JP2008205685A - Optical mosfet relay driving circuit and semiconductor testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the performance of a device is deteriorated due to a wait time when drive is performed by setting the wait time in order to absorb nonuniformity since nonuniformity exists in an on/off time and the on/off time is changed due to the secular change of a light receiving element, etc., though many optical MOSFET relays are used in the semiconductor testing device. <P>SOLUTION: The optical MOSFET relays are driven by a variable current driving part capable of varying an output current. Then the output current of the variable current driving part is adjusted, thereby obtaining a value with the on/off time set therein. Thus, there is no need to set the wait time since the nonuniformity of the on/off time of the optical MOSFET relay can be absorbed, thereby improving the performance of the semiconductor testing device. Besides, the secular change of the on/off time is compensated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical MOSFET relay driving circuit capable of suppressing variations in on / off time and a semiconductor test apparatus using the optical MOSFET relay driving circuit.

  FIG. 4 shows the configuration of the pin electronics of the semiconductor test apparatus. The pin electronics is a part having a function of applying a desired test signal to the device under test and measuring the voltage, current, timing, etc. of the output signal of the input device under test.

  In FIG. 4, reference numeral 10 denotes pin electronics, which includes a circuit including a driver 11, a comparison unit 12, a function relay 13, a DC sense relay 14, a DC force relay 15, and an output relay 16. Some of these relays may be omitted. A plurality of these circuits are built in corresponding to the measurement target pins of the device under test 18.

  The power supply VIH, VIL and the test signal are input to the driver 11, and the output level becomes VIH or VIL depending on the test signal. The output of the driver 11 is applied to the device under measurement 18 via the function relay 13 and the output relay 16.

  The comparison unit 12 is composed of two comparators having a variable reference voltage, and measures the output signal level of the driver 11. A DC power is supplied to a device under measurement 18 from a PMU (Pin Measurement Unit) 17 (which may be a DC module) via a DC force relay 15, and an output of the device under measurement 18 via a DC sense relay 14. Capture the signal and measure its voltage, timing, etc.

  In the pin electronics 10, relays such as a function relay 13, a DC sense relay 14, a DC force relay 15, and an output relay 16 are used to establish a signal path, and these relays are switched according to the test contents. .

  Conventionally, as these relays, reed relays (mechanical relays) that turn on and off the encapsulated contacts by passing a current through a coil wound around the glass tube enclosing the contacts and inert gas are used. However, there were problems such as short mechanical contact life. For this reason, semiconductor relays have recently been used. Among semiconductor relays, optical MOSFET relays using optical MOSFETs are widely used because they have bidirectional conductive characteristics and can be used for intermittent AC signals and have low on-resistance. .

  FIG. 5 shows the internal configuration of the optical MOSFET relay. In FIG. 5, reference numeral 20 denotes an optical MOSFET relay, which includes an LED 21, a photoelectric element / control circuit 22, and a MOSFET 23. The LED 21 emits light when a current exceeding a certain value flows, and does not emit light when the current is less than that. This light is detected by a solar cell in the photoelectric element / control circuit 22. The photoelectric element / control circuit 22 controls the gate voltage of the MOSFET 23, turns on the MOSFET 23 when detecting light from the LED 21, and turns it off when not detecting it. For this reason, an output contact can be turned on / off by controlling the electric current sent through LED21.

  FIG. 6 shows an example of an optical MOSFET relay drive circuit. The same elements as those in FIG. 5 are denoted by the same reference numerals and description thereof is omitted. In the drive circuit 1 of FIG. 5A, the anode of the LED in the optical MOSFET relay 20 is connected to the power supply Vcc, and the cathode is connected to the output terminal of the driver 31 composed of a low saturation transistor. When the output of the controller 30 becomes high level, the transistor in the driver 31 becomes conductive and the optical MOSFET relay 20 is turned on. The controller 32 in FIG. 5B is configured by a custom IC, and the LED of the optical MOSFET relay 20 is controlled by the FET in the controller 32. Since the operation is the same as (A), the description is omitted.

