POWER ELECTRONIC DEVICE AND SENSING METHOD FOR GaN DIE INCLUDED THEREIN

Abstract

The invention relates to a power electronic device and a sensing method for a GaN die included therein. A power electronic device includes a first semiconductor die and a second semiconductor die. The first die includes: a main GaN power transistor; a first GaN current sensing transistor having a source electrically connected to the second current sensing terminal; a second GaN current sensing transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device electrically connecting the drain of the second GaN current sensing transistor to the first current sensing terminal. The second die includes a current sensing circuit electrically connected to the current sensing terminal and a short circuit detection circuit. The short circuit detection circuit detects when a drain current of the main GaN power transistor exceeds a predetermined value, and when the main GaN power transistor is saturated.

Description

Technical Field

[0001] The present disclosure relates generally to power electronics and, more particularly, to sensing methods for GaN dies included in power electronics. Background Art

[0002] GaN (Gallium Nitride) technology enables higher switching frequencies, for example above 200 to 250kHz. Many power electronics applications approach such high frequencies with lower operating duty cycles, making it more difficult to perform accurate current sensing fast enough to track the current through the GaN power device in the on phase in a very short time. Another problem is the aging of the main GaN power device relative to the sensing device, which causes the current sensing accuracy to degrade over time. Another problem is sensing voltages that can be as high as 600V or more using low voltage technologies such as Si (Silicon). Another problem is accurate drain voltage sensing and saturation detection of the main GaN power device without increasing the complexity or terminal count of the die (chip).

[0003] Therefore, there is a need for improved current sensing technology for GaN dies. Summary of the invention

[0004] According to an embodiment of a power electronic device, the power electronic device includes a first semiconductor die and a second semiconductor die, the first semiconductor die including: a first current sensing terminal; a second current sensing terminal; a main GaN (gallium nitride) power transistor; a first GaN current sensing transistor having a source electrically connected to the second current sensing terminal and a drain electrically connected to the drain of the main GaN power transistor; a second GaN current sensing transistor having a source electrically connected to the source of the main GaN power transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device electrically connecting the drain of the second GaN current sensing transistor to the first current sensing terminal; the second semiconductor die includes a current sensing circuit and a short circuit detection circuit electrically connected to the first current sensing terminal and the second current sensing terminal of the first semiconductor die, wherein the short circuit detection circuit is configured to detect: when the drain current of the main GaN power transistor exceeds a predetermined value, and when the main GaN power transistor is in saturation.

[0005] According to one embodiment of a sensing method for a GaN (gallium nitride) die, the GaN die includes: a main GaN power transistor; a first GaN current sensing transistor having a source electrically connected to a second current sensing terminal of the GaN die and a drain electrically connected to a drain of the main GaN power transistor; a second GaN current sensing transistor having a source electrically connected to the source of the main GaN power transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device that connects the second GaN current sensing transistor to the main GaN power transistor. The drain of the current sensing transistor is electrically connected to a first current sensing terminal of the GaN die, and the sensing method includes: sensing a scaled-down copy of the current flowing in the main GaN power transistor based on a voltage at the first current sensing terminal of the GaN die and a voltage at a second current sensing terminal of the GaN die; detecting when the main GaN power transistor is in saturation based on the voltage at the first current sensing terminal of the GaN die and a first reference voltage; and detecting when the drain current of the main GaN power transistor exceeds a predetermined value based on the voltage at the second current sensing terminal of the GaN die and the second reference voltage.

[0006] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The elements in the drawings are not necessarily drawn to scale relative to each other. The same reference numerals represent corresponding similar parts. Unless mutually exclusive, the features of the various illustrated embodiments may be combined. The embodiments are depicted in the drawings and described in detail in the following description.

[0008] Figure 1 A schematic diagram of one embodiment of a power electronic device is illustrated that includes a first semiconductor die having a GaN power transistor and a GaN current sensing transistor, and a second semiconductor die having a current sensing circuit and a short circuit detection circuit.

[0009] Figure 2 A schematic diagram of a power electronic device according to another embodiment is illustrated. DETAILED DESCRIPTION

[0010] An embodiment of a power electronic device and a sensing method for a GaN die (chip) included in the power electronic device is described herein, the sensing method using a second die that includes a current sensing circuit and a short circuit detection circuit electrically connected to a current sensing terminal of the GaN die. The short circuit detection circuit is configured to detect when the drain current of the main GaN power transistor exceeds a predetermined value and when the main GaN power transistor is in saturation. When the short circuit detection circuit detects either situation, corrective action can be taken immediately, for example, by overriding the gate drive signal to shut down the main GaN power transistor. The GaN die has a current sensing readout circuit device with low voltage protection, enabling current sensing using low voltage technologies such as Si (silicon).

[0011] Next, exemplary embodiments of a power electronic device and a corresponding sensing method are described with reference to the accompanying drawings.

[0012] Figure 1 An embodiment of a power electronic device 100 is illustrated. The power electronic device 100 includes a first semiconductor die 102 and a second semiconductor die 104. The first semiconductor die 102 and the second semiconductor die 104 may be packaged together in the same package, assembled in the same module, or attached to the same circuit board.

