Circuit device

Abstract

To provide a circuit arrangement that can protect a transistor from overheating and accelerate charging to a load and discharging from the load.SOLUTION: A circuit arrangement 100 includes a control circuit 185 that controls a transistor current based on a detected temperature. The detected temperature is a temperature detected by a temperature sensor circuit 188 that detects the temperature of a transistor 189. The transistor 189 performs charging to a load 300 to which a power supply voltage VCC is supplied. The transistor current is a current flowing in the transistor 189 during the charging. When the detected temperature is higher than a first threshold, the control circuit 185 reduces the transistor current, and when the detected temperature is lower than a second threshold lower than the first threshold, increases the transistor current.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a circuit device and the like.

Background Art

[0002] Patent Document 1 discloses a power supply unit that suppresses problems caused by heat generation of a field effect transistor provided in an inrush current prevention circuit. The power supply unit includes a first power supply that supplies a first voltage to a load and an inrush current prevention circuit. The inrush current prevention circuit suppresses the inrush current by diverting the output current of the first power supply to a load side different from the load to which the first voltage is supplied. The inrush current prevention circuit includes a field effect transistor and a thermistor that measures the temperature of the field effect transistor, and when it is determined that the temperature of the field effect transistor is the warning temperature, the field effect transistor is put into a drive stop state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a problem of suppressing heat generation of a transistor that charges a load or a transistor that discharges from a load, and performing charging to the load or discharging from the load as quickly as possible by the current flowing through the transistor. In Patent Document 1 above, since the output current of the first power supply is diverted to a load side different from the load to which the first voltage is supplied, even if the field effect transistor conducts current, it is not possible to speed up the charging of the load supplied by the first power supply.

Means for Solving the Problems

[0005] One aspect of the present disclosure relates to a circuit device including a control circuit that controls a transistor current flowing through a transistor in charging based on a detected temperature detected by a temperature sensor circuit that detects the temperature of a transistor that charges a load to which a power supply voltage is supplied. When the detected temperature is higher than a first threshold value, the control circuit decreases the transistor current, and when the detected temperature is lower than a second threshold value that is lower than the first threshold value, the control circuit increases the transistor current.

[0006] Another aspect of the present disclosure relates to a circuit device including a control circuit that controls a transistor current flowing through a transistor in discharging based on a detected temperature detected by a temperature sensor circuit that detects the temperature of a transistor that discharges a load to which a power supply voltage is supplied. When the detected temperature is higher than a first threshold value, the control circuit decreases the transistor current, and when the detected temperature is lower than a second threshold value that is lower than the first threshold value, the control circuit increases the transistor current.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0008] Hereinafter, preferred embodiments of the present disclosure will be described in detail. Note that the embodiments described below do not unduly limit the content described in the claims, and not all of the configurations described in the embodiments are essential constituent elements.

[0009] 1. Circuit device and electronic device FIG. 1 is a configuration example of a circuit device 100 and an electronic device 10 in the present embodiment. The electronic device 10 includes an external transistor 11, a load 300, and a circuit device 100. Hereinafter, an example in which the external transistor 11 is an N-type transistor will be mainly described, but the present invention is not limited thereto, and the external transistor 11 may be a P-type transistor.

[0010] The electronic device 10 may be, for example, a printing device, a video projection device, a wearable device, an information processing device, a display device, a television receiver, or a portable information terminal, etc., but is not limited thereto, and may be various devices using a DC power supply voltage VCC.

[0011] The external transistor 11 is provided between the power supply node NVCC and the load 300. Specifically, the drain of the external transistor 11 is connected to the power supply node NVCC, and the source is connected to the node NLOAD of the load 300. The external transistor 11 is a so-called power transistor, and supplies the power supply voltage VCC to the load 300 when it is on, and cuts off the supply of the power supply voltage VCC to the load 300 when it is off.

[0012] The power supply voltage VCC is supplied to the power supply node NVCC from a DC power supply. The DC power supply is, for example, an AC-DC converter, a DC-DC converter, or a battery. Although not shown in FIG. 1, these DC power supplies may be included in the electronic device 10.

[0013] The load 300 is a circuit that operates with the power supply voltage VCC supplied to the node NLOAD via the external transistor 11. The node NLOAD is the power supply node of the load 300. The load 300 is, for example, a power supply stabilizing capacitor provided between the node NLOAD and the ground voltage GND, a processing device that executes processing in the electronic device 10, or a motor driver that drives a motor. Note that the load 300 is not limited to these, and may be a circuit for realizing various functions in the electronic device 10.

[0014] The circuit device 100 controls the supply of the power supply voltage VCC to the load 300 by outputting a gate control voltage DRV to the gate of the external transistor 11. The circuit device 100 includes a regulator 110, a charge pump circuit 120, a charging circuit 180, a discharging circuit 190, and terminals TCHP1, TCHP, TVCC, TDRV, TVCO, and TDIS. The circuit device 100 is, for example, an integrated circuit device in which a plurality of circuit elements are integrated on a semiconductor substrate. Each terminal is, for example, a pad of the integrated circuit device or a terminal of a package that houses the integrated circuit device.

[0015] The regulator 110 outputs a regulated voltage VRG by regulating the power supply voltage VCC from the power supply node NVCC. The terminal TVCC is connected to the power supply node NVCC, and the power supply voltage VCC is supplied to the regulator 110 via the terminal TVCC. The regulator 110 is a step-down regulator that outputs a regulated voltage VRG lower than the power supply voltage VCC. The regulator 110 is, for example, a linear regulator, but is not limited thereto and may be various types of DC-DC converters.

[0016] The charge pump circuit 120 performs boosting based on the regulated voltage VRG with reference to the source voltage VCO of the external transistor 11, and outputs a gate control voltage DRV = VCO + VRG that is higher than the source voltage VCO. As a result, when the charge pump circuit 120 is operating, the external transistor 11 is turned on, and the power supply voltage VCC is supplied to the load 300 via the external transistor 11.

[0017] Specifically, one end of the boost capacitor 12 is connected to the terminal TCHP1, the other end of the boost capacitor 12 is connected to the terminal TCHP2, and the gate of the external transistor 11 is connected to the terminal TDRV. The charge pump circuit 120 includes a drive circuit 160 and a gate control circuit 170. The drive circuit 160 outputs a drive signal CHP1 to one end of the boost capacitor 12 based on the regulated voltage VRG. A signal CHP2 from the other end of the boost capacitor 12 is input to the gate control circuit 170. The gate control circuit 170 outputs a gate control voltage DRV = VCO + VRG based on the signal CHP2 and the source voltage VCO of the external transistor 11. The gate control voltage DRV is output to the gate of the external transistor 11 via the terminal TDRV.

