JPH0411129B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pulse output circuit used in electronic equipment, etc., and in particular, is capable of amplifying an input pulse signal and outputting an output pulse whose polarity is inverted. This invention relates to a pulse output circuit configured as follows.

(Prior art) Figure 2 is a circuit diagram of an example of a previously proposed pulse output circuit used for pulse signal processing in various electronic devices, where 1 is an input terminal for input pulse signals, and 2 is an output terminal for output pulse signals. The output terminal 3 is an external load. In the already proposed pulse output circuit shown in FIG. 2, one end of the resistor R11 is connected to the input terminal 1, and the other end is connected to the transistor Q11.
and the base of transistor Q14, and is also connected to the anode of diode D12.

The emitter of the transistor Q11 is connected to the anode of the diode D11 and the transistor Q12.
, and the cathode of the diode D11 described above is grounded. The collector of the transistor Q12 described above is connected to the cathode of the diode D12, one end of the resistor R12, and the base of the transistor Q13, and the other end of the resistor R12 is connected to the reference voltage source Vcc. There is. Further, the emitter of the transistor Q12 described above is grounded.

Transistor Q13 and transistor Q described above
The collector of the transistor Q14 is connected to the reference voltage source Vcc, and the emitter of the transistor Q13 is connected to the collector of the transistor Q15 and the output terminal 2. The transistor Q mentioned above
The emitters of transistor Q15 are grounded, and their bases are connected to the emitter of transistor Q14 and one end of resistor R13.
The other end of 13 is grounded.

In the pulse output circuit shown in the second diagram described above,
The diode D11 and the transistor Q12 constitute a current mirror circuit, and the transistor Q14 and the transistor Q15 constitute a composite connection (Darlington connection) circuit. Also,
Transistor Q14 and transistor Q described above
15, each of the other transistors Q1 described above
Those having an emitter area larger than those of Nos. 1 to Q13 are used.

In the already proposed pulse output circuit shown in the second figure configured as described above, those input terminals 1
The input pulse signal supplied to the circuit is assumed to have a sufficiently high peak value to make the transistors Q11, Q12, Q14, and Q15 conductive due to its high-level voltage (or current). ing.

Now, considering that the input pulse signal supplied to the input terminal 1 is in a low level state, in this state, the transistor Q in the pulse output circuit shown in FIG.
Since transistors Q11 and Q14 are rendered non-conductive, transistors Q12 and Q15 are also rendered non-conductive. Therefore, since almost no current flows through the resistor R12 connected to the collector of the transistor Q12, the base voltage V13 of the transistor Q13 becomes a high level voltage approximately equal to the voltage value Vcc of the reference voltage source Vcc, and the diode D12
is placed in a non-conducting state.

In this way, when the input pulse signal supplied to the input terminal 1 is at a low level, the transistor Q15 is in a non-conducting state as described above, so that the transistor Q13 is connected from the output terminal 2 to the external load 3. A current flowing through is supplied, but
At this time, a high level signal having a voltage value lower than the base voltage V13 of the transistor Q13 by the base-emitter voltage VBE13 of the transistor Q13 appears at the output terminal 2.

Next, considering the state in which the input pulse signal supplied to the input terminal 1 is at a high level, in this state, the transistors Q11, Q14, and Q15 in the pulse output circuit shown in the second diagram are rendered conductive.
Furthermore, due to the conduction of the transistor Q11 described above, the transistor Q12 also becomes conductive. As described above, the current flowing due to conduction of the transistor Q12 is the current Ir12 flowing through the resistor R12 and the current flowing through the diode D12, that is, the resistor R1.
The current is the sum of the current Ir11 flowing through the transistor Q11 minus the base current of the transistor Q11. However, since the diode D11 and the transistor Q12 constitute a current mirror circuit, the transistor Q11 and the diode D11 have the above-mentioned current. The same current flows through transistor Q12.

And the base voltage V11 of transistor Q11
is determined according to the current flowing therein, and the base voltage V11 of the transistor Q11 mentioned above is determined according to the current flowing therein.
The current value of the current Ir11 flowing through the resistor R11 is determined based on the base voltage V13 of the transistor Q13, which is lowered by the anode-cathode voltage VD of the diode D12 from the base voltage V11 of the transistor Q11.
Since the current Ir12 flowing through the resistor R12 is determined based on the current Ir12 and the current flowing through the transistor Q12 is determined based on
The value of the current converges to a certain value.

