Switch device, electronic equipment, and vehicle

Abstract

A switch device 1 includes, for example, a power supply terminal T1 to which a power supply voltage VBB is supplied, an output terminal T2 to which a load is externally connected, a switch element 10 connected between the power supply terminal T1 and the output terminal T2, a signal output terminal T5 that outputs an output current detection signal Vs corresponding to an output current Io flowing during the ON period of the switch element 10 (IN = H), an overcurrent protection circuit 71 that limits the output current detection signal Vs to or below a predetermined overcurrent limit value Vocp during the ON period of the switch element 10 (IN = H), and an output abnormality detection circuit 72 that monitors the output voltage Vo of the output terminal T2 in a first state (SEN=L) in which no current is supplied to the output terminal T2 during the OFF period (IN = L) of the switching element 10 and a second state (SEN = H) in which the current is supplied to the output terminal T2, while switching the states, to switch the logic level of the output current detection signal Vs.

Description

Switching devices, electronic devices, vehicles

[0001] The invention disclosed in this specification relates to a switch device, and an electronic device and a vehicle using the same.

[0002] The applicant of the present application has previously proposed many new technologies relating to switching devices such as in-vehicle intelligent power devices (IPDs) (see, for example, Patent Document 1).

[0003] International Publication No. 2017 / 187785

[0004] However, in the conventional switch device, there is room for further improvement in determining whether an output is in an abnormal state (particularly in terms of the trade-off with an increased number of terminals).

[0005] For example, a switch device disclosed in this specification includes a power supply terminal configured to receive a power supply voltage, an output terminal configured to receive an external load, a switch element configured to be connected between the power supply terminal and the output terminal, a signal output terminal configured to output an output current detection signal corresponding to an output current flowing during an on-period of the switch element, an overcurrent protection circuit configured to limit the output current detection signal to a predetermined overcurrent limit value or less during the on-period of the switch element, and an output abnormality detection circuit configured to switch between a first state in which no current is supplied to the output terminal and a second state in which current is supplied to the output terminal during an off-period of the switch element, monitor the output voltage of the output terminal in each state, and switch the logic level of the output current detection signal.

[0006] Still other features, elements, steps, advantages, and characteristics will become more apparent from the detailed description that follows and the accompanying drawings related thereto.

[0007] According to the invention disclosed in this specification, it is possible to provide a switch device that can determine an abnormal output state while suppressing an increase in the number of terminals, as well as an electronic device and a vehicle that use the same.

[0008] FIG. 1 is a diagram showing the overall configuration of a semiconductor integrated circuit device. FIG. 2 is a diagram showing an example of the configuration of an output abnormality detection circuit. FIG. 3 is a diagram showing an example of an output abnormality detection operation. FIG. 4 is a diagram showing an example of an output current detection signal when IN=H. FIG. 5 is a diagram showing an example of an output current detection signal when IN=L. FIG. 6 is a diagram showing the external appearance of a vehicle.

[0009] 1 is a diagram showing the overall configuration of a semiconductor integrated circuit device 1. In this configuration example, the semiconductor integrated circuit device 1 is an in-vehicle high-side switch LSI (a type of in-vehicle IPD) that establishes / shuts conduction between an application terminal of a power supply voltage VBB and a load 3 in response to instructions from an ECU (electronic control unit) 2 (corresponding to a control device).

[0010] The semiconductor integrated circuit device 1 includes external terminals T1 to T7 as means for establishing electrical connection with the outside of the device. The external terminal T1 is a power supply terminal for receiving a power supply voltage VBB (e.g., 12 V) from a battery (not shown). The external terminal T2 is a load connection terminal or output terminal for externally connecting a load 3 (such as a bulb lamp, a relay coil, a solenoid, a light-emitting diode, or a motor).

[0011] The external terminals T3 and T4 are signal input terminals for receiving external inputs of an external control signal IN and an external enable signal SEN from the ECU 2, respectively. The external terminal T5 is a signal output terminal for externally outputting an output current detection signal Vs to the ECU 2. A resistor 4 is externally connected between the external terminal T5 and a ground terminal. The external terminal T6 is a soft start control terminal. A resistor 5 for adjusting the soft start time is externally connected between the external terminal T5 and a ground terminal. The external terminal T7 is a ground terminal.

[0012] Referring to the figure, the semiconductor integrated circuit device 1 is configured by integrating NMOSFETs (N-channel type metal oxide semiconductor field effect transistors) 10 and 20, a gate control unit 30, a control logic unit 40, signal input units 51 and 52, an internal power supply unit 60, an abnormality protection unit 70, and a soft-start control unit 80.