[0013] The first semiconductor die 102 is a GaN (gallium nitride) die that includes GaN devices. The second semiconductor die 104 is a Si (silicon) die that includes Si devices. For example, the power electronic device 100 can utilize other semiconductor technologies such as SiC. Therefore, the functions of the devices included in the power electronic device 100 are technology independent, but are described herein in the context of GaN technology for the first semiconductor die 102 and in the context of Si technology for the second semiconductor die 104. Therefore, the transistors, diode devices, etc. described herein and included in the power electronic device 100 can be GaN devices, Si devices, SiC devices, etc.

[0014] According to this understanding, the GaN die 102 includes a first current sensing terminal 102, a second current sensing terminal 104, a main GaN power transistor GaN Power , the first GaN current sensing transistor GaN Sense1 , and a second GaN current sensing transistor GaN Sense2 The GaN die 102 includes additional terminals, such as a gate (control) terminal 110. For example, the terminals 106, 108, 110 may be bonding (contact) pads, pins, balls, pillars, etc. at the front side and / or back side of the GaN die 102. Sense1 、GaN Sense2and the main GaN power transistor GaN Power The on / off state of the GaN die 102 is controlled by a gate signal “Gate” that drives the common (shared) gate terminal 110 of the GaN die 102 .

[0015] The main GaN power transistor GaN included in the GaN die 102 Power It can be part of the low-side switching device of any type of power electronic device that operates at relatively high frequencies, such as above 200 to 250kHz, and requires accurate current sensing. For example, the main GaN power transistor GaN Power Can be part of a low-side switch for power, boost converter, flyback converter, PFC (power factor correction) stage, etc.

[0016] The first GaN current sensing transistor GaN Sense1 The source S Sense1 The first GaN current sensing transistor GaN is electrically connected to the second current sensing terminal 108. Sense1 The drain D Sense1 Electrically connected to the main GaN power transistor GaN Power The drain D Power The second GaN current sensing transistor GaN Sense2 The source S Sense2 Electrically connected to the main GaN power transistor GaN Power The source S Power .

[0017] The first GaN current sensing transistor GaN Sense1 GaN with main GaN power transistor Power The size ratio of the GaN current sensing transistor is 1:K, and the second GaN current sensing transistor GaN Sense2 GaN with main GaN power transistor Power The size ratio of the first GaN current sensing transistor GaN is 1:N*K. Sense1 GaN is generated in the main GaN power transistor Power The current I flowing in POWER A scaled-down (1:K) copy of .

[0018] In one embodiment, the first GaN current sensing transistor GaN Sense1 The channel width of the main GaN power transistor GaN Power The channel width of the second GaN current sensing transistor GaN Sense2 With the first GaN current sensing transistor GaN Sense1It also has a scaled-down channel width (1:N) compared to the main GaN power transistor GaN Power The current sensing circuit 112 included in the second semiconductor die 104 senses the current at the main GaN power transistor GaN based on the voltage at the first current sensing terminal 106 of the GaN die 102 and the voltage at the second current sensing terminal 108 of the GaN die 102. Power The current I flowing in POWER A scaled-down copy of .

[0019] For example, the main GaN power transistor GaN included in the GaN die 102 Power and GaN current sensing transistorsGaN Sense1 、GaN Sense2 It can be a normally off (i.e., enhancement mode) device. For a normally off device, in the absence of an appropriate voltage applied to the GaN transistor GaN Power / GaN Sense1 / GaN Sense2 The gate G Power / G Sense1 / G Sense2 In the case of GaN transistors, Power / GaN Sense1 / GaN Sense2 The drain and source D Power , S Power / D Sense1 , S Sense1 / D Sense2 , S Sense2 There is no current conduction channel between them.

[0020] In one embodiment, the main GaN power transistor GaN Power and GaN current sensing transistorsGaN Sense1 、GaN Sense2 is a gate injection transistor (GIT) which is a hybrid drain HEMT (High Electron Mobility Transistor) with a p-GaN gate, which results in a normally-off power switch. The gate signal "Gate" is the gate current injection signal for the GIT device.

[0021] In another embodiment, the main GaN power transistor GaN Power and GaN current sensing transistorsGaN Sense1 、GaN Sense2It is a Schottky gate HEMT (High Electron Mobility Transistor) in which the p-GaN layer can be partially depleted or fully depleted by the metal / p-GaN Schottky junction depending on the doping concentration and thickness of the p-GaN layer. The gate signal "Gate" is a gate voltage signal for the Schottky gate HEMT.

[0022] The GaN die 102 also includes a main GaN power transistor GaN connected in series Power The drain D Power With the second GaN current sensing transistor GaN Sense2 The drain D Sense2 In one embodiment, the diode device 114 is a GaN transistor GaN Diode , which has a GaN transistor electrically connected to the main GaN Power The drain D Power The drain D Diode , electrically connected to a second GaN current sensing transistor GaN Sense2 The drain D Sense2 The source S Diode , and electrically connected to the GaN transistor GaN Diode The drain D Diode The gate G Diode In another embodiment, the diode device 114 is a pn diode PN having a gate electrode electrically connected to the main GaN power transistor GaN Power The drain D Power an anode of the GaN transistor and electrically connected to a second GaN current sensing transistor GaN Sense2 The drain D Sense2 The cathode of the pn diode PN Figure 1 The GaN transistor is shown in dashed lines to indicate the GaN transistor configured as a gate-controlled diode of the HEMT. Diode A pn diode or PN diode can be electrically connected in series with the main GaN power transistor GaN Power The drain D Power With the second GaN current sensing transistor GaN Sense2 The drain D Sense2 between.

