阅读说明：本技术 带隙参考电压产生电路 (Bandgap reference voltage generating circuit ) 是由 吴昌宪 林俊谷 于 2020-01-09 设计创作，主要内容包括：本发明提供一种带隙参考电压产生电路,包含一参考电压产生电路、一电流产生电路、一分流电路以及一第一连接路径切换电路。参考电压产生电路在其第一与第二电流输入端形成一参考电压。电流产生电路的第一与第二输入端分别连接至第一与第二电流输入端。电流产生电路产生一第一电流,用以偏压参考电压产生电路。分流电路具有一电流输入端、一第一电流输出端以及一第二电流输出端。第一连接路径切换电路用以切换电流产生电路的第一输入端以及第二输入端与分流电路的第一电流输入端以及第二电流输入端之间的连接路径。(The invention provides a band-gap reference voltage generating circuit, which comprises a reference voltage generating circuit, a current generating circuit, a shunt circuit and a first connection path switching circuit. The reference voltage generating circuit forms a reference voltage at the first and second current input terminals thereof. The first and second input terminals of the current generating circuit are connected to the first and second current input terminals, respectively. The current generation circuit generates a first current for biasing the reference voltage generation circuit. The shunt circuit has a current input terminal, a first current output terminal and a second current output terminal. The first connection path switching circuit is used for switching connection paths between the first input end and the second input end of the current generating circuit and the first current input end and the second current input end of the shunt circuit.)

1. A bandgap reference voltage generating circuit, comprising:

a reference voltage generating circuit having a first current input terminal and a second current input terminal, the reference voltage generating circuit forming a reference voltage at the first current input terminal and the second current input terminal, respectively;

a current generating circuit having a first input terminal and a second input terminal, the first input terminal and the second input terminal being electrically connected to the first current input terminal and the second current input terminal, respectively, the current generating circuit being configured to generate a first current for biasing the reference voltage generating circuit;

a shunt circuit having a current input terminal, a first current output terminal and a second current output terminal, wherein the current input terminal receives the first current, and a voltage at the current input terminal of the shunt circuit is used as an output voltage of the bandgap reference voltage generating circuit; and

a first connection path switching circuit electrically connected between the current generating circuit and the shunt circuit for switching connection paths between the first input terminal and the second input terminal of the current generating circuit and the first current output terminal and the second current output terminal of the shunt circuit; and

a control circuit for generating a first control signal to periodically control the switching operation of the first connection path switching circuit.

2. The bandgap reference voltage generating circuit of claim 1, wherein the shunting circuit comprises a first resistor, a second resistor and a third resistor, one end of the first resistor is electrically connected to the current generating circuit and the other end is electrically connected to one end of the second resistor and one end of the third resistor, and the other end of the second resistor and the other end of the third resistor is electrically connected to the first connection path switching circuit.

3. The bandgap reference voltage generating circuit as claimed in claim 1, wherein the reference voltage generating circuit comprises a first bipolar junction transistor, a second bipolar junction transistor and a fourth resistor, the emitter of the first bipolar junction transistor is electrically connected to the first connection path switching circuit, the base and the collector of the first bipolar junction transistor are electrically connected to each other, the emitter of the second bipolar junction transistor is electrically connected to one end of the fourth resistor, the base and the collector of the second bipolar junction transistor are electrically connected to the base of the first bipolar junction transistor, the other end of the fourth resistor is electrically connected to the first connection path switching circuit, and the emitter area of the second bipolar junction transistor is multiple times the emitter area of the first bipolar junction transistor.

4. The bandgap reference voltage generating circuit as claimed in claim 1, wherein said first connecting path switching circuit comprises a first switch, a second switch, a third switch and a fourth switch, one end of said first switch and said second switch is electrically connected to said first current output terminal of said shunting circuit, and the other end of said first switch and said second switch is electrically connected to said first current input terminal and said second current input terminal of said reference voltage generating circuit respectively, one end of said third switch and said fourth switch is electrically connected to said second current output terminal of said shunting circuit, and the other end of said third switch and said fourth switch is electrically connected to said first current input terminal and said second current input terminal of said reference voltage generating circuit respectively.

