Electronic circuit

Abstract

The invention relates to an electronic circuit comprising: • a first switch having a first pin, a second pin, and a third pin, and a second switch having a first pin, a second pin, and a third pin; • wherein the first pin is coupled to a positive voltage source, the second pin is coupled to a first connection point, and the third pin is coupled to a second connection point; • wherein the first pin is coupled to the second connection point, the second pin is designed to receive a control signal, and the third pin is coupled to an electrical reference.

Description

Electronic circuit DESCRIPTION [Technical field]

[0001] The present invention relates to an electronic circuit such as a device for controlling a switching structure connected to an inductor.

[0002] The present invention finds preferential but non-limiting applications in the automotive field.

[0003] The present invention can be implemented, for example, in an electronic circuit incorporating a switching structure such as an H-transistor bridge or a half-H-transistor bridge, or any structure based on a switching cell with an inductive element connected across the midpoint. [State of the prior art]

[0004] It is common for those skilled in the art to control at least one switch such as a transistor in a load control circuit.

[0005] Figure 1 illustrates an example of such a control circuit 10. Said control circuit 10 comprises a first switch C10, a second switch C20. Each switch can be a MOS transistor type transistor for “metal-oxide-semiconductor” or a MOSFET transistor for “Metal oxide semiconductor field effect transistor”.

[0006] The first switch C10 has a first pin C10B1 , a second pin C10B2 and a third pin C10B3. The pins correspond to either a gate, a source or a drain of said transistor. The second switch C20 has a first pin C20B1 , a second pin C20B2 and a third pin C20B3.

[0007] In this case and as illustrated in Figure 1, the first pin C10B1 is coupled to a positive voltage. Said positive voltage is for example a voltage of 600 Volts. The second pin C10B2 is coupled to a first connection point C100. Finally, the third pin C10B3 is coupled to a second connection point C200.

[0008] The first pin C20B1 is coupled to the second connection point C200. The second pin C20B2 is adapted to receive a control signal not shown. Finally, the third pin C20B3 is coupled to an electrical reference, for example an electrical ground.

[0009] Finally, an inductance L is coupled to the second connection point C200.

[0010] The first connection point C100 is also coupled to a first resistor R1 which itself is coupled to a terminal D10B1 of a circuit of the control circuit type D10. Finally, a second resistor R2 is coupled on the one hand to the first connection point C100 and on the other hand to the second connection point C200.

[0011] The control circuit type circuit D10 further comprises a second terminal D10B2 coupled to the second connection point C200 and also coupled to a first capacitor C1. Said first capacitor C1 comprises a first capacitor terminal C1 B1 coupled to the second connection point C200 and a second capacitor terminal C1 B2 coupled to a third terminal D10B3 of said control circuit type circuit D10. Finally, a diode D1 is coupled to the first capacitor C1. The anode of said diode D1 is coupled to a first voltage V1.

[0012] In Figure 1, the transistors are symbolically represented with a diode DC10 and DC20 representative of the body diode of said transistors. This representation is common for those skilled in the art.

[0013] There are different ways to control such a circuit and thus control a current flowing in the inductance L.

[0014] For example, the first way is to control the first switch C10 located on the high-voltage side (it could later also be called the first switch C10 high-side) with an actuation mechanism called "bootstrap".

[0015] Depending on the technology used to design the C10 and C20 switches, the DC10 and DC20 body diodes may not be present. For example, when transistors use IGBT (insulated-gate bipolar transistor) or GaN technology, there is often no body diode. With such technologies, the C10 and C20 switches cannot behave correctly during deadtimes. This is because the current from the inductive source cannot loop back through any path.

[0016] It is more common for IGBTs and GaN components to require negative control either due to their intrinsic nature or to have a margin that will robustify the control relative to their natural threshold. The generation of a negative voltage creates complexity in the circuitry causing bulk or increase in the size of the printed circuit board (PCB) and also an additional cost linked to the use of a multitude of additional components.