[0013] The NMOSFET 10 is a high-voltage (e.g., 42 V) power transistor with its drain connected to the external terminal T1 and its source connected to the external terminal T2. Connected in this manner, the NMOSFET 10 functions as a switch element (high-side switch) for connecting / disconnecting a current path from the application terminal of the power supply voltage VBB to the ground terminal via the load 3. The NMOSFET 10 is turned on when the gate drive signal G1 is at a high level, and turned off when the gate drive signal G1 is at a low level.

[0014] Furthermore, the NMOSFET 10 may be designed so that its on-resistance Ron is several tens of milliohms. However, the lower the on-resistance Ron of the NMOSFET 10, the more likely an overcurrent will flow and abnormal heat will be generated when a ground fault occurs at the external terminal T2. A ground fault refers to a short circuit to the ground terminal or an equivalent low-potential terminal. Therefore, the lower the on-resistance Ron of the NMOSFET 10, the more important the overcurrent protection circuit 71 and the temperature protection circuit 73 (described below) become.

[0015] The NMOSFET 20 is a current detection element (so-called mirror transistor) whose gate is connected in common with the NMOSFET 10. The NMOSFET 20 generates a sense current Is corresponding to the output current Io flowing through the NMOSFET 10. The size ratio between the NMOSFET 10 and the NMOSFET 20 is m:1 (where m > 1). Therefore, the sense current Is is 1 / m of the output current Io. Like the NMOSFET 10, the NMOSFET 20 is turned on when the gate drive signal G1 is at a high level and turned off when the gate voltage G1 is at a low level.

[0016] The gate control unit 30 generates a gate drive signal G1 with an increased current capability of the gate control signal S1 and outputs the signal to the gates of the NMOSFETs 10 and 20, thereby controlling the on / off of the NMOSFETs 10 and 20.

[0017] Referring to the figure, the gate control unit 30 includes a gate driver 31 , an oscillator 32 , a charge pump 33 , a current detection circuit 34 , and an active clamp circuit 35 .

[0018] The gate driver 31 operates by receiving a boosted voltage VG from the charge pump 33, and generates a gate drive signal G1 that has an increased current capability compared to the gate control signal S1. The gate drive signal G1 is at a high level (=VG) when the gate control signal S1 is at a high level, and is at a low level (=Vo) when the gate control signal S1 is at a low level.

[0019] The oscillator 32 generates a clock signal CLK of a predetermined frequency and outputs it to the charge pump 33. The operation of the oscillator 32 is controlled in response to an internal enable signal Sa from the control logic unit 40.

[0020] The charge pump 33 is an example of a booster unit that generates a boosted voltage VG higher than the power supply voltage VBB by driving a flying capacitor using a clock signal CLK and supplies the boosted voltage VG to the gate driver 31. Whether the charge pump 33 is operable is controlled in accordance with an internal enable signal Sb from the control logic unit 40.

[0021] The current detection circuit 34 outputs a sense current Is (=Io / m) corresponding to the output current Io to the external terminal T5. Therefore, the ECU 2 basically receives an output current detection signal Vs (=Is×Rs) obtained by current-to-voltage conversion of the sense current Is using a resistor 4 (resistance value: Rs). The output current detection signal Vs increases as the output current Io increases, and decreases as the output current Io decreases. To read the value of the output current Io from the output current detection signal Vs, the ECU 2 simply performs analog-to-digital (A / D) conversion on the output current detection signal Vs.

[0022] The active clamp circuit 35 is connected between the gate of the NMOSFET 10 and the ground terminal. In an application in which an inductive load 3 is connected to the external terminal T2, when the NMOSFET 10 is switched from on to off, the output voltage Vo becomes a negative voltage (Vo<GND) due to the back electromotive force of the load 3. For this reason, the active clamp circuit 35 is provided for energy absorption. The active clamp circuit 35 limits the drain-source voltage of the NMOSFET 10 (=VBB-Vo) to an active clamp voltage Vclp or less by not fully turning off the NMOSFET 10 when the NMOSFET 10 transitions to off. Note that the active clamp voltage Vclp may be set with the ground potential GND as a reference.

