Electrostatic discharge protection circuit
AssigneesInteruniversitair Microelektronica Centrum (IMEC), AMI Semiconductor, Inc.
InventorsKoen Reynders, Mahmud Zubeidat, Vincent De Heyn
Life of this patent
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Abstract
An electrostatic discharge (ESD) protection circuit for the protection of an electronic circuit from an ESD event. The electronic circuit, in operation, is provided with a supply voltage and a reference voltage (typically electrical ground) via voltage terminals and/or power supply buses. The protection circuit includes two bipolar transistors in series, where the transistors are coupled between the supply voltage terminal/bus and the reference voltage terminal/bus. The bases of the transistors are coupled via a connection including two resistors in series, where the connection point between the two resistors is coupled with the connection point between the two transistors.
Claims18
A protection circuit for protecting an electronic circuit from an electrostatic discharge (ESD) event, the electronic circuit, in operation, being supplied a supply voltage via a supply voltage terminal, with respect to a reference voltage, the reference voltage being supplied via a reference voltage terminal, the protection circuit comprising:
- a set of at least two bipolar transistors coupled in series, each two neighboring transistors being coupled with respective first connections between a collector of one transistor and an emitter of the other transistor, the set of at least two transistors being further coupled with the supply voltage terminal and the reference voltage terminal, a first of the transistors being directly coupled with the supply voltage terminal and a second of the transistors being directly coupled with the reference voltage terminal,
- wherein the bases of every two neighboring transistors are interconnected by respective second connections,
- wherein the second connections between the bases each consist of two resistances coupled in series through respective third connections, and
- wherein respective fourth connections couple the respective first and third connections.
An electronic device that, in operation, is supplied a supply voltage via a supply voltage terminal, with respect to a reference voltage, and the reference voltage is supplied via a reference voltage terminal, the electronic device including a protection circuit comprising:
- a set of at least two bipolar transistors coupled in series, each two neighboring transistors being coupled with respective first connections between a collector of one transistor and an emitter of the other transistor, the set of at least two transistors being further coupled with the supply voltage terminal and the reference voltage terminal, a first of the transistors being directly coupled with the supply voltage terminal and a second of the transistors being directly coupled with the reference voltage terminal,
- wherein the bases of every two neighboring transistors are interconnected by respective second connections,
- wherein the second connections between the bases each consist of two resistances coupled in series through respective third connections, and
- wherein respective fourth connections couple the respective first and third connections.
An electrostatic discharge (ESD) protection circuit comprising:
- a first NPN transistor;
- a second NPN transistor, wherein a collector of the second NPN transistor is coupled with an emitter of the first NPN transistor via a first connector;
- a first resistor having a first terminal and a second terminal, wherein the first terminal of the first resistor is coupled with a base of the first NPN transistor via a second connector;
- a second resistor having a first terminal and a second terminal, wherein the first terminal of the second resistor is connected to the second terminal of the first resistor via a third connector and the second terminal of the second resistor is coupled with a base of the second NPN transistor via a fourth connector;
- and
- a fifth connector coupling the first connector with the third connector.
A method of protecting an electronic circuit from an electrostatic discharge (ESD) event, the method comprising:
- providing a protection circuit coupled between a supply voltage terminal and a reference voltage terminal of the electronic circuit;
- receiving an ESD pulse at a base-collector junction of a first NPN transistor of the protection circuit, the ESD pulse causing breakdown of the base-collector junction, resulting in snap-back of the first NPN transistor;
- communicating current from the base of the first NPN transistor to a base of a second NPN transistor using a voltage divider consisting of a first resistance and a second resistance;
- diverting at least a portion of the current between the first resistance and the second resistance to an emitter of the first NPN transistor and a collector of the second NPN transistor;
- and
- controlling the current communicated from the base of the first NPN transistor to the base of the second NPN transistor with resistance values of the first resistance and the second resistance.
Dependencies are inferred from the claim text.