[0017] There is therefore a real need to be able to generate a negative control voltage for the first switch in a simple and inexpensive way while guaranteeing correct behavior during deadtimes. [Statement of the invention] The invention relates to an electronic circuit comprising: • a first switch comprising a first pin, a second pin and a third pin, and a second switch comprising a first pin, a second pin and a third pin, • the first pin being coupled to a positive voltage source, the second pin being coupled to a first connection point, the third pin being coupled to a second connection point, • the first pin being coupled to the second connection point, the second pin being adapted to receive a control signal, the third pin being coupled to an electrical reference, • a load coupled to the second connection point, • the first connection point also being coupled to a first resistor itself coupled to a terminal of a circuit, • a second resistor being coupled on the one hand to the first connection point and on the other hand to the second connection point, • the circuit further comprising a second terminal coupled to a third connection point, said third connection point being further coupled on the one hand to a first capacitor and on the other hand to a first diode, • the first capacitor comprising a first capacitor terminal coupled to the third connection point and a second capacitor terminal coupled to the second connection point, • the first diode being coupled to the first capacitor in a passing position, an anode of said first diode being coupled to a first voltage, said electronic circuit being characterized in that: • at the first switch an electronic circuit is coupled and is adapted to allow the electronic circuit to operate with a “boot-strap” type actuation mode and in that the first switch does not include an internal diode or body diode. In an exemplary embodiment, the circuit comprises a first terminal, a second terminal and a third terminal; the first terminal is adapted to be coupled to the positive voltage source of the electronic circuit, the first terminal is further adapted to be coupled to the first pin of the first switch, the second terminal is adapted to be coupled to a third terminal of the control circuit, the third terminal is adapted to be coupled to the second connection point, said electronic circuit comprises a second diode, a third diode and a second capacitor;the second diode has a first diode terminal coupled to the first terminal, the second diode also has a second diode terminal coupled to the second terminal, the second capacitor has a first capacitor terminal coupled to the second terminal and a second capacitor terminal coupled to the third terminal, the third diode has a first diode terminal coupled to the second terminal and a second diode terminal coupled to the third terminal.; For example, the first switch is an IGBT technology transistor. In another example, the first switch is a MOSGaN technology transistor. [Description of the drawings]

[0018] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This description is purely illustrative and must be read in conjunction with the appended drawings in which:

[0019] [Fig. 1] Figure 1 is a symbolic representation of a prior art control circuit,

[0020] [Fig. 2] Figure 2 is a symbolic representation of a control circuit according to the invention. [Description of embodiments]

[0021] The invention cleverly proposes to use an additional circuit B coupled to a first switch C 1000 not having a body diode. The first switch C1000 is for example an IGBT type transistor, or a GaN type transistor. The first switch C1000 is used as a high-side transistor.

[0022] As shown in Figure 2, the electronic circuit 1000 according to the invention comprises the first switch C1000, a second switch C2000. Each switch is an IGBT type transistor, or a GaN type transistor.

[0023] Alternatively, any switch not having a body diode can be used in the context of the invention.

[0024] The first switch C1000 has a first pin C1000B1, a second pin C1000B2 and a third pin C1000B3. The pins correspond to either a gate, a source or a drain of said transistor. The second switch C2000 has a first pin C2000B1, a second pin C2000B2 and a third pin C2000B3. The pins correspond to either a gate, a source or a drain of said transistor.

[0025] In this case and as illustrated in Figure 2, the first pin C1000B1 is coupled to a positive voltage Vdd. Said positive voltage is for example a voltage of 600 Volts. The second pin C1000B2 is coupled to a first connection point MC100. Finally, the third pin C1000B3 is coupled to a second connection point MC200.

[0026] The first pin C2000B1 is coupled to the second connection point MC200. The second pin C2000B2 is adapted to receive a control signal not shown. Finally, the third pin C2000B3 is coupled to an electrical reference such as ground.

[0027] Finally, an inductance L is coupled to the second connection point MC200. This inductance is considered an inductive source within the scope of the invention.

[0028] The first connection point MC100 is also coupled to a first resistor R1 which itself is coupled to a terminal D10B1 of a circuit of the control circuit type D10. Finally, a second resistor R2 is coupled on the one hand to the first connection point MC100 and on the other hand to the second connection point MC200.

[0029] The control circuit type circuit D10 further comprises a second terminal D10B2 which is coupled to a third connection point MC300.

[0030] The third connection point MC300 is coupled on the one hand to a first capacitor C1 and on the other hand to a first diode D1. Said first capacitor C1 comprises a first capacitor terminal C1 B1 coupled to the third connection point MC300 and a second capacitor terminal C1 B2 coupled to the second connection point MC200.

[0031] Finally, a first diode D1 is coupled to the first capacitor 01. The anode of said first diode D1 D1A1 is coupled to a first voltage V1.

[0032] The invention proposes to position at the level of the first switch C1000 the electronic circuit B adapted to allow the electronic circuit 1000 to operate with a negative bootstrap type actuation mode.

[0033] The electronic circuit B according to the invention comprises a first terminal B1, a second terminal B2 and a third terminal B3. The first terminal B1 is adapted to be coupled to the positive voltage of the electronic circuit 1000. Furthermore, it is adapted to be coupled to the first pin C100B1 of the first switch C100. The second terminal B2 is adapted to be coupled to a third terminal D10B3 of the control circuit type circuit D10. Finally, the third terminal B3 is adapted to be coupled to the second connection point MC200.

[0034] The electronic circuit B advantageously comprises a second diode BD2, a third diode BD3 and a second capacitor BC2.

[0035] Advantageously, the electronic circuit B allows the first switch C1000 to operate similarly to a transistor having a body diode. To do this, the second diode BD2 comprises a first diode terminal BD2_1 coupled to the first terminal B1 of the electronic circuit B. It also comprises a second diode terminal BD2_2 coupled to the second terminal B2 of the electronic circuit B. Furthermore, the second capacitor BC2 comprises a first capacitor terminal BC2_1 coupled to the second terminal B2 and a second capacitor terminal BC2_2 coupled to the third terminal B3. Finally, the third diode BD3 comprises a first diode terminal BD3_1 coupled to the second terminal B2 and a second diode terminal BD3_2 coupled to the third terminal B3.

[0036] Thanks to the invention and the use of the third diode BD2, it is possible to have the first switch C1000 which operates as a transistor having a body diode after the charging of the bootstrap capacitor. Indeed, during the "deadtime", thanks to the current of the source L in the diode BD2 and in the second capacitor BC2, the voltage across the second capacitor BC2 increases until it reaches the zener voltage of the third diode BD3 (which is a Zener diode). For example, the zener voltage is 5V. Thus, once the voltage across the third diode BD3 is reached, the current passes through the latter allowing the charging of BC2 to stop at a stabilized voltage value and to end the deadtime phase as with a conventional body diode of the chosen voltage.

[0037] The invention can advantageously be used in the case of transistor gate blocking control in the presence of noise. Thanks to the invention, the control of such a transistor is robustified despite the noise.

Claims

Claims

1. Electronic circuit (1000) comprising: • a first switch (C1000) comprising a first pin (C1000B1), a second pin (C1000B2) and a third pin (C1000B3), and a second switch (C2000) comprising a first pin (C2000B1), a second pin (C2000B2) and a third pin (C2000B3), • the first pin (C1000B1) being coupled to a positive voltage, the second pin (C1000B2) being coupled to a first connection point (MC100), the third pin (C1000B3) being coupled to a second connection point (MC200), • the first pin (C2000B1) being coupled to the second connection point (MC200), the second pin (C2000B2) being adapted to receive a control signal, the third pin (C2000B3) being coupled to an electrical reference, • an inductance (L) coupled to the second connection point (MC200), • the first connection point (MC100) also being coupled to a first resistor (R1) itself coupled to a terminal (D10B1) of a circuit (D10), • a second resistor (R2) being coupled on the one hand to the first connection point (MC100) and on the other hand to the second connection point (MC200), • the circuit (D10) further comprising a second terminal (D10B2) coupled to a third connection point (MC300), said third connection point (MC300) being further coupled on the one hand to a first capacitor (C1) and on the other hand to a first diode (D1), • the first capacitor (C1) comprising a first capacitor terminal (C1 B1) coupled to the third connection point (MC300) and a second capacitor terminal (C1 B2) coupled to the second connection point (MC200), • the first diode (D1) being coupled to the first capacitor (C1) in a passing position, an anode of said first diode (D1A1) being coupled to a first voltage (V1), said electronic circuit (1000) being characterized in that: • at the first switch (C1000) an electronic circuit (B) is coupled and is adapted to allow the electronic circuit (1000) to operate with a “negative boot-strap” type actuation mode and in that the first switch (C1000) does not comprise an internal diode or a body diode, and wherein, the electronic circuit (B) comprises a first terminal (B1), a second terminal (B2) and a third terminal (B3); the first terminal (B1) is adapted to be coupled to the positive voltage of the electronic circuit (1000), the first terminal (B1) is further adapted to be coupled to the first pin (C100B1) of the first switch (C100), the second terminal (B2) is adapted to be coupled to a third terminal (D10B3) of the control circuit (D10), the third terminal (B3) is adapted to be coupled to the second connection point (MC200), said electronic circuit (B) comprises a second diode (BD2), a third diode (BD3) and a second capacitor (BC2);the second diode (BD2) has a first diode terminal (BD2_1) coupled to the first terminal (B1), the second diode (BD2) also has a second diode terminal (BD2_2) coupled to the second terminal (B2), the second capacitor (BC2) has a first capacitor terminal (BC2_1) coupled to the second terminal (B2) and a second capacitor terminal (BC2_2) coupled to the third terminal (B3), the third diode (BD3) has a first diode terminal (BD3_1) coupled to the second terminal (B2) and a second diode terminal (BD3_2) coupled to the third terminal (B3).;

2. Electronic circuit (1000) according to claim 1, wherein the first switch (C1000) is an IGBT technology transistor.

3. Electronic circuit (1000) according to claim 1 or claim 2, wherein the first switch (C1000) is a GaN technology transistor.

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