Description:Field of the invention

[0001] The present invention relates to a system for controlling signals in an electronic control module. More specifically, the present invention relates to a system and method for detecting and controlling input signals in an electronic control module of a vehicle.

Background of the invention

[0002] In modern vehicles, electronic control modules (ECMs), are essential for managing a range of user-operated functions, including lighting, signalling, and other body-related electronic features. These modules depend on the input detection to respond to driver commands, such as turning ON headlights or activating turn signals. However, existing input detection and control systems has several limitations that affect their accuracy and reliability, especially in practical, real-world conditions.

[0003] One drawback of conventional systems is their susceptibility to leakage currents caused by environmental factors. Dust, moisture, and humidity can accumulate across switch contacts over time, leading to small but continuous leakage currents even when the switch is in an open position. These unintended currents can be misinterpreted by the ECM as valid switch closures, causing false activations or responses. Current solutions lack effective mechanisms to distinguish between actual user inputs and leakage currents, leading to unreliable performance, particularly in harsh environmental conditions.

[0004] Another issue with existing systems is their inefficient power management. In many conventional mechanisms, the pull-down resistor connected to the input detection circuit remains continuously active. This leads to constant current flow, resulting in unnecessary power dissipation and overheating of the circuit components, especially under high-demand or fluctuating voltage conditions. The continuous power draw not only affects the energy efficiency of the system but also accelerates wear on components, reducing the overall lifespan of the control module.

[0005] Moreover, conventional ECMs lack protection against over-voltage conditions. Voltage fluctuations due to faults or anomalies, such as spikes in battery voltage, can exceed the system's safe operating limits, causing damage to the input detection circuitry and other sensitive components. Without adequate over-voltage protection, existing systems are vulnerable to sudden power surges, leading to compromised performance and increased maintenance costs.

[0006] Therefore, there is a need for a system and method for detecting and controlling input signals in an electronic control module which overcomes one or more drawbacks of the above-mentioned prior art.
Objects of the invention

[0007] The object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module.
[0008] Another object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module that improve the accuracy of input detection by distinguishing between valid user inputs and leakage currents caused by environmental factors, such as dust or moisture.

[0009] Yet another object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module that enable efficient power management within the input detection circuit, reducing unnecessary power dissipation and preventing overheating by selectively controlling current flow.

[0010] A further object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module that offer automatic protection against over-voltage conditions to safeguard the electronic control module from potential damage due to sudden voltage spikes or anomalies.

[0011] An additional object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module that increase the overall reliability and lifespan of the electronic control module by addressing common issues that affect the durability and stability of existing systems in automotive environments.

[0012] One more object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module which is compact and cost-effective design that reduces the need for high-wattage resistors, thus minimizing component costs and saving space within the control module.

[0013] An additional object of the present invention is to provide a system and method for detecting and controlling input signals in an electronic control module that simplify maintenance by reducing the frequency of false signal activations, which can otherwise require diagnostic checks or adjustments in conventional systems.

Summary of the invention

[0014] According to the present invention, a system for detecting and controlling input signals in an electronic control module is provided. The system includes a control unit, a pull-down resistor a switching element and a drive circuit. The control unit is configured to generate a pulse-width modulation (PWM) signal with alternating ON and OFF intervals. The pull-down resistor is connected to at least one switch input. The switch input corresponds to a user-operated control in a vehicle. The pull-down resistor is configured to produce a voltage drop in response to current flowing from the switch input. The switching element is configured to regulate current flow through the pull-down resistor. The switching element is activated and deactivated in response to the PWM signal from the control circuit. The drive circuit is configured to receive the PWM signal from the control circuit and control the operation of the switching element. The control unit is configured to monitor the voltage drop across the pull-down resistor during the ON intervals of the PWM signal to determine whether the current from the switch input corresponds to a leakage current or a normal switch current. The switching element is deactivated during the OFF intervals of the PWM signal to interrupt current flow through the pull-down resistor, thereby reducing power dissipation.

[0015] In an aspect of the invention, during each ON interval of the PWM signal, the control unit activates the switching element to control the flow of current through the pull-down resistor and measure the voltage drop across the pull-down resistor to determine the state of each switch input. The monitored voltage drop is compared to a threshold value which is determined or adjusted based on the sensed battery voltage, wherein the voltage drop below the threshold is interpreted by the control unit as leakage current indicating an open switch and the voltage drop above the threshold is interpreted by the control unit as a normal switch current indicating a closed switch. In an aspect, the control unit is configured to monitor the battery voltage and dynamically adjust the duty cycle of the PWM signal based on the monitored battery voltage, such that the ON and OFF intervals vary in response to changes in the battery voltage to reduce power dissipation.

