High-side driver circuit and low-side driver circuit of bridge circuit

Abstract

To provide a driver circuit capable of detecting the transition of output voltage.SOLUTION: A high-side gate driver 320 controls a gate voltage of a high-side transistor MH in response to a high-side control signal HCTRL. A first connection node N1 is connected to the other end of a first detection capacitor Cd1 with its one end grounded. A source rise transition detection circuit 330 generates a rise transition detection signal SrH related to the rise transition of an output voltage VOUT of a bridge circuit 110 on the basis of a current I1 flowing in a route from first line Ln1 to the first connection node N1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a driver circuit for a bridge circuit. [Background technology]

[0002] Half-bridge circuits, H-bridge circuits, and three-phase bridge circuits (hereinafter collectively referred to as bridge circuits) using power transistors are widely used in motor driver circuits, DC / DC converters, power conversion devices, and the like.

[0003] The bridge circuit has an upper arm provided between the input line IN and the output line OUT, and a lower arm provided between the output line OUT and a ground line. The upper arm includes a high-side transistor and a flywheel diode connected in parallel. The lower arm includes a low-side transistor and a flywheel diode connected in parallel.

[0004] The bridge circuit can switch between a high output state, where the high-side transistor is on and the low-side transistor is off, and a low output state, where the high-side transistor is off and the low-side transistor is on. In the high output state, the output line OUT carries the voltage V of the input line. IN The output voltage V is at substantially the same voltage level as OUT In the low output state, the output line OUT has an output voltage V that is substantially at the same voltage level as the ground line. OUT occurs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2022 / 259780

[0006] The output voltage V is used to control the high-side driver that drives the high-side transistor and the low-side driver that drives the low-side transistor. OUTThe input voltage V IN and the output voltage V OUT By monitoring the potential difference between the high-side and low-side transistors, the output voltage V OUT Conversely, the output voltage V OUT The output voltage may be detected to have transitioned to low by monitoring the potential difference between the low-side transistor and the ground voltage of 0V, i.e., the voltage across the low-side transistor.

[0007] However, the input voltage V IN In high voltage applications where the output voltage V OUT It is difficult to monitor directly.

[0008] [overview] The present disclosure has been made in view of the above-mentioned problems, and one exemplary purpose of an embodiment thereof is to provide a driver circuit capable of detecting a transition in an output voltage.

[0009] One aspect of the present disclosure relates to a high-side driver circuit that drives a high-side transistor that constitutes a bridge circuit together with a low-side transistor. The high-side driver circuit includes: a first line generating a high voltage to be applied to the gate of the high-side transistor; a second line connected to the output of the bridge circuit; a high-side gate driver that controls the gate voltage of the high-side transistor in response to a high-side control signal; a high-side control circuit that generates the high-side control signal; a first connection node that is to be connected to one end of a first detection capacitor whose other end is grounded; and a source-rise transition detection circuit that generates a rise transition detection signal associated with a rise transition of the output voltage of the bridge circuit based on a current flowing through a path from the first line to the first connection node when the bridge circuit operates in source mode.

[0010] Another aspect of the present disclosure relates to a low-side driver circuit that drives a low-side transistor that forms a bridge circuit together with a high-side transistor, the low-side driver circuit including: a fifth line generating a high voltage to be applied to the gate of the low-side transistor; a sixth line connected to ground; a low-side gate driver that controls the gate voltage of the low-side transistor in response to a low-side control signal; a low-side control circuit that generates the low-side control signal; a second connection node that is to be connected to one end of a second detection capacitor that is connected to a first line generating the high voltage to be applied to the high-side transistor; and a sync-rise transition detection circuit that generates a rise transition detection signal associated with a rise transition of the output voltage of the bridge circuit based on a current flowing through a path from the fifth line to the second connection node when the bridge circuit operates in a sink mode.

[0011] Any combination of the above components, or mutual substitution of components or expressions between methods, devices, systems, etc. are also valid aspects of the present invention. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a circuit diagram of a switching circuit according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the operation of the source rise transition detection circuit and the source fall transition detection circuit of FIG. [Figure 3] FIG. 3 is a circuit diagram of a source rise transition detection circuit and a source fall transition detection circuit according to the first embodiment. [Figure 4] FIG. 4 is a circuit diagram of a source rise transition detection circuit and a source fall transition detection circuit according to the second embodiment. [Figure 5] FIG. 5 is a circuit diagram of a synch rise transition detection circuit and a synch fall transition detection circuit according to the first embodiment. [Figure 6] FIG. 6 is a circuit diagram of a synch rise transition detection circuit and a synch fall transition detection circuit according to the second embodiment. [Figure 7] FIG. 7 is a circuit diagram of a switching circuit according to a third embodiment. [Figure 8] FIG. 8 is an operational waveform diagram of the switching circuit of FIG. [Figure 9] FIG. 9 is a circuit diagram of a motor drive device including a switching circuit according to an embodiment.

[0013] [Detailed explanation] (Outline of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0014] A high-side driver circuit according to one embodiment drives high-side transistors that constitute a bridge circuit together with low-side transistors. The high-side driver circuit includes: a first line generating a high voltage to be applied to the gates of the high-side transistors; a second line connected to the output of the bridge circuit; a high-side gate driver that controls the gate voltage of the high-side transistor in response to a high-side control signal; a high-side control circuit that generates the high-side control signal; a first connection node that is to be connected to one end of a first detection capacitor whose other end is grounded; and a source-rise transition detection circuit that generates a rise transition detection signal associated with a rise transition of the output voltage of the bridge circuit based on a current flowing through a path from the first line to the first connection node when the bridge circuit operates in source mode.

[0015] With this configuration, transitions in the output voltage can be detected by monitoring the current flowing into the first detection capacitor.

[0016] In one embodiment, the source-rise transition detection circuit may include a first transistor having a source connected to a first line and a gate and a drain connected to a first connection node, a second transistor having a source connected to the first line and a gate connected to the gate of the first transistor, a third line generating a voltage lower than that of the first line, and a first resistor connected between the drain of the second transistor and the third line. The rise transition detection signal may have a level according to a comparison result between the voltage drop of the first resistor and a first threshold voltage.

[0017] In one embodiment, the source-rise transition detection circuit may further include a third transistor having a source connected to a third line and a gate connected to the drain of the second transistor, and the rise transition detection signal may have a level corresponding to whether the third transistor is on or off.

[0018] In one embodiment, a leading edge of the rising transition detection signal may indicate the beginning of a rising transition, and a trailing edge of the rising transition detection signal may indicate the end of the rising transition.

[0019] In one embodiment, the source-rise transition detection circuit includes a first transistor having a source connected to a first line and a gate and a drain connected to a first connection node, a second transistor having a source connected to the first line and a gate connected to the gate of the first transistor, a third line generating a voltage lower than that of the first line, and a first capacitor connected between the drain of the second transistor and the third line, and the rise transition detection signal may be based on a comparison result between the voltage of the first capacitor and a first threshold voltage.

[0020] In one embodiment, the high-side driver circuit may further include a source fall transition detection circuit that generates a fall transition detection signal related to a fall transition of the output voltage of the bridge circuit based on a current flowing in a path from the first connection node to the second line when the bridge circuit operates in source mode.

[0021] With this configuration, transitions in the output voltage can be detected by monitoring the current flowing out of the first detection capacitor.

