Semiconductor devices, IPS with temperature-dependent compensation function, and inverter devices

Abstract

To improve the operational accuracy of a device having a semiconductor element having temperature dependence.SOLUTION: A semiconductor element 1a is an element that has temperature dependence and a characteristic of its output current decreasing as the temperature rises. A temperature detection circuit 11 detects temperature and outputs a temperature detection signal according to the detected temperature. A correction circuit 12 corrects the characteristic of the semiconductor element 1a based on the temperature detection signal. When the temperature of the semiconductor element 1a is a temperature Ta, a current Ia1 is output from the semiconductor element 1a. When the temperature of the semiconductor element 1a rises to a temperature Tb, the temperature detection circuit 11 detects the temperature Tb and outputs a temperature detection signal d1. Upon receiving the temperature detection signal d1, the correction circuit 12 outputs a correction current ic1. The current flowing to the output terminal of the semiconductor element 1a then increases to a current Ia2, which is obtained by adding the correction current ic1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a semiconductor device, an IPS with a temperature-dependent correction function, and an inverter device.

Background Art

[0002] In recent years, the development of a semiconductor device called an IPS (Intelligent Power Switch), which integrates a switching element using a power semiconductor device, a drive circuit for the switching element, and a protection circuit around it on one chip, has been progressing.

[0003] The IPS is widely used in vehicle electrical systems such as transmissions, engines, and brakes, and there is a demand for products that meet miniaturization, high performance, and high reliability.

[0004] FIG. 21 is a diagram showing an example of the configuration of a conventional IPS. It shows a schematic circuit configuration around the output stage of the high-side IPS. The IPS100a includes an input terminal IN, an output terminal OUT, a power supply terminal VT, and a ground terminal GND.

[0005] A pulsed control signal output from a microcomputer or the like is input to the input terminal IN. A load 200 is connected to the output terminal OUT. A power supply voltage VCC is connected to the power supply terminal VT, and a ground (GND) is connected to the ground terminal GND.

[0006] The IPS100a includes an output element M0, a logic circuit 110, a gate driver 120, and an overcurrent detection circuit 130a. The output element M0 is a power semiconductor element that drives the load 200, and in the example of the figure, an NMOS transistor, which is an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), is used.

[0007] The logic circuit 110 receives a control signal input through the input terminal IN and generates a logic signal to turn the output element M0 on or off. The gate driver 120 generates a drive signal to turn the output element M0 on or off based on the logic signal output from the logic circuit 110 and applies it to the gate of the output element M0.

[0008] When the overcurrent detection circuit 130a detects that an abnormally large current, exceeding the rated value, has flowed through the output element M0 while the output element M0 is ON, it transmits an overcurrent detection signal s0 to the logic circuit 110 to indicate that an overcurrent has occurred.

[0009] When the output element M0 of the IPS100a is turned on, the output voltage VOUT applied to the output terminal OUT changes depending on the current flowing through the output element M0. Therefore, the overcurrent detection circuit 130a compares the power supply voltage VCC with the output voltage VOUT applied to the output terminal OUT to detect whether or not the output element M0 is in an overcurrent state. When the logic circuit 110 detects the overcurrent detection signal s0, it turns off the output element M0.

[0010] Figure 22 shows an example of a conventional IPS configuration. IPS100b is a device equipped with overcurrent protection, similar to IPS100a. Note that the same reference numerals are used for components identical to those in Figure 21, and redundant explanations are omitted.

[0011] The IPS100b comprises an output element M0, a sense element Ms, a resistor Rs, a logic circuit 110, a gate driver 120, and an overcurrent detection circuit 130b. An NMOS transistor is used for the sense element Ms.

[0012] When the output element M0 of the IPS100b is turned on, a current proportional to the current flowing through the output element M0 flows through the sense element Ms, and the current from the sense element Ms flows through the resistor Rs. Therefore, a voltage drop occurs between one end of the resistor Rs connected to the source of the sense element Ms and the other end of the resistor Rs connected to the output terminal OUT. Furthermore, the voltage drop increases as the current flowing through the output element M0 increases.

[0013] The overcurrent detection circuit 130b monitors this voltage drop (corresponding to the potential difference across the resistor Rs based on the current flowing through the sense element Ms when the output element M0 is turned on), and detects whether or not the output element M0 is in an overcurrent state based on the monitored voltage drop.

[0014] Related technologies include, for example, a technique that determines whether or not a switching element is supplying overcurrent based on an added output voltage obtained by adding a detection voltage (which is obtained by converting the detection current of a switching element into a voltage) and a temperature correction voltage (which cancels out the temperature dependence of the detection voltage) (Patent Document 1). Another technique has been proposed that generates a correction table showing the correspondence between measurement data and temperature data, and outputs the read temperature data when the temperature data read from the correction table matches the measurement data (Patent Document 2). [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Japanese Patent Publication No. 2006-211834 [Patent Document 2] Japanese Patent Publication No. 2011-086742 [Overview of the Initiative] [Problems that the invention aims to solve]

[0016] In the IPS100a and 100b described above, for example, if load 200 is short-circuited, an excessive current greater than that during normal operation may flow, potentially causing failure of the output element M0 and surrounding circuits. Therefore, the IPS100a and 100b are equipped with a function to detect and protect against such overcurrents as part of their fault tolerance design.

[0017] However, some of the semiconductor elements that make up the overcurrent detection circuits 130a and 130b have temperature dependence, meaning their characteristics change with temperature. As a result, the characteristics of the semiconductor elements also change with temperature, which leads to a problem of reduced operational accuracy of the device.

[0018] In one aspect, the present invention aims to provide a semiconductor device, an IPS with a temperature-dependent semiconductor element, and an inverter device that improve the operating accuracy of such devices. [Means for solving the problem]

[0019] To solve the above problems, a semiconductor device is provided. The semiconductor device comprises a semiconductor element, a temperature detection circuit, and a correction circuit. The semiconductor element has a temperature dependence and a characteristic in which the output current changes with temperature. The temperature detection circuit detects the temperature and outputs a temperature detection signal corresponding to the detected temperature. The correction circuit corrects the characteristics of the semiconductor element based on the temperature detection signal. The temperature detection circuit includes a constant current source for temperature detection, a detection circuit including a temperature sense diode whose temperature detection voltage based on the current from the constant current source for temperature detection decreases as the temperature rises, a reference voltage generation unit that generates a reference voltage based on the current from the constant current source for temperature detection, and a comparison circuit that compares the reference voltage with the temperature detection voltage and outputs a temperature detection signal at a predetermined level when the reference voltage is higher than the temperature detection voltage. The constant current source for temperature detection includes a first constant current source and a second constant current source, the reference voltage generation unit includes a total of n resistors connected in series from the first resistor to the nth (n is a natural number) resistor in order from the high potential side to the low potential side, and the comparison circuit includes a total of n comparators from the first comparator to the nth comparator. The input terminal of the current source is connected to the input terminal and power supply of the second constant current source; the output terminal of the first constant current source is connected to the anode of the temperature sense diode and the inverting input terminals of a total of n comparators from the first to the nth comparator; the output terminal of the second constant current source is connected to the non-inverting input terminal of the first comparator and one end of the first resistor; a first temperature detection signal of a predetermined level is output from the output terminal of the first comparator; the non-inverting input terminal of the kth comparator is directly connected to the high potential terminal of the kth resistor; a kth temperature detection signal of a predetermined level is output from the output terminal of the kth comparator depending on the set temperature (1 ≤ k ≤ n); and the other end of the nth resistor is connected to the cathode and ground of the temperature sense diode.

[0020] Furthermore, an overcurrent detection circuit is provided that uses the semiconductor element as a component. The overcurrent detection circuit detects overcurrent in the current path when the potential difference between two points, the first terminal and the second terminal of the current path, exceeds a detection threshold.

[0021] In the above overcurrent detection circuit, an IPS with a temperature dependence correction function is provided. The IPS with a temperature dependence correction function has an output element, an overcurrent detection circuit, and a temperature compensation circuit. The temperature compensation circuit includes a temperature detection circuit and a correction circuit. The output element is connected to a power supply voltage via a first terminal and to a load via a second terminal, and switches based on a drive signal to operate the load. The overcurrent detection circuit performs overcurrent detection using, as a detection threshold for overcurrent, the potential difference between the power supply voltage and the output voltage applied from the second terminal to the load, which is determined by the on-resistance of the output element and the current flowing through the output element, and has a semiconductor element. The temperature detection circuit detects the temperature of a semiconductor element having a characteristic in which the output current changes according to a temperature change with temperature dependence, and outputs a temperature detection signal corresponding to the detected temperature. The correction circuit corrects the characteristics of the semiconductor element based on the temperature detection signal.

[0022] Furthermore, in order to solve the above problems, an inverter device is provided. The inverter device has an output element, a constant current source, a temperature detection circuit, and a correction circuit. The output element switches based on a drive signal. The constant current source has a characteristic in which the output current changes according to a temperature change with temperature dependence. The temperature detection circuit detects the temperature of the constant current source and outputs a temperature detection signal corresponding to the detected temperature. The correction circuit corrects the characteristics of the constant current source based on the temperature detection signal.

Advantages of the Invention

[0023] According to one aspect, it becomes possible to improve the operation accuracy of a device having a semiconductor element with temperature dependence.

