Abstract: The present invention is an ac-to-dc adaptor capable of driving the drill unit of a cordless drill. In the preferred embodiment, the adaptor has essentially the same look and feel as the battery pack normally used with a cordless drill. The adaptor contains conventional electronics to convert an ac line power input into a dc output sufficient to power the drill unit. The invention applies to other cordless tools as well.

Abstract: A means of integrating a microphone on the same integrated circuit die as other electronics in the system is disclosed. The structure uses solder bump technology to form a gap between an electrode on the silicon and another electrode. Charge is stored on the capacitor so when pressure from sound waves causes one electrode to flex, the capacitance and therefore the charge changes, causing signal current. The structure allows for area efficiency by allowing placement of active silicon circuitry under the microphone.

Abstract: The junction difference used for a band gap voltage reference is designed so that it has the needed temperature coefficient without amplification. This is accomplished by the appropriate choice of the number of junctions and the appropriate current densities. Only one polarity of bipolar transistors is required. The noise terms of each junction add in root mean square, rather than be linear amplification, resulting in a lower noise reference than other designs requiring only a single type of bipolar transistors. By using metal available in standard integrated circuit processes to form a resistor, a low temperature coefficient current source can easily be obtained.

Abstract: A means of high speed switching of a current source is accomplished by switching the source of the output current source transistor while employing circuitry to limit the movement of the source. The primary capacitance is the source diode, and the charge for this comes from a power rail. This results in both a reduction of and a good match of transients coupling to the output. Circuitry is also added to compensate for any current remaining when the current source is switched off.

Abstract: A means of high speed switching of a current source is accomplished by switching the source of the output current source transistor. The primary capacitance charging is the source diode, and the source of charge for this is a power rail. Circuitry is employed to limit the movement of the drain, resulting in both a reduction of and a good match of transients coupling to the output. Circuitry is also added to compensate for any current remaining when the current source is turned off.

Abstract: The junction difference used for a band gap voltage reference is designed so that it has the needed temperature coefficient without amplification. This is accomplished by the appropriate choice of the number of junctions and the appropriate current densities. Only one polarity of bipolar transistors is required. The noise terms of each junction add in root mean square, rather than by linear amplification, resulting in a lower noise reference than other designs requiring only a single type of bipolar transistors. By using metal available in standard integrated circuit processes to form a resistor, a low temperature coefficient current source can easily be obtained.

Abstract: An automatic meter reading uses information from existing dial or numeric display meters without any modification to the existing meter. Image detection is used to capture the meter image. Digital signal processing means are used to convert the image to characters by rotating, aligning, ordering, and comparing them to a stored character set as needed to represent the actual meter reading. Security based on a typical changes to the meter image can be provided by the same digital signal processing means. The results is the converted to binary form and transmitted using any of a wide variety of available means to a central base for storage, further analysis, and billing.

Abstract: The mixing valve used in the water fill system of a washing machine is moved from being located inside the washing machine to the water source, eliminating hoses, reducing manufacturing cost, and improving reliability.

Abstract: A linearized resistor for integrated circuits combines an N-type diffused resistor and a P-type diffused resistor. In one embodiment, the N-type and P-type diffused resistors are connected in series. In another embodiment, the N-type and P-type diffused resistors are connected in parallel. Two or more linearized resistors of the present invention may be used in IC circuits, such as voltage dividers, inverting amplifiers, single-ended operational amplifiers, and single-ended differential operational amplifiers. Linearized resistors of the present invention can be designed to have voltage coefficients smaller than conventional IC resistors having a single diffused resistor. As such, linearized resistors of the present invention can be designed to provide more uniform resistance over their operating voltage range than conventional IC resistors.

Abstract: A method and structure for automatically calibrating various paths within multi-channel analog integrated circuits is disclose. The invention calls for digital signal processing circuitry to correct for absolute gain differences in the multiple channels. A first reference channel is precision trimmed at manufacture and used by the digital processing circuitry as a reference for channel gain calibration. When the circuit is powered for use, the other channels are calibrated based on the trimmed and calibrated reference. The need for providing the circuitry to precision trim all other channels but one is avoided by this invention.

Abstract: An MOS current steering circuit (10) includes a current mirror arrangement with an input branch (12) and an output branch (16). In the input branch, the conduction channels of a current-limiting transistor (M1) and a current mirror input transistor (M3) are connected in series with each other between a first power supply voltage node V+ and one side of a current source (14). The other side of the current source and the gate of the current-limiting transistor are connected to another supply voltage node (V-). In the output branch, a current mirror output transistor (M4) has one side of its conduction channel connected as a current output node (D). The gates of the input and output transistors are connected together and to the common node (A) of the input transistor and the current source. A control transistor (M2) has its conduction channel connected between the other side of the output transistor and the first voltage supply node.

Abstract: Improved input offset voltage compensation of an amplifier (12) is achieved through the use of a servo loop which is added to electronic switch and capacitor offset compensation circuitry disposed in the input (14) and feedback (20) paths of the amplifier. A voltage approximately equal to the offset voltage is stored on a feedback capacitor (24) by operation of input reset (34), feedback shunt (22) and feedback reset (26) switches. An error correction voltage is then generated within the servo loop (40) to adjust for the residual offset produced by the operation of the input reset and feedback shunt switches as well as the finite gain of the amplifier.

Abstract: Offset voltage compensation is provided by a feedback capacitor (24) in a feedback loop (20). For periodically resetting the compensation, the signal input terminal (14) is grounded by an electronic MOSFET switch (34). Other such switches (22, 26) close the feedback loop (20) in front of the capacitor (24) and connect the output side of the capacitor (24) to ground for recharging. An input capacitor (30) for compensating the switching feed-through charge of the feedback loop switch (22) is connected between the input signal source (32) and the signal input terminal (14). The ratio of the inherent capacitances of the switches (22, 34) is equal to the capacitance ratio of their respective capacitors (24, 30). Also disclosed is a particularly advantageous method for operating the switches. For switching from the reset condition back to the transmit condition, first the feedback loop switch (22) is opened. Thereafter, the other switches (26, 31, 34) are operated.