Status output circuit and power supply device

Abstract

The present invention protects a state output circuit. A state output circuit is provided, which outputs a state signal representing the state of a power supply device, and includes: a state output terminal that outputs the state signal; a reference potential line to which a reference potential is applied; a first pull-up terminal to which a first pull-up potential higher than the reference potential is applied; a connection switching unit that is provided between the state output terminal and the reference potential line and switches whether to connect the state output terminal to the reference potential line according to the state of the power supply device; a first protection resistor that is provided between the connection switching unit and the state output terminal; and a pull-up unit that pulls up a first connection line between the first protection resistor and a connection resistor to the first pull-up potential.

Description

Technical Field

[0001] The present invention relates to a status output circuit and a power supply device. Background Art

[0002] Conventionally, the following structure has been known: in a power supply device that supplies power to a load, a status signal indicating a status such as overcurrent and overheat in the power supply device is output (for example, refer to Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-5125 Summary of the Invention

[0004] Technical Problem to be Solved by the Invention

[0005] In a power supply device, it is preferable to protect a status output terminal that outputs a status signal.

[0006] Technical Solution for Solving the Technical Problem

[0007] In order to solve the above problems, in a first aspect of the present invention, a status output circuit is provided that outputs a status signal indicating the status of a power supply device. The status output circuit may include a status output terminal that outputs a status signal. The status output circuit may include a reference potential line to which a reference potential is applied. The status output circuit may include a first pull-up terminal to which a first pull-up potential higher than the reference potential is applied. The status output circuit may include a connection switching unit that is provided between the status output terminal and the reference potential line and switches whether to connect the status output terminal to the reference potential line according to the status signal. The status output circuit may include a first protection resistor provided between the connection switching unit and the status output terminal. The status output circuit may include a pull-up unit that pulls up a first connection line between the first protection resistor and the connection switching unit to the first pull-up potential.

[0008] The resistance value of the first protection resistor may be 1 kΩ or more.

[0009] The status output circuit may include a first protection diode, an anode of which is connected to the reference potential line and a cathode of which is connected to the first connection line.

[0010] The pull-up unit may have a pull-up resistor provided between the first connection line and the first pull-up terminal.

[0011] The resistance value of the pull-up resistor may be 10 kΩ or more.

[0012] The pull-up resistor may be a depletion-type MOSFET in which a gate terminal and a source terminal are connected.

[0013] The status output circuit may include a control unit that controls the connection switching unit according to the status of the power supply device. The status output circuit may include a power terminal that supplies power to the control unit. The power terminal and the first pull-up terminal may be the same terminal. The power terminal and the first pull-up terminal may also be different terminals.

[0014] The status output circuit may include a second pull-up terminal to which a second pull-up potential is applied. The pull-up unit may pull up the first connection line to a potential corresponding to the first pull-up potential or the second pull-up potential.

[0015] The pull-up unit may pull up the first connection line to a potential corresponding to the first pull-up potential when the second pull-up terminal is in an open state. The pull-up unit may pull up the first connection line to a potential corresponding to the second pull-up potential when the second pull-up terminal is connected to an external power supply.

[0016] The pull-up unit may include a potential generating MOSFET that is disposed between the first pull-up terminal, the second pull-up terminal, and the first connection line and generates a potential corresponding to the first pull-up potential or the second pull-up potential. The pull-up unit may include a first connection portion that connects the first pull-up terminal to the gate terminal of the potential generating MOSFET. The pull-up unit may include a second connection portion that connects the second pull-up terminal to the gate terminal of the potential generating MOSFET. The second connection portion may include a second protection resistor disposed between the second pull-up terminal and the gate terminal of the potential generating MOSFET.

[0017] The resistance value of the second protection resistor may be 1 kΩ or more.

[0018] The first connection portion may include a clamping diode disposed between the first pull-up terminal and the reference potential line. The first connection portion may include a first series resistor disposed between the clamping diode and the first pull-up terminal. The first connection portion may include a second series resistor disposed between the first series resistor and the first pull-up terminal. A second connection line between the first series resistor and the second series resistor may be connected to the gate terminal of the potential generating MOSFET.

[0019] The pull-up unit may include a second protection diode having an anode connected to the source terminal of the potential generating MOSFET and a cathode connected to the gate terminal of the potential generating MOSFET.

[0020] In a second aspect of the present invention, a power supply device that supplies power to a load is provided. The power supply device may include a control unit that detects the status of the power supply device. The power supply device may include a status output circuit according to the first aspect that outputs a status signal indicating the status of the power supply device.

