JPH0818425A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To provide a push-pull type output circuit for drive-controlling a load requiring a relatively large driving current at a high speed. CONSTITUTION:Two npn transistorsQ1 and Q2 are serially connected and a pMOS is connected to the connection point as the load. A Vcc1 is applied to the collector of the transistorQ1 and the emitter of the transistorQ2 is connected to ground GND. The npn transistorQ11 is provided as an emitter-follower by being connected to the base of the transistorQ1 and the npn transistorQ12 is provided by being connected to the base of the transistorQ2 and performing Darlington connection. When control signals for alternately turning the transistorsQ11 and Q12 on and off are inputted, a base current is supplied to the transistorsQ1 and Q2 respectively when the transistorsQ11 and Q12 are turned to an ON state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-pull type output semiconductor integrated circuit having an improved output response.

[0002]

2. Description of the Related Art As one of circuits for driving and controlling a load,
Push-pull output configurations are used in various forms. The push-pull type output circuit connects two equivalent circuits (for example, switching elements such as transistors) in series, and takes out the connection point as an output signal.
In addition, the operation controls the output voltage (or output current) by inputting switching control signals of opposite phases to each of the above circuits and turning one of them on and the other off. The push-pull output circuit uses the output as a gate signal to control ON / OFF of the MOS transistor and control the rotation of the motor.

FIG. 4 is a circuit diagram showing an example of a conventional general push-pull type output circuit and its drive circuit. In the figure, npn-type transistors Q1 and n
The pn-type transistor Q2 constitutes a main part of the push-pull type output circuit. The emitter of the transistor Q1 and the collector of the transistor Q2 are connected to each other, and the output V _OUT at this connection point is used as a gate signal of a MOS transistor, for example. The voltage _Vcc1 is applied to the collector of the transistor Q1 and the emitter of the transistor Q2 is connected to the ground GND. A constant current source I ₁ is connected to the base of the transistor Q1 and a constant current source I ₂ is connected to the base of the transistor Q2. Furthermore, in order to drive and control the push-pull type output circuit of the above configuration, transistors Q3~Q6 and a constant current source I ₃ I ₄ is provided.

Next, the operation of the above circuit will be described. First,
As the input signal V _in, when a voltage is applied (ON signal) that turns on the transistors Q3, the transistor Q4
And Q5 is turned off. And the transistor Q
When transistor 4 is turned off, transistor Q6 is turned on. As a result, the current of the constant current source I ₁ flows to the ground GND via the transistor Q6, so that the transistor Q1 is turned off. On the other hand, the current of the constant current source I ₂ becomes the base current of the transistor Q2, and the transistor Q2 is turned on. Therefore, the output V _OUT is G
The voltage value is close to the ND level.

[0005] As the input signal V _in, when a voltage is applied (OFF signal), such as to turn off the transistors Q3, the state of the transistor Q3~Q6 becomes a opposite state as entering an ON signal as the input signal V _in, The transistor Q1 is turned on and the transistor Q2 is turned off. Therefore, the output V _OUT has a voltage value close to V _cc1 .

As described above, by switching the input signal V _in , the transistors Q1 and Q2 are controlled to be turned on / off alternately, and the output V _OUT is controlled. Then, using this output V _OUT , for example, ON / OFF control of the MOS transistor is performed.

[0007]

By the way, the above output V
_When driving a load using _OUT , high-speed driving may be required. For example, if the load is a MOS transistor and the output V _OUT is its gate signal, MO
There is a demand for high-speed switching of the S transistor. In this case, it is essential that the transistors Q1 and Q2 can be switched at high speed.

On the other hand, there are cases where a relatively large current is required to drive the load. In this case, it is necessary to increase the capacitance of the transistors Q1 and Q2, and especially the emitter junction area becomes large. Here, in order to turn on the transistor Q1 or Q2, it is necessary to raise the base voltage to a predetermined value (the degree to which a forward current flows in the pn junction between the base and the emitter). If the junction area is large, it is necessary to supply sufficient charges to reach the predetermined voltage. Therefore, if the current supplied by the constant current source I ₁ or I ₂ is small, the turn-on time of the transistor Q1 or Q2 becomes long, and as a result, the load cannot be driven at high speed. Further, if the load cannot be driven in a short time, heat generation of the transistor Q1 or Q2 itself becomes a problem.

