JP2910512B2 - Monolithic power amplifier integrated circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monolithic power amplifier integrated circuit, and more particularly to a power amplifier circuit 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 by using a reference current stage of a pnp mirror circuit as a load element of a constant current source composed of an npn transistor, the mirror current stage is used as a higher-order constant current source. . Such applications of mirror circuits are 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, and 100 denotes a common-emitter npn transistor and a collector resistor (in the present specification, means a load resistor connected to the collector side). And a first-stage inversion circuit stage consisting of 2
Reference numeral 00 denotes a next stage inversion circuit stage including a common emitter npn transistor for inverting the output voltage of the first stage inversion circuit stage 100 and a collector resistor. 300 is a first stage inverting circuit stage 100
Driver element 301 comprising a common-emitter npn transistor for inverting the output voltage of
And a load element 302 composed of an npn emitter follower transistor supplied with a base current from the output terminal of the complementary circuit. 400 includes a driver element 401 composed of a common-emitter npn transistor for inverting the output voltage of the first inverting circuit stage 100, and a load element 402 composed 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. Reference numeral 500 denotes a Darlington connection emitter-grounded npn transistor 501 as a driver element, and an ignition coil 50.
2 is a power amplifying 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 common emitter transistors 301 and 401 have phases opposite to each other, the power consumption is reduced, the operation speed is increased, and the heat generation is reduced. Can be achieved. FIG. 5 shows another example of a conventional monolithic power amplifier integrated circuit. In this circuit, the emitter-follower transistor of the circuit 300 in FIG. 4 is replaced with a common-emitter pnp transistor 303, and the input of the next-stage inverting circuit stage 200 is the same as that of the first-stage inverting circuit stage 100. If brought into saturation operation the transistor 303, it is possible to drop the power supply voltage by the ON voltage V _F of the transistor 302.

[0005]

However, in a high-power switching circuit as shown in FIG. 4, multi-stage emitter follower circuits 300, 400, and 500 are required for current amplification. it is necessary to high voltage power supply voltage due to the accumulation of the base between the oN voltage V _F.

In order to reduce the ON current of the transistor 302 of the circuit 300 and save power consumption, it is necessary to provide a collector resistor R11. As a result, the power supply voltage + V is reduced by the voltage drop of the collector resistor R11. Will increase. Similarly, in order to reduce power consumption by reducing the on-state current of the transistor 201 of the circuit 200, it is necessary to increase the collector resistance R10. As a result, the collector resistance of the collector resistance R10 due to the base current when the transistor 302 is turned on. The power supply voltage + V increases by the voltage drop.

On the other hand, as shown in FIG.
In order to integrate the p-transistor 303 into a monolithic npn-transistor power amplifier integrated circuit, it needs to have a lateral transistor structure. Here, the circuit 10
0 and 200 output a low level, and the transistor 3
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, and 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 varies, the circuit is designed with a considerable collector current margin. For this reason, the transistor 303 has an allowance for the current supply capability and performs a saturation operation.

However, as described above, this pnp
Since the transistor 303 has a lateral structure, when the potential of the collector region surrounding the side surface of the emitter region becomes substantially the same as the emitter potential due to the above-described saturation operation, the collector depletion layer is reduced and injected from the emitter region to the base region, and the transistor 303 is amplified. 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 an n-transistor integrated circuit structure, it is necessary to apply a minimum potential to the p-type substrate for reverse bias, and as a result, a depletion layer formed at the junction between the base region of the pnp transistor 303 and the p-type substrate The transistor 30 largely extends into the region, and as a result, the transistor 30 corresponds to the substrate absorption current.
3, the collector current gain decreases.

That is, the collector region of the lateral emitter grounded pnp transistor whose emitter region has substantially the same potential due to the saturation operation constitutes a parasitic transistor having the P-type substrate as a collector 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 resistor Re further increases by the substrate absorption current, and the power supply voltage + V increases by that much. FIG. 3 shows experimental results showing the relationship between the power supply voltage + V and the substrate absorption current (hereinafter, also referred to as leakage current) Il in the circuit configuration of FIG.
As a result, the emitter follower type circuit 300 of FIG. 4 is replaced with the lateral pnp transistor type circuit 300 of FIG.
Even if it replaces with, the power supply voltage drop effect cannot be expected.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a monolithic power amplifier integrated circuit capable of operating at a low power supply voltage and reducing unnecessary current consumption.