[0021] In addition, the above-described invention content does not enumerate all the necessary features of the present invention. In addition, sub-combinations of these feature groups can also form the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. is a diagram showing an example of a power supply device 100 according to an embodiment of the present invention.

[0023] Figure 2 FIG. is a diagram showing a structural example of a state output circuit 150 according to a first comparative example.

[0024] Figure 3 FIG. is a diagram showing a structural example of a state output circuit 150 according to a second comparative example.

[0025] Figure 4 FIG. is a diagram showing a structural example of a state output circuit 150 according to a third comparative example.

[0026] Figure 5 FIG. is a diagram showing a structural example of a state output circuit 150 according to an embodiment.

[0027] Figure 6 FIG. is a diagram showing another structural example of a state output circuit 150 according to an embodiment.

[0028] Figure 7 FIG. is a diagram showing another structural example of a state output circuit 150 according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, the present invention will be described by way of embodiments of the invention. However, the following embodiments do not limit the invention claimed. In addition, not all combinations of the features described in the embodiments are necessary for the technical solution to solve the technical problem of the invention.

[0030] Figure 1 FIG. is a diagram showing an example of a power supply device 100 according to an embodiment of the present invention. The power supply device 100 of this example is a semiconductor chip having an input terminal 101, an output terminal 102, a high potential terminal 103, a reference potential terminal 104, and a state output terminal 105.

[0031] The power supply device 100 operates according to an input signal IN input to the input terminal 101 and supplies power to a load 200 connected to the output terminal 102. The input signal IN of this example can be a signal representing a case where power is supplied to the load 200 and a case where power is not supplied to the load 200 in a binary logical value.

[0032] A prescribed high potential VCC is applied to the high potential terminal 103. The high potential terminal 103 in this example is connected to a power supply 110 that generates the high potential VCC. A reference potential terminal 104 is applied with a reference potential lower than the high potential VCC. The reference potential in this example is the ground potential GND.

[0033] The power supply device 100 outputs a status signal ST indicating the internal status of the power supply device 100 from the status output terminal 105. The status signal ST can be, for example, a signal indicating an abnormality such as an overcurrent being detected. The status output terminal 105 can be connected to a processing device 130 that processes the status signal ST. The processing device 130 can be provided within the same chip package as the power supply device 100. The processing device 130 can be a dedicated device for processing the status signal ST or a general-purpose device. Based on the status signal ST, the processing device 130 can control the power supply device 100, can control other power supply devices 100, or can control other devices. For example, when an abnormality is detected in any one of the power supply devices 100, the processing device 130 connected to multiple power supply devices 100 stops the power supply from the multiple power supply devices 100. In addition, when an abnormality is detected in any one of the power supply devices 100, the processing device 130 can cause other devices to generate an alarm or can cause other devices to stop.

[0034] The power supply device 100 can include a drive circuit 10 and an output section 12. The output section 12 is connected to a load 200 via an output terminal 102 and supplies power to the load 200. The output section 12 can be a switching element such as an IGBT or a power MOSFET. The output section 12 has a control terminal G (e.g., a gate terminal), a source terminal S, and a drain terminal D. In this example, the drain terminal D is connected to the high potential terminal 103, and the source terminal S is connected to the output terminal 102. The output section 12 switches whether to apply the high potential VCC to the load 200 based on the potential difference between the control signal input to the control terminal G and the source terminal S.

[0035] The drive circuit 10 inputs a control signal corresponding to the input signal IN input to the input terminal 101 to the control terminal G of the output section 12. The drive circuit 10 is input with a signal having a potential based on the reference potential GND. The drive circuit 10 functions as a level shift circuit that level-shifts a signal based on the reference potential GND into a control signal based on the output potential OUT of the output section 12. The output potential OUT can be the potential of the source terminal S of the output section 12.

[0036] The power supply device 100 of this example has a control unit 50. The control unit 50 inputs a control signal having a logical value pattern corresponding to the input signal IN to the drive circuit 10. The control signal output by the control unit 50 becomes a potential corresponding to the reference potential GND in the case of the L logical value, and becomes a potential corresponding to the high potential VCC in the case of the H logical value. The potential corresponding to the reference potential GND may refer to a potential substantially equal to the reference potential GND. The potential corresponding to the high potential VCC may refer to a potential substantially equal to the high potential VCC.

[0037] The control unit 50 of this example controls the drive circuit 10 based on the internal state of the power supply device 100. The internal state of the power supply device 100 may refer to a state represented by at least one parameter among the voltage value, current value, and resistance value of a specified node, and the temperature of a specified location. The power supply device 100 of this example includes at least one of a low voltage detection unit 72, a load open detection unit 56, an overcurrent detection unit 58, and an overheat detection unit 60 that respectively monitor the internal state of the power supply device 100.