[0023] In either case, the diode device 114 clamps the voltage at the first resistor R1 when the main GaN power transistor GaN Power When turned off, this voltage becomes the main GaN power transistor GaN Power The drain voltage of the main GaN power transistor is minus the diode voltage drop. Power When the main GaN power transistor GaN PowerWhen turned on, the voltage protection device 116 in the GaN die 102 and the second GaN current sensing transistor GaN Sense2 As a single switch with twice the series resistance, it produces half the current. Power When entering saturation, the diode device 114 enters forward conduction, so that when the diode device 114 enters forward conduction, the current I SW The current flows from the diode device 114 into the voltage protection device 116 and into the first resistor R1. This causes the voltage across the first resistor R1 to increase, thereby providing an indication that the main GaN power transistor is saturated, which is detected by the short circuit detection circuit 118 included in the second semiconductor die 104 without the need for additional readout circuitry or terminals on the GaN die 102.

[0024] The diode device 114 included in the GaN die 102 is subjected to the main GaN power transistor GaN Power The same drain voltage should make the second GaN current sensing transistor GaN Sense2 With the main GaN power transistor GaN Power However, this now causes the second GaN current sensing transistor GaN Sense2 The drain D Sense2 In the case where the current sensing circuit 112 included in the second die 104 and electrically connected to the first current sensing terminal 102 and the second current sensing terminal 104 of the GaN die 102 is implemented using a low voltage technology such as Si (silicon), protection against the high voltage is required.

[0025] The GaN die 102 provides low voltage protection for the current sensing circuit 112 included in the second die 104 via the voltage protection device 116. The voltage protection device 116 connects the second GaN current sensing transistor GaN Sense2 The drain D Sense2 is electrically connected to the first sense terminal 102 and protects the current sensing circuit 112 from the main GaN power transistor GaN Power In one embodiment, the voltage protection device 116 is a GaN transistor such as a Schottky gate HEMT or GIT device. SW , which has a second GaN current sensing transistor G electrically connected to Sense2 The drain D Sense2 The drain D SW , a source S electrically connected to the first current sensing terminal 106 of the GaN die 102 SW, and a gate G electrically connected to the gate terminal 110 of the GaN die 102 SW The gate terminal 110 of the GaN die 102 is also electrically connected to the main GaN power transistor GaN Power The gate G Power and a first GaN current sensing transistor GaN Sense1 The gate G Sense1 , so that the second semiconductor die 104 drives the GaN transistor GaN included in the GaN die 102 using the common gate signal “Gate” Power 、GaN Sense1 、GaN Sense2 、GaN SW Each transistor in the

[0026] By making the device GaN Sense2 and GaN SW Both see the same GaN as the main GaN power transistor during the turn-off phase. Power At approximately the same drain voltage, the drain charge trapping phenomenon associated with GaN-based high electron mobility transistors (HEMTs) is added to the second GaN current sensing transistor GaN Sense2 and high voltage protection GaN transistorsGaN SW In GaN technology, there is a minimum width beyond which the matching becomes very poor. Figure 1 In the GaN Sense1 、GaN Sense2 and GaN Power matching, by including high voltage protection GaN transistors GaN SW And use high voltage to protect GaN transistorsGaN SW As a sensing device (which also has the same off-phase drain stress), the Kilis factor is improved. This configuration brings an additional benefit, namely that GaN SW and GaN Sense2 The two resistors R GaN_SW and R GaN_Sense2 The sum of the required sensing currents reduces the need for GaN power transistors and enables Power and another sensing device GaN Sense1 The area of ​​the match is doubled. Therefore, the new N ratio becomes:

[0027]

[0028] Where R GaN_Sense1 The first GaN current sensing transistor Sense1 resistance.

[0029] Therefore, the resistor ratio is designed according to the N factor expressed in equation (1). Another benefit is that the temperature coefficient of the current sensing readout circuitry included in the GaN die 102 can be relatively small relative to the main GaN power transistor GaN Power In this case, by changing the values ​​of the first resistor R1 and the second resistor R2, the GaN current sensing transistor GaN Sense1 、GaN Sense2 The temperature coefficient of the GaN power transistor is different from that of the main GaN Power Since the second resistor R2 reduces the temperature coefficient of the first GaN current sensing transistor GaN Sense1 The sense current flowing in the GaN current sensing transistor 116 is thus composed of the voltage protection device 116 and the second GaN current sensing transistor GaN Sense2 The branch compensates for the lower sense current, making the sense current relative to the main GaN power transistor GaN Power The current I POWER Ratio measure of (with factor N*K).

[0030] In addition, the high voltage protection GaN transistor GaN in parallel with the resistor R1 SW and a second GaN current sensing transistor GaN Sense2 Enables sensing current to protect GaN transistors against high voltages SW and a second GaN current sensing transistor GaN Sense2 are not sensitive to aging effects because their changes do not have such a significant impact on the final sensed current.