Transistors Q13 have their base voltage V
13 is in a non-conducting state because the diode D12 is in a conductive state as described above and becomes a voltage lower than the base voltage of the transistor Q11 by the voltage VD between the anode and cathode of the diode D12, and As shown above, since the transistor Q15 in the compositely connected transistors Q14 and Q15 is conductive and saturated, the voltage at the output terminal 2 is the saturation voltage of the transistor Q15 itself, which is the voltage at the low level of the pulse signal. As mentioned above, since the transistors Q14 and Q15 have a larger emitter area than the other transistors Q11 to Q13, their emitter current density can be reduced. Therefore, the saturation voltage can be set to a small voltage.

In addition, transistor Q11 and transistor Q1
4 means that their bases are commonly connected,
Furthermore, since transistors Q14 and Q15 have larger emitter areas than transistor Q11,
Under the condition that the emitter current density of transistors Q14 and Q15 is the same as the emitter current density of transistor Q11, a large current can be passed through transistors Q14 and Q15, and output terminal 2 receives the input pulse supplied to input terminal 1. It is possible to send out a large current output pulse signal in which the signal is inverted and amplified.

(Problems to be Solved by the Invention) By the way, the previously proposed pulse output circuit shown in FIG. 2 has a problem in that the current value of the output pulse signal changes with changes in temperature.
In other words, since the voltage between the base and emitter of the transistor has a negative temperature characteristic (usually -2mv/℃), the input pulse signal supplied to input terminal 1 of the pulse output circuit becomes high level, and the transistor When Q15 becomes conductive and the temperature rises, the base voltage of transistor Q15 decreases, and the resistor R13 connected between the base and emitter of transistor Q15 has a positive temperature characteristic (usually +3000 ppm/℃). Since the current flowing through the resistor R13 decreases due to the increase in resistance value due to the rise in temperature, the current flowing through the resistor R13 decreases.
By increasing the base current of transistor Q15 and increasing the collector current, the current flowing through transistor Q15 will eventually decrease by ±50% for a temperature change of ±50°C.
will also change.

In this way, in the previously proposed pulse output circuit shown in Figure 2, the current value of the output pulse signal is affected by temperature fluctuations, so if the design is based on room temperature, the current will decrease at low temperatures. There is a problem of insufficient current and excessive current at high temperatures.
As a result, the load conditions are restricted, causing practical difficulties, and a solution to these problems has been sought.

(Means for Solving the Problems) In the present invention, an input pulse signal is supplied to the base via the first resistor, and the emitter is connected to the first diode in the forward direction. a first transistor whose base is connected to the emitter of the first transistor and whose collector is connected to a second transistor whose collector is connected to the reference voltage source.
A second transistor whose emitter is connected to a grounded source is connected to a reference voltage source through a resistor, an anode is connected to the base of the first transistor, and a cathode is connected to the collector of the second transistor. a second diode connected to the second diode, a third transistor whose base is connected to the collector of the second transistor and whose collector is connected to the reference voltage source; It has an emitter area larger than the emitter area of each transistor, and its base is connected to the base of the first transistor, its collector is connected to a reference voltage source, and its emitter is connected to the base of the first transistor. A fourth transistor is grounded through a series connection circuit of a third resistor and a fourth resistor, and has an emitter area larger than the emitter area of each of the first to third transistors described above. , a fifth transistor whose base is connected to the emitter of the fourth transistor and whose collector is connected to the emitter of the third transistor, the emitter of which is connected to ground; and the third resistor. a sixth transistor whose emitter is grounded, whose base is connected to the connection point between the transistor and the fourth resistor, and whose collector is connected to the base of the fifth transistor through a fifth resistor; and an output terminal for output pulses connected to the collector of the fifth transistor.

(Example) Hereinafter, specific contents of the pulse output circuit of the present invention will be explained in detail with reference to the accompanying drawings. FIG. 1 is a circuit diagram of an embodiment of the pulse output circuit of the present invention, in which 1 is an input terminal for an input pulse signal, 2 is an output terminal for an output pulse signal, and 3 is an external load. In the pulse output circuit of the present invention shown in FIG. 1, one end of the resistor R1 is connected to the input terminal 1, and the other end of the resistor R1 is connected to the base of the transistor Q1 and the base of the transistor Q4. It is connected to the anode of diode D2.

