JPH01152378A - Semiconductor apparatus - Google Patents

Abstract

PURPOSE:To easily detect a leak current by an external terminal even when a weak leak current is generated, by mounting the diode connected between the emitter electrode of a transistor and the external terminal in series. CONSTITUTION:When power supply voltage Vcc is applied to a power supply terminal in such a state that an external terminal EXT is earthed, a current flows through a route composed of power supply terminal (to which power supply voltage Vcc is applied) resistor R3 collector emitter of transistor Q1 diode D3 EXT terminal if any resistance component is present between the collector and emitter of the transistor Q1 and, therefore, said current can be measured at the EXT terminal. At this time, not only in such a case that the resistance component present between the collector and emitter of the transistor Q1 is relatively small but also in such a case that only a weak current flows because of the presence of high resistance, a leak current can be measured from the EXT terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device whose circuit is constituted by a plurality of transistors.

[Conventional technology]

In recent years, technological innovations in semiconductor devices have been remarkable.In addition to individual semiconductors such as diodes and transistors, integrated circuits (hereinafter referred to as I
In the field of (referred to as C), there is a remarkable trend toward higher integration, and along with this, miniaturization of diffusion processes is progressing. There are various problems caused by process miniaturization, but
One of them is the problem of element leakage.

In particular, the problem of transistor leakage cannot be ignored.
If the amount of leakage is large, it will naturally affect the actual operation of the transistor, but even in the case of a small amount of leakage that does not affect the operation of the transistor, ICs that integrate a large number of transistors will be affected. This poses a disadvantage in terms of power consumption.

FIG. 3 is a circuit diagram of an example of a conventional semiconductor device, showing a DTL inverter circuit composed of bipolar transistors.

In Figure 3, Ql and Q2 are NPN transistors, DI and D2 are diodes, R1°R2 and R3 are resistors,
VCC represents the power supply voltage, and IN and OUT represent the input and output terminals of this circuit, respectively. Here, a case will be described in which the output terminal OUT is taken out as an external terminal. ' In the circuit shown in Fig. 3, the voltage applied to the input terminal IN is a voltage higher than the threshold value (1.6 V in this circuit, assuming the forward conduction voltage of diode D1 is 0.8 mm);
For example, if the voltage is 3V, the transistor Q1. Q2 is also in a conductive state, and output terminals 0. UT is low level (about 0.2V)
When the voltage applied to the input terminal IN is set to be less than a threshold value, for example OV, both transistors Ql and Q2 become non-conductive, and the output terminal 0tJT operates at a high level.

Here, consider an operation in which the voltage applied to the input terminal IN is set to a voltage below a threshold value and the output terminal OUT is set to a high level. At this time, for some reason, a resistance component exists between the collector and emitter of transistor Q2,
If leakage current flows, it can be easily checked from the output terminal OUT. However, if there is a resistive leak as described above between the collector and emitter of the transistor Q1, if the resistance value is small and the leak current is large to some extent, the base current is supplied to the transistor Q2, and the transistor Q2 becomes conductive. - state and the output terminal OUT becomes a low level, so it is possible to check for abnormalities in the characteristics at the output terminal, but if the resistance value is large and only a small leakage current flows, the transistor Q2 will not become conductive. Naturally, checking from the output terminal becomes impossible.

Furthermore, in the case of a slight leak, looking at the characteristics between the power supply voltage and ground, in FIG.
Since the current path between the resistor R2 and the ground is much larger than the leakage current, the minute leakage current between the collector and emitter of the transistor Ql cannot be measured. In any case, the minute leakage current as mentioned above is caused by the input terminal IN and the output terminal O.
No abnormality can be detected in the characteristics between the UT, power supply voltage VCC, and ground, and even if the small leakage current flowing through the many transistors in the IC does not lead to malfunction, it is not desirable from the viewpoint of power consumption etc. No, no.

[Problem that the invention seeks to solve]

In the conventional semiconductor device described above, even if a small leakage current flows between the collector and emitter of the transistor Q1,
The drawback is that leakage current cannot be detected no matter which characteristic is measured.