[0022] In one embodiment, the source fall transition detection circuit may include a fourth transistor having a source connected to the second line and a gate and a drain connected to the first connection node, a fifth transistor having a source connected to the second line and a gate connected to the gate of the fourth transistor, a fourth line generating a voltage higher than that of the second line, and a second resistor connected between the drain of the fifth transistor and the fourth line. The fall transition detection signal may be based on a comparison result between a voltage drop across the second resistor and a second threshold voltage.

[0023] In one embodiment, the source fall transition detection circuit may further include a sixth transistor having a source connected to the fourth line and a gate connected to the drain of the fifth transistor, and the fall transition detection signal may have a level corresponding to the on / off state of the sixth transistor.

[0024] In one embodiment, a leading edge of the fall transition detection signal indicates the beginning of the fall transition and a trailing edge of the fall transition detection signal indicates the end of the fall transition.

[0025] In one embodiment, the source fall transition detection circuit may include a fourth transistor having a source connected to the second line and a gate and a drain connected to the first connection node, a fifth transistor having a source connected to the second line and a gate connected to the gate of the fourth transistor, a fourth line generating a voltage higher than that of the second line, and a second capacitor connected between the drain of the fifth transistor and the fourth line. The fall transition detection signal may be based on a comparison result between the voltage of the second capacitor and a second threshold voltage.

[0026] In one embodiment, a pin may be connected to the first connection node and the first sensing capacitor may be external to the high-side driver circuit.

[0027] In one embodiment, the first sense capacitor may be integrated into the high-side driver circuit.

[0028] In one embodiment, the high-side gate driver is a current-driven type, and the high-side control circuit may vary the output current of the high-side gate driver in response to a change in the rise transition detection signal.

[0029] In one embodiment, the high-side control circuit may further include a high-side sensor that generates a high-side sense signal indicative of a comparison result between the gate-source voltage of the high-side transistor and the decision threshold voltage, and the high-side control circuit may change the output current of the high-side gate driver in response to a change in the high-side sense signal.

[0030] A low-side driver circuit according to one embodiment drives a low-side transistor that constitutes a bridge circuit together with a high-side transistor. The low-side driver circuit includes: a fifth line generating a high voltage to be applied to the gate of the low-side transistor; a sixth line connected to ground; a low-side gate driver that controls the gate voltage of the low-side transistor in response to a low-side control signal; a low-side control circuit that generates the low-side control signal; a second connection node to be connected to one end of a second detection capacitor that has the other end connected to a first line generating the high voltage to be applied to the high-side transistor; and a sync-rise transition detection circuit that generates a rise transition detection signal associated with a rise transition of the output voltage of the bridge circuit based on a current flowing through a path from the fifth line to the second connection node when the bridge circuit operates in sink mode.

[0031] With this configuration, transitions in the output voltage can be detected by monitoring the current flowing into the second detection capacitor.

[0032] In one embodiment, the sync rise transition detection circuit may include a seventh transistor having a source connected to the sixth line and a gate and a drain connected to the second connection node, an eighth transistor having a source connected to the sixth line and a gate connected to the gate of the seventh transistor, an eighth line generating a voltage higher than that of the sixth line, and a third resistor connected between the drain of the eighth transistor and the eighth line. The rise transition detection signal may be based on a comparison result between a voltage drop across the third resistor and a third threshold voltage.

[0033] In one embodiment, the sync rise transition detection circuit may further include a ninth transistor having a source connected to the sixth line and a gate connected to the drain of the eighth transistor, and the rise transition detection signal may have a level depending on whether the ninth transistor is on or off.

[0034] In one embodiment, a leading edge of the rising transition detection signal may indicate the beginning of a rising transition, and a trailing edge of the rising transition detection signal may indicate the end of the rising transition.

[0035] In one embodiment, the synchronise transition detection circuit may include a third capacitor instead of the third resistor.

[0036] In one embodiment, the low-side driver circuit may further include a sink fall transition detection circuit that generates a fall transition detection signal related to a fall transition of the output voltage of the bridge circuit based on a current flowing from the second connection node toward the sixth line when the bridge circuit operates in sink mode.

[0037] In one embodiment, the sink fall transition detection circuit may include a tenth transistor having a source connected to the fifth line and a gate and a drain connected to the second connection node, an eleventh transistor having a source connected to the fifth line and a gate connected to the gate of the tenth transistor, a seventh line generating a voltage lower than the fifth line, and a fourth resistor connected between the drain of the eleventh transistor and the seventh line. The sink fall transition detection signal may have a level according to a comparison result between the voltage drop across the fourth resistor and a fourth threshold voltage.

[0038] In one embodiment, the sink fall transition detection circuit further includes a twelfth transistor having a source connected to the fifth line and a gate connected to the drain of the eleventh transistor, and the fall transition detection signal may have a level corresponding to the on / off state of the twelfth transistor.

[0039] In one embodiment, a leading edge of the fall transition detection signal indicates the beginning of a rise transition and a trailing edge of the fall transition detection signal indicates the end of the rise transition.

[0040] In one embodiment, the sinkfall transition detection circuit may include a fourth capacitor instead of the fourth resistor.

[0041] In one embodiment, a pin may be connected to the second connection node and the second sensing capacitor may be external to the low-side driver circuit.

[0042] In one embodiment, the second sense capacitor may be integrated into the low-side driver circuit.

[0043] In one embodiment, the low-side gate driver is a current-driven type, and the low-side control circuit may change the output current of the low-side gate driver in response to a change in the rise transition detection signal.

[0044] In one embodiment, the low-side control circuit may further include a low-side sensor that generates a low-side sense signal indicative of a comparison result between the gate-source voltage of the low-side transistor and the decision threshold voltage, and the low-side control circuit may change the output current of the low-side gate driver in response to a change in the low-side sense signal.

[0045] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. Furthermore, the embodiments are merely examples and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0046] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection between them or that do not impair the function or effect achieved by their connection.

[0047] Similarly, "a state in which component C is provided between component A and component B" includes not only cases in which components A and C, or components B and C, are directly connected, but also cases in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or impair the functions or effects achieved by their combination.

[0048] The vertical and horizontal axes of the waveform diagrams and time charts referred to in this specification have been appropriately enlarged or reduced to facilitate understanding, and the waveforms shown have been simplified, exaggerated, or emphasized to facilitate understanding.

[0049] 1 is a circuit diagram of a switching circuit 100 according to an embodiment. The switching circuit 100 includes a bridge circuit 110 and a driver circuit 200. Although only the configuration of one phase of the switching circuit 100 is shown here, the switching circuit 100 may be a three-phase circuit or an H-bridge circuit.

[0050] The input line 102 is connected to the input voltage V IN The technology according to the present disclosure is provided by IN This is particularly useful in applications where the input voltage V IN It can also be used in applications with voltages of several tens of volts.

[0051] The bridge circuit 110 includes a high-side transistor MH connected between an input line (input terminal) 102 and an output line (output terminal) 104, and a low-side transistor ML connected between the output line 104 and a ground line 106. The high-side transistor MH and the low-side transistor ML are N-channel transistors. An operating mode in which current flows out from the bridge circuit 110 toward the load is called a source mode, and an operating mode in which current flows from the load toward the bridge circuit 110 is called a sink mode.

