Protection circuit for general-purpose digital I/O lines
First Claim
1. An apparatus comprising circuitry for protecting the apparatus from destructive electrical conditions, the apparatus comprising:
- one or more input/output (I/O) lines; and
a first protection circuit coupled to an I/O line and operable to provide a primary level of protection for the I/O line, the first protection circuit comprising;
one or more diodes coupled to the I/O line for voltage clamping, and a current limiting device coupled to the I/O line and to the one or more diodes, wherein the current limiting device is operable to function as a low impedance device in a normal operating range and to function as a controlled power dissipater outside of the normal operating range.
5 Assignments
0 Petitions
Accused Products
Abstract
A protection circuit for protecting a device from destructive electrical conditions, such as ESD, over-voltage, and over-current, while keeping the output impedance of the device'"'"'s I/O lines to a minimum, and self-regulating power dissipation. The device may comprise a first protection circuit and a second protection circuit coupled to each of one or more I/O lines for providing a primary and a secondary level of protection, respectively, for the I/O lines. The first protection circuit of the device may combine the use of Schottky diodes for voltage clamping, with a current limiting device for self-regulating the power dissipation. The current limiting device may be operable to function as a small, low impedance resistor in a normal operating range and as a controlled power dissipater outside the normal operating range. The device may be a data acquisition device comprised in a data acquisition system.
46 Citations
36 Claims
-
1. An apparatus comprising circuitry for protecting the apparatus from destructive electrical conditions, the apparatus comprising:
-
one or more input/output (I/O) lines; and
a first protection circuit coupled to an I/O line and operable to provide a primary level of protection for the I/O line, the first protection circuit comprising;
one or more diodes coupled to the I/O line for voltage clamping, and a current limiting device coupled to the I/O line and to the one or more diodes, wherein the current limiting device is operable to function as a low impedance device in a normal operating range and to function as a controlled power dissipater outside of the normal operating range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A data acquisition device comprising circuitry to protect the device from destructive electrical conditions, the data acquisition device comprising:
-
one or more input/output (I/O) lines;
a first protection circuit coupled to an I/O line and operable to provide a primary level of protection for the I/O line, the first protection circuit comprising;
one or more Schottky diodes coupled to the I/O line for voltage clamping, and a current limiting device coupled to the I/O line and the one or more Schottky diodes, wherein the current limiting device is operable to function as a low impedance device in a normal operating range and to function as a controlled power dissipater outside of the normal operating range; and
a second protection circuit coupled to the first protection circuit and to the I/O line, wherein the second protection circuit is operable to provide a secondary level of protection for the I/O line, the second protection circuit comprising;
one or more pn-junction diodes coupled to the I/O line for voltage clamping. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
-
-
26. A data acquisition system, comprising:
-
a computer system for processing data obtained from one or more data acquisition processes; and
a data acquisition device coupled to the computer system for implementing the data acquisition processes and comprising circuitry to protect the device from destructive electrical conditions, the data acquisition device comprising;
one or more input/output (I/O) lines;
a first protection circuit coupled to an I/O line and operable to provide a primary level of protection for the I/O line, the protection circuit comprising;
one or more Schottky diodes coupled to the I/O line for voltage clamping, and a current limiting device coupled to the I/O line and the one or more Schottky diodes, wherein the current limiting device is operable to function as a low impedance device in a normal operating range and to function as a controlled power dissipater outside of the normal operating range; and
a second protection circuit coupled to the first protection circuit and to the I/O line, wherein the second protection circuit is operable to provide a secondary level of protection for the I/O line, the second protection circuit comprising;
one or more pn-junction diodes coupled to the I/O line for voltage clamping. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. A data acquisition device comprising circuitry to protect the device from destructive electrical conditions, the data acquisition device comprising:
-
one or more input/output (I/O) lines; and
a voltage monitoring unit operable to monitor a voltage level to be output via the one or more I/O lines;
wherein in said monitoring the output voltage, the voltage monitoring unit is operable to compare the output voltage to a desired output voltage to detect an over-current condition at an I/O line, wherein if the output voltage does not match the desired output voltage, the voltage monitoring unit is further operable to disable the output. - View Dependent Claims (36)
-
Specification