Quiescent current (IDDQ) indication and testing apparatus and methods

An electronic device comprising:

• a first ground node;
• a second ground node;
• a logic circuit having a logic ground output, wherein the logic ground output is electrically coupled to the first ground node;
• a switching element electrically coupled between the first ground node and the second ground node, wherein the switching element is configurable in an electrically non-conductive state when the electronic device is in a quiescent current (IDDQ) evaluation state, and the switching element is configurable in an electrically conductive state when the electronic device is not in the IDDQ evaluation state;
• and
• an IDDQ evaluation circuit electrically coupled between the first ground node and the second ground node, wherein, when the electronic device is in the IDDQ evaluation state, the IDDQ evaluation circuit is configured to provide a first output signal when an IDDQ indicating voltage across the first and second ground nodes exceeds a reference voltage, wherein the IDDQ evaluation circuit comprises:
• a resistive element electrically coupled between the first ground node and the second ground node;
• and
• a comparison circuit having a first input electrically coupled to the first ground node, a second input electrically coupled to the second ground node, a third input coupled to a reference node, and an output, wherein the IDDQ indicating voltage presents itself across the first and second inputs, and the reference voltage presents itself across the third and second inputs, and wherein the comparison circuit is configured to compare the reference voltage with the IDDQ indicating voltage, and to provide the first output signal at the output when the IDDQ indicating voltage exceeds the reference voltage.

An electronic device comprising:

• a first ground node;
• a second ground node;
• a logic circuit having a logic ground output, wherein the logic ground output is electrically coupled to the first ground node;
• a switching element electrically coupled between the first ground node and the second ground node, wherein the switching element is configurable in an electrically non-conductive state when the electronic device is in a quiescent current (IDDQ) evaluation state, and the switching element is configurable in an electrically conductive state when the electronic device is not in the IDDQ evaluation state;
• an IDDQ evaluation circuit electrically coupled between the first ground node and the second ground node, wherein, when the electronic device is in the IDDQ evaluation state, the IDDQ evaluation circuit is configured to provide a first output signal when an IDDQ indicating voltage across the first and second ground nodes exceeds a reference voltage;
• a reference voltage generation circuit configured to produce the reference voltage;
• and
• a temperature detection circuit electrically coupled to the reference voltage generation circuit, and configured to provide a second output signal that indicates whether a device temperature does or does not exceed a pre-determined temperature threshold, and wherein
• the reference voltage generation circuit is further configured to produce the reference voltage at a first level when the second output signal indicates that the device temperature does not exceed the pre-determined temperature threshold, and to produce the reference voltage at a second level that is higher than the first level when the second output signal indicates that the device temperature does exceed the pre-determined temperature threshold.

An electronic device comprising:

• a first ground node;
• a second ground node;
• a logic circuit having a logic ground output, wherein the logic ground output is electrically coupled to the first ground node;
• a switching element electrically coupled between the first ground node and the second ground node, wherein the switching element is configurable in an electrically non-conductive state when the electronic device is in a quiescent current (IDDQ) evaluation state, and the switching element is configurable in an electrically conductive state when the electronic device is not in the IDDQ evaluation state, wherein the switching element is responsive to a control signal to place the switching element in the electrically conductive state or the electrically non-conductive state;
• an IDDQ evaluation circuit electrically coupled between the first ground node and the second ground node, wherein, when the electronic device is in the IDDQ evaluation state, the IDDQ evaluation circuit is configured to provide a first output signal when an IDDQ indicating voltage across the first and second ground nodes exceeds a reference voltage;
• and
• an IDDQ test enable circuit electrically coupled to the switching element, wherein the IDDQ test enable circuit is configured to make a determination of whether or not the electronic device should enter the IDDQ evaluation state, and to produce the control signal in a manner that causes the switching element to be placed in the electrically non-conductive state when the determination is made that the electronic device should enter the IDDQ evaluation state.

A method for producing an indication of quiescent current (IDDQ) in an electronic device, the method comprising the steps of:

• setting a logic circuit of the electronic device to a test state, wherein a logic ground output of the logic circuit is electrically coupled to a first ground node of the electronic device, the logic circuit produces the IDDQ, and the IDDQ can flow between the first ground node and a second ground node;
• controlling a switching element of the electronic device into an electrically non-conductive state, wherein the switching element is electrically coupled across the first ground node and the second ground node of the electronic device;
• comparing, by a comparison circuit integrated within the electronic device, a reference voltage with an IDDQ indicating voltage across the first and second ground nodes while the switching element is in the electrically non-conductive state, wherein the IDDQ indicating voltage is related to the IDDQ that flows between the first ground node and the second ground node;
• and
• when the IDDQ indicating voltage exceeds the reference voltage, producing an output signal at a first external contact of the electronic device, wherein the output signal indicates that the IDDQ is relatively high.

A method for producing an indication of quiescent current (IDDQ) in an electronic device, the method comprising the steps of:

• setting a logic circuit of the electronic device to a test state, wherein a logic ground output of the logic circuit is electrically coupled to a first ground node of the electronic device;
• determining whether a device temperature exceeds a threshold;
• when the device temperature exceeds the threshold, establishing a reference voltage at a relatively high voltage level;
• when the device temperature does not exceed the threshold, establishing the reference voltage at a relatively low voltage level;
• controlling a switching element of the electronic device into an electrically non-conductive state, wherein the switching element is electrically coupled between the first ground node and a second ground node of the electronic device;
• comparing, by a comparison circuit integrated within the electronic device, the reference voltage with an IDDQ indicating voltage across the first and second ground nodes while the switching element is in the electrically non-conductive state;
• and
• when the IDDQ indicating voltage exceeds the reference voltage, producing an output signal at a first external contact of the electronic device, wherein the output signal indicates that the IDDQ is relatively high.