[0016] In an aspect, the threshold value is dynamically adjusted by the control unit based on the sensed battery voltage level, wherein the control unit decreases the threshold when the battery voltage is below a predetermined level and increases the threshold when the battery voltage is above the predetermined level.

[0017] In an aspect of the invention, the control unit is configured to selectively enable or disable current flow through the switching element based on the monitored battery voltage level of a battery by using a battery voltage sensing circuit. The control unit, in response to detecting an over-voltage condition, disables the PWM signal, thereby turning off the switching element and preventing current flow through the pull-down resistor.

[0018] In an aspect of the invention, the control unit re-enables the PWM signal to restore current flow through the switching element and resume monitoring of the switch inputs upon determining that the battery voltage level has returned to a predefined safe operating range.

[0019] In an aspect of the invention, the battery voltage sensing circuit is implemented through a hardware-based sensing mechanism or by a communication protocol like CAN.

[0020] In an aspect of the invention, generate the PWM signal at a predefined frequency and a predefined duty cycle, wherein the PWM signal includes an ON interval and an OFF interval based on the predefined duty cycle. In a further aspect, the duty cycle of the PWM signal is dynamically adjustable based on the sensed battery voltage. Specifically, the control unit monitors the voltage level of the battery and modifies the ON and OFF intervals of the PWM signal in response to changes in the battery voltage.

[0021] In an aspect of the invention, a protective element is connected between the input switch and the pull-down resistor. The protective element is configured to prevent reverse current flow and protect the system.

[0022] In an aspect of the invention a protective resistor (90), a capacitor filter and a voltage-limiting diode are connected between the pull-down resistor and the control unit, the protective resistor limits inrush current, the capacitor filter suppresses high-frequency noise, and the voltage-limiting diode prevents excessive voltage from reaching the control unit during operation.

[0023] In an aspect of the invention a voltage-limiting diode is connected between a control circuit voltage input and ground, the voltage-limiting diode being configured to limit excessive voltage and provide over-voltage protection to the system.

[0024] In an aspect of the invention, an electrostatic discharge (ESD) protection component is configured between the switch inputs and the control circuit to suppress transient voltage spikes and to protect the control circuit from electrostatic discharge events

[0025] In an aspect of the invention, a method for detecting and controlling input signals in an electronic control module is provided. Initially, the operation of the system is initiated by turning on a vehicle’s ignition, which activates a control unit to begin input signal monitoring. After that a pulse-width modulation (PWM) signal with alternating ON and OFF intervals is generated using the control unit. Further, monitoring the voltage level of a battery using a battery voltage sensing circuit and transmitting the sensed voltage to the control unit. The duty cycle of the PWM signal is dynamically adjusted based on the sensed battery voltage, such that the ON and OFF intervals are varied to reduce power dissipation. The pull-down resistor is then connected to one or more switch inputs, each corresponding to a user-operated control in a vehicle, wherein the pull-down resistor is configured to produce a voltage drop in response to the current flowing from the switch inputs.

[0026] The method further includes providing a switching element controlled by a drive circuit, wherein the drive circuit is configured to receive the PWM signal from the control circuit and regulate current flow through the pull-down resistor. During each ON interval of the PWM signal, the switching element is activated, allowing current to flow through the pull-down resistor. The control unit monitors the voltage drop across the pull-down resistor during these ON intervals to determine whether the current from the switch input corresponds to a leakage current or a normal switch current.

[0027] The method continues by comparing the measured voltage drop to a dynamically adjusted threshold value determined from the sensed battery voltage to identify the state of the switch input. A voltage drop below the threshold is interpreted as a leakage current, indicating an open switch, while a voltage drop above the threshold is interpreted as a normal current, indicating a closed switch. Based on this assessment, the input signal is processed by ignoring voltage drops below the threshold as false inputs and treating voltage drops above the threshold as valid inputs, allowing the system to take appropriate actions based on a valid switch closure. In each OFF interval of the PWM signal, the switching element is deactivated to interrupt current flow through the pull-down resistor, thereby reducing power dissipation. Finally, the PWM signal with alternating ON and OFF intervals is repeated to maintain continuous monitoring of the switch inputs.