[0023] The control logic unit 40 receives the external control signal IN and the external enable signal SEN and generates the gate control signal S1 and the internal enable signals Sa and Sb. For example, the control logic unit 40 sets the gate control signal S1 to a high level when the external control signal IN is at a high level (= the logic level when turning on the NMOSFET 10). On the other hand, the control logic unit 40 sets the gate control signal S1 to a low level when the external control signal IN is at a low level (= the logic level when turning off the NMOSFET 10). The control logic unit 40 also monitors various output signals from the abnormality protection unit 70.

[0024] The signal input units 51 and 52 are Schmitt triggers that receive an external control signal IN and an external enable signal SEN input from external terminals T3 and T4, respectively, and transmit them to the control logic unit 40 and the internal power supply unit 60.

[0025] The internal power supply unit 60 generates a predetermined internal power supply voltage Vreg from the power supply voltage VBB and supplies it to each component of the semiconductor integrated circuit device 1. The operation of the internal power supply unit 60 is controlled in accordance with an external control signal IN and an external enable signal SEN. For example, the internal power supply unit 60 is in an operating state when both the external control signal IN and the external enable signal SEN are at a high level, and is in an inoperable state when at least one of the external control signal IN and the external enable signal SEN is at a low level.

[0026] The fault protection unit 70 is a circuit block that detects various faults in the semiconductor integrated circuit device 1. Referring to the figure, the fault protection unit 70 includes an overcurrent protection circuit 71, an output fault detection circuit 72, a temperature protection circuit 73, and an undervoltage protection circuit 74.

[0027] The overcurrent protection circuit 71 generates an overcurrent protection signal S71 according to the monitoring result of the output current detection signal Vs (i.e., whether or not an overcurrent abnormality has occurred in the output current Io). The overcurrent protection signal S71 is, for example, at a low level when no abnormality is detected and at a high level when an abnormality is detected. When the overcurrent protection signal S71 is at a high level, the gate control signal S1 may be pulled down so as to suppress the output current Io.

[0028] The output abnormality detection circuit 72 generates an output abnormality detection signal S72 according to the monitoring result of the output voltage Vo (i.e., whether or not a load open circuit or a short circuit to the power supply has occurred at the external terminal T2). A short circuit to the power supply refers to a short circuit to the application terminal of the power supply voltage VBB or an equivalent high potential terminal. The output abnormality detection signal S72 is, for example, low level when no abnormality is detected, and high level when an abnormality is detected.

[0029] The temperature protection circuit 73 includes a temperature detection element (not shown) that detects abnormal heat generation in the semiconductor integrated circuit device 1 (particularly in the vicinity of the NMOSFET 10), and generates a temperature protection signal S73 according to the detection result (i.e., whether or not abnormal heat generation is occurring). The temperature protection signal S73, for example, goes low when no abnormality is detected, and goes high when an abnormality is detected.

[0030] The undervoltage protection circuit 74 generates an undervoltage protection signal S74 according to the monitoring result of the power supply voltage VBB or the internal power supply voltage Vreg (i.e., whether or not an undervoltage abnormality has occurred). The undervoltage protection signal S74 is, for example, at a low level when no abnormality is detected, and at a high level when an abnormality is detected.

[0031] The soft start control unit 80 gradually raises the gate control signal S1 over a predetermined soft start time Tss to prevent an excessively large output current Io from flowing when the semiconductor integrated circuit device 1 is started up. The soft start time Tss may be arbitrarily adjustable using a resistor 5 externally attached to the external terminal T6.

[0032] <Considerations Regarding the Number of Terminals> Incidentally, the semiconductor integrated circuit device 1 has a gain adjustment function for the output current detection signal Vs (and therefore a function for adjusting the overcurrent limit value Vocp) using a resistor 4 in order to apply appropriate overcurrent protection according to the load 3. When this configuration is adopted, an external terminal T5 for externally connecting the resistor 4 to the semiconductor integrated circuit device 1 is required.

[0033] Furthermore, in automotive applications, it may be necessary to distinguish between abnormal modes (for example, output ground fault, output short to power, and open circuit). For this reason, some conventional semiconductor integrated circuit devices use one enable input terminal and two diagnostic output terminals to switch between abnormal modes.

[0034] However, if all of the above functions are to be incorporated into the semiconductor integrated circuit device 1 without any ingenuity, the number of terminals of the semiconductor integrated circuit device 1 will increase, which will result in an increase in the product price of the semiconductor integrated circuit device 1.

[0035] In view of the above considerations, a novel embodiment will be proposed below that makes it possible to determine whether the output of the semiconductor integrated circuit device 1 is in an abnormal state while suppressing an increase in the number of terminals.

