JPS63277423A - Integrated circuit - Google Patents

Abstract

PURPOSE:To increase dielectric strength against the noise of a power source, by arranging a constant-voltage circuit generating specified constant voltage, and a limiter circuit limiting the power source to the range of working line voltage or higher and withstand voltage or lower. CONSTITUTION:On a power line to an element 39 and the like composing an integrated circuit, a limiter circuit 11, a starting circuit 12, a constant-voltage circuit 13, and a constant-current circuit 14 are built integrally with the integrated circuit. When line voltage Vcc exceeds the Zener voltage of a Zener diode 17, then the Zener diode 17 turns conductive to make a transistor 16 conductive, and voltage fed to the circuits is limited. From the starting circuit 12, current is fed to a Zener diode 28, and the constant-voltage circuit 13 is started. From the constant-voltage circuit 13, based on the Zener voltage of the Zener diode 28, constant voltage is fed to the integrated circuit elements.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to characteristics of power supply voltage and power supply current of an integrated circuit.

[Conventional technology]

FIG. 7 is a circuit diagram showing the main parts of a conventional integrated circuit as shown in, for example, the Mitsubishi General-Purpose Linear IC User's Manual (P2-45) J published by Mitsubishi Electric Corporation. In the figure, (1) is the collector It is a high resistance called a pinch resistance and has constant current characteristics as shown in Figure 8, but because its value varies widely, it is used to drive the circuit. (21 (31 (41 (91 GO) It is an NPN type transistor, transistor (2) (3I (91
is used as a diode by shorting its base and collector. (61 (71[81 is a PNP type transistor, and the transistor (6) is used as a diode by shorting its base and collector. ((5)
is a resistance called the base resistance, which is made by the same diffusion as the base of an NPN transistor.

A conventional integrated circuit is constructed as described above, with the positive power supply line V
When cc rises, resistor (1), transistor (2) (
A current flows through the transistor (21), and the base potential of the transistor (21) becomes approximately 1.2V with respect to the negative power supply line GND (=OV).

This is connected to the base of the transistor (A), and a resistor (9) is inserted between the emitter of the transistor (A) and GND, so a voltage drop of approximately 0.6V will occur across the resistor (5). A current flows, which becomes the collector current of the transistor (4) and further flows to the transistor (6).Since the I transistor (7) is connected in a current mirror with the transistor (6), the transistor (7) has a collector current. A collector current of approximately the same magnitude as that of transistor (6) flows, and this becomes a source of a constant current source.In addition, the transistor (8) is also connected in a current mirror with the transistor (6), and its collector current becomes a constant current and acts as a constant current source. (9). Transistor QOI is connected to transistor (9) in a current mirror connection, and almost the same collector current as transistor (00) flows through transistor (9), and this becomes a sinking constant current source. The integrated circuit operates with this constant current source. Power supply current at this time
The voltage characteristics are almost constant current characteristics as shown in FIG.

[Problem that the invention seeks to solve]

In conventional integrated circuits such as those mentioned above, if noise with a voltage exceeding the withstand voltage jumps into Vcc, that voltage may be applied as is and the circuit may be destroyed, so care must be taken to prevent Vcc from exceeding the above withstand voltage. There is a problem in that it is necessary to take measures such as inserting a capacitor or Zener diode between Vcc and GND to reduce the circuit.Also, even if the current is constant, if Vcc fluctuates, the operating state of the element changes. There is a problem in that the operating state of the integrated circuit also fluctuates slightly because the voltage also fluctuates slightly.

This invention was made to solve this problem, and when it comes to noise that exceeds the withstand voltage of the integrated circuit, it absorbs the energy of the noise and suppresses the increase in νCC due to the noise to below the withstand voltage. By doing this, we can obtain an integrated circuit that will not be destroyed even if there is no noise suppression measures outside the integrated circuit, and the circuit operation of the circuits that perform the main functions of the integrated circuit can be stabilized by stabilizing the circuit voltage. The purpose of this invention is to obtain an integrated circuit as described above.

