JPS62116273A - Electronic device driving circuit - Google Patents

Abstract

PURPOSE:To perform the connection and separation of a terminal power source, by providing an electronic switch operable at a high speed and a driver circuit. CONSTITUTION:At the time of an output mode, for example, when PH and PH* signals being complementary signals are simultaneously turned ON, bipolar transistors 18, 22 simultaneously come to an ON-state and each diode of a diode bridge (DB)14 is biased to a positive direction by bias devices 24, 26 and a power source applying terminal T2 is connected to an output terminal T3 through DB 14. FET31B is turned ON by an I/O signal and, because a driving power source 28 is connected to a terminal T2 by a connector 31, the voltage corresponding to the output voltage of said terminal T2 appears at a terminal T3 and applied to an electronic device pin connected by a connector 36. Next, at the time of an input mode, PH and PH* signals are turned ON and the terminal T2 is connected to the terminal T3 through DB 14. FET31A is turned ON by the I/O signal and a terminal power source 30 is connected to the terminal T3 and the voltage corresponding to the output voltage of the power source 30 is outputted to the terminal T3 and the pin of an electronic device is terminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a drive circuit for an electronic device having pins that require termination.

[Prior Art] As a conventional example of such an electronic device drive circuit, an IC
An electronic device drive circuit used in an electronic device inspection system such as the following will be explained with reference to FIG.

In this figure, 100 is a three-state driver, to which drive control L=i% is input, and
DC voltages VIH and VIL are applied. The output of this driver 100 is connected via a signal transmission path 104 to a pin connection terminal 10B to which a pin of an electronic device to be tested is connected. A resistor 102 (for example, 50Ω) is inserted to match the output impedance of the driver 100 and the characteristic impedance of the signal transmission line 104.

In the output mode (pin drive mode), the driver lOO becomes active and outputs the - - DC voltage VIH or VIL specified by the drive control signal as a drive voltage, which is applied to the pin connection terminal 106. In input mode, driver 100 is in a high impedance state. In this input mode, signals output to pins of the electronic device are checked by a comparator (not shown) or the like.

Now, some electronic devices require pin termination (eg, ECL devices, MOS devices). When it is necessary to drive an electronic device that requires such a termination, conventionally a pin connection terminal 106 is used as shown in FIG.
A terminating resistor 110 (for example, 50Ω) and a terminating power source 112 are connected via a reed relay 108.

Note that the electric device drive circuit shown in the figure is generally provided in a part that directly interfaces with an electronic device, that is, a test head.
There are many types that correspond to the pins of electronic devices.

[Problems to be Solved] Now, the reed relay 108 is set to the closed or open state regardless of the mode. Even with this configuration, E
There are no particular problems with the output pins of CL devices, etc.

However, for input/output pins that require termination such as ECL devices, if the reed relay 108 is always closed,
In the output mode (drive mode), the voltage applied to the output pin (drive voltage) is affected by the connection of the terminating power supply and terminating resistor. For this reason, conventionally, ECL
There was a problem in that 11 degrees of inspection had to be carried out without terminating the input/output pins of devices, etc.

In order to solve this problem, it is conceivable to open and close the reed relay 108 depending on the mode.

However, the response speed of reed relays is generally quite slow compared to the operating speed of high speed electronic devices such as ECL devices. On the other hand, in testing high-speed electronic devices such as ECL devices, it is necessary to switch modes at high speed.

Therefore, when handling ECL devices, etc., it is impossible to open and close the reed relay 108 in accordance with the input/output mode switching, and the reed relay 108 must be always closed or open. The problem cannot be resolved.

Another problem is that because the termination circuit is connected in parallel to the pin connection terminal 106, the capacitance seen from the pin connection terminal 106 increases, resulting in large distortions of the pin drive voltage waveform and pin output voltage waveform. There was a problem.

[Purpose of the Invention] Accordingly, an object of the present invention is to be able to properly terminate input/output pins of high-speed ECL devices without interfering with their driving, and to reduce noise from the viewpoint of pin connection terminals. An object of the present invention is to provide an electric device drive circuit which aims to reduce the electric field 11t.

