Smart fuse control circuit and control method thereof

Abstract

A smart fuse control circuit and control method thereof, the smart fuse control circuit comprising a high-side switch, a power supply circuit, a drive and protection circuit, a continuous current detection circuit, a periodic circulating current monitoring circuit, a controller, and an SBC. The first and second input terminals of the drive and protection circuit are respectively connected to the first output terminal of the controller and the output terminal of the continuous current detection circuit, and the first and second output terminals of the drive and protection circuit are respectively connected to the control terminal of the high-side switch and the second input terminal of the SBC. The enable input terminal of the periodic circulating current monitoring circuit is connected to the second output terminal of the controller, and the first and second output terminals of the periodic circulating current monitoring circuit are respectively connected to the first input terminal of the SBC and the signal input terminal of the controller. The SBC is connected to the controller. The present invention has low quiescent current consumption and can provide more comprehensive diagnostic and protection functions.

Description

Technical Field

[0001] The present invention relates to power supply control technology, and in particular to smart fuse technology. Background Art

[0002] Figure 1 A known automotive smart fuse control circuit for achieving a normally-open output is shown. The circuit includes a high-side switch 91, a smart fuse integrated control chip 92, an MCU 93, and a system basis chip (SBC) 94. The smart fuse integrated control chip 92 integrates a power supply circuit 921, a drive and protection circuit 922, and a current detection circuit 923. It lacks a sleep function and consumes a relatively high quiescent current. Simultaneously, the MCU 93 and the system basis chip (SBC) also consume significant quiescent current, resulting in a significant total quiescent current consumption. This leads to continuous power consumption while the vehicle is parked, potentially causing battery depletion if the vehicle is parked for extended periods. However, putting the smart fuse integrated control chip into a fully sleep state would not meet the normally-open output requirement.

[0003] In actual working conditions, the ignition key is in the OFF position, which corresponds to the sleep state. In the sleep state, the system basic chip SBC and MCU are both in sleep state. The ignition key is in the ON position / ST position, which corresponds to the continuous activation state. Generally, after the ignition key is turned to the ON position, the vehicle body control module BCM or the upper-level controller completes initialization and wakes up the system basic chip SBC through the CAN bus. The system basic chip SBC powers the MCU, and the MCU is then woken up.

[0004] Existing smart fuse integrated control chips 92 provide both overcurrent protection and short-circuit protection. For example, if the current detected by the current detection circuit 923 exceeds 20A, the driver and protection circuit 922 activates overcurrent protection and shuts off the high-side switch 91. If the current detected by the current detection circuit 923 exceeds 100A, short-circuit protection is activated and shuts off the high-side switch 91. Short-circuit protection also responds more quickly. Both 20A and 100A are considered overcurrent thresholds. However, the current monitoring capabilities of existing smart fuse control circuits are not comprehensive. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an intelligent fuse control circuit with low quiescent current consumption and capable of providing more comprehensive diagnosis and protection functions.

[0006] Another technical problem to be solved by the present invention is to provide a control method for an intelligent fuse control circuit.

[0007] An intelligent fuse control circuit according to an embodiment of the present invention includes a high-side switch, a drive and protection circuit, a system basis chip (SBC), and a controller, wherein a first input terminal of the drive and protection circuit is connected to a first output terminal of the controller, and a first output terminal of the drive and protection circuit is connected to a control terminal of the high-side switch; the system basis chip (SBC) is connected to the controller; the intelligent fuse control circuit includes a continuous current detection circuit and a periodic circulation current monitoring circuit, wherein the current detection accuracy and nominal quiescent current of the continuous current detection circuit are lower than those of the periodic circulation current monitoring circuit; the continuous current detection circuit is used to continuously detect the current flowing through the high-side switch, and the output terminal of the continuous current detection circuit is connected to a second input terminal of the drive and protection circuit; the enable input terminal of the periodic circulation current monitoring circuit is connected to the second output terminal of the controller, the first output terminal of the periodic circulation current monitoring circuit is connected to the first input terminal of the system basis chip (SBC), and the second output terminal of the periodic circulation current monitoring circuit is connected to a signal input terminal of the controller; the periodic circulation current monitoring circuit is used to continuously detect the current flowing through the high-side switch after being enabled by the controller and send the detection result to the controller, When not enabled by the controller, the system switches between a sleep state and an awake state. After entering the sleep state, if the sleep time reaches a preset sleep time threshold, the system switches from the sleep state to the awake state. After entering the awake state, the system detects the current flowing through the high-side switch. If the current flowing through the high-side switch is detected to be greater than or equal to a preset awakening current threshold, the system base chip SBC is awakened. If the current flowing through the high-side switch is detected to be less than the preset awakening current threshold, the system switches to the sleep state when the awakening time reaches the preset awakening time threshold. The second output terminal of the driving and protection circuit is connected to the second input terminal of the system base chip SBC. The driving and protection circuit is used to compare the current value detected by the continuous current detection circuit with a preset overcurrent threshold. When the current value detected by the continuous current detection circuit is greater than or equal to the preset overcurrent threshold, the high-side switch is controlled to be turned off and the system base chip SBC is awakened. The system base chip SBC and the controller are respectively used to remain in sleep when not awakened. The system base chip SBC is used to supply power to the controller after being awakened and control the awakening and sleep of the controller. The controller is used to enable the periodic cycle current monitoring circuit after being awakened.

