Electrostatic discharge circuit of bootstrap circuit and integrated circuit

Abstract

The invention relates to an electrostatic discharge circuit of a bootstrap circuit and an integrated circuit. The circuit comprises a high-voltage operation area and a common voltage end, wherein the high-voltage operation area comprises a bootstrap capacitor bias end, a switch switching end and a bootstrap diode. The electrostatic discharge circuit is composed of a first electrostatic discharge circuit, a second electrostatic discharge circuit, a trigger circuit and a switching circuit. During normal operation, high voltage in the peripheral area of the bootstrap diode enables the trigger circuit to output a disable signal, and the switching circuit is cut off. When electrostatic discharge occurs, the peripheral region of the bootstrap diode has no charge, and the trigger circuit outputs an enable signal to switch on the switching circuit, so that an electrostatic protection function is realized.

Description

TECHNICAL FIELD

[0001] The present invention relates to a technology of electrostatic discharge, and in particular to an electrostatic discharge circuit of bootstrap circuit and integrated circuit. BACKGROUND

[0002] In prior art, bootstrap circuit is used for gate drive of high side device of bridge drive circuit, Figure 1 The circuit diagram of bootstrap circuit in prior art is shown. Please refer to Figure 1 Generally, the gate drive voltage of N-channel metal oxide semiconductor field effect transistor Ml, M2 needs to be 10V to 15V higher than the source voltage. When the high side N-channel metal oxide semiconductor field effect transistor Ml is turned on, the source voltage is equal to the voltage of external high voltage power supply (VB) due to the turn-on. However, if the gate voltage does not rise, the high side N-channel metal oxide semiconductor field effect transistor Ml will be turned off. Therefore, the power supply voltage requirement for the gate drive of the high side N-channel metal oxide semiconductor field effect transistor Ml is very high, which is equal to the voltage of external high voltage power supply (VB) plus the gate-to-source turn-on voltage of 10V to 15V. The bootstrap circuit structure is a voltage boosting charge pump composed of capacitor CB and diode Dl (a switch can be added).

[0003] Figure 2 The schematic diagram of electrostatic discharge protection circuit of power control integrated circuit in prior art is shown. Please refer to Figure 2 In the electrostatic discharge (ESD) protection circuit design of such power control integrated circuit, there is a set of electrostatic discharge components 201 between the switching node SW end and the high side voltage source node VB, and a set of electrostatic discharge components 202 between the switching node SW end and the low side ground node GND. At the same time, there is a set of electrostatic discharge clamp (ESD Pow

[0004] er clamp) components 203, 204 between the high side voltage source node VB and the low side ground node GND, and between the integrated circuit power supply voltage VCC and the low side ground node GND. When static electricity occurs at the switching node SW end, there is a positive static electricity acting on the SW end point and being discharged to GND. The discharge path of electrostatic discharge current can be path P1, through the parasitic diode structure of the high side N-channel metal oxide semiconductor field effect transistor Ml and the electrostatic discharge component 203 between the voltage source node VB and the ground node GND, to the ground node GND, or path P2, through the electrostatic discharge component 202 between the switching node SW end and the low side ground node GND, to the ground node GND.

[0005] In addition to the two discharge paths mentioned above, there is a potential discharge path P3 through the high-side N-channel metal oxide semiconductor field effect transistor Ml parasitic diode structure, the bootstrap diode Dl, and the electrostatic discharge component 204 between the power voltage path VCC and the ground node GND to the ground node GND. Since the bootstrap diode Dl is mainly in the charging function, the area does not need to be too large, and the increase in the component size will also cause the leakage to increase. Since the bootstrap diode Dl is small in size and poor in electrostatic discharge capability, it is designed to avoid becoming an electrostatic discharge path. However, the breakdown voltage of the electrostatic discharge component 203 between the voltage source node VB and the ground node GND and the breakdown voltage of the bootstrap diode Dl plus the breakdown voltage of the electrostatic discharge component 204 are very close, indicating that the trigger voltages of the two electrostatic discharge are very close, and therefore, the bootstrap diode Dl can be damaged due to conduction. SUMMARY

[0006] Embodiments of the present application provide an electrostatic discharge circuit of a bootstrap circuit and an integrated circuit to avoid the diode of the bootstrap circuit from becoming an electrostatic discharge path.

