JPS61276007A - Stabilizing voltage supplying circuit - Google Patents

Abstract

PURPOSE:To avoid the lateral transistor, executing saturating action by provid ing stabilizing and the voltage control and electric current control parts, to operate in accordance with the emitter collector voltage or electric current of the lateral transistor. CONSTITUTION:When an output voltage V0 is changed, a comparing circuit part 20 generates the output in accordance with the voltage change, in accordance with it, a transistor Tr 15 is operated, the voltage between emitter bases of a lateral transistor Tr 13 is changed and the change of the voltage V0 is suppressed. A Tr 34 detects the voltage between emitter collectors of the Tr 13 to receive the control by the Tr 15, operated in accordance with the detecting voltage, and when an input voltage V1 is decreased to the prescribed value or below, the voltage obtained at the collector of the Tr 13 is reduced, and the voltage between emitter collectors of the Tr 13 is kept to the prescribed value or above. A Tr 36 detects the emitter collector passage electric current of the Tr 13, operates in accordance with it, and even when the collector voltage of the Tr 13 is reduced by the Tr 34, an the emitter collector passage electric current of the Tr 13 is limited to the prescribed value or below.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a series-type stable overvoltage supply circuit in which a lateral transistor is used as a control transistor connected between input and output terminals.

(Summary of the Invention) The present invention provides a stable overvoltage supply circuit configured in series in which lateral transistors are used as control transistors connected between input and output terminals. operates,
a voltage control unit that controls the voltage obtained at the output terminal of the lateral transistor in order to keep it above a predetermined value;
By providing a current control section that operates according to the emitter-collector path current of the lateral transistor and controls to keep it below a predetermined value, the voltage supplied to the input side terminal of the lateral transistor decreases. Accordingly, it is possible to prevent the lateral transistor from operating in the saturation operation region, and to prevent excessive current from flowing through the lateral transistor.

(Prior art) In the field of electronic circuit technology, integrated circuits are being developed over a very wide range of areas, and even when configuring circuits that supply a relatively low stabilized DC voltage as a power supply voltage, Integrated circuit devices have been applied. For example, a series-type stable overvoltage supply circuit that uses a PNP transistor as a control element and is integrated into an integrated circuit has been proposed.
The PNP transistor in such a case is a lateral transistor.

FIG. 2 shows a conventionally proposed series type stable overvoltage supply circuit in which a lateral PNP transistor is used as a control transistor. In this circuit, an emitter is connected to an input terminal 11 to which an unstabilized input voltage Vi is supplied, and an output voltage V to be stabilized.
A lateral PNP transistor 13 whose collector is connected to the output terminal 12 from which o is sent out is provided with a resistor 14 between the emitter and the base.
A PNP transistor 15 forming a stabilization control for the transistor 13 is connected to the base of the transistor 13 .

Then, the output voltage Vo obtained at the collector of the transistor 13 is detected as a voltage Vo' obtained by dividing the voltage by the resistors 16 and 17, and this voltage Vo' is connected to the collector of the transistor 13 via the resistor 18. The reference voltage Vr obtained by the constant voltage source 19 is supplied to the comparator circuit section 20 . The comparison circuit section 20 has a voltage Vo'
and a reference voltage Vr are supplied, respectively) A differential section formed by transistors 22 and 23 and a constant current source 24, and resistors 25R and 26R and P that serve as a load for this differential section.
NP) consists of a part of a current mirror formed by transistors 25, 26, and 27, and supplies a current between the transistors 23 and 26 according to the comparison result between the voltage Vo' and the reference voltage Vr. Connected NPN
Pour into the base of the I-transistor 28. A constant current source 29 is connected to the emitter of the transistor 28, and the base of the transistor 15 is also connected to the emitter of the transistor 28. Therefore, the base current of the transistor 15 is connected to the emitter of the transistor 28.
is assumed to decrease as the collector-emitter path current increases.