[0008] A control method for a smart fuse control circuit according to an embodiment of the present invention includes the following steps:

[0009] After the system basis chip SBC goes into sleep mode, the continuous current detection circuit continuously detects the current flowing through the high-side switch and sends the detection result to the driving and protection circuit. The periodic cycle current monitoring circuit switches between a sleep state and a wake-up state. After entering the sleep state, if the sleep time reaches a preset sleep time threshold, the circuit switches from the sleep state to the wake-up state. After entering the wake-up state, the circuit detects the current flowing through the high-side switch. If the current flowing through the high-side switch is detected to be greater than or equal to the preset wake-up current threshold, the system basis chip SBC wakes up. If the current flowing through the high-side switch is detected to be less than the preset wake-up current threshold, the circuit switches to the sleep state when the wake-up time reaches the preset wake-up time threshold. The current detection accuracy and nominal quiescent current of the continuous current detection circuit are lower than those of the periodic cycle current monitoring circuit.

[0010] The driving and protection circuit compares the current value detected by the continuous current detection circuit with a preset overcurrent threshold, and controls the high-side switch to turn off when the current value detected by the continuous current detection circuit is greater than or equal to the preset overcurrent threshold, and wakes up the system basis chip SBC;

[0011] The system basis chip SBC wakes up the controller after being woken up. The controller enables the periodic cycle current monitoring circuit after being woken up by the system basis chip SBC. After being enabled, the periodic cycle current monitoring circuit continuously detects the current flowing through the high-side switch and sends the detection result to the controller.

[0012] The present invention has at least the following advantages and features:

[0013] 1. This embodiment of the present invention uses a low-precision, low-nominal quiescent current continuous current detection circuit to continuously provide current detection signals to the drive and protection circuits. This ensures low quiescent current consumption without affecting overcurrent protection. Furthermore, this embodiment uses a high-precision, but relatively high-nominal quiescent current, periodic circulating current monitoring circuit to provide a more accurate current detection signal to the controller. After the entire circuit goes into hibernation, the periodic circulating current monitoring circuit remains in a periodic wake-up state when the current is less than a preset wake-up circuit threshold. Therefore, the entire operating time of the periodic circulating current monitoring circuit is very short, thereby ensuring low quiescent current consumption for the entire circuit without affecting the protection function.

[0014] 2. In the embodiment of the present invention, after hibernation, if the periodic circulating current monitoring circuit detects that the current is greater than or equal to the preset wake-up current threshold after waking up, the periodic circulating current monitoring circuit will wake up the system basic chip SBC and the controller. The controller enables the periodic circulating current monitoring circuit to switch it from the periodic current monitoring mode to the continuous current monitoring mode. The controller can provide more comprehensive diagnostic and protection functions based on the high-precision current detection results continuously provided by the periodic circulating current monitoring circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the circuit principle of an existing intelligent fuse control circuit is shown.

[0016] Figure 2 FIG. 4 is a schematic diagram of a smart fuse control circuit according to an embodiment of the present invention.

[0017] Figure 3 A principle block diagram of a periodic circulating current monitoring circuit according to an embodiment of the present invention is shown.

