Semiconductor circuit having input protective circuit
AssigneeNEC Corporation
InventorToshio Watanabe
Life of this patent
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Abstract
Disclosed herein is an input protection circuit for a semiconductor device, which includes a first node, a second node, a power supply line, an input terminal connected to directly said first node, a first resistor connected between said first node and second node for decreasing surge voltage to said internal circuit from said input terminal, a first discharge circuit connected between said second node and said power supply line, and a second discharge circuit connected between said first node and said power supply line. The second node is in turn connected to an internal circuit having a MOS transistor to be protected.
Claims23
A semiconductor device having an input protective circuit for an internal circuit, said input protective circuit comprising:
- a first node;
- a second node connected to said internal circuit;
- a power supply line;
- an input terminal connected to said first node without an intervention of a substantial impedance;
- a first resistor connected between said first node and second node;
- a first discharge circuit connected between said second node and said power supply line;
- and
- a second discharge circuit connected between said first node and said power supply line.
A semiconductor device having an input protective circuit for a MOS transistor, said circuit comprising:
- a first node;
- a second node connected to said MOS transistor;
- a first power supply line;
- an input terminal connected directly to said first node;
- a first resistor connected between said first node and second node;
- a first discharge circuit connected between said second node and said first power supply line and having a first threshold level, said first discharge circuit comprising at least one diode connected between said second node and said first power supply line;
- and
- a second discharge circuit connected between said first node and said first power supply line and having a second threshold level larger than said first threshold level, said second discharge circuit having at least one diode connected between said second node and said first power supply line.
A surge protection circuit, comprising:
- an input terminal;
- a line having a first end connected to said input terminal, a first node directly connected to said first end, a second end opposite said first end and a second node directly connected to said second end;
- a first surge protector connected to said first node and to a voltage source;
- and
- a second surge protector connected to said second node and said voltage source,
- wherein said line includes a resistor between said first node and said second node.
A semiconductor device having an input protective circuit for an internal circuit, said input protective circuit comprising:
- a first node;
- a second node connected to said internal circuit;
- a first power supply line;
- a second power supply line;
- an input terminal directly connected to said first node;
- a first resistor connected between said first node and said second node;
- a second resistor connected between said first node and said second power supply line;
- a first discharge circuit, connected between said second node and said first power supply line, having a first positive breakdown voltage and a first negative breakdown voltage, said first discharge circuit disconnecting a current path between said second node and said first power supply line when said second node has a voltage between said first positive breakdown voltage and said first negative breakdown voltage;
- and
- a second discharge circuit, connected between said first node and said first power supply line, having a second positive breakdown voltage and a second negative breakdown voltage, said second discharge circuit disconnecting a current path between said first node and first power supply line when said first node has a voltage between said second positive breakdown voltage and said second negative breakdown voltage.
A semiconductor device having an input protective circuit for a MOS transistor, said circuit comprising:
- a first node;
- a second node connected to said MOS transistor;
- a first power supply line;
- a second power supply line;
- an input terminal directly connected to said first node;
- a first resistor connected between said first node and said second node;
- a second resistor connected between said first node and said second power supply line;
- and
- a first discharge circuit connected between said second node and said first power supply line and having a first positive breakdown voltage, said first discharge circuit disconnecting a current path between said second node and said first power supply line when said second node has a voltage between said first positive breakdown voltage and a first negative breakdown voltage.
Dependencies are inferred from the claim text.