[0052] The driver circuit 200 controls the high-side transistor MH and the low-side transistor ML of the bridge circuit 110. The driver circuit 200 controls a high output state φ in which the high-side transistor MH is on and the low-side transistor ML is off. H , the high-side transistor MH is off and the low-side transistor ML is on in the low output state φ LThe bridge circuit 110 switches between two states: a high-impedance state φ in which both the high-side transistor MH and the low-side transistor ML are off; HZ In some cases, the high output state φ H The output voltage V OUT is the input voltage V IN The low output state φ L At this point, the output voltage V OUT takes on a voltage level substantially equal to the ground voltage (0V).

[0053] The driver circuit 200 includes a high-side driver circuit 300 and a low-side driver circuit 400. The high-side driver circuit 300 and the low-side driver circuit 400 may be separate integrated circuits (ICs), or may be integrated into a single IC.

[0054] First, the configuration of the high-side driver circuit 300 will be described.

[0055] The high-side driver circuit 300 includes a high-side control circuit 310, a high-side gate driver 320, a source-rise transition detection circuit 330, and a source-fall transition detection circuit 340.

[0056] The high-side gate driver 320 controls the gate voltage V of the high-side transistor MH in response to the high-side control signal HCTRL generated by the high-side control circuit 310. HG The high-side gate driver 320 may be a voltage-driven type or a current-driven type. When the high-side gate driver 320 turns on the high-side transistor MH based on the high-side control signal HCTRL, the high-side gate driver 320 controls the gate-source voltage V HGS from 0V to high voltage V H High voltage V H is the gate-source voltage of the NMOS transistor, V GS(th) It is a higher voltage.

[0057] The first line Ln1 is connected to the source voltage of the high-side transistor MH, i.e., the output voltage V of the bridge circuit 110. OUT Higher voltage V H A voltage V H_HS The high-side gate driver 320 is supplied with a voltage V H_HS is supplied, and when the high-side transistor MH is turned on, the gate voltage V G voltage V H_HS Increase to.

[0058] On the other hand, when the high-side gate driver 320 turns off the high-side transistor MH in response to the high-side control signal HCTRL, the gate-source voltage V HGS High voltage V H to 0V (or a negative voltage).

[0059] The high-side control circuit 310 generates a high-side control signal HCTRL that indicates the state of the high-side gate driver 320 in response to an input signal HIN.

[0060] The second line Ln2 is connected to the output of the bridge circuit 110. A first end of the first detection capacitor Cd1 is grounded, and a second end thereof is connected to the first connection node N1.

[0061] The source-rise transition detection circuit 330 detects the output voltage V of the bridge circuit 110 based on the current I1 that flows through the path 332 from the first line Ln1 to the first connection node N1 when the bridge circuit 110 operates in the source mode. OUT The rise transition detection signal Sr H The rise transition detection signal Sr H For example, the timing of the start of the rise transition, the timing of the end of the rise transition, or the output voltage V OUT crosses a predetermined level, or a combination thereof.

[0062] The source fall transition detection circuit 340 detects the output voltage V of the bridge circuit 110 based on the current I2 that flows through the path 342 from the first connection node N1 to the second line Ln when the bridge circuit 110 operates in the source mode. OUT The fall transition detection signal Sf associated with the fall transition of H The fall transition detection signal Sf H For example, the start timing of the fall transition, the end timing of the fall transition, and the output voltage V OUT crosses a predetermined level, or a combination thereof.

[0063] The above is the configuration of the high-side driver circuit 300. Next, the operation of the high-side driver circuit 300 will be described.

[0064] 2 is a diagram illustrating the operation of the source rise transition detection circuit 330 and the source fall transition detection circuit 340 in FIG. 1. The bridge circuit 110 is operating in source mode. Before time t0, the output voltage V OUT is 0V. At time t0, the low-side transistor ML turns off. At time t1, the high-side transistor MH turns on. After the high-side transistor MH turns on, the on-resistance of the high-side transistor MH decreases as the gate-source voltage increases, and as a result, the output voltage V OUT is the input voltage V IN (source-rise transition). The voltage V H_HS is the output voltage V OUT than V H is a voltage higher than the output voltage V OUT As a result, a charging current I1 flows from the first line Ln1 to the first detection capacitor Cd1 through the path 332. The current I1 is proportional to the output voltage V OUT continues to flow while the output voltage V OUT is the input voltage V IN When the voltage at the first connection node N1 reaches 1, the current stops flowing. C1is 0V to V IN +V H rises to.

[0065] The source-rise transition detection circuit 330 detects this charging current I1 and outputs a rise transition detection signal Sr H For example, a signal indicating the start of the flow of the charging current I1, that is, the start timing t1 of the rise transition, can be generated as the rise transition detection signal Sr H Alternatively, a signal indicating the timing at which the charging current I1 stops flowing, that is, the timing t2 at which the rise transition ends, may be output as the rise transition detection signal Sr. H Alternatively, the output voltage V may be set based on the charging current I1. OUT is an arbitrary set voltage V SET1 The signal indicating the timing t3 at which the signal crosses the rise transition detection signal Sr H It may also be possible to use the following.

[0066] When a command to turn off the high-side transistor MH is issued at time t4, the gate-source voltage of the high-side transistor MH decreases. As a result, the on-resistance of the high-side transistor MH increases over time, the voltage drop across the high-side transistor MH increases, and the output voltage V OUT At this time, the voltage of the second line Ln2 decreases toward 0V (source fall transition). OUT Therefore, the charge stored in the first detection capacitor Cd1 is discharged toward the second line Ln2, and a discharge current I2 flows. The voltage at the first connection node N1, that is, the voltage V of the first detection capacitor Cd1, C1 is V IN +V H to 0V.

[0067] The source fall transition detection circuit 340 detects this discharge current I2 and outputs a fall transition detection signal Sf H For example, a signal indicating the start of the discharge current I2, that is, the start timing t5 of the fall transition, can be generated as a fall transition detection signal Sf HAlternatively, a signal indicating the timing at which the discharge current I2 stops flowing, that is, the end timing t6 of the fall transition, may be set as the rise transition detection signal Sr H Alternatively, the output voltage V may be set based on the discharge current I2. OUT is an arbitrary set voltage V SET2 The signal indicating the timing t7 at which the signal crosses the fall transition detection signal Sr L It may also be possible to use the following.

[0068] At time t5, the high-side transistor MH is turned off, and at time t6, the low-side transistor ML is turned on.

[0069] Next, the configuration of the low-side driver circuit 400 will be described.

[0070] The low-side driver circuit 400 includes a low-side control circuit 410, a low-side gate driver 420, a sink-rise transition detection circuit 430, and a sink-fall transition detection circuit 440.

[0071] The low-side gate driver 420 controls the gate voltage V of the low-side transistor ML in response to the low-side control signal LCTRL generated by the low-side control circuit 410. LG The low-side gate driver 420 may be a voltage-driven type or a current-driven type. When the low-side gate driver 420 turns on the low-side transistor ML in response to the low-side control signal LCTRL, the low-side gate driver 420 controls the gate-source voltage V LGS from 0V to high voltage V H High voltage V H is the gate-source voltage of the NMOS transistor, V GS(th) It is a higher voltage.

[0072] The fifth line Ln5 is connected to a high voltage V H A voltage V H_LS The low-side gate driver 420 is supplied with a voltage V H_LSis supplied, and when the low-side transistor ML is turned on, the gate voltage V G voltage V H_LS Increase to.

