Circuit and method for testing a memory device

A voltage generator coupled to a capacitor, the voltage generator comprising:

• means to provide a predetermined voltage at an output coupled to the capacitor;
• at least a first integrated circuit transistor fabricated with an appropriate width to generate a normal drive current from a supply of electrical potential through the output when the predetermined voltage is provided at the output, wherein the normal drive current is used to operate a plurality of memory cells;
• and
• at least a second integrated circuit transistor fabricated with an appropriate width to generate a test drive current from the supply of electrical potential through the output when the predetermined voltage is provided at the output, wherein the test drive current is used to test the memory cells for current leakage, such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a voltage divider having a voltage divider output connected to a capacitor;
• a first pass transistor coupled in series between the voltage divider output and a generator output, wherein the first pass transistor is fabricated with an appropriate width such that an actuated first pass transistor provides a normal drive current;
• and
• a second pass transistor coupled in series between the voltage divider output and the generator output, wherein the second pass transistor is fabricated with an appropriate width such that an actuated second pass transistor provides a lower test drive current such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a source of electric potential;
• a first pass transistor coupled in series between the source of electric potential and a generator output, wherein the first pass transistor is fabricated with an appropriate width such that an actuated first pass transistor provides a normal drive current;
• and
• a second pass transistor coupled in series between the source of electric potential and the generator output, wherein the second pass transistor is fabricated with an appropriate width such that an actuated second pass transistor provides a lower test drive current, and wherein a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a power supply connection;
• a control signal input;
• a generator output connected to the capacitor;
• a first generator circuit operably connected to the power supply connection and to the control signal input, wherein the first generator circuit produces a normal drive current and a predetermined voltage at the generator output upon receiving a normal control signal at the control signal input;
• and
• a second generator circuit operably connected to the power supply connection and to the control signal input, wherein the second generator circuit produces a test drive current and the predetermined voltage at the generator output upon receiving a test control signal at the control signal input such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a power supply connection;
• a control signal input;
• a generator output connected to the capacitor;
• a first voltage divider coupled to the power supply connection, wherein the first voltage divider has a first voltage divider output;
• a first pass through transistor coupled in series between the first voltage divider output and the generator output, wherein:
• a gate of the first pass through transistor is coupled to the control signal input such that a normal control signal at the control signal input actuates the first pass through transistor;
• and
• an actuated first pass through transistor provides a normal drive current at the generator output;
• a second voltage divider coupled to the power supply connection, wherein the second voltage divider has a second voltage divider output;
• and
• a second pass through transistor coupled in series between the second voltage divider output and the generator output, wherein:
• a gate of the second pass through transistor is coupled to the control signal input such that a test control signal at the control signal input actuates the second pass through transistor;
• and
• an actuated second pass through transistor provides a test drive current at the generator output such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a power supply connection;
• a control signal input;
• a generator output connected to the capacitor;
• a voltage divider having a voltage divider output;
• a first pass transistor coupled in series between the voltage divider output and the generator output, wherein the first pass transistor is fabricated with an appropriate width such that an actuated first pass transistor provides a normal drive current;
• and
• a second pass transistor coupled in series between the voltage divider output and the generator output, wherein the second pass transistor is fabricated with an appropriate width such that an actuated second pass transistor provides a test drive current such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a control signal input;
• a generator output connected to the capacitor;
• a source of electric potential;
• a first pass transistor coupled in series between the source of electric potential and the generator output, wherein the first pass transistor is fabricated with an appropriate width such that an actuated first pass transistor provides a normal drive current;
• and
• a second pass transistor coupled in series between the source of electric potential and the generator output, wherein the second pass transistor is fabricated with an appropriate width such that an actuated second pass transistor provides a test drive current such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a first voltage generator adapted for providing a normal drive current during normal operation, the first voltage generator including:
• a first voltage divider having a first n-channel transistor coupled to a first p-channel transistor in a voltage divider configuration to form a first voltage divider output, wherein the first n-channel transistor and the first p-channel transistor are fabricated with an appropriate width to provide the normal drive current;
• and
• a first pass transistor coupled in series between the first voltage divider output and a generator output, wherein the normal drive current flows through an actuated first pass transistor;
• and
• a second voltage generator adapted for providing a test drive current during at least a portion of a test mode, such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor, the second voltage generator including:
• a second voltage divider having a second n-channel transistor coupled to a second p-channel transistor in a voltage divider configuration to form a second voltage divider output, wherein the second n-channel transistor and the second p-channel transistor are fabricated with an appropriate width to provide the test drive current which is lower than the normal drive current;
• and
• a second pass transistor coupled in series between the second voltage divider output and the generator output, wherein the lower test drive current flows through an actuated second pass transistor.

A voltage generator coupled to a capacitor, the voltage generator comprising:

• a power supply connection;
• a control signal input;
• a generator output connected to the capacitor;
• a first generator circuit operably connected to the power supply connection and to the control signal input, wherein the first generator circuit produces a normal drive current at the generator output upon receiving a normal control signal at the control signal input, the first generator including:
• a first voltage divider having a first voltage divider output;
• and
• a first pass through transistor coupled in series between the first voltage divider output and the generator output, wherein a gate of the first pass through transistor is coupled to the control signal input such that the normal control signal actuates the first pass through transistor;
• and
• a second generator circuit operably connected to the power supply connection and to the control signal input, wherein the second generator circuit produces a test drive current at the generator output upon receiving a test control signal at the control signal input such that a voltage on the capacitor rapidly changes when a current leakage path is present due to a defect in the capacitor, the second generator circuit including:
• a second voltage divider having a second voltage divider output;
• and
• a second pass through transistor coupled in series between the second voltage divider output and the generator output, wherein a gate of the second pass through transistor is coupled to the control signal input such that the test drive control signal actuates the second pass through transistor.