To solve this problem, a constant current source I
It is conceivable that the current supplied by ₁ or I ₂ is large, but in that case, the scale of the constant current sources must be increased, and the overall configuration combining the push-pull type output circuit and its drive circuit is large. So, by design,
Inconvenience may occur.

As described above, it has been difficult to construct a push-pull type output circuit for driving and controlling a load requiring a relatively large drive current at a high speed on a small scale.
The present invention solves the above problems, and an object of the present invention is to realize a push-pull output circuit for driving and controlling a load requiring a relatively large drive current at a high speed with a small-scale configuration.

[0011]

In a semiconductor integrated circuit of the present invention, a first transistor and a second transistor are connected in series, and control signals of opposite phases are provided to respective bases of the first and second transistors. Enter them first and second
It is assumed that the load connected to the connection point of the transistor is driven.

According to another aspect of the semiconductor integrated circuit of the present invention, a current supply means for supplying a current is connected to the base of at least one of the first and second transistors. The current supply means is, for example, a transistor or a resistor.

A semiconductor integrated circuit according to a second aspect of the invention is based on the configuration of the first aspect, and when the control signal turns on the first or second transistor, the current supply means turns on. Supply current to the base of the transistor that goes into the state

A semiconductor integrated circuit according to a third aspect is based on the configuration of the first aspect, and the first and second transistors are npn type transistors. Then, the emitter of the first transistor and the collector of the second transistor are connected. A first potential is set to the collector of the first transistor, and a second potential lower than the first potential is set to the emitter of the second transistor.

A semiconductor integrated circuit according to a fourth aspect is based on the configuration of the third aspect, and the current supply means is configured by an npn-type third transistor. Then, the emitter of the third transistor is connected to the base of the first or second transistor, and the collector of the third transistor is connected to the collector of the first or second transistor. Also, one of the control signals is input to the base of the third transistor.

A semiconductor integrated circuit according to a fifth aspect of the invention is based on the structure of the fourth aspect, and when the third transistor is connected to the first transistor, both ends of a plurality of resistors connected in series are respectively connected. The first potential and the second potential are set, and one of the connection points of the plurality of resistors is connected to the base of the third transistor.

A semiconductor integrated circuit according to a sixth aspect is based on the configuration of the first aspect, and the current supply means is an emitter follower. A semiconductor integrated circuit according to a seventh aspect is premised on a configuration in which one collector and the other emitter of two Darlington connection circuits are connected. By inputting control signals of opposite phases to the respective bases of the two Darlington connection circuits, one of the two Darlington connection circuits is turned on and the other is turned off, and the two Darlington connection circuits are connected to each other. Drives the connected load.

[0018]

When the control signal is input to the bases of the first and second transistors, when one transistor is turned on and the other transistor is turned off, a current is supplied to the base of the transistor to be turned on. Since the means supplies the base current, its turn-on time is short. Therefore, the response of the potential at the connection point of the first and second transistors to the control signal becomes fast, and the load connected to the connection point can be driven at high speed.

The first and second transistors are connected to np
When configured with an n-type transistor, the npn-type transistor has a smaller emitter junction area than a pnp-type transistor and can be turned on with a small current, so the turn-on time of the transistor is shortened.

If the current supply means is composed of a third transistor, and its drive control is performed by the control signal, when the first or second transistor is turned on,
Sufficient current can be supplied to the base of the transistor to be turned on through the third transistor, and the turn-on time of the first or second transistor is shortened. When the third transistor is connected to the first or second transistor as a Darlington connection or an emitter follower, the current amplified by the third transistor is the base of the first or second transistor. Supplied as current.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining the principle of the semiconductor integrated circuit of the present invention. In the figure, a transistor 1 and a transistor 2 are connected in series. Control signals having opposite phases are input to the bases of the transistors 1 and 2, respectively. This control signal is a signal for controlling on / off of each of the transistors 1 and 2, and turns one transistor on and the other transistor off. Then, turning on these transistors 1 and 2
Depending on the off state, the potential V _out (or current) at the connection point of the transistors 1 and 2 is controlled, and drive control of the load 3 connected thereto is performed.