Under such a configuration, for example, the normal value of the input voltage Vi is 5.times., whereas a stabilized output voltage of 4.2 V, .times.0, is obtained. The output voltage VO is equal to the input voltage Vi
For example, if the output voltage Vo increases, the voltage Vo' obtained at the connection point between the resistors 16 and 17 increases, thereby creating a state in which the collector-emitter path current of transistor 22 increases and the collector-emitter path current of transistor 23 decreases. Since the emitter-collector path currents of transistors 25 and 26 are made equal by current mirror operation, the base current of transistor 28 increases as the collector-emitter path current of transistor 23 decreases. . As a result, the collector-emitter path current of transistor 28 increases, and the base current of transistor 15 decreases accordingly. Therefore, the emitter-collector path current of the transistor 15 decreases, the voltage across the resistor 14 decreases, and the emitter-base voltage of the transistor 13 decreases. As a result, the emitter-collector impedance of the transistor 13 increases, and the output voltage (2)0 is lowered, and as a result, the increase in the output voltage Vo is suppressed.

Furthermore, if the output voltage VO decreases, the current and voltage of each part will change in the opposite relationship to the above, and the emitter-collector impedance of the transistor 13 will decrease, causing the output voltage 0 to increase. become,
As a result, the drop in the output voltage 0 can be suppressed.

In this way, even if there are fluctuations in the input voltage Vi or fluctuations in the load connected to the output terminal 12, if these are within a predetermined fluctuation range, the stabilized output voltage
0 is obtained.

(Problems to be Solved by the Invention) In the conventionally proposed series-type stable overvoltage supply circuit in which the control transistor is a lateral transistor as described above, when the input voltage Vi is changed from the normal value of 5V, for example, For example, if the output voltage Vo is 4.
．． Therefore, the input voltage Vi decreases and the output voltage V is stabilized.

, the lateral PNP transistor 13, which is a control transistor, is placed in a state where it operates in a saturation operating region. Lateral/PNP) If the transistor 13 is assumed to operate in the saturated operating region, then
A relatively large current will flow through the semiconductor substrate of the integrated circuit device including the transistor 13 due to the effect of the parasitic transistor formed in association with the transistor 13. and,
A relatively large current flowing through such a semiconductor substrate may lead to deterioration of the reliability of the integrated circuit device, and may also cause a large negative tE1 to be applied to the voltage source connected to the input terminal 11.
．． This will cause inconvenience.

In view of these points, the present invention provides that lateral transistors are used as control transistors connected between input and output terminals, are configured in series, and are configured in series to compensate for fluctuations in the input terminal supplied to the input terminals or as control transistors connected to the output terminals. It is possible to obtain a stabilized output voltage against load fluctuations, and
An object of the present invention is to provide a stable overvoltage supply circuit that can prevent a lateral transistor used as a control transistor from operating in a saturation operation region even when a drop in input voltage occurs. .

(Means for Solving the Problems) To achieve the above object, a stable overvoltage supply circuit according to the present invention includes a lateral transistor having an emitter-collector path connected between an input terminal and an output terminal; A comparison section that compares the output voltage obtained at the output terminal or a voltage obtained according to the output voltage with a reference voltage, and the output voltage is adjusted by controlling the emitter-base voltage of the lateral transistor according to the output of the comparison section. a stabilization control section that stabilizes;
a voltage control section that operates according to the emitter-collector voltage of the lateral transistor to control the voltage obtained at the terminal connected to the output terminal of the lateral transistor;
The voltage control section maintains the emitter-collector voltage of the lateral transistor at a predetermined value or higher, and the current control section operates according to the emitter-collector path current of the lateral transistor. Accordingly, the emitter-collector path current of the lateral transistor is limited to a predetermined value or less.

(Function) In the stable overvoltage supply circuit according to the present invention as described above, when the output voltage changes due to fluctuations in the input voltage supplied to the input terminal or fluctuations in the load connected to the output terminal, the comparison The section generates an output in response to a change in the output voltage, and the stabilization control section operates in response to change the emitter-base voltage of the lateral transistor, thereby suppressing the change in the output voltage. The voltage control section detects the emitter-collector voltage of the lateral transistor controlled by the stabilization control section and operates accordingly, and when the input voltage drops below a predetermined value, The current controller functions to lower the voltage obtained at the terminal connected to the output terminal of the lateral transistor so that the emitter-collector voltage of the lateral transistor is maintained at a predetermined value or higher; It detects the emitter-collector path current of the lateral transistor and operates accordingly, so that even in situations where the voltage control section reduces the voltage obtained at the terminal connected to the output terminal of the lateral transistor, the lateral It functions to limit the emitter-collector path current of the transistor to a predetermined value or less.

