摘要:
Flash memory array systems and methods are disclosed for producing a regulated boosted word line voltage for read operations. The system comprises a multi-stage voltage boost circuit operable to receive a supply voltage and one or more output signals from a supply voltage detection circuit to generate the boosted word line voltage having a value greater than the supply voltage. The voltage boost circuit comprises a precharge circuit and a plurality of boost cells connected to a common node of the boosted word line, and a timing control circuit. The stages of the plurality of boost cells are coupled in series for charge sharing between the stages, and couple a predetermined number of boost cells to the boosted word line common node to provide an intermediate voltage to the boosted word line during the pre-boost timing, thereby anticipating a final boosted word line voltage provided during the boost timing. The voltage boost circuit is operable to receive the one or more output signals from the supply voltage detection circuit and alter a boost gain of the multi-stage voltage boost circuit based on the one or more output signals, thereby causing the boosted word line voltage to be substantially independent of the supply voltage value.
摘要:
A bandgap reference circuit includes a current generation circuit connected to a voltage generation circuit connected to a smart clamping circuit, and a discharge circuit connected to the current generation circuit and the voltage generation circuit. The discharge circuit initially discharges a potential in the current and voltage generation circuits to improve repeatability. A start circuit within the current generation circuit then initializes the reference output at about the supply voltage to improve the speed and settling time of the output signal. The current generation circuit sources a current to the voltage generation circuit that translates the current having a positive function of temperature +TC into a reference voltage. The smart clamping circuit further generates a clamping voltage having a negative function of temperature −TC and a load resistance. The clamping voltage and the load resistance are applied across the reference voltage quickly reducing the reference voltage particularly at high temperatures and during start-up to a final level, thereby producing a fast and stable reference voltage.
摘要翻译:带隙基准电路包括与连接到智能钳位电路的电压产生电路连接的电流产生电路和连接到电流产生电路和电压产生电路的放电电路。 放电电路最初在电流和电压产生电路中释放电位以改善重复性。 然后,当前发电电路中的启动电路在大约电源电压下初始化参考输出,以提高输出信号的速度和稳定时间。 电流产生电路将电流输出到电压产生电路,其将具有温度+ T C C的正函数的电流转换为参考电压。 智能钳位电路进一步产生具有温度-T T C的负功能和负载电阻的钳位电压。 钳位电压和负载电阻跨越参考电压施加,特别是在高温下和启动期间快速降低参考电压,从而产生快速稳定的参考电压。
摘要:
According to one exemplary embodiment, a buffer circuit is configured to receive a supply voltage and an input reference voltage, the buffer circuit has a first FET operating in saturation region where the source of the first FET is coupled to the output reference voltage. The first FET can be configured, for example, as an open-loop voltage follower and, by way of example, a first resistor can be used to couple the source of the first FET to the output reference voltage. A tracking circuit is connected to the buffer circuit. The tracking circuit comprises a second FET also operating in saturation region where the drain of the second FET is coupled to the output reference voltage. Both the first and second FETs can be, for example, depletion mode transistors.
摘要:
A non-volatile memory read circuit having adjustable current sources to provide end of life simulation. A flash memory device comprising a reference current source used to provide a reference current for comparison to the current of a memory cell being read, includes an adjustable current source in parallel with the memory cell being read, and an adjustable current source in parallel with the reference current source. The current from the memory cell, reference current source, and their parallel adjustable current sources are input to cascode circuits for conversion to voltages that are compared by a sense amplifier. The behavior of the cascode circuits and sense amplifier in response to changes in the memory cell and reference current source may be evaluated by adjusting the adjustable current sources so that the combined current at each input to the sense amplifier simulates the current of the circuit after aging or cycling.
摘要:
A method for providing a modified threshold voltage distribution for a dynamic reference array in a flash memory cell array. The dynamic reference array and an associated core memory cell array are programmed using two different programming processes to produce different Vt distributions for the dynamic reference array and the core memory cell array. The dynamic reference array is programmed using a finer program pulse to achieve a smaller distribution width, thus enhancing the read margin for the memory cell array. The finer pulse may be of shorter duration or of smaller amplitude. The finer programming process may be applied to one or more threshold voltage distributions (states) in the memory cell array.
摘要:
A memory system has the capability to adjust a program or erase voltage if the time to program or erase is excessive. The memory system comprises at least a memory cell, a voltage value storage device, a voltage source, and a voltage adjustment circuit. The voltage value storage device stores a voltage value. The voltage source receives and converts the voltage value into a voltage. The voltage source applies the voltage to at least one memory cell. The voltage adjustment circuit is also coupled to receive the stored voltage value. The voltage adjustment circuit determines the time required to program or erase at least one memory cell using the voltage value. If the time to program or erase at least one memory cell is excessive, the voltage adjustment circuit increments the voltage value stored in the voltage value storage device.
摘要:
According to an aspect of the embodiments, the block decoder control circuits which drive the pass transistors for the word lines for a flash memory array are driven with a control voltage that is regulated to be one enhancement transistors threshold voltage higher than the highest voltage that is actually driven onto the word lines. According to another aspect of some of the embodiments, the block decoder control circuits are implemented with transistors having a very low threshold voltage. According to yet another aspect of some of the embodiments, a special series connection is used to prevent any leakage current through the block decoder control circuit from the high voltage generating charge pumps which might otherwise result from the use of low threshold voltage transistors. In the special series connection, any leakage current occurs from the supply voltage source rather than from the high voltage generating charge pumps. According to still another aspect of some of the embodiments, a special gate connection applies an intermediate bias voltage higher than a positive supply voltage onto the gates of the unselected block decoder transistors that are connected to a high-voltage. Several embodiments are presented which combine the regulated control voltage aspect and various combinations of the other aspects.
摘要:
A method for a memory redundancy, including a memory array typically having a plurality of columns (e.g., bit lines) of memory cells, and identifying a particular (e.g., defective) column of the memory array and further defining a redundancy window by selecting a group of adjacent columns including the defective column. The number of columns in the group of selected columns may be equal to the number of columns in a redundancy array that is coupled to the memory array. The redundancy array is used for storing information that would have been otherwise stored in the memory cells in the redundancy window. The selected group includes at least one column on one side of the defective column and another column on the other side of the defective column. Typically, there will be multiple columns on each side of the defective column.
摘要:
A non-volatile memory and method for continuously regulating an output of a charge pump of the non-volatile memory for long periods of time at a target output voltage.
摘要:
A capacitor divider includes two capacitors coupled in series between two voltage sources. A first capacitor is a floating gate capacitor having one plate being the control gate of a floating gate transistor structure and the other plate being a source, drain, and channel region of the floating gate transistor structure. The capacitive divider has the advantage of having at least one floating gate capacitor, can be implemented in a voltage regulator, and works for a variety of voltages across the capacitors.