5. The bandgap reference voltage generating circuit as claimed in claim 1, wherein said current generating circuit comprises a first operational amplifier, a signal filter and a MOS transistor, a first input terminal of said first operational amplifier is used as said first input terminal of said current generating circuit, a second input terminal of said first operational amplifier is used as said second input terminal of said current generating circuit, an output terminal of said first operational amplifier is electrically connected to an input terminal of said signal filter, an output terminal of said signal filter is electrically connected to a gate of said MOS transistor, a source of said MOS transistor receives a supply voltage, and a drain of said MOS transistor outputs said first current.

6. The bandgap reference voltage generating circuit as claimed in claim 1, wherein said current generating circuit comprises a second operational amplifier, a signal filter and a MOS transistor, a first input terminal of said second operational amplifier is used as said first input terminal of said current generating circuit, a second input terminal of said second operational amplifier is used as said second input terminal of said current generating circuit, an output terminal of said second operational amplifier is electrically connected to an input terminal of said signal filter, an output terminal of said signal filter is electrically connected to a gate of said MOS transistor, a source of said MOS transistor receives a supply voltage, and a drain of said MOS transistor outputs said first current;

the bandgap reference voltage generating circuit further comprises a second connection path switching circuit electrically connected between the current generating circuit and the first connection path switching circuit and used for switching a connection path between two input ends of the second operational amplifier of the current generating circuit and two output ends of the first connection path switching circuit;

wherein the polarities of the two input terminals of the second operational amplifier are interchangeable.

7. The bandgap reference voltage generating circuit as claimed in claim 6, wherein said control circuit generates a second control signal for periodically controlling the switching operation of said second connection path switching circuit and interchanging the polarities of said two input terminals of said second operational amplifier.

8. A bandgap reference voltage generating circuit, comprising:

a reference voltage generating circuit having a first current input terminal and a second current input terminal, the reference voltage generating circuit forming a reference voltage at the first current input terminal and the second current input terminal, respectively;

a current generating circuit having a first input terminal and a second input terminal, the first input terminal and the second input terminal being electrically connected to the first current input terminal and the second current input terminal, respectively, the current generating circuit being used for generating a first current for biasing the reference voltage generating circuit, wherein the current generating circuit comprises an operational amplifier, a signal filter and a MOS transistor, a first input terminal of the operational amplifier being used as the first input terminal of the current generating circuit, a second input terminal of the operational amplifier being used as the second input terminal of the current generating circuit, an output terminal of the operational amplifier being electrically connected to an input terminal of the signal filter, and polarities of the two input terminals of the operational amplifier being interchangeable, an output terminal of the signal filter being electrically connected to a gate of the MOS transistor, a source of the MOS transistor receiving a supply voltage, the drain electrode of the MOS transistor outputs the first current;

a shunt circuit having a current input terminal, a first current output terminal and a second current output terminal, wherein the current input terminal receives the first current, and a voltage at the current input terminal of the shunt circuit is used as an output voltage of the bandgap reference voltage generating circuit; and

a connection path switching circuit electrically connected between the current generating circuit and the reference voltage generating circuit for switching connection paths between the first input terminal and the second input terminal of the current generating circuit and the first current input terminal and the second current input terminal of the reference voltage generating circuit;

a control circuit for generating a first control signal to periodically control the switching operation of the connection path switching circuit, and a second control signal to periodically interchange the polarities of the two input terminals of the operational amplifier.

9. The bandgap reference voltage generating circuit of claim 8, wherein the shunting circuit comprises a first resistor, a second resistor and a third resistor, one end of the first resistor is electrically connected to the current generating circuit and the other end is electrically connected to one end of the second resistor and one end of the third resistor, and the other end of the second resistor and the other end of the third resistor are electrically connected to the connection path switching circuit.