[0036] 2 is a diagram showing an example of the configuration of the output abnormality detection circuit 72. The output abnormality detection circuit 72 in this example configuration includes a current source 72A, resistors 72B and 72C, a comparator 72D, an enable control unit 72E, and a signal output unit 72F.

[0037] The current source 72A is connected between the external terminal T1 (= power supply terminal to which the power supply voltage VBB is applied) and the external terminal T2 (= output terminal to which the output voltage Vo is applied), and generates a current IA to be supplied to the external terminal T2. The enable / disable state of the current source 72A is switched in response to the internal enable signal EN1. The current source 72A does not necessarily have to be a constant current source as shown in the figure. For example, the current source 72A may be configured such that a resistor and a switch are connected in series between the external terminal T1 and the external terminal T2, and the switch is turned on / off in response to the internal enable signal EN1.

[0038] The resistors 72B and 72C are connected in series between the external terminal T2 and the ground terminal. The resistors 72B and 72C connected in this manner function as a voltage divider that outputs a monitoring voltage Vx (= a divided voltage of the output voltage Vo) corresponding to the output voltage Vo from a connection node between them. Note that if the output voltage Vo is within the input dynamic range of the comparator 72D, the resistors 72B and 72C may be omitted, and the output voltage Vo may be directly input to the comparator 72D as the monitoring voltage Vx.

[0039] The comparator 72D compares a monitoring voltage Vx input to its non-inverting input terminal (+) with a predetermined threshold voltage Vy input to its inverting input terminal (-) to generate an output abnormality detection signal S72D and output it to the signal output unit 72F. Therefore, the output abnormality detection signal S72D goes high when Vx > Vy and goes low when Vx < Vy. The comparator 72D is enabled or disabled in response to the internal enable signal EN2.

[0040] The enable control section 72E generates internal enable signals EN1 and EN2 in response to an external control signal IN (corresponding to an on / off control signal for the NMOSFET 10) and an external enable signal SEN input from external terminals T3 and T4, respectively.

[0041] For example, when IN=L and SEN=L, the enable control unit 72E disables the current source 72A and enables the comparator 72D. Also, when IN=L and SEN=H, the enable control unit 72E enables both the current source 72A and the comparator 72D. Also, when IN=H, the enable control unit 72E disables both the current source 72A and the comparator 72D.

[0042] That is, during the off period (IN=L) of NMOSFET 10, enable control unit 72E enables comparator 72D and generates internal enable signals EN1 and EN2 to switch the enable / disable status of current source 72A according to the external enable signal SEN.

[0043] The output abnormality detection circuit 72 configured in this manner switches between a first state (SEN=L) in which no current is supplied to the external terminal T2 and a second state (SEN=H) in which current is supplied to the external terminal T2 during the off period (IN=L) of the NMOSFET 10, and monitors the output voltage Vo in each state to generate an output abnormality detection signal S72D.

[0044] The signal output unit 72F is a circuit block configured to output the output abnormality detection result of the external terminal T2 using the external terminal T5 (= signal output terminal that outputs an output current detection signal Vs corresponding to the output current Io).

[0045] Referring to this figure, the signal output section 72F is configured to switch the logic level of the output current detection signal Vs in response to the output abnormality detection signal S72D generated while the NMOSFET 10 is off (IN=L).

[0046] For example, the signal output unit 72F operates so as to set the output current detection signal Vs to a low level when the output abnormality detection signal S72D is at a low level, and to set the output current detection signal Vs to a high level when the output abnormality detection signal S72D is at a high level during the off period (IN=L) of the NMOSFET 10. In other words, the output current detection signal Vs is not an analog signal corresponding to the output current Io, but is a digital signal equivalent to the output abnormality detection signal S72D.

[0047] In this way, the output abnormality detection circuit 72 of this configuration example switches between a first state in which no current is supplied to the external terminal T2 and a second state in which current is supplied to the external terminal T2 during the off period (IN=L) of the NMOSFET 10, and monitors the output voltage Vo of the external terminal T2 in each state to switch the logic level of the output current detection signal Vs.

[0048] Moreover, the overcurrent protection circuit 71 limits the output current detection signal Vs to a predetermined overcurrent limit value Vocp or less during the ON period of the NMOSFET 10 (IN=H).

[0049] Furthermore, the temperature protection circuit 73 switches the logic level of the output current detection signal Vs depending on whether or not abnormal heat generation is occurring in the semiconductor integrated circuit device 1 (particularly the NMOSFET 10). For example, when abnormal heat generation is occurring in the semiconductor integrated circuit device 1, the temperature protection circuit 73 may raise the output current detection signal Vs to an abnormal heat generation detection value Vtsd that is higher than the overcurrent limit value Vocp.

