Capacitor charging module, air bag restraint system controller and air bag restraint system

Abstract

The invention provides a capacitor charging module. The capacitor charging module comprises a voltage converter, a voltage dividing module, a current adjusting module and a power supply end comparison module. The voltage dividing module is electrically connected with the output end of the voltage converter so as to obtain a first feedback signal and a second feedback signal which are used for reflecting the output voltage of the voltage converter. The current adjusting module compares the first feedback signal with the first reference signal, increases the charging current of the energy storage capacitor in the charging mode when the first feedback signal is larger than the first reference signal, and enables the charging current of the energy storage capacitor in the charging mode not to be increased when the first feedback signal is smaller than the first reference signal. And the power supply end comparison module receives a second reference signal and outputs a control signal for controlling the output of the charging power supply based on the comparison of the second reference signal and the second feedback signal. An airbag controller and an airbag system are also provided.

Description

TECHNICAL FIELD

[0001] The present application relates to charging technology, more particularly to charging technology for air bag controller in a vehicle. BACKGROUND

[0002] An air bag (AB) control system needs to reserve sufficient energy, i.e. to reserve sufficient energy in an energy reserve capacitor (ER) with a large capacitance value. When designing an air bag controller chipset, it is crucial to set the charging current for the energy reserve capacitor.

[0003] Figure 1 is a schematic diagram of a charging module in an application specific integrated circuit (ASIC) for charging an energy reserve capacitor. As shown in Figure 1 The charging module 2 of the ASIC receives power 10 from a power source, and a boost converter 20 receives the power 10 and converts it into power with a voltage of Vup. The power with the voltage of Vup is transmitted to a current source regulator 22 electrically connected to the energy reserve capacitor ERC, to thereby charge the energy reserve capacitor ERC. During the charging process, the output current of the charging module of the ASIC should be less than its maximum performance current, for example less than the rated current of the boost converter 20. However, in the initial stage of charging, if the charging current of the energy reserve capacitor is large, it can cause the devices of the ASIC to overheat, triggering circuit abnormalities or damage. In the design process of an air bag, for example, the charging current of the energy reserve capacitor is usually limited to a small value to ensure the normal operation of the ASIC charging module, or to ensure the normal operation of the ASIC, but this can result in a long charging time. On the other hand, if the ASIC used changes, the charging current of the energy reserve capacitor ERC has to be re-determined, increasing the workload.

[0004] In view of the above problems, it is urgent to improve the prior art to optimize the charging design of the energy reserve capacitor and improve the performance and reliability of the air bag system SUMMARY

[0005] According to one aspect of the present application, a capacitor charging module is provided, which can include a voltage converter for converting an input voltage to an output voltage; a voltage dividing module electrically connected to an output of the voltage converter to obtain a first feedback signal and a second feedback signal for reflecting the output voltage of the voltage converter; a current regulating module for comparing the first feedback signal with a first reference signal and increasing a charging current of an energy storage capacitor in a charging mode if the first feedback signal is greater than the first reference signal and not increasing the charging current of the energy storage capacitor in the charging mode if the first feedback signal is less than the first reference signal; and a power terminal comparing module for receiving a second reference signal and outputting a control signal for controlling an output of the charging power supply based on a comparison between the second reference signal and the second feedback signal.

[0006] Optionally or exemplarily, in the charging module, the voltage dividing module can include a first voltage dividing unit having an input connected to an output of the charging power supply; a second voltage dividing unit having an input connected to an output of the first voltage dividing unit; a third voltage dividing unit having an input connected to an output of the second voltage dividing unit; the first feedback signal is collected from a connection between the second voltage dividing unit and the third voltage dividing unit, and the second feedback signal is collected from a connection between the first voltage dividing unit and the second voltage dividing unit, and the first voltage dividing unit, the second voltage dividing unit and the third voltage dividing unit are configured such that a voltage represented by the first feedback signal is greater than a voltage represented by the second feedback signal.

[0007] Optionally or exemplarily, in the charging module, the first voltage dividing unit, the second voltage dividing unit and the third voltage dividing unit are resistors.

[0008] Optionally or exemplarily, in the charging module, the current regulating module includes a first comparator having inputs receiving the first feedback signal and the first reference signal, and a driver having an input connected to an output of the first comparator to adjust the charging current according to the output signal.

[0009] Optionally or exemplarily, in the charging module, the first feedback signal is input to a non-inverting input of the first comparator, and the first reference signal is input to an inverting input of the first comparator.

[0010] Optionally or exemplarily, in the charging module, the first feedback signal and the first reference signal are voltage signals or current signals, and the second feedback signal and the first reference signal are voltage signals or current signals.

[0011] Optionally or exemplarily, in the charging module, the voltage converter is a step-up converter.