[Y stage for solving the problem] In order to achieve this objective 1-1, according to the present invention, the electronic device drive circuit connects the first and second voltage application terminals, and operates in the output mode. A driver that outputs a voltage corresponding to the voltage applied to the first or second voltage application terminal, and also outputs a voltage corresponding to the voltage applied to the second voltage application terminal in the input mode, and the first voltage application terminal. the first connected to
interposed between the driving power source, the second driving power source, the terminating power source, and the second voltage application terminal, and connects the second driving power source to the second voltage application terminal in the output mode. , an electronic switch that connects the termination power supply to the second voltage application terminal in the input mode, and an impedance matching and termination terminal inserted between the output terminal of the driver and the pin connection terminal to which the pin of the electronic device is connected. The configuration includes a resistor.

[In the output mode, the drive voltage corresponding to the voltage applied to the voltage application terminal by the drive power supply is supplied to the pin connection terminal, and the termination power supply is disconnected, so the electronic device can perform driving operations that are not affected by the termination power supply. can be applied to the pin.

In the input mode, the termination power supply is essentially connected to the output of the driver so that the pins of the electronic device can be terminated.

Connection and disconnection of the terminating power supply is done by an electronic switch and the driver's internal circuit, but the electronic switch can easily be made at a sufficiently high speed, and the driver's internal circuit itself is inherently capable of sufficiently high-speed operation. Because it is,
It is possible to connect and disconnect the terminal power supply at high speed.

Therefore, according to the present invention, the human output pin of a high-speed electronic device such as an ECL device can be terminated in the input mode without interfering with pin driving in the output mode.

In addition, since the termination circuit consisting of the termination power supply, termination resistor, reed relay, etc. is not connected in parallel to the pin connection terminal, the electrostatic field I11 seen from the pin connection terminal is smaller than before, and the pin drive voltage Waveform and pin output
No waveform attempts are reduced.

[Embodiment] Hereinafter, referring to the drawings, an embodiment of the present invention will be described.

FIG. 1 is a circuit diagram showing an embodiment of an electronic device driving circuit according to the present invention. Note that here, the description will be given as an electronic device drive circuit used in an electronic device inspection system.

In FIG. 1, 10 is a driver, which includes diode bridges 12 and 14 as electronic switches, PNP bipolar transistors 16 and 18 and NPN bipolar transistors 20 and 22 for controlling the same, and constant current sources 24 and 26. Become. Diode bridge 12.1
The nodes of the four pairs are connected to constant current sources 24 and 28 through bipolar I transistors 16 to 22, respectively, as shown.

28 and 29 are drive power supplies, and 30 is a termination power supply. One driving power source 29 is connected to the first voltage application terminal T1. (one node of diode bridge 12).

The other drive power source 28 and termination power source 30 are connected to the second voltage application terminal T2 of the driver 10 via an electronic switch 31.
(one node of the diode bridge 14) depending on the mode. This electronic switch 31
is capable of high-speed operation, and here it is a field effect transistor 31A.

31B.

PH, PH*, PL, and PL* are part of the drive control signal supplied to the electronic device drive circuit, and are respectively applied to the bases of the corresponding bipolar transistors 16 to 22 as shown. These signals cause the bipolar transistor 18.20 to
Or the bipolar transistors 18, 22 are turned on, and the bipolar transistors 18, 2 are turned on in the input mode.
2 is turned on.

Ilo and the Ilo tree are also part of the drive control signal. This signal turns on the field effect transistor 31B in the output mode, selects the driving power source 28, and connects it to the electric current application terminal f'T2. Dairikimo 1! At times, the field effect transistor 31A is turned on, and the termination power source 30 is selected and connected to the voltage application terminal T2.

Output terminal T3 of driver IO (diode bridge 1
2 and 14 phase II:) is connected to a resistor (e.g. 50Ω) for impedance matching and termination.
32 and the reliable transmission line 34 (for example, the characteristic impedance is 5
It is connected to the pin connection terminal 36 via a microstrip line (0Ω microstrip line).

Next, the operation of this electric device drive circuit will be explained.

First, let me explain about the output mode (drive mode).
The complementary signal PH (7) and the PH* signal or the PL signal and the PL* signal are turned on at the same time.

For example, when the PH signal and the PH* signal are turned on at lO-, the bipolar transistors 18.22 are turned on at the same time, and the constant current sources 24.26 bias each diode of the diode bridge 14 in the forward direction. Therefore, the power supply terminal −J′ T 2 is connected to the output terminal T 3 via the diode bridge 14 .

In this output mode, the field effect transistor 31B is turned on by the I10 signal, and the voltage application terminal T2
Since the driving power source 28 is connected to the electronic switch 31, the voltage corresponding to the output voltage is applied to the output terminal '.
j'T3, this voltage is applied as a pin drive voltage to the pin of the electronic device connected to the pin connection terminal 36.