[Means for solving problems]

The integrated circuit according to the present invention includes a constant voltage circuit that generates a predetermined constant voltage, and a limiter circuit that limits the power supply to a voltage that is above the operating power supply voltage range and below the withstand voltage.

[Effect]

In this invention, the increase in the power supply voltage Vcc of the integrated circuit due to noise etc. is suppressed to a predetermined voltage, and the energy of the noise etc. is passed as a current to prevent damage to the integrated circuit. It supplies constant voltage to circuits that perform major functions, making the circuit operations stable.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which (11) is a limiter circuit, (12) is a starting circuit, (13) is a constant voltage circuit, (i4) is a constant current circuit, (1
5) is a circuit that performs the main functions of an integrated circuit, (+6
1 <20) (21) (22) (29) (32
) (35) (36) (37) are NPN transistors, (17) (28) are Zener diodes, (
+8) (23> (38) is the resistance, (19) is the collector pinch resistance, (24>(25>(26> (27)
) (30) <31) (33) <34) (39
) is a PNP type transistor. Figure 2 is a diagram showing the characteristics of power supply current 1cc and constant voltage Vconst with respect to power supply voltage νCC in the circuit of Figure 1, where Vl~v2 is the operating voltage range, v3 is the withstand voltage of the integrated circuit, and v4 is the limiter circuit limit. Voltage, v5 is constant voltage Vconst above
is the stable voltage.

In the integrated circuit configured as described above, the Zener diode (17) of the limiter circuit (11) has a Zener voltage that is higher than the working voltage range (more than ■2 in Figure 2) and less than the withstand voltage v3 of the integrated circuit. The voltage is set near v4, and when Vcc is lower than v4, the limiter circuit (11
) does not work. When Vcc rises to around v4, the Zener diode (17) becomes energized and the transistor (16)
operates and draws current from Vcc, so Vcc does not rise above around v4. When Vcc is applied to the startup circuit (12), the resistor (19)) transistor (20) (2
1) and the base potential of the transistor (22) is raised to about 1.2V, so that the ulator current of the transistor (22) flows so that the voltage drop across the resistor (23) is about 0.6V. The current is the transistor (25)
It also becomes the collector current of transistor (25) and transistor (24) (26) connected to the current mirror.
) (27) also has a collector current of approximately the same magnitude. The collector current of transistor (24) is
0), increases the current, and increases the current to the transistors 1 to 22 (22).
) to stabilize the base voltage. Transistor (26)
The collector current of (27>) is used to start up other circuits. In the constant voltage circuit (13), the Zener diode (28) is turned on by the collector current of the transistor (27).

The Zener voltage of the Zener diode (28) is
15) is set higher than required. For example, if the Zener voltage is about 7.6V, when the Zener diode (28) is energized and stabilized, the transistor (2
The base voltage of 9) is approximately 7.6V, and its emitter voltage, that is, the constant voltage V generated by this constant voltage circuit (13).
const is about 7. Become Ov. Transistor (29)
has the function of supplying the base current of the transistor (32) by turning it around the transistor (30) (31>), and most of the load current of Vconst is supplied through the transistor (32). Voltage circuit (14)
receives the collector current of the transistor (26), and
The operation starts when Vconst rises.

The collector current of the transistor (26) flows, the base potential of the transistor (37) becomes approximately 1.2V, and the resistor (
The collector current of the transistor (37) flows so that the voltage drop across the transistor (38) becomes approximately 0.6V, which also becomes the collector current of the transistor (34), and also flows into the transistor (33) which is connected as a current mirror. A collector current of the same magnitude is generated and flows into the transistor (35) to stabilize the base potential of the transistor. The circuit (15) is a circuit that performs the main function of each integrated circuit and differs depending on the integrated circuit. The transistor (39) represents a case in which a constant current is required in the circuit (15), and is connected in a current mirror with the transistor (34) to discharge a collector current of approximately the same magnitude as the transistor (34). When the circuit (15) is configured based on constant current, the circuit current becomes more stable when VconsL becomes stable, and is stable even before Vconst rises. Further, if the circuit (!5) is a resistive load, its circuit current becomes stable when Vconst stabilizes, but before Vconst rises, it fluctuates in proportion to fluctuations in Vcc.

