Isolation circuit with test mechanism and test method thereof

Abstract

An isolation circuit with a test mechanism and an isolation circuit test method, the isolation circuit with a test mechanism comprising: an isolation element and a test circuit. The isolation element transmits a signal at a data input end and a data output end when the signal received at a control input end has an enabled state, and isolates when the signal has a disabled state. The test circuit comprises: a multiplexer and a control circuit. In a shift operation state under a test mode, the control circuit controls the multiplexer to select a run input end to receive an isolation control signal with an enabled state and output it to the control input end. In a capture operation state under the test mode, the control circuit controls the multiplexer to select a test input end to receive a test signal with an enabled state or a disabled state and output it to the control input end. The control circuit determines whether the isolation element transmits a signal or isolates according to the signals at the data input end and the data output end.

Description

Technical Field

[0001] The invention relates to circuit testing technology, and in particular to an isolation circuit with a testing mechanism and a testing method thereof. Background Art

[0002] Before an integrated circuit (IC) is shipped out of the factory, a scan test sequence with high error coverage is often used to perform a scan test through a scan chain to eliminate defective chips in advance. This testing technology can detect most defects in the circuit.

[0003] In circuits designed with low power consumption, isolation components are generally added to isolate circuits in different power domains to prevent the circuits in the power-off area from affecting the circuits in the power-on area. However, since all power domains are required to be turned on in general scan tests, the isolation components are also set to the on state, and the scan chain is therefore unable to perform a complete test on the isolation components. Summary of the invention

[0004] In view of the problems in the prior art, an object of the present invention is to provide an isolation circuit with a testing mechanism and a testing method thereof, so as to improve the prior art.

[0005] The present invention includes an isolation circuit with a test mechanism, including: an isolation element and a test circuit. The isolation element includes a control input terminal, a data input terminal and a data output terminal, and is configured to perform signal transmission at the data input terminal and the data output terminal when the signal received at the control input terminal has an enable state, and to isolate the data input terminal and the data output terminal when the signal received at the control input terminal has a disable state. The test circuit includes: a multiplexer and a control circuit. The multiplexer includes an operation input terminal, a test input terminal and a control output terminal. In the shift operation state under the test mode, the control circuit controls the multiplexer to select the operation input terminal to receive the isolation control signal with the enable state, and outputs it to the control input terminal of the isolation element through the control output terminal. In the capture operation state under the test mode, the control circuit controls the multiplexer to select the test input terminal to receive the test signal with the enable state or the disable state, and outputs it to the control input terminal of the isolation element through the control output terminal, and then determines whether the isolation element performs signal transmission or isolation according to the signals at the data input terminal and the data output terminal.

[0006] The present invention also includes an isolation circuit testing method, which is applied to an isolation circuit with a testing mechanism, including: in a shift operation state under a test mode, the control circuit controls the multiplexer to select the operation input terminal included therein to receive the isolation control signal with an enabled state, and outputs it to the control input terminal of the isolation element through the control output terminal included therein; in a capture operation state under the test mode, the control circuit controls the multiplexer to select the test input terminal included therein to receive the test signal with an enabled state or a disabled state, and outputs it to the control input terminal of the isolation element through the control output terminal; the isolation element performs signal transmission at the data input terminal and the data output terminal when the signal received at the control input terminal has an enabled state; the isolation element performs isolation at the data input terminal and the data output terminal when the signal received at the control input terminal has a disabled state; and determines whether the isolation element performs signal transmission or isolation based on the signals at the data input terminal and the data output terminal.

[0007] The features, implementation and technical effects of the present disclosure are described in detail below with reference to the accompanying drawings as preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A block diagram showing a circuit system in one embodiment of the present invention; and

[0009] Figure 2 A flow chart of an isolation circuit testing method according to an embodiment of the present invention is shown.

[0010] Explanation of symbols

[0011] 100: Circuit system

[0012] 110: Isolation circuit

[0013] 120: External circuit

[0014] 130: First power supply area

[0015] 140: Second power supply area

[0016] 150: Isolation element

[0017] 160: Test Circuit

[0018] 170: Multiplexer

[0019] 180: Control circuit

[0020] 200: Isolation circuit test method

[0021] S210~S260: Steps

[0022] CI: Control input

[0023] CO: Control output

[0024] DI: data input terminal

[0025] DO: data output terminal

[0026] IC: Isolation control signal

[0027] OI: Operation input

[0028] SR1: First shift register

[0029] SR2: Second shift register

[0030] SR3: Third shift register

[0031] TI: Test input

[0032] TS: Test Signal DETAILED DESCRIPTION

[0033] An object of the present invention is to provide an isolation circuit with a test mechanism and a test method thereof, so as to perform a complete test on the isolation mechanism of an isolation element.

