A circuit includes a first pair of transistors coupled in series between a supply voltage node and an output node and a second pair of transistors coupled in series between the output node and a ground node. The circuit further includes a first diode-connected transistor coupled between a first node between the first pair of transistors and the output node, and a second diode-connected transistor coupled between a second node between the second pair of transistors and the output node.

A data retention circuit is provided in the invention. The data retention circuit includes a master latch circuit, a slave latch circuit, and a control circuit. The control circuit is coupled to the master latch circuit and the slave latch circuit and receives a clock signal from a clock circuit and a power management signal from a power management unit (PMU). In a normal operation mode, the control circuit transmits the clock signal to the master latch circuit and the slave latch circuit. In sleep mode, power to the master latch circuit is switched off and the control circuit transmits the power management signal to the slave latch circuit.

This invention is a retention circuit retaining the state of a circuit node driven by a primary drive circuit. This circuit includes cross coupled first and second inverters and a transmission gate. The transmission gate receives a retention mode signal and isolates the retention circuit and the circuit node when a retention mode is active and connects the retention circuit and the circuit node when the retention mode is inactive. In the preferred embodiment the primary drive circuit is constructed of transistors having a standard voltage threshold and the retention circuit is constructed of transistors having a high voltage threshold greater than said standard voltage threshold. A tristate inverter isolates the retention circuit from the circuit node when not in retention mode and supplies an inverse of a signal from output of said first inverter when in retention mode.

A state retention circuit for retaining the state of a data storage element during a power reduction mode including a storage latch and a retention latch both powered by retention supply voltage that remains energized during a power reduction mode. The storage latch and the retention latch are both coupled to a retention node that is toggled from between first and second states before entering the power reduction mode so that the storage latch latches the state of the data storage element. The retention latch includes a retention transistor and a retention inverter powered by the retention supply voltage. The retention transistor is overpowered when the retention node is pulled to the second state in which the retention inverter quickly turns off the retention transistor. When the retention node is toggled back to the first state, the retention inverter keeps the retention transistor turned on during the power reduction mode.

In at least one general aspect, an apparatus can include a first voltage domain circuit configured to operate based on a first upper voltage and a first lower voltage, and a second voltage domain circuit configured to operate based on a second upper voltage and a second lower voltage. The apparatus can include a capacitive coupling circuit electrically connected between the first voltage domain circuit and the second voltage domain circuit, and a driver circuit including a switch device and electrically coupled to the second voltage domain circuit. The apparatus can also include an intermediate voltage domain circuit configured to trigger switching of the switch device included in the driver circuit where the intermediate voltage domain is configured to operate based on an intermediate voltage and the second upper voltage or the second lower voltage.

A power-on reset (POR) circuit includes: a signal generator circuit for generating a first and a second signal according to an input voltage, and a comparator circuit. The comparator circuit, having a non-zero input offset, includes a first MOS transistor with a first conductive type and having a first conductive type gate and a first threshold voltage, and a second MOS transistor with a first conductive type and having a second conductive type gate and a second threshold voltage. The input offset relates to a difference between the first and the second threshold voltage. The first and the second signal control the first and the second MOS transistors respectively to generate a POR signal. When the input voltage exceeds a POR threshold which relates to a predetermined multiple or ratio of the input offset, the POR signal transits its state.

A semiconductor circuit in the disclosure includes a first circuit that is able to generate, on the basis of a voltage in a first node, an inverted voltage of the voltage and to apply the inverted voltage to a second node; a second circuit that is able to generate, on the basis of a voltage in the second node, an inverted voltage of the voltage and to apply the inverted voltage to the first node; a first transistor that couples the first node to a third node; a second transistor that supplies a first direct-current voltage to the third node; a third transistor including a drain or a source to be coupled to the third node and including a gate coupled to the first node or the second node; and a first storage element that is coupled to the third node, and is able to take a first resistance state or a second resistance state. The first circuit and the second circuit are configured to cause the voltage in the first node to easily become a predetermined initial voltage after application of power.

Two retention flip-flop topologies that utilize a data retention control circuit and a slave/retention latch (sub-circuit) to reliably retain a data bit during standby/sleep operating modes without the need for a local clock signal. The slave/retention latch is controlled using a local clock signal to store sequentially received data bit values during normal operating modes. During standby/sleep modes, the local clock signal is de-activated (i.e., by turning off the supply voltage provided to the local clock generator circuit), and the data retention control circuit operates in accordance with an externally supplied retention enable control signal to both isolate and control the slave/retention latch such that a last-received data bit value is reliably retained in the slave/retention latch. When normal operation is resumed, the local clock signal is re-activated, and the data retention control circuit controls the slave/retention latch to pass the last-received data bit value to an output driver.

A semiconductor device that has a long data retention time during stop of supply of power supply voltage by reducing leakage current due to miniaturization of a semiconductor element. In a structure where charge corresponding to data is held with the use of low off-state current of a transistor containing an oxide semiconductor in its channel formation region, a transistor for reading data and a transistor for storing charge are separately provided, thereby decreasing leakage current flowing through a gate insulating film.

An integrated circuit includes a pulse generator having at least one delay circuit with an input that receives a clock signal and an output that provides a delayed clock pulse. The delayed clock pulse has a width proportional to an amount of time required to maintain a magnitude of the clock signal. A pulse latch circuit includes a clock input coupled to receive the delayed clock pulse, a data input coupled to receive a data value, and a data output, wherein the pulse latch circuit outputs and holds the data value at the data output each time the delayed clock pulse is provided at the clock input, and the pulse latch circuit operates on a continuous voltage source that supplies power during power on and power off modes.