[0050] In this way, in the semiconductor integrated circuit device 1, the external terminal T5, which is provided as the output terminal for the output current detection signal Vs, is also used as the output terminal for the output abnormality detection result. With this configuration example, it is possible to determine an output abnormality state while suppressing an increase in the number of terminals. The output abnormality detection operation will be described in detail below.

[0051] 3 is a diagram showing an example of the output abnormality detection operation, particularly showing the output state (OUT) of the external terminal T2, the external control signal IN, the external enable signal SEN, the output current detection signal Vs, and the abnormality determination result.

[0052] First, a case where the external terminal T2 is in a normal state (i.e., a state where neither an open load, a short to power, nor a short to ground occurs) will be described.

[0053] During the off-period of the NMOSFET 10 (IN=L), no output current Io flows through the external terminal T2. Furthermore, the output voltage Vo is approximately equal to the ground potential GND. Therefore, the output current detection signal Vs is at a low level, regardless of the logic level of the external enable signal SEN. At this time, the ECU 2, which receives the output current detection signal Vs, determines that the NMOSFET 10 is in the off state.

[0054] On the other hand, during the on-period of the NMOSFET 10 (IN=H), an appropriate output current Io flows from the external terminal T2 to the load 3. Therefore, the output current detection signal Vs is in a state where it is output as an analog signal in accordance with the output current Io (Vs=Is×Rs). Note that unless the output current Io is in an overcurrent state, the output current detection signal Vs varies within a range lower than the overcurrent limit value Vocp. In this case, the ECU 2 receiving the output current detection signal Vs determines that the output current is in the output current detection state (i.e., the output current Io is flowing normally without being limited).

[0055] Next, a case where the external terminal T2 is in an open load state (Open Load) will be described.

[0056] During the off period of the NMOSFET 10 (IN=L), when SEN=L, the current source 72A is disabled. This results in a first state in which no current IA is supplied to the external terminal T2. Here, when the external terminal T2 is in an open-load state, the external terminal T2 is pulled down via resistors 72B and 72C (or the resistance component Rx of the internal circuit connected to the source of the NMOSFET 10). Therefore, the output voltage Vo becomes approximately equal to the ground potential GND. As a result, Vx<Vy, and S72D=L (and therefore Vs=L).

[0057] On the other hand, when SEN=H during the off period of the NMOSFET 10 (IN=L), the current source 72A is enabled. Therefore, a second state is established in which a current IA is supplied to the external terminal T2. When the external terminal T2 is in an open-load state, the output voltage Vo becomes a potential (Vo=IA×RA, where RA is the combined resistance of the resistors 72B and 72C) corresponding to the resistors 72B and 72C (or resistance components, not shown, associated with the external terminal T2 and the ground terminal) and the current IA. Therefore, if the current IA and the combined resistance RA are appropriately set, Vx>Vy, and S72D=H (and therefore Vs=H).

[0058] In this way, when the external terminal T2 is in an open load state, during the off period (IN=L) of the NMOSFET 10, the output current detection signal Vs becomes low level when in the first state (SEN=L), and becomes high level when in the second state (SEN=H).

[0059] Therefore, the ECU 2 that receives the input of the output current detection signal Vs can determine that the external terminal T2 is in an open load state if the output current detection signal Vs is at a low level when the NMOSFET 10 is in the first state (SEN=L) during the off period (IN=L) and is at a high level when the NMOSFET 10 is in the second state (SEN=H).

[0060] When the external terminal T2 is in an open load state, only a minute output current Io (=VBB / (Ron+Rx), where Rx>>Ron) flows through the NMOSFET 10 during the on period (IN=H) of the NMOSFET 10. Furthermore, the output voltage Vo (=VBB-Ron×Io) is approximately equal to the power supply voltage VBB.

[0061] As a result, the output current detection signal Vs becomes low regardless of the logic level of the external enable signal SEN. This state is no different from when the external terminal T2 is in a short-to-power state (details will be described later). Therefore, even if the ECU 2 monitors the output current detection signal Vs while the NMOSFET 10 is on (IN=H), it cannot determine whether the abnormality occurring at the external terminal T2 is an open load or a short-to-power state.

[0062] Next, a case where the external terminal T2 is in a power short state (VBB Short) will be described.