[0038] The low voltage detection unit 72 detects the voltage value of the high potential VCC of the high potential terminal 103. When the voltage value of the high potential VCC is lower than a specified reference value, the low voltage detection unit 72 notifies the control unit 50 that it is in an abnormal state.

[0039] The load open detection unit 56 detects whether the load 200 is connected to the output terminal 102. The load open detection unit 56 can detect whether the output terminal 102 is in an open state based on the output resistance when a specified voltage or current is output from the output terminal 102. In a state where the load 200 is not connected to the output terminal 102, the load open detection unit 56 should prevent the output unit 12 from becoming conductive, and when it detects that the load 200 is not connected, it notifies the control unit 50 that it is in an abnormal state.

[0040] The overcurrent detection unit 58 detects the current output from the output unit 12. When the output current value exceeds a specified reference value, the overcurrent detection unit 58 notifies the control unit 50 that it is in an abnormal state.

[0041] The overheat detection unit 60 detects the temperature of one or more parts in the power supply device 100. When the temperature in any part exceeds a specified reference value, the overheat detection unit 60 notifies the control unit 50 that it is in an abnormal state.

[0042] When the control unit 50 is notified by any of the detection units that it means to be in an abnormal state, regardless of the logic value of IN of the input signal, the output unit 12 is controlled to the off state. By setting the output unit 12 to the off state according to the internal state of the power supply device 100, the power supply device 100 can be protected.

[0043] The power supply device 100 has a status output circuit 150. When the control unit 50 is notified by any of the detection units that it means to be in an abnormal state, the control unit 50 causes the status output circuit 150 to output a status signal ST with a specified logic value. The status output circuit 150 in this example may have a MOSFET connected between the status output terminal 105 and the reference potential terminal 104. The control unit 50 in this example outputs an internal signal ST0 for controlling the MOSFET according to the internal state of the power supply device 100.

[0044] The power supply device 100 may have at least one of a diode 66 and a diode 68. The anode of the diode 66 is connected to the reference potential terminal 104, and the cathode is connected to the high potential terminal 103. When a voltage equal to or higher than a specified value is input to the high potential terminal 103, the diode 66 connects the high potential terminal 103 to the reference potential terminal 104, thereby protecting the power supply device 100.

[0045] The anode of the diode 68 is connected to the reference potential terminal 104, and the cathode is connected to the input terminal 101. When a voltage equal to or higher than a specified value is input to the input terminal 101, the diode 68 connects the input terminal 101 to the reference potential terminal 104, thereby protecting the power supply device 100.

[0046] The power supply device 100 may include an internal power supply 70. The internal power supply 70 is connected to the high potential terminal 103. The internal power supply 70 may generate a power supply voltage to be supplied to each circuit of the power supply device 100 according to the high potential VCC. For example, the internal power supply 70 supplies a power supply voltage to each detection unit.

[0047] Figure 2 It is a diagram showing a structural example of the status output circuit 150 according to the first comparative example. In this example, outside the power supply device 100, a pull-up power supply 134 and a pull-up resistor 132 are provided. The pull-up power supply 134 is connected to the status output terminal 105 via the pull-up resistor 132. Thus, the potential of the status output terminal 105 is pulled up by the pull-up power supply 134. The potential of the pull-up power supply 134 in this example is lower than the high potential VCC.

[0048] The status output circuit 150 includes a status output terminal 105, a reference potential line 162, a high potential line 161, a connection switching section 152, an output resistor 154, and a protection diode 156. A reference potential GND is applied to the reference potential line 162. The reference potential line 162 can be connected to Figure 1 the reference potential terminal 104 shown. A high potential higher than the reference potential GND is applied to the high potential line 161. In this example, the high potential VCC is applied to the high potential line 161. The high potential line 161 can be connected to the high potential terminal 103.

[0049] The connection switching section 152 is provided between the status output terminal 105 and the reference potential line 162. The connection switching section 152 switches whether to connect the status output terminal 105 to the reference potential line 162 according to whether an abnormal state is detected in the control section 50. In this example, the connection switching section 152 is a MOSFET in which the source terminal S is connected to the reference potential line 162 and the drain terminal D is connected to the status output terminal 105 via the output resistor 154. The internal signal ST0 is input to the gate terminal G of the connection switching section 152.