[0031] In addition, the first GaN current sensing transistor GaN Sense1 The current is used for the load and is not drawn from the auxiliary power supply V1 included in the second die 104. This allows the first GaN current sensing transistor GaN Sense1 The size of has a large enough area for good matching and therefore better uniformity of the GaN device well charge distribution. Figure 1 The illustrated embodiment also enables bidirectional current sensing.

[0032] By converting the power current I POWER Dividing by factors K and N, the current required for sensing can be minimized, where R1 = R2*N. By using resistor R GaN_SW and R GaN_Sense2 The two act as sensing fingers, which can further increase the ratio N. High voltage protection GaN transistor GaN SWThe smaller fingers are used as switches during the off phase to protect the low voltage devices of the current sensing circuit 112 included in the second die 104, and are used as sensing fingers during the on phase. Simulations show that the smaller fingers have the same Power Different temperature coefficients, but appropriate sizing of resistors R1 and R2 allows adjustment of the temperature coefficient.

[0033] Both the current sensing circuit 112 and the short circuit detection circuit 118 included in the second semiconductor die 104 are electrically connected to the first current sensing terminal 106 and the second current sensing terminal 108 of the GaN die 102 via respective terminals 120, 122 of the second die 104. The second semiconductor die 104 also includes a driver output terminal 124 electrically connected to the gate terminal 110 of the GaN die 102 for providing a common gate signal “Gate” to the GaN die 102. The common gate signal “Gate” may be a gate current injection signal for a GIT device, or a gate voltage signal for a Schottky gate HEMT, as previously explained herein.

[0034] The short circuit detection circuit 118 included in the second die 104 monitors the voltage across the first resistor R1 connected between the first current sensing terminal 106 of the GaN die 102 and ground to detect the main GaN power transistor GaN Power The short circuit detection circuit 118 also monitors the voltage across a second resistor R2 connected between the second current sensing terminal 108 of the GaN die 102 and ground to detect when the main GaN power transistor GaN Power The drain current I POWER When the preset value I is exceeded POWER_TH Therefore, the short circuit detection circuit 118 detects the excessive drain current condition via the second current sensing terminal 108 of the GaN die 102 and detects the main GaN power transistor GaN via the first current sensing terminal 106 of the GaN die 102. Power saturation.

[0035] Main GaN Power TransistorGaN Power The magnitude of the saturation current in the main GaN power transistor significantly affects the GaN Power For example, the GaN connected to the main GaN power transistor Power The drain D Power The short circuit across the load causes a high drain-to-source voltage and a high current to be applied simultaneously, which is driven by the main GaN power transistor GaN in saturation. Power The current I POWER This situation leads to the main GaN power transistor GaN PowerThe short circuit detection circuit 118 included in the second die 104 detects the high power dissipation in the main GaN power transistor GaN Power when saturation occurs to prevent this destructive failure.

[0036] The second semiconductor die 104 includes a gate driver 126 to apply a common gate signal “Gate” to the gate terminal 110 of the GaN die 102. If the short circuit detection circuit 118 included in the second die 104 detects that the main GaN power transistor GaN Power In saturation, the short-circuit detection circuit 118 overrides the gate signal “Gate”. If the main GaN power transistor GaN Power The drain current I POWER Exceeding the preset value I POWER_TH , the short-circuit detection circuit 118 also covers the gate signal "Gate". When the gate signal "Gate" is covered, the main GaN power transistor GaN Power Forced to shut down.

[0037] Figure 2 One embodiment of a current sensing circuit 112 and a short circuit detection circuit 118 included in the second semiconductor die 104 is illustrated. Figure 2 , the current sensing circuit 112 includes an operational amplifier 200 having a positive (“+”) input electrically connected to a first current sensing terminal 106 of the GaN die 102 via a corresponding terminal 120 of the second die 104. A negative (“−”) input of the operational amplifier 200 is electrically connected to a second current sensing terminal 108 of the GaN die 102 via a corresponding terminal 122 of the second die 104.

[0038] The output of the operational amplifier 200 controls the current source circuit 202 of the current sensing circuit 112 so that the voltages across the first resistor R1 and the second resistor R2 are substantially equal. The current source circuit 202 is controlled by the output of the comparator 200 and forces the current I SW The voltage protection device 116 through the GaN die 102 . The amplitude of the current sense signal Isense output by the current source circuit 202 is generated to minimize the voltage difference across the first current sense terminal 106 and the second current sense terminal 108 of the GaN die 102 .

[0039] exist Figure 2, the current source circuit 202 includes a first pMOS transistor Q1 and a second pMOS transistor Q2, both of which are controlled by the output of the comparator 200 and have a source electrically connected to the voltage source V1. The drain of the first pMOS transistor Q1 is electrically connected to the first current sensing terminal 106 of the GaN die 102 via the corresponding terminal 122 of the second die 104. The drain of the second pMOS transistor Q2 forms the current sensing output Isense of the current sensing circuit 112.

