Driving device

Abstract

To generate various drive currents.SOLUTION: A driving device includes: a drive control part for controlling a drive current of a power semiconductor based on a load current or an element temperature of the power semiconductor and a driver circuit for supplying the drive current to the power semiconductor. The driver circuit includes: a reference part for generating a reference current; two or more mirror circuits provided mutually in parallel, for respectively generating a mirror current according to the reference current; and a current generation part for generating the drive current based on a current flowing through the two or more mirror circuits. The drive control part controls the drive current by controlling whether or not to cause the current generation part to output the mirror current for one or more of the mirror circuits.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drive device. [Background technology]

[0002] Conventionally, circuits that generate a drive current for driving a target device such as a power semiconductor are known (see, for example, Patent Documents 1 to 3). Patent Document 1: JP 2019-110677 A Patent Document 2 Patent No. 5063124 Patent Document 3: JP 2019-176392 A Summary of the Invention [Problem to be solved by the invention]

[0003] It is preferable to be able to generate a wide variety of drive currents. [Means for solving the problem]

[0004] In order to solve the above problem, in one aspect of the present invention, a driving device for a power semiconductor is provided. The driving device may include at least one of a current detection unit that detects the magnitude of a load current supplied from the power semiconductor to a load, or a temperature detection unit that detects an element temperature of the power semiconductor. Any of the driving devices may include a drive control unit that controls a driving current of the power semiconductor based on at least one of the load current or the element temperature. Any of the driving devices may include a driver circuit that supplies the driving current to the power semiconductor. In any of the driving devices, the driver circuit may include a reference unit that generates a reference current. In any of the driving devices, the driver circuit may include two or more mirror circuits that are provided in parallel with each other and each generate a mirror current corresponding to the reference current. In any of the driving devices, the driver circuit may include a current generation unit that generates the driving current based on a current flowing through the two or more mirror circuits. In any of the driving devices described above, the driving control section may control the driving current by controlling whether or not one or more of the mirror circuits are caused to output the mirror current to the current generating section.

[0005] In any of the driving devices described above, the driving control section may control the magnitude of the reference current to control the driving current.

[0006] In any of the driving devices described above, the ratio of the mirror current to the reference current may be different in at least two of the mirror circuits.

[0007] Any of the above drive devices may include a control memory that records the drive current to be set for each of a plurality of detection states including at least one of the load current and the element temperature. In any of the above drive devices, the drive control unit may read out a setting record signal indicating the drive current from the control memory based on the detection state corresponding to at least one of the detected values ​​of the load current and the element temperature.

[0008] In any of the drive devices described above, the drive control section may change the drive current every time the load current exceeds one or more preset current threshold values.

[0009] When the power semiconductor is turned on, the voltage between the main terminals of the power semiconductor may change with a first slope with respect to time. A current-slope characteristic, which is a characteristic of the first slope with respect to the load current, may have a first linear region in which the first slope changes linearly with respect to the load current, and a first nonlinear region in which the first slope changes nonlinearly with respect to the load current in a region where the load current is smaller than the first linear region. In any of the above drive devices, at least one of the current thresholds may be set in the first nonlinear region.

[0010] In any of the driving devices described above, the drive control unit may change the drive current every time the element temperature exceeds one or more preset temperature threshold values.

[0011] The temperature-loss characteristic, which is a characteristic of the turn-on loss of the power semiconductor with respect to the element temperature, may have a second linear region in which the turn-on loss changes linearly with respect to the element temperature, and a second nonlinear region in which the turn-on loss changes nonlinearly with respect to the element temperature in a region where the element temperature is higher than the second linear region. In any of the driving devices described above, at least one of the temperature thresholds may be set in the second nonlinear region.

[0012] When the power semiconductor is turned on, a voltage between main terminals of the power semiconductor may change with respect to time with a first gradient. An operating temperature range may be set for the power semiconductor. In any of the drive devices described above, the drive control unit may control the drive current so that the first gradient when the drive current is increased is equal to or smaller than the first gradient when the element temperature is at a lower limit of the operating temperature range and the drive current is at a minimum value.

[0013] In any one of the driving devices, three or more temperature thresholds may be set. In any one of the driving devices, the difference between adjacent temperature thresholds may be smaller as the temperature thresholds are higher.

[0014] When the power semiconductor is turned on, the voltage between the main terminals of the power semiconductor may change with a first slope with respect to time. A temperature-slope characteristic which is a characteristic of the first slope with respect to the element temperature may have a third linear region in which the first slope changes linearly with respect to the element temperature, and a third nonlinear region in which the first slope changes nonlinearly with respect to the element temperature in a region where the element temperature is higher than the third linear region. In any of the above driving devices, a difference between adjacent temperature thresholds in the third nonlinear region may be smaller than a difference between adjacent temperature thresholds in the third linear region.

[0015] In a second aspect of the present invention, there is provided a driving device for a power semiconductor. The driving device may include a current detection unit that detects the magnitude of a load current supplied from the power semiconductor to a load. The driving device may include a temperature detection unit that detects an element temperature of the power semiconductor. The driving device may include a driving control unit that controls a driving current of the power semiconductor based on the load current and the element temperature. The driving device may include a control memory that records the driving current to be set for each of a plurality of combinations of the load current value and the element temperature value. In any of the driving devices, the driving control unit may read out from the control memory a setting record signal indicating the driving current corresponding to the combination of the detected load current value and the element temperature value.

[0016] The above summary of the invention does not list all of the features of the present invention. In addition, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram illustrating an example of a power supply device 300 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a driver circuit 128. [Diagram 3] 10 is a diagram illustrating an example of the operation of the encoder 122. FIG. [Figure 4] 10 is a diagram illustrating an example of the operation of a selection unit 124. FIG. [Diagram 5] 4 is a diagram showing an example of information stored in the control memory 106. FIG. [Figure 6] 3A to 3C are diagrams illustrating an example of the operation of the driving device 100. [Figure 7] 3A to 3C are diagrams illustrating an example of the operation of the driving device 100. [Figure 8] FIG. 13 is a diagram showing an example of current-slope characteristics. [Figure 9] FIG. 13 is a diagram showing an example of temperature-loss characteristics. [Figure 10] FIG. 13 is a diagram showing an example of temperature-gradient characteristics. [Figure 11] 1 is a diagram showing an example of the time waveforms of the load current Ic and the voltage Vce between the main terminals when the power semiconductor 202 is turned on. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention will be described below through the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown. In addition, in one drawing, elements having the same functions and configurations may be given the same reference numerals as representative elements, and the reference numerals may be omitted for the others.

