Ignition module circuit that prevents comparator negative voltage turn-on

Abstract

This invention relates to an ignition module circuit for preventing comparator conduction under negative voltage. Diode D2 is connected in series between an RC charging / discharging circuit and a comparator U1B. The anode of diode D2 is connected to the RC charging / discharging circuit, and the cathode of diode D2 is connected to the non-inverting input U1B_5 of comparator U1B via a series resistor R8. Simultaneously, the cathode of diode D2 is connected to the other end of resistor R12 to form a negative voltage protection circuit. Diode D2 and resistor R12 are connected in series to form the discharge circuit for capacitors C1 and C3. The other ends of resistors R1 and R2 are both connected to the inverting input U1B_6 of comparator U1B, and resistors R1 and R2 are connected in series to divide the voltage. The RC charging / discharging circuit receives the input signal S1, the negative voltage protection circuit processes the input signal, comparator U1B compares the voltages at both ends, and comparator U1B outputs signal S2 at its output terminal U1B_7. This invention prevents ignition coil misfires due to negative voltage interference, reducing the risk of various vehicle malfunctions caused by ignition coil misfires.

Description

Technical Field

[0001] This invention relates to an electronic ignition control system for automotive engines, specifically an ignition module circuit that prevents comparator conduction due to negative pressure. Background Technology

[0002] Currently, most ignition modules used in automotive control systems employ comparators. Multi-stage comparators are used to identify and process signals output by the ECU and to implement complex ignition module functions. The signal input of the comparator is compared with a set reference voltage to output different signals. The output signal controls the power transistor to achieve the ignition coil ignition function.

[0003] Currently, mainstream ignition modules use comparators to process input signals and control the output. However, this approach fails to account for the impact of negative voltages exceeding the comparator's specifications, resulting in the following drawbacks:

[0004] The input signal of a comparator may have a negative voltage. The most typical example is an RC circuit. The capacitor in the RC circuit will charge and discharge, generating positive and negative voltages. If the input signal of the comparator is not processed, a negative voltage may enter the comparator. When the generated negative voltage is large and exceeds the normal operating range of the comparator, the comparator will have a logic error and mistakenly output a high level to drive the power transistor. This can lead to phenomena such as false ignition and ignition delay, which can easily cause other malfunctions in the car. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an ignition module circuit that prevents comparator negative pressure conduction by reducing ignition coil misfires caused by negative pressure and lowering the risk of various vehicle malfunctions resulting from ignition coil misfires.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: an ignition module circuit for preventing comparator negative voltage conduction, including comparator U1B, diode D2, capacitor C1, capacitor C3, resistor R1, resistor R2, resistor R3, resistor R5, resistor R7, resistor R8 and resistor R12, wherein the comparator U1B includes a non-inverting input terminal U1B_5, an inverting input terminal U1B_6 and an output terminal U1B_7, and a comparison reference voltage is provided at the inverting input terminal U1B_6;

[0007] One end of each of resistors R1, R3 and R5 is connected to the corresponding power supply terminal, and one end of each of resistors R2, R7 and R12 is grounded.

[0008] The resistors R5 and R7 are connected in series, and capacitors C1 and C3 are connected in parallel between the resistors R5 and R7. The parallel connection of capacitors C1 and C3, together with the series connection of resistor R7, forms an RC charging and discharging circuit.

[0009] The diode D2 is connected in series between the RC charging and discharging circuit and the comparator U1B. The positive terminal of the diode D2 is connected to the RC charging and discharging circuit, and the negative terminal of the diode D2 is connected to the non-inverting input terminal U1B_5 of the comparator U1B through the series resistor R8. At the same time, the negative terminal of the diode D2 is connected to the other end of the resistor R12 to form a negative voltage protection circuit. The diode D2 and the resistor R12 are connected in series to form the discharge circuit of the capacitor C1 and the capacitor C3. The other ends of the resistors R1 and R2 are both connected to the inverting input terminal U1B_6 of the comparator U1B, and the resistors R1 and R2 are connected in series to divide the voltage.

[0010] The other end of the resistor R3 is connected to the output terminal U1B_7 of the comparator U1B.

[0011] Preferably, the RC charging and discharging circuit receives the input signal S1, the negative pressure protection circuit processes the input signal, and the comparator U1B output terminal U1B_7 outputs the signal S2.