[0073] On the other hand, when the low-side gate driver 420 turns off the low-side transistor ML in response to the low-side control signal LCTRL, the gate-source voltage V LGS High voltage V H to 0V (or negative voltage).

[0074] The low-side control circuit 410 generates a low-side control signal LCTRL that indicates the state of the low-side gate driver 420 in response to an input signal LIN.

[0075] The sixth line Ln6 is grounded. A first end of the second detection capacitor Cd2 is connected to the first line Ln1, and a second end of the second detection capacitor Cd2 is connected to the second connection node N2.

[0076] The sink-rise transition detection circuit 430 detects the output voltage V of the bridge circuit 110 based on the current I3 that flows through the path 432 from the second connection node N2 to the sixth line Ln6 when the bridge circuit 110 operates in the sink mode. OUT The rise transition detection signal Sr L The rise transition detection signal Sr L For example, the timing of the start of the rise transition, the timing of the end of the rise transition, or the output voltage V OUT crosses a predetermined level, or a combination thereof.

[0077] The sink fall transition detection circuit 440 detects the output voltage V of the bridge circuit 110 based on the current I4 that flows through the path 442 from the fifth line Ln5 to the second connection node N2 when the bridge circuit 110 operates in the sink mode. OUT The fall transition detection signal Sf associated with the fall transition of L The fall transition detection signal SfL For example, the start timing of the fall transition, the end timing of the fall transition, and the output voltage V OUT crosses a predetermined level, or a combination thereof.

[0078] The above is the configuration of the low-side driver circuit 400. The sink-rise transition detection circuit 430 and sink-fall transition detection circuit 440 operate in the same manner as the source-rise transition detection circuit 330 and source-fall transition detection circuit 340, and detect the output voltage V OUT The transition can be detected.

[0079] Next, an example of the configuration of the source rise transition detection circuit 330 and the source fall transition detection circuit 340 on the high-side driver circuit 300 side will be described.

[0080] FIG. 3 is a circuit diagram of a source rise transition detection circuit 330A and a source fall transition detection circuit 340A according to the first embodiment.

[0081] The source-rise transition detection circuit 330A detects the charging current I1 at a predetermined threshold current I TH1 Compared with, I1>I TH1 When the rise transition detection signal Sr H is set to a predetermined level (for example, a low level) indicating that a rise transition is occurring. H The leading edge indicates the start timing of the rising transition, and the trailing edge indicates the end timing of the rising transition.

[0082] The source-rise transition detection circuit 330A includes a first transistor MP1, a second transistor MP2, a third transistor MN3, a first resistor R1, a first switch SW1, and a first current source CS1.

[0083] The first transistor MP1 is a P-type transistor, with its source connected to the first line Ln1 and its gate and drain connected to the first connection node N1 via the first switch SW1. The first transistor MP1 and the first switch SW1 form the charging path 332 in FIG. 1. The first switch SW1 is turned on during a period when a rise transition may occur and turned off during a period when a rise transition does not occur.

[0084] The second transistor MP2 has a source connected to the first line Ln1 and a gate connected to the gate of the first transistor MP1. The first transistor MP1 and the second transistor MP2 form a current mirror circuit. A current I1' proportional to the charging current I1 flowing through the first transistor MP1 flows through the second transistor MP2.

[0085] The third line Ln3 generates a voltage that is lower by a predetermined voltage (for example, 5V) than the first line Ln1.

[0086] The first resistor R1 is connected between the drain of the second transistor MP2 and the third line Ln3. A voltage drop V proportional to the current I1′ is generated across the first resistor R1. R1 occurs.

[0087] The source-rise transition detection circuit 330A detects the voltage drop V across the first resistor R1. R1 and the first threshold voltage V TH1 The rise transition detection signal Sr has a level according to the comparison result of H The third transistor MN3 and the first current source CS1 form a voltage comparison means. The source of the third transistor MN3 is connected to the third line Ln3, and the gate is connected to the drain of the second transistor MP2. That is, a voltage drop V across the first resistor R1 is generated between the gate and source of the third transistor MN3. R1 The first current source CS1 is connected to the drain of the third transistor MN3.

[0088] The threshold voltage of the third transistor MN3 is V GS(th) Then, V R1 >VGS(th) When the third transistor MN3 is turned on, the rise transition detection signal Sr H is at a low level indicating that a transition is in progress.

[0089] Instead of the first current source CS1 and the third transistor MN3, a voltage comparator or other comparison means may be used.

[0090] The source fall transition detection circuit 340A detects the discharge current I2 by a predetermined threshold current I TH2 Compared with, I2>I TH2 When the fall transition detection signal Sf H is set to a predetermined level (for example, a high level) indicating that a fall transition is in progress. H The leading edge indicates the start timing of the fall transition, and the trailing edge indicates the end timing of the fall transition.

[0091] The source fall transition detection circuit 340A includes a fourth transistor MN4, a fifth transistor MN5, a sixth transistor MP6, a second resistor R2, a second switch SW2, and a second current source CS2.

[0092] The fourth transistor MN4 is an N-type transistor, with its source connected to the second line Ln2 and its gate and drain connected to the first connection node N1 via the second switch SW2. The fourth transistor MN4 and the second switch SW2 form the discharge path 342 in FIG. 1. The second switch SW2 is turned on during a period when a fall transition may occur and turned off during a period when a fall transition will not occur.

[0093] The fifth transistor MN5 has a source connected to the second line Ln2 and a gate connected to the gate of the fourth transistor MN4. The fourth transistor MN4 and the fifth transistor MN5 form a current mirror circuit. A current I2' proportional to the discharge current I2 flowing through the fourth transistor MN4 flows through the fifth transistor MN5.

[0094] The fourth line Ln4 generates a voltage that is higher by a predetermined voltage (for example, 5V) than the second line Ln2.

[0095] The second resistor R2 is connected between the drain of the fifth transistor MN5 and the fourth line Ln4. A voltage drop V R2 occurs.

[0096] The source fall transition detection circuit 340A detects the voltage drop V across the second resistor R2. R1 and the second threshold voltage V TH2 A fall transition detection signal Sf having a level according to the comparison result H The sixth transistor MP6 and the second current source CS2 form a voltage comparison means. The source of the sixth transistor MP6 is connected to the fourth line Ln4, and the gate is connected to the drain of the fifth transistor MN5. The first current source CS1 is connected to the drain of the sixth transistor MP6. That is, a voltage drop V across the second resistor R2 is generated between the gate and source of the sixth transistor MP6. R2 The second current source CS2 is connected to the drain of the sixth transistor MP6.

[0097] The threshold voltage of the sixth transistor MP6 is V GS(th) Then, V R2 >V GS(th) At this time, the sixth transistor MP6 is turned on, and the fall transition detection signal Sf H is at a high level indicating that a transition is in progress.

[0098] Instead of the second current source CS2 and the sixth transistor MP6, a voltage comparator or other comparison means may be used.

[0099] FIG. 4 is a circuit diagram of a source rise transition detection circuit 330B and a source fall transition detection circuit 340B according to the second embodiment.

[0100] The source-rise transition detection circuit 330B integrates the charging current I1, compares the integrated value with a threshold value, and outputs a rise transition detection signal SrH Generate.