[0012] Optionally or exemplarily, the first reference signal and the second reference signal are the same.

[0013] Also provided is a safety airbag controller configured with an energy storage capacitor, wherein the safety airbag controller is provided with any one of the charging modules as described above.

[0014] Also provided is a safety airbag system comprising a safety airbag, a gas generator and the safety airbag controller as described herein. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will become more fully understood from the detailed description given herein below, and accompanied by the accompanying drawings, wherein like elements are numbered alike in which:

[0016] Figure 1 is a schematic diagram of a structure of charging an energy storage capacitor by an application specific integrated circuit (ASIC);

[0017] Figure 2 is a schematic diagram of a structure of a capacitor charging module according to some embodiments of the present application;

[0018] Figure 3 is a schematic diagram of a capacitor charging module according to some embodiments of the present application;

[0019] Figure 4 is a schematic diagram of a charging performance of an application specific integrated circuit (ASIC), wherein the horizontal axis represents a voltage VBAT applied to a boost converter, and the vertical axis represents the charging performance of the ASIC. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings to make a clear and complete description of the embodiments of the present application. It should be noted that the described embodiments are only some of the embodiments of the technical solutions of the present application but not all. All other embodiments obtained by those of ordinary skill in the art based on the embodiments described in the present application file without creative labor are covered by the protection scope of the present application.

[0021] Generally, during the charging of a capacitor, the charging current first increases and then decreases until the charging current is zero, and correspondingly, the capacitor voltage increases from small to large until it is the same as the charging voltage.

[0022] Figure 2 is a schematic diagram of a structure of a capacitor charging module according to some embodiments of the present application. As an example, the charging module can be provided in an ASIC, such as an ASIC of a safety airbag control system, as a charging module for charging an energy storage capacitor.

[0023] As shown in Figure 2 The charging module includes a boost converter 30, a voltage dividing module 32, a current regulating module 34, and a power terminal comparing module 306. The voltage dividing module 32 is electrically connected to the output of the boost converter 30 to obtain a first feedback signal U1 and a second feedback signal U2 reflecting the output voltage Vout of the boost converter 30. The boost converter 30 is configured to receive an input voltage and convert the input voltage to an output voltage at the output. The current regulating module 34 compares the first feedback signal U1 with a first reference signal, and in the case that the first feedback signal U1 is greater than the first reference signal, the current regulating module 34 increases the charging current of the energy storage capacitor ERC in the charging mode, and in the case that the first feedback signal U1 is less than the first reference signal, the current regulating module 34 stops increasing the charging current of the energy storage capacitor in the charging mode. The power terminal comparing module 306 receives a second reference signal and outputs a control signal for controlling the output of the boost converter 30 based on the comparison result of the second reference signal and the second feedback signal U2.

[0024] The first feedback signal, the first reference signal, the second feedback signal, and the second reference signal can be a signal representing voltage (referred to as a voltage signal) or a signal representing current (referred to as a current signal). In the examples of the present application, the first feedback signal, the first reference signal, the second feedback signal, and the second reference signal are all voltage signals. In addition, the first reference signal and the second reference signal can be the same or different, and can be pre-set. In the examples of the present application, the first reference signal and the second reference signal are the same signal, and specifically represent a voltage Vref.

[0025] When the charging module of the examples of the present application charges the energy storage capacitor, the current regulating module 34 can adaptively regulate the charging current input to the energy storage capacitor ERC according to the comparison result of the first feedback signal U1 and the first reference signal. For example, the output voltage Vout of the boost converter 30 is 33 volts, and the voltage as the reference signal is 2.5 volts. According to the examples of the present application, as long as the voltage represented by the first feedback signal U1 collected by the voltage dividing module 32 is greater than the voltage of the first reference signal (also referred to herein as the reference voltage), i.e., greater than 2.5 volts, the current regulating module 34 can increase the charging current in the charging mode. During this period, even if the output voltage Vout of the boost converter 30 changes, as long as the first feedback signal U1 does not decrease below the reference voltage due to the change in the output voltage Vout, the charging current can be increased to charge the energy storage capacitor faster.

[0026] Figure 3 is a structural diagram of a capacitor charging module according to some specific embodiments of the present application. The charging module in this example can be applied to an ASIC in a vehicle airbag control system to charge an energy storage capacitor 500 of the airbag control system.