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram for explaining an example of a semiconductor device. [Figure 2] It is a diagram showing an example of the configuration of a temperature detection circuit. [Figure 3] It is a diagram showing an example of the configuration of a correction circuit. [Figure 4] It is a diagram showing an example of the configuration of an IPS with an overcurrent detection circuit. [Figure 5] This figure shows an example of the configuration of an overcurrent detection circuit. [Figure 6] This figure shows a modified example of an overcurrent detection circuit. [Figure 7] This is a diagram illustrating the overcurrent detection threshold. [Figure 8] This is a diagram illustrating the operation of the overcurrent detection circuit. [Figure 9] This is a time chart showing the operation of the overcurrent detection circuit. [Figure 10] This figure shows an example configuration of an IPS with an overcurrent protection circuit that has a temperature compensation function. [Figure 11] This figure shows an example of the configuration of an overcurrent protection circuit. [Figure 12] This is a diagram showing an example of the configuration of a correction circuit. [Figure 13] This figure shows a modified example of an overcurrent protection circuit. [Figure 14] This shows an example of a waveform during temperature compensation. [Figure 15] This diagram illustrates the temperature dependence of the overcurrent detection threshold. [Figure 16] This diagram illustrates the suppression of detection threshold fluctuations through temperature compensation. [Figure 17] This figure shows an example of the configuration of an inverter device. [Figure 18] This diagram shows a modified example of an inverter device. [Figure 19] This figure shows a modified example of an overcurrent protection circuit. [Figure 20] This figure shows a modified example of an overcurrent protection circuit. [Figure 21] This figure shows an example of a conventional IPS configuration. [Figure 22] This figure shows an example of a conventional IPS configuration. [Modes for carrying out the invention]

[0025] This embodiment will now be described with reference to the drawings. Note that elements having substantially the same function in this specification and the drawings may be denoted by the same reference numerals, thus omitting redundant explanations.

[0026] Figure 1 is a diagram illustrating an example of a semiconductor device. The semiconductor device 1 is a device that has a temperature compensation function and comprises a semiconductor element 1a, a temperature detection circuit 11, and a correction circuit 12. The semiconductor element 1a is a temperature-dependent element that has the characteristic of changing output current with temperature changes. The temperature detection circuit 11 detects the temperature and outputs a temperature detection signal corresponding to the detected temperature. The correction circuit 12 corrects the characteristics of the semiconductor element 1a based on the temperature detection signal.

[0027] [Temperature Ta] When the temperature of semiconductor element 1a is temperature Ta, a current Ia1 is output from semiconductor element 1a. Note that semiconductor element 1a has a temperature dependence, meaning the output current decreases as the temperature rises. Therefore, as shown in the figure, the output current gradually decreases from current Ia1 as the temperature rises.

[0028] [Temperature Tb] The temperature of the semiconductor element 1a rises to temperature Tb. In this case, the temperature detection circuit 11 detects temperature Tb and outputs a temperature detection signal d1. When the correction circuit 12 receives the temperature detection signal d1, it outputs a correction current ic1. Then, the correction current ic1 is added to the current flowing at the output terminal of the semiconductor element 1a, increasing it to current Ia2. Note that current Ia2 also decreases as the temperature rises.

[0029] [Temperature Tc] The temperature of the semiconductor element 1a rises to temperature Tc. In this case, the temperature detection circuit 11 detects temperature Tc and outputs a temperature detection signal d2. Note that the output of temperature detection signal d1 is maintained. When the correction circuit 12 receives the temperature detection signal d2, it outputs a correction current ic2 in addition to the correction current ic1. Then, the correction current ic2 is added to the current flowing at the output terminal of the semiconductor element 1a, increasing it to current Ia3. Also, current Ia3 decreases as the temperature rises.

[0030] [Temperature Td] The temperature of the semiconductor element 1a rises to temperature Td. In this case, the temperature detection circuit 11 detects temperature Td and outputs a temperature detection signal d3. The outputs of temperature detection signals d1 and d2 are maintained. When the correction circuit 12 receives the temperature detection signal d3, it outputs a correction current ic3 in addition to the correction currents ic1 and ic2. Then, it adds the correction current ic3 to the current flowing at the output terminal of the semiconductor element 1a, increasing it to a current Ia4. The current Ia4 also decreases as the temperature rises.

[0031] Thus, the semiconductor device 1 is configured to detect the temperature of the object to be detected, generate a temperature detection signal corresponding to the detected temperature, and correct the characteristics of the semiconductor element 1a based on the temperature detection signal. This allows for temperature compensation of the semiconductor element 1a, making it possible to improve the operating accuracy of a device equipped with a temperature-dependent semiconductor element 1a even when there are temperature changes.

[0032] <Temperature detection circuit> Figure 2 shows an example of the configuration of a temperature detection circuit. The temperature detection circuit 11 comprises a constant current source 11a (constant current source for temperature detection), a reference voltage generation unit 11b, a detection circuit 11c, and a comparison circuit 11d. The constant current source 11a includes a constant current element 11a1 (first constant current element) and a constant current element 11a2 (second constant current element), and the reference voltage generation unit 11b includes resistors R1, ..., R4. Note that resistors R1, ..., R4 correspond to the first to fourth resistors, respectively.

[0033] The detection circuit 11c includes temperature sense diodes D1, ..., D4, whose temperature detection voltage based on the current from the constant current source 11a decreases as the temperature rises. The comparison circuit 11d includes comparators cmp1, ..., cmp4. Note that comparators cmp1, ..., cmp4 correspond to the first to fourth comparators, respectively.

[0034] In terms of the connection relationships of the constituent elements, the input terminal of constant current element 11a1 is connected to the input terminal of constant current element 11a2 and the power supply. The output terminal of constant current element 11a1 is connected to the anode of temperature sense diode D1, the inverting input terminal (-) of comparator cmp1, the inverting input terminal (-) of comparator cmp2, ​​the inverting input terminal (-) of comparator cmp3, and the inverting input terminal (-) of comparator cmp4.

[0035] The cathode of temperature sense diode D1 is connected to the anode of temperature sense diode D2, the cathode of temperature sense diode D2 is connected to the anode of temperature sense diode D3, and the cathode of temperature sense diode D3 is connected to the anode of temperature sense diode D4. Note that the number of temperature sense diodes D1, ..., D4 connected in series is not limited to four; any number can be used.

[0036] The output terminal of the constant current element 11a2 is connected to the non-inverting input terminal (+) of the comparator cmp1 and one end of resistor R1. The other end of resistor R1 is connected to one end of resistor R2 and the non-inverting input terminal (+) of the comparator cmp2.

[0037] The other end of resistor R2 is connected to one end of resistor R3 and the non-inverting input terminal (+) of comparator cmp3. The other end of resistor R3 is connected to one end of resistor R4 and the non-inverting input terminal (+) of comparator cmp4. The other end of resistor R4 is connected to the cathode of temperature sense diode D4 and GND.

[0038] Here, the current i1 flowing from the constant current element 11a1 to the temperature sense diodes D1, ..., D4 is a forward current to the temperature sense diodes D1, ..., D4. Therefore, the voltage at node n1 (temperature detection voltage) is the sum of the forward voltages (hereinafter referred to as forward voltage Vf) of each of the temperature sense diodes D1, ..., D4. For example, if the forward voltage Vf of each of the temperature sense diodes D1, ..., D4 is 0.8V, then the temperature detection voltage at node n1 will be 3.2 (= 0.8 × 4)V.

[0039] Furthermore, the temperature-sensing diodes D1, ..., D4 have temperature characteristics, and their forward voltage Vf changes with temperature. For example, when the temperature rises by 1°C, the forward voltage Vf decreases by approximately 2mV.

[0040] Therefore, for example, if the temperature rises from 25°C to 50°C, the decrease in the forward voltage Vf of one temperature sense diode will be 0.05 (= 0.002 × 25) V.

[0041] Therefore, if the forward voltage Vf at a temperature of 25°C is 0.8V, and the temperature rises to 50°C, the total decrease in the forward voltage Vf of temperature sense diodes D1, ..., D4 will be 0.2V (=0.05 × 4), and the temperature detection voltage at node n1 will be 3.0V (3.2 - 0.2).

[0042] Thus, the temperature detection voltage at node n1 is 3.2V when the temperature is 25°C and 3.0V when the temperature is 50°C. Therefore, it changes with temperature and decreases as the temperature rises.

[0043] On the other hand, when a current i2 is output from the constant current element 11a2 (currents i1 and i2 may be equal or different), and the voltage across node n2 is taken as voltage Vr1, the reference voltage Vr1 is input to the non-inverting input terminal (+) of the comparator cmp1.

[0044] Furthermore, the reference voltage Vr2 input to the non-inverting input terminal (+) of comparator cmp2 is obtained by resistive voltage division as follows: Vr2 = (R2 + R3 + R4) · Vr1 / (R1 + R2 + R3 + R4).

[0045] Furthermore, the reference voltage Vr3 input to the non-inverting input terminal (+) of comparator cmp3 is obtained by resistive voltage division as follows: Vr3 = (R3 + R4) · Vr1 / (R1 + R2 + R3 + R4).