[0019] In this specification, when the term "same" or "equal" is used, it may include cases where there is an error due to manufacturing variations, etc. The error is, for example, within 10%.

[0020] 1 is a diagram showing an example of a power supply device 300 according to an embodiment of the present invention. The power supply device 300 supplies power to a load. The load is, for example, but not limited to, a circuit provided in a vehicle or an industrial robot. The power supply device 300 includes a drive device 100 and an output device 200.

[0021] The output device 200 supplies power to a load. The output device 200 includes a power semiconductor 202. The power semiconductor 202 is, for example, an IGBT, but may be a MOSFET or other device. The power semiconductor 202 in this example is an IGBT with a collector terminal C connected to a load. When the power semiconductor 202 is a lower arm circuit, the collector terminal C of the power semiconductor 202 may be connected to a power semiconductor in an upper arm.

[0022] The output device 200 of this example further includes a current extraction power semiconductor 204 and a temperature sensor 206. The current extraction power semiconductor 204 extracts a current value for detecting the current flowing through the power semiconductor 202 by the current detection unit 108. The current extraction power semiconductor 204 of this example is a semiconductor element electrically connected in parallel with the power semiconductor 202. The current extraction power semiconductor 204 may be a semiconductor element having a similar structure to the power semiconductor 202. Both the power semiconductor 202 and the current extraction power semiconductor 204 may be IGBTs or MOSFETs.

[0023] In the present example, the power semiconductor 202 and the current extraction power semiconductor 204 have collector terminals C connected to each other and gate terminals G connected to each other. The current extraction power semiconductor 204 may be provided on the same semiconductor substrate as the power semiconductor 202. The area of ​​the semiconductor substrate occupied by the current extraction power semiconductor 204 is smaller than the area occupied by the power semiconductor 202. The ratio of currents flowing through the power semiconductor 202 and the current extraction power semiconductor 204 is determined according to the ratio of the areas. The current flowing through the current extraction power semiconductor 204 may be 0.01 times or less, or may be 0.001 times or less, of the current flowing through the power semiconductor 202. By detecting the magnitude of the current flowing through the sense emitter terminal SE of the current extraction power semiconductor 204, the magnitude of the load current flowing from the emitter terminal E of the power semiconductor 202 to the load can be detected.

[0024] The temperature sensor 206 detects the element temperature of the power semiconductor 202. The element temperature is, for example, the temperature at any point of the power semiconductor 202. As an example, the temperature sensor 206 is provided above the semiconductor substrate of the power semiconductor 202. The temperature sensor 206 may be disposed on the upper surface of the semiconductor substrate via an insulating film. In this example, the temperature sensor 206 is a PN junction diode provided above the semiconductor substrate of the power semiconductor 202. The temperature sensor 206 may be formed of polysilicon. The electrical characteristics of the PN junction diode, such as the forward voltage, change depending on the temperature of the PN junction diode. By detecting the electrical characteristics of the temperature sensor 206, the element temperature of the power semiconductor 202 can be detected.

[0025] The driving device 100 drives a power semiconductor 202. The driving device 100 of this example controls the switching operation of the power semiconductor 202. The driving device 100 includes a current detection unit 108, a temperature detection unit 110, a driving control unit 120, and a driver circuit 128. The driving device 100 may include at least one of the current detection unit 108 or the temperature detection unit 110. A cooling driving device 100 includes both the current detection unit 108 and the temperature detection unit 110. The driving device 100 may further include at least one of a control memory 106, a power supply unit 102, and an input unit 104.

[0026] A power supply voltage VCC is applied to the power supply unit 102 from a power supply connected to the driving device 100. The power supply unit 102 generates an internal voltage VDD based on the power supply voltage VCC. Either the power supply voltage VCC or the internal voltage VDD may be applied to each component of the driving device 100 as a power supply voltage.

[0027] The input unit 104 receives an input signal IN from a control circuit connected to the drive device 100. The input signal IN in this example is a signal that controls the timing of switching the power semiconductor 202. For example, the input signal IN is a signal that has a first voltage level during a period when the power semiconductor 202 should be in an ON state, and a second voltage level during a period when the power semiconductor 202 should be in an OFF state. For example, the first voltage level is either an H level or an L level, and the second voltage level is the other of the H level and the L level. The input unit 104 generates an internal signal OUTOFF based on the input signal IN. The internal signal OUTOFF may have the same waveform pattern as the input signal IN. The internal signal OUTOFF may have a different amplitude from the input signal IN. As an example, the internal signal OUTOFF has an amplitude according to the internal voltage VDD.

[0028] The driver circuit 128 controls the switching operation of the power semiconductor 202 based on the internal signal OUTOFF. The driver circuit 128 of this example generates a control signal OUT based on the internal signal OUTOFF. The control signal OUT may have a waveform pattern similar to that of the internal signal OUTOFF. The control signal OUT may have an amplitude different from that of the internal signal OUTOFF. As an example, the control signal OUT has an amplitude according to the power supply voltage VCC of the power semiconductor 202 and the reference voltage PGND of the power semiconductor 202.

[0029] The driver circuit 128 supplies a drive current corresponding to the control signal OUT to the power semiconductor 202. The drive current is a current for changing the switching state of the power semiconductor 202. In this example, the drive current is a current for charging and discharging the gate capacitance of the power semiconductor 202. Depending on the amount of charge stored in the gate capacitance of the power semiconductor 202, the power semiconductor 202 is turned on or off.

[0030] The current detection unit 108 detects the magnitude of the load current supplied from the power semiconductor 202 to the load. The current detection unit 108 may receive a current signal OC indicating the magnitude of the load current from the output device 200. The current signal OC in this example is a signal indicating the magnitude of a sense current flowing through the sense emitter terminal SE of the current extraction power semiconductor 204. The current signal OC may be the sense current itself, or may be a signal obtained by converting the magnitude of the sense current into a voltage value.

