High-voltage electrostatic protection circuit and its low-voltage source trigger electrostatic current discharge circuit

Abstract

The invention relates to a high-voltage electrostatic protection circuit and a low-voltage source-triggered electrostatic current discharge circuit thereof. The low-voltage source-triggered electrostatic current discharge circuit is formed by connecting a plurality of low-voltage substrate isolation transistors in series, and the total breakdown voltage after series connection is applicable to a high-voltage system power supply; the source of each low-voltage substrate isolation transistor is connected to the switching circuit of the high-voltage electrostatic protection circuit and is not connected to the substrate to improve the trigger efficiency; the drain of each low-voltage substrate isolation transistor also keeps at a certain interval with the sidewalls of the gate insulating layerof the gate to increase the electrostatic discharge withstand voltage; and when the static electricity occurs, the switch circuit triggers the conduction of the respective low-voltage substrate isolation transistors to smoothly eliminate the electrostatic current.

Description

technical field [0001] The invention relates to a high-voltage electrostatic protection circuit, in particular to a high-voltage electrostatic protection circuit with a low-voltage source triggering an electrostatic current discharge circuit. Background technique [0002] In an integrated circuit using a high-voltage voltage source, a high-voltage electrostatic protection circuit is usually designed at the output and input terminals of the integrated circuit to prevent static electricity from discharging to the interior of the integrated circuit through the output and input terminals, causing circuit damage. [0003] Please refer to Figure 7 As shown, it is a common high-voltage electrostatic protection circuit, which includes an electrostatic detection circuit 50 and a high-voltage gate-triggered transistor 60. The gate-triggered transistor 60 is connected in parallel with the electrostatic detection circuit 50 and connected to the high-voltage voltage Between the high vol...

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Problems solved by technology

However, the high-voltage gate-triggered transistor 60 itself is a high-voltage MOS element, so its trigger voltage is relatively high, and it is difficult to protect the internal high-voltage circuit components. In addition, its internal resistance is relatively high, so that after conduction, the electrostatic current discharge speed is slow. , and it is necessary to further improve the

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