[0028] In a further aspect of the invention, the current flow through the switching element based on a monitored voltage level of a battery using a battery voltage sensing circuit is selectively enabled or disabled by implementing preventive measures in the control algorithm. Upon detecting an over-voltage condition, the control unit disables the PWM signal to deactivate the switching element and prevent current flow through the pull-down resistor. When the battery voltage level returns to a predefined safe operating range, the PWM signal is re-enabled, thereby restoring current flow through the switching element and resuming monitoring of the switch inputs.

Brief Description of drawings

[0029] The advantages and features of the present invention will be understood better with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which:

[0030] Figure 1 illustrates the circuit diagram of a system for detecting and controlling input signals in an electronic control module in accordance with the present invention;

[0031] Figure 2 illustrates the circuit diagram of a system for detecting and controlling input signals in an electronic control module for controlling multiple switch inputs in accordance with the present invention; and

[0032] Figure 3 illustrates the method for detecting and controlling input signals in an electronic control module in accordance with the present invention.

Detailed description of the invention

[0033] An embodiment of this invention, illustrating its features, will now be described in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0034] The present invention relates to a system for detecting input signals. More specifically, the present invention relates to a system for detecting and controlling input signals in an electronic control module in a vehicle that differentiates between intentional user inputs and minor leakage currents due to environmental factors, while also providing automatic protection against over-voltage conditions ensuring reliable operation in automotive environments.

[0035] The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.

[0036] The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms.

[0037] Referring now to Figure 1, a system (100) for detecting and controlling input signals in an electronic control module is provided. The system (100) includes components distributed between the vehicle side (1) and the electronic control unit (ECU) (2). The components in the vehicle side (1) includes at least one switch input (10), which corresponds to a user-operated control such as a turn signal, high beam, hazard light, or brake light. The switch input (10) is connected to a battery (15) that provides power for the operation of the system. The electronic control unit (ECU) (2) includes a control unit (50), a pull-down resistor (40), a switching element (20), a drive circuit (45), a battery voltage sensing circuit (55) and a control circuit voltage input (65). The system (100) is configured to regulate the current flow through the pull-down resistor (40) to distinguish between valid switch activations and leakage currents, thereby improving the accuracy of input detection and minimizing power dissipation.

[0038] A protective component (60) is connected between the switch input (10) and the pull-down resistor (40). The protective component (60) is configured to block the reverse voltage thereby protecting the system (100). In the present invention, the protective component is a Schottky diode configured to protect the circuit from voltage spikes originating from the switch input (10). It may be obvious to a person skilled in the art to use any other diodes or variations as the protective component (60), such as Zener diodes, transient voltage suppression (TVS) diodes, or any other semiconductor devices based on specific circuit requirements and application constraints.

[0039] Further the system (100) includes a protective resistor (90), a capacitor filter (80) and a first voltage-limiting diode (70a) connected between the pull-down resistor (40) and the control unit (50). Specifically, the protective resistor (90) is connected in series. The protective resistor (90) limits inrush current and the capacitor filter (85) suppresses high-frequency noise in the system (100). The first voltage-limiting diode (70a) prevents excessive voltage from reaching the control unit (50) during operation. Furthermore, the system (100) includes a second voltage-limiting diode (70b) connected between a control circuit voltage input (65) associated with the control unit (50) and the ground (not shown). The second voltage-limiting diode (70b) is configured to limit excessive voltage and provide over-voltage protection to the system (100). In the present invention the voltage-limiting diodes (70a,70b) is a Zener diode.

[0040] The control unit (50) is configured to generate a pulse-width modulation (PWM) signal with alternating ON and OFF intervals. Specifically, the PWM signal is generated at a predefined frequency and duty cycle, where the ON interval is significantly shorter than the OFF interval.

[0041] In one embodiment, the control unit (50) is configured to dynamically adjust the duty cycle of the PWM signal based on the voltage level of the battery (12) monitored by the battery voltage sensing circuit (55). The control unit (50) modifies the ON and OFF intervals of the PWM signal to adapt to variations in battery voltage to reduce power dissipation.

[0042] The pull-down resistor (40) is connected to at least one switch input (10). The switch input (10) corresponds to a user-operated control in a vehicle. Specifically, the switch input (10) refers to user-operated controls in the two-wheeler, such as high beam, turn signals, brake light, hazard light, and pass light switches.

