JPH0730339A - Monolithic power amplifying integrated circuit - Google Patents

Abstract

PURPOSE:To provide a monothilic power amplifying integrated circuit in which a power supply voltage ad useless current consumption can be saved. CONSTITUTION:When an input signal voltage is turned to a high level, and an emitter grounded npn transistor 21 of a mirror reference stage 20 is turned on, currents flow from a reference current part 22 of a mirror circuit constituted of a lateral emitter grounded pnp transistor through a corrector resistance 23. Then, the precise constant currents are supplied to a lateral emitter grounded pnp transistor 32 constituting the mirror current part of the mirror circuit and the load elements of a complementary circuit stage 30 in a non-saturating mode. Thus, although the lateral emitter grounded pnp transistor 32 is used, the load elements of the complementary circuit stage 30 are constituted of the mirror current part of the mirror circuit, so that current consumption reduction and a low power supply voltage operation can be realized.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to monolithic power amplifier integrated circuits, and more particularly to power amplifier circuits of the monolithic bipolar complementary transistor circuit type.

[0002]

2. Description of the Related Art JP-A-58-38371 discloses a pn
A monolithic bipolar complementary integrated circuit using a pnp mirror circuit composed of p transistors is disclosed. That is, FIG. 1 discloses that the reference current stage of the pnp mirror circuit is used as the load element of the constant current source composed of the npn transistor, so that the mirror current stage serves as the high side constant current source. . This kind of application of mirror circuits is well known.

FIG. 4 shows an example of a conventional monolithic power amplifier integrated circuit. This circuit is a high-power bipolar transistor power amplifier circuit for driving an ignition device of an internal combustion engine, in which 100 is a grounded-emitter npn transistor and a collector resistor (in this specification, it means a load resistor connected to the collector side). It is a first-stage inverting circuit stage consisting of and. Two
Reference numeral 00 denotes a next-stage inverting circuit stage which is composed of a grounded-emitter npn transistor for inverting the output voltage of the first-stage inverting circuit stage 100 and a collector resistor. 300 is the first inverting circuit stage 100
Driver element 301 composed of a grounded-emitter npn transistor for inverting the output voltage of
And a load element 302 including an npn emitter follower transistor supplied with a base current from the output terminal of the. Reference numeral 400 denotes a driver element 401 formed of a grounded-emitter npn transistor that inverts the output voltage of the first stage inversion circuit stage 100, and a load element 402 formed of an npn emitter follower transistor supplied with a base current from the output terminal of the complementary circuit stage 300. It is a complementary circuit stage having. Reference numeral 500 designates a Darlington connection grounded emitter npn transistor 501 as a driver element and an ignition coil 50.
2 is a power amplification circuit stage using 2 as a load element.

Since the input signal voltages of the emitter follower transistors 302 and 402 of the complementary circuit stages 300 and 400 and those of the grounded-emitter transistors 301 and 401 have opposite phases to each other, power consumption is reduced, operation speed is increased, and heat generation is reduced. Can be achieved. FIG. 5 shows another example of a conventional monolithic power amplifier integrated circuit. This circuit replaces the emitter follower transistor of the circuit 300 of FIG. 4 with a grounded-emitter pnp transistor 303, and at the same time, makes the input of the next inverting circuit stage 200 the same as the first inverting circuit stage 100. When the transistor 303 is saturated, the power supply voltage can be dropped by the ON voltage V _F of the transistor 302.

[0005]

However, in a high power switching circuit as shown in FIG. 4, multistage emitter follower circuits 300, 400 and 500 are required for current amplification, and as a result, the emitter / follower circuits of each stage are It is necessary to increase the power supply voltage by accumulating the on-voltage V _F between the bases.

Further, in order to reduce the on-current of the transistor 302 of the circuit 300 and save the power consumption, it is necessary to provide the collector resistor R11, and as a result, the power supply voltage + V is increased by the voltage drop of the collector resistor R11. It will increase. Similarly, in order to reduce the on-current of the transistor 201 of the circuit 200 and save power consumption, it is necessary to increase the collector resistance R10. As a result, the collector resistance R10 of the base current when the transistor 302 is on is increased. The power supply voltage + V increases by the amount of the voltage drop.

On the other hand, the grounded emitter pn as shown in FIG.
Integrating the p-transistor 303 into a monolithic npn-transistor power amplifier integrated circuit requires it to have a lateral transistor structure. Here, the circuit 10
The low level is output from 0 and 200, and the transistor 3
Consider the case where 01 is turned off, the transistor 303 is turned on, and the base current of the emitter follower transistor 402 is supplied from the transistor 303. Transistor 301
Is off, the collector current of the transistor 303 only supplies the base current of the emitter follower transistor 402, and the lateral pnp transistor 303
Since the current amplification factor of 1 varies, the circuit is designed with a considerable collector current margin. For this reason, the transistor 303 has a sufficient current supply capacity and is in a saturated operation.

