A level shifter includes a power supply rail conversion block, an RS latch and a digital detection block. The power supply rail conversion block comprises a first NLDMOS transistor, a second NLDMOS transistor, a first PLDMOS transistor, a second PLDMOS transistor, a first PMOS transistor, a second PMOS transistor, a first NMOS transistor, a second NMOS transistor, and a first inverter. A gate of the first NLDMOS transistor is connected to an input of the first inverter, a drain of the first NLDMOS transistor is connected to a drain of the first PLDMOS transistor; a source of the first NLDMOS transistor and a source of the second NLDMOS are connected to a referenced ground of an LV power supply rail. The digital detection block comprises a second inverter, a third inverter, a first delay chain, a second delay chain, a first NAND gate and a second NAND gate.

Level-shifting circuits including a plurality of p-type metal oxide semiconductor (PMOS) devices and n-type metal oxide semiconductor (NMOS) devices may be used to level-shift an input voltage signal between a low voltage domain having a low voltage level and a high voltage domain having a high voltage level, to obtain an output voltage signal having an output voltage level at an output node. A current-controlled tie circuit may be connected between the output node and the output voltage level, to conduct a current that causes the output node of the level-shifting circuit to be in a pre-defined logic state during a power-up sequence of the level-shifting circuit. Accordingly, spurious, non-deterministic output levels are avoided during the power-up sequence.

This application relates to methods and apparatus for voltage control, and in particular to maintain safe voltages for components of audio driving circuits that are operable in a high voltage mode. An audio driving circuit (100) may include a power supply module (106) and may be operable such that, in use, a voltage magnitude at a source terminal of at least a first transistor (306, 309, 603, 605) of the audio driving circuit can exceed its gate-source voltage tolerance. A voltage generator (111P) is configured to output a first intermediate voltage (V.sub.SAFEP) to an intermediate voltage path for use as a gate control voltage for at least the first transistor, to maintain its gate-source voltage below tolerance. An intermediate path voltage clamp (114P) is provided for selectively clamping the intermediate voltage path to a voltage level, so as to maintain the magnitude of the gate-source voltage of the first transistor below tolerance. The voltage clamp (114P) is enabled by a reset condition (RST) for the audio driving circuit.

A voltage level shifter device an input stage and an output stage. The input stage is configured to lower one of the first and second output terminals to the low level according to the level of the input voltage. A latch circuit includes a first branch having a first PMOS transistor and a second PMOS transistor coupled in series coupled between a shifted-high-level voltage supply terminal and the first output terminal and a second branch having a third PMOS transistor an a fourth PMOS transistor coupled in series between the shifted-high-level voltage supply terminal and the second output terminal. The first output terminal is a gate of the second PMOS transistor and to a gate of the third PMOS transistor. The second output terminal is coupled a gate of the fourth PMOS transistor and to a gate of the first PMOS transistor.

A circuit includes a level shifter circuit, an output circuit and a feedback circuit. The level shifter circuit is coupled to a first voltage supply, and is configured to receive at least an enable signal, a first input signal or a second input signal. The level shifter circuit is configured to generate at least a first signal responsive to at least the enable signal or the first input signal. The output circuit is coupled to at least the level shifter circuit and the first voltage supply, is configured to receive the first signal, and to generate at least an output signal or a set of feedback signals responsive to the first signal. The feedback circuit is coupled to the level shifter circuit, the output circuit and the first voltage supply, and is configured to receive the enable signal, an inverted enable signal and the set of feedback signals.

Disclosed are level shifters and methods of performing level shifting. In one embodiment, a level shifter is disclosed comprising an input, cross-coupled/latch circuitry, a first reference node, a second reference node, and output circuitry coupled between the cross-coupled/latch circuitry and an output, wherein the output circuitry sets the output signal to high based on rising edge of a second reference node and sets the output signal to low based on the rising edge of the first reference node. Further, the first reference node and the second reference node are symmetric nodes having signals that are inverse to each other.

A semiconductor device includes a circuit-to-be-adjusted in which an output characteristic thereof can be adjusted by a fuse that is controlled based on a fuse signal. The semiconductor device includes a control circuit using, as a power source, an internal power source that has a converted voltage obtained by converting a voltage of an external power source, the control circuit being configured to generate control signals A, B based on an inputted test signal, the control signals being able to adjust the circuit-to-be-adjusted in place of the fuse signal. The semiconductor device includes a selector circuit that selects the fuse signal before the internal power source reaches a stable state after the external power source is turned on, and selects the control signal CS after the internal power source has reached a stable state.

A method for high-speed voltage level translation includes biasing a high-voltage (HV) gate of an HV transistor to an intermediate voltage with a bias device. A low-voltage (LV) transistor is activated with a positive voltage transition applied to an LV gate of the LV transistor, wherein the HV transistor is connected in series between an output and an LV drain of the LV transistor. The intermediate voltage is bootstrapped to a bootstrapped voltage in response to the positive voltage transition on the LV gate coupled to the HV gate through a capacitor therebetween. The output is discharged. A time constant, defined by a resistance of the bias device and a capacitance of the capacitor, is greater than a minimum time constant, thereby maintaining the bootstrapped voltage on the HV gate at or above a drive voltage for a minimum period to discharge the output to a minimum voltage.

A semiconductor device includes a circuit-to-be-adjusted in which an output characteristic thereof can be adjusted by a fuse that is controlled based on a fuse signal. The semiconductor device includes a control circuit using, as a power source, an internal power source that has a converted voltage obtained by converting a voltage of an external power source, the control circuit being configured to generate control signals A, B based on an inputted test signal, the control signals being able to adjust the circuit-to-be-adjusted in place of the fuse signal. The semiconductor device includes a selector circuit that selects the fuse signal before the internal power source reaches a stable state after the external power source is turned on, and selects the control signal CS after the internal power source has reached a stable state.

Various implementations described herein refer to an integrated circuit having a first stage and a second stage. The first stage has first transistors arranged as a diode, a first latch and feedback assist to facilitate shifting an input voltage in a first voltage domain to an output voltage in a second voltage domain. The first stage uses the diode and the first latch to reduce contention between the first latch and input transistors. The diode, the first latch and the feedback assist enable activation of the input transistors with the input voltage. The second stage has second transistors arranged as a second latch followed by output buffers that provide a buffered output voltage as feedback to the feedback assist of the first stage.