[0031] The current detection unit 108 may output a current detection signal ILOW indicating the state of the load current. For example, the current detection signal ILOW is a signal indicating a result of comparing the load current with a predetermined current threshold. The current detection unit 108 may have one or more current thresholds. The possible range of the load current is divided into a plurality of current ranges by one or more current thresholds. The current detection signal ILOW may be a signal indicating which current range the load current belongs to. The current detection signal ILOW in this example indicates whether the load current belongs to a first current range I1 having a relatively small current value, or a second current range I2 having a current value larger than the first current range I1.

[0032] The current detection unit 108 may switch whether or not to detect the load current, based on the internal signal OUTOFF output by the input unit 104. For example, the current detection unit 108 may detect the load current during a period in which the power semiconductor 202 should be controlled to be in the on state, based on the internal signal OUTOFF.

[0033] The temperature detection unit 110 detects the element temperature of the power semiconductor 202. The temperature detection unit 110 may receive a temperature signal OT indicating the element temperature from the output device 200. The temperature signal OT in this example is a signal indicating the magnitude of the forward voltage of a PN junction diode included in the temperature sensor 206. The temperature signal OT may be the anode voltage of the PN junction diode.

[0034] The temperature detection unit 110 may output a temperature detection signal TL / TM / TH indicating the state of the element temperature. For example, the temperature detection signal TL / TM / TH is a signal indicating the result of comparing the element temperature with a predetermined temperature threshold. The temperature threshold in the temperature detection unit 110 may be one or more. The possible range of the element temperature is divided into a plurality of temperature ranges by one or more temperature thresholds. The temperature detection signal TL / TM / TH may be a signal indicating which temperature range the element temperature belongs to. In this example, the temperature detection signal TL / TM / TH indicates whether the element temperature belongs to a first temperature range TL having a relatively low temperature, a second temperature range TM having a higher temperature than the first temperature range TL, or a third temperature range TH having a higher temperature than the second temperature range TM.

[0035] The drive control unit 120 controls the magnitude of the drive current that the driver circuit 128 supplies to the power semiconductor 202 based on the load current and the element temperature. By controlling the magnitude of the drive current, the switching speed of the power semiconductor 202 can be controlled. For example, when the drive current is increased, the gate capacitance of the power semiconductor 202 is charged and discharged at a higher speed, and the switching speed becomes faster. The drive control unit 120 may control the magnitude of the drive current when the power semiconductor 202 is turned on. In this case, the speed at which the power semiconductor 202 is turned on can be controlled.

[0036] As the element temperature increases, the current flowing through the gate capacitance of the power semiconductor 202 tends to decrease. When the current flowing through the gate capacitance decreases, the switching period such as the turn-on period becomes longer, and switching losses such as turn-on loss Eon increase. The drive control unit 120 may control the driver circuit 128 so that the drive current increases as the element temperature increases. This makes it possible to suppress an increase in turn-on loss Eon.

[0037] When the load current increases or decreases, the switching noise and switching loss in the power semiconductor 202 also increase or decrease. For example, in a region where the load current is relatively small, the slope of the voltage waveform when the power semiconductor 202 is turned on becomes large, and the switching noise increases. Furthermore, when the load current increases, the switching loss in the power semiconductor 202 increases. The drive control unit 120 may reduce the drive current in a low current region where the load current is small, and may increase the drive current in a high current region where the load current is large. This makes it possible to reduce the switching loss in the high current region while suppressing the switching noise in the low current region.

[0038] The drive control unit 120 controls the drive current according to the detection result including at least one of the load current and the element temperature. The detection result may be at least one of the load current detected by the current detection unit 108 and the element temperature detected by the temperature detection unit 110, or may be a combination of the load current value and the element temperature value. The drive control unit 120 of this example controls the drive current according to a combination of the load current value and the element temperature value.

[0039] The control memory 106 records the magnitude of the drive current to be set for each of a plurality of detection states including at least one of the load current and the element temperature. The detection state may be at least one of the load current and the element temperature, or may be a combination of the load current and the element temperature. In this example, a case where the detection state is a combination of the load current and the element temperature will be described, but the drive control unit 120 can operate in the same way even when the detection state is the load current or the element temperature.

[0040] The detection state may be set in advance by a user or the like. The control memory 106 in this example records the magnitude of the drive current to be set for the detection state including both the value of the load current and the value of the element temperature. The control memory 106 may be rewritable in correspondence between the detection state and the magnitude of the load current. The correspondence may be set by a user of the power supply device 300 or the like based on the characteristics of the power semiconductor 202 or the like. This allows a variety of power semiconductors 202 to be controlled by a common drive device 100, thereby reducing the cost of the drive device 100.

[0041] The drive control unit 120 of this example includes an encoder 122 and a selection unit 124. The drive control unit 120 may further include a DA converter 126. The encoder 122 generates an encoded signal ENCD indicating a combination of the load current and element temperature values ​​based on the current detection signal ILOW and the temperature detection signals TL / TM / TH. In this example, the current detection signal ILOW indicates whether the load current belongs to the first current range I1 or the second current range I2. The temperature detection signals TL / TM / TH indicate whether the element temperature belongs to the first temperature range TL, the second temperature range TM, or the third temperature range TH. The encoder 122 of this example generates an encoded signal ENCD indicating which current range the load current belongs to and which temperature range the element temperature belongs to.

[0042] The selection unit 124 outputs a signal for setting the magnitude of the drive current based on the encoded signal ENCD. The selection unit 124 of this example reads out a setting record signal MEMD indicating the magnitude of the drive current corresponding to the encoded signal ENCD from the control memory 106. The selection unit 124 outputs a setting signal for setting the magnitude of the drive current based on the setting record signal MEMD. The setting signal of this example includes a first setting signal IDD and a second setting signal MW. The DA converter 126 converts the digital first setting signal IDD into an analog first setting signal IDREF.