[0046] Furthermore, the reference voltage Vr4 input to the non-inverting input terminal (+) of the comparator cmp4 is given by Vr4 = R4·Vr1 / (R1 + R2 + R3 + R4) due to resistor voltage division. Note that the magnitude relationship of the reference voltages Vr1, ···, Vr4 is Vr4 < Vr3 < Vr2 < Vr1.

[0047] Here, the temperature T to be detected is divided into four parts as temperature Tj1, ···, Tj4 (where Tj1 < Tj2 < Tj3 < Tj4). Also, the temperature detection voltage at node n1 in the case of temperature Tj1 is defined as temperature detection voltage Vt1, and the temperature detection voltage at node n1 in the case of temperature Tj2 is defined as temperature detection voltage Vt2.

[0048] Furthermore, the temperature detection voltage at node n1 in the case of temperature Tj3 is defined as temperature detection voltage Vt3, and the temperature detection voltage at node n1 in the case of temperature Tj4 is defined as temperature detection voltage Vt4. Note that the magnitude relationship of the temperature detection voltages Vt1, ···, Vt4 is Vt4 < Vt3 < Vt2 < Vt1.

[0049] In the temperature detection circuit 11, when the temperature T of the semiconductor element 1a to be temperature-detected is T < Tj1, L-level temperature detection signals A, B, C, D are respectively output from the comparators cmp1, cmp2, cmp3, cmp4.

[0050] Also, when the temperature T is Tj1 ≤ T < Tj2, the temperature detection voltage Vt1 becomes lower than the reference voltage Vr1 and higher than the reference voltages Vr2, Vr3, Vr4. An H-level temperature detection signal A is output from the comparator cmp1, and L-level temperature detection signals B, C, D are respectively output from the comparators cmp2, cmp3, cmp4.

[0051] Also, when the temperature rises to Tj2 ≤ T < Tj3, the temperature detection voltage Vt2 becomes lower than the reference voltages Vr1, Vr2 and higher than the reference voltages Vr3, Vr4. H-level temperature detection signals A, B are respectively output from the comparators cmp1, cmp2, and L-level temperature detection signals C, D are respectively output from the comparators cmp3, cmp4.

[0052] Furthermore, when the temperature rises and Tj3 ≤ T < Tj4, the temperature detection voltage Vt3 is lower than the reference voltages Vr1, Vr2, and Vr3 and higher than the reference voltage Vr4. High-level temperature detection signals A, B, and C are respectively output from the comparators cmp1, cmp2, and cmp3, and a low-level temperature detection signal D is output from the comparator cmp4.

[0053] Furthermore, when the temperature rises and Tj4 ≤ T, the temperature detection voltage Vt4 is lower than the reference voltages Vr1, Vr2, Vr3, and Vr4, and high-level temperature detection signals A, B, C, and D are respectively output from the comparators cmp1, cmp2, cmp3, and cmp4.

[0054] As described above, in the temperature detection circuit 11, as the temperature rises, high-level (predetermined level) temperature detection signals are sequentially output from the comparators cmp1, ···, cmp4. Regarding the outputs of the comparators cmp1, ···, cmp4 as digital logic outputs (high level is 1, low level is 0), and denoting the outputs of the comparators cmp1, ···, cmp4 as (A, B, C, D), when the temperature T of the semiconductor element 1a to be temperature-detected is T < Tj1, (A, B, C, D) = (0, 0, 0, 0).

[0055] Also, when the temperature T is Tj1 ≤ T < Tj2, (A, B, C, D) = (1, 0, 0, 0), and when the temperature T is Tj2 ≤ T < Tj3, (A, B, C, D) = (1, 1, 0, 0). Furthermore, when the temperature T is Tj3 ≤ T < Tj4, (A, B, C, D) = (1, 1, 1, 0), and when the temperature T is Tj4 ≤ T, (A, B, C, D) = (1, 1, 1, 1).

[0056] As described above, the temperature detection circuit 11 outputs n temperature detection signals for each temperature divided into n (n is a natural number) levels. In the above example of n = 4, since the temperature is divided into 4 levels, 4 temperature detection signals A, B, C, and D are output.

[0057] Furthermore, the reference voltage generation unit 11b generates n reference voltages based on the current from the constant current source 11a, and generates reference voltages in which the voltage value decreases from the first to the k (1≦k≦n)th reference voltage.

[0058] In the above example where n=4, the following reference voltages are generated: the first reference voltage Vr1, the second reference voltage Vr2, the third reference voltage Vr3, and the fourth reference voltage Vr4 (Vr4 <Vr3<Vr2<Vr1)。

[0059] Furthermore, the comparison circuit 11d compares the k-th (1 ≤ k ≤ n) reference voltage out of n with the temperature detection voltage, and outputs a temperature detection signal for the k-th or lower if the k-th reference voltage is higher than the temperature detection voltage.

[0060] In the above example where n=4, the first of the four reference voltages, Vr1, is compared with the temperature detection voltage. If the first reference voltage is higher than the temperature detection voltage, the first temperature detection signal A (high-level temperature detection signal A) is output. Additionally, the second of the four reference voltages, Vr2, is compared with the temperature detection voltage. If the second reference voltage Vr2 is higher than the temperature detection voltage, the second and subsequent (first and second) temperature detection signals A and B (high-level temperature detection signals A and B) are output.

[0061] Furthermore, the third of the four reference voltages, Vr3, is compared with the temperature detection voltage. If the third reference voltage Vr3 is higher than the temperature detection voltage, the third and subsequent (first, second, and third) temperature detection signals A, B, and C (high-level temperature detection signals A, B, and C) are output. Additionally, the fourth of the four reference voltages, Vr4, is compared with the temperature detection voltage. If the fourth reference voltage Vr4 is higher than the temperature detection voltage, the fourth and subsequent (first, second, third, and fourth) temperature detection signals A, B, C, and D (high-level temperature detection signals A, B, C, and D) are output.

[0062] <Correction Circuit> Figure 3 shows an example of the configuration of a correction circuit. The correction circuit 12 includes a correction current source 12a and a switch circuit 12b. The main current source Im corresponds to the semiconductor element 1a to be current-corrected.

[0063] The correction current source 12a includes correction current elements Ic1, ..., Ic4, and the switch circuit 12b includes switches sw1, ..., sw4. The main current source Im outputs the main current im1, and the correction current elements Ic1, ..., Ic4 each output the correction currents ic1, ..., ic4.

[0064] In the connection of the constituent elements, the input terminal of the main current source Im is connected to the input terminals of the power supply and the respective correction current elements Ic1, ..., Ic4. The output terminal of correction current element Ic1 is connected to terminal a1 of switch sw1, and the output terminal of correction current element Ic2 is connected to terminal a2 of switch sw2. The output terminal of correction current element Ic3 is connected to terminal a3 of switch sw3, and the output terminal of correction current element Ic4 is connected to terminal a4 of switch sw4. Terminals a1, ..., a4 correspond to the first terminal.

[0065] The output terminal of the main current source Im is connected to terminal b1 of switch sw1, terminal b2 of switch sw2, terminal b3 of switch sw3, terminal b4 of switch sw4, and GND. Note that terminals b1, ..., b4 correspond to the second terminal.

[0066] Terminal c1 of switch sw1 is connected to the output terminal of comparator cmp1, and temperature detection signal A is input. Terminal c2 of switch sw2 is connected to the output terminal of comparator cmp2, ​​and temperature detection signal B is input. Terminal c3 of switch sw3 is connected to the output terminal of comparator cmp3, and temperature detection signal C is input. Terminal c4 of switch sw4 is connected to the output terminal of comparator cmp4, and temperature detection signal D is input. Note that terminals c1, ..., c4 correspond to control terminals.

[0067] Here, the main current source Im is a semiconductor element 1a having temperature dependence. For example, when the main current source Im is composed of a MOS transistor or the like, the temperature dependence is remarkable. In such a main current source Im having temperature dependence, the main current im1 output from the main current source Im may decrease as the temperature rises. Therefore, the correction circuit 12 performs correction control to compensate for the current decrease accompanying the temperature rise and maintain the original current.

[0068] Regarding the switching of the switches sw1, ···, sw4, the switch sw1 turns on when a high-level temperature detection signal A is input from the comparator cmp1, and turns off when a low-level temperature detection signal A is input. The switch sw2 turns on when a high-level temperature detection signal B is input from the comparator cmp2, and turns off when a low-level temperature detection signal B is input.

[0069] Similarly, the switch sw3 turns on when a high-level temperature detection signal C is input from the comparator cmp3, and turns off when a low-level temperature detection signal C is input. The switch sw4 turns on when a high-level temperature detection signal D is input from the comparator cmp4, and turns off when a low-level temperature detection signal D is input.

[0070] In the current correction of the correction circuit 12, when the temperature T of the main current source Im to be temperature-detected is T < Tj1, the outputs of the comparators cmp1, ···, cmp4 are all at the low level, so the switches sw1, ···, sw4 are off. Therefore, the main current im1 is output from the main current source Im.

[0071] Also, when the temperature T satisfies Tj1 ≦ T < Tj2, a high-level temperature detection signal A is output from the comparator cmp1, and low-level temperature detection signals B, C, and D are respectively output from the comparators cmp2, cmp3, and cmp4. Therefore, the switch sw1 is turned on, and the switches sw2, sw3, and sw4 are turned off. Thus, at the output terminal of the main current source Im, a correction current ic1 output from the correction current element Ic1 is added to the main current im1.