[0018] When the external transistor 11 is a P-type transistor, the source voltage of the external transistor 11 is the power supply voltage VCC. The charge pump circuit 120 may perform bucking based on the regulated voltage VRG with reference to the power supply voltage VCC, and output a gate control voltage DRV = VCC - VRG that is lower than the power supply voltage VCC.

[0019] The charging circuit 180 charges the capacitance of the node NLOAD of the load 300 before the external transistor 11 is turned on. As a result, the inrush current when the external transistor 11 is turned on is reduced. The capacitance of the node NLOAD of the load 300 is, for example, a power supply stabilization capacitor connected to the node NLOAD. The charging circuit 180 includes a transistor 189, a temperature sensor circuit 188, and a control circuit 185.

[0020] Transistor 189 is provided between the power supply node NVCC and the node NLOAD. Specifically, transistor 189 is a P-type transistor, with its source connected to terminal TVCC and its drain connected to terminal TVCO. Terminal TVCO is a terminal connected to the source of external transistor 11 and node NLOAD. Although FIG. 1 illustrates an example where transistor 189 is a P-type transistor, transistor 189 may be an N-type transistor.

[0021] The temperature sensor circuit 188 detects the temperature of transistor 189 and outputs a temperature detection voltage VTA whose voltage value changes according to the detected temperature. The temperature sensor circuit 188 is arranged in the vicinity of transistor 189 so as to be able to detect the temperature of transistor 189. The temperature sensor circuit 188 is, for example, a temperature sensor that utilizes the temperature dependence of the forward voltage of a PN junction, but is not limited thereto and may be various types of temperature sensors.

[0022] The control circuit 185 controls the transistor current by controlling the gate voltage GTA of transistor 189. The transistor current in the charging circuit 180 is the current flowing through transistor 189. The control circuit 185 controls the transistor current based on the temperature detection voltage VTA to prevent failures due to heat generation of transistor 189. In addition, the control circuit 185 performs control to allow the transistor current to flow as much as possible within the range where transistor 189 can be maintained below the allowable temperature. Details of this control will be described later.

[0023] The discharge circuit 190 discharges the capacitance of node NLOAD of the load 300 after the external transistor 11 is turned off. Thereby, after the external transistor 11 is turned off, problems caused by the voltage held in the capacitance of node NLOAD or the charge accumulated in the capacitance of node NLOAD can be prevented. The discharge circuit 190 includes transistor 199, temperature sensor circuit 198, and control circuit 195.

[0024] Transistor 199 is provided between node NLOAD and the ground node. Specifically, transistor 199 is an N-type transistor, with its source connected to the ground node and its drain connected to terminal TDIS. Terminal TDIS is the terminal connected to node NLOAD of load 300.

[0025] Temperature sensor circuit 198 detects the temperature of transistor 199 and outputs a temperature detection voltage VTB whose voltage value changes according to the detected temperature. Temperature sensor circuit 198 is arranged in the vicinity of transistor 199 so as to be able to detect the temperature of transistor 199. Temperature sensor circuit 198 is, for example, a temperature sensor that utilizes the temperature dependence of the forward voltage of a PN junction, but is not limited thereto and may be various types of temperature sensors.

[0026] Control circuit 195 controls the transistor current by controlling the gate voltage GTB of transistor 199. The transistor current in discharge circuit 190 is the current flowing through transistor 199. Control circuit 195 controls the transistor current based on temperature detection voltage VTB to prevent a failure due to heat generation of transistor 199. Further, control circuit 195 performs control to allow the transistor current to flow as much as possible within a range where transistor 199 can be maintained below the allowable temperature. Details of this control will be described later.

[0027] FIG. 2 is a state transition diagram of the control performed by control circuit 185 of charge circuit 180 and control circuit 195 of discharge circuit 190. Hereinafter, the control performed by control circuit 185 will be described as an example, but the control of control circuit 195 is the same. Also hereinafter, an example will be described in which the possible current values of transistor current Itr are three values: a first current value I1, a second current value I2, and a third current value I3, but the possible current values of transistor current Itr may be four or more.

[0028] The second current value I2 is smaller than the first current value I1, and the third current value I3 is smaller than the second current value I2. When the first current value I1 is 100%, for example, the second current value I2 is 50% of I1, and the third current value I3 is 0% of I1. However, the current values are not limited to this, and it is sufficient if I1 > I2 > I3 is satisfied.

[0029] When starting the charge control, the control circuit 185 transitions to the state SI1 and sets the transistor current Itr to I1. When the detected temperature TIC becomes equal to or higher than the first threshold TH in the state SI1, the control circuit 185 transitions to the state SI2A and sets the transistor current Itr to I2, which is smaller than I1. The first threshold TH is set to a temperature lower than the upper limit temperature at which the junction of the transistor 189 does not fail due to heat.

[0030] When the detected temperature TIC becomes lower than the second threshold TL before the elapse of the first period WAIT1 after transitioning to the state SI2A, the control circuit 185 transitions to the state SI1. The second threshold TL is a temperature lower than the first threshold TH. The second threshold TL is set to a temperature at which the transistor current Itr can be maintained to some extent, for example, a temperature several degrees to several tens of degrees lower than the first threshold TH. In the state SI2A, the control circuit 185 does not determine whether the detected temperature TIC is equal to or higher than the first threshold TH. When the first period WAIT1 elapses after transitioning to the state SI2A, the control circuit 185 transitions to the state SI2B and determines whether the detected temperature TIC is equal to or higher than the first threshold TH and whether the detected temperature TIC is lower than the second threshold TL.

[0031] When the detected temperature TIC becomes lower than the second threshold TL in the state SI2B, the control circuit 185 transitions to the state SI1. Also, when the detected temperature TIC becomes equal to or higher than the first threshold TH in the state SI2B, the control circuit 185 transitions to the state SI3 and sets the transistor current Itr to I3, which is lower than I2.

[0032] When transitioning from state SI1 to state SI2A, since the transistor current Itr decreases to I2, the heat generation amount of transistor 189 decreases. At this time, the temperature of transistor 189 may or may not start to decrease. When transitioning from state SI1 to state SI2A, it is considered that the temperature of transistor 189 temporarily exceeds the first threshold TH. Therefore, when the temperature starts to decrease, a first period WAIT1 is provided as a waiting time for waiting for the detected temperature TIC to fall below the first threshold TH. On the other hand, if the temperature of transistor 189 does not decrease after transitioning to state SI2A, after the first period WAIT1 has elapsed, it transitions from state SI2B to state SI3, and the transistor current Itr decreases to I3.