[0012] Preferably, resistor R5 is a pull-up resistor for the output of the preamplifier U1B; resistor R3 is a pull-up resistor for the inverting input U1B_7 of comparator U1B.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention prevents the power transistor from mis-conducting due to negative voltage caused by various factors in the comparator circuit, which could lead to ignition coil mis-ignition. The ignition control circuit that prevents comparator conduction due to negative voltage can reduce the risk of ignition coil mis-ignition caused by negative voltage, thus lowering the risk of various vehicle malfunctions caused by ignition coil mis-ignition. Attached Figure Description

[0015] Figure 1 This is the signal processing circuit diagram of the present invention;

[0016] Figure 2 This is a flowchart of the signal processing of the present invention. Detailed Implementation

[0017] The following will combine Figure 1-2 The present invention will be described in detail below. The illustrative embodiments and descriptions herein are used to explain the invention, but are not intended to limit the invention.

[0018] An ignition module circuit for preventing comparator conduction under negative voltage includes a comparator U1B, a diode D2, a capacitor C1, a capacitor C3, a resistor R1, a resistor R2, a resistor R3, a resistor R5, a resistor R7, a resistor R8, and a resistor R12. The comparator U1B includes a non-inverting input terminal U1B_5, an inverting input terminal U1B_6, and an output terminal U1B_7. A comparison reference voltage is provided at the inverting input terminal U1B_6.

[0019] One end of resistors R1, R3, and R5 is connected to the corresponding power supply terminal, and one end of resistors R2, R7, and R12 is grounded.

[0020] Resistors R5 and R7 are connected in series, and capacitors C1 and C3 are connected in parallel between resistors R5 and R7. The parallel connection of capacitors C1 and C3, together with resistor R7, forms an RC charging and discharging circuit.

[0021] Diode D2 is connected in series between the RC charging / discharging circuit and comparator U1B. The positive terminal of diode D2 is connected to the RC charging / discharging circuit, and the negative terminal of diode D2 is connected to the non-inverting input terminal U1B_5 of comparator U1B through the series resistor R8. At the same time, the negative terminal of diode D2 is connected to the other end of resistor R12 to form a negative voltage protection circuit. Diode D2 and resistor R12 are connected in series to form the discharge circuit of capacitor C1 and capacitor C3. The other ends of resistors R1 and R2 are both connected to the inverting input terminal U1B_6 of comparator U1B, and resistors R1 and R2 are connected in series to divide the voltage.

[0022] The other end of resistor R3 is connected to the output terminal U1B_7 of comparator U1B.

[0023] The RC charging and discharging circuit receives the input signal S1, the negative voltage protection circuit processes the input signal, and the comparator U1B output terminal U1B_7 outputs the signal S2; resistor R5 is the pull-up resistor of the output of the pre-stage of comparator U1B; resistor R3 is the pull-up resistor of the inverting input terminal U1B_7 of comparator U1B.

[0024] In the implementation process, the principle of voltage comparator applied in actual products is as follows: Figure 1By adjusting the values ​​of resistors and capacitors, time protection and control circuit output functions can be achieved. The basic principle of a comparator is to compare the magnitudes of two input voltages within its operating voltage range. If the voltage at the non-inverting input is greater than the voltage at the inverting input, a high level is output; if the voltage at the non-inverting input is less than the voltage at the inverting input, a low level is output. If the input voltage is a large negative voltage, exceeding the comparator's normal operating range, the comparator input voltage needs to be identified and processed. This can prevent negative voltage interference from causing misfires in the ignition coil, reducing the risk of various vehicle malfunctions caused by misfires. The main principle of the circuit is shown below:

[0025] Figure 1 In this circuit, resistor R5 is the pull-up resistor for the output of the preamplifier U1B; capacitors C1 and C3 are connected in parallel and then in series with resistor R7 to form an RC charging and discharging circuit, used to set the duration of time protection; diode D2 acts as an isolation element to prevent the negative voltage generated by capacitors C1 and C3 from reaching the non-inverting input U1B_5 of comparator U1B; diode D2 and resistor R12 are connected in series to form a negative voltage protection circuit, which also serves as a discharge circuit for capacitors C1 and C3; resistors R1 and R2 are connected in series to divide the voltage, setting the comparison reference voltage at the inverting input U1B_6 of comparator U1B; resistor R3 is the pull-up resistor for the output U1B_7 of comparator U1B.