10. The bandgap reference voltage generating circuit as claimed in claim 8, wherein said connection path switching circuit comprises a first switch, a second switch, a third switch and a fourth switch, one end of said first switch and said second switch is electrically connected to said first input terminal of said current generating circuit, the other end of said first switch and said second switch is electrically connected to said first current input terminal and said second current input terminal of said reference voltage generating circuit respectively, one end of said third switch and said fourth switch is electrically connected to said second input terminal of said current generating circuit, and the other end of said third switch and said fourth switch is electrically connected to said first current input terminal and said second current input terminal of said reference voltage generating circuit respectively.

Technical Field

The present invention relates to a bandgap reference voltage generating circuit, and more particularly, to a bandgap reference voltage generating circuit capable of preventing a reference voltage from being affected by temperature due to resistance errors.

Background

Referring to fig. 1, a simplified circuit diagram of a conventional bandgap reference voltage generating circuit is shown. As shown in fig. 1The conventional bandgap reference voltage generating circuit comprises at least two bipolar junction transistors Q₁And Q₂PMOS transistor M₁A plurality of resistors R_1A、R_1B、R₂And R₃And an operational amplifier OP. Resistance R₃Is electrically connected to the PMOS transistor M₁And a resistance R_1AR is a resistance_1AAnd a resistance R_1BOne end of which is electrically connected with the resistor R₃And a resistance R_1AAnd a resistance R_1BThe other end of the operational amplifier is electrically connected to the negative input end and the positive input end of the operational amplifier OP, respectively. Resistance R₂Is electrically connected to the resistor R_1BAnd a bipolar junction transistor Q₂Between the emitters of the two electrodes.

Bipolar junction transistor Q₁And Q₂Is a PNP bipolar junction transistor, and a bipolar junction transistor Q₂Is a PNP bipolar junction transistor Q₁Multiple times of so that the PNP bipolar junction transistor Q₂Base emitter voltage V_BE2Unlike PNP bipolar junction transistor Q₁VBE 1.

The feedback mechanism keeps the voltages at the two input terminals of the operational amplifier OP equal. When the resistance R is_1AIs equal to the resistance R_1BSo as to flow through the PNP bipolar junction transistor Q₁And Q₂Are equal. Due to PNP bipolar junction transistor Q₂Is a PNP bipolar junction transistor Q₁Multiple times of that of the PNP bipolar junction transistor Q₂Base-emitter voltage V of_BE2Unlike PNP bipolar junction transistor Q₁Base-emitter voltage V of_BE1PNP bipolar junction transistor Q₁Base-emitter voltage V of_BE1Minus PNP bipolar junction transistor Q₂Base-emitter voltage V of_BE2Is DeltaV_BEAnd a reference voltage V_OUTThe calculation of (c) is shown in the following equation (1).

Base-emitter voltage V due to forward conduction_BE1Having a negative temperature coefficient, i.e.Is negative and Δ V_BEIs a positive temperature coefficient, i.e.Positive values. Therefore, in order to obtain a temperature-independent reference voltage V_OUTI.e. byAdjustable parameterAs shown in equations (2) and (3) below.

In practice, however, the resistance R is controlled, even with precision_1AAnd a resistor R_1BThe resistance value of the reference voltage is still subject to error, so that the conventional bandgap reference voltage generation circuit can not effectively output the reference voltage V independent of the temperature_OUT. The resistance error described above will be explained below with respect to the reference voltage V_OUTInfluence of temperature dependence.

Assuming the resistance error is ε, as shown in equation (4), the current flows to the resistor R_1AAnd a resistor R_1BRespectively is I₁And I₂Through a resistance R₃Has a current of I₃. From equations (6) and (7), the reference voltage V can be derived_OUTWith respect to the resistance error epsilon, and equation (8) represents the reference voltage V_OUTTemperature dependence.

