JPH0822337A - Constant-voltage generating circuit - Google Patents

Abstract

PURPOSE:To enable the constant-voltage generating circuit, which utilizes transistors(TR) and has small temperature dependency, to output not only a voltage which is an integral multiple of about 1.2V, but also a voltage having an optional value. CONSTITUTION:The collector of an NPN TR Q1 is connected to a power source, the emitter of the Q1 is connected to an output, and the base of the Q1 is connected to a current source which has one end connected to a power source and the collector of an NPN TR Q2; and the emitter of the Q2 is grounded, the base of the Q2 is connected to a resistor R1 having one end connected to the output and the collector of an NPN TR Q3. The emitter of the Q3 is connected to a resistor R3 having one end grounded, and the base of the Q3 is connected to a resistor R2 having one end connected to the output, the collector and base of the NPN TR Q4 and the collector and base of an NPN TR Q5; and the emitter of the Q4 is grounded and the emitter of the Q5 is connected to a resistor R4 having one end grounded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is about 1.2V when it is attempted to obtain an output voltage having a small temperature dependence as in the prior art.
The present invention relates to a constant voltage generating circuit having a small temperature dependence, which uses a transistor capable of outputting an arbitrary voltage as well as an integral multiple of.

[0002]

2. Description of the Related Art In many cases, electronic circuits often have a constant voltage generating circuit having small temperature dependence inside the circuit. Among them, a circuit that is often used is called a band gap circuit.
When an attempt is made to reduce the temperature dependence, only an output voltage that is an integral multiple of about 1.2V can be obtained. Therefore, when an attempt is made to obtain any other voltage, measures such as using an amplifier are taken.

FIG. 4 is a diagram showing an example of the configuration of a conventional constant voltage generating circuit (band gap circuit). In FIG. 4, the collector current I _C13 of the NPN transistor Q ₁₃ is
It is expressed by the following equation.

I _C13 = (V _BE14 -V _BE13 ) / R ₁₃ = VT × N / R ₁₃ Therefore, the output voltage V _OUT is V _OUT = V _BE12 + R ₁₁ × I _C13 = V _BE12 + R ₁₁ (VT × N / R ₁₃ ). Here, VT is a constant proportional to the absolute temperature T, N
= LN ( _IE14 / _IE13 ) (N is a constant), and _VBE
Has a negative characteristic with respect to temperature.

Since VT has a positive characteristic with respect to temperature, an output voltage V _OUT having extremely small temperature dependence can be obtained by appropriately selecting the resistance value.

[0006]

However, according to the conventional example, when an attempt is made to reduce the temperature dependence due to the characteristics of the transistor, only an output voltage that is an integral multiple of about 1.2 V can be obtained. There is a drawback in that when an attempt is made to obtain a voltage of 1, it is necessary to take measures such as using an amplifier.

The present invention can output not only an integral multiple of about 1.2V but also an arbitrary voltage as in the conventional case without deteriorating the temperature dependence without taking measures such as using an amplifier. The present invention provides a constant voltage generating circuit that enables the above.

[0008]

In order to solve the above-mentioned problems, the first constant voltage generating circuit of the present invention comprises a first NP
The collector of the N-transistor is connected to the power supply, and the first NP
A second current source in which the emitter of the N-transistor is connected to the output and the base of the first transistor is connected to the power supply
Of the second NPN transistor is connected to the collector of the second NPN transistor, and the emitter of the second NPN transistor is grounded.
The base of the transistor is connected to the first resistor whose one end is connected to the output and the collector of the third NPN transistor, and the emitter of the third NPN transistor is connected to the third resistor whose one end is grounded. A second resistor and a fourth NPN whose one end is connected to the output of the base of the NPN transistor.
A circuit in which the collector / base of the transistor and the collector / base of the fifth NPN transistor are connected, the emitter of the fourth NPN transistor is grounded, and the emitter of the fifth NPN transistor is connected to the fourth resistor whose one end is grounded. Is.

In order to solve the above-mentioned problems, the second constant voltage generating circuit of the present invention connects the emitter of the first PNP transistor to the power supply and the collector / base of the first PNP transistor to the second. The base of the PNP transistor, the base of the sixth NPN transistor, and the collector of the third NPN transistor, the emitter of the second PNP transistor is connected to the power supply, and the collector of the second PNP transistor is connected to the output. , The collector of the sixth NPN transistor is connected to the power supply, the emitter of the sixth NPN transistor is connected to the second resistor whose one end is grounded,
The emitter of the third NPN transistor is connected to a third resistor whose one end is grounded, the base of the third NPN transistor is connected to the output of the first resistor, the collector-base of the fourth NPN transistor, and the 5 is a circuit in which the collector / base of the NPN transistor 5 is connected, the emitter of the fourth NPN transistor is grounded, and the emitter of the fifth NPN transistor is connected to a fourth resistor whose one end is grounded.