[0050] In this example, the status signal ST output from the status output terminal 105 becomes a potential corresponding to the pull-up power supply 134. For example, if the connection switching section 152 is in the conduction state, the status signal ST output from the status output terminal 105 becomes a potential obtained by dividing the pull-up potential through the output resistor 154 and the pull-up resistor 132. In addition, if the connection switching section 152 is in the off state, the status signal ST becomes the pull-up potential. Thus, the internal state of the power supply device 100 can be notified to the external processing device 130.

[0051] The output resistor 154 is provided between the status output terminal 105 and the connection switching section 152. The output resistor 154 is, for example, a resistor formed of polysilicon, but is not limited thereto. The resistance value of the output resistor 154 is about 10 Ω to 100 Ω.

[0052] The anode of the protection diode 156 is connected to the status output terminal 105, and the cathode is connected to the high potential line 161. When a high potential such as a surge is applied to the status output terminal 105, the protection diode 156 connects the status output terminal 105 to the high potential terminal 103, thereby protecting the connection switching section 152 and the like.

[0053] In the state output circuit 150 of this example, if the high potential VCC is small enough compared to the potential of the pull-up power supply 134, such as 0V, a large current flows from the pull-up power supply 134 through the high-potential terminal 103. Therefore, the state output circuit 150 cannot be sufficiently protected. Additionally, the pull-up potential generated by the pull-up power supply 134 is preferably determined based on the nominal value of the input voltage of the processing device 130, etc. However, if the pull-up potential of the pull-up power supply 134 is increased, the current easily flows from the pull-up power supply 134 through the high-potential terminal 103. Therefore, the state output circuit 150 of this example sometimes has difficulty adjusting the pull-up potential according to the characteristics of the processing device 130.

[0054] Figure 3 FIG. is a structural example diagram of the state output circuit 150 according to the second comparative example. In this example, a pull-up power supply 134 and a pull-up resistor 132 are also provided outside the power supply device 100.

[0055] The state output circuit 150 has Figure 2 In the structure of the state output circuit 150 shown, a protection diode 158 is provided instead of the protection diode 156. The anode of the protection diode 158 is connected to the reference potential line 162, and the cathode is connected to the state output terminal 105. When a high potential such as a surge is applied to the state output terminal 105, the protection diode 158 connects the state output terminal 105 to the reference potential line 162, thereby protecting the connection switching unit 152, etc.

[0056] In the state output circuit 150 of this example, if the state output terminal 105 is at a negative potential, a relatively large current flows through the protection diode 156 from the reference potential line 162 through the state output terminal 105. Therefore, the power consumption increases. Thus, the state output circuit 150 cannot be sufficiently protected. In addition, if the pull-up potential of the pull-up power supply 134 is increased, the current easily flows from the pull-up power supply 134 through the reference potential line 162. Therefore, the state output circuit 150 of this example sometimes has difficulty adjusting the pull-up potential according to the characteristics of the processing device 130.

[0057] Figure 4 FIG. is a structural example diagram of the state output circuit 150 according to the third comparative example. In this example, a pull-up power supply 134 and a pull-up resistor 132 are also provided outside the power supply device 100.

[0058] The state output circuit 150 has the following structure: In Figure 3In the structure of the state output circuit 150 shown, the cathode of the protection diode 158 is connected to the drain terminal D of the connection switching unit 152. According to this example, an output resistor 154 is provided between the state output terminal 105 and the protection diode 158. Therefore, when the state output terminal 105 becomes a negative potential, the current flowing through the state output terminal 105 from the reference potential line 162 can be suppressed.

[0059] However, since the resistance value of the output resistor 154 is about 10 Ω to 100 Ω, the power suppression effect is small. If the resistance value of the output resistor 154 is increased, the power suppression effect can be improved. However, when the state signal ST is at the L logic value, the potential of the state output terminal 105 is determined by the voltage division ratio between the pull-up resistor 132 and the output resistor 154. Therefore, if the resistance value of the output resistor 154 is increased, this potential rises, and the potential difference between the H logic value and the L logic value becomes smaller.

[0060] Figure 5 It is a diagram showing a structural example of the state output circuit 150 according to the embodiment. The state output circuit 150 of this example includes a high potential line 161, a reference potential line 162, a state output terminal 105, a connection switching unit 152, a first pull-up terminal, a first protection resistor 160, a first connection line 163, a pull-up unit 170, and a first protection diode 159. The high potential line 161, the reference potential line 162, the state output terminal 105, the connection switching unit 152, and the first protection diode 159 are the same as Figure 4 the high potential line 161, the reference potential line 162, the state output terminal 105, the connection switching unit 152, and the protection diode 158 shown.

