摘要:
A level shift circuit including a level conversion unit that converts an input signal having a signal level of a first voltage into a signal having a signal level of a second voltage that is higher than the first voltage. The level conversion unit includes first and second MOS transistors of a first conductivity type and third and fourth MOS transistors of a second conductivity type, which differs from the first conductivity type and of which switching is controlled in accordance with the input signal. The third and fourth MOS transistors include drains supplied with the second voltage via the first and second MOS transistors, respectively. A control unit, when detecting a decrease in the first voltage, controls a body bias of the third and fourth MOS transistors to decrease a threshold voltage of the third and fourth MOS transistors.
摘要:
A leak current detection circuit that improves the accuracy for detecting a leak current in a MOS transistor without enlarging the circuit scale. The leak current detection circuit includes at least one P-channel MOS transistor which is coupled to a high potential power supply and which is normally inactivated and generates a first leak current, at least one N-channel MOS transistor which is coupled between a low potential power and at least the one P-channel MOS transistor and which is normally inactivated and generates a second leak current, and a detector which detects a potential generated at a node between the at least one P-channel MOS transistor and the at least one N-channel MOS transistor in accordance with the first and second leak currents.
摘要:
An excluding unit is controlled by a control signal received from a control unit, and based on the control signal a determination is made for each of circuit blocks as to whether either a voltage signal at a position of its corresponding circuit block or a signal indicating a voltage is outputted to a selection unit. From a circuit block which is not in operation, the voltage, but not a voltage signal at a position of the circuit block, is outputted to the selection unit. By this, the circuit block which is not in operation cannot be judged to have voltage drop, and accordingly, a high supply voltage cannot be supplied. Consequently, a malfunction caused by supply voltages to other circuit blocks being too high does not occur.
摘要:
A level shift circuit determining a logic value while preventing load capacitance from increasing. A voltage detector detects the states of first and second voltages and generates first and second detection signals. A first logic unit generates a first control signal having a level that is in accordance with an input signal or a level of a third voltage in response to the first detection signal. A second logic unit generates a second control signal having a level that is in accordance with the first control signal or a level of the second voltage in response to the second detection signal. A level converter generates an output signal based on the first and second control signals and clamps the output signal at a fixed level when an abnormality occurs in the first voltage.
摘要:
The present invention aims to provide a multi-power supply circuit capable of generating multi-power efficiently and reducing power consumption, and a multi-power supply method therefor. A supply voltage is output from a DCDC converter. Output transistors of linear regulators are series-connected to a power supply path between a resistive element and the DCDC converter. That is, a bias current path is shared between the linear regulators and the corresponding path is taken as one. With the supply voltage as the reference, supply voltages corresponding to intermediate negative voltages between the supply voltage and a reference voltage are generated by the linear regulators. A bias current consumed by the multi-power supply circuit is held constant as a bias current i regardless of the number of the linear regulators.
摘要:
There is provided an oscillator circuit capable of obtaining stable frequency by avoiding output having unstable frequency that is likely to occur to an operation/stop-control-feasible type oscillator circuit when oscillation begins. In such an oscillator circuit, an oscillation permitting signal (EN) sets an oscillator section in oscillation-operable state, whereby a controller section starts operation. The controller section that has stared its operation change an oscillation-frequency control signal (VR) into a signal value corresponding to predetermined oscillation frequency so as to set oscillation frequency at an oscillator section. Further on, the oscillator section outputs an oscillation signal in response to a detection signal (MON) that is outputted after a detector section compares a signal inputted therein with a predetermined signal value and detects that the inputted signal reaches a predetermined signal value. Thereby, transient state of an oscillation-frequency control signal (VR) can be detected. That is, there can be avoided an output of an unstable oscillation signal due to a transient oscillation-frequency control signal (VR).
摘要:
There is provided an oscillator circuit capable of obtaining stable frequency by avoiding output having unstable frequency that is likely to occur to an operation/stop-control-feasible type oscillator circuit when oscillation begins. In such an oscillator circuit, an oscillation permitting signal (EN) sets an oscillator section in oscillation-operable state, whereby a controller section starts operation. The controller section that has stared its operation change an oscillation-frequency control signal (VR) into a signal value corresponding to predetermined oscillation frequency so as to set oscillation frequency at an oscillator section. Further on, the oscillator section outputs an oscillation signal in response to a detection signal (MON) that is outputted after a detector section compares a signal inputted therein with a predetermined signal value and detects that the inputted signal reaches a predetermined signal value. Thereby, transient state of an oscillation-frequency control signal (VR) can be detected. That is, there can be avoided an output of an unstable oscillation signal due to a transient oscillation-frequency control signal (VR).
摘要:
A flash-erasable semiconductor memory device has a memory cell array including a plurality of memory cell transistors each having an insulated floating gate for storing information and a control electrode provided on the floating gate, wherein the flash-erasable semiconductor memory device includes a write control circuit supplied with a write control signal, when writing information. The write control circuit produces a control signal such that a leading edge of the drain control signal appears after a leading edge of the gate control signal. Further, the gate control circuit shuts off the gate control signal such that a trailing edge of the gate control signal appears after a trailing edge of the drain control signal.
摘要:
A flash-erasable semiconductor memory device comprises a memory cell array including a plurality of memory cell transistors each having an insulated floating gate for storing information and a control electrode provided on said floating gate, wherein the flash-erasable semiconductor memory device includes a write control circuit supplied with a write control signal, when writing information. The write control circuit produces a control signal such that a leading edge of the drain control signal appears after a leading edge of the gate control signal. Further, the gate control circuit shuts off the gate control signal such that a trailing edge of the gate control signal appears after a trailing edge of the drain control signal.
摘要:
A nonvolatile semiconductor memory employs sense amplifiers, circuits for providing stabilized source voltages, and circuits for realizing high-speed and reliable read and write operations. The semiconductor memory has a matrix of nonvolatile erasable memory cell transistors. The semiconductor memory employs an arrangement for effectively using a plurality of source voltages and applying a verify voltage to sense amplifiers and word lines, a write verify arrangement for detecting an output of the sense amplifiers, an arrangement for comparing an output of the sense amplifiers with a reference value to determine whether or not a written state of the memory cell transistors is acceptable, an arrangement for adjusting an output of the sense amplifiers with use of inverters and transistors in response to a current flowing to the memory cell transistors, to improve a drive speed of the sense amplifiers, an internal source voltage generating arrangement using an n-channel depletion transistor connected to an external source voltage (Vcc), the gate of the transistor being connected to a low source voltage (Vss) to provide an internal source voltage (Vci), a combination of an arrangement for dropping the external source voltage (Vcc) for read to a predetermined value to drive a read circuit in the memory and an arrangement for dropping an external voltage (Vpp) for write, to generate a word line potential for a verify-after-write operation, an arrangement for setting a reference voltage (Vref) as a lower threshold (Vth) allowed for cell transistors (11.sub.00 to 11.sub.22), and comparing the voltage of a data bus (13) with the reference voltage (Vref), to simultaneously carry out an erase-verify operation on all memory cell transistors, and a pre-read arrangement for accessing the next address during a read time of the sense amplifiers, to improve a read speed.