Current supply circuits 4 and 5 are connected to the bases of the transistors 1 and 2, respectively. The current supply circuits 4 and 5 are composed of, for example, transistors or resistors. Therefore, even if such a circuit is added, the scale of the circuit is hardly changed. The current supply circuits 4 and 5 are controlled by the above-mentioned control signal, and when the transistor 1 is turned on, the current supply circuits 4 and 5 are
Supplies the base current to the transistor 1 and turns on the transistor 2, the current supply circuit 5 supplies the base current to the transistor 2.

When the drive current of the load 3 is relatively large,
Since the capacitance of the transistors 1 and 2 becomes large, a large amount of the base voltage is required when the base voltage is changed to a predetermined value (a forward current flows to the pn junction between the base and the emitter) in order to turn on the transistor 1 or 2. Although it is necessary to supply the electric charge, in the configuration shown in FIG. 1, the electric current supply circuits 4 and 5 supply the electric charge.

With such a configuration, the switching speed of the transistors 1 and 2 becomes high, and the response of the output V _{out to} the control signal becomes fast. Therefore,
The load 3 can be drive-controlled at high speed.

FIG. 2 is a circuit diagram showing an embodiment of the push-pull type output circuit and its drive circuit. In the figure, the npn-type transistor Q1 and the npn-type transistor Q2 form a main part of the push-pull type output circuit. The emitter of the transistor Q1 and the collector of the transistor Q2 are connected, and a p-type MOS is connected at this connection point.
The gate of the transistor is connected. In addition, the voltage _Vcc1 (+ 13V) is applied to the collector of the transistor Q1, and the emitter of the transistor Q2 is grounded.
It is connected to ND.

The base of the transistor Q1 is a constant current source I
It is connected to the emitters of ₁ and npn type transistor Q11, and is also connected to the collector of npn type transistor Q17. The constant current source I ₁ is a current mirror circuit. The collector of the transistor Q11 is connected to the collector of the transistor Q1 and the voltage V _cc1 is applied. The base of the transistor Q11 is connected to the connection point of the resistors R1 and R2 that _divide the voltage _{Vcc1, and also} to the collector of the npn-type transistor Q18. In this way, the transistor Q11 is provided as an emitter follower, and the emitter follower is used to supply the base current to the transistor Q1.

The base of the transistor Q2 is connected to the emitter of the npn-type transistor Q12 and is also connected to the ground GND via the resistor R3. The collector of the transistor Q12 is connected to the collector of the transistor Q2. The base of the transistor Q12 is connected to the constant current source I ₁₄ , and the base of the transistor Q12 is an npn-type transistor Q12.
It is connected to 14 collectors. In this way, the transistors Q2 and Q12 are in Darlington connection, and the current amplified by the transistor Q12 is supplied as the base current to the transistor Q2.

Further, in order to drive and control the push-pull type output circuit having the above structure, transistors Q13 to Q1 are provided.
8 and constant current sources I _{13 to} I ₁₆ are provided. Each of the transistors Q13 to Q18 is an npn type, has a relatively small capacitance, and is a device capable of high-speed switching with a small current. The constant current sources I _{13 to} I ₁₆ are current mirror circuits and generate current from V _CC2 (+5 V).

Next, the operation of the above circuit will be described. When a voltage (ON signal) that turns on the transistor Q13 is applied as the input signal V _in , the current generated by the constant current source I ₁₃ flows to the ground GND through the transistor Q13, and thus the current flows to the transistors Q14, Q15, and Q16. Base current is no longer supplied to these transistors Q
14, Q15 and Q16 are turned off. And
When the transistor Q14 is turned off, the constant current source I ₁₄
Is a base current of the transistor Q12, and the transistor Q12 is turned on. The current flowing through the transistor Q12 is the transistor Q
2 becomes the base current, the base potential of the transistor Q2 rises, and the transistor Q2 turns on.