[0007] A preferred embodiment of the present application provides an electrostatic discharge circuit of a bootstrap circuit and an integrated circuit. The bootstrap circuit includes a high voltage operating region and a common voltage terminal. The high voltage operating region includes a bootstrap capacitor bias terminal, a switch switching terminal, and a bootstrap diode. The bootstrap diode includes an anode terminal, a cathode terminal, and a peripheral region. The anode terminal of the bootstrap diode is coupled to a power voltage terminal, and the cathode terminal of the bootstrap diode is coupled to the bootstrap capacitor bias terminal. The electrostatic discharge circuit includes a first electrostatic discharge circuit, a second electrostatic discharge circuit, a trigger circuit, and a switch circuit. The first electrostatic discharge circuit is coupled between the bootstrap capacitor bias terminal and the common voltage terminal. The second electrostatic discharge circuit is coupled between the switch switching terminal and the bootstrap capacitor bias terminal. The trigger circuit includes an input terminal and an output terminal. The input terminal of the trigger circuit is coupled to the peripheral region of the bootstrap diode. The switch circuit includes a control terminal, a first terminal, and a second terminal. The control terminal of the switch circuit is coupled to the output terminal of the trigger circuit, the first terminal of the switch circuit is coupled to the switch switching terminal, and the second terminal of the switch circuit is coupled to the common voltage terminal. When normally operating, the trigger circuit outputs a disable signal through the high voltage of the peripheral region of the bootstrap diode, so that the first terminal of the switch circuit and the second terminal of the switch circuit are cut off. When electrostatic discharge is performed, the peripheral region of the bootstrap diode is chargeless, the trigger circuit triggers an enable signal, and further controls the first terminal of the switch circuit and the second terminal of the switch circuit to be turned on.

[0008] In summary, the preferred embodiment of the present application provides an electrostatic discharge circuit for a bootstrap circuit and an integrated circuit using the same. The bootstrap circuit includes a high-voltage operating region, in which a bootstrap diode connects a power supply voltage terminal and a bootstrap capacitor bias terminal. The electrostatic discharge circuit is composed of multiple sub-circuits, including first and second electrostatic discharge circuits, a trigger circuit, and a switch circuit. These circuits work together ingeniously, maintaining the switch circuit in cutoff during normal operation and turning it on in the case of electrostatic discharge. The core advantage of the present application lies in its ability to effectively prevent the bootstrap diode from becoming a path for electrostatic discharge, thereby greatly improving the reliability and tolerance of the circuit. This design not only maintains efficient bootstrap function in normal working state, but also quickly responds to electrostatic discharge, protecting critical components from damage. This dual protection mechanism greatly extends the service life of the circuit, reduces the failure rate caused by electrostatic discharge, and thus reduces maintenance costs.

[0009] For a more complete understanding of the technology, means, and effects of the present application, reference is made to the following detailed description and accompanying drawings, in which: BRIEF DESCRIPTION OF DRAWINGS

[0010] The accompanying drawings provided herein are for further understanding of the present application by one of ordinary skill in the art and are incorporated in and constitute a part of the specification. The drawings illustrate exemplary embodiments of the present application and serve to explain the principles of the present application together with the specification.

[0011] Figure 1 A circuit diagram illustrating a bootstrap circuit in the prior art.

[0012] Figure 2 A schematic diagram illustrating an electrostatic discharge protection circuit of a power control integrated circuit in the prior art.

[0013] Figure 3 A circuit block diagram illustrating a touch device according to a preferred embodiment of the present application.

[0014] Figure 4 A circuit diagram illustrating an integrated circuit with an electrostatic discharge circuit having a bootstrap circuit according to a preferred embodiment of the present application.

[0015] Figure 5 A circuit diagram illustrating an integrated circuit with an electrostatic discharge circuit having a bootstrap circuit according to a preferred embodiment of the present application.

[0016] Figure 6 A circuit diagram illustrating an integrated circuit with an electrostatic discharge circuit having a bootstrap circuit according to a preferred embodiment of the present application.

[0017] Figure 7 FIG. 1 is a circuit diagram of an integrated circuit with an electrostatic discharge circuit having a bootstrap circuit, according to a preferred embodiment of the present application.

[0018] Reference Signs List:

[0019] M1, M2...N channel metal oxide semiconductor field effect transistor; CB...bootstrap capacitor; D1...diode; SW_N...switch node; VB_N...high side voltage source node; 201, 202, 203, 204...electrostatic discharge component; GND_N...low side ground node; P1, P2, P3: discharge path; VCC: integrated circuit power voltage; HVA...high voltage operation area; LVA...low voltage operation area; VB...bootstrap capacitor bias voltage terminal; SW...switch terminal; BD...bootstrap diode; GND...common voltage terminal; 301...peripheral area of bootstrap diode BD; 302...trigger circuit; 303...switching circuit; 401...P-type transistor; 402...N-type transistor; 403...N-type transistor; 501...N-type transistor; 502...resistor; 601...resistor; 701...transistor. DETAILED DESCRIPTION

[0020] Reference will now be made in detail to the exemplary embodiments of the present application, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the specification to refer to the same or like parts. In addition, exemplary embodiments are merely examples of implementing the design concept of the present application, and the following exemplary embodiments are not intended to limit the present application.

[0021] Figure 3 FIG. 1 is a circuit diagram of an integrated circuit with an electrostatic discharge circuit having a bootstrap circuit, according to a preferred embodiment of the present application. Figure 3 The integrated circuit includes a high voltage operation area HVA and a low voltage operation area LVA. The high voltage operation area HVA includes a bootstrap capacitor bias voltage terminal VB, a switch terminal SW, and a bootstrap diode BD. The low voltage operation area LVA only shows a common voltage terminal GND in this embodiment, however, actually the low voltage operation area LVA also includes other circuits, such as low side switch, low side electrostatic discharge circuit, etc., which are omitted from the drawing. In addition, in this embodiment, the bootstrap diode BD includes a peripheral area 301. Since the bootstrap diode BD is in the high voltage area, an isolated diode structure is used, having an anode electrode (Anode) and a cathode electrode (Cathode), and surrounded by a deep well, which is considered as isolation. This is the above-mentioned peripheral area 301.

[0022] In this embodiment, the ESD circuit includes a trigger circuit 302 and a switch circuit 303. The trigger circuit 302 includes an input terminal and an output terminal, wherein the input terminal of the trigger circuit 302 is coupled to the peripheral region 301 of the bootstrap diode BD. The control terminal of the switch circuit 303 is coupled to the output terminal of the trigger circuit 302, the first terminal of the switch circuit 303 is coupled to the switch terminal SW, and the second terminal of the switch circuit 303 is coupled to the common voltage terminal GND. When operating normally, the peripheral region 301 of the bootstrap diode BD is charged to a high voltage, and when the trigger circuit 302 receives the high voltage, the output terminal of the trigger circuit 302 controls the switch circuit 303 to close the circuit between the switch terminal SW and the common voltage terminal GND, so that the circuit is not conductive. The bootstrap capacitor CB coupled between the switch terminal SW and the bootstrap capacitor bias terminal VB is used to provide bootstrap bias voltage for high-side driving together with the bootstrap diode BD. The high voltage refers to a voltage greater than a preset value; the preset value is set according to actual needs, and the embodiment of the present application is not limited.

[0023] When the integrated circuit is not operating, at this time, the peripheral region 301 of the bootstrap diode BD has no charge, which is equivalent to that a low voltage is input to the input terminal of the trigger circuit 302. At this time, assuming that static electricity occurs at the switch terminal SW, the trigger circuit 302 is started, and the trigger circuit 302 controls the switch circuit 303 to be conductive, so that the switch circuit 303 makes the circuit between the switch terminal SW and the common voltage terminal GND conductive, and the static electricity is discharged from the switch circuit 303 to the grounding point of the common voltage terminal GND.

[0024] Figure 4 The circuit diagram of the integrated circuit with the ESD circuit with the bootstrap circuit according to a preferred embodiment of the present application is shown. Please refer to Figure 4 In this embodiment, the trigger circuit 302 of the ESD circuit is implemented by a P-type transistor 401 and an N-type transistor 402. In addition, the switch circuit 303 is implemented by an N-type transistor 403. When static electricity occurs at the switch terminal SW, since the gates of the P-type transistor 401 and the N-type transistor 402 are in a chargeless state, at this time, the static electricity is output as a high voltage through the inverter of the P-type transistor 401 and the N-type transistor 402, and the N-type transistor 403 is triggered (controlled) to be conductive, and the static electricity is discharged from the N-type transistor 403 to the grounding point of the common voltage terminal GND.

[0025] Figure 5 The circuit diagram of the integrated circuit with the ESD circuit with the bootstrap circuit according to a preferred embodiment of the present application is shown. Please refer to Figure 4 and Figure 5 In this embodiment, Figure 4The inverter composed of P-type transistor 401 and N-type transistor 402 is replaced by N-type transistor 501 and resistor 502. Since the operation is similar, it will not be described in detail here.

[0026] Figure 6 The diagram illustrates an integrated circuit with a bootstrap circuit for electrostatic discharge, representing a preferred embodiment of the present invention. Please refer to... Figure 3 as well as Figure 6 In this embodiment, relative to Figure 3 The cathode of the bootstrap diode BD is coupled to a resistor 601 to the peripheral region 301 of the bootstrap diode BD. Figure 7 The diagram illustrates an integrated circuit with a bootstrap circuit for electrostatic discharge, representing a preferred embodiment of the present invention. Please refer to... Figure 3 , Figure 6 as well as Figure 7 Similarly, a transistor 701 is coupled to the cathode of the bootstrap diode BD to the peripheral region 301 of the bootstrap diode BD. The aforementioned transistor can be used to isolate the cathode electrode and the isolation terminal of the bootstrap diode BD using a depletion-type metal-oxide-semiconductor field-effect transistor (depletion NMOS) or a junction field-effect transistor (JFET) to prevent electrostatic discharge damage.

[0027] In summary, this invention provides an innovative integrated design of a bootstrap circuit and an electrostatic discharge (ESD) circuit. The bootstrap circuit includes a high-voltage operating region, where a bootstrap diode is connected to the power supply voltage terminal and the bootstrap capacitor bias terminal. The ESD circuit consists of multiple sub-circuits, including first and second ESD circuits, a trigger circuit, and a switching circuit. These circuits work ingeniously together, keeping the switching circuit off during normal operation and turning it on during ESD. The core advantage of this invention lies in its ability to effectively prevent the bootstrap diode from becoming a path for ESD, thereby significantly improving the reliability and resilience of the circuit. This design not only maintains high-efficiency bootstrap functionality under normal operating conditions but also reacts quickly to ESD, protecting critical components from damage. This dual protection mechanism greatly extends the circuit's lifespan, reduces the failure rate caused by ESD, and thus lowers maintenance costs.

[0028] Furthermore, the design of this invention is highly adaptable and can be easily integrated into various electronic devices, providing a strong guarantee for improving the overall system's anti-static capability. Therefore, this invention not only solves the vulnerability of traditional bootstrap circuits to electrostatic discharge, but also opens up new avenues for the reliability and safety design of electronic products.

[0029] It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the claims.

Claims

1. An electrostatic discharge circuit for a bootstrap circuit, characterized in that, The bootstrap circuit includes: A high-voltage operating area, including: One bootstrap capacitor bias terminal; A switch switching terminal; and a bootstrap diode, including an anode, a cathode, and a peripheral region, wherein the anode of the bootstrap diode is coupled to a power supply voltage terminal, and the cathode of the bootstrap diode is coupled to the bias terminal of the bootstrap capacitor; and A total of voltage terminals are connected; and The electrostatic discharge circuit includes: A trigger circuit includes an input terminal and an output terminal, wherein the input terminal of the trigger circuit is coupled to the peripheral region of the bootstrap diode; A switching circuit includes a control terminal, a first terminal, and a second terminal, wherein the control terminal of the switching circuit is coupled to the output terminal of the trigger circuit, the first terminal of the switching circuit is coupled to the switching terminal, and the second terminal of the switching circuit is coupled to the common voltage terminal. During normal operation, the high voltage in the peripheral region of the bootstrap diode causes the trigger circuit to output a disabling signal, which cuts off the first terminal and the second terminal of the switching circuit. The high voltage refers to a voltage greater than a preset value. When electrostatic discharge occurs, the peripheral region of the bootstrap diode is free of charge, and the trigger circuit triggers an enable signal, further controlling the first terminal of the switching circuit to conduct with the second terminal of the switching circuit.

2. The electrostatic discharge circuit of the bootstrap circuit according to claim 1, characterized in that, The trigger circuit includes: A P-type transistor includes a gate, a first source-drain, and a second source-drain, wherein the gate of the P-type transistor is coupled to the peripheral region of the bootstrap diode, the first source-drain of the P-type transistor is coupled to the switching terminal, and the second source-drain of the P-type transistor is coupled to the control terminal of the switching circuit; and an N-type transistor includes a gate, a first source-drain, and a second source-drain, wherein the gate of the N-type transistor is coupled to the peripheral region of the bootstrap diode, the first source-drain of the N-type transistor is coupled to the second source-drain of the P-type transistor and the control terminal of the switching circuit, and the second source-drain of the N-type transistor is coupled to the common voltage terminal.

3. The electrostatic discharge circuit of the bootstrap circuit according to claim 1, characterized in that, The trigger circuit includes: An impedance circuit includes a first terminal and a second terminal, wherein the first terminal of the impedance circuit is coupled to the peripheral region of the bootstrap diode; and An N-type transistor includes a gate, a first source-drain, and a second source-drain, wherein the gate of the N-type transistor is coupled to the second terminal of the impedance circuit, the first source-drain of the N-type transistor is coupled to the control terminal of the switching circuit, and the second source-drain of the N-type transistor is coupled to the common voltage terminal.

4. The electrostatic discharge circuit of the bootstrap circuit according to claim 1, characterized in that, The switching circuit includes: An N-type transistor includes a gate, a first source-drain, and a second source-drain, wherein the gate of the N-type transistor is coupled to the output terminal of the trigger circuit, the first source-drain of the N-type transistor is coupled to the switching terminal, and the second source-drain of the N-type transistor is coupled to the common voltage terminal.

5. The electrostatic discharge circuit of the bootstrap circuit according to claim 1, characterized in that, The space between the bias terminal of the bootstrap capacitor and the cathode of the bootstrap diode includes: An isolation transistor includes a gate, a first source-drain, and a second source-drain, wherein the gate and the first source-drain of the isolation transistor are coupled to the cathode of the bootstrap diode, and the second source-drain of the isolation transistor is coupled to the bias terminal of the bootstrap capacitor.

6. The electrostatic discharge circuit of the bootstrap circuit according to claim 1, characterized in that, The space between the bias terminal of the bootstrap capacitor and the cathode of the bootstrap diode includes: A resistor includes a first terminal and a second terminal, wherein the first terminal of the resistor is coupled to the cathode of the bootstrap diode, and the second terminal of the resistor is coupled to the bias terminal of the bootstrap capacitor.

7. An integrated circuit, characterized in that, include: The bootstrap circuit as described in any one of claims 1 to 6; as well as The electrostatic discharge circuit as described in any one of claims 1 to 6.

8. The integrated circuit according to claim 7, characterized in that, The bootstrap capacitor bias terminal and the switch switching terminal are used to externally couple a bootstrap capacitor.

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