Power supply voltage Vcc, power supply current 1cc, and constant voltage Vcons
As shown in Figure 2, the characteristics of t are as follows: Vconst is Vcc
It starts up at =V5 and stabilizes above that. Tcc is V
If cc=V5 or less, the stability is somewhat poor, but if it is more than that, it becomes stable. However, the reason why it tends to increase slightly is because the current in the starting circuit (12) increases. And Vcc=V
When the voltage reaches 4, the limiter circuit (11) operates, Icc increases rapidly, and the rise in Vcc is suppressed.

In the above embodiment, a single transistor was used for the limiter circuit (11), but it may be a Darlington transistor as shown in FIG. 3(a), or a Zener diode (17) as shown in FIG. 3(b). ) may constitute the limiter circuit (11). In FIG. 3(a), (40) is an NPN type transistor, which together with the transistor (16) constitutes a Darlington.

In addition, the circuit consisting of (20) to (23) of the starting circuit (12) and (35) to (38) of the constant current circuit (14) may be the circuit shown in FIG. )
(43) is an NPN transistor, (44) is a resistor, and when a current flows to the collector side of the transistor (42), the transistor (43) is biased and current flows to the base side of the transistor (42). When the voltage drop across the resistor (44) reaches approximately 0.6V, the transistor (42) is biased and a collector current flows, which reduces the base current of the transistor (43), causing negative feedback and stabilizing in a certain state. The collector current of the transistor (43) is such that the resistance (44) is about 0.6V.

Furthermore, the constant current circuit (13) connects the base of the transistor (32) to the cathode of the Zener diode (28) as shown in FIG.
(31) may be omitted.

Furthermore, in the above embodiment, the Vcc of the integrated circuit is directly connected to the external power supply Vcc', but a resistor (45) is connected between them outside the integrated circuit as shown in FIG. This allows even noise that has energy greater than the current capacity of the limiter circuit 11) and that would destroy the integrated circuit that directly enters Vcc to be directly connected to Vcc.
If the current flows into the limiter circuit (11) due to the voltage drop of the resistor (45) and becomes less than the current capacity of the limiter circuit (11), the integrated So the circuit can survive.

〔Effect of the invention〕

As explained above, this invention is equipped with a constant voltage circuit that generates a predetermined constant voltage and a limiter circuit that limits the power supply to a voltage above the working power supply voltage range and below the withstand voltage. The breakdown strength against noise such as the like is improved, and there is no need to provide a capacitor or a Zener diode outside the integrated circuit to protect the integrated circuit against noise with an energy lower than that allowed by the limiter circuit. In particular, in an integrated circuit in which the power supply current is stabilized, a high voltage such as Vcc is directly applied to Vcc, so providing a limiter circuit has a great effect. Furthermore, by creating and supplying the minimum necessary constant voltage to power the circuits that perform the main functions of integrated circuits, it is possible to further suppress the effects of power supply voltage fluctuations and noise, etc. There is an effect that can be done.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing the power supply current and constant voltage characteristics with respect to the power supply voltage in FIG. 1, and FIG. FIG. 4 is a circuit diagram showing still another embodiment of the invention; FIG. 5 is a circuit diagram showing still another embodiment of the invention; FIG. 6 is a circuit diagram showing still another embodiment of the invention. 7 is a circuit diagram showing a conventional integrated circuit, FIG. 8 is a diagram showing the constant current characteristics of the high resistance (1) in FIG. 7, and FIG. 9 is a circuit diagram showing still another embodiment of . It is a diagram showing the current/voltage characteristics in Fig. 7. In the figure, (11) is a limiter circuit, and (13) is a constant voltage circuit.

Claims (1)

[Claims] An integrated circuit that includes a constant voltage circuit that generates a predetermined constant voltage and a limiter circuit that limits the power supply to a voltage that is above the operating power supply voltage range and below the withstand voltage.