[0012]

A monolithic power amplifier integrated circuit according to the present invention will be described with reference to FIG.
If you have a lateral transistor structure with a common emitter
pnp transistor and npn common emitter transistor
And a load element comprising a reference current section 22 of a mirror circuit composed of a common-emitter pnp transistor having a lateral transistor structure and a collector resistor 24 connected to the collector of the transistor. possess a driver element 21 consisting of an emitter grounded npn transistor for inverting the voltage Vi, the collector of the reference current 22 the
Correction of the driver element 21 through the collector resistor 24
A mirror reference stage 20 connected to Kuta, the inverting circuit stage 10 for inverting the input signal voltage Vi, consisting emitter grounded npn transistor the base current is fed from the output of the inverting circuit stage 10 driver elements 31 And la
Common emitter pnp transistor having a lateral transistor structure
A mirror current section of the mirror circuit configured by a transistor
Possess a load element formed of 32, the mirror current 32
Is connected to the collector of the driver element 31.
A complementary circuit stage 30 that is characterized by comprising a power amplifier circuit stage 40 having a common emitter npn transistor or an emitter follower npn transistor 42 is driven and controlled by the output potential of the complementary circuit stage 30.

[0013]

When the input signal voltage goes high and the common-emitter npn transistor of the mirror reference stage is turned on, the common-emitter npn transistor is passed through the collector resistor from the reference current section of the mirror circuit composed of the lateral-emitter common pnp transistor. Current is absorbed.

As a result, the base potential of the lateral emitter grounded pnp transistor (reference current section) decreases due to the voltage drop of the collector resistance. The power supply voltage (emitter potential of the pnp transistor having a common lateral emitter) is + 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. Some transistors can be driven in the unsaturated mode.

Therefore, a load element of a complementary circuit stage is constituted by the mirror current portion of the mirror circuit, and an inverted input signal voltage inverted by the inverting circuit stage is applied to a common emitter npn transistor constituting a driver element of the complementary circuit stage. If the voltage is applied, the following operation becomes possible. First, a 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 portion of the mirror circuit becomes a predetermined value without installing a resistor for limiting the emitter current on the emitter side. Precisely held. Because of this,
The mirror current of the mirror circuit can be set to a current required for the power amplification circuit stage, and 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 pnp transistor becomes low, so that the depletion layer of the pn junction at the boundary between the collector region and the base region protrudes toward the base region, and The holes injected into the base region and amplified are well absorbed.

As a result, since the load element of the complementary circuit stage is constituted by the mirror current section of the mirror circuit despite the use of the lateral emitter grounded pnp transistor, useless current consumption can be prevented. Furthermore,
Since the emitter resistance (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 of the mirror current section and the substrate absorption current can be omitted. be able to.

Next, a case where the input signal voltage is at a 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, and the laterally grounded emitter pnp transistor constituting the reference current section of the mirror reference stage is turned off. The lateral-emitter pnp transistor constituting the current section, that is, the load element in the complementary circuit stage is turned off. On the other hand, the common-emitter npn transistor (driver element) in the complementary circuit stage is turned on by the input of a high-level voltage from the inverting circuit stage, and the driver element and the load element in the complementary circuit stage perform complementary operations, consuming DC power. Can be satisfactorily prevented.

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

[0020]

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

The inverting circuit stage 10 uses a common emitter npn transistor 11 to which an input signal voltage Vi is supplied through a base current limiting resistor 13 as a driver element, and its collector resistor 12 as a load element. The mirror reference stage 20
A common-emitter npn transistor 21 fed through a base current limiting resistor 23 is used as a driver element, and a common-emitter lateral pnp comprising a reference current portion of a mirror circuit is used.
It is referred to as load element transistor 22 and its the collector resistor 2 4.

The complementary circuit stage 30 uses a common emitter npn transistor 31 to which the output voltage of the inverting circuit stage 10 is applied to the base through a base current limiting resistor 33 as a driver element, and has a common lateral emitter constituting a mirror current portion of a mirror circuit. The pnp transistor 32 is used as a load element. The preamplifier stage 40 uses a common-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 as a driver element,
The 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 amplifying stage 50 uses the Darlington npn transistor 51, to which the output voltage of the preamplifying 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 of the load elements, and the low end of each of the driver elements is grounded. Hereinafter, the operation of this circuit will be described.

First, the case where the input signal voltage Vi is at a high level will be described. In this case, the transistor 11,
21 turns on, the output voltage Va of the inverting circuit stage 10 becomes low level (substantially the ground potential), and the transistors 31 and 41
Turns off. When the transistor 21 is turned on, the lateral emitter ground pnp constituting the reference current section of the mirror circuit is turned on.
The current i flowing through the transistor 22 is
And the on-voltage (between the emitter and the base) of the lateral-emitter pnp transistor 22 as V _F
Then, the collector current ic is approximately (+ V−V _F ) / Rc
Is set precisely. Furthermore, a lateral emitter grounded pn
The collector potential of p transistor 22 is equal to the base potential, and transistor 22 always operates in the non-saturation mode.