When the PL signal and the PL* signal are turned on, the bipolar transistors 16 and 20 are turned on, and each diode of the diode bridge 12 is forward biased, and the voltage applied to the power supply terminal Tl, that is, the output voltage of the driving power supply 29, is applied. A corresponding drive voltage is output at the output terminal YT3, and this drive voltage is applied to the electronic device pin connected to the pin connection terminal 36.

In this way, in the output mode, the termination power supply 30 is separated from the output of the driver 10 by Q], so that the pin drive voltage J1 has an adverse effect as if the termination power supply were always connected.
It's not as good as that.

In the input mode, the pH (, i, and PH* signals are turned on, so the voltage application terminal -T2 is connected to the output terminal J'T3 via the diode bridge 14. Also, I10*
The field effect transistor 31A is turned on by the signal, and the termination power supply 30 is connected to the voltage application terminal T2. Therefore, the voltage 1F corresponding to the output voltage of the termination power source 30 is output to the output terminal T3 of the driver 10, and the pin of the electronic device connected to the pin connection terminal 36 is terminated.

In this way, the output signal of that pin will be checked by a comparator or the like.

When testing a high-speed r device such as an ECL device, mode switching as described above is performed at high speed.

Conventionally, it has not been possible to connect and disconnect the termination circuit in synchronization with such high-speed mode switching, but this is possible with the electronic device drive circuit. Therefore, even the human output pins of high-speed electronic devices such as ECL devices can be driven by performing necessary termination and applying a normal drive voltage waveform.

In addition, since the termination circuit is not connected in parallel to the pin connection terminal 36, the electrostatic charge seen from the pin connection terminal 36 is reduced, and the drive voltage waveform, pin output signal, and waveform distortion are reduced accordingly. Inspection accuracy will improve.

Although one embodiment has been described above, the present invention is not limited thereto, and can be implemented with appropriate modifications.

Furthermore, it goes without saying that the present invention can be similarly applied to electronic device drive circuits used for applications other than electronic device testing systems.

[Effects of the Invention] As described in detail below-1, the electronic device drive circuit according to the present invention has a first voltage application terminal and a second voltage application terminal. It outputs a voltage corresponding to the applied voltage of the application terminal, and also outputs a voltage corresponding to the applied voltage of the second voltage application terminal at 12 o'clock in the input mode.
interposed between a driver that outputs one voltage, a first driving power source connected to the first voltage applying terminal, a second driving power source, a terminating power source, and a second voltage applying terminal; 11. When the second drive power source is in the second mode. ．． An impedance inserted between an electronic switch connected to the application terminal I and connecting the terminating power supply to the second voltage application terminal in input mode, and a pin connection terminal to which the output of the driver and the pin of the electronic device are connected. Since the configuration is equipped with matching and termination resistors, it is possible to perform the necessary termination for the input/output pins of electronic devices such as ECL devices that require high-speed mode switching, and to maintain normal operation without any effects from termination. It can be driven by applying a driving voltage, and the electrostatic 8 eyes seen from the pin connection terminal can be reduced compared to before, and the pin driving voltage waveform and pin output signal waveform can be changed, all of the conventional problems have been solved. Accordingly, it is possible to realize an electronic device drive circuit that has the following characteristics.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an electronic device driving circuit according to the present invention, and FIG. 2 is a schematic circuit diagram showing a conventional electronic device driving circuit. ...Diode bridge, 24.26... Constant current source, 28.29...
Drive power supply, 30... Termination power supply, 31... Electronic switch, 32... Impedance matching and termination resistor, 34... Signal transmission path, 36... Pin connection terminal.

Claims (2)

[Claims] (1) A drive circuit for an electronic device that has a pin that requires termination, has first and second voltage application terminals, and corresponds to the voltage applied to the first or second voltage application terminal in output mode. a driver that outputs a voltage corresponding to the voltage applied to the second voltage application terminal in the input mode; a first driving power source connected to the first voltage application terminal; 2, the second driving power source is connected to the second voltage applying terminal in the output mode, and the second driving power source is connected to the second voltage applying terminal in the input mode. an electronic switch for connecting a termination power supply to the second voltage application terminal; and an impedance matching and termination terminal inserted between the output terminal of the driver and a pin connection terminal to which a pin of an electronic device is connected. An electronic device drive circuit comprising a resistor. (2) The electronic device according to claim 1, wherein the driver selectively connects the output terminal and the first and second voltage application terminals using an electronic switch. Device drive circuit.