R_1A＝R₁(1+ε),R_1B＝R₁Equation (4)

Thus, if the resistance parameter is still adjusted according to equation (3), the reference voltage V_OUTIs still affected by temperature, and equation (9) represents the reference voltage V_OUTThe influence of temperature is related to the resistance error epsilon.

Disclosure of Invention

An objective of the present invention is to provide a bandgap reference voltage generating circuit to avoid the reference voltage of the bandgap reference voltage generating circuit from being affected by temperature due to the existence of resistance error.

According to an embodiment of the present invention, a bandgap reference voltage generating circuit includes a reference voltage generating circuit, a current generating circuit, a shunt circuit, a first connection path switching circuit, and a control circuit. The reference voltage generating circuit has a first current input terminal and a second current input terminal, and the reference voltage generating circuit forms a reference voltage at the first current input terminal and the second current input terminal respectively. The current generating circuit has a first input terminal and a second input terminal, and the first input terminal and the second input terminal are electrically connected to the first current input terminal and the second current input terminal, respectively. The current generation circuit generates a first current for biasing the reference voltage generation circuit. The shunt circuit has a current input terminal, a first current output terminal and a second current output terminal. The current input end receives the first current, wherein the voltage of the current input end of the shunt circuit is used as an output voltage of the bandgap reference voltage generating circuit. The first connection path switching circuit is electrically connected between the current generating circuit and the shunt circuit and is used for switching connection paths between the first input end and the second input end of the current generating circuit and the first current output end and the second current output end of the shunt circuit. The control circuit generates a first control signal to periodically control the switching operation of the first connection path switching circuit.

According to an embodiment, the shunt circuit may include a first resistor, a second resistor, and a third resistor. One end of the first resistor is electrically connected with the current generating circuit, the other end of the first resistor is electrically connected with one ends of the second resistor and the third resistor, and the other ends of the second resistor and the third resistor are electrically connected with the first connection path switching circuit.

According to one embodiment, the reference voltage generating circuit includes a first bipolar transistor, a second bipolar transistor and a fourth resistor. The emitter of the first bipolar junction transistor is electrically connected with the first connection path switching circuit, the base electrode and the collector of the first bipolar junction transistor are electrically connected with each other, the emitter of the second bipolar junction transistor is electrically connected with one end of the fourth resistor, the base electrode and the collector of the second bipolar junction transistor are electrically connected with the base electrode of the first bipolar junction transistor, and the other end of the fourth resistor is electrically connected with the first connection path switching circuit. The emitter area of the second bipolar junction transistor is a multiple of the emitter area of the first bipolar junction transistor.

According to an embodiment, the first connection path switching circuit includes a first switch, a second switch, a third switch and a fourth switch. One end of the first switch and one end of the second switch are electrically connected with the first current output end of the shunt circuit, the other end of the first switch and the other end of the second switch are electrically connected with the first current input end and the second current input end of the reference voltage generating circuit respectively, one end of the third switch and one end of the fourth switch are electrically connected with the second current output end of the shunt circuit, and the other end of the third switch and the other end of the fourth switch are electrically connected with the first current input end and the second current input end of the reference voltage generating circuit respectively.

According to one embodiment, the current generation circuit includes a first operational amplifier, a signal filter, and a MOS transistor. A first input terminal of the first operational amplifier is used as a first input terminal of the current generating circuit, a second input terminal of the first operational amplifier is used as a second input terminal of the current generating circuit, an output terminal of the first operational amplifier is electrically connected with an input terminal of the signal filter, an output terminal of the signal filter is electrically connected with a grid electrode of the MOS transistor, a source electrode of the MOS transistor receives a supply voltage, and a drain electrode of the MOS transistor outputs a first current.