The emitter of the transistor Q1 is connected to the anode of the diode D1 and the base of the transistor Q2, and the cathode of the diode D1 is grounded. The collector of the transistor Q2 is connected to the cathode of the diode D2, one end of the resistor R2, and the base of the transistor Q3, and the other end of the resistor R2 is connected to the reference voltage source Vcc. There is. Further, the emitter of the transistor Q2 described above is grounded.

Transistor Q3 and transistor Q4 described above
The collector of the transistor Q3 is connected to the reference voltage source Vcc, and the emitter of the transistor Q3 is connected to the collector of the transistor Q5 and the output terminal 2. The emitter of the transistor Q5 is grounded, and the base thereof is connected to the emitter of the transistor Q4, one end of the resistor R3, and one end of the resistor R5. It is connected to the base of the transistor Q6 and one end of the resistor R4, and the other end of the resistor R4 is grounded. The collector of the transistor Q6 described above is connected to the other end of the resistor R5 described above, and the collector of the transistor Q6 is connected to the other end of the resistor R5 described above.
The emitter is grounded.

In the pulse output circuit shown in the first diagram described above,
The diode D1 and the transistor Q2 constitute a current mirror circuit, and the transistor Q4 and the transistor Q5 constitute a composite connection (Darlington connection) circuit. Further, as the transistor Q4 and the transistor Q5 described above, those having an emitter area larger than the emitter area of each of the other transistors Q1 to Q3 described above are used.

In the pulse output circuit of the present invention configured as described above, the input pulse signals supplied to the input terminals 1 of the transistors Q1 and Q2 are controlled by the high level voltage (or current). , Q4, and Q5 have a sufficiently high peak value to bring them into conduction.

Now, considering that the input pulse signal supplied to the input terminal 1 is in a low level state, in this state, the transistor Q in the pulse output circuit shown in FIG.
Since transistors Q1 and Q4 are rendered non-conductive, transistors Q2 and Q5 are also rendered non-conductive. Therefore, since almost no current flows through the resistor R2 connected to the collector of the transistor Q2, the base voltage V3 of the transistor Q3 becomes a high level voltage approximately equal to the voltage value Vcc of the reference voltage source Vcc, and the diode D2 is placed in a non-conducting state.

In this way, when the input pulse signal supplied to the input terminal 1 is at a low level, the transistor Q5 is in a non-conducting state as described above, so the transistor Q3 is connected from the output terminal 2 to the external load 3. At this time, a high level signal having a voltage value lower than the base voltage V3 of the transistor Q3 by the base-emitter voltage VBE3 of the transistor Q3 appears at the output terminal 2.

Next, considering a state in which the input pulse signal supplied to the input terminal 1 is at a high level, in this state, the transistors Q1, Q4, and Q5 in the pulse output circuit shown in FIG.
Due to the conduction of the transistor Q1 described above, the transistor Q2 also becomes conductive. As mentioned above, the current flowing due to conduction of the transistor Q2 is the sum of the current Ir2 flowing through the resistor R2 and the current flowing through the diode D2, that is, the current obtained by subtracting the base current of the transistor Q1 from the current Ir1 flowing through the resistor R1. Regarding the current, since the diode D1 and the transistor Q2 constitute a current mirror circuit, the same current flows through the transistor Q1 and the diode D1 as the current flowing through the transistor Q2 described above.

Then, the base voltage V1 of the transistor Q1
is determined according to the current flowing therein, and the current value of the current Ir1 flowing through the resistor R1 is determined based on the base voltage V1 of the transistor Q1, and furthermore, the base voltage V of the transistor Q1 is determined based on the base voltage V1 of the transistor Q1.
The current Ir2 flowing through the resistor R2 is determined based on the base voltage V3 of the transistor Q3, which is lowered by the anode-cathode voltage VD of the diode D2 from the voltage VD between the anode and cathode of the diode D2.
Since the current flowing through the parts is determined, by repeating the series of operations described above, the voltage and current values of each part described above converge to a certain value.