[Means for solving problems]

A semiconductor device of the present invention includes a leakage current measuring circuit including a diode connected in series between an emitter electrode of the transistor and an outer terminal.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit diagram of a first embodiment of the present invention.

As shown in FIG. 1, a diode D has a cathode connected to an input terminal IN, and a diode D has one end connected to a power supply terminal of a power supply voltage VCC and the other end.

an NPN transistor Q1 whose base is connected to the anode of the diode D1, and a resistor R3 whose one end is connected to the power supply terminal and the other end is connected to the collector of the transistor Ql. Diode D2 whose anode is connected to the emitter of transistor Q1
and an NPN type transistor Q2 whose base is connected to the cathode of the diode D2, whose collector is connected to the output terminal 0tJT, and whose emitter is connected to the ground terminal, and one end is connected to the base of the transistor Q2 and the other end is connected to the ground terminal. and a leakage current measuring circuit CT whose anode is connected to the emitter of the transistor Ql and whose cathode is connected to the external terminal EXT.

In Figure 1, when external terminals F and XT are grounded and power supply voltage VCC is applied to the power supply terminal, if there is some resistance component between the collector and emitter of transistor Q+, then the power supply terminal of power supply voltage VCC - resistor R3) 'Since current flows through the path of the collector emitter diode D of the transistor Q and the -EXT terminal, it is possible to measure the current at the EXT terminal.

At this time, leakage current can be measured from the EXT terminal not only when the resistance component existing between the collector and emitter of transistor Q+ is relatively small, but also when only a small leakage current flows due to the presence of high resistance. It is.

In addition, in actual use, if you open the EXT terminal or apply a voltage lower than the reverse withstand voltage of diode D3 (usually 7 to 8 V) (for example, by connecting it to the power supply terminal)
, diode D, there is no current flowing in or out, so the circuit will not malfunction.

FIG. 2 is a circuit diagram of a second embodiment of the invention.

As shown in FIG. 2, in the second embodiment, the leakage current measuring circuit CT1 includes an NPN transistor Q3 and a resistor between the diode D3 of the first embodiment of FIG. 1 and the external terminal EXT. R4 and R5 are connected to diode D4.

In FIG. 2, when a high voltage, for example 12V, higher than the reverse breakdown voltage (approximately 7 to 8V) of the diode D4 is applied to the external terminal EXT, the base current of the transistor Q3 is supplied through the current limiting resistor R5, and the resistor R3 If Qs is set to an appropriate value, the transistor Qs becomes conductive. At this time, when power supply voltage VCC is applied to the power supply terminal, if some resistance component exists between the collector and emitter of transistor Q1, the power supply terminal - resistor R1 - transistor Q
Since current flows through the path from the collector-emitter diode D-4 of I to the collector-emitter ground terminal of the transistor Q3, leakage current can be measured by changing the voltage value of the power supply voltage VCC.

In the second embodiment, even if a voltage equal to or lower than the reverse breakdown voltage of the diode D4 is applied to the external terminal EXT, the transistor Q3 does not become conductive. has the advantage that it can also be used as an input terminal that uses an input voltage of 0 to 5 V).

〔Effect of the invention〕

As explained above, the semiconductor device of the present invention has a relatively high resistance component between the collector and emitter of a transistor, and even if a small leakage current occurs, the leakage current can be easily detected by the external terminal. be. Furthermore, the effect that the external terminal can also be used as another input terminal can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first embodiment of the invention, FIG. 2 is a circuit diagram of a second embodiment of the invention, and FIG. 3 is a circuit diagram of an example of a conventional semiconductor device. CT, CT, . . . leakage current measurement circuit, Dl. Dl, DS, D4...Diode, EXT...External terminal, IN...Input terminal, OUT...Output terminal, Q
l. Q2. Q9...NPN type transistor, R1°R2
, Rq, R4, R<...resistance, vcc...power supply voltage. Agent Patent Attorney Uchihara Phoneme 1 Figure 2

Claims (1)

[Claims] What is claimed is: 1. A semiconductor device in which a circuit is constituted by a plurality of transistors, comprising a leakage current measuring circuit including a diode connected in series between an emitter electrode and an outer terminal of the transistor.