  Patent Document 1 describes an invention of a photocoupler-type switch element driving circuit capable of high-speed operation and capable of suppressing heat generation by suppressing power consumption. The present invention will be described with reference to FIG. In FIG. 7, reference numeral 40 denotes a timing control circuit, which includes counters 41 and 43 and AND gates 42 and 44. The output of the counter 41 is input to the AND gate 42, and the output of the counter 43 is input to the AND gate 44. The outputs of the signal source 48 are input to the counters 41 and 43 and the AND gates 42 and 44, and the clock is input to the counters 41 and 43. Different setting values are set in the counters 41 and 43.

  Reference numerals 45 to 47 denote FETs, which are driven by the output of the signal source 48 and the outputs of the AND gates 42 and 43, respectively. The FETs 45 to 47 are connected in parallel to drive the photocoupler type switch element 49.

  In such a configuration, when the switch element 49 is turned on, the FETs 45 to 47 are simultaneously turned on by the output of the signal source 48. Since the LED in the switch element 49 is driven with a large current, it is turned on at high speed. The counters 41 and 43 start counting.

  When the count value of the counter 41 reaches the set value, the output of the AND gate 42 changes and the FET 46 is turned off. For this reason, the drive current of the switch element 49 decreases. Subsequently, the count value of the counter 43 reaches the set value, and the FET 47 is also turned off. The drive current of the switch element 49 further decreases.

  In this way, the switch element is turned on with a large current, and when it is turned on, the drive current is reduced to maintain the on state. Therefore, the switch element 49 can be turned on at high speed and the power consumption can be reduced.

  The on-time and off-time of the optical MOSFET relay vary depending on the magnitude of drive current, lot variation, operating environment temperature, aging of the element, and the like. For example, the amount of light emission decreases due to aging of the built-in LED, and the detection capability decreases due to deterioration of the storage performance of the solar cell. Therefore, the on-time tends to become longer due to secular change.

  This will be described with reference to FIG. FIG. 8A is a test circuit, and FIG. 8B is a characteristic diagram schematically showing a test result. In FIG. 8A, the optical MOSFET relay 20 is driven by a controller 32. This drive current is assumed to be Iin. One end of the output contact of the optical MOSFET relay 20 is connected to the power supply Vcc, and the other end is connected to a common potential point via a resistor. The voltage across the resistor (output voltage) is Vout.

  The upper part of FIG. 8B is a characteristic diagram showing changes in the drive current Iin. The drive current Iin increases at a constant inclination angle to reach a constant value, and after a predetermined time elapses, decreases at a constant inclination angle and becomes zero.

  The lower part of (B) is a characteristic diagram showing changes in the output voltage Vout. Due to the delay of the optical MOSFET relay 20, Vout increases later than the drive current Iin. The time t1 from when the drive current Iin starts to increase until the output voltage Vout reaches ½ of the final value is referred to as ON time. As described above, the on-time varies depending on various factors and has a variation of Δt1. The time t2 from when the drive current Iin starts to decrease until the output voltage Vout becomes ½ is referred to as the off time. This off time also changes due to various factors and has a variation of Δt2.

  In a semiconductor test apparatus using a large number of optical MOSFET relays, if the on time and the off time vary, the establishment of the path becomes unstable and various failures occur. Therefore, an on time weight tsw longer than t1 + Δt1 and an off time weight tew longer than t2 + Δt2 are set to absorb variations in on time and off time.

  FIG. 9 shows an example of a driver circuit that can shorten the on-time. In addition, the same code | symbol is attached | subjected to the same element as FIG. 6, and description is abbreviate | omitted. In this drive circuit, a resistor inserted between the driver 31 and the optical MOSFET relay 20 is divided into resistors 50 and 51, and a capacitor 52 is arranged in parallel with the resistor 50. As can be seen from FIG. 8, when the optical MOSFET relay 20 is turned on, the drive current changes abruptly, so that the impedance of the capacitor 52 decreases. Therefore, a large drive current can be supplied to the optical MOSFET relay 20 at the time of turning on, and the on time can be shortened.

