Data error measuring circuit for semiconductor memory apparatus

1. A data error measuring circuit for a semiconductor memory apparatus comprising:

a data error correction unit configured to compare first and second data with first and second parity data and to generate first and second corrected data, respectively;

a data selection unit configured to output the first and second data or the first and second corrected data as first and second selected data in response to a test selection signal; and

a test result output unit configured to compare bits of the first and second selected data with bits of the first and second parity data in response to the test selection signal to output a test result signal, the test result output unit including:

a first comparison section configured to detect an error in the first selected data and the first parity data in response to the test selection signal, and output the detection result as a first comparison signal;

a second comparison section configured to detect an error in the second selected data and the second parity data in response to the test selection signal, and output the detection result as a second comparison signal; and

a test result output section configured to output the test result signal in response to the first comparison signal and the second comparison signal when a read command is input.

2. The data error measuring circuit of claim 1 , wherein the data selection unit includes:

a first switch unit configured to output the first and second corrected data as the first and second selected data in response to the test selection signal; and

a second switch unit configured to output the first and second data as the first and second selected data in response to the test selection signal, and wherein the first and second selected data are output from a node at which an output terminal of the first switch unit and an output terminal of the second switch unit are connected to each other.

3. The data error measuring circuit of claim 2 , wherein either the first switch or second switch unit is selectively turned on according to the test selection signal.

4. The data error measuring circuit of claim 1 , wherein the first selected data has a plurality of the bits and the first parity data has a plurality of the bits, and wherein the first comparison section includes:

a data bit comparison section configured to compare the bits of the first selected data;

a parity bit comparison section configured to compare the bits of the first parity data, a parity option section configured to output an output signal of the parity bit comparison section in response to the test selection signal; and

a signal combining section configured to combine an output signal of the data bit comparison section and the output signal of the parity option section, to output the first comparison signal.

5. The data error measuring circuit of claim 4 , wherein, if the bits of the first selected data are all at the high level, the data bit comparison section is configured to output a low-level signal.

6. The data error measuring circuit of claim 4 , wherein, if the bits of the first parity data are all at the low level, the parity bit comparison section is configured to output a low-level signal.

7. The data error measuring circuit of claim 4 , wherein the parity option section is configured to output an output signal of the parity bit comparison section or a signal at a predetermined level in response to the test selection signal.

8. The data error measuring circuit of claim 1 , wherein the second selected data has a plurality of the bits and the second parity data has a plurality of the bits, and wherein the second comparison section includes:

a data bit comparison section configured to compare the bits of the second selected data;

a parity bit comparison section configured to compare the bits of the second parity data, a parity option section configured to output an output signal of the parity bit comparison section in response to the test selection signal; and

a signal combining section configured to combine an output signal of the data bit comparison section and the output signal of the parity option section, and output a second comparison signal.

9. The data error measuring circuit of claim 8 , wherein, if the bits of the second selected data are all at the high level, the data bit comparison section is configured to output a low-level signal.

10. The data error measuring circuit of claim 8 , wherein, if the bits of the second parity data are all at the low level, the parity bit comparison section is configured to output a low-level signal.

11. The data error measuring circuit of claim 8 , wherein the parity option section is configured to output an output signal of the parity bit comparison section or a signal at a predetermined level in response to the test selection signal.

12. The data error measuring circuit of claim 1 , wherein the test result output section includes:

a signal combining section configured to receive the first comparison signal and the second comparison signal;

first and second output control sections are configured to output an output signal of the signal combining section as the test result signal when the read command is input; and

a signal generating section configured to output the output signals of the first and second output control section as the test result signal.

13. The data error measuring circuit of claim 12 , wherein the first output control section is configured to output the output signal of the signal combining section as the test result signal in response to a read status signal.

14. The data error measuring circuit of claim 12 , wherein the second output control section is configured to output the output signal of the signal combining section as the test result signal in response to a read status signal.

15. The data error measuring circuit of claim 12 , wherein the signal generating section includes:

a first transistor that has a source connected to a ground terminal, and a gate, to which an output signal of the first output control section is input; and

a second transistor that has a source, to which an external voltage is supplied, a gate, to which an output signal of the second output control section is input, and a drain connected to a drain of the first transistor, and the test result signal is output from a node at which the first transistor and the second transistor are connected to each other.