Therefore, according to the stable overvoltage supply circuit according to the present invention, it is possible to supply a stabilized output voltage even when there are fluctuations in the input voltage or fluctuations in the load, and moreover, when the input voltage is below a predetermined value. The emitter-collector voltage of the lateral transistor, which is a control transistor, is maintained at a predetermined value or higher even when the voltage decreases, and the lateral transistor does not operate in a saturation operating region, and
The emitter-collector path current of the lateral transistor is prevented from becoming excessive.

(Example) Examples of the present invention will be described below.

FIG. 1 shows an example of a stable overvoltage supply circuit according to the present invention. This example has parts configured similarly to the circuit shown in FIG.
Portions corresponding to the respective parts shown in the figures are shown with the same reference numerals as those in FIG. 2, and redundant explanation thereof will be omitted.

In the example shown in FIG. 1, a lateral PNP transistor 1 is a control transistor with an emitter-collector path connected between an input terminal 11 and an output terminal 12.
3 between the emitter and base of the resistor 14 shown in FIG.
Alternatively, resistors 30 and 31 are connected in series, and an NPN transistor 32 is connected at its base to the junction between resistors 30 and 31, and its collector is connected to the emitter of transistor 13. and its emitter is grounded via a resistor 33. Further, a PNP transistor 34 is provided with its base connected between the emitter of the transistor 32 and the resistor 33, its emitter connected to the collector of the transistor 13, and its collector grounded via the resistor 35, Furthermore, another NPN) transistor 36 whose base is between the collector of the transistor 34 and the resistor 35, whose collector is connected to the NPN) transistor 2
2 collectors, and their emitters are grounded.

The transistor 34 operates according to the emitter-collector voltage of the transistor 13 to form a voltage control section that controls the voltage obtained at the collector of the transistor 13, and the transistor 36 controls the emitter-collector path current of the transistor 13. transistor 13
A current control section is formed to limit the emitter-collector path current of the transistor. And the other parts are
The circuit is constructed similarly to the circuit shown in FIG.

Under such a configuration, the input voltage Vi is set to a predetermined value, for example,
If the voltage exceeds 4.7V, the emitter potential of the transistor 32 turned on by applying a base bias voltage through the series connection of the resistors 30 and 31, that is, the base potential of the transistor 34 turns the transistor 34 off. It is assumed that the Therefore, transistor 34 is turned off, and accordingly transistor 36 is also turned off, resulting in a circuit substantially equivalent to that shown in FIG. 2. In such a state, if the output voltage vO rises or falls due to fluctuations in the input voltage Vi or fluctuations in the load connected to the output terminal 12, the same operation as in the circuit shown in FIG. 2 described above occurs. As a result, the emitter-collector path current of the PNP resistor 15 forming the stabilization control section decreases or increases with respect to the rise or fall of the output voltage ■0, and therefore the resistor 30
The voltage across the series connection of transistors 13 and 31 decreases or increases, and the emitter-base voltage of transistor 13 decreases or increases. As a result, the emitter-collector impedance of the transistor 13 increases or decreases, causing the output voltage Vo to drop or rise.In the end, the rise or fall of the output voltage Vo is suppressed. An output voltage 0 stabilized at .2V is obtained. In this way, when the input voltage Vi exceeds a predetermined value, for example, 4.7V, the emitter-base voltage of the transistor 13 becomes a predetermined value, for example, 0.5 V or more, and the transistor 13 There is no possibility of operating in the saturated operating region.

On the other hand, when the input voltage Vi decreases below a predetermined value, for example, below 4°7V, the emitter potential of the transistor 32 and, therefore, the base potential of the transistor 34 decreases.
4 to the value that turns it on. As a result, the transistor 34 is turned on, and the current 11 flows from the collector of the transistor 13 through the emitter-collector path of the transistor 34 and the resistor 35, and the voltage obtained at the collector of the transistor 13, that is, the output voltage 0
is lowered, so that the power-to-base voltage of the transistor 13 is maintained at a predetermined value, for example, 0.5μ or more. At this time, due to the decrease in the output voltage 0, the voltage vO'' obtained at the connection point between the resistor 16 and the resistor 17 also decreases.
0 and NPN transistor 28 causes the emitter-collector path current of transistor 15 to increase, thereby supplementing the base current of transistor 13 and increasing the emitter-collector path current of transistor 13.