[0018] Figure 4 A flow chart of a control method of a smart fuse control circuit according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 2 FIG1 shows a schematic diagram of the circuit principle of the intelligent fuse control circuit according to an embodiment of the present invention. Figure 2 The smart fuse control circuit according to an embodiment of the present invention includes a voltage input terminal In, a voltage output terminal Out, a high-side switch 1, a power supply circuit 2, a drive and protection circuit 3, a continuous current detection circuit 41, a periodic cycle current monitoring circuit 42, a controller 5 and a system basis chip SBC6.

[0021] The voltage input terminal In is used to connect to an external power source. In this embodiment, the smart fuse control circuit is a vehicle-mounted smart fuse control circuit, and the external power source is a vehicle battery. Figure 2 KL30 in the figure represents the output voltage of the positive terminal of the car battery.

[0022] The first end of the high-side switch 1 is connected to the voltage input terminal In, and the second end of the high-side switch 1 is connected to the voltage output terminal Out. The high-side switch 11 provides a power path from input to output. In this embodiment, the high-side switch 1 is composed of two MOS transistors connected back-to-back. Preferably, the two MOS transistors are NMOS transistors, and the drains of the two NMOS transistors are connected together.

[0023] The input terminal of the power supply circuit 2 is connected to the voltage input terminal In, and the output terminal of the power supply circuit 2 is connected to the power input terminal of the driving and protection circuit 3. The power supply circuit 2 converts the output voltage of the external power supply into the operating voltage of the driving and protection circuit 3. In this embodiment, the power supply circuit 2 is composed of a boost circuit, which can be a pump-boost circuit or other types of boost circuits.

[0024] The continuous current detection circuit 41 is used to continuously detect the current flowing through the high-side switch 1 and send the current detection result to the driving and protection circuit 3 .

[0025] A first input terminal of the driving and protection circuit 3 is connected to a first output terminal of the controller 5, and a second input terminal of the driving and protection circuit 3 is connected to an output terminal of the continuous current detection circuit 41. The first output terminal of the driving and protection circuit 3 is connected to a control terminal of the high-side switch 1 to drive the high-side switch 1 and provide protection by shutting off the high-side switch 1. A second output terminal of the driving and protection circuit 3 is connected to a second input terminal of the system basis chip SBC6. The driving and protection circuit 3 is configured to compare the current value detected by the continuous current detection circuit 41 with a preset overcurrent threshold. When the current value detected by the continuous current detection circuit 41 is greater than or equal to the preset overcurrent threshold, the driving and protection circuit 3 controls the high-side switch 1 to shut off and outputs a second wake-up signal to the system basis chip SBC6 to wake up the system basis chip SBC6.

[0026] The current detection accuracy and nominal quiescent current consumption of the continuous current detection circuit 41 are lower than those of the periodic cycle current monitoring circuit 42. The power input terminal of the periodic cycle current monitoring circuit 42 is connected to the voltage input terminal In. The enable input terminal of the periodic circulating current monitoring circuit 42 is connected to the second output terminal of the controller 5, the first output terminal of the periodic circulating current monitoring circuit 42 is connected to the first input terminal of the system basis chip SBC6, and the second output terminal of the periodic circulating current monitoring circuit 42 is connected to the signal input terminal of the controller 5. The periodic current monitoring circuit 42 is used to continuously detect the current flowing through the high-side switch 1 after being enabled by the controller 5 and send the detection result to the controller 5. When not enabled by the controller 5, the periodic current monitoring circuit 42 switches between a sleep state and a wake-up state. After entering the sleep state, if the sleep time reaches a preset sleep time threshold, the periodic current monitoring circuit 42 switches from the sleep state to the wake-up state. After entering the wake-up state, the periodic current monitoring circuit 42 detects the current flowing through the high-side switch 1. If it is detected that the current flowing through the high-side switch is greater than or equal to the preset wake-up current threshold, the periodic current monitoring circuit 42 outputs a first wake-up signal to the system basis chip SBC6 to wake up the system basis chip SBC6. If it is detected that the current flowing through the high-side switch is less than the preset wake-up current threshold, the periodic current monitoring circuit 42 switches to the sleep state when the wake-up time reaches the preset wake-up time threshold.

[0027] The controller 5 can implement It protection, I 2 t protection, over temperature protection and other protection functions. If the It protection, I 2t protection, over-temperature protection, etc., the controller 5 will turn off the enable of the driving and protection circuit 3, so that the high-side switch 1 corresponding to the driving and protection circuit 3 is turned off. It protection is when the current increases over time and exceeds a preset threshold (which can be a step threshold) and lasts for more than a specified time, the protection is activated. 2 T protection is used for wiring harness protection. The square of the current corresponds to the effective value of the current, which corresponds to the heating of the wiring harness. The integral of the square of the current over time is calculated. When the integral value exceeds the set threshold, the protection is activated.