[0034] Please refer to Figure 1 . Figure 1 A block diagram of a circuit system 100 is shown in one embodiment of the present invention. The circuit system 100 includes an isolation circuit 110 with a test mechanism and an external circuit 120. The isolation circuit 110 is located in a first power supply region 130, and the external circuit 120 is located in a second power supply region 140. In more detail, the isolation circuit 110 and the external circuit 120 operate according to different power supplies.

[0035] The isolation circuit 110 includes an isolation element 150 and a test circuit 160 .

[0036] The isolation element 150 includes a control input terminal CI, a data input terminal DI, and a data output terminal DO. The isolation element 150 is configured to transmit signals between the data input terminal DI and the data output terminal DO when the signal received at the control input terminal CI has an enable state, and to isolate the data input terminal DI from the data output terminal DO when the signal received at the control input terminal CI has a disable state. In one embodiment, when the signal received at the control input terminal CI has a disable state, the isolation element 150 causes the data output terminal DO to continuously output a preset state.

[0037] In one embodiment, the isolation element 150 is a logic gate. For example, the isolation element 150 is, but not limited to, an AND gate. In this case, the enabled state is a high state, and the disabled state is a low state.

[0038] In more detail, when the signal received by the isolation element 150 at the control input terminal CI is high (enabled), the input of the data input terminal DI will be equal to the output of the data output terminal DO. When the signal received by the isolation element 150 at the control input terminal CI is low (disabled), the data output terminal DO will continue to output a low state regardless of the input of the data input terminal DI.

[0039] In practical applications, in the operation mode, the power supplies of the first power region 130 and the second power region 140 are both activated. In this case, the isolation element 150 in the isolation circuit 110 can be controlled by an enable signal to operate in a non-isolated state, and perform signal transmission at the data input terminal DI and the data output terminal DO.

[0040] However, in some use scenarios of the operation mode, the power of the first power region 130 will be turned off to form a power-off domain, while the power of the second power region 140 remains turned on to form a power-on domain. In such a situation, in order to prevent the circuit in the first power region 130 from outputting an unclear voltage, the isolation element 150 in the isolation circuit 110 can be controlled by a signal with a disabled state to operate in an isolation state, isolate the data input terminal DI and the data output terminal DO and output a preset state.

[0041] The isolation circuit 110 can perform a complete test on the isolation element 150 in the test mode through the setting of the test circuit 160. The structure and operation of the test circuit 160 will be described in more detail below.

[0042] The test circuit 160 includes a multiplexer 170 and a control circuit 180 .

[0043] The multiplexer 170 includes an operation input terminal OI, a test input terminal TI, and a control output terminal CO. The control circuit 180 is configured to control the multiplexer 170 to select different input terminals for signal transmission in different states of the test mode to achieve the purpose of testing.

[0044] In one embodiment, in order to test each circuit in the circuit system 100 , the circuit system 100 includes a scan chain (not shown), and the scan chain includes a plurality of shift registers to feed test data to the input end of each circuit.

[0045] For example, the test input terminal TI of the multiplexer 170 is electrically coupled to the first shift register SR1, the data input terminal DI of the isolation element 150 is electrically coupled to the second shift register SR2, and the data output terminal DO of the isolation element 150 is electrically coupled to the third shift register SR3 disposed in the external circuit 120. The first shift register SR1, the second shift register SR2, and the third shift register SR3 are all part of the scan chain, but other shift registers may be included between each shift register, and they do not have to be disposed adjacently.

[0046] In the shift operation state in the test mode, the scan chain will perform data shifting so that the data is shifted between the shift registers. At this time, the control circuit 180 controls the multiplexer 170 to select the operation input terminal OI to receive the isolation control signal IC with an enabled state, and outputs it to the control input terminal CI of the isolation element 150 through the control output terminal CO. Among them, the isolation control signal IC can come from other circuits (not shown) that operate in coordination with the control circuit 180, so as to generate the corresponding isolation control signal IC when the control circuit 180 controls the multiplexer 170 to select the operation input terminal OI.