However, as described above, this pnp
Since the transistor 303 has a lateral structure, when the potential of the collector region that surrounds the side surface of the emitter region becomes almost the same as the emitter potential due to the saturation operation, the collector depletion layer shrinks and is injected from the emitter region to the base region to amplify. The generated holes are not absorbed by the collector region, and the substrate absorption current absorbed by the p-type substrate increases. In particular, this lateral pnp transistor / vertical np
In the n-transistor integrated circuit structure, it is necessary to give a minimum potential to the p-type substrate for reverse bias, and as a result, the depletion layer formed at the junction between the base region of the pnp transistor 303 and the p-type substrate is the base. The transistor 30 is largely projected into the region, and the transistor 30 is eventually absorbed by the substrate absorption current.
The collector current amplification factor of No. 3 decreases.

That is, the collector region of the lateral emitter grounded pnp transistor whose emitter region has almost the same potential due to the saturation operation constitutes a parasitic transistor having the P-type substrate as the collector region, and as a result, the collector region through the base region. Holes are injected into the p-type substrate, and this action also increases the substrate absorption current.

Therefore, the voltage drop of the emitter resistance Re is further increased by the amount of the substrate absorption current, and the power supply voltage + V is increased accordingly. FIG. 3 shows experimental results showing the relationship between the power supply voltage + V and the substrate absorption current (hereinafter, also referred to as leak current) Il in the circuit configuration of FIG.
After all, the emitter follower type circuit 300 of FIG. 4 is replaced with the lateral pnp transistor type circuit 300 of FIG. 7 having a complicated structure.
Even if it is replaced with, the power supply voltage drop effect cannot be expected.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a monolithic power amplifier integrated circuit capable of operating at a low power supply voltage and reducing unnecessary current consumption.

[0012]

SUMMARY OF THE INVENTION A monolithic power amplifier integrated circuit according to the present invention includes a reference current portion of a mirror circuit including a grounded emitter pnp transistor having a lateral transistor structure, a load element including a collector resistance of the transistor, and an input signal. Grounded emitter for inverting voltage n
a mirror reference stage having a driver element composed of a pn transistor, an inverting circuit stage inverting an input signal voltage, a driver element composed of a grounded-emitter npn transistor to which a base current is supplied from an output terminal of the inverting circuit stage,
A complementary circuit stage having a load element composed of a mirror current part of the mirror circuit; and a power amplifier circuit stage having a grounded-emitter npn transistor or an emitter follower npn transistor driven and controlled by the output potential of the complementary circuit stage. It is characterized by that.

[0013]

When the input signal voltage becomes high level and the grounded-emitter npn transistor of the mirror reference stage is turned on, the grounded-emitter npn transistor is connected from the reference current portion of the mirror circuit composed of the lateral emitter-grounded pnp transistor through the collector resistor. The current is absorbed by.

As a result, the base potential of the lateral emitter grounded pnp transistor (reference current portion) is lowered due to the voltage drop of the collector resistance. Power supply voltage (emitter potential of lateral emitter grounded pnp transistor) + V
If the collector resistance is Rc and the on-voltage of the lateral emitter grounded pnp transistor is V _F , the collector current ic is approximately (+ V−V _F ) / Rc, which can be determined precisely, and the mirror current of the mirror circuit can be further determined. Some transistors can be driven in a non-saturated mode.

Therefore, the mirror current portion of the mirror circuit constitutes a load element of the complementary circuit stage, and the inverted input signal voltage inverted by the inversion circuit stage is applied to the grounded-emitter npn transistor which constitutes the driver element of the complementary circuit stage. When applied, the following operations are possible. First, the case where the input signal voltage is at a high level will be described.

In this case, the driver element of the complementary circuit stage is turned off, and the collector current value of the mirror current part of the mirror circuit becomes a predetermined value without installing a resistor for limiting the emitter current on the emitter side. Precisely retained. Therefore,
The mirror current of the mirror circuit can be set to a current required for the power amplification circuit stage, and the mirror circuit is driven in the non-saturation mode. Therefore, the potential of the collector region adjacent to the side surface of the emitter region of the lateral emitter grounded pnp transistor becomes low, so that the depletion layer of the pn junction at the boundary between the collector region and the base region extends to the base region side and extends from the emitter region. The holes injected and amplified in the base region are well absorbed.

As a result of these, although the lateral emitter grounded pnp transistor is used, the load element of the complementary circuit stage is constituted by the mirror current portion of the mirror circuit, so that wasteful current consumption can be prevented. Furthermore,
Since the emitter resistance (the resistance connected to the emitter side) of the load element (mirror current section) of the complementary circuit stage can be omitted, the voltage drop caused by the collector current and the substrate absorption current of the mirror current section by this emitter resistance is omitted. be able to.

Next, the case where the input signal voltage is low level will be described. In this case, the grounded-emitter npn transistor of the mirror reference stage to which the input signal voltage is applied is turned off, the lateral emitter-grounded pnp transistor forming the reference current portion of the mirror reference stage is turned off, and therefore the mirror of the mirror circuit is mirrored. The lateral emitter grounded pnp transistor forming the current portion, that is, the load element in the complementary circuit stage is turned off. On the other hand, the grounded-emitter npn transistor (driver element) of the complementary circuit stage is turned on by the input of the high level voltage from the inverting circuit stage, the driver element and the load element of the complementary circuit stage perform complementary operation, and DC power is consumed. Can be effectively prevented.

As a result, according to the circuit of the present invention, the power consumption can be reduced, the circuit operation can be speeded up, and the power supply voltage can be reduced.

[0020]

(Embodiment 1) An embodiment of a monolithic power amplifier integrated circuit of the present invention will be described with reference to FIG. This circuit is a drive circuit for an igniter for an internal combustion engine ignition device, and includes an inverting circuit stage 10, a mirror reference stage 20, a complementary circuit stage 30, a preamplification stage 40, and an output amplification stage 50. 40 and the output amplification stage 50 constitute the power amplification circuit stage referred to in the present invention.

The inverting circuit stage 10 uses the grounded-emitter npn transistor 11 to which the input signal voltage Vi is fed through the base current limiting resistor 13 as a driver element, and its collector resistor 12 as a load element. The mirror reference stage 20 is
A grounded emitter npn transistor 21 fed through a base current limiting resistor 23 is used as a driver element, and a lateral emitter grounded pnp composed of a reference current portion of a mirror circuit.
The transistor 22 and its collector resistance 23 are used as load elements.

In the complementary circuit stage 30, the grounded emitter npn transistor 31 to which the output voltage of the inverting circuit stage 10 is applied to the base through the base current limiting resistor 33 is used as a driver element, and the lateral emitter grounded which constitutes the mirror current portion of the mirror circuit. The pnp transistor 32 is used as a load element. The preamplification stage 40 uses, as a driver element, a grounded-emitter npn transistor 41 to which the output voltage of the inverting circuit stage 10 is applied to the base through a base current limiting resistor 43.
An emitter follower npn transistor 42 to which the output voltage of the complementary circuit stage 30 is applied to the base is used as a load element.

The output amplification stage 50 uses the Darlington npn transistor 51, to which the output voltage of the preamplification stage 40 is applied to the base through the base current limiting resistor 53, as a driver element and the ignition coil 52 as a load element. The power supply voltage + V is applied to the high end of each load element, and the low end of each driver element is grounded. The operation of this circuit will be described below.

First, the case where the input signal voltage Vi is at the high level will be described. In this case, the transistor 11,
21 is turned on, the output voltage Va of the inverting circuit stage 10 becomes low level (almost ground potential), and the transistors 31, 41
Turns off. When the transistor 21 is turned on, the lateral emitter grounded pnp forming the reference current portion of the mirror circuit is formed.
The current i flowing through the transistor 22 is the collector resistance 23
The resistance value of Rc is Rc, and the on-voltage (between emitter and base) of the lateral emitter grounded pnp transistor 22 is V _F
If the collector current ic is substantially _{(+ V-V F) /} Rc
Is set precisely. Furthermore, the lateral emitter ground pn
The collector potential of p-transistor 22 is equal to the base potential, and transistor 22 always operates in non-saturation mode.

As a result, the collector current ic 'of the lateral emitter grounded pnp transistor 32, which is the mirror current portion of the mirror circuit, becomes 4 × ic here, and the emitter resistance for current limitation is provided between the emitter of the transistor 32 and the power supply terminal. It can be precisely determined without adding.
By omitting the emitter resistance, the voltage drop can be removed, and low power supply voltage operation is realized.