[0028] In this embodiment, the preset wake-up time threshold is less than the preset sleep time threshold. The periodic cycle current monitoring circuit 42 includes a periodic wake-up circuit 421 and a current monitoring circuit 422. Figure 3 As shown. The output of the periodic wake-up circuit 421 is connected to the wake-up input of the current monitoring circuit 422. The periodic wake-up circuit 421 is configured to wake up the current monitoring circuit 422 according to a preset wake-up period, where the wake-up period is greater than a preset sleep time threshold. The enable input of the current monitoring circuit 422 is connected to the second output of the controller 5, the first output of the current monitoring circuit 422 is connected to the first input of the system basis chip SBC6, and the second output of the current monitoring circuit 422 is connected to the signal input of the controller 5. After being enabled by the controller 5, the current monitoring circuit 422 is configured to continuously detect the current flowing through the high-side switch 1 and send the detection result to the controller 5. When not enabled by the controller 5, the current monitoring circuit 422 switches between a sleep state and a wake-up state. After being awakened by the periodic wake-up circuit 421, the current flowing through the high-side switch 1 is detected. If the current flowing through the high-side switch is detected to be greater than or equal to a preset wake-up current threshold, the system basis chip SBC6 is awakened. If the current flowing through the high-side switch is detected to be less than the preset wake-up current threshold, the system is switched to a sleep state when the wake-up time reaches the preset wake-up time threshold. Optionally, the periodic wake-up circuit 421 is a timer circuit, which may adopt a timer chip with low quiescent current, or be composed of discrete electronic components.

[0029] The periodic wake-up circuit 421 periodically wakes up the current monitoring circuit 422. In one specific embodiment, the wake-up period of the periodic wake-up circuit 421 is 1 second. Every 1 second, the periodic wake-up circuit 421 wakes up the current monitoring circuit 422. The current monitoring circuit 422 completes the current monitoring function within 1 millisecond (i.e., the wake-up time threshold is 1 millisecond) and then enters the sleep state again.

[0030] Therefore, for 999ms (i.e., the sleep time threshold is 999ms), current monitoring circuit 422 remains in a sleep state, and the average quiescent current consumed by the entire system is very low. During the 1ms period of activation, current monitoring circuit 422 completes current monitoring. If the current reaches a preset wake-up current threshold (e.g., 5A), system base chip SBC6 and controller 5 are awakened, causing current monitoring circuit 422 to switch from periodic monitoring to continuous monitoring mode (described in detail below). If the current does not reach the preset wake-up current threshold, the system remains in a periodic current monitoring state, consuming a higher quiescent current for 0.1% of the time and operating in a low quiescent current state for the remaining 99.9% of the time. Consequently, the average quiescent current consumed by the entire system is very low.

[0031] In this embodiment, the continuous current detection circuit 41 is composed of a first current detection chip with a low nominal quiescent current but relatively low accuracy, which is used for overcurrent protection and short-circuit protection (since the overcurrent threshold is generally large, the current detection chip used for overcurrent protection and short-circuit protection does not need to be very accurate). A current detection chip with a lower nominal quiescent current and current detection accuracy than the current detection circuit in the prior art can be selected; the current monitoring circuit 422 is composed of a second current detection chip with high accuracy but a relatively high nominal quiescent current, which is used to provide accurate current monitoring for the controller 5.

[0032] Currently, there are no chips on the market that have both high current detection accuracy and low nominal quiescent current. The continuous current detection circuit 41 uses a low-precision current detection chip with a low nominal quiescent current. This chip consumes a small amount of quiescent current, but has low accuracy, especially when detecting small currents. However, when detecting large currents (overcurrents), it has relatively high accuracy and a fast response speed. Due to its low accuracy, it cannot monitor small currents and cannot provide accurate IT protection and I 2 t protection. The current detection chip used by the current monitoring circuit 422 has high accuracy, even when detecting small currents, and can provide accurate It protection and I 2 t protection, but its disadvantage is that the nominal quiescent current is high. Under the same working time, the actual quiescent current consumption is greater than that of the low-precision current detection chip, and the response speed is also not as fast as the low-precision current detection chip. The periodic wake-up circuit 421 consumes a certain amount of quiescent current, but it is very small. Especially when multiple smart fuses are used, the periodic wake-up circuit 421 can also be shared. In the embodiment of the present invention, although the nominal quiescent current of the high-precision current detection chip is high, since the wake-up time is very short, the total quiescent current actually consumed by the continuous current detection circuit 41, the periodic wake-up circuit 421 and the current monitoring circuit 422 will be lower than the quiescent current consumed by the current detection circuit in the prior art.