[0033] When the detected temperature TIC becomes lower than the second threshold TL in state SI3, the control circuit 185 transitions to state SI2C and sets the transistor current Itr to I2, which is larger than I3.

[0034] When the detected temperature TIC becomes equal to or higher than the first threshold TH before the second period WAIT2 has elapsed after transitioning to state SI2C, the control circuit 185 transitions to state SI3. In state SI2C, the control circuit 185 does not determine whether the detected temperature TIC is lower than the second threshold TL. When the second period WAIT2 has elapsed after transitioning to state SI2C, the control circuit 185 transitions to state SI2D and determines whether the detected temperature TIC is equal to or higher than the first threshold TH and whether the detected temperature TIC is lower than the second threshold TL.

[0035] When the detected temperature TIC becomes equal to or higher than the first threshold TH in state SI2D, the control circuit 185 transitions to state SI3. Also, when the detected temperature TIC becomes lower than the second threshold TL in state SI2D, the control circuit 185 transitions to state SI1 and sets the transistor current Itr to I1, which is larger than I2.

[0036] When transitioning from state SI3 to state SI2C, the transistor current Itr rises to I2, so the heat generation amount of transistor 189 increases. At this time, the temperature of transistor 189 may or may not start to rise. When transitioning from state SI3 to state SI2C, it is considered that the temperature of transistor 189 temporarily falls below the second threshold value TL. Therefore, when the temperature starts to rise, a second period WAIT2 is provided as a wait time for waiting for the detected temperature TIC to exceed the second threshold value TL. On the other hand, if the temperature of transistor 189 does not rise after transitioning to state SI2C, after the second period WAIT2 has elapsed, it transitions from state SI2D to state SI1, and the transistor current Itr rises to I1.

[0037] The second period WAIT2 is longer than the first period WAIT1. Since the heat of transistor 189 diffuses into the surroundings, it is assumed that the rate at which the temperature of transistor 189 rises is slower than the rate at which the temperature of transistor 189 falls. For this reason, the second period WAIT2 for waiting for the detected temperature TIC to exceed the second threshold value TL is set longer than the first period WAIT1 for waiting for the detected temperature TIC to fall below the first threshold value TH.

[0038] Figure 3 is a first waveform diagram for explaining the operation of the charging circuit 180. Here, an example of reciprocating between states SI1 and SI2A is shown. Hereinafter, the operation of the charging circuit 180 will be described as an example, but the operation of the discharging circuit 190 is the same. However, in charging, the voltage of the node NLOAD of the load 300 gradually rises with charging, while in discharging, the voltage of the node NLOAD of the load 300 gradually decreases with discharging.

[0039] When the charging control starts, the control circuit 185 transitions to state SI1, the transistor 189 conducts a transistor current Itr = I1, the transistor 189 generates heat and the detected temperature TIC rises. When the detected temperature TIC reaches the first threshold value TH, the control circuit 185 transitions to state SI2A and the transistor current Itr drops to I2. The heat generation amount of the transistor 189 decreases and the detected temperature TIC drops. When the detected temperature TIC falls below the second threshold value TL, the control circuit 185 transitions to state SI1 and the transistor current Itr rises to I1. Thereafter, states SI1 and SI2A are repeated until the node NLOAD of the load 300 rises near the power supply voltage VCC, so that the temperature of the transistor 189 is maintained between the first threshold value TH and the second threshold value TL. As a result, since the temperature of the transistor 189 does not exceed the first threshold value TH which is the allowable temperature, the transistor 189 can be protected from overheating. Also, since the transistor current is controlled so that the temperature of the transistor 189 does not fall below the second threshold value TL, the transistor 189 can charge the capacitance of the node NLOAD of the load 300 with the largest possible transistor current.

[0040] When the node NLOAD approaches the power supply voltage VCC, the voltage between the source and drain of the transistor 189 decreases and the heat generation amount of the transistor 189 decreases, so state SI1 is maintained. When the capacitance of the node NLOAD is charged up to the power supply voltage VCC, no current flows through the transistor 189. Thereafter, the control circuit 185 turns off the transistor 189 and the charge pump circuit 120 operates to turn on the external transistor 11.

[0041] FIG. 4 is a second waveform diagram for explaining the operation of the charging circuit 180. Hereinafter, the operation of the charging circuit 180 will be described as an example, but the operation of the discharging circuit 190 is the same. However, in charging, the voltage of the node NLOAD of the load 300 gradually rises with charging, while in discharging, the voltage of the node NLOAD of the load 300 gradually decreases with discharging.

[0042] When the charging control is started, the voltage of the node NLOAD of the load 300, that is, the source voltage VCO of the external transistor 11, is 0V. Therefore, the voltage between the source and drain of the transistor 189 is the power supply voltage VCC, and when the transistor current Itr = I1 flows in the state SI1, the amount of heat generation is large, and the temperature of the transistor 189 rises in a short time and the state transitions to SI2A, and the transistor current Itr becomes I2. Immediately after the start of charging, since the temperature around the transistor 189 has not risen, the heat of the transistor 189 is easily diffused to the surroundings, so the temperature of the transistor 189 drops and the state transitions to SI1, and the transistor current Itr becomes I1.

[0043] As this is repeated, the temperature around the transistor 189 rises, so the heat of the transistor 189 is less likely to diffuse to the surroundings, and the temperature of the transistor 189 is less likely to drop. Then, the state comes to stay in SI2A, and after the first period WAIT1 has elapsed in the state SI2A, the state transitions to SI2B. When it is determined that the detected temperature TIC is equal to or higher than the first threshold value TH in the state SI2B, the state transitions to SI3, and the transistor current Itr becomes I3. Since the transistor current Itr has decreased, the temperature of the transistor 189 drops and the state transitions to SI2C, and the transistor current Itr becomes I2. Thereafter, the state reciprocates between SI3 and SI2C.

[0044] Since the capacitance of the node NLOD of the load 300 is charged by the transistor current Itr, the source voltage VCO of the external transistor 11 increases. Then, since the voltage between the source and drain of the external transistor 11 decreases, the heat generation amount of the transistor 189 decreases, and the time for the state to stay in SI2C becomes longer. After the second period WAIT2 has elapsed in the state SI2C, the state transitions to SI2D. When it is determined that the detected temperature TIC is lower than the second threshold value TL in the state SI2D, the state transitions to SI1, and the transistor current Itr becomes I1. Since the transistor current Itr has increased, the temperature of the transistor 189 rises and the state transitions to SI2A, and the transistor current Itr becomes I2.