[0027] Referring to Figure 3 The charging module includes a boost converter 40 receiving input power 400, a voltage dividing module 42 and a current regulating module 44. The voltage dividing module 42 includes a first voltage dividing unit, a second voltage dividing unit and a third voltage dividing unit. The input of the first voltage dividing unit is connected to the output of the boost converter 40, and the output of the first voltage dividing unit is connected to the input of the second voltage dividing unit. The output of the second voltage dividing unit is connected to the input of the third voltage dividing unit. The first voltage dividing unit and the second voltage dividing unit cooperate with the third voltage dividing unit to divide the voltage Vout in a certain proportion to obtain the required voltage. According to the example of the present application, the first feedback signal U1 is collected between the first voltage dividing unit and the second voltage dividing unit, and the second feedback signal U2 is collected between the second voltage dividing unit and the third voltage dividing unit. The first voltage dividing unit, the second voltage dividing unit and the third voltage dividing unit are configured in such a way that the voltage represented by the first feedback signal U1' is greater than the voltage represented by the second feedback signal U2'.

[0028] By way of example but not limitation, the first voltage dividing unit employs a voltage dividing resistor R1, the second voltage dividing unit employs a voltage dividing resistor R2, and the third voltage dividing unit employs a voltage dividing resistor R3. In some examples, the resistance value of the voltage dividing resistor R1 is greater than the resistance value of the voltage dividing resistor R2, and the resistance value of the voltage dividing resistor R2 is greater than the resistance value of the voltage dividing resistor R3. Alternatively, the resistance sum of the voltage dividing resistor R2 and the voltage dividing resistor R3 is greater than the resistance value of the voltage dividing resistor R3. Through the above configuration, the voltage represented by the first feedback signal U1' is greater than the voltage represented by the second feedback signal U2'.

[0029] The current regulating module 44 includes a first comparator 440 and a driver 460. The first feedback signal U1' is transmitted to the comparator 440, and the second feedback signal U2' is transmitted to the power end comparison module 401. Specifically, the power end comparison module 401 is a comparator, hereinafter directly referred to as the power end comparator 401. In a specific example, the first feedback signal U1' is sent to the inverting terminal of the first comparator 440, and the reference signal V'ref is sent to the non-inverting terminal of the first comparator 440; the second feedback signal U2' is sent to the inverting terminal of the power end comparator 401, and the reference signal V'ref is sent to the non-inverting terminal of the power end comparator 401.

[0030] The power terminal comparator 401 is part of the pulse width modulation signal PWM generation module of the boost converter 40. The power terminal comparator 401 generates a control signal based on the comparison of the second feedback signal U2' and the reference signal V'ref, which after duty cycle control and other processing controls the output of the boost converter 40. The output voltage of the boost converter 40 decreases, and the voltage represented by the second feedback signal U2' decreases accordingly. If the output voltage decreases to the point that the second feedback signal U2' is less than the reference signal V'ref, the boost converter 40 enters the maximum power output mode. In the maximum power output mode, the output current Iout of the boost converter 40 increases as the output voltage V'out of the boost converter 40 decreases. In the present example, the comparison of the feedback signal and the reference signal is a comparison of the voltage represented by the feedback signal and the voltage represented by the reference signal. As mentioned above, the reference signal is also referred to as a reference voltage.

[0031] The first comparator 440 of the current regulation module 44 compares the first feedback signal U1' to the reference signal. When the first feedback signal U1' is greater than the reference voltage V'ref, the output signal of the first comparator 440 causes the driver 460 to increase the charging current during the charging current increase phase. For example, when the output voltage of the boost converter 40 is Vout1, and the corresponding output current is Iout1, the voltage represented by the first feedback signal U1' is greater than the reference voltage V'ref, and the current regulation module 44 increases the charging current to the energy storage capacitor 500 until the first feedback signal U1' is less than the reference voltage V'ref.

[0032] Figure 4 The charging performance of an application specific integrated circuit (ASIC) is illustrated, where the horizontal axis represents the voltage VBAT applied to the boost converter, and the vertical axis represents the charging performance of the ASIC, the maximum performance output current is represented by the line 200max, and the minimum performance output current is represented by the line 200min. In the case of a conventional charging module, to ensure that the output current of the charging power supply does not exceed the limit of the output current of the boost converter, the charging current of the energy storage capacitor is usually set to be substantially equal to the average of the maximum performance current and the minimum performance current of the ASIC, as illustrated by the line 200.

[0033] With the charging module according to the present example, the current regulation module can increase the charging current adaptively during the charging current increase phase of the charging process based on the comparison of the first reference signal and the first feedback signal, without considering the related output characteristics of the ASIC, such as the output voltage variation, so that the energy storage capacitor ERC can be charged faster. In this way, the charging current can be as close as possible to the maximum performance current of the ASIC without exceeding it.