[0033] In a specific embodiment, if a 0.5 milliohm sampling resistor is used, the maximum absolute accuracy of the first current detection chip is 6A, and the nominal quiescent current value is 5uA; the maximum absolute accuracy of the second current detection chip is 0.1A, and the nominal quiescent current value is 60uA.

[0034] Absolute detection accuracy depends on the current sensing chip's input offset voltage and the selected sampling resistor value. Assuming the maximum input offset voltage over the full temperature range is 3mV and the selected sampling resistor is 0.5 milliohm, the maximum absolute accuracy over the full temperature range is 3mV / 0.5 milliohm = 6A. For low-current detection, assuming a current of 1A, the relative error is 6A / 1A = 600%. For 100A, the error is 6A / 100A = 6%. Chips with poor accuracy cannot meet current monitoring requirements and can only be used for overcurrent protection and short-circuit protection. High-accuracy chips meet current monitoring requirements, but their quiescent current is too high to be used directly in systems that keep the output permanently on during sleep mode.

[0035] If the current detection chip used in current monitoring circuit 422 has a nominal maximum quiescent current of 60uA, it operates for only 1ms of a 1s cycle, remaining dormant for the remaining 999ms. Therefore, its average maximum quiescent current consumption is a negligible 0.06uA. The maximum quiescent current consumption of periodic wake-up circuit 421 is 0.4uA, resulting in a total maximum quiescent current consumption of only 0.46uA for the periodic current monitoring circuit 42. Adding the 5uA consumption of continuous current detection circuit 41, the total maximum quiescent current consumption is only 5.46uA. In contrast, existing smart fuse integrated control chip solutions often consume tens of microamperes of quiescent current per chip.

[0036] In this embodiment, the input end of the continuous current detection circuit 41 and the input end of the periodic cycle current monitoring circuit 42 are respectively connected to the output end of the high-side switch 1. In other embodiments, the input end of the continuous current detection circuit 41 and the input end of the periodic cycle current monitoring circuit 42 are respectively connected to the input end of the high-side switch 1.

[0037] A power input terminal of the system basis chip SBC6 is connected to the voltage input terminal In, and the system basis chip SBC6 is connected to the controller 5. The system basis chip SBC6 and the controller 5 remain dormant when not awakened. After being awakened, the system basis chip SBC6 is configured to supply power to the controller 5 and control the awakening and dormancy of the controller 5. After being awakened, the controller 5 is configured to enable the periodic circulating current monitoring circuit.

[0038] In this embodiment, the controller 5 is an MCU. The MCU controls the enabling of the drive and protection circuit 3 (by sending a drive enable signal to enable the drive and protection circuit 3) and the enabling of the periodic current monitoring circuit 42 (by sending a current monitoring enable signal to the periodic current monitoring circuit 42 to switch it from periodic current monitoring mode to continuous current monitoring mode). The system basis chip (SBC6) integrates a CAN transceiver, an SPI communication module, a watchdog timer, an LDO circuit, and other components. The power input of the system basis chip (SBC6) is used to connect to an external power supply. The power output of the system basis chip (SBC6) is connected to the power input of the MCU5. The LDO circuit in the system basis chip (SBC6) provides power VDD to the MCU5, and the system basis chip (SBC6) is in communication with the MCU5. The MCU5 utilizes the bus communication interface of the system basis chip (in this embodiment, a CAN transceiver) to perform CAN communication functions. The MCU5 also has an SBC watchdog timer function.

[0039] In actual working conditions, the ignition key is in the OFF position, which corresponds to the dormant state. In the dormant state, the system basic chip SBC and the controller are both in dormant state. The ignition key is in the ON position / ST position, which corresponds to the continuously activated state. Generally, after the ignition key is turned to the ON position, the vehicle body control module BCM or the upper-level controller completes initialization and wakes up the system basic chip SBC through the CAN bus. The system basic chip SBC supplies power to the controller, and the controller is then woken up.