[0045] As this is repeated, the source voltage VCO further increases, so the voltage between the source and drain of the external transistor 11 decreases, and the heat generation amount of the transistor 189 decreases. Then, the state comes to stay in SI1, and when the capacitance of the node NLOD of the load 300 is charged up to the power supply voltage VCC, no current flows through the transistor 189. Thereafter, the transistor 189 turns off and the external transistor 11 turns on.

[0046] In the above-described embodiment, the circuit device 100 includes a control circuit 185 that controls the transistor current based on the detected temperature. The detected temperature is the temperature detected by the temperature sensor circuit 188 that detects the temperature of the transistor 189. The transistor 189 charges the load 300 to which the power supply voltage VCC is supplied. The transistor current is the current that flows through the transistor 189 during charging. The control circuit 185 decreases the transistor current when the detected temperature is higher than the first threshold value TH, and increases the transistor current when the detected temperature is lower than the second threshold value TL that is lower than the first threshold value TH.

[0047] According to this embodiment, when the detected temperature becomes higher than the first threshold value TH, the transistor current decreases, so the temperature of the transistor 189 drops. As a result, the transistor 189 can be protected from overheating. Also, when the detected temperature becomes lower than the second threshold value TL, the transistor current increases, so the transistor current is controlled so that the detected temperature is in the range from the second threshold value TL to the first threshold value TH. Thereby, within a range not exceeding the first threshold value TH which is the allowable temperature, the transistor 189 can charge the capacitance of the node NLOAD of the load 300 with a transistor current as large as possible.

[0048] In addition, in FIG. 1, an example in which the transistor 189 and the temperature sensor circuit 188 are provided inside the circuit device 100 has been described, but the present invention is not limited to this, and the transistor 189 and the temperature sensor circuit 188 may be provided outside the circuit device 100.

[0049] In the above-described embodiment, the circuit device 100 includes a control circuit 195 that controls the transistor current based on the detected temperature. The detected temperature is the temperature detected by the temperature sensor circuit 198 that detects the temperature of the transistor 199. The transistor 199 discharges from the load 300 to which the power supply voltage VCC is supplied. The transistor current is the current flowing through the transistor 199 in the discharge. When the detected temperature is higher than the first threshold value TH, the control circuit 195 decreases the transistor current, and when the detected temperature is lower than the second threshold value TL which is lower than the first threshold value TH, the control circuit 195 increases the transistor current.

[0050] According to this embodiment, when the detected temperature becomes higher than the first threshold value TH, the transistor current decreases, so the temperature of the transistor 199 drops. As a result, the transistor 199 can be protected from overheating. Also, when the detected temperature becomes lower than the second threshold value TL, the transistor current increases, so the transistor current is controlled so that the detected temperature is in the range from the second threshold value TL to the first threshold value TH. Thereby, within a range not exceeding the first threshold value TH which is the allowable temperature, the transistor 199 can discharge from the capacitance of the node NLOAD of the load 300 with a transistor current as large as possible.

[0051] In FIG. 1, an example in which the transistor 199 and the temperature sensor circuit 198 are provided inside the circuit device 100 has been described. However, the present invention is not limited to this, and the transistor 199 and the temperature sensor circuit 198 may be provided outside the circuit device 100.

[0052] In FIG. 1, an example in which the circuit device 100 includes both the charging circuit 180 and the discharging circuit 190 has been described. However, the circuit device 100 may include only either the charging circuit 180 or the discharging circuit 190.

[0053] Hereinafter, the control circuit 185 will be described as an example, but the same applies to the control circuit 195.

[0054] In the present embodiment, the control circuit 185 performs control to set the transistor current to the first current value I1, the second current value I2 smaller than the first current value I1, or the third current value I3 smaller than the second current value I2. When the transistor current is the second current value I2 and the detected temperature is higher than the first threshold value TH, the control circuit 185 performs control to set the transistor current to the third current value I3. In the example of FIG. 3, this control corresponds to the transition from SI2B to SI3 or the transition from SI2C to SI3. When the transistor current is the second current value I2 and the detected temperature is lower than the second threshold value TL, the control circuit 185 performs control to set the transistor current to the first current value I1. In the example of FIG. 3, this control corresponds to the transition from SI2A to SI1 or the transition from SI2D to SI1.

[0055] According to the present embodiment, when the detected temperature is higher than the first threshold value TH, the control circuit 185 can decrease the transistor current by changing the transistor current from the second current value I2 to the third current value I3. Further, when the detected temperature is higher than the second threshold value TL, the control circuit 185 can increase the transistor current by changing the transistor current from the second current value I2 to the first current value I1.

[0056] Also, in this embodiment, when the transistor current is the first current value I1 and the detected temperature is higher than the first threshold value TH, the control circuit 185 performs control to set the transistor current to the second current value I2. In the example of FIG. 3, this control corresponds to the transition from SI1 to SI2A. After the first period WAIT1 has elapsed since the control circuit 185 sets the transistor current to the second current value I2, it determines whether the detected temperature is higher than the first threshold value TH. When it determines that the detected temperature is higher than the first threshold value TH, it sets the transistor current to the third current value I3. In the example of FIG. 3, this control corresponds to the transition from SI2A to SI2B and the transition from SI2B to SI3.

[0057] When the transistor current is the first current value I1, if the detected temperature exceeds the first threshold value TH, the transistor current becomes the second current value I2. At this time, it is considered that the detected temperature temporarily exceeds the first threshold value TH. If the first period WAIT1 is not provided, since the detected temperature exceeds the first threshold value TH, the transistor current is changed from the second current value I2 to the third current value I3. That is, although the temperature may decrease due to the decrease in the transistor current to the second current value I2, the transistor current further decreases to the third current value I3. In this regard, according to this embodiment, when the temperature turns to decrease after the transistor current decreases to the second current value I2, since the first period WAIT1 for waiting until the temperature falls below the first threshold value TH is provided, the transistor current does not decrease to the third current value I3. Thereby, the transistor current can be transitioned between two states, that is, between the first current value I1 and the second current value I2.

[0058] Also, in the present embodiment, when the transistor current is the third current value I3 and the detected temperature is lower than the second threshold value TL, the control circuit 185 performs control to set the transistor current to the second current value I2. In the example of FIG. 3, this control corresponds to the transition from SI3 to SI2C. After the second period WAIT2 has elapsed since the control circuit 185 sets the transistor current to the second current value I2, the control circuit 185 determines whether the detected temperature is lower than the second threshold value TL. When it is determined that the detected temperature is lower than the second threshold value TL, the control circuit 185 performs control to set the transistor current to the first current value I1. In the example of FIG. 3, this control corresponds to the transition from SI2C to SI2D and the transition from SI2D to SI1.

