JP4894069B2 - DC module equipment - Google Patents

Description

  The present invention relates to a DC module device that expands the measurement / output range of a parametric measurement unit in an IC tester.

  If you want to output and measure a current that exceeds the output current range of a single PMU using a one-chip parametric measurement unit (PMU, also called a high-precision DC module), As shown in Reference 1, page 18, FIG. 5, the current output / measurement range can be expanded by inputting the PMU internal amplifier output to an external amplifier capable of outputting a large current.

  However, in the conventional method as described above, although the range of the output current / measurement current can be expanded by the external amplifier, the range of the output voltage / measurement voltage cannot be expanded.

Therefore, when expanding the output voltage range using the one-chip PMU, conventionally, the following two methods have been considered. The first method is to make the power supply follow the output and float. The second method is to use a PMU that originally has a wide output voltage range.
“Dual, pin-based parameter measurement unit”, [online], 2003, Maxim Japan, [searched November 6, 2006], Internet <URL: http: //datasheets.maxim-ic. com / jp / ds / MAX9951-MAX9952_en.pdf>

  However, in the case of the first method, it is necessary to prepare a floating power source for each PMU, which is very disadvantageous in terms of cost and mounting. In the case of a PMU including multiple channels, a restriction that “the output voltage difference between adjacent channels is a certain value or less” is imposed. Because the power supply is common in one package, even if you want to make a difference in the output between adjacent channels in the same chip, the adjacent pins (odd / even pins) have the same range of voltages. It is because it can output only.

  On the other hand, in the case of the second method, if the desired output voltage range product does not exist, there is a possibility that it becomes a customized custom product, which is disadvantageous in terms of development time, cost, unit price, and the like.

  In view of such problems, the present invention provides a DC module device that expands not only the output current / measurement current range but also the output voltage / measurement voltage range while maintaining the convenience of the existing one-chip PMU. For the purpose.

In order to solve the above-described problem , a DC module device according to the present invention includes an internal resistor through which an input signal to the device under test flows, and an internal differential amplifier that can detect a current value from a potential difference between both ends of the internal resistor. In the DC module device for expanding the measurement / output range of the parametric measurement unit having a voltage receiving unit for receiving the voltage of the output signal coming from the device under test, this device further includes an external amplifier for amplifying the voltage of the input signal A current sense resistor through which the amplified input signal flows, an external differential amplifier that converts the potential difference between both ends of the current sense resistor to a ground-reference potential difference, and an input signal that flows through the internal resistor is input to the device under test Select the potential difference across the internal resistor and apply it to the internal differential amplifier, and the amplified input signal flowing through the current sense resistor is A first switch that selects and supplies a ground-reference potential difference to the internal differential amplifier when it is input to the device, and a voltage sense amplifier that amplifies the voltage of the output signal from the device under test and supplies it to the voltage receiver When the first switch selects the potential difference across the internal resistor, the voltage sense amplifier gain is 1, and when the first switch selects the ground-reference potential difference, the voltage sense amplifier gain is ( 1 / gain of the external amplifier).

  The external amplifier can amplify the current of the input signal.

  The DC module device according to the present invention further includes an additional current sense resistor that is connected in parallel to the above-described current sense resistor and through which an amplified input signal selected exclusively from the current sense resistor flows, and a current sense resistor or an additional current. A third switch that provides the external differential amplifier with a potential difference between both ends selected exclusively among the sense resistors may be included. As a result, when a high voltage is applied, it is also possible to perform current application and measurement with a wide dynamic range.

  According to the present invention, by adding various external circuits to the existing PMU, not only the output current / measurement current range but also the output voltage / measurement voltage range can be maintained while maintaining the convenience of the one-chip PMU. It becomes possible to enlarge.

  Next, an embodiment of a DC module device according to the present invention will be described in detail with reference to the accompanying drawings. In the figure, elements not directly related to the present invention are not shown. Similar elements are denoted by the same reference numerals.

(First embodiment of the present invention)
FIG. 1 is a circuit diagram showing a first embodiment of a DC module device according to the present invention. The DC module device 10 is included, for example, in pin electronics (relay board) mounted on a test head of an IC tester that performs an electrical test of a device under test (DUT) 12. The DC module device 10 provides an input signal to the device under test 12 in a current range larger than the rated current range, and a parametric measurement unit 14 used when a test is performed by giving an input signal to the device under test 12 in the rated current range. When the test is carried out, it is composed of various additional circuits 16, 18, 20 used in addition to the parametric measurement unit 14.

  The parametric measurement unit 14 includes an internal amplifier 22 that amplifies an input signal, an internal resistor 24 through which the amplified input signal flows, an internal differential amplifier 26 that detects a current value from a potential difference between both ends of the resistor, and a device under test. 12 includes a switch SW2 and a measurement output amplifier 28 as a voltage receiving unit that receives the voltage of the output signal coming from 12.

  As already described, the parametric measurement unit 14 is used when a test is performed by applying an input signal to the device under test 12 in the rated current range. At this time, the switch SW4 for supplying the output signal from the parametric measurement unit 14 to the device under test 12 is turned on, and the switch SW5 for supplying the output signal from the additional circuits 16 and 18 to the device under test 12 is turned off. .

  On the other hand, when a test is performed by giving an input signal to the device under test 12 in a current range larger than the rated current range, since the additional circuits 16 and 18 are used, the switch SW4 is turned off and the switch SW5 is turned on. The additional circuit 16 includes an external amplifier 30. The feature of the present invention is that the external amplifier 30 can amplify not only the current of the input signal but also the voltage as shown in FIG. The input signal having the voltage amplified by the external amplifier 30 flows through the current sense resistor R1 included in the subsequent additional circuit 18.

  The additional circuit 18 includes an external differential amplifier 32 that converts a potential difference between both ends of the current sense resistor R1 into a GND-reference potential difference. The reason why the external differential amplifier 32 is necessary is that the output voltage of the external amplifier 30 may exceed the power supply voltage Vcc of the parametric measurement unit 14, and the potential at both ends of the current sense resistor R1 is input to the parametric measurement unit 14 as it is. This is because the common potential needs to be converted between the outside and inside. For example, the output voltage of the internal amplifier 22 is 5V, the power supply voltage Vcc = 8V, and the gain of the external amplifier 30 is doubled. Then, the output voltage of the external amplifier 30 becomes 10V. In this case, if there is no external differential amplifier 32, the parametric measurement unit 14 is supplied with a voltage based on 10 V applied to both ends of the current sense resistor R1. However, since 10V exceeds the power supply voltage 8V of the parametric measurement unit 14, if such a voltage is input, the parametric measurement unit 14 may be destroyed. For this reason, an external differential amplifier 32 is provided for converting the potential difference between both ends of the current sense resistor R1 into a GND reference potential difference.

  The parametric measurement unit 14 further includes a first switch SW3. The first switch SW3 selects a potential difference between both ends of the internal resistor 24 when an input signal flowing through the internal resistor 24 is input to the device under test 12, that is, when the switch SW4 is on and the switch SW5 is off. To the internal differential amplifier 26. That is, in FIG. 1, the switch SW3 is in contact with the right terminal. On the other hand, when an external input signal having an amplified voltage flowing through the current sense resistor R1 is input to the device under test 12, that is, when the switch SW4 is off and the switch SW5 is on, the external differential amplifier 32 Is selected and supplied to the internal differential amplifier 26. That is, all the switches SW3 are in contact with the left terminal. When the switch SW1 comes into contact with the upper terminal, either a small current range or a large current range can be obtained. In addition, when the switch SW2 is in contact with the upper terminal, either a small current range or a large current range can be measured.

  The DC module device 10 that expands the measurement / output range of the parametric measurement unit 14 in FIG. 1 further includes an additional circuit 20. The additional circuit 20 amplifies the voltage of the output signal from the device under test 12. In addition, a voltage sense amplifier 34 which is supplied to the measurement output amplifier 28 via the switch SW2 connected to the lower terminal is included. When the switch SW1 is connected to the lower terminal, the output voltage sensed by the voltage sense amplifier 34 is fed back to the internal amplifier 22.