[0040] Please combine Figure 4 The control method of the smart fuse control circuit according to an embodiment of the present invention can monitor the current flowing through the high-side switch in a low quiescent current consumption manner when the circuit is in a dormant state, and the method includes the following steps:

[0041] After the system basis chip SBC6 goes into sleep mode, the continuous current detection circuit 41 continuously detects the current flowing through the high-side switch 1 and sends the detection result to the driving and protection circuit 3. The periodic cycle current monitoring circuit 42 switches between a sleep state and a wake-up state. After entering the sleep state, if the sleep time reaches a preset sleep time threshold, the system basis chip SBC6 switches from the sleep state to the wake-up state. After entering the wake-up state, the system basis chip SBC6 detects the current flowing through the high-side switch 1. If it is detected that the current flowing through the high-side switch is greater than or equal to the preset wake-up current threshold, the system basis chip SBC6 wakes up. If it is detected that the current flowing through the high-side switch 1 is less than the preset wake-up current threshold, the system basis chip SBC6 switches to the sleep state when the wake-up time reaches the preset wake-up time threshold.

[0042] The driving and protection circuit 3 compares the current value detected by the continuous current detection circuit 41 with a preset overcurrent threshold value. When the current value detected by the continuous current detection circuit 41 is greater than or equal to the preset overcurrent threshold value, the high-side switch 1 is turned off and the system basis chip SBC6 is awakened.

[0043] The system basis chip SBC6 wakes up the controller 5 after being awakened. The controller 5 enables the periodic cycle current monitoring circuit 42 after being awakened by the system basis chip SBC6. After being enabled, the periodic cycle current monitoring circuit 42 continuously detects the current flowing through the high-side switch 1 and sends the detection result to the controller 5.

[0044] Furthermore, when the current detection value sent by the periodic circulating current monitoring circuit 42 is continuously less than the wake-up current threshold for a preset period of time, the controller 5 controls the system basic chip SBC6 to enter a sleep state and stops enabling the periodic circulating current monitoring circuit 42.

[0045] The control method of the smart fuse control circuit according to the embodiment of the present invention implements the following three working conditions:

[0046] Working condition 1 (complete dormancy):

[0047] The current monitoring circuit 422 within the periodic current monitoring circuit 42 is in an unaware state and does not monitor the current flowing through the high-side switch 1. At this point, only the power supply circuit 2, the drive and protection circuit 3, and the continuous current detection circuit 41 consume quiescent current. In addition, the periodic wake-up circuit 421 within the periodic current monitoring circuit 42 also consumes a small amount of quiescent current. The entire system maintains very low quiescent current consumption.

[0048] Working condition 2 (intermittent activation state):

[0049] The periodic wake-up circuit 421 inside the periodic circulating current monitoring circuit 42 wakes up the current monitoring circuit 422 inside it, and the current monitoring circuit 422 is in a periodic current monitoring working state, monitoring the current flowing through the high-side switch 1; at this time, only the power supply circuit 2, the drive and protection circuit 3, the continuous current detection circuit 41 and the periodic circulating current monitoring circuit 42 consume static current.

[0050] Operating condition 2 has an additional quiescent current consumption of the current monitoring circuit 422, and the quiescent current consumed will be larger than that of operating condition 1, but the duration of operating condition 2 is much shorter than that of operating condition 1, and the proportion of the time of the entire parking state (complete sleep state and intermittent activation state) is very small.

[0051] If the current flowing through the high-side switch is detected to be relatively small and does not reach the wake-up current threshold required to wake up the system basis chip SBC6, the current monitoring circuit 422 will enter the full sleep state again after a short operation, returning to operating condition 1. If the current flowing through the high-side switch is detected to be greater than or equal to the wake-up current threshold required to wake up the system basis chip SBC6, the system basis chip SBC6 will be woken up and the system basis chip SBC6 will enter operating condition 3.

[0052] Condition 3 (continuous activation):

[0053] When current monitoring circuit 422 within the periodic current monitoring circuit wakes up and detects that the current flowing through the high-side switch is greater than or equal to the set wake-up current threshold, system basis chip SBC6 wakes up, and controller 5 begins operating, controlling periodic current monitoring circuit 42 to switch from periodic current monitoring mode to continuous current monitoring mode, continuously monitoring current. At this point, power supply circuit 2, drive and protection circuit 3, continuous current monitoring circuit 41, periodic current monitoring circuit 42, system basis chip SBC6, and controller 5 are all in continuous operation.