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

Further, the collector potential of the lateral-emitter pnp transistor 32, which is the mirror current portion of the mirror circuit, becomes a sufficiently low potential, and enters the non-saturated operation mode. Therefore, the lateral emitter grounded pnp transistor 3
The collector depletion layer of 2 protrudes toward the base region, and absorbs well the holes injected from the emitter region into the base region and amplified. Therefore, the collector efficiency (collector current amplification factor) of the lateral-emitter grounded pnp transistor 32 is greatly improved, and power consumption is reduced. Further, as described above, since the emitter resistance of the transistor 32 is omitted, 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 controlled by the emitter follower transistor 4 of the preamplifier stage 40.
2, the current is amplified 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, a case where the input signal voltage Vi is at a low level will be described. In this case, transistor 1
1 and 21 are turned off, the output voltage Va of the inverting circuit stage 10 becomes high level (+ V), and the transistors 31 and 41 are turned on.

When the transistor 21 is turned off, the lateral emitter ground pnp constituting the reference current portion of the mirror circuit is turned off.
The transistor 22 is turned off, and the laterally-grounded pnp transistor 32, which is a mirror current part of the mirror circuit, is also turned off. As a result, the emitter follower transistor 42
Is turned off, and the transistor 51 is turned off.

[0029] As described above, in this embodiment, the emitter input signal current is fed grounded npn transistor 21 and the reference current section 2 of the collector resistor 2 4 and the mirror circuit
2 form a mirror reference stage 20, and a complementary circuit stage 3 includes a common emitter npn transistor 31 to which a current having a phase opposite to that of the input signal current is supplied, 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 common 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 greatly reduced, and the current can be accurately obtained regardless of the variation in the current amplification factor of the lateral-emitter pnp transistor 32. An excellent effect that a high output current can be output and a low power supply voltage operation can be performed can be obtained. As a result, according to the circuit of this embodiment, power consumption can be reduced, circuit operation can be speeded up, and low power supply voltage operation can be realized.

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 is
The preamplifier stage 40 of FIG. 1 is omitted, and the output amplifier stage 50 is directly driven by the output voltage of the complementary circuit stage 30. The operation and effect are the same as those of the first embodiment.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing another embodiment of FIG. 1;

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 amplifier integrated circuit.

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

DESCRIPTION OF THE SYMBOLS 10 is an inverting circuit stage, 20 is a mirror reference stage, 21 is a common emitter npn transistor forming a driver element of the mirror reference stage, 22 is a lateral emitter grounded pnp transistor forming a reference current portion of the mirror reference stage, 2 4 is a collector resistance of the transistor 22, 30 is a complementary circuit stage, 31 is a common emitter npn transistor of the complementary circuit stage, 32 is a lateral emitter grounded pnp transistor forming a load element of the complementary circuit stage 30 and a mirror current part of the mirror circuit, 40 Denotes a preamplifier stage (power amplifier circuit stage in the present invention), and 50 denotes an output amplifier stage (power amplifier circuit stage in the present invention).

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-94464 (JP, A) JP-A-63-294121 (JP, A) JP-A-59-99808 (JP, A) JP-A-2- 301664 (JP, A) JP-A-2-1609 (JP, A) JP-A-59-17712 (JP, A) JP-A-55-66659 (JP, A) JP-A-6-326580 (JP, A) JP-A-6-90157 (JP, A) JP-A 2-72017 (JP, U) Semiconductor Handbook Compilation Committee, “Semiconductor Handbook”, 2nd edition, Ohm Co., Ltd., November 1977, p. 419− 420 (58) Field surveyed (Int.Cl. ⁶ , DB name) H03F 1/42-1/56 H03F 3/20-3/36 H03F 3/42-3/44 H03F 3/50-3 / 52 F02P 1/00-3/12 F02P 7/00-7/10 F02P 9/00-17/00

Claims (1)

(57) [Claims] 1. An EMI having a lateral transistor structure.
Grounded pnp transistor and npn grounded emitter transistor
Monolithic power amplifier integrated circuit with transistor
And a common emitter pnp having a lateral transistor structure.
Reference current section 22 of mirror circuit composed of transistors
And a load element comprising a collector resistor 24 which is connected to the collector of said transistor, possess a driver element 21 consisting of an emitter grounded npn transistor for inverting the input signal voltage Vi, the collector of the reference current 22 before
The collector of the driver element 21 is connected through the collector resistor 24.
A mirror reference stage 20 connected to the selector, the inverting circuit stage 10 for inverting the input signal voltage Vi, consisting emitter grounded npn transistor the base current is fed from the output of the inverting circuit stage 10 driver elements 31 And an emitter having a lateral transistor structure
Possess a load element composed of a mirror current portion 32 of the mirror circuit composed of the ground pnp transistors, the mirror
The collector of the current section 32 is
A complementary circuit stage 30 connected to the emitter and a common emitter npn transistor or emitter follower n driven and controlled by an output terminal potential of the complementary circuit stage 30.
a power amplifier circuit stage 40 having a pn transistor 42. A monolithic power amplifier integrated circuit comprising: