Integrated circuit for battery disconnection unit

Abstract

The integrated circuit includes, for example, a first transistor connected to the first end of the coil of a DC contactor via a first pin, a second transistor connected to the second end of the coil of the DC contactor via a second pin, and a third pin to which an enable signal is input. The second transistor and the timer start operating based on the enable signal. The circuit provided in the integrated circuit increases the average current of the coil to a first target level in response to the start of operation of the second transistor, adjusts the average current to a second target level lower than the first target level in response to the elapsed time indicated by the timer, maintains the average current at the second target level until a disable signal is input to the third pin, and stops the operation of the second transistor in response to the input of the disable signal.

Description

Technical Field

[0001] The present disclosure relates to a battery disconnect unit.

Background Art

[0002] This specification relates to a battery disconnect unit (BDU) used, for example, in hybrid vehicles, plug-in hybrid vehicles, and battery electric vehicles. The battery disconnect unit is a type of high-voltage power distribution system and can be used as a primary interface between the vehicle's battery pack and the electrical system.

Summary of the Invention

[0003] The system addressed in this specification includes a battery disconnect unit (BDU) integrated circuit that enables efficient distribution of power throughout the electric vehicle system. The BDU integrated circuit can cause a DC contactor (direct current contactor) to connect and disconnect between the battery of the electric vehicle and various circuits of the electric vehicle by supplying power to the DC contactor. In some embodiments, the BDU integrated circuit can also monitor the current flowing through the coil of the contactor, generate a current delay, reduce the target current of the coil, and quickly cut off the current of the coil.

[0004] The system addressed in this specification includes a battery disconnect unit (BDU) integrated circuit that enables efficient distribution of power throughout the electric vehicle system. The BDU integrated circuit can cause a DC contactor (direct current contactor) to connect and disconnect between the battery of the electric vehicle and various circuits of the electric vehicle by supplying power to the DC contactor. In some embodiments, the BDU integrated circuit can also monitor the current flowing through the coil of the contactor, generate a current delay, reduce the target current of the coil, and promptly cut off the current of the coil.

[0005] According to one aspect of the present disclosure, the integrated circuit comprises a first transistor configured to be connected via a first pin to a first end of a coil of a DC contactor, and a second transistor configured to be connected via a second pin to a second end of the coil of the DC contactor. A third pin is configured to receive an enable signal, and the second transistor is configured to start operating based on this enable signal. A timer is also configured to start operating based on this enable signal. The integrated circuit also includes a circuit which, in response to the start of operation of the second transistor, increases the average current of the coil of the DC contactor to a first target level, adjusts the average current of the coil to a second target level lower than the first target level in response to the elapsed time indicated by the timer, maintains the average current of the coil at the second target level until a disable signal is input to the third pin, and stops the operation of the second transistor in response to the input of the disable signal.

[0006] Depending on the embodiment, it may have one or more of the following features.

[0007] In some embodiments, the second pin may be configured to receive a feedback signal, and the integrated circuit may include a circuit for monitoring the current in the coil of the DC contactor.

[0008] In some embodiments, the integrated circuit may further include a circuit configured to disconnect the second transistor from the coil of the DC contactor in response to the cessation of operation of the second transistor.

[0009] In some embodiments, the circuit configured to adjust the average current of the coil of the DC contactor to a second target level may include a circuit configured to adjust the duty cycle of the first transistor.

[0010] In some embodiments, the circuit configured to maintain the average current of the coil at the second target level may include a circuit configured to adjust the duty cycle of the first transistor.

[0011] In some embodiments, the circuit configured to increase the average current of the coil of the DC contactor to a first target level may include a circuit configured to compare the voltage corresponding to the current flowing through an external resistor that monitors the current of the coil with a reference voltage.

[0012] In some embodiments, the integrated circuit may be part of a device comprising: a vehicle circuit system; a DC contactor having a coil with a first and second end, configured to connect and disconnect a high-voltage battery from the vehicle circuit system; and the integrated circuit. The first transistor is configured to be connected to the first end of the coil of the DC contactor via the first pin, and the second transistor is configured to be connected to the second end of the coil of the DC contactor via the second pin. The device may further include a microcomputer configured to input the enable signal and the disable signal to the third pin.

[0013] According to other aspects of the present disclosure, a method for controlling the current flowing through a coil of a DC contactor includes the steps of: inputting an enable signal to an integrated circuit; starting a transistor and a timer in the integrated circuit in response to the input of the enable signal and connecting the started transistor to one end of the coil; increasing the average current of the coil to a first target level; adjusting the average current of the coil to a second target level lower than the first target level in response to the elapsed time based on the timer's timing; maintaining the average current of the coil at the second target level; inputting a disable signal to the integrated circuit; and stopping the transistor in response to the input of the disable signal.

[0014] Depending on the embodiment, the method may further include the step of disconnecting the integrated circuit from the coil in response to the cessation of operation of the second transistor.

[0015] In some embodiments, the step of adjusting the current of the coil to the second target level may include adjusting the duty cycle of the first transistor.

[0016] In some embodiments, the step of maintaining the average current of the coil at the second target level may include adjusting the duty cycle of the first transistor.

[0017] In some embodiments, the step of increasing the current in the coil to a first target level may include comparing the voltage corresponding to the current flowing through an external resistor that monitors the current in the coil with a reference voltage.

[0018] By implementing the contents disclosed herein in specific embodiments, one or more of the following effects can be obtained.

[0019] Conventional BDU units use discrete components and require a large number of passive elements and low-frequency components. By integrating the BDU function into an integrated circuit, the space occupied by the BDU on the printed circuit board (PCB) and the number of external passive elements can be reduced, while the operating frequency of the BDU can be increased.

[0020] Some embodiments of the disclosures herein will be described in detail below with reference to the accompanying figures. Other configurations, features, and effects will also become immediately apparent from the following detailed description, the accompanying figures, and the claims. [Brief explanation of the drawing]

[0021] [Figure 1] Figure 1 shows an example of an integrated circuit system 100 for electric vehicles.

[0022] [Figure 2] Figure 2 shows an example of a BDU system.

[0023] [Figure 3] Figure 3 is an example of a timing chart of the BDU system of Figure 2.

[0024] [Figure 4] Figure 4 is a flowchart showing an example of a method for controlling the current flowing through the coil of a DC contactor.

Embodiments for Carrying Out the Invention

[0025] Figure 1 shows an example of an integrated circuit system 100 for an electric vehicle. The electric vehicle is a hybrid vehicle, a plug-in hybrid vehicle, a battery electric vehicle, etc. The integrated circuit system 100 includes a voltage source 102 and a microcontroller 104 connected to a battery disconnect unit (BDU) 106 that can be implemented as an integrated circuit. The BDU integrated circuit 106 is connected to the coil 108 of a DC contactor 110. The DC contactor 110 controls the state of an electromechanical or other type of switch 114. That is, the DC contactor 110 is configured to connect and disconnect between a high-voltage battery 112 and one or more vehicle circuits 116 via the switch 114. One end of the switch 114 is connected to the high-voltage battery 112. When the switch 114 is in the closed state, the second end of the switch 114 is connected to the vehicle circuit 116. The vehicle circuit 116 may be any suitable circuit of the electric vehicle (e.g., an air conditioner compressor, a cabin heater, a traction inverter, etc.). When the switch 114 is in the open state, the second end of the switch 114 is disconnected from the vehicle circuit 116.

[0026] During operation, the voltage source 102 supplies a battery voltage to the BDU integrated circuit 106. The battery voltage may be a predetermined initial voltage, for example, 12V.

[0027] The microcontroller 104 automatically controls the BDU integrated circuit 106. The microcontroller 104 may include one or more CPUs, memory, and programmable input / output peripherals.

[0028] The BDU integrated circuit 106 supplies power to the DC contactor 110 by regulating the current flowing through the DC contactor coil 108. The BDU integrated circuit 106 functions as the primary interface between the vehicle's electrical system and the battery pack. In some cases, the BDU integrated circuit 106 is configured to efficiently distribute power throughout the electric vehicle system.

[0029] Figure 2 shows an example of a BDU system 200. This BDU system 200 comprises a voltage source 204, a BDU integrated circuit 202, and a DC contactor coil 246. The BDU integrated circuit 202 is illustrated in detail as a specific embodiment of the BDU integrated circuit 106 shown in Figure 1. The voltage source 204 is configured to supply an initial voltage to the BDU integrated circuit 202 via the input voltage pin 206 of the BDU integrated circuit. The voltage source 204 has a predetermined initial voltage, for example, 12V.

[0030] As shown in Figure 2, the BDU integrated circuit 202 includes a first transistor 218 configured to be connected to the first end of the coil 246 via a first pin 240, a second transistor 226 configured to be connected to the second end of the coil 246 via a second pin 238, a timer 232, and a third pin 212 configured to receive an enable signal. Both the second transistor 226 and the timer 232 are configured to start operating based on the enable signal. The first and second transistors can be any type of transistor, for example, a MOSFET.

[0031] During operation, the current in the DC contactor coil 246 is initially zero, and the first transistor 218 and the second transistor 226 are off. When an initial voltage is supplied from the voltage source 204 to the BDU integrated circuit 202 via the input voltage pin 206, the first transistor starts operating. The BDU integrated circuit 202 may include a circuit configured to turn on the first transistor 218. For example, the BDU integrated circuit 202 may include a flip-flop 216, the output of which can turn the first transistor 218 on / off. A buffer 250 may be provided between the output of the flip-flop 216 and the gate of the first transistor 218. As long as the second transistor 226 is off, even if the first transistor 218 is on, the current in the coil 246 remains zero.

[0032] Figure 3 shows an example of the timing chart 300 of the BDU shown in Figure 2. The timing chart includes voltage waveforms 372, enable signal waveforms 360, and coil current waveforms 362. Voltage waveform 372 represents the change in voltage at input voltage pin 206 over time. Enable signal waveform 360 represents the change in the enable signal at third pin 212 over time. Coil current waveform 362 represents the change in current in coil 246 over time. In the example shown, the initial values ​​of both voltage waveform 372 and coil current waveform 362 are zero, and the initial value of the enable signal waveform 360 is "low".

[0033] As shown in Figure 3, the voltage represented by the voltage waveform 372 increases when the initial voltage is supplied from the voltage source 204 to the BDU integrated circuit 202 at time A. For example, if the initial voltage is 12V, the voltage waveform 372 increases to 12V. Even when the initial voltage is supplied to the BDU integrated circuit 202 at time A, the coil current 362 initially remains zero.

[0034] Subsequently, when the enable signal (controlled by the microcontroller 104) goes high, the second transistor 226 and timer 232 start operating. The BDU integrated circuit 202 may include a circuit configured to increase the current of coil 246 to a predetermined first target level 366 in response to the start of operation of the second transistor 226. When the second transistor 226 starts operating, the current of coil 246 increases to the first target level 366. For example, in the illustrated example, the current of coil 246 increases to 2.2 amperes, which is a predetermined first target level 366. At time B, the enable signal goes "high". At time C, which is after time B, the coil current 362 reaches I1, which is the first target level 366. The coil current 362 remains at I1, which is the first target level 366, until time D.

[0035] To increase the current in coil 246 to a first target level, the BDU integrated circuit may include an error operational amplifier 228 that varies the on-time of the first transistor 218 as needed to bring the average current in coil 246 to the first target level. The error operational amplifier 228 is configured to compare a voltage corresponding to the current flowing through an external current-sense resistor 236 (which monitors the current in coil 246) with a reference voltage 230. In some embodiments, the reference voltage is 0.8 volts. The current flowing through the external current-sense resistor 236 corresponds to the coil current input via the second pin 238.

[0036] The BDU integrated circuit 202 may also include a circuit configured to maintain the average current of coil 246 at a first target level. A resistor connected to the output of timer 232 draws current from the non-inverting input of error op-amp 228, thereby causing the error op-amp 228 to saturate only when the current of coil 246 is at the first target level. The output of error op-amp 228 is connected to comparator op-amp 222, which is configured to adjust the duty cycle of first transistor 218 to maintain the average current of coil 246 at the first target level. Flip-flop 216 receives its input from oscillator 220 and comparator op-amp 222 to turn first transistor 218 on / off at a specified duty cycle.

[0037] In some embodiments, an inductor 252 is provided between the first transistor 218 and the coil 246. When the first transistor 218 is turned off, the voltage across the inductor 252 reverses. When the voltage across the inductor 252 reverses, the current in the inductor flows through the catch diode (freightback diode) 242. The inductor 252, along with the catch diode 242 and the capacitor 244, is configured to smooth the output at the first pin 240 before it reaches the coil 246.