[0043] The driver circuit 128 of this example generates two or more mirror currents according to the reference current, and selectively merges the two or more mirror currents to generate a drive current according to the reference current. The magnitude of the drive current has a predetermined ratio to the magnitude of the reference current. The first setting signal IDD and the first setting signal IDREF are signals for setting the magnitude of the reference current, and the second setting signal MW is a signal for setting the ratio of the drive current to the reference current.

[0044] The driver circuit 128 outputs a control signal OUT based on a setting signal from the drive control unit 120 and an internal signal OUTOFF from the input unit 104. When the internal signal OUTOFF indicates that the power semiconductor 202 is to be turned on, the driver circuit 128 of this example outputs a drive current having a magnitude according to the setting signal. The gate capacitances of the power semiconductor 202 and the current extracting power semiconductor 204 are charged according to the drive current, and the power semiconductor 202 and the current extracting power semiconductor 204 transition to the on state. By adjusting the drive current based on the load current and the element temperature, it is possible to suppress fluctuations in on-loss due to fluctuations in the load current and the element temperature, and also to suppress switching noise.

[0045] Fig. 2 is a diagram showing a configuration example of the driver circuit 128. The driver circuit 128 has a reference unit 130, two or more mirror circuits 136, and a current generating unit 150. The driver circuit 128 has a switch 138 and a switch 140 for at least one mirror circuit 136. The driver circuit 128 in the example of Fig. 2 has mirror circuits 136-1 to 136-5, but the number of mirror circuits 136 is not limited to this.

[0046] The reference unit 130 generates a reference current Ib. The reference unit 130 of the present example generates a reference current Ib having a magnitude corresponding to the first setting signal IDREF. The reference unit 130 of the present example includes a differential circuit 132, a reference circuit 134, a reference current generating unit 142, a resistor 146, and a switching circuit 148.

[0047] The reference current generating unit 142 generates a reference current Ib according to the output of the differential circuit 132. In this example, the reference current generating unit 142 is an n-MOSFET having a gate terminal to which the output of the differential circuit 132 is input. A resistor 146 is disposed between the source terminal of the reference current generating unit 142 and a reference potential PGND. The potential of the source terminal of the reference current generating unit 142 has a value according to the magnitude of the reference current Ib.

[0048] The differential circuit 132 adjusts the voltage input to the gate terminal of the reference current generating unit 142 so that the first setting signal IDREF is equal to the potential of the source terminal of the reference current generating unit 142. As a result, a reference current Ib according to the first setting signal IDREF flows in the reference current generating unit 142.

[0049] The switching circuit 148 switches whether or not to generate the reference current Ib in response to the internal signal OUTOFF. The switching circuit 148 generates the reference current Ib during a period when the power semiconductor 202 should be in an ON state, and does not generate the reference current Ib during a period when the power semiconductor 202 should be in an OFF state. By selectively controlling the period when the reference current Ib is generated, the current consumption of the driver circuit 128 can be reduced. In this example, the switching circuit 148 applies a reference potential PGND to the gate terminal of the reference current generating unit 142 during a period when the power semiconductor 202 should be in an OFF state. As a result, the reference current Ib does not flow through the reference current generating unit 142.

[0050] A reference current Ib flows through the reference circuit 134. In this example, the reference circuit 134 is a p-MOSFET directly connected between the reference current generating unit 142 and the high-voltage side power supply wiring VCC. The gate terminal and the drain terminal of the reference circuit 134 are connected to each other.

[0051] Each mirror circuit 136 is connected in parallel with the reference circuit 134. In this example, the mirror circuits 136 are p-MOSFETs with their source terminals connected to the power supply line VCC. The drain terminals of each mirror circuit 136 are connected to a common node 152. The gate terminal of each mirror circuit 136 is connected to the gate terminal of the reference circuit 134.

[0052] Since the same gate voltage as that of the reference circuit 134 is applied to each mirror circuit 136, a mirror current corresponding to the reference current Ib flows in each mirror circuit 136. The ratio between the mirror current flowing in each mirror circuit 136 and the reference current Ib is determined by the ratio between the total channel width of the mirror circuit 136 and the total channel width of the reference circuit 134. This ratio may be 1 or a value other than 1. Furthermore, this ratio in each mirror circuit 136 may be the same value or may be a different value.

[0053] Each of the switches 140 and 138 switches whether or not a mirror current flows through the corresponding mirror circuit 136. In this example, the switch 140 switches whether or not the same gate voltage as that of the reference circuit 134 is applied to the gate terminal of the corresponding mirror circuit 136. The switch 138 switches whether or not the gate terminal of the corresponding mirror circuit 136 is connected to the power supply line VCC. Each of the switches 140 and 138 is controlled by a second setting signal MW.

[0054] In this example, the second setting signal MW includes one or more bits corresponding to at least some of the mirror circuits 136. The logical value of each bit indicates whether or not a mirror current is passed through the corresponding mirror circuit 136. The second setting signal MW in this example has bits corresponding to the other mirror circuits 136-1 to 136-5 other than the mirror circuit 136-1. In this case, a mirror current passes through the mirror circuit 136-1 regardless of the second setting signal MW. The second setting signal MW sets whether or not a mirror current is passed through each of the other mirrors 136-2 to 136-5.

[0055] The current generating section 150 generates a drive current based on the mirror currents flowing through the two or more mirror circuits 136. The current generating section 150 of this example has a node 152 and an output control section 154.

[0056] The drain terminals of the mirror circuits 136 are connected to the node 152. Therefore, a drive current flows through the node 152, which is the sum of the mirror currents flowing through the mirror circuits 136. The second setting signal MW is used to switch whether or not a mirror current flows through each mirror circuit 136, thereby controlling the magnitude of the drive current.

[0057] The output control unit 154 controls whether to supply a drive current to the gate terminals of the power semiconductor 202 and the current extracting power semiconductor 204 or to connect the gate terminals to the reference potential PGND. The output control unit 154 in this example is an n-MOSFET to whose gate terminal an internal signal OUTOFF is input. When the internal signal OUTOFF is at an L level, the output control unit 154 is turned off and a drive current is supplied to the gate terminals of the power semiconductor 202 and the current extracting power semiconductor 204. This causes the power semiconductor 202 and the current extracting power semiconductor 204 to transition to an ON state. When the internal signal OUTOFF is at an H level, the output control unit 154 is turned on and the gate terminals of the power semiconductor 202 and the current extracting power semiconductor 204 are connected to the reference potential PGND. This causes the power semiconductor 202 and the current extracting power semiconductor 204 to transition to an OFF state.