[0040] exist Figure 2 In the embodiment, the voltage protection device 116 of the GaN die 102 is implemented as a GaN transistor GaN SW , which is used exclusively as a switching device and is configured as the main GaN power transistor GaN Power When the main GaN power transistor GaN Power Turn off when off. GaN switching deviceGaN SW The drain D SW electrically connected to a second GaN current sensing transistor GaN Sense2 The drain D Sense2 , and GaN switching devices GaN SW The source S SW The first current sensing terminal 106 is electrically connected to the GaN die 102. The GaN switching device GaN SW The gate G SW and source S SW With the second GaN current sensing transistor GaN Sense2 The drain D Sense2 The current source circuit 202 of the current sensing circuit 112 included in the second die 104 sets the current flowing through the GaN switching device GaN based on the comparator output. SW The current I SW Other types of current sensing circuit implementations may be used in the second die 104 .

[0041] exist Figure 2 In the embodiment, the short circuit detection circuit 118 included in the second die 104 includes a first comparator 204 and a second comparator 206, wherein the first comparator 204 is used to indicate that the main GaN power transistor GaN in the GaN die 102 Power When the GaN power transistor GaN is in saturation, the second comparator 206 is used to indicate Power The drain current I POWER When the preset value I is exceeded POWER_TH. The non-inverting (“+”) input of the first comparator 204 is electrically connected to the first current sensing terminal 106 of the GaN die 102 via the corresponding terminal 120 of the second die 104. Since the first resistor R1 electrically connects the first current sensing terminal 106 of the GaN die 102 to the ground, the non-inverting (“+”) input of the first comparator 204 corresponds to the voltage across the first resistor R1. The inverting (“-”) input of the first comparator 204 is electrically connected to the first reference voltage source 208. The non-inverting (“+”) input of the second comparator 206 is electrically connected to the second current sensing terminal 108 of the GaN die 102 via the corresponding terminal 122 of the second die 104. Since the second resistor R2 electrically connects the second current sensing terminal 108 of the GaN die 102 to the ground, the non-inverting (“+”) input of the second comparator 206 corresponds to the voltage across the second resistor R2. The inverting (“-”) input of the second comparator 206 is electrically connected to the second reference voltage source 210.

[0042] When the voltage across the first resistor R1 exceeds the first reference voltage source 208, the output SCP_SAT of the first comparator 204 becomes high, thereby indicating that the main GaN power transistor GaN in the GaN die 102 is Power When the voltage across the second resistor R2 exceeds the second reference voltage source 210, the output SCP_SNS of the second comparator 206 becomes high, thereby indicating that the main GaN power transistor GaN Power The drain current I POWER Exceeding the preset value I POWER_TH Therefore, the short circuit detection circuit 118 detects the main GaN power transistor GaN via the first comparator 204. Power saturation, and detects the drain current excess condition at lower drain current at room temperature and low temperature via the second comparator 206.

[0043] exist Figure 2 , the short circuit detection circuit 118 included in the second die 104 further includes a logic OR gate 212. A first input of the logic OR gate 212 is electrically connected to the output SCP_SAT of the first comparator 204. A second input of the logic OR gate 212 is electrically connected to the output SCP_SNS of the second comparator 206. When the output SCP_SAT of the first comparator 204 and / or the output SCP_SNS of the second comparator 206 becomes high, the output “SCP” of the logic OR gate 212 becomes high.

[0044] When the output SCP of the logic OR gate 212 goes high, the gate signal “Gate” generated by the gate driver 126 included in the second die 104 is overridden so that when the output SCP of the logic OR gate goes high, the main GaN power transistor GaN in the GaN die 102 Power This allows the main GaN power transistor GaN to be safely turned off within the device’s tolerance time. Power , thus avoiding destructive failures. Figure 2 The gate driver 126 is omitted in order to provide a clearer view of the current sensing and short circuit detection circuit components.

[0045] In more detail, the GaN power transistor GaN included in the GaN die 102 Power The GaN power transistor can enter saturation during operation, which occurs more frequently at high temperatures for GIT devices. Power The drain voltage rises rapidly and eventually causes the diode device 114 to enter forward conduction, causing the current (I SW ) flows through the voltage protection device 116 and into the first resistor R1. This current causes a voltage drop across the first resistor R1, which is greater than the voltage drop across the second resistor R2. The voltage difference is detected by the operational amplifier 200 of the current sensing circuit 112 included in the second semiconductor die 104. In addition, when the voltage drop across the first resistor R1 is greater than the first reference voltage source 208, the output SCP_SAT of the first comparator 204 of the short circuit detection circuit 118 included in the second die 104 becomes high. This in turn causes the output SCP of the logic OR gate 212 of the short circuit detection circuit 118 to become high, thereby indicating that the main GaN power transistor GaN Power In response, the logic OR gate output SCP can be used to disable the main GaN power transistor GaN Power , to protect the device from excessive power dissipation.

[0046] When the main GaN power transistor GaN Power The drain current I POWER The second comparator 206 of the short circuit detection circuit 118 triggers at a lower drain current when slowly rising at room temperature and lower temperatures (DC case). Providing two comparators 204, 206 protects the main GaN power transistor GaN over the entire operating temperature range. Power and to the main GaN power transistor GaN Power Interconnects (such as bond wires) are protected from destructive failure.

[0047] Although the present disclosure is not limited in this regard, the following numbered examples demonstrate one or more aspects of the present disclosure.

