Static protection circuit

Abstract

The present invention relates to an electrostatic protection circuit for protecting an internal circuit. The internal circuit is connected with a converter, and can be driven by first and second voltage source. The converter can convert first input signal which is received by input soldering lug and has first magnitude into second input signal with second magnitude and input it into internal circuit. Between the input soldering lug and first voltage source the mutually-reversed first and second diodes are connected. Said electrostatic protection circuit includes a transistor, an inverter, a resistor, a capacitor and a voltage clamper. The source of the transistor is connected between two diodes, its drain is connected with second voltage source, the outupt end of the inverter is connected with grid of transistor, the resistor is connected between the source of transis

Description

technical field

[0001] The present invention relates to an ESD protection circuit, in particular to an ESD protection circuit suitable for an integrated circuit with a 5V to 3V converter, which can avoid high voltage accumulation on a floating ESD bus. Background technique

[0002] figure 1 An ESD protection circuit for a converter with 5 volts to 3 volts in conventional technology is shown. It includes a main protected internal circuit 11, a 5-volt to 3-volt converter 12, an output circuit 13, an input pad (pad) 14, an output pad 15, four electrostatic protection circuits 16a, 16b, 17a, 17b, a floating electrostatic discharge bus 18, a diode 19 and a resistor R. In addition, all active components are driven by two voltage sources providing VDD and VSS voltages.

[0003] Wherein, since the VDD voltage used by the internal circuit 11 is 3 volts, and the amplitude of the input signal received by the input pad 14 is 5 volts, the 5-volt to 3-volt con...

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