Transistors Q3 have their base voltage V3
However, as mentioned above, when the diode D2 becomes conductive, the voltage becomes lower than the base voltage of the transistor Q1 by the voltage D between the anode and cathode of the diode D2, so it becomes non-conductive.
In addition, as described above, since the transistor Q5 in the compositely connected transistors Q4 and Q5 is conductive and saturated, the voltage at the output terminal 2 is the voltage at which the saturation voltage of the transistor Q5 itself is the low level state of the pulse signal. However, as mentioned above, the transistors Q4,
Since Q5 has a larger emitter area than each of the other transistors Q1 to Q3, the emitter current density can be reduced, and the saturation voltage can therefore be set to a small value. can.

Further, the bases of the transistors Q1 and Q4 are commonly connected, and the transistors Q4 and Q5 are connected to each other in common.
Transistors Q4 and Q5 have a larger emitter area than that of transistors Q4 and Q5.
Under the condition that the emitter current density of transistor Q1 is the same as that of transistor Q1, a large current can be passed through transistors Q4 and Q5, and it is easy to obtain an output pulse with a large current value from output terminal 2. .

Further, as described above, the bases of the transistors Q1 and Q4 are commonly connected, and the base of the transistor Q2, whose emitter is connected to the ground, is connected to the emitter of the transistor Q1. , since the base of transistor Q5 whose emitter is grounded is connected to the emitter of the other transistor Q4, the currents of transistor Q2 and transistor Q5 change simultaneously. There is no difference in level in the falling part.

In this way, in the pulse output circuit shown in the first diagram, the input pulse signal supplied to the input terminal 1 is inverted and amplified, and an output pulse signal of a large current can be sent to the output terminal 2. It is.

Now, the pulse output circuit having the above-described configuration includes a transistor Q6, and a temperature compensation circuit that performs a temperature compensation operation by shunting the base current of the transistor Q5. Since it is provided in the base circuit of Q5, the magnitude of the output pulse signal hardly changes even with temperature changes.

Next, this point will be explained. As mentioned above, the emitter of transistor Q5 whose collector is connected to the emitter of transistor Q3 is grounded, and the base thereof is connected to the emitter of transistor Q3.
4 emitter, one end of resistor R3, and one end of resistor R5.
The other end of the resistor R3 is connected to the base of the transistor Q6 and one end of the resistor R4, and the other end of the resistor R4 is grounded. The collector of the transistor Q6 is connected to the other end of the resistor R5, and the emitter of the transistor Q6 is grounded.

As is well known, the temperature characteristic of the base-emitter voltage of a transistor depends on the current. Therefore, the rate of change of the base-emitter voltage of the transistor Q5, through which a large current flows, is the same as that of the base-emitter voltage of the transistor Q6. It is smaller than the rate of change of voltage, and both transistors Q
5. The rate of decrease in base voltage when the temperature rises in transistor Q6 is greater in transistor Q6. Therefore, the voltage ΔV=V5-V6 across the resistor R3 exhibits a positive temperature characteristic.

By the way, since the resistor R3 has a positive temperature characteristic, the current flowing through the resistor R3 has almost no temperature characteristic. On the other hand, the resistor R4 connected in series with the resistor R3 described above also has a positive temperature characteristic, and the current shunted to the resistor R4 exhibits a negative temperature characteristic.

Therefore, since the base current of transistor Q6 can be made to exhibit a predetermined positive temperature characteristic by appropriately setting the shunt ratio to resistor R4, the collector current of transistor Q5 can also be made to exhibit a predetermined positive temperature characteristic. Therefore, the base current of transistor Q5 is shunted to compensate for the positive temperature characteristic of hFE of transistor Q5, and the collector current of transistor Q5 is made approximately constant regardless of temperature changes. It is possible.

Note that the resistor R5 is provided to prevent the transistor Q4 from being destroyed when the transistor Q6 becomes saturated, and is not necessary for the original operation of the temperature compensation circuit.

