Seiko Epson Corporation

Masuhide Ikeda

Akihiko Ito

Makoto Katase

Takashi Kurumisawa

Shingo Isozaki

In a static electricity protection circuit, an N+ embedded region is provided, extending over an upper surface of a P-type P semiconductor substrate. One N−-semiconductor region, another N−-semiconductor region, and an N− common impurity region are provided in an upward direction from the N+ embedded region. The one N−-semiconductor region and the other N−-semiconductor region are coupled together via the N− common impurity region. A P− impurity region is provided in the upward direction from the one N−-semiconductor region. Another P− impurity region is provided in the upward direction from the other N−-semiconductor region. A diode formed by the one P− impurity region and the one N−-semiconductor region and a diode formed by the other P− impurity region and the other N−-semiconductor region are coupled in opposite directions to each other via the N− common impurity region.

Static electricity protection circuit, semiconductor device, and electronic apparatus

An ESD protection circuit includes a power MOS transistor disposed between a first line and a second line, a clamp circuit disposed between the first line and a first node to which a gate of the power MOS transistor is coupled, a first resistor disposed between the first node and the second line, a MOS transistor disposed between the first node and the second line, a third line supplied with a third potential generated by a constant-voltage circuit of the protection target circuit, and a second resistor and a first capacitor coupled in series between a second node coupled to the third line and the second line, wherein when defining a junction between the second resistor and the first capacitor as a third node, a gate of the MOS transistor is coupled to the third node.

ESD protection circuit, semiconductor device, and electronic apparatus

An electrostatic protection circuit that is electrically connected to a first terminal to which a first voltage signal is input, a second terminal to which a second voltage signal is input, and a connection terminal that is connected to an external circuit, and mitigates the influence of a surge voltage on an internal circuit, the electrostatic protection circuit including: a first protection circuit that is electrically connected to the first terminal and the second terminal; and a second protection circuit that is electrically connected to the first terminal and the connection terminal, and the second protection circuit including: a first diode element whose anode is electrically connected to the connection terminal, and whose cathode is electrically connected to the first terminal, a thyristor element whose cathode is electrically connected to the connection terminal, a voltage limiting element that is electrically connected to an anode of the thyristor element, and a trigger element that is electrically connected to a gate of the thyristor element, and causes the thyristor element to operate.

Electrostatic protection circuit

An electrostatic protection circuit that is electrically connected to a first terminal to which a first voltage signal is input, a second terminal to which a second voltage signal whose potential is lower than that of the first voltage signal is input, and a connection terminal that is connected to an external circuit, and mitigates the influence of a surge voltage on an internal circuit, the electrostatic protection circuit including: a discharge node that is electrically connected to the first terminal via a first diode element; a first protection circuit that is electrically connected to the first terminal and the second terminal; a second protection circuit that is electrically connected to the discharge node and the connection terminal; and a third protection circuit that is electrically connected to the discharge node and the second terminal, and an anode of the first diode element is electrically connected to the first terminal, and a cathode of the first diode element is electrically connected to the discharge node.

This electrostatic protection circuit enables a trigger voltage to be set arbitrarily and enables a high hold voltage to be set, without providing an RC timer having a large circuit area. This electrostatic protection circuit is connected to a first terminal via a first node and is connected to a second terminal via a second node. The electrostatic protection circuit is provided with a plurality of circuit blocks that are connected in series between the first node and the second node, and at least one circuit block out of the plurality of circuit blocks includes a zener diode for setting a trigger voltage. The electrostatic protection circuit enters a conduction state when the potential of the first node becomes higher than the potential of the second node and the voltage between both ends of the circuit block including the zener diode reaches the breakdown voltage of the zener diode.

Electrostatic protection circuit, semiconductor integrated circuit device, and electronic device

This electrostatic protection circuit enables a high hold voltage to be set, and acts to accurately prevent breakdown of a protected circuit immediately after power on, and to prevent breakdown or deterioration of a protection device during prolonged normal operation, without connecting a resistance element in parallel to a plurality of circuit blocks connected in series. This electrostatic protection circuit is provided with a plurality of circuit blocks connected in series between a first node and a second node, at least one circuit block out of the plurality of circuit blocks including a thyristor having an anode connected to one end of the at least one circuit block and a cathode connected to the other end of the at least one circuit block. When the potential of the first node is higher than the potential of the second node during normal operation, the voltage between both ends of the other circuit blocks out of the plurality of circuit blocks is smaller than the voltage between the anode and the cathode of the thyristor.