[0072] Furthermore, when the temperature T satisfies Tj2 ≦ T < Tj3, high-level temperature detection signals A and B are respectively output from the comparators cmp1 and cmp2, and low-level temperature detection signals C and D are respectively output from the comparators cmp3 and cmp4. Therefore, the switches sw1 and sw2 are turned on, and the switches sw3 and sw4 are turned off. Thus, at the output terminal of the main current source Im, a correction current ic2 output from the correction current element Ic2 is added to the total current of the main current im1 and the correction current ic1.

[0073] Also, when the temperature T satisfies Tj3 ≦ T < Tj4, high-level temperature detection signals A, B, and C are respectively output from the comparators cmp1, cmp2, and cmp3, and a low-level temperature detection signal D is output from the comparator cmp4 Out is output. Therefore, the switches sw1, sw2, and sw3 are turned on, and the switch sw4 is turned off. Thus, at the output terminal of the main current source Im, a correction current ic3 output from the correction current element Ic3 is added to the total current of the main current im1, the correction current ic1, and the correction current ic2.

[0074] Moreover, when the temperature T satisfies Tj4 ≦ T, high-level temperature detection signals A, B, C, and D are respectively output from the comparators cmp1, cmp2, cmp3, and cmp4. Therefore, the switches sw1, sw2, sw3, and sw4 are turned on. Thus, at the output terminal of the main current source Im, a correction current ic4 output from the correction current element Ic4 is added to the total current of the main current im1, the correction current ic1, the correction current ic2, and the correction current ic3.

[0075] Thus, the correction circuit 12 includes a correction current source 12a containing n correction current elements, and a switch circuit 12b containing n switches that switch the output of the correction current source 12a.

[0076] In the above example where n=4, the components include correction current elements Ic1, ..., Ic4 and switches sw1, ..., sw4. Furthermore, when a temperature detection signal of a predetermined level below the kth element is output, the switches below the kth element are turned on, and a correction current is output from the correction current elements below the kth element.

[0077] In the above example where n=4, when the first H-level temperature detection signal A is output, the first switch sw1 turns on and the first correction current element Ic1 outputs a correction current ic1.

[0078] Furthermore, when the second and subsequent (first and second) H-level temperature detection signals A and B are output, the second and subsequent (first and second) switches sw1 and sw2 are turned on, and the second and subsequent (first and second) correction current elements Ic1 and Ic2 output correction currents ic1 and ic2.

[0079] Furthermore, when the third and subsequent (1st, 2nd, 3rd) H-level temperature detection signals A, B, and C are output, the third and subsequent (1st, 2nd, 3rd) switches sw1, sw2, and sw3 are turned on, and the third and subsequent (1st, 2nd, 3rd) correction current elements Ic1, Ic2, and Ic3 output correction currents ic1, ic2, and ic3.

[0080] Furthermore, when the fourth and subsequent (1st, 2nd, 3rd, 4th) H-level temperature detection signals A, B, C, and D are output, the fourth and subsequent (1st, 2nd, 3rd, 4th) switches sw1, sw2, sw3, and sw4 are turned on, and the fourth and subsequent (1st, 2nd, 3rd, 4th) correction current elements Ic1, Ic2, Ic3, and Ic4 output correction currents ic1, ic2, ic3, and ic4.

[0081] Thus, in the correction circuit 12, even if the current output from the main current source Im decreases as the temperature rises, the correction current source 12a can compensate for the decreased current at the output terminal of the main current source Im, which has a temperature dependence.

[0082] <IPS with overcurrent detection circuit> The semiconductor device 1 described above can be applied, for example, to an IPS with an overcurrent detection circuit. Therefore, the IPS with an overcurrent detection circuit to which the temperature compensation function of the semiconductor device 1 is applied will be described below. To make the explanation step by step, the configuration and operation of the IPS with an overcurrent detection circuit before the temperature compensation function of the semiconductor device 1 is applied will first be described using Figures 4 to 9.

[0083] Figure 4 shows an example of the configuration of an IPS with an overcurrent detection circuit. The IPS1-1 with an overcurrent detection circuit is included in an IPS (high-side IPS), for example, and has an input terminal IN, an output terminal OUT, a power supply terminal VT, and a ground terminal GND.

[0084] The input terminal IN is connected to the microcontroller 5, and the pulse-shaped control signal output from the microcontroller 5 is input. The output terminal OUT is connected to the load L0. Load L0 is, for example, an inductive load such as a solenoid valve widely used in automobiles, or a resistive load such as a heater. The power supply terminal VT is connected to the power supply voltage VCC, such as a battery, and the ground terminal GND is connected to GND.

[0085] The IPS1-1 with an overcurrent detection circuit comprises an output element M0, a logic circuit 21, a gate driver 22, and an overcurrent detection circuit 2a. The output element M0 is a power semiconductor element that drives the load L0, and in the example shown in the figure, an NMOS transistor is used. Alternatively, an IGBT (Insulated Gate Bipolar Transistor) may be used instead of the NMOS transistor.

[0086] The logic circuit 21 receives a control signal transmitted from the microcontroller 5 through the input terminal IN and generates a logic signal to turn the output element M0 on or off. For example, when the logic circuit 21 receives a high-level control signal input through the input terminal IN, it outputs a logic signal to turn on the output element M0.

[0087] The gate driver 22 generates a voltage to turn on the output element M0 based on the logic signal output from the logic circuit 21, applies it to the gate, and turns on the output element M0. Furthermore, when the logic circuit 21 receives an L-level control signal transmitted from the microcontroller 5 through the input terminal IN, it outputs a logic signal to turn off the output element M0. The gate driver 22 generates a signal at a level that turns off the output element M0 based on the logic signal output from the logic circuit 21, and applies it to the gate of the output element M0 to turn off the output element M0.

[0088] The overcurrent detection circuit 2a detects overcurrent in a current path when the potential difference between two points in the current path exceeds a detection threshold. In the case of the IPS1-1 with the overcurrent detection circuit, the overcurrent detection circuit 2a is connected between the power supply terminal VT and the output terminal OUT. When the output element M0 is turned on, if it detects that an abnormally large current flows through the output element M0, it sends an overcurrent detection signal s1 to the logic circuit 21. The overcurrent detection circuit 2a also detects overcurrent using the potential difference between the power supply voltage VCC and the output voltage applied from the output terminal OUT to the load L0, which is determined by the on-resistance of the output element M0 and the current flowing through the output element M0, as the overcurrent detection threshold.

[0089] Furthermore, when the logic circuit 21 receives the overcurrent detection signal s1 transmitted from the overcurrent detection circuit 2a, it outputs a logic signal to turn off the output element M0, and the gate driver 22 turns off the output element M0 based on the logic signal output from the logic circuit 21.

[0090] Figure 5 shows an example of the configuration of an overcurrent detection circuit. The overcurrent detection circuit 2a includes P-channel MOSFETs M1, ..., M4, NMOS transistors M5, M6, M7, and a constant current source IR1. PMOS transistors M1, M2, and M3 correspond to the first, second, and third PMOS transistors, respectively. NMOS transistors M5 and M6 correspond to the first and second NMOS transistors, respectively.

[0091] Regarding the connections of the constituent elements, the source of PMOS transistor M1 is connected to the back gate (body) of PMOS transistor M1, the power supply terminal VT, the back gate of PMOS transistor M2, the source (first high-potential terminal) of PMOS transistor M2, the back gate of PMOS transistor M3, the source of PMOS transistor M4, and the back gate of PMOS transistor M4. The source (second high-potential terminal) of PMOS transistor M3 is connected to the output terminal OUT.

[0092] The drain of PMOS transistor M1 is connected to the input terminal of constant current source IR1, the gate of PMOS transistor M1, the gate of PMOS transistor M2, the gate of PMOS transistor M3, and the gate of PMOS transistor M4.

[0093] The drain of PMOS transistor M2 is connected to the drain of NMOS transistor M5, the gate of NMOS transistor M5, and the gate of NMOS transistor M6. The drain of PMOS transistor M3 is connected to the drain of NMOS transistor M6 and the gate of NMOS transistor M7.

[0094] The drain of PMOS transistor M4 is connected to the drain of NMOS transistor M7. The output terminal of constant current source IR1 is connected to the source of NMOS transistor M5, the back gate of NMOS transistor M5, the source of NMOS transistor M6, the back gate of NMOS transistor M6, the source of NMOS transistor M7, the back gate of NMOS transistor M7, and GND.

[0095] The overcurrent detection signal s1, which indicates the result of overcurrent detection, is output from the connection node between the drain of PMOS transistor M4 and the drain of NMOS transistor M7. Meanwhile, a potential generation unit 2a1 is formed by a PMOS transistor M1 and a constant current source IR1, a detection unit 2a2 is formed by differential pair elements (pair elements) PMOS transistors M2 and M3 and current mirror NMOS transistors M5 and M6, and an output unit 2a3 is formed by a PMOS transistor M4 and an NMOS transistor M7.

[0096] Here, in the differential pair elements, PMOS transistors M2 and M3, if PMOS transistors M2 and M3 are the same size and the gate-source voltage VGS of PMOS transistors M2 and M3 is the same, then the same current will flow through PMOS transistors M2 and M3.

