a microcontroller (not shown); the output of comparator 12 is active when the ignition input signal is greater than the reference signal. The ignition latch signal is generated by the ECU's microcontroller to latch the output state of the enable logic 20 after a first enable signal is successfully generated. By using the ignition signal monitor 18 to monitor the ignition sensing signal, the ECU's microcontroller can make a decision about when to release the ignition latch signal to safely shut down the ECU. This typical implementation utilizes a large number of electronic components, resulting in a potentially space-consuming and costly configuration. Therefore, if cost and printed circuit board (PCB) space constraints are a concern, the typical ignition sensing and control circuitry 10 needs to be redesigned.

[0014] refer to Figure 2AThe ignition sensing and control circuit 100 disclosed herein provides a circuit configuration with reduced component count, enabling a more compact PCB presentation and lower cost. The ignition sensing and control circuit 100 is used in vehicles or off-road vehicles to enable or disable the vehicle's electronic control unit (ECU). As shown, the ignition sensing and control circuit 100 includes: capacitors C1, C2, C3, and C4; resistors R1, R2, R3, R4, R5, R6, and R7; diodes D1, D2, D3, and D4; and a P-channel MOSFET Q1A (e.g., the channel of which is composed primarily of holes as charge carriers) and an N-channel MOSFET Q2A (e.g., the channel of which is composed primarily of electrons as charge carriers). The ignition sensing and control circuit 100 is electrically coupled to the vehicle's battery power supply line (e.g., a 12V battery power supply line) at a battery power input 100e and receives an ignition input signal 100a from an ignition switch activated by the user to start / stop the vehicle.

[0015] During operation, when the ignition input signal 100a is on (voltage > Von), it powers the ECU by providing a signal at the enable signal 100b to power on the ECU's internal main power supply (or to power on the ECU's microprocessor). Therefore, unless the ignition input signal 100a is high (on), the ECU's internal main power supply (or the ECU's microprocessor) is off, resulting in less current being drawn through the vehicle's battery power lines. The ignition input signal 100a is also read by the ECU's microprocessor as an analog input ignition sensing signal 100c indicating whether ignition has occurred; when ignition has occurred, the ECU's microprocessor is activated.

[0016] After the ECU's microprocessor starts, the microprocessor keeps the ECU's internal main power supply (or microprocessor) on by setting the ignition latch signal 100d high. Setting the ignition latch signal 100d high turns on the N-channel MOSFET Q2A. Turning on Q2A turns on the P-channel MOSFET Q1A. Therefore, Q2A controls the on / off state of Q1A; for example, when Q2A is on, Q1A is on, and when Q2A is off, Q1A is off. Thus, the ignition latch signal 100d, which controls the on / off state of Q2A, is used to control the on / off state of the ECU's main internal power supply (or to activate / deactivate the ECU's microprocessor).

[0017] Once Q1A conducts, the voltage from the vehicle's battery supply line is used to maintain (or keep the microprocessor of) the ECU's main internal power supply in the ON state by providing a voltage signal at the enable signal 100b. When the ignition is turned off (voltage < Voff), for example, the ignition input signal 100a is turned off, and the ECU's microprocessor is programmed to complete its current tasks (such as storing critical values in the flash memory, etc.), and release the ignition latch signal 100d to a low level, thus providing a safe shutdown of the ECU's main internal power supply (or a safe shutdown of the ECU's microprocessor). Note that Von and Voff are the voltage levels for the ECU to turn on and off, which can be set by choosing appropriate values for resistors R6 and R7.

[0018] Figure 2B Is Figure 2A A block diagram representation of the ignition sensing and control circuit 100, and is capable of being compared with Figure 1 A typical ignition sensing and control circuit 10. In Figure 2B It, the ignition sensing and control circuit 100 includes an ignition signal monitor 110, a latch logic 112, and an enable circuit 114.

[0019] As shown, the circuit 100 provides a function similar to that of the circuit 10; however, while providing this function, the logic gates and operational amplifier IC of the comparator 12 are removed, the diodes and IC of the reference power supply IC 14 are removed, and the diodes and IC of the reference signal IC 15 are removed.

[0020] Figure 3 An illustration of an example of using the ignition sensing and control circuit 100 to control the main internal power supply 202 of the ECU 200 is provided. In the example shown, the vehicle's battery supply line directly supplies power to the ignition sensing and control circuit 100 and the main internal power supply 202 of the ECU 200. The ignition sensing and control circuit 100 receives the ignition input signal 100a and uses the ignition input signal 100a to generate an ignition sensing signal 100c input to the microprocessor 204 of the ECU 200 and an enable signal 100b input to the main internal power supply 202 of the main ECU 200, as described herein with reference to Figure 2A As described. The microprocessor 204 of the ECU 200 is powered by the main internal power supply 202 and generates an ignition latch signal 100d, which is used as described herein with reference to Figure 2A As described.