In this way, when the ON signal is input as the input signal V _in , the first-stage transistor Q12 of the Darlington connection circuit is turned on, and the transistor Q1 is turned on.
Since the current amplified by 2 is transferred to the base of the transistor Q2, the transistor Q2 can be turned on in a short time even if the capacitance of the transistor Q2 is large.

On the other hand, when the transistor Q15 and Q16 are turned off, the current generated by the constant current source I ₁₅ and I _16, respectively become the base current of the transistor Q18 and Q17, which transistors Q18 and Q1
7 is turned on. When the transistor Q17 is turned on, the current generated by the constant current source I ₁ is generated by the transistor Q17.
Since it flows to GND via 17
No current is supplied to the base of 1. When the transistor Q18 is turned on, the current I flowing through the resistor R1
_{Since R1} flows to the ground GND through the transistor Q18, the base current is not supplied to the transistor Q11,
The transistor Q11 is turned off. Therefore, the transistor Q1 is turned off.

In this way, when the transistor Q1 is turned off and the transistor Q2 is turned on, the push
The output V _out of the pull-type output circuit has a potential close to the GND level. In reality, the potential of the output V _out is about 1 V because of the forward voltage due to the pn junction of the transistor. When the p-type MOS transistor is driven by this output V _out , the p-type MOS transistor is turned on. At this time, since the turn-on operation of the transistor Q2 is fast, switching of the p-type MOS transistor is fast.

When a voltage (OFF signal) for turning off the transistor Q13 is applied as the input signal V _in , the transistors Q14, Q15 and Q16 are turned on. When transistor Q14 is turned on, the current generated by the constant current source I ₁₄ is no longer supplied to transistor Q12, transistor Q12 is turned off. Therefore, the transistor Q2 is turned off.

On the other hand, when the transistors Q15 and Q16 are turned on by the input signal V _in , the currents generated by the constant current sources I ₁₅ and I ₁₆ flow to the ground GND via the transistors Q15 and Q16, respectively. , The transistors Q18 and Q17 are turned off. When the transistor Q17 is turned off, the current generated by the constant current source I ₁ is supplied to the base of the transistor Q1. When the transistor Q18 is turned off, the current I _R1 flowing through the resistor R1 flows to the ground GND through the resistor R2 and is simultaneously supplied to the base of the transistor Q11. Here, the resistance value of the resistor R2 is large, and a part of the current I _R1 becomes the base current of the transistor Q11. Therefore, the transistor Q11 is turned on,
The current amplified by the transistor Q11 becomes the base current of the transistor Q1. And the transistor Q
1 turns on.

As described above, when the OFF signal is input as the input signal V _in , the transistor Q11 provided as the emitter follower turns on, and the current amplified by the transistor Q11 is transferred to the base of the transistor Q1. In the emitter follower, the potential of the emitter, which is the output terminal, follows the potential of the base, which is the input terminal, and the driving capacity is large. The value can be increased to the value, and the turn-on operation of the transistor Q1 can be performed at high speed.

Now, the turn-on operation of the transistor Q1 will be described in detail. When the transistor Q1 is off, the transistor Q2 is on, so the emitter of the transistor Q1 is at a low potential (about 1 V). By the way, the resistance ratio of the resistors R1 and R2 is
The voltage drop due to 1 is about 0.2 to 0.3V. Therefore, when the input signal V _in is switched from the ON signal to the OFF signal, that is, the transistor Q
When 17 and Q18 are turned off, the constant current source I ₁
In addition to the current generated by, the current flowing through the transistor Q11 also becomes the base current of the transistor Q1.
The base potential of the transistor Q1 rises in a short time.

As the base potential rises, the transistor Q
Although the output V _out rises after 1 is turned on, the range in which the current flowing through the transistor Q11 contributes to the rise of the output V _out is up to about V _out = V _cc1 −1.5V. After that, the current generated by the constant current source I ₁ flows into the base of the transistor Q1, so that the output V _out rises to V _out = V _{cc1 −0.6V} .