[0047] Therefore, the control input terminal CI of the isolation element 150 receives the isolation control signal IC in the enabled state, so that the test data in the second shift register SR2 can be transmitted to the third shift register SR3 through the data input terminal DI and the data output terminal DO.

[0048] In the capture operation state in the test mode, the scan chain will perform data driving so that the data drives the corresponding circuit. At this time, the control circuit 180 controls the multiplexer 170 to select the test input terminal TI to receive the test signal TS with an enable state or a disable state, and outputs it to the control input terminal CI of the isolation element 150 through the control output terminal CO. In one embodiment, the test signal TS comes from the test data in the first shift register SR1.

[0049] Therefore, the control input terminal CI of the isolation element 150 will receive the test signal TS having an enabled state or a disabled state. By checking the data values ​​stored in the second shift register SR2 and the third shift register SR3 electrically coupled to the data input terminal DI and the data output terminal DO respectively, the signals of the data input terminal DI and the data output terminal DO can be compared to confirm whether the isolation element 150 correctly performs data signal transmission or isolation, thereby achieving the purpose of testing.

[0050] It should be noted that in the test mode, the shift operation state and the capture operation state are performed alternately until all test patterns have been fed into the scan chain.

[0051] The above description of the operation of the multiplexer 170 and the control circuit 180 is all for the test mode. In the operation mode, the control circuit 180 can continuously enable the multiplexer 170 to select the operation input terminal OI to receive the isolation control signal IC with an enable state or a disable state to perform normal data signal transmission and isolation mechanism.

[0052] In some technologies, the isolation element 150 can only test the data input terminal DI and the data output terminal DO, but cannot test whether the control input terminal CI of the isolation element 150 operates correctly. By setting the test circuit 160 in the isolation circuit 110 of the present invention, the control input terminal CI of the isolation element 150 can be tested to ensure that the isolation mechanism of the isolation element 150 operates normally.

[0053] Please refer to Figure 2 . Figure 2 A flow chart of an isolation circuit testing method 200 according to an embodiment of the present invention is shown.

[0054] In addition to the aforementioned apparatus, the present invention also discloses an isolation circuit testing method 200, which is applied to, for example (but not limited to): Figure 1 An embodiment of the isolation circuit testing method 200 is as follows: Figure 2 As shown, the following steps are included.

[0055] In step S210 , in the shift operation state under the test mode, the control circuit 180 controls the multiplexer 170 to select the included operation input terminal OI to receive the isolation control signal IC with an enabled state, and outputs it to the control input terminal CI of the isolation element 150 through the included control output terminal CO.

[0056] In step S220 , in the capture operation state under the test mode, the control circuit 180 controls the multiplexer 170 to select the included test input terminal TI to receive the test signal TS with an enabled state or a disabled state, and outputs it to the control input terminal CI of the isolation element 150 through the control output terminal CO.

[0057] In step S230 : it is determined whether the signal received by the isolation element 150 at the control input terminal CI is in an enabled state.

[0058] In step S240 , the isolation element 150 is enabled to perform signal transmission at the data input terminal DI and the data output terminal DO when the signal received at the control input terminal CI is in an enabled state.

[0059] In step S250 , the isolation element 150 isolates the data input terminal DI from the data output terminal DO when the signal received by the control input terminal CI is in a disabled state.

[0060] In step S260 : it is determined whether the isolation element performs signal transmission or isolation according to the signals at the data input terminal DI and the data output terminal DO.

[0061] It should be noted that the above implementation is only an example. In other embodiments, those skilled in the art can make changes without violating the concept of the present invention.

[0062] In summary, the isolation circuit with a test mechanism and the test method thereof in the present invention can perform a complete test on the isolation mechanism of the isolation element.

[0063] Although the embodiments of the present disclosure are described above, the embodiments are not intended to limit the present disclosure. Technicians in this technical field may make changes to the technical features of the present disclosure based on the explicit or implicit contents of the present disclosure. All these changes may fall within the scope of patent protection sought by the present disclosure. In other words, the scope of patent protection of the present disclosure shall be based on what is defined in the claims of this specification.