[0061] A first pull-up potential higher than the reference potential GND is applied to the first pull-up terminal. The first pull-up terminal of this example is the high potential terminal 103, and the first pull-up potential is the high potential VCC.

[0062] The first protection resistor 160 is provided between the connection switching unit 152 and the state output terminal 105. The resistance value of the first protection resistor 160 is larger than Figure 4 the resistance value of the output resistor 154 in. Thereby, the current flowing through the state output terminal 105 can be suppressed. The resistance value of the first protection resistor 160 can be 1 kΩ or more. The resistance value of the first protection resistor 160 can be 5 kΩ or more, can be 10 kΩ or more, or can be 20 kΩ or more.

[0063] The first protection resistor 160 is, for example, a resistor formed of polysilicon or the like. In other examples, the first protection resistor 160 can also be a depletion-type MOSFET in which the gate terminal and the source terminal are connected.

[0064] The first connection line 163 is a wiring that connects the first protection resistor 160 to the state switching unit 152. In this example, the first connection line 163 is connected to the drain terminal of the MOSFET that connects to the switching unit 152.

[0065] The pull-up unit 170 pulls up the first connection line 163 to the first pull-up potential (high potential VCC in this example). The pull-up unit 170 in this example has a pull-up resistor 172 provided between the first pull-up terminal (high potential terminal 103 in this example) and the first connection line 163. The pull-up resistor 172 can be a resistor with a resistance value higher than that of the first protection resistor 160. The resistance value of the pull-up resistor 172 can be 10 kΩ or more, 50 kΩ or more, or 100 kΩ or more.

[0066] The pull-up resistor 172 in this example is a depletion-type MOSFET in which the source terminal S is connected to the gate terminal G, the drain terminal D is connected to the high potential line 161, and the source terminal S is connected to the first connection line 163. In other examples, the pull-up resistor 172 can also be a resistor formed of polysilicon or the like.

[0067] By providing the pull-up unit 170 between the first connection line 163 and the first pull-up terminal, even if the resistance value of the first protection resistor 160 is increased, the potential rise of the state output terminal 105 when the state signal ST is at the L logic value can be suppressed. In addition, even when the high potential VCC is near 0 V, a large current will not be supplied to the state output terminal 105 from the outside. In addition, by using a pull-up resistor 172 with a large resistance value, the current flowing from the reference potential line 162 through the first protection diode 159 to the high potential line 161 can be suppressed when the high potential VCC is near 0 V.

[0068] The anode of the first protection diode 159 is connected to the reference potential line 162, and the cathode is connected to the first connection line 163. By providing the first protection diode 159, the potential of the state signal ST can be clamped, and the processing device 130 can be protected.

[0069] In this example, the high potential terminal 103 functions as a power supply terminal that supplies power to the control unit 50. That is, the power supply terminal of the control unit 50 and the first pull-up terminal are the same terminal. Thereby, the number of terminals of the power supply device 100 can be suppressed.

[0070] Figure 6 It is a diagram showing another structural example of the state output circuit 150 according to the embodiment. The state output circuit 150 in this example has a pull-up terminal 106. The state output circuit 150 in this example is Figure 5In the structure shown, a pull-up terminal 106 is used to replace the high-potential terminal 103. The pull-up terminal 106 in this example is an example of the first pull-up terminal. The structure other than the pull-up terminal 106 is the same as Figure 5 the example shown. The pull-up terminal 106 is a terminal different from the power supply terminal of the control unit 50, i.e., the high-potential terminal 103. The pull-up terminal 106 in this example is a terminal of the power supply device 100.

[0071] A power supply different from the power supply connected to the high-potential terminal 103 is connected to the pull-up terminal 106. That is, an arbitrary first pull-up potential Vp can be set independently of the high potential VCC. For example, the first pull-up potential Vp corresponding to the characteristics of the processing device 130 can be set. The first pull-up potential Vp can be higher than the high potential VCC. The first pull-up potential Vp in this example is a positive potential.

[0072] Figure 7 FIG. shows another structural example of the state output circuit 150 according to the embodiment. The state output circuit 150 in this example has a first pull-up terminal to which a first pull-up potential is applied, and a second pull-up terminal to which a second pull-up potential is applied. The pull-up unit 170 pulls up the first connection line 163 to a potential corresponding to the first pull-up potential or the second pull-up potential. In addition, the potential corresponding to the pull-up potential refers to a potential that changes following the change of the pull-up potential.