[0058] The magnitude of the drive current is Ib×a. Ib indicates the magnitude of the reference current Ib, and a is the magnification of the drive current with respect to the reference current. The magnitude of the reference current Ib can be controlled by the first setting signal IDREF. The magnification a can be controlled by the second setting signal MW. The magnitude of the drive current can be controlled by controlling at least one of the magnitude of the reference current Ib and the magnification a. For example, the variable range of the drive current can be easily changed by adjusting the reference current Ib. Also, a variety of drive currents within the variable range can be easily generated by adjusting the magnification a.

[0059] The ratio of the mirror current to the reference current Ib may be different in at least two mirror circuits 136. The ratio may be different in all mirror circuits 136. The ratio of the mirror currents in the mirror circuit 136-k is denoted as ak. The ratio ak may be twice as large as the ratio ak-1. This makes it possible to widen the variable range of the drive current compared to when the mirror currents are uniform in magnitude.

[0060] FIG. 3 is a diagram for explaining an example of the operation of the encoder 122. The temperature detection unit 110 of this example compares the element temperature with one or more temperature thresholds (T1 and T2 in FIG. 3). The temperature threshold T2 of this example is higher than the temperature threshold T1. A region smaller than the temperature threshold T1 is a first temperature range TL, a region equal to or greater than the temperature threshold T1 and smaller than the temperature threshold T2 is a second temperature range TM, and a region equal to or greater than the temperature threshold T2 is a third temperature range TH. The temperature detection signal TL / TM / TH has bits corresponding to each of a plurality of temperature ranges. The temperature detection unit 110 of this example outputs a temperature detection signal TL / TM / TH in which the bit of the temperature range to which the element temperature belongs is set to 1 and the other bits are set to 0.

[0061] The current detection unit 108 of this example compares the load current with one or more current thresholds (one current threshold in the example of FIG. 3). In this example, a region smaller than the current threshold is a first current range IL, and a region equal to or greater than the current threshold is a second current range IH. The current detection signal ILOW of this example has a bit indicating which current range the load current belongs to. The current detection unit 108 of this example outputs a current detection signal ILOW with the bit set to 1 if the load current belongs to the first current range IL, and with the bit set to 0 if the load current belongs to the second current range IH.

[0062] The encoder 122 outputs an encoded signal ENCD indicating a combination of the values ​​of the temperature detection signals TL / TM / TH and the values ​​of the current detection signal ILOW. The encoded signal ENCD is a signal indicating a different value for each combination of the values ​​of the temperature detection signals TL / TM / TH and the values ​​of the current detection signal ILOW. The number of bits of the encoded signal ENCD (3 bits in this example) may be less than the total number of bits of the temperature detection signals TL / TM / TH and the current detection signal ILOW (4 bits in this example).

[0063] FIG. 4 is a diagram for explaining an example of the operation of the selection unit 124. The selection unit 124 of this example receives an encoded signal ENCD. The selection unit 124 reads out a setting record signal MEMD corresponding to the encoded signal ENCD from the control memory 106 and outputs it as a first setting signal IDD and a second setting signal MW. The selection unit 124 is associated with an address of the control memory 106 to be read out for each value of the encoded signal ENCD. The control memory 106 of the example of FIG. 4 has a storage area from 0 bits to 59 bits. The selection unit 124 reads out information of the bits corresponding to the encoded signal ENCD.

[0064] Fig. 5 is a diagram showing an example of information stored in the control memory 106. As described in Fig. 4, the control memory 106 stores the setting record signal MEMD corresponding to each value (i.e., detection state) of the encoding signal ENCD. As described above, the selection unit 124 reads out from the control memory 106 the setting record signal corresponding to the combination of the values ​​of the temperature detection signal TL / TM / TH and the current detection signal ILOW.

[0065] The setting record signal MEMD may be set in advance by a user or the like in accordance with the characteristics of the power semiconductor 202 to be driven. The control memory 106 is preferably a rewritable memory. This allows a drive current in accordance with the characteristics of the power semiconductor 202 to be generated simply by changing the settings of the control memory 106.

[0066] Fig. 6 is a diagram for explaining an operation example of the driving device 100. Fig. 6 shows the current-slope characteristic and the current-loss characteristic of the power semiconductor 202. The current-slope characteristic is a characteristic that indicates the relationship between the load current and a first slope dV / dt. When the power semiconductor 202 is turned on, the voltage between the main terminals of the power semiconductor 202 changes with time at a first slope dV / dt. The voltage between the main terminals of the power semiconductor 202 is, for example, an emitter-collector voltage or a source-drain voltage.

[0067] In Fig. 6, the dashed line shows the current-slope characteristic when the drive current is not changed. As shown in Fig. 6, the first slope dV / dt tends to increase as the load current decreases. In Fig. 6, the solid line shows the current-slope characteristic when the drive current is controlled.

[0068] The current-loss characteristic is a characteristic that shows the relationship between the load current and the turn-on loss Eon at the time of turn-on. The turn-on loss Eon is the energy loss that occurs in the power semiconductor 202 from the start of turn-on until the voltage between the main terminals reaches a set value. The turn-on loss Eon indicates the loss during one turn-on (one pulse). In FIG. 6, the dashed line shows the current-loss characteristic when the drive current is not changed. As shown in FIG. 6, the turn-on loss Eon tends to increase as the load current increases. In FIG. 6, the solid line shows the current-loss characteristic when the drive current is controlled.

[0069] The drive control unit 120 changes the drive current every time the load current exceeds one or more preset current thresholds. The drive control unit 120 may increase the drive current every time the load current exceeds one or more preset current thresholds. In the example of FIG. 6, one current threshold I1 is shown. In the first current range IL in which the load current is smaller than the current threshold I1, the drive current is controlled to be relatively small. Therefore, in the first current range IL, the first gradient dV / dt becomes relatively small. Therefore, switching noise can be reduced. In the first current range IL, the turn-on loss is not suppressed, but in the region where the load current is small, the turn-on loss is originally small. Therefore, in the first current range IL, the turn-on loss does not need to be suppressed by the drive current, or the turn-on loss may increase by the drive current.