[0043] The pull-down resistor (40) is configured to produce a voltage drop in response to current flowing from the switch input (10). More specifically, during each ON interval of the PWM signal, the control unit (50) samples the voltage drop across the pull-down resistor (40). In cases where the switch input (10) remains open or not engaged by the user, the control unit (50) detect a small current flow due to environmental leakage caused by factors like dust or moisture buildup. The leakage current is generally low, resulting in a small voltage drop across the pull-down resistor (40). Similarly, if the user closes the switch input (10) or engage a turn signal in a vehicle, a significantly larger current flows through the pull-down resistor (40), creating a higher voltage drop. Thus, the control unit (50) monitors the voltage drop across the pull-down resistor (50) during the ON intervals of the PWM signal to determine whether the current from the switch input (10) corresponds to a leakage current or a normal switch current.

[0044] Further the switching element (20) is configured to regulate current flow through the pull-down resistor (40). The switching element (20) is activated and deactivated in response to the PWM signal from the control unit (50). Specifically, the switching element (20) regulates current flow through the pull-down resistor (40) based on control signals received from the drive circuit (45) wherein the drive circuit (45) receive the PWM signal from the control unit (50) and control the operation of the switching element (20). The drive circuit (45) control the operation of the switching element (20) by enabling or disabling current flow through the pull-down resistor (40) in response to the ON and OFF intervals of the PWM signal. The switching element (20) is placed in series with the pull-down resistor (40), thereby allowing the control unit (50) to manage the activation of the pull-down resistor. The switching element only permits current flow through the pull-down resistor (40) when activated by the drive circuit (45), thereby providing a controlled operation of the input detection system.

[0045] During each ON interval of the PWM signal, the control unit (50) activates the switching element (20) through the drive circuit (45) allowing the current to flow through the pull-down resistor (40). Simultaneously, the control unit (50) measures the voltage drop across the pull-down resistor (40) to determine whether the detected current corresponds to leakage current or a normal switch current. If the monitored voltage drop is below a threshold value which is determined or adjusted based on the sensed battery voltage, the control unit (50) interprets this as leakage current, indicating that the switch input is open due to environmental factors such as dust or moisture. If the monitored voltage drop exceeds the threshold value, the control unit (50) interprets this as normal switch current, indicating a valid switch closure by the user. In the present embodiment, the threshold voltage used by the control unit (50) to evaluate the voltage drop across the pull-down resistor (40) is dynamically determined based on the sensed battery voltage. The control unit (50) adjusts the threshold value to ensure input detection under varying voltage conditions. For example, when the battery voltage is below a predetermined level, the threshold value is reduced to allow the system (100) to detect even small voltage drops due to valid switch closures. If the battery voltage rises above a predetermined level, the control unit (50) increases the threshold to avoid misinterpreting minor leakage currents as valid switch closures.
[0046] During each OFF interval of the PWM signal, the switching element (20) is deactivated, interrupting current flow through the pull-down resistor (40) to reduce power dissipation and prevent overheating. Further, the system (100) includes a battery voltage sensing circuit (55) configured to monitor the voltage level of the battery (12) and communicate the voltage level to the control unit (50). The battery voltage sensing circuit (55) can be implemented through hardware-based sensing or via a communication protocol. If the battery voltage exceeds a predefined safe operating range, the control unit (50) disables the PWM signal thereby turning off the switching element (20) and preventing current flow through the pull-down resistor (40). Once the battery voltage returns to a predefined safe level, the control unit (50) re-enables the PWM signal restoring normal operation of the input detection system.

[0047] Furthermore, the system (100) includes an electrostatic discharge (ESD) protection component (80), configured between the switch inputs (10) and the control unit (50) to suppress transient voltage spikes and protects the control unit (50) from electrostatic discharge events.

[0048] Referring now to Figure 2, a system (100) for processing multiple switch inputs (10) (Referred as D1 to Dn) and monitoring battery voltage levels. Each switch input (10) is linked to a corresponding processing circuit (35) that represents multiple switching elements (C1 to Cn), which transmits signals to the control unit (50) for decision-making. The control unit (50) regulates current flow through the drive circuit (45), providing proper operation and protection against voltage fluctuations.