[0063] During the off period of the NMOSFET 10 (IN=L), when SEN=L, the current source 72A is disabled. This results in a first state in which no current IA is supplied to the external terminal T2. Here, if the external terminal T2 is in a power short state, the output voltage Vo becomes approximately equal to the power supply voltage VBB. Therefore, Vx>Vy, and therefore S72D=H (and therefore Vs=H).

[0064] On the other hand, when SEN=H during the off period of NMOSFET 10 (IN=L), current source 72A is enabled. This results in a second state in which current IA is supplied to external terminal T2. If external terminal T2 is shorted to the power supply, output voltage Vo will also be approximately equal to power supply voltage VBB. Therefore, Vx>Vy, and S72D=H (and therefore Vs=H).

[0065] In this way, when the external terminal T2 is in a power short state, the output current detection signal Vs becomes high level in both the first state (SEN=L) and the second state (SEN=H) during the off period of the NMOSFET 10 (IN=L).

[0066] Therefore, the ECU 2 that receives the input of the output current detection signal Vs can determine that the external terminal T2 is in a power short state if the output current detection signal Vs is at a high level in both the first state (SEN=L) and the second state (SEN=H) during the off period (IN=L) of the NMOSFET 10.

[0067] When the external terminal T2 is in a short-to-power state, a short-circuit path is formed that directly connects the application terminal of the power supply voltage VBB to the load 3. The resistance component Ry of this short-circuit path is very small (Ry = several mΩ to several tens of mΩ). Therefore, during the on-period (IN = H) of the NMOSFET 10, most of the current flowing from the application terminal of the power supply voltage VBB to the load 3 flows through the short-circuit path as the power-fault current Ivbbs, and almost no output current Io flows through the NMOSFET 10. Furthermore, the output voltage Vo (= VBB - Ry × Ivbbs) is approximately the power supply voltage VBB.

[0068] As a result, the output current detection signal Vs becomes low regardless of the logic level of the external enable signal SEN. This state is no different from the open load state described above. Therefore, even if the ECU 2 monitors the output current detection signal Vs while the NMOSFET 10 is on (IN=H), it cannot determine whether the abnormality occurring at the external terminal T2 is an open load or a short to power.

[0069] Next, a case where the external terminal T2 is in a ground short state (GND Short) will be described.

[0070] Even if the external terminal T2 is in a grounded state, no output current Io flows through the external terminal T2 during the off-period (IN=L) of the NMOSFET 10. Furthermore, the output voltage Vo is approximately equal to the ground potential GND. Therefore, the output current detection signal Vs is at a low level regardless of the logic level of the external enable signal SEN. At this time, the ECU 2, which receives the output current detection signal Vs, determines that the NMOSFET 10 is in an off-state. This determination operation is the same as when the external terminal T2 is in a normal state.

[0071] On the other hand, during the on-period (IN=H) of the NMOSFET 10, an excessively large output current Io flows through the NMOSFET 10 via the ground-fault path of the external terminal T2. At this time, the output current detection signal Vs is limited to be equal to or less than the overcurrent limit value Vocp by the action of the overcurrent protection circuit 71.

[0072] Therefore, the ECU 2 that receives the input of the output current detection signal Vs can determine that there is a ground fault state or an overcurrent limit state when the output current detection signal Vs is maintained at the overcurrent limit value during the on period of the NMOSFET 10 (IN = H).

[0073] 4 is a diagram showing an example of the output current detection signal Vs during the on-period (IN=H) of the NMOSFET 10. The vertical axis of this diagram represents the output current detection signal Vs, and the horizontal axis of this diagram represents the sense current Is.

[0074] The ECU 2 determines that the output current detection state (i.e., normal state) is established when, during the on-period (IN=H) of the NMOSFET 10, the output current detection signal Vs is not fixed to a low level and is output as an analog signal in a voltage range lower than the overcurrent limit value Vocp.

[0075] Furthermore, the ECU 2 determines that a ground fault or an overcurrent limit state exists when the output current detection signal Vs is maintained at the overcurrent limit value Vocp during the ON period of the NMOSFET 10 (IN=H).

[0076] Furthermore, the ECU 2 determines that an abnormal heat generation state (TSD) has occurred when the output current detection signal Vs is raised to an abnormal heat generation detection value Vtsd, which is higher than the overcurrent limit value Vocp, due to the action of the temperature protection circuit 73 during the on-period (IN=H) of the NMOSFET 10.