  However, failure may occur if the on time is too short. This example will be described with reference to FIG. FIG. 10A is a test circuit, and FIG. 10B is a characteristic diagram schematically showing a test result. In addition, the same code | symbol is attached | subjected to the same element as FIG. 8, and description is abbreviate | omitted. In this test, the optical MOSFET relay 20 is turned off, a test signal is applied to the contact from the test signal applying device 53, and the optical MOSFET relay 20 is turned on immediately after the test signal is set to zero.

  In the upper part of FIG. 9B, 54 is a curve representing a change in the output voltage of the test signal applying device 53. Due to settling time, this output voltage does not immediately go to zero, but becomes a trailing curve. A curve 55 represents the opening degree of the optical MOSFET relay 20. The opening gradually increases due to the on-time. Further, the curve 55 becomes a plurality of curves due to variations in the on-time.

If the contact of the optical MOSFET relay 20 starts to turn on before the output voltage of the test signal applying device 53 becomes 0, this output voltage appears at the contact of the optical MOSFET relay 20 and a spike is generated. The lower 56 represents this spike. As can be seen from the figure, this spike becomes larger as the on-time of the optical MOSFET relay 20 is shorter.
Japanese Patent No. 3615036

  However, such an optical MOSFET relay drive circuit has the following problems. As described with reference to FIG. 8, the on-time weight tsw and the off-time weight tw are set to drive the optical MOSFET relay in consideration of the element variation, the influence of the surrounding environment, and the secular change. However, there is a problem that the time for testing the device under test increases and the performance of the apparatus decreases. On the other hand, if the wait time is short, variations in elements and changes over time cannot be sufficiently absorbed, and there is a problem that the performance of the apparatus is deteriorated.

  Further, when the drive current is increased and a capacitor is inserted in parallel with the resistor as shown in FIG. 9, the on-time is shortened, but there is a problem that the life of the optical MOSFET relay is shortened. Furthermore, as shown in FIG. 10, when the on-time is too short, a spike is generated and the performance of the apparatus is degraded.

  Accordingly, an object of the present invention is to provide an optical MOSFET relay drive circuit capable of reducing variations in on-time and off-time by measuring the on-time and off-time of the optical MOSFET relay and controlling the drive current according to the measurement result. Another object of the present invention is to provide a semiconductor test apparatus using the drive circuit.

In order to solve such a problem, the invention according to claim 1 of the present invention,
A voltage generator for applying a voltage to the optical MOSFET relay;
A comparator for comparing the output voltage of the optical MOSFET relay with a predetermined value;
Timing signal generation for measuring the on-time and / or off-time of the optical MOSFET relay by outputting a strobe signal for defining comparison timing to the comparison unit and referring to the output of the comparison unit while shifting the strobe signal And
A variable current driving unit that outputs a driving current to the optical MOSFET relay and adjusts the driving current based on an on time and / or an off time measured by the timing signal generation unit;
Is provided. Variations in on-time and off-time can be reduced.

The invention according to claim 2 is the invention according to claim 1,
The timing signal generator controls the drive current output from the variable current driver so that the on-time and / or off-time of the optical MOSFET relay becomes a set value. The optimum drive current can be set automatically.

The invention according to claim 3 is the invention according to claim 1 or claim 2,
The variable current driving unit includes a driver that outputs a driving current to the optical MOSFET relay, a resistor that is disposed in a path through which the driving current flows, and a capacitor that is connected in parallel to the resistor. The drive current can be varied by changing the resistance value and / or the capacitance value of the capacitor. The drive current can be varied with a simple configuration.

The invention according to claim 4 is the invention according to claim 1 or claim 2,
The variable current drive unit includes a DA converter that converts a digital value into an analog signal, and changes the drive current of the optical MOSFET relay by changing the digital value input to the DA converter. . The drive current can be varied accurately and over a wide range.