[0049] In an embodiment, the switching element (20) includes a first transistor (not shown in Figure) and a second transistor (not shown in figure) to regulate the current flow through the pull-down resistor (40). Specifically, the first transistor is configured to receive the PWM signal from the control unit (50), and the second transistor is responsible for controlling the current flow through the pull-down resistor (40) based on the switching action of the first transistor. The first transistor functions as a control switch for the second transistor thereby enabling or disabling the second transistor based on the ON and OFF intervals of the PWM signal.

[0050] For example, during the ON interval of the PWM signal, the control unit (50) activates the first transistor, which in turn enables the second transistor allowing the current to flow through the pull-down resistor (40). The current flow results in a voltage drop across the pull-down resistor (40), which is measured by the control unit (50) to determine whether the input corresponds to leakage current or a valid switch closure. If the detected voltage drop is below a threshold value which is determined or adjusted based on the sensed battery voltage, it is interpreted as leakage current, indicating an open switch. If the voltage drop exceeds the threshold, it is interpreted as a normal switch current, indicating that the switch is closed.

[0051] Similarly, during the OFF interval of the PWM signal, the control unit (50) deactivates the first transistor, which in turn disables the second transistor, interrupting current flow through the pull-down resistor (40). By integrating the first and second transistors in series with the pull-down resistor (40), the system (100) provides control over current flow such that the pull-down resistor (40) is only active when required leading to improved power efficiency and input detection accuracy.

[0052] Further the control unit (50) is configured to implement preventive measures within the control algorithm to selectively enable or disable current flow through the switching element (20) based on the monitored voltage level of the battery (12). Specifically, the control unit (50) in response to detecting an over-voltage condition, disables the PWM signal thereby turning off the switching element and prevent the current flow through the pull-down resistor (40).
[0053] In the present embodiment, the system (100) detects the over voltage condition using a battery voltage sensing circuit (55). Specifically, the battery voltage sensing circuit (55) continuously monitors the battery voltage level and transmits the data to the control unit (50). The battery voltage sensing circuit (55) may function through a hardware-based voltage monitoring or through a communication protocol to receive real-time voltage data.

[0054] Further upon detecting the over-voltage condition the control unit (50) immediately recognizes that the voltage level has surpassed the safe threshold. For example, when the system (100) reads a voltage of approximate 17V above the safe limit of 16V, the control unit (50) responds by blocking the PWM signal sent to the drive circuit (45) thereby disabling the operation of the switching element (20). As a result, the switching element (20) remains OFF continuously, preventing any current flow through the pull-down resistor (40). With the circuit path open, no voltage drop occurs across the pull-down resistor (40), thereby eliminating unnecessary power dissipation and protecting the components of the system (100) from overheating.

[0055] The control unit (50) re-enables the PWM signal to restore current flow through the switching element (20) and resume the monitoring of the switch inputs (10) upon determining that the battery (35) voltage level has returned to a predefined safe operating range.

[0056] Referring now to Figure 2, a method (200) for detecting and controlling input signals in an electronic control module in a vehicle is provided.

[0057] The method (200) starts at step 210.

[0058] At step 220, the operation of the system (100) is initiated by turning on a vehicle’s ignition and activating a control unit (50) to begin input signal monitoring. Specifically, when the vehicle’s ignition is turned on, the system (100) is activated and the control unit begins to monitor input signals from various switch inputs (10) which are user-operated controls within the vehicle. The initial activation sets the system (100) into a monitoring mode allowing to detect switch input (10) states and to differentiate between valid inputs and environmental interference.

[0059] At step 230, a pulse-width modulation (PWM) signal is generated with alternating ON and OFF intervals using the control unit (50). The alternating ON and OFF intervals allow the control unit (50) to intermittently sample the input signals during the ON periods while letting the system (100) cool down during the OFF periods there by preventing overheating.

[0060] At step 240, a pull-down resistor (40) is connected to one or more switch inputs (10). Each switch input (10) corresponds to a user-operated control in a vehicle. The pull-down resistor (40) is configured to produce a voltage drop in response to the current flowing from the one or more switch inputs (10). The user-operated control in the vehicle includes turn signal, high beam, hazard light, or brake light. When a switch input (10) is engaged by the user, the current flows from the switch input (10) through the pull-down resistor (40) creating a measurable voltage drop across the pull-down resistor (40). The voltage drop is proportional to the current flowing through the switch input (10), and the value of the voltage drop indicates whether the switch is open indicating a leakage current or closed indicating a valid current. For example, if the left turn signal is engaged, current will flow through the pull-down resistor (40), producing a distinct voltage drop that the control unit (50) can measure.

[0061] At step 250, a switching element (20) is configured to regulate current flow through the pull-down resistor (40). The switching element (20) receives the PWM signal from the control unit (50) through the drive circuit (45).
[0062] At step 260, the switching element (20) is activated during each ON interval of the PWM signal. Specifically, during each ON interval, the drive circuit (45) enables the switching element (20), to allow current flow through the pull-down resistor (40). The alternating ON and OFF activation of the switching element (20) provides a sampling mechanism providing accurate signal detection.

[0063] At step 270, the voltage drop across the pull-down resistor (40) is monitored during the ON intervals of the PWM signal to determine whether the current from the switch input (10) corresponds to a leakage current or a normal switch current. Specifically, during the ON intervals, the control unit (50) continuously monitors the voltage drop across the pull-down resistor (40). This voltage drop reflects the state of the switch input (10), indicating either a leakage current due to environmental factors or a valid switch closure by the user. For example, a small leakage current caused by environmental factors such as dust or moisture across the switch contacts, will result in a low voltage drop. In contrast, when the switch is fully closed by the user, a higher current flows, creating a larger voltage drop across the pull-down resistor (40). The control unit monitors the voltage level of the battery through the battery voltage sensing circuit and dynamically adjusts the duty cycle of the PWM signal accordingly. For example, if the battery voltage exceeds the threshold value, the ON interval of the PWM signal is reduced and the OFF interval is extended to reduce power dissipation. Similarly, if the battery voltage is below the threshold, the ON interval may be extended to ensure adequate signal detection.

[0064] At step 280, the measured voltage drop is compared to a threshold value to identify the state of the switch input (10), wherein a voltage drop below the threshold is interpreted as a leakage current indicating an open switch and the voltage drop above the threshold is interpreted as a normal switch current indicating a closed switch. The control unit adjusts the threshold value used for comparison of the measured voltage drop based on the sensed battery voltage. For instance, if the battery voltage is low, the control unit reduces the comparison threshold. If the battery voltage is high, it increases the threshold to avoid false detection from leakage currents.

[0065] At step 290, the input signal is processed by ignoring the voltage drops below the threshold as false inputs and treating the voltage drops above the threshold as valid inputs and taking appropriate actions based on the valid switch closure. Specifically for voltage drops below the threshold, the control unit (50) disregards the input as a false signal caused by environmental leakage current. However, if the voltage drop is above the threshold the control unit (50) treats it as a valid input and activates the associated vehicle function. For example, a valid input from the left turn signal switch would trigger the left turn indicator light, signalling the user’s intended action.

[0066] At step 300, the switching element (20) is deactivated during each OFF interval of the PWM signal to interrupt current flow through the pull-down resistor (40) thereby reducing power dissipation. Specifically, during each OFF interval of the PWM signal, the control unit (50) turns OFF the drive circuit (45), which disables the switching element. This action interrupts the current flow through the pull-down resistor (40), allowing the pull-down resistor (40) to cool and prevent continuous power dissipation. By controlling the ON and OFF intervals, the system (100) utilizes energy only when needed which in turn increases the lifespan of the pull-down resistor (40) and other components.

[0067] At step 310, the pulse-width modulation (PWM) signal with alternating ON and OFF intervals are repeated to maintain the monitoring of the switch inputs (10).

[0068] The method (200) ends at step 320.

[0069] The method (200) further comprises steps of implementing preventive measures in the control algorithm to selectively enable or disable current flow through the switching element (20) based on the voltage level of the battery using a battery voltage sensing circuit (55). The battery voltage sensing circuit (55) is configured to continuously monitor the battery voltage level and communicate the detected voltage to the control unit (50). Specifically, upon detecting an over-voltage condition the control unit (50) disables the PWM signal to deactivate the switching element (20) and prevent current flow through the pull-down resistor (40). More specifically if an over-voltage condition is detected, the control unit (50) blocks the PWM signal thereby turning off the switching element (20) and prevent the current flow through the pull-down resistor (40).

[0070] The PWM signal is re-enabled when the voltage level of the battery (15) returns to a predefined safe operating range, thereby restoring current flow through the switching element (20) and resuming monitoring of the switch inputs (10).