[0097] Therefore, by increasing or decreasing the size of PMOS transistors M2 and M3, a difference will be created in the gate-source voltage VGS required to supply the same amount of current to PMOS transistors M2 and M3. In the overcurrent detection circuit 2a, this difference in gate-source voltage VGS is used as the overcurrent detection threshold.

[0098] The overcurrent detection circuit 2a then detects the occurrence of an overcurrent by comparing the potential difference between the power supply terminal VT and the output terminal OUT (a potential difference proportional to the increase in current flowing through the output element M0) with a detection threshold which is the difference between the gate-source voltage VGS of PMOS transistor M2 and the gate-source voltage VGS of PMOS transistor M3.

[0099] FIG. 6 is a diagram showing a modified example of the overcurrent detection circuit. The overcurrent detection circuit 2a-1 has a circuit configuration that is a different version of the overcurrent detection circuit 2a shown in FIG. 5. In the overcurrent detection circuit 2a shown in FIG. 5, a constant current source is arranged on the GND side, whereas in the overcurrent detection circuit 2a-1 shown in FIG. 6, a constant current source is arranged on the power supply side. In the overcurrent detection circuit 2a-1 shown in FIG. 6, the first and second PMOS transistors respectively correspond to PMOS transistors M2 and M3, and the first to third NMOS transistors respectively correspond to NMOS transistors M1, M5, and M6.

[0100] <Overcurrent Detection Threshold> FIG. 7 is a diagram for explaining the overcurrent detection threshold. The vertical axis represents the drain current IDS (A), and the horizontal axis represents the gate-source voltage VGS (V). In this figure, the values are negative throughout the entire range. Let the drain current of PMOS transistor M2 be drain current IM2, and the drain current of PMOS transistor M3 be drain current IM3.

[0101] Also, let the gate-source voltage of PMOS transistor M2 be gate-source voltage VGS2, and the gate-source voltage of PMOS transistor M3 be gate-source voltage VGS3.

[0102] In the example of FIG. 7, when the drain currents IM2 and IM3 of PMOS transistors M2 and M3 respectively have the same value, the sizes of PMOS transistors M2 and M3 are adjusted so that the relationship VGS2 < VGS3 (in terms of absolute value, |VGS2| > |VGS3|) holds. At this time, the potential difference between the gate-source voltage VGS2 and the gate-source voltage VGS3 (the potential difference between the source voltages of PMOS transistors M2 and M3 respectively) becomes the detection threshold in the overcurrent detection of the overcurrent detection circuit 2a.

[0103] <Operation of the Overcurrent Detection Circuit> Figure 8 is a diagram illustrating the operation of the overcurrent detection circuit. The voltages at each node in Figure 8 of the overcurrent detection circuit 2a are denoted as voltages V1, ..., V6 (hereinafter, the power supply voltage VCC may be denoted as voltage V1 and the output voltage VOUT as voltage V2). Also, the drain current of PMOS transistor M2 is current I1, the drain current of PMOS transistor M3 is current I2, and the drain current of PMOS transistor M4 is current I3. Furthermore, it is assumed that the size of PMOS transistor M3 is larger than the size of PMOS transistor M2.

[0104] Figure 9 is a time chart showing the operation of the overcurrent detection circuit. (Overcurrent non-detection period t1 (normal operation period)) [State of voltages V1 and V2] Voltage V1 is the power supply voltage VCC applied from the power supply terminal VT, so it does not change. On the other hand, when the output element M0 connected between the power supply terminal VT and the output terminal OUT is turned on, current gradually flows through the output element M0, and as the current flowing through the output element M0 increases, voltage V2 decreases. The potential difference between voltages V1 and V2 is the detection threshold Vth. Furthermore, period t1 (the period during which no overcurrent occurs) is the period during which the potential difference between voltages V1 and V2 is less than the detection threshold Vth.

[0105] [State of voltage V3] Due to the current from the constant current source IR1, the gate potential of PMOS transistor M1 becomes lower than the source potential of PMOS transistor M1, so PMOS transistor M1 turns on. Voltage V3 becomes a constant voltage value determined by the on-resistance of PMOS transistor M1.

[0106] [State of voltage V4] Since voltage V3 is applied to the gate of PMOS transistor M2, the gate potential of PMOS transistor M2 is lower than the source potential of PMOS transistor M2, and PMOS transistor M2 turns on. Therefore, the current flowing through PMOS transistor M2 applies a voltage to the gate of NMOS transistor M5, so the gate potential of NMOS transistor M5 becomes higher than the source potential of NMOS transistor M5, and NMOS transistor M5 turns on.

[0107] Therefore, since the current I1 flows from the drain of the PMOS transistor M2 to the drain of the NMOS transistor M5, the voltage V4 generated at the gate of the NMOS transistor M5 is fixed as a constant voltage value that allows the current I1 to flow.

[0108] [State of voltage V5] Voltage V2 is applied to the source of PMOS transistor M3, and voltage V3 is applied to the gate of PMOS transistor M3. Voltage V2 is higher than voltage V3, so the gate potential of PMOS transistor M3 becomes lower than the source potential of PMOS transistor M3, and PMOS transistor M3 turns on.

[0109] Furthermore, since a voltage V4 is applied to the gate of NMOS transistor M6, the gate potential of NMOS transistor M6 becomes higher than the source potential of NMOS transistor M6, and NMOS transistor M6 turns on.

[0110] Therefore, when the potential difference between voltage V1 and voltage V2 is less than the detection threshold Vth, current I2 flows from the drain of PMOS transistor M3 to the drain of NMOS transistor M6, and voltage V5 is generated at the drain of NMOS transistor M6. Note that since voltage V2 decreases as described above, voltage V5 does not become flat but transitions in a downward direction.

[0111] [State of voltage V6] Current I3 flows from PMOS transistor M4 to the drain of NMOS transistor M7, so a voltage V6 is generated at the drain of NMOS transistor M7.

[0112] Furthermore, since a voltage V5 is applied to the gate of NMOS transistor M7, the gate potential of NMOS transistor M7 becomes higher than the source potential of NMOS transistor M7, and NMOS transistor M7 turns on.

[0113] Therefore, current I3 flows from PMOS transistor M4 to NMOS transistor M7. Also, a voltage V6 is generated at the drain of NMOS transistor M7, but NMOS transistor M7 is ON, and since the current that NMOS transistor M7 can supply is greater than the current from PMOS transistor M4, current I3 flows to GND, and voltage V6 becomes approximately at GND level.

[0114] Here, since a voltage V3 is applied to the gate of PMOS transistor M4, the gate potential of PMOS transistor M4 becomes lower than the source potential, and PMOS transistor M4 turns on. Therefore, current I3 flows from the drain of PMOS transistor M4 to the drain of NMOS transistor M7, as explained above.

[0115] [State of currents I1 and I2] Currents I1 and I2 are constant. Note that, in the relationship between the gate-source voltage VGS2 of PMOS transistor M2 and the gate-source voltage VGS3 of PMOS transistor M3, when the potential difference between voltage V1 and voltage V2 is less than the detection threshold Vth, the current I2 flowing through the drain of PMOS transistor M3 is slightly larger than the current I1 flowing through the drain of PMOS transistor M2.

[0116] [State of current I3] Since the NMOS transistor M7 is ON, a constant current I3 flows. Note that the voltage V6 is close to GND level, so when no overcurrent is detected (normal operation), an L level is output as the overcurrent detection signal s1, and the L level overcurrent detection signal s1 is sent to the logic circuit 21.

[0117] (Overcurrent detection period t2) [State of voltages V1 and V2] Voltage V1 is the power supply voltage VCC applied from the power supply terminal VT, so it does not change. On the other hand, when the output element M0 connected between the power supply terminal VT and the output terminal OUT is turned on, current flows through the output element M0, and as the current flowing through the output element M0 increases, voltage V2 drops further compared to period t1. Period t2 (the period during which an overcurrent is considered to be occurring) is the period during which the potential difference between voltages V1 and V2 is greater than or equal to the detection threshold Vth.

[0118] [State of voltage V3] Since it is the same as the state during period t1, voltage V3 is a constant voltage value determined by the on-resistance of the PMOS transistor M1. [State of voltage V4] Since it is the same as the state during period t1, voltage V4 is fixed as a constant gate voltage value that allows the NMOS transistor M5 to flow current I1.

[0119] [State of voltage V5] When the potential difference between voltage V1 and voltage V2 is greater than or equal to the detection threshold Vth, the voltage drop of V2 increases, and the potential difference between the power supply terminal VT and the output terminal OUT becomes greater than the potential difference between the gate-source voltages VGS2 and VGS3 of the PMOS transistors M2 and M3, which are determined as the detection threshold Vth.

[0120] In this case, a voltage V4 at the same level as during period t1 is applied to the gate of the NMOS transistor M6, so there is no change in the current-driving capability of the NMOS transistor M6.

[0121] On the other hand, as the voltage V2 drops, the gate-source voltage VGS3 of the PMOS transistor M3 decreases, so the current driving capability of the PMOS transistor M3 decreases compared to period t1 (as the current I2 flowing through the PMOS transistor M3 decreases due to the decrease in current driving capability). Therefore, when the current I2 falls below the current that the NMOS transistor M6 can supply, the voltage V5 across the drain of the PMOS transistor M3 decreases.