According to one embodiment, the current generation circuit includes a second operational amplifier, a signal filter, and a MOS transistor. A first input terminal of the second operational amplifier is used as a first input terminal of the current generating circuit, a second input terminal of the second operational amplifier is used as a second input terminal of the current generating circuit, an output terminal of the second operational amplifier is electrically connected with an input terminal of the signal filter, an output terminal of the signal filter is electrically connected with a grid electrode of the MOS transistor, a source electrode of the MOS transistor receives a supply voltage, and a drain electrode of the MOS transistor outputs the first current. The bandgap reference voltage generating circuit further includes a second connection path switching circuit electrically connected between the current generating circuit and the first connection path switching circuit and configured to switch a connection path between two input terminals of a second operational amplifier of the current generating circuit and two output terminals of the first connection path switching circuit. The polarities of the two input ends of the second operational amplifier are interchangeable.

According to an embodiment, the control circuit generates a second control signal to periodically control the switching operation of the second connection path switching circuit and to interchange the polarities of the two input terminals of the second operational amplifier.

According to an embodiment of the present invention, a bandgap reference voltage generating circuit includes a reference voltage generating circuit, a current generating circuit, a shunt circuit, a connection path switching circuit, and a control circuit. The reference voltage generating circuit has a first current input terminal and a second current input terminal, and the reference voltage generating circuit forms a reference voltage at the first current input terminal and the second current input terminal respectively. The current generating circuit has a first input terminal and a second input terminal, the first input terminal and the second input terminal are electrically connected to the first current input terminal and the second current input terminal, respectively, and the current generating circuit is used for generating a first current for biasing the reference voltage generating circuit. The current generating circuit comprises an operational amplifier, a signal filter and a MOS transistor. A first input terminal of the operational amplifier is used as a first input terminal of the current generating circuit, a second input terminal of the operational amplifier is used as a second input terminal of the current generating circuit, an output terminal of the operational amplifier is electrically connected with an input terminal of the signal filter, the polarities of the two input terminals of the operational amplifier are interchangeable, an output terminal of the signal filter is electrically connected with the grid electrode of the MOS transistor, the source electrode of the MOS transistor receives a supply voltage, and the drain electrode of the MOS transistor outputs the first current. The shunt circuit has a current input terminal, a first current output terminal and a second current output terminal, wherein the current input terminal receives the first current. The voltage of the current input end of the shunt circuit is used as an output voltage of the band gap reference voltage generating circuit. The connection path switching circuit is electrically connected between the current generating circuit and the reference voltage generating circuit and is used for switching connection paths between the first input end and the second input end of the current generating circuit and the first current input end and the second current input end of the reference voltage generating circuit. The control circuit generates a first control signal to periodically control the switching operation of the connection path switching circuit, and a second control signal to periodically interchange the polarities of the two input terminals of the operational amplifier.

According to an embodiment, the shunt circuit includes a first resistor, a second resistor and a third resistor. One end of the first resistor is electrically connected with the current generating circuit, the other end of the first resistor is electrically connected with one ends of the second resistor and the third resistor, and the other ends of the second resistor and the third resistor are electrically connected with the connection path switching circuit.

According to an embodiment, the connection path switching circuit includes a first switch, a second switch, a third switch and a fourth switch. One end of the first switch and one end of the second switch are electrically connected with the first input end of the current generating circuit, the other end of the first switch and the other end of the second switch are electrically connected with the first current input end and the second current input end of the reference voltage generating circuit respectively, one end of the third switch and one end of the fourth switch are electrically connected with the second input end of the current generating circuit, and the other end of the third switch and the other end of the fourth switch are electrically connected with the first current input end and the second current input end of the reference voltage generating circuit respectively.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:

FIG. 1 is a schematic circuit diagram of a conventional bandgap reference voltage generating circuit;

FIG. 2 is a block diagram of a bandgap reference voltage generating circuit according to the present invention;

FIG. 3 is a schematic circuit diagram of a bandgap reference voltage generating circuit according to a first embodiment of the present invention;