[0071] Thus, the present invention has the advantage of providing a system and method for detecting and controlling input signals in an electronic control module, specifically designed to enhance accuracy, efficiency, and reliability in vehicle applications. The invention improves input detection accuracy by distinguishing between valid user inputs and leakage currents caused by environmental factors, such as dust or moisture. It further enables efficient power management within the input detection circuit by selectively controlling current flow, thereby reducing unnecessary power dissipation and preventing overheating. Additionally, the system offers automatic protection against over-voltage conditions, safeguarding the electronic control module from potential damage due to sudden voltage spikes or anomalies.

[0072] The present invention also increases the overall reliability and lifespan of the electronic control module by addressing common issues that compromise durability and stability in automotive environments. Furthermore, the system provides a compact and cost-effective design that minimizes the need for high-wattage resistors, reducing component costs and saving space within the control module. Finally, by reducing the frequency of false signal activations, the invention simplifies maintenance, lowering the need for diagnostic checks or adjustments that are often required in conventional systems.

[0073] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
, Claims:1. A system (100) for detecting and controlling input signals in an electronic control module the system (100) comprising:
a control unit (50) configured to generate a pulse-width modulation (PWM) signal with predefined frequency and duty cycle;
a pull-down resistor (40) connected to at least one switch input (10), the switch input (10) corresponds to a user-operated control in a vehicle and the pull-down resistor (40) is configured to produce a voltage drop in response to the current flowing from the switch inputs (10), characterized in that the system (100) comprises:
a switching element (20) configured to regulate the current flow through the pull-down resistor (40);
a drive circuit (45) configured to receive the PWM signal from the control unit (50) and control the operation of the switching element (20); and
a battery voltage sensing circuit (55) for monitoring the voltage level of the battery (12) and communicate the voltage level to the control unit (50),
wherein the switching element (20) is controlled based on the PWM signal from the control unit (50) such that the switching element (20) is activated to allow current flow through the pull-down resistor (40) during the ON intervals of the PWM signal and deactivated during the OFF intervals of the PWM signal to interrupt current flow through the pull-down resistor (40) thereby reducing power dissipation.

2. The system (100) as claimed in claim 1wherein the control unit (50) is configured to monitor the voltage drop across the pull-down resistor (40) during the ON intervals of the PWM signal to determine whether the current from the switch input (10) corresponds to a leakage current or a normal switch current.

3. The system (100) as claimed in claim 1, wherein during each ON interval of the PWM signal, the control unit (50) activates the switching element (20) to control the flow of current through the pull-down resistor (40) and measure the voltage drop across the pull-down resistor (40) to determine the state of each switch input (10) and the monitored voltage drop is compared to a threshold value which is determined or adjusted based on the sensed battery voltage, wherein the voltage drop below the threshold is interpreted by the control unit (50) as the leakage current indicating an open switch and the voltage drop above the threshold is interpreted by the control unit (50) as a normal switch current indicating a closed switch.

4. The system (100) as claimed in claim 1, wherein the control unit (50) is configured to selectively enable or disable current flow through the switching element (20) based on the monitored battery voltage level using the battery voltage sensing circuit (55) wherein the control unit (50), in response to detecting an over-voltage condition disable the PWM signal thereby turning OFF the switching element (20) and prevent the current flow through the pull-down resistor (40).

5. The system (100) as claimed in claim 1, wherein the control unit (50) re-enables the PWM signal to restore current flow through the switching element (20) and resume the monitoring of the switch inputs (10) upon determining that the voltage level of battery has returned to a predefined safe operating range.

6. The system (100) as claimed in claim 1, wherein the control unit (50) is configured to monitor the battery voltage and dynamically adjust the duty cycle of the PWM signal based on the monitored battery voltage, such that the ON and OFF intervals vary in response to changes in the battery voltage to reduce power dissipation.

7. The system (100) as claimed in claim 3, wherein the threshold value is dynamically adjusted by the control unit (50) based on the sensed battery voltage level, wherein the control unit decreases the threshold when the battery voltage is below a predetermined level and increases the threshold when the battery voltage is above the predetermined level.
8. The system (100) as claimed in claim 1, wherein the battery voltage sensing circuit (55) is implemented through a hardware-based sensing mechanism or by a communication protocol.