[0122] [State of voltage V6] As voltage V5 decreases, NMOS transistor M7 turns off. Since NMOS transistor M7 is off, voltage V6 increases due to current I3.

[0123] [State of currents I1 and I2] Current I1 remains constant, as with period t1. Current I2 decreases as the voltage V2 decreases. [State of current I3] Current I3 decreases when the NMOS transistor M7 is turned off. As the voltage V6 increases, when overcurrent is detected, an H level is output as the overcurrent detection signal s1, and the H level overcurrent detection signal s1 is sent to the logic circuit 21.

[0124] <IPS with overcurrent protection circuit and temperature compensation function> Figure 10 shows an example of the configuration of an IPS with an overcurrent protection circuit that has a temperature compensation function. The IPS with an overcurrent protection circuit 1-2 of the present invention is equipped with an overcurrent protection circuit 2 compared to the IPS with an overcurrent detection circuit 1-1 shown in Figure 4, and the other configurations are the same as in Figure 4. The overcurrent protection circuit 2 has an overcurrent detection circuit 2a and a temperature compensation circuit 10. The temperature compensation circuit 10 includes the temperature detection circuit 11 and correction circuit 12 shown in Figures 2 and 3.

[0125] Figure 11 shows an example of the configuration of an overcurrent protection circuit. Overcurrent protection circuit 2 is the overcurrent detection circuit 2a shown in Figure 5 with the addition of a temperature detection circuit 11 and a correction circuit 12. The constant current source IR1 in the overcurrent detection circuit 2a corresponds to the main current source Im shown in Figure 3. The constant current source IR1 can be configured with a depletion-type MOS transistor whose input terminal is the drain and whose output terminals are the gate, source, and back gate. In such a configuration, the constant current source IR1 tends to exhibit significant temperature dependence. Therefore, the main current source Im shown in Figure 3 corresponds to the constant current source IR1 in the overcurrent detection circuit 2a. Figure 12 shows a correction circuit 12-2 in which the main current source Im and correction current elements Ic1 to Ic4 shown in Figure 3 are configured with depletion-type MOS transistors.

[0126] Regarding the connection relationship between the correction circuit 12 and the overcurrent detection circuit 2a, the input terminal of the constant current source IR1 is connected to the input terminals of the correction current elements Ic1, ..., Ic4, the drain of PMOS transistor M1, the gate of PMOS transistor M1, the gate of PMOS transistor M2, the gate of PMOS transistor M3, and the gate of PMOS transistor M4.

[0127] The output terminal of the constant current source IR1 is connected to terminal b1 of switch sw1, terminal b2 of switch sw2, terminal b3 of switch sw3, terminal b4 of switch sw4, the source of NMOS transistor M5, the back gate of NMOS transistor M5, the source of NMOS transistor M6, the back gate of NMOS transistor M6, the source of NMOS transistor M7, the back gate of NMOS transistor M7, the ground terminal of the temperature detection circuit 11, and GND. Note that switches sw1, ..., sw4 can be made up of nMOS elements, for example.

[0128] Figure 13 shows a modified example of the overcurrent protection circuit. Overcurrent protection circuit 2-1a is a different circuit configuration of overcurrent protection circuit 2 shown in Figure 11. In overcurrent protection circuit 2 shown in Figure 11, a constant current source is located on the GND side. On the other hand, the overcurrent protection circuit shown in Figure 13 protection In circuit 2-1a, a constant current source is placed on the power supply side. Also, for switches sw1 to sw4, in the overcurrent protection circuit 2 shown in Figure 11, nMOS is used, and in the overcurrent protection circuit shown in Figure 13... protection In circuit 2-1a, a pMOS is assumed, so as the temperature rises based on the signal from the temperature detection circuit 11, the current increases as the level changes from H to L, causing the threshold to rise.

[0129] <Waveform during temperature compensation> Figure 14 shows an example of waveforms during temperature compensation. Graph g1 shows the gate voltages of PMOS transistors M2 and M3 (hereinafter referred to as differential pair gate voltages), with the vertical axis being voltage (V). Graph g2 shows the temperature detection signals A, B, C, and D, with the vertical axis being voltage (V). Graph g3 shows the current at the output terminal of the constant current source IR1, with the vertical axis being current (μA). The horizontal axis in graphs g1, g2, and g3 is temperature (°C).

[0130] [T < -25°C] When the temperature T is less than -25°C, the constant current source IR1 outputs a current I11, and the current I11 gradually decreases as the temperature rises. The differential pair gate voltage is voltage Vg1, and the voltage Vg1 gradually decreases as the temperature rises. Also, the temperature detection signals A, B, C, and D are at L level.

[0131] [-25°C≦T<40°C] When the temperature T is between -25°C and 40°C, temperature detection signal A becomes H level, and temperature detection signals B, C, and D become L level, so a correction current ic1 is output from the correction current element Ic1. Therefore, the current at the output terminal of the constant current source IR1 increases to current I12 with the addition of the correction current ic1. Note that current I12 also gradually decreases with increasing temperature. The differential pair gate voltage decreases from voltage Vg1 to Vg2 with increasing current, and voltage Vg2 also gradually decreases with increasing temperature.

[0132] [40°C ≤ T < 100°C] When the temperature T is between 40°C and 100°C, temperature detection signals A and B become H level, and temperature detection signals C and D become L level, so a correction current ic2 is output from the correction current element Ic2. Therefore, the current at the output terminal of the constant current source IR1 increases to current I13 with the addition of the correction current ic2. Note that current I13 also gradually decreases with increasing temperature. The differential pair gate voltage decreases from voltage Vg2 to Vg3 with increasing current, and voltage Vg3 also gradually decreases with increasing temperature.

[0133] [100°C ≤ T < 155°C] When the temperature T is between 100°C and 155°C, temperature detection signals A, B, and C become H level, and temperature detection signal D becomes L level, so a correction current ic3 is output from the correction current element Ic3. Therefore, the current at the output terminal of the constant current source IR1 increases to current I14 with the addition of the correction current ic3. Note that current I14 also gradually decreases with increasing temperature. The differential pair gate voltage decreases from voltage Vg3 to Vg4 with increasing current, and voltage Vg4 also gradually decreases with increasing temperature.

[0134] [155°C≦T] When the temperature T is 155°C or higher, the temperature detection signals A, B, C, and D become H level, and a correction current ic4 is output from the correction current element Ic4. Therefore, the current at the output terminal of the constant current source IR1 increases to current I15 due to the addition of the correction current ic4. Note that current I15 also gradually decreases with increasing temperature. The differential pair gate voltage decreases from voltage Vg4 to Vg5 with increasing current, and voltage Vg5 also gradually decreases with increasing temperature.

[0135] <Temperature dependence of overcurrent detection threshold> Figure 15 illustrates the temperature dependence of the overcurrent detection threshold. The vertical axis represents the drain current IDS(A), and the horizontal axis represents the gate-source voltage VGS(V). The drain current of PMOS transistor M2 is denoted as drain current IM2, and the drain current of PMOS transistor M3 is denoted as drain current IM3.

[0136] The drain current IM2 represents the VGS-IDS characteristic of PMOS transistor M2, and the drain current IM3 represents the VGS-IDS characteristic of PMOS transistor M3. Furthermore, the potential difference between the VGS of PMOS transistor M2 and the VGS of PMOS transistor M3 at the same current value for drain currents IM2 and IM3 is the detection threshold.

[0137] [T=25°C] When the temperature T is 25°C, the current at the output terminal of the constant current source IR1 is current I20, and the potential difference of the detection threshold at this time is Vth1. When the temperature T rises to 175°C (〔T = 175°C〕), the current at the output terminal of the constant current source IR1 decreases from the current I20 to the current I21. The potential difference of the detection threshold at this time is Vth2, and Vth2 < Vth1, so the detection threshold decreases as the temperature rises. Thus, due to the decrease in the current value of the constant current source IR1 with the increase in temperature, the detection threshold at a temperature of 25°C decreases due to the temperature increase to 175°C.

[0138] <Suppression of Variation in Detection Threshold by Temperature Compensation> FIG. 16 is a diagram for explaining the suppression of variation in the detection threshold by temperature compensation. The vertical axis represents the drain current IDS (A), and the horizontal axis represents the gate-source voltage VGS (V).

[0139] When the temperature T is 25°C (〔T = 25°C〕), the current at the output terminal of the constant current source IR1 is the current I20, and the potential difference of the detection threshold at this time is Vth1. When the temperature T rises to 175°C (〔T = 175°C〕), the current at the output terminal of the constant current source IR1 is corrected by the correction current source 12a. Therefore, it becomes the current I20a near the current I20. The potential difference of the detection threshold at this time is Vth1a, and Vth1a ≒ Vth1, so the decrease in the detection threshold with the increase in temperature is suppressed.

[0140] Thus, in the IPS1-2 with an overcurrent protection circuit, the current at the output terminal of the constant current source IR1 is increased with the increase in temperature by the correction current from the correction current source 12a output based on the temperature detection signal by the temperature detection circuit 11. Thereby, even when the temperature rises from 25°C to 175°C, the decrease in the detection threshold at a temperature of 25°C can be suppressed.

[0141] <Inverter Device> Next, as an application example of the temperature compensation function of the semiconductor device 1, an inverter device will be described. FIG. 17 is a diagram showing an example of the configuration of the inverter device. The inverter device 3 includes a PMOS transistor M10, a constant current source IR3, a temperature detection circuit 11, and a correction circuit 12.

