Back to results
US 2019/0094301 A1Published application
Voltage level monitoring of an integrated circuit for production test and debug
AssigneeSTMicroelectronics International N.V.
InventorsVenkata Narayanan Srinivasan, Satinder Singh Malhi
Life of this patent
Estimating the term…
Abstract
A scan chain collects scan chain data from testing of a functional circuit and outputs a scan chain signal containing the scan chain data. A voltage monitor circuit operates to compare a supply voltage against a threshold and assert a reset signal when the supply voltage crosses the threshold. The reset signal resets a flip flop circuit whose output signal controls operation of a logic circuit that blocks passage of the scan chain signal to an integrated circuit probe pad and instead applies a constant logic signal to the probe pad indicating a voltage monitoring error.
Claims26
A circuit, comprising:
- a functional circuit;
- a scan chain coupled to the functional circuit and configured to collect scan chain data from testing of the functional circuit and output a scan chain signal containing the scan chain data;
- a voltage monitor circuit configured to compare a supply voltage to a threshold and assert a reset signal when the supply voltage crosses the threshold;
- a flip flop circuit configured to receive the reset signal and change a logic state of a flip flop output signal in response to assertion of the reset signal;
- and
- a logic circuit configured to block passage of the scan chain signal to an integrated circuit probe pad in response to the changed logic state of the flip flop output signal, wherein said integrated circuit probe pad is for probing by automated test equipment.
3 more elements
A method, comprising:
- generating a scan chain signal containing the scan chain data from testing of a functional circuit;
- comparing a supply voltage to a threshold and asserting a reset signal when the supply voltage crosses the threshold;
- and
- blocking passage of the scan chain signal to an integrated circuit probe pad in response to assertion of the reset signal, wherein said integrated circuit probe pad is for probing by automated test equipment.
1 more element
A circuit, comprising:
- a functional circuit;
- a scan chain coupled to the functional circuit and configured to collect scan chain data from testing of the functional circuit and output a scan chain signal containing the scan chain data;
- a first voltage monitor circuit configured to compare a first supply voltage to a first threshold and assert a first reset signal when the first supply voltage crosses the first threshold;
- a first flip flop circuit configured to receive the first reset signal and change a logic state of a first flip flop output signal in response to assertion of the first reset signal;
- a second voltage monitor circuit configured to compare a second supply voltage to a second threshold and assert a second reset signal when the second supply voltage crosses the second threshold;
- a second flip flop circuit configured to receive the second reset signal and change a logic state of a second flip flop output signal in response to assertion of the second reset signal;
- a first logic gate configured to logically combine the first and second flip flop output signals to generate a control signal;
- a second logic gate having a first input configured to receive the scan chain signal and a second input configured to receive the control signal;
- a multiplexer circuit having a first input configured to receive the scan chain signal and a second input configured to receive a signal output from the second logic gate;
- and
- an integrated circuit probe pad connected to an output of the multiplexer circuit, wherein said integrated circuit probe pad is for probing by automated test equipment.
8 more elements
A circuit, comprising:
- a functional circuit;
- a scan chain coupled to the functional circuit and configured to collect scan chain data from testing of the functional circuit and output a scan chain signal containing the scan chain data;
- a first voltage monitor circuit configured to compare a first supply voltage to a first threshold and assert a first reset signal when the first supply voltage crosses the first threshold;
- a first flip flop circuit configured to receive the first reset signal and change a logic state of a first flip flop output signal in response to assertion of the first reset signal;
- a second voltage monitor circuit configured to compare a second supply voltage to a second threshold and assert a second reset signal when the second supply voltage crosses the second threshold;
- a second flip flop circuit configured to receive the second reset signal and change a logic state of a second flip flop output signal in response to assertion of the second reset signal;
- and
- a multiplexer having a first input coupled to receive the scan chain signal, a second input coupled to receive a first coded signal and third input coupled to receive a second coded signal, said multiplexer controlled by a multibit select signal, said multibit select signal being decoded to cause selection between the first, second and third inputs for connection to the output coupled to the probe pad.
5 more elements
A method, comprising:
- generating a scan chain signal containing the scan chain data from testing of a functional circuit;
- comparing a first supply voltage to a first threshold and asserting a first reset signal when the first supply voltage crosses the first threshold;
- comparing a second supply voltage to a second threshold and asserting a second reset signal when the second supply voltage crosses the second threshold;
- and
- decoding logic states of the first and second reset signals to selectively choose between the scan chain signal, a first coded signal identifying that the first supply voltage crossed the first threshold and a second coded signal identifying that the second supply voltage has crossed the second threshold for output at an integrated circuit probe pad, wherein said integrated circuit probe pad is for probing by automated test equipment.
2 more elements
Dependencies are inferred from the claim text.