[0073] In this example, the first pull-up terminal is the high-potential terminal 103, and the first pull-up potential is the high potential VCC. That is, the first pull-up terminal and the power supply terminal of the control unit 50 are the same terminal. In addition, the second pull-up terminal is the pull-up terminal 106, and the second pull-up potential is the pull-up potential Vp.

[0074] In this example, when the pull-up terminal 106 is in an open state, i.e., when the pull-up terminal 106 is not connected to an external power supply, the pull-up unit 170 pulls up the first connection line 163 to a potential corresponding to the first pull-up potential VCC. When the pull-up terminal 106 is connected to an external power supply, the pull-up unit 170 pulls up the first connection line 163 to a potential corresponding to the second pull-up potential Vp. The pull-up unit 170 can pull up the first connection line 163 to a potential determined by the second pull-up potential Vp and the first pull-up potential VCC when the pull-up terminal 106 is connected to an external power supply.

[0075] The pull-up unit 170 in this example has a first connection portion 181, a second connection portion 182, a second connection line 185, a potential generation MOSFET 174, a second protection diode 176, and a pull-up resistor 172. The pull-up resistor 172 is connected to Figure 6It is the same as the pull-up resistor 172 shown. That is, the pull-up resistor 172 is arranged between the first connection line 163 and the high-potential line 161. In this example, the high-potential line 161 is connected to the high-potential terminal 103 via a potential generation MOSFET and the first connection portion 181, and is connected to the pull-up terminal 106 via a potential generation MOSFET and the second connection portion 182.

[0076] The potential generation MOSFET 174 is arranged between the high-potential terminal 103 and the pull-up terminal 106 and the first connection line 163. The potential generation MOSFET 174 generates a potential corresponding to the first pull-up potential VCC or the second pull-up potential Vp. The drain terminal D of the potential generation MOSFET 174 is connected to the high-potential terminal 103 via the first connection portion 181. The source terminal S of the potential generation MOSFET 174 is connected to the high-potential line 161. The gate terminal G of the potential generation MOSFET 174 is connected to the high-potential terminal 103 via the first connection portion 181 and is connected to the pull-up terminal 106 via the second connection portion 182.

[0077] The first connection portion 181 includes a first series resistor 184, a second series resistor 183, and a clamping diode 186. The clamping diode 186 is arranged between the high-potential terminal 103 and the reference potential line 162. In this example, the anode of the clamping diode 186 is connected to the reference potential line 162, and the cathode is connected to the first series resistor 184.

[0078] The first series resistor 184 is arranged between the clamping diode 186 and the high-potential terminal 103. The first series resistor 184 in this example is a depletion-type MOSFET with the gate terminal G and the source terminal S connected. The source terminal S of the first series resistor 184 is connected to the clamping diode 186, and the drain terminal D is connected to the second series resistor 183.

[0079] The second series resistor 183 is arranged between the first series resistor 184 and the high-potential terminal 103. The second series resistor 183 in this example is a depletion-type MOSFET with the gate terminal G and the source terminal S connected. The source terminal S of the second series resistor 183 is connected to the first series resistor 184, and the drain terminal D is connected to the high-potential terminal 103. In addition, the drain terminal D of the potential generation MOSFET 174 is connected to the wiring between the high-potential terminal 103 and the second series resistor 183.

[0080] The second connection line 185 has a wiring that connects the first series resistor 184 and the second series resistor 183. The second connection line 185 is connected to the gate terminal G of the potential generating MOSFET. The drain current that can flow through the first series resistor 184 can be larger than the drain current that can flow through the second series resistor 183. That is, the channel area of the first series resistor 184 is larger than the channel area of the second series resistor 183. The channel area refers to the area of the channel in each MOSFET that is perpendicular to the direction in which the drain current Id flows. In other examples, the first series resistor 184 and the second series resistor 183 can also be resistors formed of polysilicon or the like. The resistance value of the first series resistor 184 can be smaller than the resistance value of the second series resistor 183. Thus, in the case where an excessive voltage is applied as the second pull-up potential Vp, the current flows from the pull-up terminal 106 through the reference potential line 162, and the current flowing from the pull-up terminal 106 to the high potential terminal 103 can be suppressed.

[0081] The second connection portion 182 can have a second protection resistor 187 provided between the pull-up terminal 106 and the gate terminal G of the potential generating MOSFET 174. The resistance value of the second protection resistor 187 can be 1 kΩ or more, can be 5 kΩ or more, can be 10 kΩ or more, or can be 20 kΩ or more. The resistance value of the second protection resistor 187 can be the same as the resistance value of the first protection resistor 160.