[0142] In the inverter device 3, a temperature detection circuit 11 and a correction circuit 12 are connected to an inverter circuit consisting of a PMOS transistor M10 and a constant current source IR3. The constant current source IR3 corresponds to the main current source Im shown in Figure 3.

[0143] In terms of the connections between the constituent elements, the input terminal IN is connected to the gate of the PMOS transistor M10. The power supply terminal VT is connected to the source of the PMOS transistor M10, the back gate of the PMOS transistor M10, and the power supply terminal of the temperature detection circuit 11.

[0144] The input terminal of the constant current source IR3 is connected to the input terminals of the correction current elements Ic1, ..., Ic4, the drain and output terminal OUT of the PMOS transistor M10. The output terminal of the constant current source IR3 is connected to terminal b1 of switch sw1, terminal b2 of switch sw2, terminal b3 of switch sw3, terminal b4 of switch sw4, the ground terminal of the temperature detection circuit 11 and GND. Note that switches sw1, ..., sw4 can be made up of nMOS elements, for example.

[0145] In the configuration described above, current correction is performed at the output terminal of the constant current source IR3, making it possible to adjust the threshold voltage of the inverter circuit consisting of the PMOS transistor M10 and the constant current source IR3 to a desired value.

[0146] Figure 18 shows a modified example of the inverter device. Inverter device 3-1 is a different circuit configuration of inverter device 3 shown in Figure 17. In inverter device 3 shown in Figure 17, the constant current source is located on the GND side, but in inverter device 3-1 shown in Figure 18, the constant current source is located on the power supply side. Note that switches sw1, ..., sw4 can be made of, for example, pMOS elements.

[0147] <Example of an overcurrent protection circuit> Figure 19 shows a modified example of the overcurrent protection circuit. The overcurrent protection circuit 2-1 is the overcurrent detection circuit 2a shown in Figure 5 with the addition of a temperature detection circuit 11 and a correction circuit 12-1. The correction circuit 12-1 includes a current mirror ratio correction circuit 12a1 and a switch circuit 12b, and the current mirror ratio correction circuit 12a1 includes PMOS transistors M11, ..., M14 as correction elements.

[0148] Note that PMOS transistors M11, ..., M14 correspond to the first to fourth corrective PMOS transistors, respectively. Also, the PMOS transistor M1 is the target of correction in the overcurrent protection circuit 2-1.

[0149] Regarding the connections within the correction circuit 12-1 and the connections to PMOS transistor M1, the source of PMOS transistor M1 is connected to the power supply terminal VT, the back gate of PMOS transistor M1, the source of PMOS transistor M2, the back gate of PMOS transistor M2, the back gate of PMOS transistor M3, the source of PMOS transistor M4, and the back gate of PMOS transistor M4.

[0150] Furthermore, the source of PMOS transistor M1 is connected to terminal b1 of switch sw1, terminal b2 of switch sw2, terminal b3 of switch sw3, and terminal b4 of switch sw4. In addition, the source of PMOS transistor M1 is connected to the back gate of PMOS transistor M11, the back gate of PMOS transistor M12, the back gate of PMOS transistor M13, and the back gate of PMOS transistor M14.

[0151] On the other hand, the source of PMOS transistor M11 is connected to terminal a1 of switch sw1, and the source of PMOS transistor M12 is connected to terminal a2 of switch sw2. The source of PMOS transistor M13 is connected to terminal a3 of switch sw3, and the source of PMOS transistor M14 is connected to terminal a4 of switch sw4.

[0152] Furthermore, the drain of PMOS transistor M1 is connected to the gate of PMOS transistor M1, the input terminal of constant current source IR1, the gate of PMOS transistor M2, the gate of PMOS transistor M3, and the gate of PMOS transistor M4.

[0153] Furthermore, the drain of PMOS transistor M1 is connected to the drains of PMOS transistor M11, PMOS transistor M12, PMOS transistor M13, and PMOS transistor M14.

[0154] Furthermore, the drain of PMOS transistor M1 is connected to the gates of PMOS transistor M11, PMOS transistor M12, PMOS transistor M13, and PMOS transistor M14.

[0155] In the configuration described above, the Miller ratio of the PMOS transistor M1 can be adjusted by the temperature detection circuit 11 and the correction circuit 12-1. Here, since the PMOS transistor M1 forms a current mirror with respect to the PMOS transistors M2 and M3, the current flowing through the PMOS transistors M1 and M11~M14 can be adjusted by the correction circuit 12-1, thereby also adjusting the current flowing through the PMOS transistors M2 and M3.

[0156] Therefore, for example, if the number of switches that turn on decreases as the temperature rises, the current through PMOS transistors M2 and M3 can be increased, thereby suppressing a decrease in the detection threshold. When the temperature detection signal is at a high level, switches sw1, ..., sw4 are on, PMOS transistors M11, ..., M14 are off, and a constant current is supplied to PMOS transistor M1. source The gate voltage VGS required to pass IR1 is increased, which is adjusted to increase the currents of M2 and M3.

[0157] Figure 20 shows a modified example of the overcurrent protection circuit. Overcurrent protection circuit 2-1b is a different circuit configuration of overcurrent protection circuit 2-1 shown in Figure 19. In overcurrent protection circuit 2-1 shown in Figure 19, a constant current source is located on the GND side. On the other hand, the overcurrent protection circuit shown in Figure 20 protection In circuit 2-1b, a constant current source is placed on the power supply side. Also, switches sw1 to sw4 are nMOS in the overcurrent protection circuit 2-1 shown in Figure 19, and overcurrent protection shown in Figure 20. protection Circuit 2-1b assumes a pMOS transistor. In both cases, the signal from the temperature detection circuit 11 reduces the number of ON elements in switches sw1 to sw4, thereby increasing the current in the differential pair.

[0158] As described above, the present invention provides a configuration in which the temperature of a temperature-dependent semiconductor element is detected, a temperature detection signal corresponding to the detected temperature is generated, and the characteristics of the semiconductor element are corrected based on the temperature detection signal.

[0159] This allows for temperature detection and correction of semiconductor element characteristics, thereby improving the operational accuracy of devices equipped with temperature-dependent semiconductor elements, even in the event of temperature changes.

[0160] Furthermore, as described above, according to the present invention, temperature compensation control is performed based on a digital temperature detection signal that divides the temperature into n steps. Therefore, the number of components in the temperature detection circuit 11 and the correction circuit 12 can be increased or decreased according to the number of temperature divisions n, making it possible to easily increase the degree of design flexibility according to the ambient temperature.

[0161] Although embodiments have been illustrated above, the configurations of each part shown in the embodiments can be replaced with others having similar functions. Furthermore, other arbitrary components or processes may be added. Moreover, any two or more configurations (features) from the embodiments described above may be combined. [Explanation of symbols]

[0162] 1 Semiconductor device 1a Semiconductor device 11. Temperature detection circuit 12 Correction Circuit Ta, Tb, Tc, Td Temperature d1, d2, d3 Temperature detection signals Ia1, Ia2, Ia3, Ia4 current ic1, ic2, ic3 Correction current

Claims

1. A semiconductor element having temperature dependence, characterized in that the output current changes with temperature changes, A temperature detection circuit that detects temperature and outputs a temperature detection signal corresponding to the detected temperature, The device includes a correction circuit that corrects the characteristics of the semiconductor element based on the temperature detection signal, The temperature detection circuit is A constant current source for temperature detection, A detection circuit including a temperature sense diode whose temperature detection voltage, based on the current from the constant current source for temperature detection, decreases as the temperature rises, A reference voltage generating unit that generates a reference voltage based on the current from the constant current source for temperature detection, The circuit includes a comparison circuit that compares the reference voltage with the temperature detection voltage and outputs a temperature detection signal at a predetermined level if the reference voltage is higher than the temperature detection voltage. The constant current source for temperature detection includes a first constant current source and a second constant current source. The reference voltage generation unit includes a total of n resistors connected in series from the first resistor to the nth (where n is a natural number), in order from the high potential side to the low potential side, and the comparison circuit includes a total of n comparators from the first comparator to the nth comparator. The input terminal of the first constant current source is connected to the input terminal of the second constant current source and the power supply unit. The output terminal of the first constant current source is connected to the anode of the temperature sense diode and to the inverting input terminals of a total of n comparators, from the first comparator to the nth comparator. The output terminal of the second constant current source is connected to the non-inverting input terminal of the first comparator and one end of the first resistor, and a first temperature detection signal of a predetermined level is output from the output terminal of the first comparator. The non-inverting input terminal of the k-th comparator is directly connected to the high-potential terminal of the k-th resistor, and a temperature detection signal of the k-th resistor at a predetermined level is output from the output terminal of the k-th comparator according to the set temperature (1 ≤ k ≤ n). The other end of the aforementioned resistor n is connected to the cathode and ground of the temperature sense diode. Semiconductor equipment.

2. The semiconductor device according to claim 1, wherein the temperature detection circuit outputs the first to the nth temperature detection signals for each of the n temperature stages (where n is a natural number), and the correction circuit outputs a correction current that corrects the current change for each temperature based on the n temperature detection signals.