Claims

1. An isolation circuit with a test mechanism, comprising: an isolation element, comprising a control input terminal, a data input terminal and a data output terminal, configured to transmit signals between the data input terminal and the data output terminal when a signal received at the control input terminal has an enabled state, and to isolate the data input terminal from the data output terminal when the signal received at the control input terminal has a disabled state; and A test circuit comprising: a multiplexer comprising a run input terminal, a test input terminal and a control output terminal; and a control circuit; wherein in a shift operation state under a test mode, the control circuit controls the multiplexer to select the operation input terminal to receive an isolation control signal having the enable state, and outputs the signal to the control input terminal of the isolation element through the control output terminal; In a capture operation state under the test mode, the control circuit controls the multiplexer to select the test input end to receive a test signal having the enable state or the disable state, and outputs it to the control input end of the isolation element through the control output end, and then determines whether the isolation element performs signal transmission or isolation based on the signals at the data input end and the data output end.

2. The isolation circuit as claimed in claim 1, wherein the test input terminal of the multiplexer is configured to be electrically coupled to a first shift register in a scan chain to receive an input of the first shift register, and the data input terminal is configured to be electrically coupled to a second shift register in the scan chain to receive an input of the second shift register; The scan chain performs a data shift in the shift operation state, and performs a data drive in the capture operation state.

3. The isolation circuit as claimed in claim 2, wherein the data output terminal is electrically coupled to a third shift register disposed in an external circuit and included in the scan chain, and the data values ​​stored in the second shift register and the third shift register are actually used to determine whether the isolation element performs signal transmission or isolation.

4. The isolation circuit as claimed in claim 3, wherein the isolation circuit and the external circuit are respectively located in a first power region and a second power region; Wherein, in a non-isolated state in an operating mode, the first power region and the second power region are both enabled, and the control circuit controls the multiplexer to select the operating input terminal to receive the isolation control signal having the enabled state; In an isolation state in the operation mode, the first power region is disabled and the second power region is enabled, and the control circuit controls the multiplexer to select the operation input terminal to receive the isolation control signal having the disabled state. 5 . The isolation circuit as claimed in claim 1 , wherein the isolation element is a logic gate configured to output a preset state according to the disabled state when the signal received at the control input terminal has the disabled state.

6. A method for testing an isolation circuit, applied to an isolation circuit having a testing mechanism, comprising: In a shift operation state under a test mode, a control circuit controls a multiplexer to select a running input terminal included therein to receive an isolation control signal having a consistent enabling state, and outputs the signal to a control input terminal of an isolation element through a control output terminal included therein; In a capture operation state under the test mode, the control circuit controls the multiplexer to select a test input terminal included therein to receive a test signal having the enable state or a disable state, and outputs the test signal to the control input terminal of the isolation element through the control output terminal; When a signal received by the isolation element at the control input terminal has the enabling state, the isolation element performs signal transmission at a data input terminal and a data output terminal; enabling the isolation element to isolate the data input terminal and the data output terminal when the signal received at the control input terminal is in the disabled state; and The isolation element is judged whether to perform signal transmission or isolation according to the signals of the data input end and the data output end.

7. The isolation circuit testing method as claimed in claim 6, wherein the test input terminal of the multiplexer is configured to be electrically coupled to a first shift register in a scan chain to receive an input of the first shift register, and the data input terminal is configured to be electrically coupled to a second shift register in the scan chain to receive an input of the second shift register; The scan chain performs a data shift in the shift operation state, and performs a data drive in the capture operation state.

8. The isolation circuit testing method as claimed in claim 7, wherein the data values ​​stored in the second shift register and a third shift register included in the scan chain are actually used to determine whether the isolation element performs signal transmission or isolation.

9. The isolation circuit testing method according to claim 6, wherein the isolation circuit and an external circuit are respectively located in a first power supply region and a second power supply region, and the isolation circuit testing method further comprises: In a non-isolated state in an operating mode, the first power region and the second power region are both enabled, so that the control circuit controls the multiplexer to select the operating input terminal to receive the isolation control signal having the enabled state; In an isolation state in the operating mode, the first power region is disabled and the second power region is enabled, so that the control circuit controls the multiplexer to select the operating input terminal to receive the isolation control signal in the disabled state. 10 . The isolation circuit testing method as claimed in claim 6 , wherein the isolation element is a logic gate configured to output a preset state according to the disabled state when the signal received at the control input terminal has the disabled state.

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