The invention according to claim 5 is the invention according to claim 1 or 2,
The variable current drive unit includes a plurality of switching elements connected in parallel, and the output current can be varied by varying the number of switching elements that are turned on among these switching elements. Suitable for LSI.

The invention according to claim 6 is the invention according to claim 1 or 2,
The variable current drive unit includes a plurality of constant current elements connected in parallel, and a constant current element drive unit that selectively supplies current to the constant current elements, and changes the number of the constant current elements that supply current. Thus, the output current is made variable. It is suitable for LSI implementation and the configuration can be simplified.

The invention according to claim 7 is the invention according to claim 1 or 2,
The variable current drive unit is composed of a current variable amplifier, and the output current is varied by changing the current output from the current variable amplifier. The configuration can be simplified.

The invention described in claim 8
A plurality of optical MOSFET relays are provided, and signals are output to the semiconductor under measurement by controlling on / off of these optical MOSFET relays, and the semiconductor under test is inspected by inputting signals from the semiconductor under measurement. In semiconductor test equipment,
The optical MOSFET relay drive circuit according to any one of claims 1 to 7 is used to drive the plurality of optical MOSFET relays. The wait time can be shortened and the performance of the test apparatus can be improved.

The invention according to claim 9 is the invention according to claim 8,
The voltage generation unit and the comparison unit use elements used for semiconductor inspection. Additional parts can be reduced.

As is apparent from the above description, the present invention has the following effects.
According to the first, second, third, fourth, fifth, sixth, seventh, eighth and ninth inventions, the on-time and off-time of the optical MOSFET relay are measured, and the on-time and off-time become set values. Thus, the drive current of the optical MOSFET relay was adjusted. This optical MOSFET relay drive circuit was used in a semiconductor test apparatus.

  Since variations in on-time and off-time can be reduced, the wait time set to absorb variations in on-time and off-time can be shortened when used in a device using a large number of optical MOSFET relays such as a semiconductor test device. It is possible to improve the performance of the apparatus.

  Further, the on-time and off-time of the optical MOSFET relay tend to become longer due to secular change or the like. However, when the optical MOSFET relay driving circuit of the present invention is used, the on-time and off-time can be kept stable. .

  Furthermore, by using a voltage source or a comparator used for a device test in a semiconductor test apparatus as a component for measuring an on time and an off time, an additional component can be reduced.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an optical MOSFET relay drive circuit according to the present invention. In FIG. 1, 60 is an optical MOSFET relay to be controlled. A voltage generator 61 generates a voltage that is turned on / off by the optical MOSFET relay 60. The output voltage of the voltage generator 61 is applied to one of the contacts of the optical MOSFET relay 60.

  A comparison unit 62 receives the other contact voltage of the optical MOSFET relay 60, that is, the output of the optical MOSFET relay 60, and compares the level with a reference voltage. The comparison unit 62 has, for example, a configuration like the comparison unit 12 of FIG. 4 and detects whether or not the output voltage of the optical MOSFET relay 60 is within a certain range.

  Reference numeral 63 denotes a timing signal generator, which receives the output of the comparator 62 and outputs a strobe signal to the comparator 62. This strobe signal gives the timing at which the comparator 62 compares the output voltage of the optical MOSFET relay 60.

  Reference numeral 64 denotes a variable current drive unit, which receives a drive signal and a current control signal from the timing signal generator 63 and outputs a drive current to the optical MOSFET relay 60. The variable current drive unit 64 supplies a drive current to the optical MOSFET relay 60 at the timing of the drive signal and stops the supply. Further, the value of this drive current is changed by a current control signal. Note that “changing the value of the drive current” includes not only changing the direct current value but also changing the peak current value at the start or stop of the supply.

  Next, the operation of this embodiment will be described. The timing signal generator 63 controls the drive signal to turn on / off the optical MOSFET relay 60 and measures the on time and the off time. The on-time and off-time are measured by turning on / off the optical MOSFET relay 60 while gradually shifting the timing of comparison by the comparator 62 using the strobe signal, and the output voltage of the optical MOSFET relay 60 is set to a desired voltage level (for example, voltage generation). This is performed by obtaining the time until the output voltage becomes ½ of the output voltage of the unit 61.

  The timing signal generator 63 changes the output current of the variable current driver 64 by the current control signal so that the on time and the off time of the optical MOSFET relay 60 are set. When an appropriate output current is found, the optical MOSFET relay 60 is subsequently driven with this output current. By doing in this way, the ON time and OFF time of several optical MOSFET relay can be united.

  If a set value that gives an appropriate output current is stored and the variable current drive unit 64 is controlled with this set value when the power is turned on, the time for measuring the on-time and the off-time each time is obtained. Can be omitted. As described above, the on-time and the off-time change with time. Therefore, it is only necessary to set the on-time and off-time periodically to update the set value for giving an appropriate current. In this embodiment, the timing signal generator 63 outputs a current control signal to the variable current driver 64 to set the drive current. However, based on the ON time and OFF time measured by the timing signal generator 63. Thus, the drive current may be adjusted manually.

  Further, the drive current may be determined so that either the on time or the off time becomes a set value. Since the on-time and the off-time are related, even if only one of them is matched, the variation of both the on-time and off-time can be reduced. In this way, the adjustment time can be shortened.

  As described with reference to FIG. 4, a plurality of optical MOSFET relays are used in pin electronics, and a driver for supplying a voltage to these optical MOSFET relays and a comparator for measuring the output voltage level of the optical MOSFET relay are arranged in advance. Yes. By using the driver and the comparison unit as the voltage generation unit 61 and the comparison unit 62, the additional portion can be reduced.

  FIG. 2 is a block diagram of the pin electronics of the semiconductor test apparatus according to the present invention. The same elements as those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. Further, in actual pin electronics, a plurality of sets of circuits composed of the driver 11, the comparator 12, and the optical MOSFET relays 13 to 16 are arranged so as to correspond to a plurality of pins, but in order to avoid complexity, In this embodiment, only one set is described.

  In FIG. 2, a formatter 70 outputs a predetermined test signal DRD. This signal DRD is input to the driver 11. Reference numeral 71 denotes a digital comparator which receives the outputs HCMP and LCMP of the comparator 12 and determines whether or not the input signal of the comparator 12 is within a predetermined level range. The comparator 12 and the digital comparator 71 constitute the comparator 62 shown in FIG.

  Reference numeral 72 denotes a timing signal generator, which corresponds to the timing signal generator 63 of FIG. The timing signal generator 72 receives the comparison result from the digital comparator 71 or outputs the strobe signal STROBE to the comparator 12 and the format signal FMT to the formatter 70.

  Reference numeral 73 denotes a variable current drive unit, which corresponds to the variable current drive unit 64 of FIG. The variable current driver 73 receives a drive signal and a current control signal from the timing signal generator 72 and outputs a drive current to the optical MOSFET relays 13 to 16. The value of this drive current can be varied by a current control signal. The optical MOSFET relays 13 to 16 are controlled to be turned on and off by drive currents FCON, DSON, DFON, and OUTON, respectively.

  In such a configuration, when the on-time and off-time of the optical MOSFET relay 13 are adjusted, the optical MOSFET relays 14 and 16 are turned off in advance, and a constant voltage is applied from the PMU 17 to turn on the optical MOSFET relay 15. At this time, the output of the driver 11 is turned off.

  The timing signal generator 72 outputs the drive signal by repeating the operation of turning on and off the optical MOSFET relay 13 while shifting the strobe signal STROBE, and after stopping the output, the output voltage of the optical MOSFET relay 13 (comparator 12). For the input voltage) to a desired voltage level (for example, ½ of the constant voltage applied from the PMU 17). This time becomes on time and off time. The current value of the drive current FCON is changed by the current control signal to obtain the drive current value at which the on time and the off time are set values, and the optical MOSFET relay 13 is driven by this current value.

  When adjusting the on-time and off-time of the optical MOSFET relay 14, the optical MOSFET relay 13 is turned on, and 15 and 16 are turned off, and a constant voltage is applied from the PMU 17 to the optical MOSFET relay 14. Since the method for adjusting the on time and the off time is the same as that in the case of the optical MOSFET relay 13, the description thereof is omitted.

  When adjusting the on-time and off-time of the optical MOSFET relay 15, the optical MOSFET relay 13 is turned on and the 14 and 16 are turned off, and a constant voltage is applied from the PMU 17 to the optical MOSFET relay 15. Since the method for adjusting the on time and the off time is the same as that in the case of the optical MOSFET relay 13, the description thereof is omitted.

  Since nothing is connected to one of the output contacts of the optical MOSFET relay 16, the on-time and off-time cannot be measured by the same technique as the optical MOSFET relays 13-15. Therefore, a board used for diagnosis / calibration is attached instead of the device under test 18 shown in FIG. 4, and a comparison circuit corresponding to the comparison unit 12 and the digital comparison unit 71 is mounted on this board. The comparison timing of the comparison circuit can be controlled by the strobe signal STROBE output from the timing signal generator 72, and the output is input to the timing signal generator 72.

  The optical MOSFET relays 13 and 14 are turned off and the optical MOSFET relay 15 is turned on with the substrate on which the comparison circuit is mounted, and a constant voltage is applied from the PMU 17 to the optical MOSFET relay 16. Since the method for measuring and adjusting the on time and the off time is the same as that of the optical MOSFET relay 13, the description thereof is omitted. The constant voltage may be applied from the driver 11 to the optical MOSFET relay 16 with the optical MOSFET relay 13 turned on and the switches 14 and 15 turned off.

  Further, a constant voltage source is mounted on a diagnostic / calibration board to be mounted instead of the device under test 18, the optical MOSFET relay 13 is turned on, the 14 and 15 are turned off, and the comparison unit 12 and the digital comparison unit 71 are turned on. The off time may be measured.

  1 and FIG. 2, the output currents of the variable current driving units 64 and 73 are varied by the current control signal output from the timing signal generating units 63 and 72. However, the timing signal generating units 63 and 72 The on-time and off-time measured may be displayed, and the output current may be manually varied. Alternatively, the current setting value set in the variable current driving unit 73 may be stored, and the stored value may be read and set when the power is turned on.

  FIG. 3 shows an example of an embodiment of the variable current driving units 64 and 73. Reference numeral 20 denotes an optical MOSFET relay. FIG. 3A shows an embodiment using a variable resistor whose resistance value can be varied and a variable capacitor whose capacity can be varied. In FIG. 3A, 80 is a variable resistor, and 81 is a variable capacitor. The variable resistor 80 and the variable capacitor 81 are connected in parallel, and this parallel circuit is inserted in the middle of the path between the driver 31 and the optical MOSFET relay 20.

  In such a configuration, when the resistance value of the variable resistor 80 is reduced, the driving current of the optical MOSFET relay is increased, and the on time and the off time can be shortened. Similarly, when the resistance value is increased, the drive current is reduced and the on time and off time are lengthened. Further, when the capacitance of the variable capacitor 81 is changed, the magnitude of the peak current generated at the rise and fall of the drive current can be changed, and the on time and the off time can be shortened. Note that both the variable resistor 80 and the variable capacitor 81 may be adjusted, or only one of them may be adjusted.

  FIG. 3B shows an embodiment in which the drive voltage is changed using a DA converter. In FIG. 3B, 82 is a memory, 83 is a read control unit, and 84 is a DA converter. The read control unit 83 reads the set value stored in the memory 82 and sets it in the DA converter 84. By changing this set value, the output voltage of the DA converter changes, and the drive current of the optical MOSFET relay 20 can be varied.

  FIG. 3C shows an example of a variable current driving unit using a constant current element that supplies a constant current. In FIG. 3C, reference numeral 86 denotes a constant current element, which is connected in parallel to supply a driving current to the optical MOSFET relay 20. Reference numeral 85 denotes a constant current element driving unit that drives the selected constant current element 86. The drive current of the optical MOSFET relay 20 can be changed by changing the number of constant current elements to be driven.

  In addition to these embodiments, a driving current of the optical MOSFET relay can be changed by connecting a plurality of FETs in parallel as in the driving circuit shown in FIG. 7 and changing the number of FETs to be turned on. . In this embodiment, the peak current at the on and off times can be changed by shifting the time during which the FET is turned on. A transistor can be used instead of the FET. In addition, a variable current amplifier that can vary the value of the output current may be used as the variable current driver.

It is a block diagram which shows one Example of this invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows the Example of a variable current drive part. It is a block diagram of pin electronics. It is a structural diagram of an optical MOSFET relay. It is a block diagram of an optical MOSFET relay drive circuit. It is a block diagram of a photocoupler type switch element drive circuit. It is a characteristic view of an optical MOSFET relay. It is a block diagram of an optical MOSFET relay drive circuit. It is a characteristic view for demonstrating that a spike generate | occur | produces.

Explanation of symbols

11 Driver 12 Comparison unit 13-16, 20, 60 Optical MOSFET relay 17 PMU
61 Voltage generator 62 Comparator 63, 72 Timing signal generator 64, 73 Variable current driver 71 Digital comparator 80 Variable resistor 81 Variable capacitor 82 Memory 83 Read controller 84 DA converter 85 Constant current element driver 86 Constant current element

Claims (9)

A voltage generator for applying a voltage to the optical MOSFET relay;
A comparator for comparing the output voltage of the optical MOSFET relay with a predetermined value;
Timing signal generation for measuring the on-time and / or off-time of the optical MOSFET relay by outputting a strobe signal for defining comparison timing to the comparison unit and referring to the output of the comparison unit while shifting the strobe signal And
A variable current driving unit that outputs a driving current to the optical MOSFET relay and adjusts the driving current based on an on time and / or an off time measured by the timing signal generation unit;
An optical MOSFET relay drive circuit comprising:   The timing signal generator is configured to control a drive current output from the variable current driver so that an ON time and / or an OFF time of the optical MOSFET relay becomes a set value. 2. An optical MOSFET relay drive circuit according to 1.   The variable current driving unit includes a driver that outputs a driving current to the optical MOSFET relay, a resistor that is disposed in a path through which the driving current flows, and a capacitor that is connected in parallel to the resistor. 3. The optical MOSFET relay drive circuit according to claim 1, wherein the drive current is varied by changing a resistance value of the capacitor and / or a capacitance value of the capacitor.   The variable current drive unit includes a DA converter that converts a digital value into an analog signal, and the drive current of the optical MOSFET relay is varied by varying the digital value input to the DA converter. The optical MOSFET relay drive circuit according to claim 1 or 2.   The variable current drive unit includes a plurality of switching elements connected in parallel, and the output current is varied by varying the number of switching elements that are turned on among these switching elements. The optical MOSFET relay drive circuit according to claim 1 or 2.   The variable current drive unit includes a plurality of constant current elements connected in parallel, and a constant current element drive unit that selectively supplies current to the constant current elements, and changes the number of the constant current elements that supply current. 3. The optical MOSFET relay drive circuit according to claim 1, wherein the output current is made variable by the above.   3. The light according to claim 1, wherein the variable current driving unit is constituted by a variable current amplifier, and the output current is varied by changing a current output from the variable current amplifier. MOSFET relay drive circuit. A plurality of optical MOSFET relays are provided, a signal is output to the semiconductor under measurement by controlling on / off of these optical MOSFET relays, and the semiconductor under test is tested by inputting a signal from the semiconductor under measurement. In semiconductor test equipment,
8. A semiconductor test apparatus using the optical MOSFET relay drive circuit according to claim 1 to drive the plurality of optical MOSFET relays.   9. The semiconductor test apparatus according to claim 8, wherein the voltage generator and the comparator use elements used for semiconductor inspection.

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