[0048] Example 1. A power electronic device, comprising a first semiconductor die and a second semiconductor die, the first semiconductor die comprising: a first current sensing terminal; a second current sensing terminal; a main GaN (gallium nitride) power transistor; a first GaN current sensing transistor having a source electrically connected to the second current sensing terminal and a drain electrically connected to the drain of the main GaN power transistor; a second GaN current sensing transistor having a source electrically connected to the source of the main GaN power transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device electrically connecting the drain of the second GaN current sensing transistor to the first current sensing terminal; the second semiconductor die comprising a current sensing circuit and a short circuit detection circuit electrically connected to the first current sensing terminal and the second current sensing terminal of the first semiconductor die, wherein the short circuit detection circuit is configured to detect: when the drain current of the main GaN power transistor exceeds a predetermined value, and when the main GaN power transistor is in saturation.

[0049] Example 2. A power electronic device according to Example 1, wherein the short circuit detection circuit includes: a first comparator having a first input electrically connected to a first current sensing terminal of the first semiconductor die, and a second input electrically connected to a first reference voltage source; and a second comparator having a first input electrically connected to a second current sensing terminal of the first semiconductor die, and a second input electrically connected to a second reference voltage source, wherein the output of the first comparator indicates when the main GaN power transistor is in saturation, and wherein the output of the second comparator indicates when the drain current of the main GaN power transistor exceeds a predetermined value.

[0050] Example 3. A power electronic device according to Example 2, wherein the short circuit detection circuit further includes: a logic OR gate having a first input electrically connected to the output of the first comparator, and a second input electrically connected to the output of the second comparator, wherein when the output of the first comparator and / or the output of the second comparator becomes high, the output of the logic OR gate becomes high.

[0051] Example 4. A power electronic device according to Example 3, wherein the second semiconductor die further comprises: a gate driver configured to apply a gate signal to a gate terminal of the first semiconductor die, wherein the gate terminal of the first semiconductor die is electrically connected to the gates of: a main GaN power transistor, a first GaN current sensing transistor, a second GaN current sensing transistor, and a voltage protection device, wherein when the output of the logic OR gate becomes high, the gate signal is overridden such that when the output of the logic OR gate becomes high, the main GaN power transistor is forced to be turned off.

[0052] Example 5. The power electronic device of Example 4, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a gate injection transistor, and wherein the gate signal is a gate current injection signal.

[0053] Example 6. The power electronic device of Example 4, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a Schottky gate HEMT (high electron mobility transistor), and wherein the gate signal is a gate voltage signal.

[0054] Example 7. A power electronic device according to any one of Examples 2 to 6, further comprising: a first resistor electrically connecting a first current sensing terminal of the first semiconductor die to ground, so that a first input of the first comparator corresponds to a voltage across the first resistor; and a second resistor electrically connecting a second current sensing terminal of the first semiconductor die to ground, so that a first input of the second comparator corresponds to a voltage across the second resistor.

[0055] Example 8. A power electronic device according to any one of Examples 1 to 7, wherein the diode device is a GaN transistor having a drain electrically connected to the drain of the main GaN power transistor, a source electrically connected to the drain of the second GaN current sensing transistor, and a gate electrically connected to the drain of the GaN transistor.

[0056] Example 9. A power electronic device according to any one of Examples 1 to 7, wherein the diode device is a pn diode having an anode electrically connected to the drain of the main GaN power transistor, and a cathode electrically connected to the drain of the second GaN current sensing transistor.

[0057] Example 10. A power electronic device according to any one of Examples 1 to 9, wherein the diode device is in reverse conduction when the main GaN power transistor is turned on, wherein the diode device enters forward conduction when the main GaN power transistor enters saturation, and wherein when the diode device enters forward conduction, current flows from the diode device into the voltage protection device.

[0058] Example 11. A power electronic device according to any one of Examples 1 to 10, wherein the voltage protection device is a GaN transistor having a drain electrically connected to the drain of the second GaN current sensing transistor, a source electrically connected to the first current sensing terminal of the first semiconductor die, and a gate electrically connected to the gate terminal of the first semiconductor die, wherein the gate terminal of the first semiconductor die is also electrically connected to the gate of the main GaN power transistor and the gate of the first GaN current sensing transistor.

[0059] Example 12. A power electronic device according to any one of Examples 1 to 11, wherein the current sensing circuit includes: an operational amplifier having a first input electrically connected to a first current sensing terminal of a first semiconductor die, and a second input electrically connected to a second current sensing terminal of the first semiconductor die; and a current source circuit configured to output a current sensing signal based on the output of the operational amplifier, wherein the amplitude of the current sensing signal is generated to minimize the voltage difference across the first current sensing terminal and the second current sensing terminal of the first semiconductor die.

