The present application provides a level shifter comprising a first P-type transistor; a second P-type transistor; a third P-type transistor, coupled to the second P-type transistor; a fourth P-type transistor, coupled to the first P-type transistor; a first N-type transistor, coupled to the third P-type transistor; a second N-type transistor, coupled to the fourth P-type transistor; a third N-type transistor, coupled to the first N-type transistor; a fourth N-type transistor, coupled to the second N-type transistor; and an inverter, coupled between the third N-type transistor and the fourth N-type transistor, wherein an input terminal of the inverter receives an input signal of the level shifter.

A Schmitt trigger circuit includes a first circuit; a second circuit; a first switch; a third circuit; and a second switch. The first circuit output the output signal of a second or first logical level. The second circuit is coupled to a first potential node at a first end, and sends a current between the first end and a second end based on the output signal. The first switch electrically couples or uncouples the second end and a first node based on a selection signal. The third circuit is coupled to a second potential node at a third end, and sends a current exclusively with the second circuit between the third end and a fourth end based on the output signal. The second switch electrically couples or uncouples the fourth end and the first node based on the selection signal.

An apparatus and method for operating a level shifter circuit that receives an input signal of interderminate voltage level is disclosed. The level shifter circuit may receive the input signal from a circuit block coupled to a first power supply signal, and generate an output signal using a second power supply signal, different than the first power supply signal. The level shifter circuit may clamp a storage node included in the level shifter circuit, and isolated at least one circuit path included in the level shifter circuit in response to a determination that an isolation signal has been enabled.

Techniques are disclosed for a level shifter configured to adjust current flow in response to measured current fluctuations due to common mode noise in the level shifter. For example, the level shifter includes a low-side control circuit configured to adjust a first current flowing into a first low-side terminal of an active high voltage level shifter device in response to a difference between the first low-side current and a second low-side current flowing into a second low-side terminal of an inactive high voltage level shifter device. The level shifter further includes a high-side receiver circuit configured to detect a difference between a first high-side current flowing into a first high-side terminal of the active high voltage level shifter device and a second high-side current flowing into a second high-side terminal of the inactive high voltage level shifter device.

A buffer circuit includes a transistor cascode circuit, a latch circuit, a first transistor, a second transistor, and a voltage generator. The transistor cascode circuit is biasing at a first voltage. The latch circuit is biasing at a second voltage, whose voltage level is negative. The first transistor and the second transistor are coupling between the transistor cascode circuit and the latch circuit, and a gate of the first transistor is coupled to a gate of the second transistor. The voltage generator provides a biasing voltage to the gate of the first transistor and adjusts a voltage level of the biasing voltage dynamically according to a voltage level of the second voltage. The biasing voltage is at a first level when the buffer circuit is initially turned on, and the biasing voltage is at a second level when the buffer circuit enters the steady state.

Methods and systems are provided for generating an oscillating signal for use as a clock in digital logic timing. The oscillating signal is generated via a differential RC relaxation oscillator including an oscillator core and biasing circuitry. The oscillator core may be configured such that the oscillating signal it generates is substantially sinusoidal or pseudo-sinusoidal and contains less harmonic content relative to a square wave signal. The biasing circuitry may be configured to have a reduced dependence on temperature so that the biasing values it provides vary less with temperature.

A sequential state element (SSE) is disclosed. In one embodiment, an SSE includes a differential sense flip flop (DSFF) and a completion detection circuit (CDC) operably associated with the DSFF. The DSFF is configured to generate a differential logical output. During a normal operational mode, the DSFF is synchronized by a clock signal to provide a differential logical output in a differential output state in accordance with a data input or in a precharge state based on the clock signal. The differential logical output is provided in a differential output state in accordance with a test input during a scan mode. The CDC is configured to generate a test enable input during the scan mode that indicates the scan mode once the differential logical output is in the differential output state. Accordingly, another SSE can be asynchronously triggered to operate in the scan mode without a separate scan clock.

A novel PLL is provided. An oscillator circuit includes first to n-th inverters, and first and second circuits. A first terminal of each of the first and second circuits is electrically connected to an output terminal of the i-th inverter. A second terminal of each of the first and second circuits is electrically connected to an input terminal of the (i+1)-th inverter. The first circuit has functions of storing first data, switching between electrically disconnecting the first terminal and the second terminal from each other and setting a resistance between the first terminal and the second terminal to a value based on the first data. The second circuit has functions of storing second data, switching between electrically disconnecting the first terminal and the second terminal from each other and setting a resistance between the first terminal and the second terminal to a value based on the second data.

Techniques are disclosed for a level shifter configured to adjust current flow in response to measured current fluctuations due to common mode noise in the level shifter. For example, the level shifter includes a low-side control circuit configured to adjust a first current flowing into a first low-side terminal of an active high voltage level shifter device in response to a difference between the first low-side current and a second low-side current flowing into a second low-side terminal of an inactive high voltage level shifter device. The level shifter further includes a high-side receiver circuit configured to detect a difference between a first high-side current flowing into a first high-side terminal of the active high voltage level shifter device and a second high-side current flowing into a second high-side terminal of the inactive high voltage level shifter device.

A level conversion circuit includes: first P-ch and N-ch transistors and second P-ch and N-ch transistors respectively connected in series between first and second power sources; third and fourth P-ch transistors respectively connected between the gates of the second and first P-ch transistors and the drain of the first and second P-ch transistors; and fifth and sixth P-ch transistors respectively connected between the gates of the second and first P-ch transistors and a third power source, wherein differential input signals are applied to the gates of the first and second N-ch transistors, a bias voltage is applied to the gates of the third and fourth P-ch transistors, the gate of the fifth and sixth P-ch transistors are respectively connected to connection nodes of the first P-ch and N-ch transistors the second P-ch and N-ch transistors.