The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 2015
Filed:
Jun. 18, 2013
Texas Instruments Incorporated, Dallas, TX (US);
David H. Elwart, II, Sachse, TX (US);
Vikas Suma Vinay, Dallas, TX (US);
Christopher M. Graves, Sherman, TX (US);
Baher S. Haroun, Allen, TX (US);
TEXAS INSTRUMENTS INCORPORATED, Dallas, TX (US);
Abstract
Self-grounded circuitry () includes a signal channel conducting an output voltage (V). A charge pump () powered by a reference voltage (V) produces a control voltage (V). The control signal is at a low level if the reference voltage is low and is boosted to a high level if the reference voltage is high. A ground switch circuit () includes a depletion mode transistor (MP) having a source coupled to the output voltage, a gate coupled to the control voltage, and a drain coupled to ground. The transistor includes a well region (-) and a parasitic substrate diode (D-). A negative voltage protection circuit (-) includes a depletion mode first protection transistor (MP-) having a drain coupled to the well region, a source coupled to a source of a depletion mode second protection transistor (MP-) having a drain coupled to the output voltage, the first and second protection transistors each having a gate coupled to the control voltage, and also includes a diode (MN) coupled to charge the well region from the control voltage conductor to prevent distortion of the output voltage.