[0026] When the input signal S1 changes from low to high, capacitors C1 and C3 begin to charge. The voltage levels at the right ends of capacitors C1 and C3 gradually decrease from high to low. This voltage level is input to the non-inverting input U1B_5 of comparator U1B through diode D2 and resistor R8. When the voltage level is higher than the reference voltage set at the inverting input U1B_6 of comparator U1B, comparator U1B_7 outputs a high level, and the ignition coil operates. When the voltage level is lower than the reference voltage set at the inverting input U1B_6 of comparator U1B, comparator U1B_7 outputs a low level, and the ignition coil does not operate.

[0027] When the input signal S1 changes from high to low, capacitors C1 and C3 begin to discharge. Due to the characteristic that the voltage across a capacitor cannot change abruptly, the voltage at the right end of capacitors C1 and C3 will slowly rise from a negative voltage. Without diode D2, the negative voltage could be input to the non-inverting input U1B_5 of comparator U1B, causing a logic error in the comparator. The output U1B_7 of comparator U1B would still output a high level, resulting in a high-level delay until the negative voltage is less than the comparator's specification limit, at which point the comparator logic returns to normal. However, in this circuit, due to the unidirectional conductivity of diode D2, the negative voltage will not be input to the non-inverting input U1B_5 of comparator U1B, allowing the comparator to function normally. The output U1B_7 of comparator U1B outputs a low level, thus avoiding the high-level delay in the output U1B_7 of comparator U1B.

[0028] like Figure 2 As shown, when the input signal S1 flows through the RC charging and discharging circuit, it generates positive or negative voltage respectively. When diode D2 determines that it is positive voltage, the input signal flows through the negative voltage protection circuit again and enters the signal processing comparator U1B. The comparator U1B then compares and judges the input voltage. If the comparator U1B determines that the input voltage is greater than the reference voltage, the ignition coil will work; if the input voltage is less than the reference voltage, the ignition coil will not work. When diode D2 determines that it is negative voltage, the input signal no longer flows into the comparator U1B, and the ignition coil will not work.

[0029] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An ignition module circuit for preventing comparator conduction under negative voltage, characterized in that: The system includes comparator U1B, diode D2, capacitor C1, capacitor C3, resistors R1, R2, R3, R5, R7, R8, and R12. The comparator U1B includes a non-inverting input terminal U1B_5, an inverting input terminal U1B_6, and an output terminal U1B_7. A comparison reference voltage is provided at the inverting input terminal U1B_6. One end of each of resistors R1, R3 and R5 is connected to the corresponding power supply terminal, and one end of each of resistors R2, R7 and R12 is grounded. The resistors R5 and R7 are connected in series, and capacitors C1 and C3 are connected in parallel between the resistors R5 and R7. The parallel connection of capacitors C1 and C3, together with the series connection of resistor R7, forms an RC charging and discharging circuit. The diode D2 is connected in series between the RC charging and discharging circuit and the comparator U1B. The positive terminal of the diode D2 is connected to the RC charging and discharging circuit, and the negative terminal of the diode D2 is connected to the non-inverting input terminal U1B_5 of the comparator U1B through the series resistor R8. At the same time, the negative terminal of the diode D2 is connected to the other end of the resistor R12 to form a negative voltage protection circuit. The diode D2 and the resistor R12 are connected in series to form the discharge circuit of the capacitor C1 and the capacitor C3. The other ends of the resistors R1 and R2 are both connected to the inverting input terminal U1B_6 of the comparator U1B, and the resistors R1 and R2 are connected in series to divide the voltage. The other end of the resistor R3 is connected to the output terminal U1B_7 of the comparator U1B. The RC charging and discharging circuit receives the input signal S1, the negative voltage protection circuit processes the input signal, and the comparator U1B output terminal U1B_7 outputs the signal S2.

2. The ignition module circuit that prevents the comparator from conducting at negative voltages according to claim 1, wherein: The resistor R5 is the pull-up resistor for the output of the preamplifier U1B; the resistor R3 is the pull-up resistor for the inverting input U1B_7 of the comparator U1B.

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