[0077] 5 is a diagram showing an example of the output current detection signal Vs during the off period (IN=L) of the NMOSFET 10. The vertical axis of this diagram represents the output current detection signal Vs, and the horizontal axis of this diagram represents the output voltage Vo.

[0078] During the off period (IN=L) of NMOSFET 10, when the output current detection signal Vs is at a low level regardless of whether the external enable signal SEN is at a low level or a high level, ECU 2 determines that NMOSFET 10 is in an off state (however, it does not matter whether the external terminal T2 is in a normal state or a ground fault state).

[0079] Furthermore, during the off period (IN=L) of NMOSFET 10, ECU 2 determines that external terminal T2 is in an open load state when the output current detection signal Vs is at a low level when the external enable signal SEN is at a low level, and when the output current detection signal Vs is at a high level when the external enable signal SEN is at a high level.

[0080] Furthermore, during the off period (IN=L) of NMOSFET 10, when the output current detection signal Vs is at a high level regardless of whether the external enable signal SEN is at a low level or a high level, ECU 2 can determine that the external terminal T2 is in a power short state.

[0081] <Application to Vehicles> Fig. 6 is a diagram showing the exterior of a vehicle X. The vehicle X of this configuration example is equipped with various electronic devices that operate on power supplied from a battery.

[0082] Vehicle X includes not only engine vehicles but also electric vehicles (battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs / PHVs), or xEVs such as fuel cell electric vehicles (FCEVs / FCVs)).

[0083] The semiconductor integrated circuit device 1 described above can be incorporated into any of the electronic devices mounted on the vehicle X.

[0084] <Summary> The various embodiments described above will be summarized below.

[0085] For example, a switch device disclosed in this specification is configured (first configuration) to include: a power supply terminal configured to receive a power supply voltage; an output terminal configured to receive an external load; a switch element configured to be connected between the power supply terminal and the output terminal; a signal output terminal configured to output an output current detection signal corresponding to an output current flowing during an on-period of the switch element; an overcurrent protection circuit configured to limit the output current detection signal to a predetermined overcurrent limit value or less during the on-period of the switch element; and an output abnormality detection circuit configured to switch between a first state in which no current is supplied to the output terminal and a second state in which current is supplied to the output terminal during an off-period of the switch element, monitor the output voltage of the output terminal in each state, and switch the logic level of the output current detection signal.

[0086] In the switch device according to the first configuration, the output abnormality detection circuit may be configured (second configuration) to include: a current source configured to generate a current to be supplied to the output terminal; a comparator configured to compare a monitoring voltage corresponding to the output voltage with a predetermined threshold voltage to generate an output abnormality detection signal; an enable control unit configured to enable the comparator during the off period of the switch element and switch between enabling and disabling the current source; and a signal output unit configured to switch the logic level of the output current detection signal according to the output abnormality detection signal.

[0087] Furthermore, in the switch device according to the second configuration, the output abnormality detection circuit may be configured to further include a voltage divider configured to divide the output voltage to generate the monitoring voltage (third configuration).

[0088] Furthermore, the switch device according to any one of the first to third configurations may be configured (fourth configuration) to further include a temperature protection circuit configured to switch the logic level of the output current detection signal depending on whether abnormal heat generation is occurring or not.

[0089] Furthermore, the switch device according to any one of the first to fourth configurations may be configured (fifth configuration) to further include a first signal input terminal configured to receive an external control signal for switching the switch element on / off, and a second signal input terminal configured to receive an external enable signal for switching between the first state and the second state.

[0090] Furthermore, for example, the electronic device disclosed in this specification is configured (sixth configuration) to include a switch device having any of the first to fifth configurations described above and a control device configured to receive input of the output current detection signal.

[0091] In addition, in the electronic device according to the sixth configuration, the control device may be configured (seventh configuration) to determine that the output terminal is in a short-to-power state when the output current detection signal is at a first logic level in both the first state and the second state during the off period of the switch element, and to determine that the output terminal is in an open-load state when the output current detection signal is at a second logic level in the first state and at the first logic level in the second state.

[0092] In the electronic device according to the seventh configuration, the control device may be configured (eighth configuration) to determine that the electronic device is in an output current detection state when the output current detection signal is lower than the overcurrent limit value during the on period of the switch element, and to determine that the electronic device is in a ground fault state or an overcurrent limit state when the output current detection signal is maintained at the overcurrent limit value.