9. The system (100) as claimed in claim 1, wherein the control unit (50) is configured to generate the PWM signal at a predefined frequency and a predefined duty cycle, wherein the PWM signal includes an ON interval and an OFF interval based on the predefined duty cycle. The system (100) as claimed in claim 1, wherein a protective element (60) is connected between the input switch (10) and the pull-down resistor (40), the protective element (60) being configured to prevent reverse current flow and protect the system (100) from reverse polarity.

10. The system (100) as claimed in claim 1, wherein a protective resistor (90), a capacitor filter (85), and a first voltage-limiting diode (70a) are connected between the pull-down resistor (40) and the control unit (50), the protective resistor (90) limits inrush current, the capacitor filter (80) suppresses noise, and the first voltage-limiting diode (70a) prevents excessive voltage from reaching the control unit (50) during operation.

11. The system (100) as claimed in claim 1, wherein a second voltage-limiting diode (70b) is connected between a control circuit voltage input (65) and the control unit (50) the second voltage-limiting diode (70b) being configured to limit excessive voltage and provide over-voltage protection to the control unit (50).

12. The system (100) as claimed in claim 1, wherein multiple switch inputs (10) are sensed by corresponding processing circuit (35), each switching elements ((C1 to Cn)) in the processing circuit (35) being configured to detect the state of a respective switch input (10) wherein the switching elements (C1 to Cn) are driven by a single drive circuit (45).

13. The system (100) as claimed in claim 1, wherein an electrostatic discharge (ESD) protection component (80) is configured between the switch inputs (10) and the control circuit (50) to suppress transient voltage spikes and to protect the control circuit (50) from electrostatic discharge events.

14. A method (200) for detecting and controlling input signals in an electronic control module (300), the method (200) comprising steps of:
initiating the operation of the system (100) by turning ON a vehicle’s ignition and activating a control unit (50) to begin input signal monitoring;
generating a pulse-width modulation (PWM) signal with alternating ON and OFF intervals using the control unit (50);
monitoring the voltage level of a battery (12) using a battery voltage sensing circuit (55) and transmitting the sensed voltage to the control unit (50);
adjusting the duty cycle of the PWM signal dynamically based on the sensed battery voltage, such that the ON and OFF intervals are varied to reduce power dissipation;
connecting a pull-down resistor (40) to one or more switch inputs (10), each switch input (10) corresponds to a user-operated control in a vehicle, wherein the pull-down resistor (40) is configured to produce a voltage drop in response to the current flowing from the one or more switch inputs (10);
providing a switching element (20) controlled by a drive circuit (45), wherein the drive circuit is configured to receive the PWM signal from the control unit (50) and regulate current flow through the pull-down resistor (40);
activating the switching element (20) during each ON interval of the PWM signal;
monitoring the voltage drop across the pull-down resistor (40) during the ON intervals of the PWM signal to determine whether the current from the switch input (10) corresponds to a leakage current or a normal switch current;
dynamically adjusting a threshold value based on the sensed battery voltage;
comparing the measured voltage drop to the dynamically adjusted threshold value, to identify the state of the switch input (10), wherein a voltage drop below the threshold value is interpreted as a leakage current indicating an open switch and the voltage drop above the threshold is interpreted as a normal switch current indicating a closed switch;
processing the input signal by ignoring the voltage drops below the threshold as false inputs and treating the voltage drops above the threshold as valid inputs and taking appropriate actions based on the normal switch current;
deactivating the switching element (20) during each OFF interval of the PWM signal to interrupt current flow through the pull-down resistor (40), thereby reducing power dissipation; and
repeating the pulse-width modulation (PWM) signal (55) with alternating ON and OFF intervals to maintain the monitoring of the switch inputs (10).

15. The method (200) as claimed in claim 11, further comprising the steps of:
implementing preventive measures in the control algorithm to selectively enable or disable the current flow through the switching element (20) based on a monitored voltage level of a battery (12) using a battery voltage sensing circuit (55), wherein the battery voltage sensing circuit (55) is configured to continuously monitor the battery voltage level and communicate the detected voltage to the control unit (50), and upon detecting an over-voltage condition, the control unit (50) disables the PWM signal to deactivate the switching element (20) and prevent the current flow through the pull-down resistor (40); and
re-enabling the PWM signal when the voltage level of the battery (12) returns to a predefined safe operating range, thereby restoring current flow through the switching element (20) and resuming monitoring of the switch inputs (10).