As described above, since it is possible to speed up the turn-on operation of the transistor Q1 and surely increase the output V _out to the vicinity of V _cc1 , when the p-type MOS transistor is driven by this output V _out , p The type MOS transistor can be reliably turned off at high speed.

In the above embodiment, the push side (transistor Q1) has the emitter follower configuration and the pull side (transistor Q2) has the Darlington connection, but this combination is arbitrary.

Further, in the circuit configuration shown in FIG. 2, transistors Q11 and Q12 and a resistor are added as compared with FIG. 4, but the transistors Q11 and Q12 may have a small capacitance,
These elements can be easily miniaturized and do not increase the overall circuit scale.

Furthermore, since the driving of the load has become faster,
The heat generation amount in the transistors Q1 and Q2 is reduced, and the thermal design of the system is facilitated. FIG. 3 is a circuit diagram showing another embodiment of the push-pull output circuit and its drive circuit. In FIG. 3, the same symbols as those used in FIG. 2 indicate common items.

In FIG. 3, the difference from the configuration of FIG. 2 is that the transistor Q11 of FIG. 2 is replaced with a resistor R4. The operation of the push-pull type output circuit and its drive circuit is the same as the operation described with reference to FIG.
As described above, the circuit provided as a means for supplying a current to the base of the transistor Q1 (or Q2) when it is turned on is not limited to the transistor and can be replaced with another circuit.

[0043]

In the push-pull type output integrated semiconductor integrated circuit, the base current is supplied to the bases of the two transistors forming the main part of the push-pull type output circuit when the transistors are turned on. Since the circuit is connected, its switching speed becomes high, and the load connected to the push-pull output circuit becomes high speed.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the principle of a semiconductor integrated circuit of the present invention.

FIG. 2 is a circuit diagram of a push-pull output circuit and a drive circuit thereof, which is an embodiment of a semiconductor integrated circuit of the present invention.

FIG. 3 is another embodiment of the semiconductor integrated circuit of the present invention,
It is a circuit diagram of a push-pull type output circuit and its drive circuit.

FIG. 4 is a circuit diagram showing an example of a conventional push-pull type output circuit and its drive circuit.

[Explanation of symbols]

Q1, Q2, Q11-Q18 transistor R1~R4 resistance I _1, I ₁₃ ~I ₁₆ constant current source

Claims (7)

[Claims] 1. A first transistor and a second transistor are connected in series, and control signals of opposite phases are input to the bases of the first and second transistors, respectively.
And a semiconductor integrated circuit for driving a load connected to the connection point of the second transistor, wherein a current supply means for supplying a current is connected to the base of at least one of the first and second transistors. A characteristic semiconductor integrated circuit. 2. The semiconductor integrated circuit according to claim 1, wherein the current supply means supplies a current only when the control signal turns on the first or second transistor. 3. The first and second transistors are n
a pn-type transistor, the series connection is configured by connecting the emitter of the first transistor and the collector of the second transistor, and setting a first potential at the collector of the first transistor, Second above
2. The semiconductor integrated circuit according to claim 1, wherein a second potential lower than the first potential is set to the emitter of the transistor. 4. The current supply means is an npn-type third transistor, the emitter of the third transistor is connected to the base of the first or second transistor, and the collector of the third transistor is connected. Is connected to the collector of the first or second transistor, and the third or third transistor is connected.
4. The semiconductor integrated circuit according to claim 3, wherein one of the control signals is input to the base of the transistor. 5. When the third transistor is connected to the first transistor, the first potential and the second potential are set at both ends of a plurality of resistors connected in series, and the plurality of resistors are set. 5. The semiconductor integrated circuit according to claim 4, wherein one of the connection points of the resistance of said is connected to the base of said third transistor. 6. The semiconductor integrated circuit according to claim 1, wherein the current supply means is an emitter follower. 7. In a semiconductor integrated circuit in which one collector and the other emitter of two Darlington connection circuits are connected, by inputting control signals of opposite phases to each base of the two Darlington connection circuits, A semiconductor integrated circuit characterized in that one of the two Darlington connection circuits is turned on and the other is turned off to drive a load connected to a connection point of the two Darlington connection circuits.