[0038] The BDU integrated circuit 202 includes a circuit configured to adjust the coil current to a predetermined second target level in response to a timer indicating the elapsed of a predetermined time T. For example, in some embodiments, the predetermined time is 100 ms (milliseconds). The second target level is lower than the first target level. After the predetermined time has elapsed, the timer acts as a current source rather than a current sink. As a result, the error operational amplifier 228 determines that the current is too high and adjusts the duty cycle of the first transistor 218 to reduce the current in coil 246 to the second target level. For example, the comparator operational amplifier 222 adjusts the duty cycle of the first transistor 218 so that the current in coil 246 is at a predetermined second target level 368, for example, 0.55 amperes in the illustrated example. The coil current 362 remains at the first target level 366 for a predetermined time T, and then at time D, the coil current decreases to the second target level 368. In some embodiments, the respective values ​​of the predetermined first target level and the predetermined second target level may differ from those described above.

[0039] The BDU integrated circuit 202 is configured to maintain the average current of the coil 246 at a second target level until a disable signal is input via pin 212. Specifically, the comparator operational amplifier 222 maintains the current of the coil 246 at the second target level by adjusting the duty cycle of the first transistor 218.

[0040] When a disable signal is input via pin 212 (from the microcontroller 104), the second transistor 226 stops operating. The enable signal returns to "low" at time E, and the coil current 362 decreases to zero.

[0041] When the second transistor 226 stops operating, a voltage spike may occur. The BDU integrated circuit 202 may include a Zener diode 224 connected between the drain and gate of the second transistor 226. The diode 224 keeps the second transistor 226 on until the current decreases and the voltage becomes zero. In other words, the diode 224 prevents the drain voltage of the second transistor 226 from reaching an avalanche state when the first transistor 218 turns off. This allows the contactor to quickly disconnect, preventing damage to the second transistor 226 from a voltage spike. More specifically, when the circuit stops the second transistor 226 from operating, the energy in the coil 246 is released, and the DC contactor quickly opens. The lower end of the coil 246 transitions to a positive voltage, generating a high voltage at the drain of the second transistor 226. The Zener diode 224 prevents the drain voltage from rising to an avalanche state by limiting the upper limit of the rise in the drain voltage 234. As a result, the second transistor 226 quickly stops operating, and the DC contactor becomes open without damage.

[0042] In some embodiments, the BDU integrated circuit 202 includes a fourth pin 210 connected to the error operational amplifier 228. In some embodiments, compensation may be provided to keep the system 200 stable. The fourth pin 210 may optionally be connected to control the gain of the error operational amplifier 228, for example, by connecting a resistor or capacitor.

[0043] In some embodiments, the BDU integrated circuit 202 includes a fifth pin 208 connected to an oscillator 220. The fifth pin 208 can receive a signal to set the operating frequency of the first transistor 218 to a fixed value. The oscillator 220 is connected to a comparator operational amplifier 222 and to the input of a flip-flop 216. The oscillator 220 generates a ramp signal to a slope circuit 248. The comparator operational amplifier 222 is controlled by the intersection of the ramp signal and the output of an error operational amplifier 228.

[0044] In some embodiments, the BDU integrated circuit 202 includes a circuit configured to detect the current flowing through the first transistor 218. The current flowing through the first transistor 218 can be sampled by a current sensor 214. In some embodiments, sampling the current can protect the BDU integrated circuit 202 from overcurrent conditions when the load is short-circuited. As one example, the sampled current is combined with a slope 248 and supplied to a comparator operational amplifier 222.

[0045] The flowchart in Figure 4 shows an example of a method 400 for controlling the current flowing through the coil of a DC contactor. This method 400 can be implemented by any suitable system, for example, by the BDU system 200 shown in Figure 2, which includes a coil of a DC contactor and an integrated circuit 202. The ends of the coil are connected to different transistors in the integrated circuit, respectively. The first transistor may start operating before the enable signal is input. If only the first transistor starts operating, the current in the coil is zero. When both the first and second transistors start operating, current flows through the coil.

[0046] In step 402, an enable signal is input to the integrated circuit. In response to the input of the enable signal, the system causes the second transistor and timer in the integrated circuit to start operating (404). Once started, the second transistor is connected to the coil of the DC contactor.

[0047] When the second transistor starts operating, the average current of the coil increases to a predetermined first target level (e.g., 2.2 amperes) (406). The system maintains the average current of the coil at the first target level. Based on the timer, after a predetermined time has elapsed, the system adjusts the current of the coil to a predetermined second target level (e.g., 0.55 amperes) (408). Here, the second target level is lower than the first target level. The system maintains the average current of the coil at the second target level (410).

