| KEITHLEY INSTRUMENTS, INC. Patent applications |
| Patent application number | Title | Published |
|---|
| 20130113511 | DC-AC PROBE CARD TOPOLOGY - A DC-AC probe card for testing a DUT includes: a plurality of probe needles, each probe needle having a distal end for contacting said DUT; and a plurality of connection pathways operable to connect test instrumentation to the probe needles, wherein each connection pathway provides both a desired characteristic impedance for AC measurements and a guarded pathway for DC measurements between respective test instrument connections and probe needles. | 05-09-2013 |
| 20090273338 | ACTIVE AUTORANGING CURRENT SENSING CIRCUIT - A range-changing circuit for a measurement device having a desirable range includes an array of graduated impedances. And amplifier supplies an electrical voltage to at least one of the impedances of the array. A voltage sensing and limiting switch is provided in a feedback path of the amplifier. The switch limits said electrical voltage supplied to said at least one of the impedances in response to a sensed voltage that is sensed by the switch. An electrical voltage in the desirable range is developed across a different one of the impedances of the array based on an operation of the switch. | 11-05-2009 |
| 20090201822 | SWITCH MATRIX - A switch matrix for selectively connecting at least one of N signal inputs to at least one of M signal outputs, N and M being integers greater than two, includes a cluster of N input switches arranged about each of the M signal outputs resulting in at least M clusters of N input switches, each input switch having a switch input and a switch output, the switch outputs being connected to respective signal outputs, the clusters and the input switches in the clusters being arranged to permit adjacent switch inputs of adjacent clusters to be connected to form input switch nodes; and a steering switch for each of the signal inputs. The steering switch selectably connects a signal input to an input switch node, wherein the combination of the steering switches and the input switches are operable to connect a desired signal input to a desired signal output. | 08-13-2009 |
| 20090195261 | IMPEDANCE MEASURING INSTRUMENT - A measurement instrument for measuring the impedance of a device under test (DUT) includes a first source of either a voltage or a current and a second source of either a voltage or a current, wherein the first source is connectable in a first feedback relationship with the DUT and the second source is connectable in a second feedback relationship with both the DUT and the first source. The first and second sources are operated respectively as a current source responsive to the current through the DUT and a voltage source responsive to the voltage across the DUT or operated respectively as a voltage source responsive to the voltage across the DUT and a current source responsive to the current through the DUT. The second feedback relationship has a narrower bandwidth than the first feedback relationship. The resulting voltage across the DUT and the current through the DUT establish the measured impedance of the DUT. | 08-06-2009 |
| 20090048800 | TEST INSTRUMENT NETWORK - A test instrument network for testing a plurality of DUTs includes a plurality of communicating script processors, the script processors being adapted to execute computer code; and a plurality of measurement resources controllable by the script processors in response to executed computer code, the measurement resources being adapted to test the DUTs. Each script processor and measurement resource may be arbitrarily assigned by the controller to one of at least two groups, only one script processor being assigned to be a master script processor, any other script processor being a slave script processor and any group not including the master script processor being a remote group. The master script processor is exclusively authorized to initiate code execution on any script processor in a remote group. Any slave script processor is only able to initiate operation of measurement resources in it own group. When a particular script processor is executing computer code, the master script processor may not initiate execution of computer code on a member script processor in the group of the particular script processor and may not initiate operation of a member measurement resource in the group of the particular script processor. | 02-19-2009 |
| 20080303535 | MULTI-PIN CV MEASUREMENT - A method for measuring electrical parameters of a DUT having at least three terminals includes applying a first AC voltage to a first terminal; separately driving a second and a third terminal each to a virtual second AC voltage, each virtual voltage requiring a respective current; and measuring an electrical parameter of the DUT based on the first AC voltage and the second and third terminals each being at the virtual second AC voltage. | 12-11-2008 |