Further, the collector potential of the lateral emitter grounded pnp transistor 32, which is the mirror current portion of the mirror circuit, becomes sufficiently low to enter the non-saturation operation mode. Therefore, the lateral emitter grounded pnp transistor 3
The second collector depletion layer overhangs to the base region side and satisfactorily absorbs the amplified holes injected from the emitter region to the base region. Therefore, the collector efficiency (collector current amplification factor) of the lateral emitter grounded pnp transistor 32 is significantly improved, and power consumption is reduced. Since the emitter resistance of the transistor 32 is omitted as described above, it is not necessary to increase the power supply voltage + V in consideration of the voltage drop due to the emitter resistance due to the substrate absorption current.

Therefore, the collector current of the transistor 32 is the emitter follower transistor 4 of the preamplification stage 40.
The current is amplified by 2 and supplied to the output amplification stage 50, and the transistor 51 of the output amplification stage 50 can supply a large current to the coil 52. Next, the case where the input signal voltage Vi is at the low level will be described. In this case, transistor 1
1, 21 are turned off, the output voltage Va of the inverting circuit stage 10 becomes high level (+ V), and the transistors 31, 41 are turned on.

When the transistor 21 is turned off, the lateral emitter ground pnp forming the reference current portion of the mirror circuit.
The transistor 22 turns off, and the lateral emitter common pnp transistor 32, which is the mirror current part of the mirror circuit, also turns off. As a result, the emitter follower transistor 42
Turns off and the transistor 51 turns off.

As described above, in this embodiment, the grounded-emitter npn transistor 21 to which the input signal current is fed, the collector resistor 23, and the reference current portion 2 of the mirror circuit are provided.
2 constitutes a mirror reference stage 20, and a grounded-emitter npn transistor 31 to which a current having a phase opposite to that of the input signal current is fed and a mirror current portion 32 of the mirror circuit.
0, and the output voltage or output current of the complementary circuit stage 30 is used to drive the grounded-emitter npn transistor power amplification stage.

Therefore, as described above, the DC current consumption of the complementary circuit stage 30 is prevented, the current absorption of the p-type substrate is significantly reduced, and it is accurate regardless of the variation in the current amplification factor of the lateral emitter-grounded pnp transistor 32. It is possible to output various output currents, and it is possible to achieve an excellent effect that a low power supply voltage operation can be performed. As a result, according to the circuit of the present embodiment, it is possible to reduce power consumption, speed up the circuit operation, and realize a low power supply voltage operation.

The dotted line in FIG. 3 shows the measurement result of the substrate absorption current IL in the circuit of this embodiment. It can be seen that the substrate absorption current can be significantly reduced as compared with the conventional example of FIG. (Embodiment 2) FIG. 2 shows another embodiment. This example
The preamplification stage 40 of FIG. 1 is omitted, and the output voltage of the complementary circuit stage 30 is directly driven by the output amplification stage 50. The operation and effect are the same as those of the first embodiment.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a monolithic power amplification integrated circuit of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of FIG.

FIG. 3 is a characteristic diagram showing a relationship between a substrate absorption current (leakage) current and a power supply voltage + V in the circuit of FIG.

FIG. 4 is a circuit diagram showing an example of a conventional monolithic power amplification integrated circuit.

FIG. 5 is a circuit diagram showing an example of a conventional monolithic power amplification integrated circuit.

[Explanation of symbols]

Reference numeral 10 is an inverting circuit stage, 20 is a mirror reference stage, 21 is a grounded emitter npn transistor which forms a driver element of the mirror reference stage, 22 is a lateral emitter grounded pnp transistor which is a reference current portion of the mirror reference stage, and 23 is a collector of the transistor 22. A resistor, 30 is a complementary circuit stage, 31 is a grounded-emitter npn transistor of the complementary circuit stage, 32 is a load element of the complementary circuit stage 30, and a lateral emitter grounded pnp transistor that forms a mirror current portion of the mirror circuit, and 40 is a preamplification stage ( The power amplifier circuit stage according to the present invention) and 50 are output amplifier stages (power amplifier circuit stage according to the present invention).

Claims (1)

[Claims] 1. A reference current part of a mirror circuit composed of a grounded emitter pnp transistor having a lateral transistor structure and a load element composed of a collector resistance of the transistor, and a driver element composed of a grounded emitter npn transistor which inverts an input signal voltage. A mirror reference stage having the same, an inverting circuit stage for inverting the input signal voltage, a driver element composed of a grounded-emitter npn transistor to which a base current is fed from an output terminal of the inverting circuit stage, and a mirror current section of the mirror circuit. A complementary circuit stage having a load element, and a grounded-emitter npn transistor or emitter follower npn driven and controlled by the output terminal potential of the complementary circuit stage
A monolithic power amplifier integrated circuit comprising: a power amplifier circuit stage having a transistor;