[0060] Example 13. A sensing method for a GaN (gallium nitride) die, the GaN die comprising: a main GaN power transistor; a first GaN current sensing transistor having a source electrically connected to a second current sensing terminal of the GaN die, and a drain electrically connected to the drain of the main GaN power transistor; a second GaN current sensing transistor having a source electrically connected to the source of the main GaN power transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device that connects the second GaN current sensing transistor to the drain of the main GaN power transistor. The drain of the sensing transistor is electrically connected to a first current sensing terminal of the GaN die, and the sensing method includes: sensing a scaled-down copy of the current flowing in the main GaN power transistor based on a voltage at the first current sensing terminal of the GaN die and a voltage at a second current sensing terminal of the GaN die; detecting when the main GaN power transistor is in saturation based on the voltage at the first current sensing terminal of the GaN die and a first reference voltage; and detecting when the drain current of the main GaN power transistor exceeds a predetermined value based on the voltage at the second current sensing terminal of the GaN die and the second reference voltage.

[0061] Example 14. A sensing method according to Example 13, wherein detecting when the main GaN power transistor is in saturation includes: inputting a voltage at a first current sensing terminal of the GaN die and a first reference voltage to a first comparator on a die separate from the GaN die; and outputting an indication of when the main GaN power transistor is in saturation via the first comparator, wherein detecting when the drain current of the main GaN power transistor exceeds a predetermined value includes: inputting a voltage at a second current sensing terminal of the GaN die and a second reference voltage to a second comparator located on the same die as the first comparator; and outputting an indication of when the drain current of the main GaN power transistor exceeds a predetermined value via the second comparator.

[0062] Example 15. The sensing method according to Example 14 further includes: inputting the output of the first comparator and the output of the second comparator to a logic OR gate located on the same die as the first comparator and the second comparator, wherein when the output of the first comparator and / or the output of the second comparator becomes high, the output of the logic OR gate becomes high.

[0063] Example 16. The sensing method according to Example 15 also includes: applying a gate signal to a gate terminal of a first semiconductor die, wherein the gate terminal of the first semiconductor die is electrically connected to the gates of: a main GaN power transistor, a first GaN current sensing transistor, a second GaN current sensing transistor, and a voltage protection device; and overriding the gate signal when the output of the logic OR gate becomes high, so that when the output of the logic OR gate becomes high, the main GaN power transistor is forced to be turned off.

[0064] Example 17. The sensing method of Example 16, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a gate injection transistor, and wherein the gate signal is a gate current injection signal.

[0065] Example 18. The sensing method of Example 16, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a Schottky gate HEMT (high electron mobility transistor), and wherein the gate signal is a gate voltage signal.

[0066] Terms such as "first", "second", etc. are used to describe various elements, regions, parts, etc., and are not intended to be limiting. Throughout the specification, the same terms refer to the same elements.

[0067] As used herein, the terms "having", "comprising", "including", "comprising", etc. are open terms indicating the presence of stated elements or features, but not excluding additional elements or features. Unless the context clearly indicates otherwise, the articles "a", "an", and "the" are intended to include the plural as well as the singular.

[0068] Unless otherwise expressly stated, the expression "and / or" should be interpreted as including all possible combinations of connections and separations. For example, the expression "A and / or B" should be interpreted as meaning only A, only B, or both A and B. Unless otherwise expressly stated, the expression "at least one of..." should be interpreted in the same manner as "and / or". For example, the expression "at least one of A and B" should be interpreted as meaning only A, only B, or both A and B.

[0069] It should be understood that the features of the various embodiments described herein may be combined with each other, unless specifically stated otherwise.

[0070] Although specific embodiments have been illustrated and described herein, it will be appreciated by those skilled in the art that various alternative and / or equivalent embodiments may replace the specific embodiments shown and described without departing from the scope of the present invention. The present application is intended to cover any adaptation or variation of the specific embodiments discussed herein. Therefore, the present invention is intended to be limited only by the claims and their equivalents.

Claims

1. A power electronic device, comprising: A first semiconductor die comprising: a first current sensing terminal; a second current sensing terminal; Main GaN (gallium nitride) power transistor; a first GaN current sense transistor having a source electrically connected to the second current sense terminal and a drain electrically connected to the drain of the main GaN power transistor; a second GaN current sensing transistor having a source electrically connected to the source of the main GaN power transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device electrically connecting the drain of the second GaN current sensing transistor to the first current sensing terminal; a second semiconductor die comprising a current sensing circuit and a short circuit detection circuit electrically connected to the first current sensing terminal and the second current sensing terminal of the first semiconductor die, wherein the short circuit detection circuit is configured to detect when a drain current of the main GaN power transistor exceeds a predetermined value and when the main GaN power transistor is in saturation.

2. The power electronic device according to claim 1, wherein the short circuit detection circuit comprises: a first comparator having a first input electrically connected to the first current sense terminal of the first semiconductor die, and a second input electrically connected to a first reference voltage source; as well as a second comparator having a first input electrically connected to the second current sensing terminal of the first semiconductor die and a second input electrically connected to a second reference voltage source, wherein the output of the first comparator indicates when the main GaN power transistor is in saturation, Wherein the output of the second comparator indicates when the drain current of the main GaN power transistor exceeds the predetermined value.

3. The power electronic device according to claim 2, wherein the short circuit detection circuit further comprises: a logic OR gate having a first input electrically connected to the output of the first comparator and a second input electrically connected to the output of the second comparator, When the output of the first comparator and / or the output of the second comparator becomes high, the output of the logic OR gate becomes high.