[0021] Figure 4Illustrations are provided of another example of using ignition sensing and control circuitry 100 to control microprocessor 304 of ECU 300. In the example shown, the vehicle's battery power line directly supplies power to ignition sensing and control circuitry 100 and the main internal power supply 302 of ECU 300. Ignition sensing and control circuitry 100 receives ignition input signal 100a and uses ignition input signal 100a to generate ignition sensing signal 100c input to microprocessor 304 of ECU 300 and enable signal 100b input to microprocessor 304 of main ECU 300, as referenced herein. Figure 2A As described herein, the microprocessor 304 of the ECU 300 is powered by the main internal power supply 302 and generates the ignition latch signal 100d, which is referenced herein. Figure 4 Use as described.

[0022] In light of the foregoing, it is understood that the ignition sensing and control circuit 100 can be used in motor vehicles or non-road motor vehicles to enable or disable the ECU. Using the ignition sensing and control circuit 100 eliminates the logic gates and operational amplifiers of the comparator 12 and the reference ICs 14, 15 of the prior art ignition sensing and control circuit 10, thereby reducing cost and PCB space for applications concerned with cost and space.

[0023] The ignition sensing and control circuit 100 specifies that when the ignition input signal 100a is on, the ECU will be powered on, and when the ignition input signal 100a is off, the ECU will draw a minimum current (e.g., less than 10mA) from the battery power supply line. The ignition input signal 100a can be read by the ECU's microprocessor as an analog input enabled at the ignition sensing signal 100c. In response to the ignition sensing signal 100c, the ECU's microprocessor can either keep the ECU's main internal power supply on or start the microprocessor by setting the ignition latch signal 100d to on. When the ignition sensing signal 100c is off, the ECU's microprocessor can complete its current task and release the ignition latch signal 100d to safely shut down the ECU's main internal power supply or safely shut down the microprocessor. Note that the ignition sensing and control circuit 100 includes protection against load dumping, overvoltage, or reverse voltage at the ignition input signal 100a using a transient protection diode D1. The use of MOSFETs and diodes in the ignition sensing and control circuit 100 allows the circuit to be compact (e.g., occupying minimal space on a printed circuit board (PCB)) and low-cost, which is especially useful in designs where PCB space and cost are important considerations.

[0024] The various embodiments described above are provided by way of illustration only and should not be construed as limiting the appended claims. Those skilled in the art will readily recognize that various modifications and changes can be made without following the exemplary embodiments and applications shown and described herein and without departing from the true spirit and scope of the following claims.

Claims

1. An ignition sensing and control circuit for a motor vehicle, comprising: A printed circuit board (PCB) supporting circuitry including first and second MOSFETs powered by the battery power lines of a motor vehicle. The circuit receives an ignition input signal indicating the ignition status of the motor vehicle; In response to the ignition input signal indicating an on state, the first and second MOSFETs enable the voltage from the battery power supply line to latch the main internal power supply of the vehicle's electronic control unit (ECU) into an on state using a latch, thereby controlling the on / off state of the ECU. The ignition input signal is read by the microprocessor of the ECU as an analog input indicating that ignition has occurred, thereby activating the microprocessor. The microprocessor uses a latch to keep the main internal power supply in the ON state. Specifically, by latching the main internal power supply of the ECU into the on state, one of the first and second MOSFETs is turned on, thereby turning on the other of the first and second MOSFETs. When one of the first and second MOSFETs is turned on, the main internal power supply of the ECU is kept in the on state using the voltage from the battery power supply line.

2. The ignition sensing and control circuit as described in claim 1, wherein, One of the first and second MOSFETs includes an N-channel MOSFET, and the other of the first and second MOSFETs includes a P-channel MOSFET.

3. The ignition sensing and control circuit as described in claim 1, wherein, The circuit receives an ignition input signal indicating the off state of the vehicle, causing the latch to release and the main internal power supply of the ECU to be turned off.

4. An ignition sensing and control circuit for a motor vehicle, comprising: A printed circuit board (PCB) supporting circuitry including first and second MOSFETs powered by the battery power lines of a motor vehicle. The circuit receives an ignition input signal indicating the ignition status of the motor vehicle; In response to the ignition input signal indicating an on state, the first and second MOSFETs enable the voltage from the battery power supply line to latch the microprocessor of the vehicle's electronic control unit (ECU) into an on state using a latch, thereby controlling the on / off state of the ECU's microprocessor. The ignition input signal is read by the microprocessor of the ECU as an analog input indicating that ignition has occurred, thereby activating the microprocessor. The microprocessor uses a latch to keep its internal main power supply in the ON state. Specifically, latching the ECU's microprocessor into the ON state causes one of the first and second MOSFETs to conduct, thereby causing the other of the first and second MOSFETs to conduct as well. When one of the first and second MOSFETs is turned on, the microprocessor of the ECU maintains the on state using the voltage from the battery power supply line.

5. The ignition sensing and control circuit as described in claim 4, wherein, One of the first and second MOSFETs includes an N-channel MOSFET, and the other of the first and second MOSFETs includes a P-channel MOSFET.

6. The ignition sensing and control circuit as described in claim 4, wherein, The circuit receives an ignition input signal indicating the off state of the vehicle, causing the latch to release and the microprocessor of the ECU to shut down.

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