[0054] When the controller 5 is awakened and the continuous current monitoring mode is activated, the controller 5 will provide diagnostic functions and more comprehensive protection, such as over-temperature protection, IT protection, wiring harness protection (I 2 t protection), fault storage, etc.

[0055] In summary, according to the control method for a smart fuse control circuit according to an embodiment of the present invention, when the key is in the OFF position (i.e., the system is in sleep mode), if an abnormality is detected, the system will enter a continuously active state. Once the abnormality is resolved, the system will return to sleep mode. During sleep mode, the periodic circulating current monitoring circuit will be intermittently activated (intermittent activation will continue during sleep mode).

[0056] When the current flowing through high-side switch 1 is detected to be large, greater than or equal to the overcurrent threshold, the driver and protection circuit 3 promptly triggers overcurrent protection or short-circuit protection, waking up the system base chip SBC6 and MCU5, eliminating any system risks. When the current flowing through high-side switch 1 is greater than or equal to the preset wake-up current threshold (e.g., due to MOSFET overheating), the system will wake up the system base chip SBC6 and MCU5 within a single wake-up cycle at most. Because the time required for a current equivalent to the wake-up current threshold to reach a current equivalent to the overcurrent threshold generally takes a long time, far longer than a single wake-up cycle, eliminating any system risks. When MCU5 detects that the current flowing through high-side switch 1 is very low (less than the wake-up current threshold) and remains below the wake-up current threshold for a specified period of time, MCU5 stops feeding the dog, returning the system base chip SBC6 to sleep, deactivates the current monitoring enable signal, and controls the periodic current monitoring circuit 42 to switch from continuous current monitoring mode to periodic current monitoring mode, returning it to periodic monitoring mode to conserve static current.

[0057] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A smart fuse control circuit, comprising a high-side switch, a drive and protection circuit, a system basis chip (SBC), and a controller, wherein a first input terminal of the drive and protection circuit is connected to a first output terminal of the controller, and a first output terminal of the drive and protection circuit is connected to a control terminal of the high-side switch; the system basis chip (SBC) is connected to the controller; characterized in that: The intelligent fuse control circuit includes a continuous current detection circuit and a periodic cycle current monitoring circuit. The current detection accuracy and nominal quiescent current of the continuous current detection circuit are lower than those of the periodic cycle current monitoring circuit. The continuous current detection circuit is used to continuously detect the current flowing through the high-side switch, and the output end of the continuous current detection circuit is connected to the second input end of the driving and protection circuit; The enable input terminal of the periodic circulating current monitoring circuit is connected to the second output terminal of the controller, the first output terminal of the periodic circulating current monitoring circuit is connected to the first input terminal of the system basis chip (SBC), and the second output terminal of the periodic circulating current monitoring circuit is connected to the signal input terminal of the controller. The periodic circulating current monitoring circuit is used to continuously detect the current flowing through the high-side switch after being enabled by the controller and send the detection result to the controller. When not enabled by the controller, the periodic circulating current monitoring circuit switches between a sleep state and a wake-up state. After entering the sleep state, if the sleep time reaches a preset sleep time threshold, the periodic circulating current monitoring circuit switches from the sleep state to the wake-up state. After entering the wake-up state, the current flowing through the high-side switch is detected. If it is detected that the current flowing through the high-side switch is greater than or equal to the preset wake-up current threshold, the system basis chip (SBC) is woken up. If it is detected that the current flowing through the high-side switch is less than the preset wake-up current threshold, the periodic circulating current monitoring circuit switches to the sleep state when the wake-up time reaches the preset wake-up time threshold. The second output terminal of the driving and protection circuit is connected to the second input terminal of the system basis chip SBC. The driving and protection circuit is used to compare the current value detected by the continuous current detection circuit with a preset overcurrent threshold, and control the high-side switch to turn off when the current value detected by the continuous current detection circuit is greater than or equal to the preset overcurrent threshold, and wake up the system basis chip SBC; The system basis chip SBC and the controller remain dormant when not awakened. The system basis chip SBC is used to power the controller after being awakened and control the awakening and dormancy of the controller. The controller is used to enable the periodic cycle current monitoring circuit after being awakened.