  The additional circuit 20 further includes a second switch SW6. This switch SW6 contacts the lower terminal when the first switch SW3 contacts the right terminal and selects the potential difference across the internal resistor 24, and the gain of the voltage sense amplifier 34 is set to 1. . At this time, it goes without saying that the switch SW4 is on and the switch SW5 is off. On the other hand, when the first switch SW3 contacts the left terminal to select the GND reference potential difference, the switch SW6 contacts the upper terminal and performs voltage division by the resistor R2, thereby providing a voltage sense amplifier. 34 is defined as (1 / gain of the external amplifier 30). At this time, it goes without saying that the switch SW4 is off and the switch SW5 is on.

  The reason why the voltage sense amplifier 34 employs a configuration in which the gain can be switched by the second switch SW6 is the same as the reason why the external differential amplifier 32 is provided. That is, the output voltage of the voltage sense amplifier 34 may exceed the power supply voltage Vcc of the parametric measurement unit 14, and if the output voltage is directly input to the parametric measurement unit 14, damage may occur.

  For example, assume that the output voltage of the external amplifier 30 is 10 V, the power supply voltage Vcc of the parametric measurement unit 14 is 8 V, the gain of the external amplifier 30 is doubled, and no current flows through the current sense resistor R1. At this time, if the additional circuit 20 does not exist, the output voltage 10V of the external amplifier 30 is directly input to the parametric measurement unit 14 and exceeds the power supply voltage 8V, so that the parametric measurement unit 14 may be destroyed. is there. Therefore, as described above, the gain of the voltage sense amplifier 34 is set to 1/2, the output voltage is set to 5V, and the power supply voltage is lowered from 8V to prevent the parametric measurement unit 14 from being destroyed.

  As described above, according to the first embodiment of the present invention having the additional circuits 16, 18, and 20, the parametric measurement unit 14 that can amplify not only the current of the input signal but also the output range and measurement range of the voltage can be amplified. The DC module device 10 that expands the measurement / output range is obtained.

  FIG. 3 is a circuit diagram illustrating an apparatus in which an external circuit is added to the parametric measurement unit as a comparative example for the first and second embodiments of the present invention shown in FIG. 1 and FIG. 2 described later. The additional circuit 42 included in the device 40 includes an external amplifier 44 that can only amplify current. However, even if the external amplifier 44 is replaced with one similar to the external amplifier 30 shown in FIG. 1 that can also amplify the voltage, the device 40 shown in FIG. Therefore, the parametric measurement unit 14 is directly input with the voltage which is applied to both ends of the current sense resistor R1 and whose absolute value of the potential is increased. Such a potential having a high absolute value exceeds the power supply voltage of the parametric measurement unit 14 and causes the destruction of the parametric measurement unit 14. Therefore, with the configuration shown in FIG. 3, the voltage of the input signal cannot be amplified.

(Second embodiment of the present invention)
FIG. 2 is a circuit diagram showing a second embodiment of the DC module device according to the present invention. In the following, only the points different from FIG. 1 will be described with reference to FIG. The DC module device 50 that expands the measurement / output range of the parametric measurement unit 14 shown in FIG. 2 is obtained by adding an additional circuit 52 to the configuration of FIG. The additional circuit 52 includes an additional current sense resistor R3 connected in parallel to the current sense resistor R1, a switch SW7 for switching on / off the output of the resistor R3 to the device under test 12, and a current sense resistor R1 or additional A third switch SW8 for applying a potential difference between both ends of the current sense resistor R3 to the external differential amplifier 32 is included.

  In FIG. 1, when the voltage range is expanded, that is, when a signal output from the external amplifier 30 is given to the device under test 12, a single current range is provided. However, as shown in FIG. By adding the additional current sense resistor R3, it is possible to provide a plurality of current ranges while expanding the voltage range. Therefore, when a high voltage is applied, it is possible to apply and measure a current having a wide dynamic range.