[0070] When the load current belongs to the second current range IH that is equal to or greater than the current threshold I1, the drive control unit 120 increases the drive current compared to the first current range IL that is smaller than the current threshold I1. This reduces the turn-on loss. In the second current range IH, the switching noise increases with an increase in the drive current, but in the region where the load current is large, the switching noise is originally small, so the switching noise does not increase so much. As shown in FIG. 6, by increasing the drive current with an increase in the load current, it is possible to reduce both the turn-on loss and the switching noise.

[0071] FIG. 7 is a diagram for explaining an example of the operation of the driving device 100. FIG. 7 shows the temperature-slope characteristics and the temperature-loss characteristics of the power semiconductor 202. The temperature-slope characteristics are characteristics that show the relationship between the element temperature and the first slope dV / dt. In FIG. 7, the temperature-slope characteristics in the case where the driving current is not changed are shown by a broken line. As shown in FIG. 7, the first slope dV / dt tends to decrease as the element temperature increases. In FIG. 7, the temperature-slope characteristics in the case where the driving current is controlled are shown by a solid line.

[0072] The temperature-loss characteristic is a characteristic that shows the relationship between the element temperature and the turn-on loss Eon. In Fig. 7, the dashed line shows the temperature-loss characteristic when the drive current is not changed. As shown in Fig. 7, the turn-on loss Eon tends to increase as the element temperature increases. In Fig. 7, the solid line shows the temperature-loss characteristic when the drive current is controlled.

[0073] The drive control unit 120 changes the drive current every time the element temperature exceeds one or more preset temperature thresholds. The drive control unit 120 may increase the drive current every time the element temperature exceeds one or more preset temperature thresholds. In the example of FIG. 7, two temperature thresholds T1 and T2 are shown. In a first temperature range TL in which the element temperature is lower than the temperature threshold T1, the drive current is controlled to be relatively small. In a second temperature range TM in which the element temperature is equal to or higher than the temperature threshold T1 and lower than the temperature threshold T2, the drive control unit 120 increases the drive current compared to the first temperature range TL. In a third temperature range TH in which the element temperature is equal to or higher than the temperature threshold T2, the drive control unit 120 increases the drive current compared to the second temperature range TH.

[0074] By such control, even if the element temperature increases, the turn-on loss Eon can be suppressed. As shown in Fig. 7, each time the element temperature exceeds the temperature thresholds T1 and T2 and the drive current is increased, the first slope dV / dt increases and the switching noise increases. The drive control unit 120 may increase the drive current within a range in which the first slope dV / dt is equal to or smaller than a predetermined value α0.

[0075] The predetermined value α0 may be a first gradient dV / dt of the power semiconductor 202 in a state in which the element temperature of the power semiconductor 202 is at the lower limit of the operating temperature range of the power semiconductor 202 and the drive current is controlled to a minimum value other than 0 A. The minimum value of the drive current in this example refers to the minimum of the drive currents corresponding to the setting record signal MEMD stored in the control memory 106. In other words, it refers to the minimum of the drive currents that the driver circuit 128 can generate. However, the magnitude of the drive current is greater than 0 A.

[0076] The drive control unit 120 increases the drive current when the element temperature increases to the temperature threshold T1. The magnitude of the first gradient dV / dt at this time is set to α1. Similarly, the magnitude of the first gradient dV / dt when the element temperature reaches the temperature threshold T2 and the drive current is increased is set to α2. The increase in the drive current may be set so that both α1 and α2 are equal to or smaller than a predetermined value α0. α2 may be the same as α1 or may be different. By such control, the turn-on loss Eon can be reduced while suppressing an increase in switching noise.

[0077] 6 may be 0 A. The upper limit of the load current may be the rated current of the power semiconductor 202. The lower and upper limits of the element temperature in FIG 7 may be the lower and upper limits of the operating temperature range determined by the specifications of the power semiconductor 202.

[0078] The characteristics shown in Fig. 7 are those when the load current is a predetermined value. When the load current changes, the values ​​of the turn-on loss Eon and the first slope dV / dt change, as shown in Fig. 6. Therefore, when the load current changes, the values ​​of the turn-on loss and the first slope dV / dt shown in Fig. 7 shift. Similarly, when the element temperature changes, the values ​​of the turn-on loss and the first slope dV / dt shown in Fig. 6 shift.

[0079] The current threshold explained in FIG. 6 may be a common value even when the element temperature changes. In another example, the current threshold may be made different depending on the element temperature. For example, as the element temperature increases, the turn-on loss increases. For this reason, the current-loss characteristic shown in FIG. 6 shifts upward. The drive control unit 120 may reduce the current threshold as the element temperature increases. This makes it easier to suppress the turn-on loss.

[0080] The temperature threshold explained in FIG. 7 may be a common value even when the load current changes. In another example, the temperature threshold may be different depending on the load current. For example, as the load current increases, the turn-on loss increases. For this reason, the temperature-loss characteristic shown in FIG. 7 shifts upward. The drive control unit 120 may set the temperature threshold to be smaller as the load current increases. This makes it easier to suppress the turn-on loss.

[0081] FIG. 8 is a diagram showing an example of a current-slope characteristic. The current-slope characteristic in FIG. 8 is similar to the example in FIG. 6. The current-slope characteristic has a first linear region in which the first slope dV / dt changes linearly with respect to the load current, and a first nonlinear region in which the first slope dV / dt changes nonlinearly with respect to the load current. The first nonlinear region is a region in which the load current is smaller than that in the first linear region. As shown in FIG. 8, in a region in which the load current is close to the upper limit, the first slope dV / dt increases linearly as the load current decreases. On the other hand, in a region in which the load current is close to the lower limit, the first slope dV / dt increases nonlinearly as the load current decreases.

