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US RE40,549 E1Granted
Circuitry for a high voltage linear current sense IC
AssigneeInternational Rectifier Corporation
InventorJoseph Maggiolino
Life of this patent
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Abstract
A high voltage linear current sense integrated circuit includes a differential amplifier circuit that can amplify a differential signal in the hundreds of millivolts near the power supply. In addition, a constant current using opposing minus temperature coefficient MOSFETs is provided. Accordingly, an op-amp circuit is provided with an input offset voltage which is constant and insensitive to temperature changes. A circuit for generating a current reference on the high side of the current sense IC also is provided.
Claims8
A current sense integrated circuit, comprising:
- an amplifier circuit for receiving and amplifying a differential analog input signal at a first voltage level containing current sense information, wherein the amplifier circuit includes a circuit to minimize inherent offset voltage temperature offset drift, comprising a first pair of mirrored MOSFET's, such that the circuit has an offset voltage which is equal to the difference between the respective gate-to-source voltages of the MOSFET's and remains constant over temperature variations;
- a pulse width modulator circuit for converting the differential analog input signal to a pulse width modulated signal at the first voltage level;
- and
- a level shift circuit for converting the pulse width modulated signal from the first voltage level to a second voltage level;
- and
- a recovery circuit for reconstructing the analog input signal at the second voltage level. .
3 more elements
Dependencies are inferred from the claim text.