In order to solve the above-mentioned problems, the third constant voltage generating circuit of the present invention uses the first resistor having the collector of the first NPN transistor connected to the output and the inverting input terminal of the amplifier. And connecting the emitter of the first NPN transistor to a third resistor whose one end is grounded,
First with the base of the PN transistor connected to the output
Connected to the collector of the second NPN transistor, the collector base of the second NPN transistor, the collector base of the third NPN transistor and the non-inverting input terminal of the amplifier, the emitter of the second NPN transistor is grounded, and the third NPN transistor In this circuit, the emitter is connected to a fourth resistor whose one end is grounded, and the output of the amplifier is connected to the output.

[0011]

With the above structure, the constant voltage generating circuit of the first invention has a structure in which the NPN transistor Q ₅ and the resistor R ₄ are added to the conventional constant voltage generating circuit (band gap circuit) of FIG. Collector current I _C3 of NPN transistor Q ₃
Is expressed by the following equation.

I _C3 = (V _BE4 −V _BE3 ) / R ₃ = VT × NT ₁ / R ₃ Therefore, the output voltage V _OUT is V _OUT = V _BE2 + R ₁ × I _C3 = V _BE2 + R ₁ (VT × NT ₁ / R ₃ ). Here, VT is a constant proportional to the absolute temperature T, and V _BE has a negative characteristic with respect to temperature. _{Further, NT 1 = LN (I E4} / I E3) I E4 = {(V OUT -V BE4) / R 2} -I E5 I E5 = (V BE4 over _{V BE5) / R 4 = VT} × NT 2 / Although it is R ₄ , and N in the conventional example is almost constant, NT ₁ can set the temperature characteristic arbitrarily by the value of R ₄ .

Therefore, the output voltage V _OUT is about 1.2 V when the temperature dependence is reduced as in the conventional example.
That is, an output voltage that is an integral multiple of is not obtained, and an output voltage having a small temperature dependency can be obtained at an arbitrary voltage.

The constant voltage generating circuit of the second invention operates almost the same as the constant voltage generating circuit of the first invention, except that a current mirror circuit of PNP transistors is used.

Collector current I of NPN transistor Q _23
C23 is I _C23 = (V _BE24 -V _BE23 ) / R ₂₃ = VT × NT ₂₁ / R ₂₃ , and thus the output voltage V _OUT is V _OUT = V _BE24 + R ₂₁ × I _C22 = V _BE24 + R ₂₁ × I _C23 = V _BE24 + R ₂₁ (VT × NT ₂₁ / R ₂₃ ). Here, VT is a constant proportional to the absolute temperature T, and V _BE has a negative characteristic with respect to temperature. _{Further, NT 21 = LN (I E24} / I E23) I E24 = {(V OUT -V BE24) / R 21} -I E25 I E25 = (V BE24 over _{V BE25) / R 24 = VT} × NT 22 / Although it is R ₂₄ and N in the conventional example is almost constant, NT ₂₁ can set the temperature characteristic arbitrarily by the value of R ₂₄ .

Therefore, the output voltage V _OUT is about 1.2 V when the temperature dependence is reduced as in the conventional example.
That is, an output voltage that is an integral multiple of is not obtained, and an output voltage having a small temperature dependency can be obtained at an arbitrary voltage.

The constant voltage generating circuit of the third invention operates almost the same as the constant voltage generating circuit of the first invention, except that an amplifier is used.

NPN transistor Q₃₁Collector current I
_C31Is I_C31= (V_BE32-V_BE31) / R₃₃ = VT x NT₃₁/ R₃₃ Therefore, the output voltage V_OUTIs V_OUT= V_BE32+ R₃₂× I_C32  = V_BE32+ R₃₂× I_C31(R₃₂/ R₃₁) = V_BE32+ R₃₂(VT x NT₃₁/ R₃₃) (R₃₂/ R₃₁). Here, VT is a constant proportional to the absolute temperature T.
And V_BEHas a negative characteristic with respect to temperature. Also, NT₃₁= LN (I_E32/ I_E31) I_E32= {(V_OUT-V_BE32) / R₃₂} -I_E33 I_E33= (V_BE32-V_BE33) / R₃₄ = VT x NT₃₂/ R₃₄ In the conventional example, N was almost constant.₃₁Is
R₃₄The temperature characteristic can be set arbitrarily by the value of
It

Therefore, the output voltage V _OUT is about 1.2 V when the temperature dependence is reduced as in the conventional example.
That is, an output voltage that is an integral multiple of is not obtained, and an output voltage having a small temperature dependency can be obtained at an arbitrary voltage.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A constant voltage generating circuit according to an embodiment of the first invention will be described in detail with reference to FIG.