[0082] The anode of the second protection diode 176 is connected to the source terminal S of the potential generating MOSFET 174, and the cathode is connected to the gate terminal G of the potential generating MOSFET 174. Through the second protection diode 176, an excessive voltage applied between the gate and source of the potential generating MOSFET 174 can be suppressed.

[0083] In the case where the pull-up terminal 106 is in an open state, the potential of the second connection line 185 becomes a potential corresponding to the clamping voltage in the clamping diode 186. In Figure 7 it, the clamping voltage is set to Vz, and the threshold voltage of the potential generating MOSFET 174 is set to Vth. The potential Vz is higher than the threshold voltage Vth of the potential generating MOSFET 174. If the potential generating MOSFET 174 becomes in a conducting state, the potential of the high potential line 161 becomes Vz - Vth. Therefore, the first connection line 163 can be pulled up to a potential corresponding to the first pull-up potential VCC. The threshold voltage of the potential generating MOSFET 174 in this example is about 1 V.

[0084] If the second pull-up potential Vp is applied to the pull-up terminal 106, the potential of the second connection line 185 becomes the potential obtained by subtracting the voltage drop Vr in the second protection resistor 187 from the second pull-up potential Vp. A current flows from the pull-up terminal 106 through the second protection resistor 187 and the second series resistor 183 to the high-potential terminal 103. For example, when the resistance in the second protection resistor 187 is 10 kΩ and the current is 15 μA, the voltage drop Vr in the second protection resistor 187 is 0.15 V. If the potential generation MOSFET 174 is in the conducting state, the potential of the high-potential line 161 becomes Vp - Vr - Vth. Therefore, the first connection line 163 can be pulled up to a potential corresponding to the second pull-up potential Vp.

[0085] With such a structure, when the external power supply is not connected to the pull-up terminal 106, the first connection line 163 can be pulled up according to the first pull-up potential VCC. In addition, when the external power supply is connected to the pull-up terminal 106, the first connection line 163 can be pulled up according to the second pull-up potential Vp. Therefore, state signals ST of various potentials can be generated, which can correspond to processing devices 130 with various characteristics.

[0086] As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. Those skilled in the art can understand that various changes or improvements can be made to the above embodiments. It is clear from the description of the scope of the claims that the embodiments to which such changes or improvements are applied are also included in the technical scope of the present invention.

[0087] Reference Numeral Explanation

[0088] 10... Driving circuit

[0089] 12... Output unit

[0090] 50... Control unit

[0091] 56... Load open-circuit detection unit

[0092] 58... Overcurrent detection unit

[0093] 60... Overheat detection unit

[0094] 66, 68... Diodes

[0095] 70... Internal power supply

[0096] 72... Low-voltage detection unit

[0097] 100... Power supply device

[0098] 101... Input terminal

[0099] 102 ··· Output terminal,

[0100] 103 ··· High potential terminal,

[0101] 104 ··· Reference potential terminal,

[0102] 105 ··· Status output terminal,

[0103] 106 ··· Pull-up terminal,

[0104] 110 ··· Power supply,

[0105] 130 ··· Processing device,

[0106] 132 ··· Pull-up resistor,

[0107] 134 ··· Pull-up power supply,

[0108] 150 ··· Status output circuit,

[0109] 152 ··· Connection switching section,

[0110] 154 ··· Output resistor,

[0111] 156 ··· Diode,

[0112] 158 ··· Diode,

[0113] 159 ··· First protection diode,

[0114] 160 ··· First protection resistor,

[0115] 161 ··· High potential line,

[0116] 162 ··· Reference potential line,

[0117] 163 ··· First connection line,

[0118] 170 ··· Pull-up section,

[0119] 172 ··· Pull-up resistor,

[0120] 174 ··· Potential generating MOSFET,

[0121] 176 ··· Second protection diode,

[0122] 181 ··· First connection portion,

[0123] 182 ··· Second connection portion,

[0124] 183 ··· Second series resistor,

[0125] 184 ··· The first series resistor,

[0126] 185 ··· The second connecting wire,

[0127] 186 ··· The clamping diode,

[0128] 187 ··· The second protection resistor,

[0129] 200 ··· The load.