3. The reference voltage generation unit generates n reference voltages, the voltage values ​​of which decrease from the 1st to the nth, based on the current from the constant current source for temperature detection. The comparison circuit compares the k-th (1 ≤ k ≤ n) reference voltage out of n with the temperature detection voltage, and outputs the temperature detection signal at a predetermined level for the k-th or lower if the k-th reference voltage is higher than the temperature detection voltage. The semiconductor device according to claim 2.

4. The correction circuit described above is A correction element circuit including a correction element that outputs the correction current, A switch circuit including a switch that switches the input or output of the correction element based on the temperature detection signal at a predetermined level, A semiconductor device according to claim 3, having the following features.

5. The correction element circuit includes the first to the nth correction elements, The switch circuit includes the first to the nth switches that switch the input or output of the correction element, respectively. When a temperature detection signal of a predetermined level k (1 ≤ k ≤ n) or lower is output, the k-th or lower switches are turned on, and the k-th or lower correction elements output the correction current. The semiconductor device according to claim 4.

6. The correction element circuit includes a total of n correction elements from the first correction element to the nth correction element, and the switch circuit includes a total of n switches from the first switch to the nth switch. The total of n correction elements, from the first correction element to the nth correction element, are each connected in parallel to the semiconductor element. The n switches, from the first switch to the nth switch, are each connected in parallel to the semiconductor element. The k-th switch is connected in series with the k-th correction element. The semiconductor device according to claim 5.

7. The aforementioned semiconductor device is Overcurrent detection in a current path is performed when the potential difference between two points, the first terminal and the second terminal of the current path, exceeds a detection threshold. Characterized by being a component of an overcurrent detection circuit, The semiconductor device according to claim 6.

8. The overcurrent detection circuit comprises a detection unit, a potential generation unit, and an output unit. The detection unit comprises a differential pair element whose first high-potential end is connected to the first terminal and whose second high-potential end is connected to the second terminal, and a current mirror circuit connected to the low-potential side of the differential pair element. The potential generation unit outputs the generated potential to the control terminal of the differential pair element of the detection unit. The output unit is connected to the low-potential side of the element on which the second high-potential end of the differential pair element is connected to the second terminal, and outputs an overcurrent detection signal representing the overcurrent detection result. The semiconductor element is characterized in that it is a component of the potential generation unit. The semiconductor device according to claim 7.

9. The potential generation unit comprises a first PMOS transistor and a constant current source. The source of the first PMOS transistor is connected to the back gate and power supply terminals of the first PMOS transistor. The drain of the first PMOS transistor is connected to the input terminal of the constant current source, the gate of the first PMOS transistor, and the output terminal of the potential generation unit. The output terminal of the constant current source is connected to ground. The differential pair element of the detection unit comprises a second PMOS transistor and a third PMOS transistor. The control terminals of the differential pair are connected to the gate of the second PMOS transistor, the gate of the third PMOS transistor, and the output terminal of the potential generation unit. The source of the second PMOS transistor is connected to the first terminal via the first high-potential terminal. The source of the third PMOS transistor is connected to the second terminal via the second high-potential terminal. The back gates of the second PMOS transistor and the third PMOS transistor are connected to the power supply terminals. The current mirror circuit of the detection unit comprises a first NMOS transistor and a second NMOS transistor. The drain of the first NMOS transistor is connected to the gate of the first NMOS transistor, the gate of the second NMOS transistor, and the drain of the second PMOS transistor. The drain of the second NMOS transistor is connected to the drain of the third PMOS transistor. The source and back gate of the first NMOS transistor and the source and back gate of the second NMOS transistor are connected to ground. The semiconductor device according to claim 8.

10. The correction element circuit is a correction current source and includes a total of n correction current elements, from the first correction current element to the nth correction current element, and the switch circuit includes a total of n switches, from the first switch to the nth switch. The input terminals of the total of n correction current elements, from the first correction current element to the nth correction current element, are connected to the input terminals of the constant current source, which is a semiconductor element. The output terminal of the k-th correction current element is connected to the first terminal of the k-th switch. The second terminals of the n switches, from the first switch to the nth switch, are connected to the output terminal and ground of the constant current source. The control terminal of the switch k is connected to the output terminal of the comparator k. The semiconductor device according to claim 9.

11. The correction element circuit is a current mirror ratio correction circuit, and the correction element includes a total of n correction PMOS transistors from the first correction PMOS transistor to the nth correction PMOS transistor, and the switch circuit includes a total of n switches from the first switch to the nth switch. The drains and gates of the total of n transistors from the first correction PMOS transistor to the nth correction PMOS transistor are connected to the drain of the first PMOS transistor, which is a semiconductor element. The source of the k-th correction PMOS transistor is connected to the first terminal of the k-th switch. The back gate of the correction PMOS transistor k is connected to the power supply. The control terminal of the switch k is connected to the output terminal of the comparator k. The semiconductor device according to claim 9.

12. The potential generation unit comprises a first NMOS transistor and a constant current source. The source of the first NMOS transistor is connected to the back gate and ground of the first NMOS transistor. The drain of the first NMOS transistor is connected to the output terminal of the constant current source, the gate of the first NMOS transistor, and the output terminal of the potential generation unit. The differential pair element of the detection unit comprises a first PMOS transistor and a second PMOS transistor. The gate of the first PMOS transistor is connected to the drain of the first PMOS transistor and the gate of the second PMOS transistor. The source of the first PMOS transistor is connected to the first terminal via the first high-potential terminal. The source of the second PMOS transistor is connected to the second terminal via the second high-potential terminal. The back gates of the first PMOS transistor and the second PMOS transistor are connected to a power supply. The current mirror circuit of the detection unit comprises a second NMOS transistor and a third NMOS transistor. The control terminal of the current mirror circuit is connected to the gate of the second NMOS transistor, the gate of the third NMOS transistor, the drain of the first PMOS transistor, and the potential generation unit. The drain of the second NMOS transistor is connected to the drain of the first PMOS transistor. The drain of the third NMOS transistor is connected to the drain of the second PMOS transistor. The source and back gate of the second NMOS transistor and the source and back gate of the third NMOS transistor are connected to ground. The semiconductor device according to claim 8.

13. The correction element circuit is a correction current source and includes a total of n correction current elements, from the first correction current element to the nth correction current element, and the switch circuit includes a total of n switches, from the first switch to the nth switch. The output terminals of the total of n correction current elements, from the first correction current element to the nth correction current element, are connected to the output terminals of the constant current source, which is a semiconductor element. The input terminal of the k-th correction current element is connected to the first terminal of the k-th switch, The second terminals of the n switches, from the first switch to the nth switch, are connected to the input terminals of the constant current source. The control terminal of the switch k is connected to the output terminal of the comparator k. The semiconductor device according to claim 12.

14. The correction element circuit is a current mirror ratio correction circuit, and the correction element includes a total of n correction NMOS transistors from the first correction NMOS transistor to the nth correction NMOS transistor, and the switch circuit includes a total of n switches from the first switch to the nth switch. The drains and gates of the total of n transistors from the first correction NMOS transistor to the nth correction NMOS transistor are connected to the drain of the first NMOS transistor, which is a semiconductor element. The source of the k-th correction NMOS transistor is connected to the first terminal of the k-th switch. The back gate of the correction NMOS transistor k is connected to the second terminal of the switch k and the source of the first NMOS transistor. The control terminal of the switch k is connected to the output terminal of the comparator k. The semiconductor device according to claim 12.

15. A semiconductor device according to any one of claims 10 to 14, An output element that is connected to the power supply voltage via the first terminal and to the load via the second terminal, and switches based on the drive signal to operate the load, An overcurrent detection circuit having a semiconductor element, wherein the potential difference between the power supply voltage, the on-resistance of the output element, and the current flowing through the output element, and the output voltage applied to the load from the second terminal, is used as the overcurrent detection threshold for detecting an overcurrent, The temperature detection circuit and, The correction circuit and, A temperature compensation circuit including, An IPS with temperature-dependent compensation function.

16. Having the functionality of the semiconductor device described in claim 6, An output element that switches based on a drive signal, A constant current source, which is a semiconductor element, is connected in series with the output element. The temperature detection circuit and, The correction circuit and, An inverter device having the following features.

17. The correction element circuit is a correction current source and includes a total of n correction current elements, from the first correction current element to the nth correction current element, and the switch circuit includes a total of n switches, from the first switch to the nth switch. The input terminals of the total of n correction current elements, from the first correction current element to the nth correction current element, are connected to the input terminals of the constant current source, which is a semiconductor element. The output terminal of the k-th correction current element is connected to the first terminal of the k-th switch. The second terminals of the n switches, from the first switch to the nth switch, are connected to the output terminal and ground of the constant current source. The control terminal of the switch k is connected to the output terminal of the comparator k. The inverter device according to claim 16.

18. The correction element circuit is a correction current source and includes a total of n correction current elements, from the first correction current element to the nth correction current element, and the switch circuit includes a total of n switches, from the first switch to the nth switch. The output terminals of the total of n correction current elements, from the first correction current element to the nth correction current element, are connected to the output terminals of the constant current source, which is a semiconductor element. The input terminal of the k-th correction current element is connected to the first terminal of the k-th switch, The second terminals of the n switches, from the first switch to the nth switch, are connected to the input terminals of the constant current source. The control terminal of the switch k is connected to the output terminal of the comparator k. The inverter device according to claim 16.

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