A current source in which the collector of the NPN transistor Q ₁ is connected to the power supply, the emitter of Q ₁ is connected to the output, and the base of Q ₁ is connected to the power supply and the NPN transistor Q.
Connected to the _second collector, the emitter grounded of the Q _2, Q
The _second base connected to the collector of the resistor R1 and the NPN transistor Q ₃ having one end connected to the output, its emitter connected to the Q3 to the resistor R ₃ which is grounded at one end, to connect the base of Q ₃ to the output end In a configuration in which the resistor R ₂ is connected to the collector / base of the NPN transistor Q _{4 and} the collector / base of the NPN transistor Q ₅ , the emitter of Q ₄ is grounded, and the emitter of Q ₅ is connected to the resistor R ₄ whose one end is grounded. is there.

Next, the operation of this embodiment configured as described above will be described. In the circuit of FIG. 1, the collector current I _C3 of Q ₃ is I _C3 = (V _BE4 −V _BE3 ) / R ₃ = VT × NT ₁ / R ₃ , and thus the output voltage V _OUT is V _OUT = V _{BE2 + R 1 × I C3 =} V BE2 + R 1 (VT × NT 1 / R 3) become. Here, VT is a constant proportional to the absolute temperature T, and V _BE has a negative characteristic with respect to temperature. _{Further, NT 1 = LN (I E4} / I E3) I E4 = {(V OUT -V BE4) / R 2} -I E5 I E5 = (V BE4 -V BE5) / R 4 = VT × NT 2 / Since R ₄ is NT ₄ , the temperature characteristic of NT ₁ can be arbitrarily set by the value of R ₄ .

Therefore, the output voltage V _OUT can be obtained at an arbitrary voltage when the temperature dependence is to be reduced.

The constant voltage generating circuit of one embodiment of the second invention will be described in detail with reference to FIG.

The emitter of the PNP transistor Q ₂₁ is connected to the power supply, and the collector / base of Q ₂₁ is connected to the base of the PNP transistor Q _{22 and} the base of the NPN transistor Q ₂₆ to N.
Connect to the collector of PN transistor Q ₂₃ , connect the emitter of Q ₂₂ to the power supply, connect the collector of Q ₂₂ to the output,
The collector of Q ₂₆ is connected to a power source, connecting the emitter of NPN transistor Q ₂₃ is connected to the emitter of Q ₂₆ to the resistor R ₂₂ which is grounded at one end to the resistor R ₂₃ which is grounded at one end, one end of the base of Q ₂₃ A resistor R ₂₁ connected to the output, the collector / base of the NPN transistor Q ₂₄ and the NPN transistor Q ₂₅
Of it connected to the collector-base, emitter grounded in Q _24, a configuration of connecting the emitter of Q ₂₅ to the resistor R ₂₄ in which one end grounded.

Next, the operation of this embodiment configured as described above will be described. In the circuit of FIG. 2, the collector current I _C23 of Q ₂₃ is I _C23 = (V _BE24 −V _BE23 ) / R ₂₃ = VT × NT ₂₁ / R ₂₃ , and thus the output voltage V _OUT is V _OUT = V _BE24 + R ₂₁ × I _C22 = V _BE24 + R ₂₁ × I _C23 = V _BE24 + R ₂₁ (VT × NT ₂₁ / R ₂₃ ). Here, VT is a constant proportional to the absolute temperature T, and V _BE has a negative characteristic with respect to temperature.

[0027] _{NT 21 = LN (I E24 /} I E23) I E24 = {(V OUT -V BE24) / R 21} -I E25 I E25 = (V BE24 over _{V BE25) / R 24 = VT} × NT 22 / R ₂₄ , and NT ₂₁ can arbitrarily set the temperature characteristics by the value of R ₂₄ .

Therefore, the output voltage V _OUT can be obtained as an arbitrary voltage when the temperature dependence is to be reduced.

A constant voltage generating circuit according to an embodiment of the third invention will be described in detail with reference to FIG.

NPN transistor Q₃₁One end of the collector
Resistor R connected to the output₃₁And amplifier inverting input terminal connection
Then Q₃₁Resistor R whose one end is grounded₃₃Connected to
Then Q ₃₁R with one end connected to the output₃₁And N
PN transistor Q₃₂Collector base and NPN tiger
Register Q₃₃Collector-base and amplifier non-inverting input terminal
Connect to the child, Q₃₂Ground the emitter of₃₃The emitter of
Resistor R with one end grounded ₃₄To the output of the amplifier.
It is a structure that connects to force.