Claims

1. A state output circuit, outputs a state signal indicating the state of a power supply device, and the state output circuit is characterized in that it includes: a state output terminal that outputs the state signal; a reference potential line to which a reference potential is applied; a first pull-up terminal to which a first pull-up potential higher than the reference potential is applied; a connection switching unit provided between the state output terminal and the reference potential line, and switches whether to connect the state output terminal to the reference potential line according to the state signal; a first protection resistor provided between the connection switching unit and the state output terminal; a pull-up unit that pulls up a first connection line between the first protection resistor and the connection switching unit to the first pull-up potential; a control unit that controls the connection switching unit according to the state of the power supply device; and a power supply terminal that supplies power to the control unit, wherein the power supply terminal and the first pull-up terminal are the same terminal, or the power supply terminal and the first pull-up terminal are different terminals, and the first pull-up potential is higher than the potential of the power supply terminal.

2. The state output circuit according to claim 1, characterized in that the resistance value of the first protection resistor is 1 kΩ or more.

3. The state output circuit according to claim 1, characterized in that it further includes a first protection diode, an anode of the first protection diode is connected to the reference potential line, and a cathode of the first protection diode is connected to the first connection line.

4. The state output circuit according to claim 2, characterized in that it further includes a first protection diode, an anode of the first protection diode is connected to the reference potential line, and a cathode of the first protection diode is connected to the first connection line.

5. The state output circuit according to any one of claims 1 to 4, characterized in that the pull-up unit has a pull-up resistor provided between the first connection line and the first pull-up terminal.

6. The state output circuit according to claim 5, characterized in that the resistance value of the pull-up resistor is 10 kΩ or more.

7. The state output circuit according to claim 5, characterized in that the pull-up resistor is a depletion-type MOSFET with its gate terminal and source terminal connected.

8. The state output circuit according to any one of claims 1 to 4, characterized in that it further includes a second pull-up terminal to which a second pull-up potential is applied, and the pull-up unit pulls up the first connection line to a potential corresponding to the first pull-up potential or the second pull-up potential.

9. The state output circuit according to claim 8, characterized in that when the second pull-up terminal is in an open state, the pull-up unit pulls up the first connection line to a potential corresponding to the first pull-up potential, and when the second pull-up terminal is connected to an external power supply, the pull-up unit pulls up the first connection line to a potential corresponding to the second pull-up potential.

10. The state output circuit according to claim 8, wherein, the pull-up part has: a potential generation MOSFET, which is arranged between the first pull-up terminal, the second pull-up terminal and the first connection line, and generates a potential corresponding to the first pull-up potential or the second pull-up potential; a first connection part, which connects the first pull-up terminal to the gate terminal of the potential generation MOSFET; and a second connection part, which connects the second pull-up terminal to the gate terminal of the potential generation MOSFET, the second connection part includes a second protection resistor, and the second protection resistor is arranged between the second pull-up terminal and the gate terminal of the potential generation MOSFET.

11. The state output circuit according to claim 9, wherein, the pull-up part has: a potential generation MOSFET, which is arranged between the first pull-up terminal, the second pull-up terminal and the first connection line, and generates a potential corresponding to the first pull-up potential or the second pull-up potential; a first connection part, which connects the first pull-up terminal to the gate terminal of the potential generation MOSFET; and a second connection part, which connects the second pull-up terminal to the gate terminal of the potential generation MOSFET, the second connection part includes a second protection resistor, and the second protection resistor is arranged between the second pull-up terminal and the gate terminal of the potential generation MOSFET.

12. The state output circuit according to claim 10, wherein, the resistance value of the second protection resistor is 1 kΩ or more.

13. The state output circuit according to claim 11, wherein, the resistance value of the second protection resistor is 1 kΩ or more.

14. The state output circuit according to any one of claims 10 to 13, wherein, the first connection part has: a clamping diode, which is arranged between the first pull-up terminal and the reference potential line; a first series resistor, which is arranged between the clamping diode and the first pull-up terminal; and a second series resistor, which is arranged between the first series resistor and the first pull-up terminal, a second connection line between the first series resistor and the second series resistor is connected to the gate terminal of the potential generation MOSFET.

15. The state output circuit according to any one of claims 10 to 13, wherein, the pull-up part further has a second protection diode, the anode of the second protection diode is connected to the source terminal of the potential generation MOSFET, and the cathode of the second protection diode is connected to the gate terminal of the potential generation MOSFET.

16. The state output circuit according to claim 14, wherein, The pull-up portion further has a second protection diode, an anode of the second protection diode is connected to a source terminal of the potential generating MOSFET, and a cathode of the second protection diode is connected to a gate terminal of the potential generating MOSFET.

17. A power supply device, The power supply device supplies power to a load, Characterized in that, Comprising: A control unit that detects the state of the power supply device; And The state output circuit according to any one of claims 1 to 16, which outputs a state signal indicating the state of the power supply device.

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