FIGS. 4A and 4B are schematic circuit diagrams illustrating different operating states of a bandgap reference voltage generating circuit according to a first embodiment of the present invention;

FIG. 5 is a schematic circuit diagram of a bandgap reference voltage generating circuit according to a second embodiment of the present invention;

FIGS. 6A-6D are schematic circuit diagrams illustrating different operating states of a bandgap reference voltage generating circuit according to a second embodiment of the present invention;

FIG. 7 is a timing diagram of control signals of a bandgap reference voltage generating circuit according to a second embodiment of the present invention;

FIG. 8 is a schematic circuit diagram of a bandgap reference voltage generating circuit according to a third embodiment of the present invention;

fig. 9A to 9D are schematic circuit diagrams of different operating states of a bandgap reference voltage generating circuit according to a third embodiment of the present invention.

10: a current generating circuit;

101, a first input end;

102, a second input terminal;

20. 21, a shunt circuit;

a first current output terminal 201;

202, a second current output end;

203, a current input end;

a first connection path switching circuit 31;

32, a second connection path switching circuit;

a third connection path switching circuit 33;

40. reference voltage generating circuit;

401 a first current input;

402, a second current input terminal;

50, a control circuit;

501, a first control signal;

501a is an inverted signal of the first control signal;

502: a second control signal;

502a, an inverted signal of the second control signal;

503: a third control signal;

NF is a notch filter;

c is a capacitor;

I_B1a first current;

OP、OP₁、OP₂an operational amplifier;

R_1A、R_1B、R₂、R₃a resistor;

s1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 switches;

Q₁a first bipolar junction transistor;

Q₂a second bipolar junction transistor；

M₁A PMOS transistor.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided in conjunction with the drawings and examples, so that how to implement the technical means for solving the technical problems and achieving the technical effects of the present invention can be fully understood and implemented.

Please refer to fig. 2, which is a block diagram of a bandgap reference voltage generating circuit according to the present invention. As shown in fig. 2, the bandgap reference voltage generating circuit may include a current generating circuit 10, a shunt circuit 20, a first connection path switching circuit 31 and a reference voltage generating circuit 40.

The reference voltage generating circuit 40 has a first current input terminal 401 and a second current input terminal 402, and the reference voltage generating circuit 40 forms a reference voltage at the first current input terminal 401 and the second current input terminal 402 respectively. In one embodiment, the reference voltage generating circuit 40 may include a first bipolar transistor and a second bipolar transistor, and the emitter area of the second bipolar transistor is multiple times of the emitter area of the first bipolar transistor, which will be described in the following paragraphs.

The current generating circuit 10 has a first input terminal 101 and a second input terminal 102, wherein the first input terminal 101 and the second input terminal 102 are electrically connected to the first current input terminal 401 and the second current input terminal 402, respectively, for receiving the reference voltage. The current generation circuit 10 generates and outputs a first current I_B1First current I_B1Can flow into the reference voltage generating circuit 40 through the shunt circuit 20 and the first connection path switching circuit 31 to bias the reference voltage generating circuit 40.

The shunt circuit 20 has a current input terminal 203, a first current output terminal 201 and a second current output terminal 202, the current input terminal 203 receives the first current I_B1And the voltage at the current input terminal 203 is used as an output voltage of the bandgap reference voltage generating circuit. The currents flowing from the first current output terminal 201 and the second current output terminal 202 are in a predetermined ratio, for example, the current flowing from the first current output terminalThe current of 201 is equal to the current flowing from the second current output 202.

In one embodiment, the shunt circuit 20 may include a first resistor, a second resistor and a third resistor, one end of the first resistor is electrically connected to the current generating circuit 10, the other end of the first resistor is electrically connected to one end of the second resistor and one end of the third resistor, and the other end of the second resistor and the other end of the third resistor are electrically connected to the first connection path switching circuit 31. In a preferred embodiment, the second resistor and the third resistor have substantially the same resistance, so that the current flowing through the second resistor is substantially the same as the current flowing through the third resistor.

