Sandisk Technologies Inc.

Steve Choi

Jongmin Park

Jonathan Huynh

Sung-En Wang

Qui V Nguyen

Emilio Yero

Xiaofeng Zhang

Gyusung Park

Jiang Yin

Apparatuses and techniques are described for calibrating a negative voltage source. A ground voltage is applied to a multi-stage amplifier from the negative voltage source while an offset voltage measurement (OVM) is made at the output of the multi-stage amplifier. The OVM is recorded and subsequently used by a calibration circuit when the negative voltage source applies a range of negative voltages to the input of the multiple stage amplifier. The calibration circuit subtracts the OVM from measurements obtained at the output of the multi-stage amplifier to obtain corrected measurements, and uses the corrected measurements to calibrate the negative voltage source, e.g., by adjusting a relationship between digital values input to the negative voltage source and the output voltages.

Accurate self-calibrated negative to positive voltage conversion circuit and method

Techniques and circuitry are presented for more rapidly and accurately obtaining a temperature code (TCO) on an integrated circuit. A comparison voltage is ramped up and two counts are determined concurrently, a first count on how many clock cycles for the comparison voltage to ramp up from a low reference voltage to a proportional to absolute temperature (PTAT) and a second count for the number of clock cycles for the comparison voltage to go from the low reference voltage to a high reference voltage. The TCO value is then obtained by using the second count in a post-processing calibration to adjust the first count. An initial calibration can also be included when the circuit is powered up.

Temperature code circuit with single ramp for calibration and determination

Methods for controlling a ramp rate of an output voltage derived from one or more charge pumps and reducing variation in the ramp rate due to process, voltage, and temperature (PVT) variations are described. In some embodiments, the ramp rate of the output voltage from one or more charge pumps may be controlled using a ramp rate control circuit that uses a digital counter to adjust (or step up) the output voltage from the one or more charge pumps based on a ramp rate schedule. The ramp rate schedule may specify varying output voltage levels for the one or more charge pumps during a time period in which the output voltage charges up from a first voltage to a second voltage greater than the first voltage.

Digital ramp rate control for charge pumps

A circuit for providing a plurality of clock signals of differing frequencies includes: a phase locked loop section including a first voltage controller oscillator, connected to receive a reference clock value and generate therefrom a first voltage level, wherein the first voltage controller oscillator receives the first voltage level and generates therefrom a first clock signal; and one or more second voltage controller oscillators, each connected to receive the first voltage level, a corresponding trim value and a corresponding control voltage and derive therefrom a corresponding second clock signal.

Multi-clock generation through phase locked loop (PLL) reference

To maintain stability of memory array operations, a supplemental current can supply a common source line of a memory array so that the combined current from the memory array and supplemental current is at least a minimum regulation current level. When enabled for sensing operations, a driver circuit maintains the common source line's voltage level. A current subtractor circuit determines the difference between a reference current and a current proportional to the current flowing from the array, where the reference current is proportional to the minimum regulation current. The difference current is then mirrored by a self-adjusting current loop and supplied to the common source line to maintain its current level.

Self-adjusting regulation current for memory array source line

A charge pump is regulated based up its output level. The regulation circuitry adjusts the frequency of the pump's clock based on feedback from pump's output. The pump's clock signal is generated by an oscillator whose frequency depends on a reference voltage level. The reference voltage level is dependent upon a regulation signal. In an example, a transistor whose gate is controlled by the regulation level is part of a series of elements in voltage divider, where the reference value is taken from a node of the divider.

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Danville, CA, United States of America

Steve Choi