[0101] The source-rise transition detection circuit 330B includes a first capacitor C1 instead of the first resistor R1 in FIG. 2. During the source-rise transition, a current I1' proportional to the charging current I1 flows through the first capacitor C1, and the first capacitor C1 is charged. In other words, the voltage of the first capacitor C1 represents the integral value of the charging current I1. This integral value is used as the threshold voltage V TH1 During the rise transition, the output voltage V OUT is the threshold voltage V TH1 The timing at which the voltage of the first capacitor C1 crosses any voltage level according to the voltage level can be detected. A voltage comparator may be used instead of the third transistor MN3 and the first current source CS1. Also, multiple voltage comparators may be provided to compare the voltage of the first capacitor C1 with multiple threshold voltages.

[0102] The source fall transition detection circuit 340B similarly includes a second capacitor C2 instead of the second resistor R2 of FIG. 2. This configuration reduces the voltage drop of the output voltage V OUT is the threshold voltage V TH2 It is possible to detect the timing at which the voltage crosses any voltage level according to the voltage level.

[0103] Next, an example of the configuration of the synch-rise transition detection circuit 430 and the synch-fall transition detection circuit 440 on the low-side driver circuit 400 side will be described.

[0104] FIG. 5 is a circuit diagram of a sync rise transition detection circuit 430A and a sync fall transition detection circuit 440A according to the first embodiment.

[0105] The synchro-rise transition detection circuit 430A detects the current I3 at a predetermined threshold current I TH3 Compared with, I3>I TH3 When the rise transition detection signal Sr L is set to a predetermined level (for example, a low level) indicating that a rise transition is occurring. HThe leading edge indicates the start timing of the rising transition, and the trailing edge indicates the end timing of the rising transition.

[0106] The sync-rise transition detection circuit 430A includes a seventh transistor MN7, an eighth transistor MN8, a ninth transistor MP9, a third resistor R3, a third switch SW3, and a third current source CS3. The configuration of the sync-rise transition detection circuit 430A is the same as that of the source-fall transition detection circuit 340A in FIG. 3. The sync-rise transition detection circuit 430A generates a rise transition detection signal Sr that is at a high level during a rise transition. L can be generated.

[0107] The sinkfall transition detection circuit 440A detects the current I4 at a predetermined threshold current I TH4 Compared with, I4>I TH4 When the fall transition detection signal Sf L is set to a predetermined level (for example, a high level) indicating that a fall transition is in progress. L The leading edge indicates the start timing of the fall transition, and the trailing edge indicates the end timing of the fall transition.

[0108] The sinkfall transition detection circuit 440A includes a tenth transistor MP10, an eleventh transistor MP11, a twelfth transistor MN12, a fourth resistor R4, a fourth switch SW4, and a fourth current source CS4. The configuration of the sinkfall transition detection circuit 440A is similar to that of the source-rise transition detection circuit 330A in FIG.

[0109] FIG. 6 is a circuit diagram of a sync rise transition detection circuit 430B and a sync fall transition detection circuit 440B according to the second embodiment.

[0110] The sync rise transition detection circuit 430B integrates the current I3, compares the integrated value with a threshold value, and outputs a rise transition detection signal Sr according to the comparison result. L Generate.

[0111] The synchronous rise transition detection circuit 430B includes a third capacitor C3 instead of the third resistor R3 in FIG. 5. During the rise transition, a current I3' proportional to the current I3 flows through the third capacitor C3, and the third capacitor C3 is charged. In other words, the voltage of the third capacitor C3 indicates the integral value of the current I3. This integral value is used as the threshold voltage V TH3 During the rise transition, the output voltage V OUT is the threshold voltage V TH3 The timing at which the voltage across the third capacitor C3 crosses any voltage level according to the voltage level can be detected. A voltage comparator may be used instead of the ninth transistor MP9 and the third current source CS3. Also, multiple voltage comparators may be provided to compare the voltage across the third capacitor C3 with multiple threshold voltages.

[0112] Similarly, the sink fall transition detection circuit 440B includes a fourth capacitor C4 instead of the fourth resistor R4 of FIG. 5. With this configuration, during a sink fall transition, the output voltage V OUT is the threshold voltage V TH4 It is possible to detect the timing at which the voltage crosses any voltage level according to the voltage level.

[0113] 7 is a circuit diagram of a switching circuit 100C according to a third embodiment. In the third embodiment, a high-side driver circuit 300C and a low-side driver circuit 400C are separate ICs. The first detection capacitor Cd1 and the second detection capacitor Cd2 are provided outside the ICs. The high-side driver circuit 300C has a pin CD1 connected to a first connection node N1, and the first detection capacitor Cd1 is connected between the pin CD1 and ground. The low-side driver circuit 400C has a pin CD2 connected to the second connection node N2, and a second detection capacitor Cd2 is connected between the pin CD2 and the first line Ln1.

[0114] The high-side driver circuit 300C includes a high-side sensor 350. The high-side sensor 350 detects the gate-source voltage V of the high-side transistor MH. HGSThe high-side sense signal HSNS is generated by comparing the rise transition detection signal Sr H and the fall transition detection signal Sf H At the same time, the signal is supplied to the high-side control circuit 310.

[0115] Furthermore, an on-fix switch 360 and an off-fix switch 362 are connected to the gate of the high-side transistor MH.

[0116] The high-side gate driver 320 is a current-driven type, and supplies a drive current I ON By sourcing the gate-source voltage V HGS The drive current I OFF By sinking the gate-source voltage V HGS The high-side gate driver 320 includes a source current source 322 and a sink current source 324. The source current source 322 and the sink current source 324 are variable current sources, and generate a drive current I ON ,I OFF It is possible to switch between multiple levels.

[0117] The high-side control circuit 310 generates a high-side sense signal HSNS and a rise transition detection signal Sr H and the fall transition detection signal Sf H The drive current I generated by the source current source 322 or the sink current source 324 is ON ,I OFF The amount of the voltage is changed and the states of the switches 360 and 362 are changed.

[0118] The low-side driver circuit 400C includes a low-side sensor 450. The low-side sensor 450 detects the gate-source voltage V of the low-side transistor ML. LGS is compared with a decision threshold and a low-side sense signal LSNS is generated indicative of the comparison result.

[0119] The low-side sense signal LSNS is the rise transition detection signal Sr L and the fall transition detection signal Sf L At the same time, the signal is supplied to the low-side control circuit 410.

[0120] Furthermore, an on-fix switch 460 and an off-fix switch 462 are connected to the gate of the low-side transistor ML.

[0121] The low-side gate driver 420 is a current-driven type, and supplies a drive current I ON By sourcing the gate-source voltage V LGS The drive current I OFF By sinking the gate-source voltage V LGS The low-side gate driver 420 includes a source current source 422 and a sink current source 424. The source current source 422 and the sink current source 424 are variable current sources, and generate a drive current I ON ,I OFF It is possible to switch between multiple levels.

[0122] The low-side control circuit 410 generates a low-side sense signal LSNS and a rise transition detection signal Sr H and the fall transition detection signal Sf H The drive current I generated by the source current source 422 or the sink current source 424 is ON ,I OFF The amount of the voltage is changed and the states of the switches 460 and 462 are changed.

[0123] The above is the configuration of the switching circuit 100C. Next, the operation of the switching circuit 100C will be described.