4. The power electronic device of claim 3, wherein the second semiconductor die further comprises: a gate driver configured to apply a gate signal to a gate terminal of the first semiconductor die, wherein the gate terminal of the first semiconductor die is electrically connected to the gates of: the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device, Wherein when the output of the logic OR gate becomes high, the gate signal is overridden, so that when the output of the logic OR gate becomes high, the main GaN power transistor is forced to be turned off.

5. The power electronic device of claim 4, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a gate injection transistor, and wherein the gate signal is a gate current injection signal.

6. The power electronic device of claim 4, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a Schottky gate HEMT (High Electron Mobility Transistor), and wherein the gate signal is a gate voltage signal.

7. The power electronic device according to claim 2, further comprising: a first resistor electrically connecting the first current sensing terminal of the first semiconductor die to ground such that a first input of the first comparator corresponds to a voltage across the first resistor; as well as A second resistor electrically connects the second current sensing terminal of the first semiconductor die to ground such that a first input of the second comparator corresponds to a voltage across the second resistor.

8. The power electronic device of claim 1 , wherein the diode device is a GaN transistor having a drain electrically connected to the drain of the main GaN power transistor, a source electrically connected to the drain of the second GaN current sense transistor, and a gate electrically connected to the drain of the GaN transistor.

9. The power electronic device of claim 1, wherein the diode device is a pn diode having an anode electrically connected to the drain of the main GaN power transistor, and a cathode electrically connected to the drain of the second GaN current sense transistor.

10. The power electronic device of claim 1, wherein the diode device is in reverse conduction when the main GaN power transistor is turned on, wherein the diode device enters forward conduction when the main GaN power transistor enters saturation, and wherein when the diode device enters forward conduction, current flows from the diode device into the voltage protection device.

11. The power electronic device of claim 1 , wherein the voltage protection device is a GaN transistor having a drain electrically connected to the drain of the second GaN current sensing transistor, a source electrically connected to the first current sensing terminal of the first semiconductor die, and a gate electrically connected to a gate terminal of the first semiconductor die, wherein the gate terminal of the first semiconductor die is also electrically connected to the gate of the main GaN power transistor and the gate of the first GaN current sensing transistor.

12. The power electronic device of claim 1 , wherein the current sensing circuit comprises: an operational amplifier having a first input electrically connected to the first current sense terminal of the first semiconductor die, and a second input electrically connected to the second current sense terminal of the first semiconductor die; as well as A current source circuit is configured to output a current sensing signal based on the output of the operational amplifier, wherein a magnitude of the current sensing signal is generated to minimize a voltage difference across the first current sensing terminal and the second current sensing terminal of the first semiconductor die.

13. A sensing method for a GaN (gallium nitride) die, the GaN die comprising: Main GaN power transistor; a first GaN current sense transistor having a source electrically connected to a second current sense terminal of the GaN die, and a drain electrically connected to a drain of the main GaN power transistor; a second GaN current sensing transistor having a source electrically connected to the source of the main GaN power transistor; a diode device electrically connected in series between the drain of the main GaN power transistor and the drain of the second GaN current sensing transistor; and a voltage protection device, electrically connecting the drain of the second GaN current sensing transistor to the first current sensing terminal of the GaN die, the sensing method comprising: sensing a scaled-down replica of a current flowing in the main GaN power transistor based on a voltage at the first current sensing terminal of the GaN die and a voltage at the second current sensing terminal of the GaN die; detecting when the main GaN power transistor is in saturation based on a voltage at the first current sense terminal of the GaN die and a first reference voltage; and Based on the voltage at the second current sense terminal of the GaN die and a second reference voltage, detecting when the drain current of the main GaN power transistor exceeds a predetermined value.

14. The sensing method according to claim 13, Wherein detecting when the main GaN power transistor is in saturation comprises: inputting a voltage at the first current sensing terminal of the GaN die and the first reference voltage to a first comparator on a die separate from the GaN die; as well as outputting, via the first comparator, an indication of when the main GaN power transistor is in saturation, Wherein detecting when the drain current of the main GaN power transistor exceeds the predetermined value comprises: inputting a voltage at the second current sensing terminal of the GaN die and the second reference voltage to a second comparator located on the same die as the first comparator; as well as An indication of when the drain current of the main GaN power transistor exceeds the predetermined value is output via the second comparator.

15. The sensing method according to claim 14, further comprising: inputting the output of the first comparator and the output of the second comparator to a logic OR gate located on the same die as the first comparator and the second comparator, When the output of the first comparator and / or the output of the second comparator becomes high, the output of the logic OR gate becomes high.

16. The sensing method according to claim 15, further comprising: applying a gate signal to a gate terminal of the first semiconductor die, wherein the gate terminal of the first semiconductor die is electrically connected to gates of: the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device; as well as The gate signal is overridden when the output of the logic OR gate goes high so that the main GaN power transistor is forced off when the output of the logic OR gate goes high.

17. The sensing method of claim 16, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a gate injection transistor, and wherein the gate signal is a gate current injection signal.

18. The sensing method of claim 16, wherein each of the main GaN power transistor, the first GaN current sensing transistor, the second GaN current sensing transistor, and the voltage protection device is a Schottky gate HEMT (High Electron Mobility Transistor), and wherein the gate signal is a gate voltage signal.

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