This static electricity protection circuit starts a discharge operation only if an applied voltage is greater than or equal to a set voltage, and protects a discharge circuit also when noise or the like is applied during a normal operation. This static electricity protection circuit includes: a resistor Rand clamp circuit that are connected in series between nodes Nand N; a first transistor that turns on in accordance with an increase in a potential difference generated in the resistor R; a resistor Rand capacitor Cthat are connected via a node Nbetween the nodes Nand N; a second transistor that is connected in series with the first transistor between the nodes Nand N; a resistor Rconnected between the nodes Nand N; a third transistor connected between the nodes Nand N; and a discharge circuit connected between the nodes Nand N

Static electricity protection circuit, semiconductor integrated circuit device, and electronic apparatus

This electrostatic protection circuit makes it possible for a discharge operation to be started only in the case where a rise in an applied voltage is steep, and for static electricity to be sufficiently released. This electrostatic protection circuit includes a discharge circuit that is connected between a first node and a second node and discharges charge produced by static electricity, a latch circuit that is connected between the first node and the second node and outputs a signal that controls operation of the discharge circuit to the discharge circuit, a switch circuit that is connected to the latch circuit and changes the signal that controls operation of the discharge circuit, and a control circuit that is connected between the first node and the second node and outputs a signal that controls operation of the switch circuit to the switch circuit.

Electrostatic protection circuit and semiconductor integrated circuit apparatus

Provided is an electrostatic protection circuit that has little leakage current under normal operation and allows a trigger voltage to be set comparatively freely, without requiring a special process step. This electrostatic protection circuit is provided with a series circuit including a transistor, a predetermined number of diodes and an impedance element that are connected in series between the first node and the second node, and a discharge circuit configured to send current from the first node to the second node following an increase in a potential difference that occurs between both ends of the impedance element, when the first node reaches a higher potential than the second node and current flows through the series circuit. The predetermined number of diodes are connected between the source and the back gate of the transistor.

The present electrostatic protection circuit includes: a series circuit that is connected between a first node and a second node and includes a first impedance element and a clamp element connected to each other by a third node; a first transistor that is connected between the first node and a fourth node and turns on in accordance with an increase in voltage generated in the first impedance element; a second impedance element connected between the fourth node and the second node; a second transistor that turns on in accordance with an increase in voltage generated in the second impedance element, and increases current flowing in the first impedance element; and a discharge circuit that allows current to flow from the first node to the second node when the second transistor is in an on state.

The following are included: a series circuit that is connected between a first node and a second node and includes an impedance element and a capacitor connected to each other by a third node; a first transistor that is connected between the first node and a fourth node and turns on in accordance with an increase in voltage generated in the impedance element; a voltage divider circuit that divides voltage between the fourth node and the second node; a second transistor that turns on in accordance with an increase in the divided voltage and increases current flowing in the impedance element; a detection circuit that activates an output signal upon detection of an on state of the second transistor; and a discharge circuit that allows current to flow from the first node to the second node when the output signal of the detection circuit is activated.

The invention provides an electrostatic protection circuit that is effective in absorbing static electricity that is continuously input. The electrostatic protection circuit includes a circuit constituting a latch and a static electricity absorption circuit. When static electricity is input, the static electricity absorption circuit maintains its on state for a while at an output held by the latch circuit, and absorbs static electricity that is continuously input. When the static electricity has been absorbed, the output of the latch is inverted so as to turn off the static electricity absorption circuit, and the operation of absorbing static electricity ends. At this point in time, normal operation serving as an input terminal is performed.

Electrostatic discharge protection circuit and semiconductor circuit device

A depletion type PMOS transistor Q and an enhancement type PMOS transistor Q are serially connected to each other between power supply lines and . A gate electrode of the PMOS transistor Q is formed from polysilicon including a P-type impurity and connected to a source electrode thereof. A gate electrode of the PMOS transistor Q is formed from polysilicon including an N-type impurity and connected to a drain electrode thereof. A voltage corresponding to a difference between a threshold voltage of the PMOS transistor Q and a threshold voltage of the PMOS transistor Q is generated at a mutually connected section of the both MOS transistors as a reference voltage.

Reference voltage circuit

A voltage conversion circuit incorporate many of what were previously discrete components into a single IC, whereby the number of externally disposed discrete components is reduced as much as possible to reduce the overall size while maintaining high power conversion efficiency. This is achieved by using multiple wells within wells, and coupling the wells to specific voltage potentials to protect the circuit from failure.

Voltage conversion circuit

The invention provides an operation amplification circuit and the like that can reduce current consumption, is not dependent on the power supply voltage, and can suppress mass-production variations. The present invention is equipped with a bias circuit, a differential amplification circuit and an output amplification circuit. The bias circuit includes a reference voltage circuit and a current mirror circuit. The reference voltage circuit includes a depletion type PMOS transistor and an enhancement type PMOS transistor serially connected to each other. The MOS transistor has a gate electrode that is formed from polysilicon including a P-type impurity, and the MOS transistor has a gate electrode that is formed from polysilicon including an N-type impurity. Furthermore, a voltage corresponding to a difference between threshold voltages of the MOS transistors is generated at a commonly connected section of the MOS transistors as a reference voltage.

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Matsumoto, Japan

Masuhide Ikeda