Active probe for measuring voltage at high impedances
AssigneeAteq
InventorThierry May
Life of this patent
Estimating the term…
Abstract
An active probe (1) for measuring a voltage across a high value impedance, the active probe (1) including: an impedance matching circuit (10) configured to have an input impedance at least 100 times higher than the impedance to be measured, and to deliver a low impedance signal at the output; a probe tip (6) configured to take a measurement and connected to the impedance matching circuit (10); a ground reference (G) connected to the impedance matching circuit (10); the impedance matching circuit (10) including, connected in cascade, at least one input circuit (14) and a non-inverting amplifier circuit (16) adapted to high impedance values.
Claims10
An active probe for measuring a voltage across a high-value impedance of at least 10 gigaohms (GΩ) of an electronic circuit, said probe comprising:
- an impedance matching circuit configured, on the one hand, to have an input impedance at least 100 times higher than the high-value impedance of the electronic circuit on which the voltage is measured and, on the other hand, to deliver a low impedance signal at an output of the impedance matching circuit;
- a probe tip configured to take a measurement and connected to said impedance matching circuit;
- a ground reference connected to said impedance matching circuit;
- and
- said impedance matching circuit comprising, in a cascade, at least one input circuit and a non-inverting amplifier circuit adapted to high impedance values;
- wherein the non-inverting amplifier circuit comprises:
- an operational amplifier having inverting and non-inverting inputs;
- a resistor arranged at the inverting input of said operational amplifier;
- and
- a guard ring surrounding the inverting and non-inverting inputs of said operational amplifier and, at least partially, the resistor at the inverting input of said operational amplifier.
Dependencies are inferred from the claim text.