Next, the configuration of the present embodiment constructed as described above
The operation will be described. In the circuit of Figure 3, NPN transition
Star Q₃₁Collector current I_C31Is I_C31= (V_BE32-V_BE31) / R₃₃ = VT x NT₃₁/ R₃₃ Therefore, the output voltage V_OUTIs V_OUT= V_BE32+ R₃₂× I_C32  = V_BE32+ R₃₂× I_C31(R₃₂/ R₃₁) = V_BE32+ R₃₂(VT x NT₃₁/ R₃₃) (R₃₂/ R₃₁) Where VT is a constant proportional to absolute temperature T, and V_BE
Has a negative characteristic with respect to temperature. Also, NT₃₁= LN (I_E32/ I_E31) I_E32= {(V_OUT-V_BE32) / R₃₂} -I_E33 I_E33= (V_BE32-V_BE33) / R₃₄ = VT x NT₃₂/ R₃₄ And NT₃₁Is R₃₄Temperature characteristics can be set arbitrarily by the value of
become able to.

Therefore, the output voltage V _OUT can be obtained as an arbitrary voltage when the temperature dependence is to be reduced.

[0033]

As described above in detail, the constant voltage generating circuit of the present invention can obtain an output voltage having a small temperature dependency at an arbitrary voltage by appropriately selecting the resistance value.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of a constant voltage generating circuit of the first invention.

FIG. 2 is a circuit diagram of an embodiment of a constant voltage generating circuit of the second invention.

FIG. 3 is a circuit diagram of an embodiment of a constant voltage generating circuit of a third invention.

FIG. 4 is a circuit diagram of a conventional example.

[Explanation of symbols]

I _1, I ₁₁ current source 30 amplifier _{Q 1 ~Q 5, Q 11 ~Q} 14, Q 23 ~Q 26, Q 31 ~Q 33 NP
N transistors Q _21, Q _22, PNP transistor _{R 1 ~R 4, R 11 ~R} 13, R 21 ~R 24, R 31 ~R 34 resistance

Claims (3)

[Claims] 1. A current source having a collector of a first NPN transistor connected to a power supply, an emitter of the first NPN transistor connected to an output, and a base of the first transistor connected at one end to a power supply and a second source. The collector of the NPN transistor is connected, the emitter of the second NPN transistor is grounded, and the base of the second NPN transistor is connected to the collector of the first resistor and the collector of the third NPN transistor whose one end is connected to the output. The emitter of the third NPN transistor is connected to a third resistor whose one end is grounded,
The NPN transistor base is connected to the second resistor whose one end is connected to the output, the collector base of the fourth NPN transistor and the collector base of the fifth NPN transistor, and the emitter of the fourth NPN transistor is grounded. A constant voltage generating circuit characterized in that the emitter of the fifth NPN transistor is connected to a fourth resistor whose one end is grounded. 2. The emitter of the first PNP transistor is connected to a power source, and the collector of the first PNP transistor is connected.
The base is the base of the second PNP transistor and the sixth N
The base of the PN transistor and the collector of the third NPN transistor are connected, the emitter of the second PNP transistor is connected to the power supply, the collector of the second PNP transistor is connected to the output, and the collector of the sixth NPN transistor is connected. Connected to a power supply, connected the emitter of the sixth NPN transistor to the second resistor whose one end is grounded, and connected the third NP
The emitter of the N-transistor is connected to a third resistor whose one end is grounded, and the base of the third NPN transistor is connected to the output of a first resistor, the collector-base of the fourth NPN transistor and the fifth NPN. A constant voltage generating circuit, which is connected to the collector / base of a transistor, the emitter of a fourth NPN transistor is grounded, and the emitter of a fifth NPN transistor is connected to a fourth resistor whose one end is grounded. 3. The collector of the first NPN transistor is connected to a first resistor whose one end is connected to the output and the inverting input terminal of the amplifier, and the emitter of the first NPN transistor is connected to a third resistor whose one end is grounded. A first resistor having the base of the first NPN transistor connected to the output and the collector / base of the second NPN transistor and the third N
The collector / base of the PN transistor and the non-inverting input terminal of the amplifier are connected, the emitter of the second NPN transistor is grounded, and the emitter of the third NPN transistor is connected to the fourth resistor whose one end is grounded. A constant voltage generation circuit characterized in that the output is connected to the output.