[0082] The first linear region may be a region in which a differential value obtained by differentiating the waveform of the current-slope characteristics with respect to the load current falls within a predetermined range with respect to a reference value. In other words, the first linear region may be a region in which the differential value is approximately equal to the reference value. The reference value may be a differential value at a reference point 161 in the waveform of the current-slope characteristics. The reference point 161 may be a point at which the load current indicates an upper limit value. The predetermined range may be, for example, ±50%, ±30%, or ±10% of the reference value.

[0083] At least one current threshold may be set in the first nonlinear region. In the example of FIG. 8, the current threshold I1 is set in the first nonlinear region. In the first nonlinear region, the degree of decrease in the first slope dV / dt caused by reducing the drive current is large. Therefore, by setting the current threshold I1 in the first nonlinear region, switching noise can be effectively suppressed. All the current thresholds may be set in the first nonlinear region, or some of the current thresholds may be set in the first linear region. The number of current thresholds set in the first nonlinear region may be greater than the number of current thresholds set in the first linear region.

[0084] FIG. 9 is a diagram showing an example of temperature-loss characteristics. The temperature-loss characteristics in FIG. 9 are similar to the example in FIG. 7. The temperature-loss characteristics have a second linear region in which the turn-on loss Eon changes linearly with respect to the element temperature, and a second nonlinear region in which the turn-on loss Eon changes nonlinearly with respect to the element temperature. The second nonlinear region is a region in which the element temperature is higher than that in the second linear region. As shown in FIG. 9, in a region in which the element temperature is close to the lower limit, the turn-on loss Eon increases linearly with an increase in the element temperature. On the other hand, in a region in which the element temperature is close to the upper limit, the turn-on loss Eon increases nonlinearly with an increase in the element temperature.

[0085] The second linear region may be a region in which the derivative value obtained by differentiating the waveform of the temperature-loss characteristic with respect to the element temperature falls within a predetermined range with respect to the reference value. In other words, the second linear region may be a region in which the derivative value is approximately equal to the reference value. The reference value may be a derivative value at a reference point 162 in the waveform of the temperature-loss characteristic. The reference point 162 may be a point at which the element temperature indicates a lower limit value. The predetermined range may be, for example, ±50%, ±30%, or ±10% of the reference value.

[0086] At least one temperature threshold may be set in the second nonlinear region. In the example of FIG. 9, the temperature thresholds T1 and T2 are set in the second nonlinear region. In the second nonlinear region, the degree of suppression of the turn-on loss by increasing the drive current is large. Therefore, by setting the temperature thresholds in the second nonlinear region, the turn-on loss can be effectively suppressed. All the temperature thresholds may be set in the second nonlinear region, and some of the temperature thresholds may be set in the second linear region. The number of temperature thresholds set in the second nonlinear region may be greater than the number of temperature thresholds set in the second linear region.

[0087] FIG. 10 is a diagram showing an example of temperature-slope characteristics. The temperature-slope characteristics in FIG. 10 are similar to the example in FIG. 7. The temperature-slope characteristics have a third linear region in which the first slope dV / dt changes linearly with respect to the element temperature, and a third nonlinear region in which the first slope dV / dt changes nonlinearly with respect to the element temperature. The third nonlinear region is a region in which the element temperature is higher than the third linear region. As shown in FIG. 10, in a region in which the element temperature is close to the lower limit, the first slope dV / dt decreases linearly with an increase in the element temperature. On the other hand, in a region in which the element temperature is close to the upper limit, the first slope dV / dt decreases nonlinearly with an increase in the element temperature.

[0088] The third linear region may be a region in which a differential value obtained by differentiating the waveform of the temperature-slope characteristics with respect to the element temperature falls within a predetermined range with respect to a reference value. In other words, the third linear region may be a region in which the differential value is approximately equal to the reference value. The reference value may be a differential value at a reference point 163 in the waveform of the temperature-slope characteristics. The reference point 163 may be a point at which the element temperature indicates a lower limit value. The predetermined range may be, for example, ±50%, ±30%, or ±10% of the reference value.

[0089] At least one temperature threshold may be set in the third nonlinear region. In the example of FIG. 10, the temperature thresholds T2 to T4 are set in the third nonlinear region. As described in FIG. 7, when the drive current is increased, the first gradient dV / dt increases and the switching noise increases, but the turn-on loss can be reduced. For example, by increasing the drive current within a range in which the first gradient dV / dt does not exceed the reference value α0, the turn-on loss can be reduced while suppressing the increase in switching noise. Therefore, by increasing the drive current every time the first gradient dV / dt becomes smaller than the reference value α0 to a certain extent, the turn-on loss can be efficiently reduced. In a region in which the first gradient dV / dt decreases significantly with respect to the increase in the element temperature, such as the third nonlinear region, the interval between the temperature thresholds is narrowed, so that the drive current can be increased before the first gradient dv / dt becomes too small. For this reason, the turn-on loss can be efficiently reduced. Furthermore, in a region such as the third nonlinear region where the first slope dV / dt decreases significantly with increasing element temperature, if the interval between temperature thresholds is made too large, the fluctuation of the first slope dV / dt when the element temperature exceeds the temperature threshold may become too large, which may result in noise, etc.

[0090] The number of temperature thresholds set in the third nonlinear region may be greater than the number of temperature thresholds set in the third linear region. In this example, a temperature threshold T1 is set in the third linear region. The density of the temperature thresholds set in the third nonlinear region may be greater than the density of the temperature thresholds set in the third linear region. The density of the temperature thresholds is the number of temperature thresholds included in each region divided by the size of the temperature range of each region.

[0091] The difference between two adjacent temperature thresholds described in each example in this specification may be smaller as the temperature threshold is higher. In this case, three or more temperature thresholds are set. Two adjacent temperature thresholds refer to two temperature thresholds that are adjacent to each other when multiple temperature thresholds are arranged on a temperature axis. In the example of FIG. 10, temperature thresholds T1, T2, T3, and T4 are arranged on the temperature axis from the lower limit to the upper limit. The difference between temperature thresholds T3 and T4 may be smaller than the difference between temperature thresholds T1 and T2. In other words, the difference between the two highest temperature thresholds may be smaller than the difference between the two lowest temperature thresholds.

