JP2635059B2 - Current load / voltage driver circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technique of the Invention] In the present invention, in order to evaluate the voltage and current DC characteristics of each element of a circuit element to be measured in an integrated circuit measurement, each terminal of the circuit element to be measured is Provides measurement waveforms, etc.
A current load for loading a current or the like into the circuit element to be measured;
The present invention relates to a voltage driver circuit.

[Prior art and its problems]

For example, in the measurement of the DC characteristics of an integrated circuit, voltage application / current measurement (mainly an input terminal) or current application / voltage measurement (mainly an output terminal) is performed according to the specifications of a terminal of a circuit element to be measured. Conventionally, in a test head section for connecting such circuit element terminals to be measured, units each mainly comprising a comparator C ₄ , a current load L ₄ , and a voltage driver D ₄ are provided at each terminal as shown in FIG. Can be In actual measurement, in such draws current from the output terminal of the circuit under test element, and connecting a current load L _4, comparison, determination performed at a given threshold and the comparator C _4. On the other hand, in such supplies a predetermined voltage to the input terminal of the circuit under test element, is connected with a voltage driver D _4, to discriminate by the comparator C _4.

In recent years, there has been an increasing demand for downsizing of the test head section, and thus a higher density of the units provided for each terminal is required. In addition, current load L ₄ and voltage driver D ₄
Are used in different measurement situations, and therefore coexist and consume wasteful power when not in use.

[Object of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, reduce the number of units in a test head unit, and provide a current load / voltage driver circuit integrated in a high density hybrid integrated circuit.

[Summary of the Invention]

In one embodiment of the present invention, as shown in FIG. 1, in order to evaluate an integrated circuit, a voltage driver for applying a desired voltage waveform to each terminal and a current load function for loading a desired current to each terminal And a current load / voltage driver circuit comprising switching means for switching between them.

(Example of the invention)

FIG. 2 shows a current load, which is a preferred embodiment of the present invention.
3 shows a voltage driver circuit. First, a conventional current load will be briefly described in order to make the description of the present embodiment easy to understand.
Normal current load and L ₅ in FIG. 5, mainly composed of a bridge circuit formed from the current source 51 and current sink 52 and four diodes D ₅₁ to D _54. These two positive and negative power supplies are programmable, each of which can be set to any value. This is because the output voltage value of the measured, by setting an arbitrary threshold voltage V _T, it is possible to switch the current applied extraction of (current source 51) or current (current sink 52). This embodiment includes two programmable power supplies, a current source 21 and a current sink 22 and two sets of diode bridge circuits B ₂₁ and B ₂₂ , and a switching means for realizing a current load function and a voltage driver function. Provided. In current load mode, the ON only the transistor Q _21, Q _24, L _Ref voltage becomes the threshold voltage V _T in Figure 5. As described above, the circuit element under test (not shown) is loaded with a positive or negative current from the current source 21 and the current sink 22 via the load resistor R. In the voltage driver mode, the current source 21
When the current sink 22 is set to its maximum value and the output voltage of the circuit is set to the low reference voltage L _Ref , the transistors Q ₂₁ and Q
Turns ON only _24, also the output voltage when the high reference voltage H _Ref switches so that ON only the transistor Q _23, Q _26. In addition, by turning ON only the transistors Q ₂₂ and Q ₂₅ , either of the diode bridge circuits B ₂₁ and B ₂₂
By preventing the current from flowing, the output can be set to a high impedance mode. These ON / OFF operation of the transistor Q ₂₁ to Q ₂₆ are well known in the art, where the description is omitted, nor particularly limited. In this embodiment, a transistor is used as the switching means. However, for example, another switching element such as an FET can be used.

Note that the resistor R connected to the output is used as an output matching resistor of the voltage driver. In high-speed circuits,
If the output is zero voltage, it can be used as a termination of an external circuit.

FIG. 3 shows pin electronics of an integrated circuit measuring device, and a method of determining a circuit element to be measured will be described below as an application example. In the pin electronics, and the current load voltage driver circuit D / L ₁ is used in the present invention, the current source or voltage source in a direct current as well, is also used as a pulse driver exceeding 100 MHz. In the following description, the current source D /
Shows a case of operating as L _1.