[0124] 8 is an operational waveform diagram of the switching circuit 100C of FIG. 7. Here, we will explain the rise transition in source mode, in which the output current flows toward the load. This rise transition is realized by the turn-on operation of the high-side transistor MH by the high-side driver circuit 300C.

[0125] At time t0, the source current source 322 is enabled. Initially, the drive current I ON is supplied to the gate of the high-side transistor MH. This causes the gate-source voltage V HGS At time t1, the gate-source voltage V HGS When the drive current I exceeds the decision threshold of the high-side sensor 350, the high-side sense signal HSNS is asserted. ON is switched to a second current amount I2, which is less than the first current amount I1.

[0126] At time t2, the output voltage V OUT When the rising transition begins, the rising transition detection signal Sr H In response, the drive current I ON The current amount is switched to the third current amount I3. The third current amount I3 is greater than the first current amount I1. At time t3, the output voltage V OUT is the input voltage V IN When it rises to the vicinity, the rise transition detection signal Sr H In response to this negation, the on-fixing switch 360 is turned on, and the high-side transistor MH is fixed to the full on state.

[0127] The fall transition in the source mode can be similarly realized by the high-side driver circuit 300C turning off the high-side transistor MH. Specifically, the drive current I generated by the sink current source 324 OFF However, the high-side sense signal HSNS and the fall transition detection signal Sf H is controlled according to

[0128] The rise transition in the sink mode can be realized by the low-side driver circuit 400C turning off the low-side transistor ML. Specifically, the drive current I generated by the sink current source 424 OFF The low-side sense signal LSNS and the rise transition detection signal Sr Lis controlled according to

[0129] The fall transition in the sink mode can be realized by the low-side driver circuit 400C turning on the low-side transistor ML. Specifically, the drive current I generated by the source current source 422 ON The low-side sense signal LSNS and the fall transition detection signal Sf L is controlled according to

[0130] Next, we will explain the uses of the switching circuit 100. The switching circuit 100 can be suitably used in a motor driver circuit.

[0131] 9 is a circuit diagram of a motor driving device 500 including a switching circuit 100 according to an embodiment. The motor driving device 500 drives a three-phase motor 502, which is a load, and controls the rotation state.

[0132] Motor driving device 500 includes a bridge circuit 110 and a driver circuit 600. Bridge circuit 110 is a three-phase inverter and has U-phase, V-phase, and W-phase legs, and each phase leg has an upper arm and a lower arm.

[0133] The driver circuit 600 includes high-side driver circuits 300U to 300W, low-side driver circuits 400U to 400W, and a control circuit 610. The control circuit 610 includes a feedback circuit that performs feedback control so that the state of the three-phase motor 502 approaches a target state, and generates control signals that indicate the states of the six arms that make up the bridge circuit 110.

[0134] Although a three-phase motor is used as an example here, a single-phase motor may also be used, in which case the bridge circuit 110 becomes an H-bridge circuit.

[0135] Next, applications of the motor drive device 500 will be described. The motor drive device 500 can be used to drive motors in electric vehicles, hybrid vehicles, and the like. Alternatively, the motor drive device 500 can be used to control the spindle motor of a hard disk, or the lens drive motor of an imaging device. Alternatively, it can be used to drive the head drive motor of a printer, or the paper feed motor.

[0136] The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components and the respective treatment processes, and that such modifications are also within the scope of the present disclosure and the present invention. Such modifications will be described below.

[0137] (Variation 1) In the embodiment, the bridge circuit 110 is configured with discrete components, but this is not limiting, and the bridge circuit 110 may be integrated into the driver circuit 200.

[0138] (Variation 2) The high-side transistor MH and the low-side transistor ML may be configured by an IGBT (Insulated Gate Bipolar Transistor).

[0139] (Variation 3) The application of the switching circuit 100 is not limited to the motor drive device 500. For example, the switching circuit 100 can be suitably used in switching regulators (DC / DC converters), various power conversion devices (inverters and converters), inverters for lighting discharge lamps, digital audio amplifiers, etc. Therefore, the switching circuit 100 can be used in consumer devices including electronic devices and home appliances, automobiles and on-board components, industrial vehicles and industrial machinery.

[0140] The embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are possible to the embodiments without departing from the spirit of the present invention as defined in the claims.

[0141] (Addendum) The present specification discloses the following techniques.

[0142] (Item 1) A high-side driver circuit that drives a high-side transistor that configures a bridge circuit together with a low-side transistor, a first line on which a high voltage to be applied to the gate of the high-side transistor is generated; a second line connected to the output of the bridge circuit; a high-side gate driver that controls a gate voltage of the high-side transistor in response to a high-side control signal; a high-side control circuit that generates the high-side control signal; a first connection node to be connected to one end of a first detection capacitor whose other end is grounded; a source-rise transition detection circuit that generates a rise transition detection signal related to a rise transition of an output voltage of the bridge circuit based on a current flowing through a path from the first line to the first connection node when the bridge circuit operates in a source mode; 1. A high-side driver circuit comprising:

[0143] (Item 2) The source-rise transition detection circuit includes: a first transistor having a source connected to the first line and a gate and a drain connected to the first connection node; a second transistor having a source connected to the first line and a gate connected to the gate of the first transistor; a third line generating a voltage lower than that of the first line; a first resistor connected between the drain of the second transistor and the third line; Including, 2. The high-side driver circuit according to item 1, wherein the rise transition detection signal has a level according to a comparison result between the voltage drop across the first resistor and a first threshold voltage.

[0144] (Item 3) The source-rise transition detection circuit includes: Item 3. The high-side driver circuit of item 2 further includes a third transistor having a source connected to the third line and a gate connected to the drain of the second transistor, and the rise transition detection signal has a level corresponding to the on / off state of the third transistor.

[0145] (Item 4) The leading edge of the rise transition detection signal detects the start point of the rise transition as follows: 4. The high-side driver circuit of item 3, wherein a trailing edge of the rising transition detection signal indicates an end of the rising transition.

[0146] (Item 5) The source-rise transition detection circuit includes: a first transistor having a source connected to the first line and a gate and a drain connected to the first connection node; a second transistor having a source connected to the first line and a gate connected to the gate of the first transistor; a third line generating a voltage lower than that of the first line; a first capacitor connected between the drain of the second transistor and the third line; 2. The high-side driver circuit of claim 1, wherein the rise transition detection signal is responsive to a comparison result between the voltage of the first capacitor and a first threshold voltage.

[0147] (Item 6) 6. The high-side driver circuit according to any one of items 1 to 5, further comprising a source fall transition detection circuit that generates a fall transition detection signal associated with a fall transition of the output voltage of the bridge circuit based on a current flowing in a path from the first connection node to the second line when the bridge circuit operates in a source mode.

[0148] (Item 7) The source fall transition detection circuit a fourth transistor having a source connected to the second line and a gate and a drain connected to the first connection node; a fifth transistor having a source connected to the second line and a gate connected to the gate of the fourth transistor; a fourth line generating a voltage higher than that of the second line; a second resistor connected between the drain of the fifth transistor and the fourth line; Including, 7. The high-side driver circuit of claim 6, wherein the fall transition detection signal is responsive to a comparison result between the voltage drop across the second resistor and a second threshold voltage.

[0149] (Item 8) The source fall transition detection circuit Item 8. The high-side driver circuit of item 7, further comprising a sixth transistor having a source connected to the fourth line and a gate connected to the drain of the fifth transistor, wherein the fall transition detection signal has a level corresponding to the on / off state of the sixth transistor.