[0048] Subsequently, a disable signal is input to the integrated circuit (412). In response to the input of the disable signal, the second transistor stops operating (414). As a result, the energy stored in the coil is rapidly released, and the contactor rapidly opens. The lower end of the coil transitions to a positive voltage, which generates a high voltage at the drain of the second transistor. The system may include, for example, a Zener diode to prevent the voltage from reaching an avalanche state. This configuration, depending on the embodiment, can avoid damage to the second transistor. The rapid opening of the contactor prevents arc discharge between components.

[0049] Although several specific embodiments of the present invention have been described above, these are illustrative and various modifications are possible, as long as they do not exceed the technical spirit or scope of the disclosure. Therefore, other embodiments may also fall within the scope of the claims.

Claims

1. A first transistor is configured to be connected to the first end of the coil of a DC contactor via a first pin, A second transistor is configured to be connected to the second end of the coil of the DC contactor via a second pin, The second transistor is configured to start operating based on an enable signal, and a third pin is configured to receive the enable signal, A timer configured to start operating based on the enable signal, Circuits and, Equipped with, The aforementioned circuit In response to the start of operation of the second transistor, the average current of the coil of the DC contactor is increased to a first target level. In response to the elapsed time indicated by the timer, the average current of the coil is adjusted to a second target level lower than the first target level. The average current of the coil is maintained at the second target level until a disable signal is input to the third pin. The second transistor is stopped from operating in response to the input of the disable signal. Integrated circuit.

2. The second pin is configured to receive a feedback signal. The integrated circuit includes a circuit for monitoring the current of the coil of the DC contactor. The integrated circuit according to claim 1.

3. The circuit further comprises a circuit configured to disconnect the second transistor from the coil of the DC contactor in response to the cessation of operation of the second transistor. The integrated circuit according to claim 1 or claim 2.

4. The circuit configured to adjust the average current of the coil of the DC contactor to the second target level includes a circuit configured to adjust the duty cycle of the first transistor. The integrated circuit according to any one of claims 1 to 3.

5. The circuit configured to maintain the average current of the coil at the second target level includes a circuit configured to adjust the duty cycle of the first transistor. The integrated circuit according to any one of claims 1 to 3.

6. The circuit configured to increase the average current of the coil of the DC contactor to a first target level includes a circuit configured to compare the voltage corresponding to the current flowing through an external resistor that monitors the current of the coil with a reference voltage. The integrated circuit according to any one of claims 1 to 5.

7. The vehicle's circuitry and, A DC contactor comprising a coil having a first end and a second end, configured to connect and disconnect between a high-voltage battery and the vehicle's circuit system, The integrated circuit according to claim 1, Equipped with, The first transistor is configured to be connected to the first end of the coil of the DC contactor via the first pin, The second transistor is configured to be connected to the second end of the coil of the DC contactor via the second pin. Device.

8. The microcomputer further comprises a microcomputer configured to input the enable signal and the disable signal to the third pin. The apparatus according to claim 7.

9. A method for controlling the current flowing through the coil of a DC contactor, The steps include inputting an enable signal to the integrated circuit, The steps include: starting the operation of the transistor and timer in the integrated circuit in response to the input of the enable signal, and connecting the started transistor to one end of the coil; The steps include increasing the average current of the coil to a first target level, A step of adjusting the average current of the coil to a second target level lower than the first target level in response to the elapsed time based on the timer's timing, The steps include maintaining the average current of the coil at the second target level, The steps include inputting a disable signal to the integrated circuit, A step of stopping the operation of the transistor in response to the input of a disable signal, including, method.

10. The further step includes disconnecting the integrated circuit from the coil in response to the cessation of operation of the second transistor. The method according to claim 9.

11. The step of adjusting the current of the coil to the second target level includes adjusting the duty cycle of the first transistor. The method according to claim 9 or claim 10.

12. The step of maintaining the average current of the coil at the second target level includes adjusting the duty cycle of the first transistor. The method according to claim 9 or claim 10.

13. The step of increasing the current in the coil to the first target level includes comparing the voltage corresponding to the current flowing through an external resistor that monitors the current in the coil with a reference voltage. The method according to any one of claims 9 to 12.

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