(Effects) As is clear from the detailed explanation above, in the pulse output circuit of the present invention, the input pulse signal is supplied to the base via the first resistor, and the emitter is sequentially supplied to the base. a first transistor which is grounded via a first diode connected in the direction and whose collector is connected to a reference voltage source; a base which is connected to the emitter of the first transistor; a second transistor whose collector is connected to a reference voltage source via a second resistor and whose anode is connected to the base of the first transistor;
a second diode whose cathode is connected to the collector of the transistor; and a third diode whose base is connected to the collector of the second transistor and whose collector is connected to a reference voltage source.
The transistor has an emitter area larger than that of each of the first to third transistors described above, and its base is connected to the base of the first transistor described above, and its collector is connected to the reference voltage. a fourth transistor connected to the source and whose emitter is installed through a series connection circuit of a third resistor and a fourth resistor; and an emitter of each of the first to third transistors described above. The transistor has an emitter area larger than the area of the transistor, and has a base connected to the emitter of the fourth transistor and a collector connected to the emitter of the third transistor. The base of the transistor No. 5 is connected to the connection point between the third resistor and the fourth resistor, and the collector is connected to the base of the fifth transistor through the fifth resistor. The pulse output circuit of the present invention includes a sixth transistor whose emitters are connected to ground, and an output terminal for output pulses connected to the collector of the fifth transistor. transistor Q
4, each of the other transistors Q1 to Q3 as Q5
Since a device with a larger emitter area than that of
Not only can the change in the low level of the output pulse signal be reduced even when the temperature changes, but also the bases of the transistors Q1 and Q4 are commonly connected, and the transistors Q4, Since Q5 has a larger emitter area than that of transistor Q1, a large current flows through transistors Q4 and Q5 on the condition that the emitter current density of transistors Q4 and Q5 is the same as that of transistor Q1. , and it is easy to obtain an output pulse with a large current value from the output terminal 2. Furthermore, as mentioned above, the transistors Q1 and Q4 are
Their bases are commonly connected, and the base of transistor Q2 whose emitter is connected to ground is connected to the emitter of transistor Q1, and the base of transistor Q5 whose emitter is grounded is connected to the emitter of transistor Q1. Since it is connected to the emitter of the other transistor Q4, the currents of transistor Q2 and transistor Q5 change simultaneously, and therefore there is no step difference in the rising and falling parts of the output pulse signal. Furthermore, in the pulse output circuit of the present invention, a temperature compensation circuit that includes a transistor Q6 and performs temperature compensation by shunting the base current of the transistor Q5 is used. By providing this in the base path of transistor Q5, the magnitude of the output pulse signal hardly changes even with temperature changes.
Since it is possible to stably output a large current output pulse signal, the present invention can satisfactorily solve all the drawbacks of the previously proposed methods mentioned above.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the pulse output circuit of the present invention, and FIG. 2 is a circuit diagram of a previously proposed pulse output circuit. 1...Input terminal, 2...Output terminal, 3...External load, Q1 to Q6, Q11, Q12, Q13, Q
15...Transistor, D1, D2, D11, D
12...Diode, R1-R5, R11-R1
3...Resistance.

Claims (1)

[Claims] 1 The input pulse signal is supplied to the base via the first resistor, the emitter is grounded via the first diode connected in the forward direction, and the collector is connected to the reference voltage. a first transistor whose base is connected to the emitter of the first transistor and whose collector is connected to the reference voltage source via a second resistor; a second diode whose anode is connected to the base of the first transistor and whose cathode is connected to the collector of the second transistor;
a third transistor whose base is connected to the collector of the second transistor and whose collector is connected to a reference voltage source; and an emitter area larger than the emitter area of each of the first to third transistors. It has, and also,
The base is connected to the base of the first transistor, the collector is connected to a reference voltage source, and the emitter is grounded through a series connection circuit of a third resistor and a fourth resistor. The fourth transistor has a larger emitter area than the emitter area of each of the first to third transistors, and the fourth transistor has an emitter area larger than that of each of the first to third transistors.
a fifth transistor whose base is connected to the emitter of the above-mentioned transistor and whose collector is connected to the emitter of the above-mentioned third transistor, whose emitter is grounded; and the above-mentioned third resistor and fourth resistor. a sixth transistor whose base is connected to the connection point and whose collector is connected to the base of the fifth transistor through a fifth resistor, the emitter of which is connected to ground; and the collector of the fifth transistor which is connected to the base of the fifth transistor; and an output terminal for output pulses connected to the pulse output circuit.