[0150] (Item 9) The leading edge of the fall transition detection signal indicates the start of the fall transition. 9. The high-side driver circuit of claim 8, wherein a trailing edge of the fall transition detection signal indicates an end of the fall transition.

[0151] (Item 10) The source fall transition detection circuit a fourth transistor having a source connected to the second line and a gate and a drain connected to the first connection node; a fifth transistor having a source connected to the second line and a gate connected to the gate of the fourth transistor; a fourth line generating a voltage higher than that of the second line; a second capacitor connected between the drain of the fifth transistor and the fourth line; Including, 7. The high-side driver circuit of claim 6, wherein the fall transition detection signal is dependent on a comparison result between the voltage of the second capacitor and a second threshold voltage.

[0152] (Item 11) 11. The high-side driver circuit of any one of items 1 to 10, wherein a pin is connected to the first connection node, and the first detection capacitor is external to the high-side driver circuit.

[0153] (Item 12) 11. The high-side driver circuit of any one of items 1 to 10, wherein the first sense capacitor is integrated into the high-side driver circuit.

[0154] (Item 13) the high-side gate driver is a current-driven type; 13. The high-side driver circuit of any one of items 1 to 12, wherein the high-side control circuit changes an output current of the high-side gate driver in response to a change in the rise transition detection signal.

[0155] (Item 14) a high-side sensor that generates a high-side sense signal indicating a result of comparison between the gate-source voltage of the high-side transistor and a determination threshold voltage; 14. The high-side driver circuit of any one of items 1 to 13, wherein the high-side control circuit changes an output current of the high-side gate driver in response to a change in the high-side sense signal.

[0156] (Item 15) A low-side driver circuit that drives a low-side transistor that configures a bridge circuit together with a high-side transistor, a fifth line on which a high voltage to be applied to the gate of the low-side transistor is generated; A sixth line that is grounded; a low-side gate driver that controls a gate voltage of the low-side transistor in response to a low-side control signal; a low-side control circuit that generates the low-side control signal; a second connection node to be connected to one end of a second detection capacitor, the other end of the second detection capacitor being connected to a first line on which a high voltage to be applied to the high-side transistor is generated; a sink rise transition detection circuit that generates a rise transition detection signal related to a rise transition of an output voltage of the bridge circuit based on a current flowing through a path from the fifth line to the second connection node when the bridge circuit operates in a sink mode; 1. A low-side driver circuit comprising:

[0157] (Item 16) The sync rise transition detection circuit a seventh transistor having a source connected to the sixth line and a gate and a drain connected to the second connection node; an eighth transistor having a source connected to the sixth line and a gate connected to a gate of the seventh transistor; an eighth line generating a voltage higher than that of the sixth line; a third resistor connected between the drain of the eighth transistor and the eighth line; Including, Item 16. The low-side driver circuit of item 15, wherein the rise transition detection signal is responsive to a comparison result between a voltage drop across the third resistor and a third threshold voltage.

[0158] (Item 17) The sync rise transition detection circuit Item 17. The low-side driver circuit of item 16 further includes a ninth transistor having a source connected to the sixth line and a gate connected to the drain of the eighth transistor, and the rise transition detection signal has a level corresponding to the on / off state of the ninth transistor.

[0159] (Item 18) The leading edge of the rise transition detection signal detects the start point of the rise transition as follows: 18. The low-side driver circuit of item 16 or 17, wherein a trailing edge of the rising transition detection signal indicates an end of the rising transition.

[0160] (Item 19) 17. The low-side driver circuit of claim 16, wherein the synchronizing transition detection circuit includes a third capacitor instead of the third resistor.

[0161] (Item 20) 20. The low-side driver circuit of any one of items 15 to 19, further comprising a sink fall transition detection circuit that generates a fall transition detection signal related to a fall transition of the output voltage of the bridge circuit based on a current flowing from the second connection node to the sixth line when the bridge circuit operates in a sink mode.

[0162] (Item 21) The sinkfall transition detection circuit a tenth transistor having a source connected to the fifth line and a gate and a drain connected to the second connection node; an eleventh transistor having a source connected to the fifth line and a gate connected to a gate of the tenth transistor; a seventh line generating a voltage lower than that of the fifth line; a fourth resistor connected between the drain of the eleventh transistor and the seventh line; Including, 21. The low-side driver circuit of item 20, wherein the fall transition detection signal has a level according to a comparison result between the voltage drop across the fourth resistor and a fourth threshold voltage.

[0163] (Item 22) The sinkfall transition detection circuit Item 22. The low-side driver circuit of item 21, further comprising a twelfth transistor having a source connected to the fifth line and a gate connected to the drain of the eleventh transistor, wherein the fall transition detection signal has a level corresponding to the on / off state of the twelfth transistor.

[0164] (Item 23) a leading edge of the fall transition detection signal indicates the start point of the rise transition; 23. The low-side driver circuit of item 21 or 22, wherein a trailing edge of the fall transition detection signal indicates the end of the rise transition.

[0165] (Item 24) 24. The low-side driver circuit of any one of items 21 to 23, wherein the sink fall transition detection circuit includes a fourth capacitor instead of the fourth resistor.

[0166] (Item 25) 25. The low-side driver circuit of any one of items 15 to 24, wherein a pin is connected to the second connection node, and the second detection capacitor is external to the low-side driver circuit.

[0167] (Item 26) 25. The low-side driver circuit of any of items 15 to 24, wherein the second sense capacitor is integrated into the low-side driver circuit.

[0168] (Item 27) the low-side gate driver is a current-driven type; 27. The low-side driver circuit of any one of items 15 to 26, wherein the low-side control circuit changes the output current of the low-side gate driver in response to a change in the rise transition detection signal.

[0169] (Item 28) a low-side sensor that generates a low-side sense signal indicating a comparison result between the gate-source voltage of the low-side transistor and a determination threshold voltage; 28. The low-side driver circuit of any of items 15 to 27, wherein the low-side control circuit changes the output current of the low-side gate driver in response to a change in the low-side sense signal. [Explanation of symbols]

[0170] 100 Switching Circuit 102 input lines 104 output lines 106 Ground Line 110 Bridge Circuit MH high-side transistor ML low-side transistor 200 Drive Circuit 300 High-side driver circuit 310 High-side control circuit 320 High Side Gate Driver 322 Source Current Source 324 Sink Current Source 330 Source-Rise Transition Detection Circuit 340 Source Fall Transition Detection Circuit 350 High Side Sensor 400 Low-side driver circuit 410 Low-side control circuit 420 Low-Side Gate Driver 422 Source Current Source 424 Sink Current Source 430 Synchro Transition Detection Circuit 440 Sinkfall Transition Detection Circuit 450 Low Side Sensor MP1 First transistor MP2 Second transistor MN3 Third transistor MN4 Fourth transistor MN5 fifth transistor MP6 6th transistor MN7 7th transistor MN8 8th transistor MP9 9th transistor MP10 10th transistor MP11 11th transistor MN12 12th transistor SW1 First switch SW2 Second switch SW3 Third switch SW4 4th switch R1 First resistor R2 2nd resistor R3 3rd resistor R4 4th resistor Cd1 First detection capacitor Cd2 Second detection capacitor C1 First capacitor C2 Second capacitor C3 Third capacitor C4 Fourth capacitor Ln1 1st line Ln2 Second line Ln3 Third Line Ln4 4th line Ln5 5th line Ln6 6th Line