[0059] When the transistor current is the third current value I3, if the detected temperature is lower than the second threshold value TL, the transistor current becomes the second current value I2. At this time, it is considered that the detected temperature temporarily drops below the second threshold value TL. If the second period WAIT2 is not provided, since the detected temperature is lower than the second threshold value TL, the transistor current is changed from the second current value I2 to the first current value I1. That is, although the temperature may rise due to the increase in the transistor current to the second current value I2, the transistor current further increases to the first current value I1. In this regard, according to the present embodiment, when the temperature rises after the transistor current increases to the second current value I2, since the second period WAIT2 for waiting until the temperature exceeds the second threshold value TL is provided, the transistor current does not increase to the first current value I1. Thereby, the transistor current can be switched between two states, that is, between the third current value I3 and the second current value I2.

[0060] Also, in the present embodiment, the length of the second period WAIT2 is longer than the length of the first period WAIT1.

[0061] Since the heat of the transistor 189 diffuses to the surroundings, it is assumed that the rate at which the temperature of the transistor 189 rises is slower than the rate at which the temperature of the transistor 189 falls. For this reason, by setting the second period WAIT2 for waiting for the detected temperature to exceed the second threshold value TL to be longer than the first period WAIT1 for waiting for the detected temperature to fall below the first threshold value TH, appropriate wait control is realized.

[0062] Also, in the present embodiment, the transistor 189 is connected in parallel to an external transistor 11 provided between the node NVCC of the power supply voltage VCC and the node NLOAD of the load 300. The transistor 189 charges the load 300 before the external transistor 11 turns on.

[0063] Since the transistor 189 is connected in parallel to the external transistor 11, the capacitance of the node NLOAD of the load 300 can be charged by the transistor current of the transistor 189 before the external transistor 11 turns on. According to the present embodiment, it is possible to achieve both protecting the transistor 189 from overheating and charging as fast as possible within the range where it can be protected.

[0064] Also, in the present embodiment, the transistor 199 is provided between the node NLOAD of the load 300 and the ground node. The transistor 199 discharges the load 300 after the external transistor 11 turns off.

[0065] Since the transistor 199 is provided between the node NLOAD of the load 300 and the ground node, after the external transistor 11 turns off, the capacitance of the node NLOAD of the load 300 can be discharged by the transistor current of the transistor 199. According to the present embodiment, it is possible to achieve both protecting the transistor 199 from overheating and discharging as fast as possible within the range where it can be protected.

[0066] 2. Detailed configuration example FIG. 5 shows a detailed configuration example of the charging circuit 180. The charging circuit 180 includes a transistor 189, a temperature sensor circuit 188, a control circuit 185, and a reference voltage generation circuit 140.

[0067] The reference voltage generation circuit 140 generates a first reference voltage VH, a second reference voltage VL, and a third reference voltage VTSD. The first reference voltage VH is a voltage corresponding to the first threshold TH and has the same voltage value as the temperature detection voltage VTA when the detected temperature TIC is the first threshold TH. The second reference voltage VL is a voltage corresponding to the second threshold TL and has the same voltage value as the temperature detection voltage VTA when the detected temperature TIC is the second threshold TL. The third reference voltage VTSD is a voltage corresponding to the third threshold Tmax and has the same voltage value as the temperature detection voltage VTA when the detected temperature TIC is the third threshold Tmax. As shown in FIG. 3, the third threshold Tmax is a temperature higher than the first threshold TH and corresponds to the allowable upper limit temperature of the circuit device 100.

[0068] The control circuit 185 includes a high-temperature side temperature detection circuit 181, a low-temperature side temperature detection circuit 182, a protection temperature detection circuit 183, a state control circuit 186, and a constant current control circuit 187.

[0069] The high-temperature side temperature detection circuit 181 detects whether the temperature detection voltage VTA is higher than the first reference voltage VH and outputs the detection signal THDA.

[0070] The low-temperature side temperature detection circuit 182 detects whether the temperature detection voltage VTA is lower than the second reference voltage VL and outputs the detection signal TLDA.

[0071] The protection temperature detection circuit 183 detects whether the temperature detection voltage VTA is higher than the third reference voltage VTSD, and after the temperature detection voltage VTA exceeds the third reference voltage VTSD, detects whether the temperature detection voltage VTA becomes lower than the fourth reference voltage Vmin, and outputs the detection signal TSDDA. The fourth reference voltage Vmin is a voltage corresponding to the fourth threshold Tmin. As shown in FIG. 3, the fourth threshold Tmin is a voltage lower than the second threshold TL.

[0072] The state control circuit 186 performs the control described with reference to FIG. 2 based on the detection signals THDA and TLDA. At this time, the state control circuit 186 outputs a current setting signal CNTA for setting the current value of the transistor current to the constant current control circuit 187. The constant current control circuit 187 controls the transistor current to the current value indicated by the current setting signal CNTA by outputting a gate voltage GTA corresponding to the current value indicated by the current setting signal CNTA to the gate of the transistor 189. Further, the state control circuit 186 includes a timer TMA, and uses the timer TMA to perform wait control for the first period WAIT1 in the state SI2A and wait control for the second period WAIT2 in the state SI2C.

[0073] Further, when a detection signal TSDDA indicating that the temperature of the transistor 189 has exceeded the third threshold value Tmax is input, the state control circuit 186 stops the control of FIG. 2 and outputs a current setting signal CNTA for turning off the transistor 189. Thereafter, when a detection signal TSDDA indicating that the temperature of the transistor 189 has fallen below the fourth threshold value Tmin is input, the state control circuit 186 resumes the control of FIG. 2.

[0074] When the protection temperature detection circuit 183 outputs a detection signal TSDDA indicating that the temperature of the transistor 189 has exceeded the third threshold value Tmax, the circuit device 100 enters a shutdown state. Thereafter, when the protection temperature detection circuit 183 outputs a detection signal TSDDA indicating that the temperature of the transistor 189 has fallen below the fourth threshold value Tmin, the circuit device 100 releases the shutdown state.

[0075] FIG. 6 is a detailed configuration example of the discharge circuit 190. The discharge circuit 190 includes a transistor 199, a temperature sensor circuit 198, and a control circuit 195. FIG. 6 shows an example in which a reference voltage generation circuit 140 common to the charge circuit 180 and the discharge circuit 190 is provided. However, a reference voltage generation circuit may be provided separately for the charge circuit 180 and the discharge circuit 190.

[0076] The control circuit 195 includes a high-temperature-side temperature detection circuit 191, a low-temperature-side temperature detection circuit 192, a protection temperature detection circuit 193, a state control circuit 196, and a constant-current control circuit 197.

[0077] The high-temperature-side temperature detection circuit 191 detects whether the temperature detection voltage VTB is higher than the first reference voltage VH, and outputs the detection signal THDB.

[0078] The low-temperature-side temperature detection circuit 192 detects whether the temperature detection voltage VTB is lower than the second reference voltage VL, and outputs the detection signal TLDB.

[0079] The protection temperature detection circuit 193 detects whether the temperature detection voltage VTB is higher than the third reference voltage VTSD, and after the temperature detection voltage VTB exceeds the third reference voltage VTSD, detects whether the temperature detection voltage VTB becomes lower than the fourth reference voltage Vmin, and outputs the detection signal TSDDB.

[0080] Based on the detection signals THDB and TLDB, the state control circuit 196 performs the same control as shown in FIG. 2. At this time, the state control circuit 196 outputs a current setting signal CNTB for setting the current value of the transistor current to the constant-current control circuit 197. The constant-current control circuit 197 controls the transistor current to the current value indicated by the current setting signal CNTB by outputting a gate voltage GTB corresponding to the current value indicated by the current setting signal CNTB to the gate of the transistor 199. Further, the state control circuit 196 includes a timer TMB, and uses the timer TMB to perform the wait control for the first period WAIT1 in the state SI2A and the wait control for the second period WAIT2 in the state SI2C.

[0081] Also, when a detection signal TSDDB indicating that the temperature of transistor 199 has exceeded the third threshold value Tmax is input, the state control circuit 196 stops the control of FIG. 2 and outputs a current setting signal CNTB for turning off transistor 199. Thereafter, when a detection signal TSDDB indicating that the temperature of transistor 199 has fallen below the fourth threshold value Tmin is input, the state control circuit 196 resumes the control of FIG. 2.

[0082] When the protection temperature detection circuit 193 outputs a detection signal TSDDB indicating that the temperature of transistor 199 has exceeded the third threshold value Tmax, the circuit device 100 enters a shutdown state. Thereafter, when the protection temperature detection circuit 193 outputs a detection signal TSDDB indicating that the temperature of transistor 199 has fallen below the fourth threshold value Tmin, the circuit device 100 releases the shutdown state.

[0083] FIG. 7 shows a detailed configuration example of the constant current control circuit 187. Note that the constant current control circuit 197 has a similar configuration. The constant current control circuit 187 includes a current source IBG and transistors TRG1 to TRG6.

[0084] Transistors TRG6, TRG3, and TRG4 are N-type transistors and constitute a current mirror circuit. The current output from the current source IBG flows through transistor TRG6, and this current is mirrored to the currents flowing through transistors TRG3 and TRG4. Let this mirrored current be I0.

[0085] Transistors TRG1 and TRG2 are N-type transistors. Transistor TRG1 is provided in series with transistor TRG3, and when transistor TRG1 is on, current I0 flows through transistor TRG3. Transistor TRG2 is provided in series with transistor TRG4, and when transistor TRG2 is on, current I0 flows through transistor TRG4. A signal CNT1 is input from control circuit 185 to the gate of transistor TRG1. Transistor TRG1 is off when CNT1 = 0 and on when CNT1 = 1. A signal CNT2 is input from control circuit 185 to the gate of transistor TRG2. Transistor TRG2 is off when CNT2 = 0 and on when CNT2 = 1. Signals CNT1 and CNT2 correspond to the current setting signal CNTA in FIG. 5.

[0086] Transistor TRG5 is a P-type transistor. The current flowing through transistors TRG3 and TRG4 flows through transistor TRG5, and this current is mirrored to the transistor current Itr flowing through transistor 189. The transistor current is Itr = I0×(CNT1 + CNT2), and can take three states: Itr = 0, I0, and 2×I0. In this example, I1, I2, and I3 in FIG. 2 are 0, I0, and 2×I0.

[0087] FIG. 8 is a detailed configuration example of temperature sensor circuit 188, reference voltage generation circuit 140, high-temperature side temperature detection circuit 181, low-temperature side temperature detection circuit 182, and protection temperature detection circuit 183. Note that high-temperature side temperature detection circuit 191, low-temperature side temperature detection circuit 192, and protection temperature detection circuit 193 also have a similar configuration.

[0088] Temperature sensor circuit 188 includes current source IBF and diodes DF1 and DF2. The current output by current source IBF flows through the series-connected diodes DF1 and DF2, thereby generating a voltage that is twice the forward voltage of the diode at the anode of diode DF1. This voltage is the temperature detection voltage VTA.

[0089] The reference voltage generation circuit 140 includes a first ladder resistor circuit formed by resistors RF3 to RF5 and a second ladder resistor circuit formed by resistors RF1 and RF2. The first ladder resistor circuit generates a first reference voltage VH and a second reference voltage VL by dividing the reference voltage VREF. The second ladder resistor circuit generates a third reference voltage VTSD by dividing the reference voltage VREF.

[0090] The high-temperature side temperature detection circuit 181 is a comparator that compares the temperature detection voltage VTA with the first reference voltage VH. This comparator outputs a low-level detection signal THDA when VTA > VH, and outputs a high-level detection signal THDA when VTA < VH.

[0091] The low-temperature side temperature detection circuit 182 is a comparator that compares the temperature detection voltage VTA with the second reference voltage VL. This comparator outputs a low-level detection signal TLDA when VTA > VL, and outputs a high-level detection signal TLDA when VTA < VL.

[0092] The protection temperature detection circuit 183 is a hysteresis comparator that compares the temperature detection voltage VTA with the third reference voltage VTSD. When VTA > VTSD while the detection signal TSDDA is at a high level, this hysteresis comparator changes the detection signal TSDDA from a high level to a low level. Also, when VTA < VTSD while the detection signal TSDDA is at a low level, this hysteresis comparator changes the detection signal TSDDA from a low level to a high level.

[0093] FIG. 9 is a detailed configuration example of the drive circuit 160 and the gate control circuit 170 that constitute the charge pump circuit 120.

[0094] The drive circuit 160 includes a first transistor TRA1, a second transistor TRA2, and a charge pump control circuit 162. The first transistor TRA1 is a P-type transistor, with its source connected to the output node NVRG of the regulator 110 and its drain connected to the terminal TCHP1. The second transistor TRA2 is an N-type transistor, with its source connected to the ground node and its drain connected to the terminal TCHP1.

[0095] The gate control circuit 170 includes a first diode DI1, a second diode DI2, and a resistor RB. The anode of the first diode DI1 is connected to the terminal TCHP2, and the cathode is connected to the terminal TDRV. The anode of the second diode DI2 is connected to the terminal TVCO, and the cathode is connected to the terminal TCHP2. The first diode DI1 and the second diode DI2 are, for example, Schottky barrier diodes. One end of the resistor RB is connected to the cathode of the first diode DI1 and the terminal TDRV, and the other end is connected to the anode of the second diode DI2 and the terminal TVCO.

[0096] The operation of the charge pump circuit 120 will be described. Hereinafter, the forward voltages of the first diode DI1 and the second diode DI2 will be ignored for the description.

[0097] The charge pump control circuit 162 alternately turns on the first transistor TRA1 and the second transistor TRA2. When the first transistor TRA1 is off and the second transistor TRA2 is on, the drive signal CHP1 is 0V. At this time, the signal CHP2 has the same voltage as the source voltage VCO due to the second diode DI2. When the first transistor TRA1 turns on from off and the second transistor TRA2 turns off from on, the drive signal CHP1 rises from 0V to the regulated voltage VRG. As a result, the signal CHP2 becomes a voltage that is higher than the source voltage VCO by the regulated voltage VRG.

[0098] This voltage VCO + VRG is the gate control voltage DRV and is output to the gate of the external transistor 11 via the first diode DI1. The gate of the external transistor 11 is charged by the charge supplied by the drive circuit 160, and in the steady state, the gate control voltage DRV is maintained at VCO + VRG.

[0099] When the charge pump circuit 120 stops, the charge pump control circuit 162 does not drive the first transistor TRA1 and the second transistor TRA2. For example, the charge pump control circuit 162 keeps the first transistor TRA1 on and the second transistor TRA2 off. After the charge pump circuit 120 stops, the voltage between the gate and source of the external transistor 11 becomes 0V due to the resistor RB.

[0100] The circuit device of the present embodiment described above includes a control circuit that controls the transistor current flowing through the transistor during charging based on the detected temperature detected by a temperature sensor circuit that detects the temperature of the transistor that charges the load to which the power supply voltage is supplied. When the detected temperature is higher than the first threshold value, the control circuit decreases the transistor current, and when the detected temperature is lower than the second threshold value that is lower than the first threshold value, the control circuit increases the transistor current.

[0101] According to the present embodiment, when the detected temperature becomes higher than the first threshold value, the transistor current decreases, so the temperature of the transistor drops. Thereby, the transistor can be protected from overheating. Also, when the detected temperature becomes lower than the second threshold value, the transistor current increases, so the transistor current is controlled so that the detected temperature is in the range from the second threshold value to the first threshold value. Thereby, within a range that does not exceed the first threshold value which is the allowable temperature, the transistor can charge the capacitance of the load node with a transistor current that is as large as possible.

[0102] The circuit device according to the present embodiment also includes a control circuit that controls a transistor current flowing through a transistor in discharging based on a detected temperature detected by a temperature sensor circuit that detects the temperature of a transistor that discharges from a load to which a power supply voltage is supplied. When the detected temperature is higher than a first threshold value, the control circuit decreases the transistor current, and when the detected temperature is lower than a second threshold value lower than the first threshold value, the control circuit increases the transistor current.

[0103] According to the present embodiment, when the detected temperature becomes higher than the first threshold value, the transistor current decreases, so that the temperature of the transistor drops. Thereby, the transistor can be protected from overheating. Further, when the detected temperature becomes lower than the second threshold value, the transistor current increases, so that the transistor current is controlled so that the detected temperature is in the range from the second threshold value to the first threshold value. Thereby, within a range not exceeding the first threshold value which is the allowable temperature, the transistor can discharge from the capacitance of the load node with a transistor current as large as possible.

[0104] Also, in the present embodiment, the control circuit may perform control to set the transistor current to a first current value, a second current value smaller than the first current value, or a third current value smaller than the second current value. When the transistor current is the second current value and the detected temperature is higher than the first threshold value, the control circuit may perform control to set the transistor current to the third current value. When the transistor current is the second current value and the detected temperature is lower than the second threshold value, the control circuit may perform control to set the transistor current to the first current value.

[0105] According to the present embodiment, when the detected temperature is higher than the first threshold value, the control circuit can decrease the transistor current by changing the transistor current from the second current value to the third current value. Further, when the detected temperature is lower than the second threshold value, the control circuit can increase the transistor current by changing the transistor current from the second current value to the first current value.

[0106] Also, in this embodiment, the control circuit may perform control to set the transistor current to a second current value when the transistor current is a first current value and the detected temperature is higher than a first threshold value. After a first period has elapsed since the control circuit sets the transistor current to the second current value, the control circuit determines whether the detected temperature is higher than the first threshold value. When it is determined that the detected temperature is higher than the first threshold value, the control circuit may set the transistor current to a third current value.

[0107] According to this embodiment, when the temperature turns to decrease after the transistor current has decreased to the second current value, since a first period is provided to wait until the temperature drops below the first threshold value, the transistor current does not decrease to the third current value. Thereby, in a situation where the temperature decreases when the transistor current is the second current value, the transistor current can be transitioned between two states, that is, between the first current value and the second current value.

[0108] Also, in this embodiment, the control circuit may perform control to set the transistor current to the second current value when the transistor current is the third current value and the detected temperature is lower than a second threshold value. After a second period has elapsed since the control circuit sets the transistor current to the second current value, the control circuit determines whether the detected temperature is lower than the second threshold value. When it is determined that the detected temperature is lower than the second threshold value, the control circuit may perform control to set the transistor current to the first current value.

[0109] According to this embodiment, when the temperature turns to increase after the transistor current has increased to the second current value, since a second period is provided to wait until the temperature exceeds the second threshold value, the transistor current does not increase to the first current value. Thereby, in a situation where the temperature increases when the transistor current is the second current value, the transistor current can be transitioned between two states, that is, between the third current value and the second current value.

[0110] Also, in this embodiment, the length of the second period may be longer than the length of the first period.

[0111] Since the heat of the transistor diffuses into the surroundings, it is assumed that the rate at which the temperature of the transistor rises is slower than the rate at which the temperature of the transistor falls. For this reason, by setting the second period for waiting for the detected temperature to exceed the second threshold value to be longer than the first period for waiting for the detected temperature to fall below the first threshold value, appropriate weight control is realized.

[0112] Also, in the present embodiment, the transistor may be connected in parallel to an external transistor provided between the power supply voltage node and the load node. The transistor may charge the load before the external transistor turns on.

[0113] By connecting the transistor in parallel to the external transistor, the load can be charged by the transistor current of the transistor before the external transistor turns on. According to the present embodiment, it is possible to achieve both protection of the transistor from overheating and charging as fast as possible within the range where it can be protected.

[0114] Also, in the present embodiment, the transistor may be provided between the load node and the ground node. The transistor may discharge the load after the external transistor provided between the power supply voltage node and the load node turns off.

[0115] By providing the transistor between the load node and the ground node, the load can be discharged by the transistor current of the transistor after the external transistor turns off. According to the present embodiment, it is possible to achieve both protection of the transistor from overheating and discharging as fast as possible within the range where it can be protected.

[0116] Also, the circuit device of the present embodiment may include a transistor and a temperature sensor circuit.

[0117] Although the present embodiment has been described in detail as above, those skilled in the art will easily understand that many modifications can be made without substantially departing from the novel matters and effects of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure. For example, in the specification or drawings, a term that has been described at least once together with a broader or synonymous different term can be replaced with that different term anywhere in the specification or drawings. Also, all combinations of the present embodiment and the modifications are included within the scope of the present disclosure. Further, the configurations and operations of the charging circuit, discharging circuit, regulator, charge pump circuit, circuit device, load, and electronic device, etc. are not limited to those described in the present embodiment, and various modified implementations are possible.

Explanation of Reference Numerals

[0118] 10... Electronic device, 11... External transistor, 12... Boost capacitor, 100... Circuit device, 110... Regulator, 120... Charge pump circuit, 140... Reference voltage generation circuit, 160... Drive circuit, 162... Charge pump control circuit, 170... Gate control circuit, 180... Charging circuit, 181... High-temperature side temperature detection circuit, 182... Low-temperature side temperature detection circuit, 183... Protection temperature detection circuit, 185... Control circuit, 186... State control circuit, 187... Constant current control circuit, 188... Temperature sensor circuit, 189... Transistor, 190... Discharging circuit, 191... High-temperature side temperature detection circuit, 192... Low-temperature side temperature detection circuit, 193... Protection temperature detection circuit, 195... Control circuit, 196... State control circuit, 197... Constant current control circuit, 198... Temperature sensor circuit, 199... Transistor, 300... Load, I1... First current value, I2... Second current value, I3... Third current value, NLOAD... Node, NVCC... Power supply node, TH... First threshold value, TL... Second threshold value, Tmax... Third threshold value, Tmin... Fourth threshold value, VCC... Power supply voltage, VCO... Source voltage, VH... First reference voltage, VL... Second reference voltage, VTA, VTB... Temperature detection voltage, VTSD... Third reference voltage, Vmin... Fourth reference voltage, WAIT1... First period, WAIT2... Second period

Claims

1. A control circuit that controls a transistor current flowing through the transistor in the charging based on a detected temperature detected by a temperature sensor circuit that detects the temperature of a transistor that charges a load to which a power supply voltage is supplied, wherein the control circuit, performs control to set the transistor current to a first current value, a second current value smaller than the first current value, or a third current value smaller than the second current value, when the transistor current is the first current value and the detected temperature is higher than a first threshold value, performs control to set the transistor current to the second current value, when the transistor current is the second current value and the detected temperature is higher than the first threshold value, performs control to set the transistor current to the third current value, and when the transistor current is the second current value and the detected temperature is lower than a second threshold value lower than the first threshold value, performs control to set the transistor current to the first current value. A circuit device characterized by this.

2. A control circuit that controls a transistor current flowing through the transistor in the discharging based on a detected temperature detected by a temperature sensor circuit that detects the temperature of a transistor that discharges a load to which a power supply voltage is supplied, wherein the control circuit, performs control to set the transistor current to a first current value, a second current value smaller than the first current value, or a third current value smaller than the second current value, when the transistor current is the first current value and the detected temperature is higher than a first threshold value, performs control to set the transistor current to the second current value, when the transistor current is the second current value and the detected temperature is higher than the first threshold value, performs control to set the transistor current to the third current value, and when the transistor current is the second current value and the detected temperature is lower than a second threshold value lower than the first threshold value, performs control to set the transistor current to the first current value. A circuit device characterized by this.

3. In the circuit device according to claim 1 or 2, the control circuit, After a first period has elapsed since the transistor current is set to the second current value, it is determined whether the detected temperature is higher than the first threshold value. When it is determined that the detected temperature is higher than the first threshold value, the transistor current is set to the third current value. A circuit device characterized by that.

4. In the circuit device according to claim 3, The control circuit, When the transistor current is the third current value and the detected temperature is lower than the second threshold value, control is performed to set the transistor current to the second current value, After a second period has elapsed since the transistor current is set to the second current value, it is determined whether the detected temperature is lower than the second threshold value. When it is determined that the detected temperature is lower than the second threshold value, control is performed to set the transistor current to the first current value. A circuit device characterized by that.

5. In the circuit device according to claim 4, The length of the second period is longer than the length of the first period. A circuit device characterized by that.

6. In the circuit device according to claim 1, The transistor is connected in parallel to an external transistor provided between the node of the power supply voltage and the node of the load, The transistor, A circuit device characterized by charging the load before the external transistor is turned on.

7. In the circuit device according to claim 2, The transistor is provided between the node of the load and the ground node, The transistor, A circuit device characterized by discharging the load after the external transistor provided between the node of the power supply voltage and the node of the load is turned off.

8. Including a control circuit that controls the transistor current flowing through the transistor in the charging based on the detected temperature detected by a temperature sensor circuit that detects the temperature of a transistor that charges a load to which a power supply voltage is supplied, The control circuit, When the detected temperature is higher than the first threshold value, the transistor current is decreased. When the detected temperature is lower than the second threshold value that is lower than the first threshold value, the transistor current is increased, The transistor is connected in parallel to an external transistor provided between the node of the power supply voltage and the node of the load, The transistor, A circuit device characterized by charging the load before the external transistor is turned on. **Claim 9** including a control circuit that controls a transistor current flowing through the transistor in the discharge based on a detected temperature detected by a temperature sensor circuit that detects a temperature of a transistor that discharges from a load to which a power supply voltage is supplied; the control circuit is when the detected temperature is higher than a first threshold value, decreasing the transistor current, and when the detected temperature is lower than a second threshold value lower than the first threshold value, increasing the transistor current; the transistor is provided between a node of the load and a ground node; the transistor is A circuit device characterized by discharging the load after an external transistor provided between a node of the power supply voltage and a node of the load is turned off. **Claim 10** In the circuit device according to any one of claims 1 to 9, the transistor; the temperature sensor circuit; A circuit device characterized by including the above.

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