[0093] Furthermore, in the electronic device according to the seventh configuration, the switch device may further include a temperature protection circuit configured to raise the output current detection signal above the overcurrent limit value when abnormal heat generation occurs, and the control device may be configured (ninth configuration) to determine that an abnormal heat generation state exists when the output current detection signal is raised above the overcurrent limit value during the on period of the switch element.

[0094] Furthermore, for example, the vehicle disclosed in this specification is configured (tenth configuration) to include an electronic device according to any one of the sixth to ninth configurations.

[0095] <Other Modifications> In addition, in the above embodiment, an in-vehicle high-side switch LSI is given as an example, but the application of the invention disclosed in this specification is not limited to this, and the invention can be widely applied to high-side switch LSIs other than those for in-vehicle use.

[0096] Furthermore, in addition to the above-described embodiments, various modifications can be made to the various technical features disclosed in this specification without departing from the spirit of the technical creation. In other words, the above-described embodiments should be considered to be illustrative and not restrictive in all respects. Furthermore, the technical scope of the present invention is defined by the claims, not by the description of the above-described embodiments, and should be understood to include all modifications that fall within the meaning and scope equivalent to the claims.

[0097] REFERENCE SIGNS LIST 1 Semiconductor integrated circuit device (switch device) 2 ECU (control device) 3 Load 4, 5 Resistor 10 NMOSFET (switch element) 20 NMOSFET (current detection element) 30 Gate control unit 31 Gate driver 32 Oscillator 33 Charge pump (booster unit) 34 Current detection circuit 35 Active clamp circuit 40 Control logic unit 51, 52 Signal input unit 60 Internal power supply unit 70 Abnormality protection unit 71 Overcurrent protection circuit 72 Output abnormality detection circuit 72A Current source 72B, 72C Resistor 72D Comparator 72E Enable control unit 72F Signal output unit 73 Temperature protection circuit 74 Undervoltage protection circuit 80 Soft start control unit T1 to T7 External terminal X Vehicle

Claims

1. a power supply terminal configured to receive a power supply voltage; an output terminal configured to have a load connected externally thereto; A switch element configured to be connected between the power supply terminal and the output terminal; a signal output terminal configured to output an output current detection signal corresponding to an output current flowing during an ON period of the switch element; an overcurrent protection circuit configured to limit the output current detection signal to a predetermined overcurrent limit value or less during the on-period of the switch element; an output abnormality detection circuit configured to switch between a first state in which no current is supplied to the output terminal during an off period of the switch element and a second state in which a current is supplied to the output terminal, while monitoring an output voltage of the output terminal in each state, and to switch a logic level of the output current detection signal; A switch device comprising:

2. The output abnormality detection circuit includes: a current source configured to generate a current provided to the output terminal; a comparator configured to compare a monitor voltage corresponding to the output voltage with a predetermined threshold voltage to generate an output abnormality detection signal; an enable control unit configured to enable the comparator during the off period of the switch element and then switch between enable / disable of the current source; a signal output unit configured to switch a logic level of the output current detection signal in response to the output abnormality detection signal; The switch device according to claim 1 ,

3. The switch device according to claim 2 , wherein the output abnormality detection circuit further includes a voltage divider configured to divide the output voltage to generate the monitor voltage.

4. The switch device according to claim 1 , further comprising a temperature protection circuit configured to switch a logic level of the output current detection signal depending on whether abnormal heat generation occurs.

5. a first signal input terminal configured to receive an external control signal for switching the switch element on / off; a second signal input terminal configured to receive an external enable signal for switching between the first state and the second state; The switch device of claim 1 further comprising:

6. A switch device according to any one of claims 1 to 5; a control device configured to receive the output current detection signal; An electronic device comprising:

7. 7. The electronic device according to claim 6, wherein the control device determines that the output terminal is in a short-to-power state when the output current detection signal is at a first logic level in both the first state and the second state during the off period of the switch element, and determines that the output terminal is in a load-open state when the output current detection signal is at a second logic level in the first state and at the first logic level in the second state.

8. 8. The electronic device according to claim 7, wherein the control device determines that the output current detection state is present when the output current detection signal is lower than the overcurrent limit value during the on-period of the switch element, and determines that the output current detection state is present when the output current detection signal is maintained at the overcurrent limit value.

9. The switch device further includes a temperature protection circuit configured to raise the output current detection signal above the overcurrent limit value when abnormal heat is generated, 9. The electronic device according to claim 8, wherein the control device determines that an abnormal heat generation state occurs when the output current detection signal is pulled up higher than the overcurrent limit value during the on-period of the switch element.

10. A vehicle comprising the electronic device according to claim 6.