[0034] Reference Figure 3When the input voltage to the boost converter 40 is 6V, the output voltage of the boost converter 40 is, for example, 33V, and the maximum performance current of the ASIC is Imax. During the charging of the energy storage capacitor 500, the first feedback signal U1'is greater than the reference voltage of 2.5V, and the current regulation module 44 will increase the charging current of the energy storage capacitor 500, for example, to 90% of Imax. During the charging, if the ASIC including the boost converter 40 for some reason decreases the output voltage, for example, to 30V, at this time, the first feedback signal U1'and the second feedback signal U2'both decrease, and if the first feedback signal U1'decreases to less than the reference signal, the output of the first comparator 440 will cause the current regulation module 44 to stop increasing the charging current. When the output voltage decreases further so that the second feedback signal U2'is also less than the reference signal representing the voltage (i.e., the reference voltage), the output of the power supply end comparator 401 will cause the boost conversion module 40 to operate in the maximum power mode, at this time, the output current increases due to the decrease of the output voltage and can increase to Imax, but because the first feedback signal U1'is less than the reference signal V'ref before the second feedback signal U2 ', and the current regulation module has stopped increasing the current for charging the energy storage capacitor 500 accordingly, therefore, although the output current of the boost converter increases and can increase to the maximum performance current Imax, the charging current has stopped increasing under the control of the current regulation module. Accordingly, both the current for charging the energy storage capacitor 500 is relatively large to improve the charging speed, and it is ensured that the charging current does not reach the maximum performance current.

[0035] Further, if the ASIC module changes, for example, its maximum performance current increases, for example, greater than Imax6 in the foregoing example, when the charging module according to the examples of the present application is used, it is also not necessary to adjust the charging current for charging the energy storage capacitor. The first comparator 440 can increase the charging current and stop increasing the charging current according to the comparison result of the first feedback signal and the reference signal.

[0036] According to the examples of the present application, a safety airbag controller is also provided. The safety airbag controller includes any one of the charging modules described above. According to the examples of the present application, a safety airbag system is also provided, which includes the safety airbag controller, or includes any one of the charging modules described above.

[0037] In addition, in the above examples of the present application, the voltage converter is a boost converter. However, in other application scenarios, the voltage converter can be a step-down converter, for example, the input voltage is high, and the voltage converter converts it to a lower voltage.

[0038] The technical features in the various embodiments of the present application can be combined with each other without departing from the spirit of the present application and without conflicting with each other, to form new embodiments. Although specific embodiments of the present application have been shown and described in detail to explain the principles of the present application, it should be understood that the present application can be implemented in other ways without departing from such principles.

Claims

1. A capacitive charging module, characterized by, The charging module comprises: a voltage converter for converting an input voltage into an output voltage; a voltage dividing module electrically connected to an output of the voltage converter to obtain a first feedback signal and a second feedback signal for reflecting the output voltage of the voltage converter; a current regulating module for comparing the first feedback signal with a first reference signal and increasing a charging current of an energy storage capacitor in a charging mode if the first feedback signal is greater than the first reference signal and not increasing the charging current of the energy storage capacitor in the charging mode if the first feedback signal is less than the first reference signal; a power terminal comparing module receiving a second reference signal and outputting a control signal for controlling an output of the charging power supply based on a comparison between the second reference signal and the second feedback signal.

2. The charging module of claim 1, wherein, The voltage dividing module comprises: a first voltage dividing unit, an input of the first voltage dividing unit being connected to an output of the charging power supply; a second voltage dividing unit, an input of the second voltage dividing unit being connected to an output of the first voltage dividing unit; a third voltage dividing unit, an input of the third voltage dividing unit being connected to an output of the second voltage dividing unit; and wherein the first feedback signal is collected from a connection between the first voltage dividing unit and the second voltage dividing unit; wherein the second feedback signal is collected from a connection between the first voltage dividing unit and the second voltage dividing unit; wherein the first voltage dividing unit, the second voltage dividing unit and the third voltage dividing unit are configured such that a voltage represented by the first feedback signal is greater than a voltage represented by the second feedback signal.

3. The charging module of claim 2, wherein, The first voltage dividing unit, the second voltage dividing unit and the third voltage dividing unit are resistors.

4. The charging module of claim 1, wherein, The current regulating module comprises: a first comparator, inputs of the first comparator receiving the first feedback signal and the first reference signal; a driver, an input of the driver being connected to an output of the first comparator to adjust the charging current according to the output signal.

5. The charging module of claim 4, wherein, The first feedback signal is input into an inverting input of the first comparator and the first reference signal is input into a non-inverting input of the first comparator.

6. The charging module of claim 1, wherein, The first feedback signal and the first reference signal are voltage signals or current signals; and the second feedback signal and the first reference signal are voltage signals or current signals.

7. The charging module of claim 1, wherein, The voltage converter is a boost converter.

8. The charging module according to any one of claims 1 to 7, characterized in that, The first reference signal and the second reference signal are the same.

9. An airbag controller configured with an energy storage capacitor, characterized by, The airbag controller comprises the charging module according to any one of claims 1 to 8.

10. An airbag system characterized by comprising: The airbag controller comprises the charging module according to any one of claims 1 to 8.

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