Claims

1. A high-side driver circuit that drives a high-side transistor that configures a bridge circuit together with a low-side transistor, a first line on which a high voltage to be applied to the gate of the high-side transistor is generated; a second line connected to the output of the bridge circuit; a high-side gate driver that controls a gate voltage of the high-side transistor in response to a high-side control signal; a high-side control circuit that generates the high-side control signal; a first connection node to be connected to one end of a first detection capacitor whose other end is grounded; a source-rise transition detection circuit that generates a rise transition detection signal related to a rise transition of an output voltage of the bridge circuit based on a current flowing through a path from the first line to the first connection node when the bridge circuit operates in a source mode; 1. A high-side driver circuit comprising:

2. The source-rise transition detection circuit includes: a first transistor having a source connected to the first line and a gate and a drain connected to the first connection node; a second transistor having a source connected to the first line and a gate connected to the gate of the first transistor; a third line generating a voltage lower than that of the first line; a first resistor connected between the drain of the second transistor and the third line; Including, 2. The high-side driver circuit according to claim 1, wherein the rise transition detection signal has a level according to a result of comparing a voltage drop across the first resistor with a first threshold voltage.

3. The source-rise transition detection circuit includes:

3. The high-side driver circuit according to claim 2, further comprising a third transistor having a source connected to the third line and a gate connected to the drain of the second transistor, wherein the rise transition detection signal has a level corresponding to whether the third transistor is on or off.

4. The source-rise transition detection circuit includes: a first transistor having a source connected to the first line and a gate and a drain connected to the first connection node; a second transistor having a source connected to the first line and a gate connected to the gate of the first transistor; a third line generating a voltage lower than that of the first line; a first capacitor connected between the drain of the second transistor and the third line; 2. The high-side driver circuit of claim 1, wherein the rise transition detection signal is responsive to a comparison result between the voltage of the first capacitor and a first threshold voltage.

5. 5. The high-side driver circuit of claim 1, further comprising a source fall transition detection circuit that generates a fall transition detection signal associated with a fall transition of an output voltage in the source mode of the bridge circuit based on a current flowing in a path from the first connection node to the second line when the bridge circuit operates in the source mode.

6. The source fall transition detection circuit a fourth transistor having a source connected to the second line and a gate and a drain connected to the first connection node; a fifth transistor having a source connected to the second line and a gate connected to the gate of the fourth transistor; a fourth line generating a voltage higher than that of the second line; a second resistor connected between the drain of the fifth transistor and the fourth line; Including, 6. The high-side driver circuit of claim 5, wherein the fall transition detection signal is responsive to a comparison result between a voltage drop across the second resistor and a second threshold voltage.

7. The source fall transition detection circuit 7. The high-side driver circuit of claim 6, further comprising a sixth transistor having a source connected to the fourth line and a gate connected to the drain of the fifth transistor, wherein the fall transition detection signal has a level corresponding to whether the sixth transistor is on or off.

8. The source fall transition detection circuit a fourth transistor having a source connected to the second line and a gate and a drain connected to the first connection node; a fifth transistor having a source connected to the second line and a gate connected to the gate of the fourth transistor; a fourth line generating a voltage higher than that of the second line; a second capacitor connected between the drain of the fifth transistor and the fourth line; Including, 6. The high-side driver circuit of claim 5, wherein the fall transition detection signal is responsive to a comparison result between the voltage of the second capacitor and a second threshold voltage.

9. the high-side gate driver is a current-driven type; 5. The high-side driver circuit according to claim 1, wherein the high-side control circuit changes an output current of the high-side gate driver in response to a change in the rise transition detection signal.

10. a high-side sensor that generates a high-side sense signal indicating a result of comparison between the gate-source voltage of the high-side transistor and a determination threshold voltage; 5. The high-side driver circuit according to claim 1, wherein the high-side control circuit changes an output current of the high-side gate driver in response to a change in the high-side sense signal.

11. A low-side driver circuit that drives a low-side transistor that configures a bridge circuit together with a high-side transistor, a fifth line on which a high voltage to be applied to the gate of the low-side transistor is generated; a sixth line that is grounded; a low-side gate driver that controls a gate voltage of the low-side transistor in response to a low-side control signal; a low-side control circuit that generates the low-side control signal; a second connection node to be connected to one end of a second detection capacitor, the other end of the second detection capacitor being connected to a first line on which a high voltage to be applied to the high-side transistor is generated; a sink rise transition detection circuit that generates a rise transition detection signal related to a rise transition of an output voltage of the bridge circuit based on a current flowing through a path from the fifth line to the second connection node when the bridge circuit operates in a sink mode; 1. A low-side driver circuit comprising:

12. The sync rise transition detection circuit a seventh transistor having a source connected to the sixth line and a gate and a drain connected to the second connection node; an eighth transistor having a source connected to the sixth line and a gate connected to the gate of the seventh transistor; an eighth line generating a voltage higher than that of the sixth line; a third resistor connected between the drain of the eighth transistor and the eighth line; Including, 12. The low-side driver circuit of claim 11, wherein the rise transition detection signal is responsive to a comparison result between a voltage drop across the third resistor and a third threshold voltage.

13. The sync rise transition detection circuit 13. The low-side driver circuit of claim 12, further comprising a ninth transistor having a source connected to the sixth line and a gate connected to the drain of the eighth transistor, wherein the rise transition detection signal has a level corresponding to whether the ninth transistor is on or off.

14. 13. The low-side driver circuit of claim 12, wherein the synchronise transition detection circuit includes a third capacitor instead of the third resistor.

15. 15. The low-side driver circuit of claim 11, further comprising a sink fall transition detection circuit that generates a fall transition detection signal related to a fall transition of an output voltage of the bridge circuit based on a current flowing from the second connection node to the sixth line when the bridge circuit operates in a sink mode.

16. The sinkfall transition detection circuit a tenth transistor having a source connected to the fifth line and a gate and a drain connected to the second connection node; an eleventh transistor having a source connected to the fifth line and a gate connected to a gate of the tenth transistor; a seventh line generating a voltage lower than that of the fifth line; a fourth resistor connected between the drain of the eleventh transistor and the seventh line; Including, 16. The low-side driver circuit according to claim 15, wherein the fall transition detection signal has a level according to a result of comparing a voltage drop across the fourth resistor with a fourth threshold voltage.

17. The sinkfall transition detection circuit 16. The low-side driver circuit of claim 15, further comprising a twelfth transistor having a source connected to the fifth line and a gate connected to the drain of the eleventh transistor, wherein the fall transition detection signal has a level corresponding to whether the twelfth transistor is on or off.

18. 17. The low-side driver circuit of claim 16, wherein the sinkfall transition detection circuit includes a fourth capacitor instead of the fourth resistor.

19. the low-side gate driver is a current-driven type; 15. The low-side driver circuit according to claim 11, wherein the low-side control circuit changes an output current of the low-side gate driver in response to a change in the rise transition detection signal.

20. a low-side sensor that generates a low-side sense signal indicating a comparison result between the gate-source voltage of the low-side transistor and a determination threshold voltage; 15. The low-side driver circuit of claim 11, wherein the low-side control circuit changes an output current of the low-side gate driver in response to a change in the low-side sense signal.

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