When the input voltage Vi further decreases, the current 11 flowing from the collector of the transistor 13 through the emitter-collector path of the transistor 34 and the resistor 35 increases, and the voltage across the resistor 35 increases accordingly, causing the voltage across the resistor 35 to increase.
The base potential of increases to a value that turns transistor 36 on.

When transistor 36 is turned on, transistor 2
A part of the current flowing from the collector of transistor 5 to the collector-emitter path of transistor 22 is shunted as current 12 to the collector-emitter path of transistor 36, so that the emitter-collector path current of transistor 25 increases. . Since the emitter-collector path currents of transistors 25 and 26 are made equal by current mirror operation, the emitter-collector path current of transistor 26 increases as the collector-emitter path current of transistor 25 increases. Therefore, the base current of transistor 28 increases. As a result, the collector-emitter path current of transistor 28 increases, the base current of transistor 15 decreases, the emitter-collector path current of transistor 15 decreases, and the base current of transistor 13 decreases.

As a result, an increase in the emitter-collector path current of the transistor 13 is suppressed and limited to a predetermined value or less.

In this way, if the input voltage Vi is below a predetermined value, for example,
When the voltage drops below 4.7V, the transistor 1
3, the voltage between the emitter and the collector is a predetermined value, for example, 0.
5■ or more, therefore, the transistor 13 is not allowed to operate in the saturation operation region, and
Due to the operation of the transistor 36 forming the current limiter,
The emitter-collector path current of transistor 13 is limited to prevent it from becoming excessive.

(Effects of the Invention) As is clear from the above description, the stable overvoltage supply circuit according to the present invention has a configuration in which a lateral transistor is used as a control transistor connected between an input terminal and an output terminal. In addition, it is possible to obtain an output voltage at the output terminal and supply it to the load, which is stabilized against fluctuations in the input voltage supplied to the input terminal or fluctuations in the load connected to the output terminal. Even when the voltage decreases below a predetermined value, the lateral transistor used as a control transistor can be prevented from operating in the saturation operation region, and the emitter-collector path current of the lateral transistor can be prevented from becoming excessive. can be prevented. Therefore, when an integrated circuit device is used that includes a lateral transistor used as a control transistor, the semiconductor substrate of the integrated circuit device is relatively affected by the effects of parasitic transistors that will be formed in association with the lateral transistor. A state in which a large current flows does not occur, and it is possible to avoid a situation in which the reliability of the integrated circuit element is degraded or a situation in which a large burden is placed on the voltage source connected to the input terminal.

[Brief explanation of drawings]

Fig. 1 is a circuit connection diagram showing an example of a stable overvoltage supply circuit according to the present invention, and Fig. 2 is a circuit connection diagram showing a series type stable overvoltage supply circuit in which a conventional lateral/PNP) transistor is used as a control transistor. be. In the figure, 11 is an input terminal, 12 is an output terminal, 13 is a lateral PNP l-transistor, 19 is a constant voltage source, 20 is a comparison circuit section, 15 and 34 are PNP transistors, 28
and 36 are NPN l-transistors. Figure 1

Claims (1)

[Claims] A lateral transistor with an emitter-collector path connected between an input terminal and an output terminal, an output voltage obtained at the output terminal or a voltage obtained according to the output voltage, and a reference voltage. a stabilization control section that stabilizes the output voltage by controlling the emitter-base voltage of the lateral transistor according to the output of the comparison section; and the emitter-collector of the lateral transistor. a voltage control section that operates according to the voltage between the emitter and the collector and controls the voltage obtained at the terminal connected to the output terminal of the lateral transistor in order to maintain the emitter-collector voltage above a predetermined value; A stable overvoltage supply circuit comprising: a current control section that operates in response to an emitter-collector path current and performs control to maintain the emitter-collector path current below a predetermined value.