Pins P ₃₁ , P ₃₂ , .., P _3k , .., P _3n are respectively connected to each lead of the circuit element under test (not shown) to drive each lead or measure the signal on each lead. Or used to do so. Pin electronics PE ₃₁ , PE ₃₂ , .., PE _3k , .., P
E _3n are provided one by one, and have substantially the same configuration. Hereinafter, the pin electronics PE ₃₁ will be described in detail. The pin electronics PE ₃₁ operates under the control of an external controller (not shown). Switch S ₃₁ connects the pin P ₃₁ S _31a, to one of S _31b. Switch S
Connection ₃₁ and the current load voltage driver circuit D / L ₁ can also be performed as in the first view. In that case it is sufficient to cut the input of the voltage comparator C ₃₁ at point X so as to be connected to P _31. Pin P ₃₁ is pin P ₃₁ is energized by a current D / L ₁ when connected to the S _31a. Voltage on pin p ₃₁ by the voltage comparator C ₃₁ is compared with two different thresholds, Purippu-by magnitude relationship (HT, shown in LT signal) the strobe signals S ₁ from the external controller for each threshold
Launched at Prop FF. The latched signals HT ₁ ′ and LT ₁ ′ corresponding to HT ₁ , LT ₁ , respectively, are input to the comparison logic CL ₁ to determine whether the signal is higher than the high level threshold, lower than the low level threshold, or both. Output H1, L depending on the level between thresholds
1 and W1 are each at a high level. The multiplexer MUX receives the output H1, L1, W1, and outputs a pass / fail signal (referred to as PF signal) Wired OR circuit PF ₁ by pre-determined criteria. On the other hand, the contents of the output H1, L1, W1 is latched in the status register SR, it is read from the output SRO ₁ to the data bus DB.

If the pin electronics is connected to pin P ₃₁ to S _31b, the output voltage of the programmable voltage source V ₁ is applied to the pin P _31, the current value flowing into the pin P ₃₁ is the current comparator C ₃₂ and two thresholds Be compared. Data output to the comparison output of the processing and Wired OR circuitry PF ₁ and status register output SRO as well as the output of the voltage comparator C ₃₁ described _{above, HT 2, LT 2, FF} , HT 2 ', LT 2', CL ₂ , H2, W2, L2, MU
X, SR is achieved by performing _{HT 1, LT 1, FF,} HT 1 ', LT 1', CL 1, H1, W1, L1, SR operation of each. The pin electronics PE ₃₁ , PE ₃₂ , .., PE _3k , .. PE _3n are divided into several groups, and all the wired-OR circuits of each group are connected to one input of the pass / fail register PFR. Notify if there is any rejected output in no applicable group.

The external controller examines the contents of the register PFR and, if a failing group is found, reads the contents of each status register that serially polled the pin electronics in that group. In this way, the state of the pin electronics that provided the failed output is notified to the external controller.

In the present embodiment, the measurement of the packaged integrated circuit has been described in detail. However, the present invention can be applied to, for example, evaluation of each terminal of the integrated circuit such as a wafer state.

〔The invention's effect〕

As described above, the current load according to the present invention is
The voltage driver circuit is reduced in size and power consumption by combining the conventional separate unit elements, thus greatly contributing to cost reduction.

Further, in the present circuit, the accuracy of the integrated circuit measurement is improved by reducing the parasitic capacitance generated in the relay connected to the comparator.

In addition, miniaturization enables a configuration of pin electronics with a high degree of freedom.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a current load / voltage driver circuit according to one embodiment of the present invention. FIG. 2 is a circuit diagram of a current load / voltage driver circuit according to one embodiment of the present invention. FIG. 3 is a configuration diagram of pin electronics using the current load / voltage driver circuit of the present invention. FIG. 4 is a diagram showing a conventional current load and voltage driver unit configuration. FIG. 5 is a circuit diagram of a conventional current load. C _1, C _4: Comparator, L _4: current load, D _4: current driver, 21, 51: current source, 22 and 52: a current _{sink, PE 31, PE 32, ..} , PE 32, .., PE _3k , .., PE _3n : Pin electronics.

Claims (2)

(57) [Claims] In a characteristic measurement of a circuit element having a plurality of terminals, two diode bridge circuits connected to two programmable power supplies and a reference voltage, and switching means for switching connection between the two power supplies, A diode bridge circuit and a load resistor connected to the terminal, wherein the switching means switches and connects one of the diode bridge circuits to the programmable power supply and the load resistor, and a desired current is supplied to the circuit element. Providing means for loading a terminal, alternately switching the diode bridge circuit to the load resistor, and providing means for alternately applying two different voltages to the terminal. Current load and voltage driver circuit. 2. The current load according to claim 1,
A current load / voltage driver circuit in a voltage driver circuit, wherein said switching means is operated to switch and ground said two power supplies, thereby providing means for applying a high impedance to said terminal.