  The current sense resistor R1 originally provided and the newly provided additional current sense resistor R3 may be designed, for example, so that the applied voltages are equal. For example, it is assumed that a current of 1 mA flows through the current sense resistor R1, and a current of 10 mA flows through the additional current sense resistor R3. At this time, if a voltage of 1V is generated in the current sense resistor R1, the values of the resistors R1 and R3 are set so that a voltage of 1V is also generated in the additional current sense resistor R3. That is, R3 = R1 / 10 (the resistance value is also indicated by a reference sign).

  When the current sense resistor R1 is used, the switch SW7 is turned on, the switch SW8 is a right terminal, and the switch SW5 is turned off to secure a dynamic range of 1 mA current. On the other hand, when the additional current sense resistor R3 is used, the switch SW7 is off, the switch SW8 is the left terminal, and the switch SW5 is on, and a dynamic range of 10 mA current is secured. As described above, the current sense resistor R1 and the additional current sense resistor R3 are exclusively selected, and an input signal having an amplified voltage flows through any of the exclusively selected current sense resistor R1.

The dynamic range of 10 mA when the additional current sense resistor R3 is used includes the dynamic range of 1 mA when the current sense resistor R1 is used, and is therefore suitable for outputting and measuring a relatively large current. However, the resolution is coarser at 10 mA than at the dynamic range of 1 mA. Usually, since an input signal is given from a D / A (Digital-Analogue) converter, if a 16-bit D / A converter is used, a resolution of (1 mA / 2 ¹⁶ ) can be obtained when the dynamic range is 1 mA. . However, when the dynamic range is 10 mA, the resolution becomes (10 mA / 2 ¹⁶ ), and the resolution becomes coarse. In such a case, it is better to use a current sense resistor R1 having a dynamic range of 1 mA. Thus, according to this embodiment, the dynamic range can be switched according to the current range of the input signal, in other words, the resolution can be switched.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention is applicable to a DC module device that expands the measurement / output range of a parametric measurement unit in an IC tester.

1 is a circuit diagram showing a first embodiment of a DC module device according to the present invention. It is a circuit diagram which shows 2nd Embodiment of the DC module apparatus by this invention. FIG. 3 is a circuit diagram showing a DC module device as a comparative example with respect to the embodiment shown in FIGS. 1 and 2.

Explanation of symbols

10, 50 DC module device 12 Device under test 14 Parametric measurement unit 16, 18, 20, 52 Additional circuit 22 Internal amplifier 24 Internal resistance 26 Internal differential amplifier 30 External amplifier 32 External differential amplifier R1 Current sense resistor R3 Additional current sense resistance

Claims (3)

An internal resistor through which an input signal to the device under test flows, an internal differential amplifier capable of detecting the current value from the potential difference between both ends of the internal resistor, and a voltage receiving unit for receiving the voltage of the output signal coming from the device under test In a DC module device that expands the measurement / output range of a parametric measurement unit comprising:
An external amplifier for amplifying the voltage of the input signal;
A current sense resistor through which the amplified input signal flows;
An external differential amplifier for converting a potential difference between both ends of the current sense resistor into a ground-reference potential difference;
When the input signal flowing through the internal resistance is input to the device under test, the amplified input signal flowing through the current sense resistor is selected by selecting a potential difference between both ends of the internal resistance to the internal differential amplifier. Is input to the device under test, a first switch that selects and supplies the ground-reference potential difference to the internal differential amplifier;
A voltage sense amplifier that amplifies the voltage of the output signal from the device under test and gives the voltage to the voltage receiver;
The gain of the voltage sense amplifier is set to 1 when the first switch selects the potential difference across the internal resistor, and the gain of the voltage sense amplifier when the first switch selects the ground-reference potential difference. And a second switch having (1 / the gain of the external amplifier) as a direct current module device. The DC module device for expanding a measurement / output range of a parametric measurement unit according to claim 1 , wherein the external amplifier also amplifies the current of the input signal. An additional current sense resistor connected in parallel to the current sense resistor and selected exclusively by the current sense resistor and through which the amplified input signal flows;
2. The method according to claim 1 , further comprising: a third switch that applies a potential difference between either one of the exclusively selected current sensing resistor or the additional current sensing resistor to the external differential amplifier. Or the DC module device according to 2;

Images