Abstract: In a cordless power tool system, protection methods, circuits and devices are provided to protect against fault conditions within a battery pack that is operatively attached to a power tool or charger, so as to prevent internal or external damage to the battery pack or attached tool or charger. The exemplary methods, circuits and devices address fault conditions such as over-charge, over-discharge, over-current, over-temperature, etc.

Abstract: A battery monitoring device of a battery pack configured for powering a cordless power tool may include an integrated circuit connected to a microprocessor of the pack that is external to the integrated circuit, and which is connected to each of N battery cells of the pack. The integrated circuit may be configured to take, singly or sequentially, a sampled reading comprising one of an individual cell voltage or a total pack voltage for all cells in the pack. The sampled reading is filtered in the integrated circuit prior to being read by the microprocessor.

Abstract: A motor control module for a power tool includes a controller and a triac for controlling current to the given tool motor. The module includes a circuit within the controller for implementing a plurality of control methodologies related to synchronizing the module to the AC input signal, estimating average current flowing through the triac, compensating for amplifier offset to improve accuracy of current measurements in the module, and providing speed measurement and control for the tool motor using principles of hysteresis in a comparator of the controller. Additionally, the controller is configured to calibrate an oscillation calibration register therein.

Abstract: A battery monitoring device of a battery pack configured for powering a cordless power tool may include an integrated circuit connected to a microprocessor of the pack that is external to the integrated circuit, and which is connected to each of N battery cells of the pack. The integrated circuit may be configured to take, singly or sequentially, a sampled reading comprising one of an individual cell voltage or a total pack voltage for all cells in the pack. The sampled reading is filtered in the integrated circuit prior to being read by the microprocessor.

Abstract: A control scheme is provided for a power tool having a rotary shaft. The control scheme includes: monitoring parameters of a power tool during operation of the tool; evaluating a rotational condition of the tool about a longitudinal axis of the rotary shaft using a function defined as a linear combination of the monitored parameters; and initiating a protective operation to address the rotational condition of the tool based on an output of the function. In a simple form, the function is expressed in the form c0+c1*m1+c2*m2+ . . . +cn*mn, where (c0, c1, c2 . . . cn) are constants and (m1, m2 . . . mn) are the monitored parameters.

Abstract: An electronic system for entering and analyzing data relating to at least one attribute of an object includes a data entry means displaying a pictorial image of the object and providing a plurality of first indicia for identifying a location of the attribute in the object, and a plurality of additional indicia for identifying a parameter of the attribute. The data identifying the attribute are entered in the system when one of the first indicia in combination with at least one of the additional indicia are activated. A controlling means within the data entry means controls the data entry means in response to the entered data, which are processed by a processing means.

Abstract: An electronic system for entering and analyzing data relating to at least one attribute of an object includes a data entry means displaying a pictorial image of the object and providing a plurality of first indicia for identifying a location of the attribute in the object, and a plurality of additional indicia for identifying a parameter of the attribute. The data identifying the attribute are entered in the system when one of the first indicia in combination with at least one of the additional indicia are activated. A controlling means within the data entry means controls the data entry means in response to the entered data, which are processed by a processing means.