2. The smart fuse control circuit according to claim 1, wherein: The preset wake-up time threshold is smaller than the preset sleep time threshold.

3. The smart fuse control circuit according to claim 1, wherein: The periodic cyclic current monitoring circuit includes a periodic wake-up circuit and a current monitoring circuit; the output end of the periodic wake-up circuit is connected to the wake-up input end of the current monitoring circuit, the enable input end of the current monitoring circuit is connected to the second output end of the controller, the first output end of the current monitoring circuit is connected to the first input end of the system basis chip SBC, and the second output end of the current monitoring circuit is connected to the signal input end of the controller; The periodic wake-up circuit is used to wake up the current monitoring circuit according to a preset wake-up period, and the wake-up period is greater than the preset sleep time threshold; The current monitoring circuit is used to continuously detect the current flowing through the high-side switch after being enabled by the controller and send the detection result to the controller, and switch between a sleep state and a wake-up state when not enabled by the controller. Specifically, after being awakened by the periodic wake-up circuit, the current flowing through the high-side switch is detected. If it is detected that the current flowing through the high-side switch is greater than or equal to a preset wake-up current threshold, the system basis chip SBC is awakened. If it is detected that the current flowing through the high-side switch is less than the preset wake-up current threshold, the system switches to the sleep state when the wake-up time reaches the preset wake-up time threshold.

4. The smart fuse control circuit according to claim 3, wherein: The continuous current detection circuit and the current monitoring circuit are respectively composed of a first current detection chip and a second current detection chip. The current detection accuracy of the first current detection chip is lower than that of the second current detection chip, and the nominal static current of the first current detection chip is lower than that of the second current detection chip.

5. The smart fuse control circuit according to claim 1, wherein: The controller is used to control the system basis chip SBC to enter a sleep state and stop enabling the periodic cycle current monitoring circuit when the current detection value sent by the periodic cycle current monitoring circuit is continuously less than the wake-up current threshold for a preset time period.

6. The smart fuse control circuit according to claim 1, wherein: An input end of the continuous current detection circuit and an input end of the periodic cycle current monitoring circuit are respectively connected to an output end of the high-side switch.

7. The smart fuse control circuit according to claim 1, wherein: The controller is an MCU.

8. The smart fuse control circuit according to claim 1, wherein: The smart fuse control circuit is a vehicle-mounted smart fuse control circuit.

9. A control method for a smart fuse control circuit, characterized in that: After the system basis chip SBC goes into sleep mode, the continuous current detection circuit continuously detects the current flowing through the high-side switch and sends the detection result to the driving and protection circuit. The periodic cycle current monitoring circuit switches between a sleep state and a wake-up state. After entering the sleep state, if the sleep time reaches a preset sleep time threshold, the circuit switches from the sleep state to the wake-up state. After entering the wake-up state, the circuit detects the current flowing through the high-side switch. If the current flowing through the high-side switch is detected to be greater than or equal to the preset wake-up current threshold, the system basis chip SBC wakes up. If the current flowing through the high-side switch is detected to be less than the preset wake-up current threshold, the circuit switches to the sleep state when the wake-up time reaches the preset wake-up time threshold. The current detection accuracy and nominal quiescent current of the continuous current detection circuit are lower than those of the periodic cycle current monitoring circuit. The driving and protection circuit compares the current value detected by the continuous current detection circuit with a preset overcurrent threshold, and controls the high-side switch to turn off when the current value detected by the continuous current detection circuit is greater than or equal to the preset overcurrent threshold, and wakes up the system basis chip SBC; The system basis chip SBC wakes up the controller after being woken up. The controller enables the periodic cycle current monitoring circuit after being woken up by the system basis chip SBC. After being enabled, the periodic cycle current monitoring circuit continuously detects the current flowing through the high-side switch and sends the detection result to the controller.

10. The control method of the smart fuse control circuit according to claim 9, wherein: The preset wake-up time threshold is smaller than the preset sleep time threshold.

11. The control method of the smart fuse control circuit according to claim 9, wherein: When the current detection value sent by the periodic cycle current monitoring circuit is continuously less than the wake-up current threshold for a preset time period, the controller controls the system basis chip SBC to enter a sleep state and stops enabling the periodic cycle current monitoring circuit.

12. The control method of the smart fuse control circuit according to claim 9, wherein: The controller performs I2 protection and I3 protection according to the current detection result sent by the periodic cycle current monitoring circuit. 2 t protection.

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