[0092] The difference between two adjacent temperature thresholds in the third nonlinear region may be smaller than the difference between two adjacent temperature thresholds in the third linear region. Two adjacent temperature thresholds in the third nonlinear region may both be included in the third nonlinear region. Two adjacent temperature thresholds in the third linear region may both be included in the third linear region. When only one temperature threshold T1 is set in the third linear region as in the example of FIG. 10, a difference D12 between the temperature threshold T2 next to the temperature threshold T1 and the temperature threshold T1 may be used as the difference between two adjacent temperature thresholds in the third linear region.

[0093] 10, the value of the difference D23 between the temperature thresholds T2 and T3 is greater than the value of the difference D12. The value of the difference D34 between the temperature thresholds T3 and T4 is greater than the value of the difference D12. The value of the difference D34 may be greater than the value of the difference D23 or may be the same as the value of the difference D23.

[0094] 11 is a diagram showing an example of the time waveforms of the load current Ic and the voltage Vce between the main terminals when the power semiconductor 202 is turned on. When a drive current is supplied to the gate terminal of the power semiconductor 202 at time t0 and exceeds the threshold voltage of the power semiconductor 202, the load current Ic increases, and the voltage Vce between the main terminals decreases from the voltage when the power semiconductor 202 is off (VH in this example) to the reference voltage (0 V in this example).

[0095] In this specification, the absolute value of the slope of the waveform of the main terminal voltage Vce from 0.9×VH to 0.1×VH at turn-on is defined as a first slope dV / dt. Also, the energy loss in the power semiconductor 202 during the period from when the main terminal voltage Vce decreases from VH to 0V is defined as a turn-on loss Eon.

[0096] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention. [Explanation of symbols]

[0097] 100 Drive device, 102 Power supply section, 104 Input section, 106 Control memory, 108 Current detection section, 110 Temperature detection section, 120 Drive control section, 122 Encoder, 124 Selection section, 126 DA converter, 128 Driver circuit, 130 Reference section, 132 Differential circuit, 134 Reference circuit, 136 Mirror circuit, 138, 140...switch, 142...reference current generating section, 146...resistor, 148...switching circuit, 150...current generating section, 152...node, 154...output control section, 161, 162, 163...reference point, 200...output device, 202...power semiconductor, 204...power semiconductor for current extraction, 206...temperature sensor, 300...power supply device

Claims

1. A drive device for a power semiconductor, At least one of a current detection unit that detects the magnitude of a load current supplied from the power semiconductor to a load and a temperature detection unit that detects an element temperature of the power semiconductor; a drive control unit that controls a drive current of the power semiconductor based on at least one of the load current and the element temperature; a driver circuit for supplying the driving current to the power semiconductor; Equipped with The driver circuit includes: a reference section for generating a reference current; two or more mirror circuits provided in parallel with each other, each of which generates a mirror current corresponding to the reference current; a current generating unit that generates the drive current based on currents flowing through the two or more mirror circuits; having The drive control unit controls the drive current by controlling whether or not the mirror current is output to the current generating unit for one or more of the mirror circuits. Drive unit.

2. The drive control unit controls the magnitude of the reference current to control the drive current. The drive device according to claim 1 .

3. The ratio of the mirror current to the reference current is different in at least two of the mirror circuits. The drive device according to claim 1 .

4. a control memory that records the drive current to be set for each of a plurality of detection states including at least one of the load current and the element temperature; The drive control unit reads out a setting record signal indicating the drive current from the control memory based on the detected state corresponding to at least one of the detected load current and the element temperature. The drive device according to claim 1 .

5. The drive control unit changes the drive current every time the load current exceeds one or more preset current thresholds. A drive arrangement according to any one of claims 1 to 4.

6. When the power semiconductor is turned on, a voltage between the main terminals of the power semiconductor changes with respect to time with a first slope; a current-slope characteristic which is a characteristic of the first slope with respect to the load current has a first linear region in which the first slope changes linearly with respect to the load current, and a first nonlinear region in which the first slope changes nonlinearly with respect to the load current in a region in which the load current is smaller than the first linear region; At least one of the current thresholds is set in the first nonlinear region. The drive device according to claim 5.

7. The drive control unit changes the drive current every time the element temperature exceeds one or more preset temperature threshold values. A drive arrangement according to any one of claims 1 to 4.

8. The temperature-loss characteristic, which is a characteristic of the turn-on loss of the power semiconductor with respect to the element temperature, has a second linear region in which the turn-on loss changes linearly with respect to the element temperature, and a second nonlinear region in which the turn-on loss changes nonlinearly with respect to the element temperature in a region in which the element temperature is higher than the second linear region, At least one of the temperature thresholds is set in the second nonlinear region.

8. The drive device according to claim 7.

9. When the power semiconductor is turned on, a voltage between the main terminals of the power semiconductor changes with respect to time with a first slope; The power semiconductor has a set operating temperature range, The drive control unit controls the drive current so that the first gradient when the drive current is increased is equal to or smaller than the first gradient when the element temperature is at the lower limit of the operating temperature range and the drive current is at a minimum value. The drive device according to claim 4.

10. Three or more temperature thresholds are set, The difference between adjacent temperature thresholds is smaller as the temperature thresholds are higher.

8. The drive device according to claim 7.

11. When the power semiconductor is turned on, a voltage between the main terminals of the power semiconductor changes with respect to time with a first slope; a temperature-slope characteristic which is a characteristic of the first slope with respect to the element temperature has a third linear region in which the first slope changes linearly with respect to the element temperature, and a third nonlinear region in which the first slope changes nonlinearly with respect to the element temperature in a region where the element temperature is higher than the third linear region; A difference between adjacent temperature thresholds in the third nonlinear region is smaller than a difference between adjacent temperature thresholds in the third linear region. The drive arrangement according to claim 10.

12. A drive device for a power semiconductor, A current detection unit that detects the magnitude of a load current supplied from the power semiconductor to a load; A temperature detection unit that detects an element temperature of the power semiconductor; a drive control unit that controls a drive current of the power semiconductor based on the load current and an element temperature; a control memory that records the drive current to be set for each of a plurality of combinations of the load current value and the element temperature value; Equipped with The drive control unit reads out from the control memory a setting record signal indicating the drive current corresponding to a combination of the detected value of the load current and the value of the element temperature. Drive unit.

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