The first connection path switching circuit 31 is electrically connected between the current generating circuit 10 and the shunt circuit 20, and is used for switching connection paths between the first input terminal 101 and the second input terminal 102 of the current generating circuit 10 and the first current output terminal 201 and the second current output terminal 202 of the shunt circuit 20.

In an embodiment, the first connection path switching circuit 31 may include a first switch, a second switch, a third switch and a fourth switch, one end of the first switch and one end of the second switch are electrically connected to the first current output terminal 201 of the shunting circuit 20, the other end of the first switch and the other end of the second switch are electrically connected to the first current input terminal 401 and the second current input terminal 402 of the reference voltage generating circuit 40, one end of the third switch and one end of the fourth switch are electrically connected to the second current output terminal 202 of the shunting circuit 20, and the other end of the third switch and the other end of the fourth switch are electrically connected to the first current input terminal 401 and the second current input terminal 402 of the reference voltage generating circuit 40, respectively.

The control circuit 50 generates a first control signal 501 to periodically control the switching operation of the first link path switching circuit 31. For example, the first control signal 501 may periodically control the first switch, the second switch, the third switch, and the fourth switch, and when the first switch and the fourth switch are turned on, the second switch and the third switch are turned off; when the second switch and the third switch are turned on, the first switch and the fourth switch are turned off.

Ideally, from the first current outputThe currents flowing from the terminal 201 and the second current output terminal 202 have to satisfy a predetermined ratio, for example, the current flowing from the first current output terminal 201 is equal to the current flowing from the second current output terminal 202, thereby eliminating the reference voltage V_OUTTemperature dependence. The shunt circuit 20 is configured with two resistors to control the currents flowing from the first current output terminal 201 and the second current output terminal 202, and the resistance values of the two resistors are set such that the currents flowing from the first current output terminal 201 and the second current output terminal 202 conform to a predetermined ratio. However, in practical applications, even though the resistance values of the two resistors are precisely controlled, the resistance values of the two resistors have a slight difference e. The above illustrates that a slight difference epsilon between the resistance values of the two resistors affects the reference voltage V_OUTTemperature dependence.

Since the first connection path switching circuit 31 periodically switches the connection paths between the first input terminal 101 and the second input terminal 102 of the current generating circuit 10 and the first current output terminal 201 and the second current output terminal 202 of the shunt circuit 20, the first input terminal 101 of the current generating circuit 10 is periodically electrically connected to different resistors of the shunt circuit 20, and the second input terminal 102 of the current generating circuit 10 is also periodically electrically connected to different resistors of the shunt circuit 20, so that the difference of resistance values between the resistors of the shunt circuit 20 with respect to the reference voltage V can be effectively reduced_OUTInfluence of temperature dependence.

Please refer to fig. 3, fig. 4A and fig. 4B, which are a schematic circuit diagram of a bandgap reference voltage generating circuit according to a first embodiment of the present invention and schematic circuit diagrams of different operating states of the bandgap reference voltage generating circuit according to the first embodiment of the present invention, respectively.

As shown in fig. 3, the first embodiment of the bandgap reference voltage generating circuit may include a reference voltage generating circuit 41, a current generating circuit, a shunt circuit 21, and a first connection path switching circuit 31. The reference voltage generating circuit 41 includes a first bipolar transistor Q₁A second bipolar transistor Q₂And a resistor R₂. First bipolar junction transistor Q₁Emitter of the capacitor is electrically connectedThe current generating circuit is connected to receive the current generated by the current generating circuit. The base and collector of the first bipolar junction transistor Q1 are electrically connected to each other and to ground. Second bipolar junction transistor Q₂Is electrically connected to one end of a resistor R2, a second bipolar transistor Q₂The base and the collector of the first bipolar junction transistor Q are electrically connected₁The base of (1). Resistance R₂And the other end thereof is electrically connected to the first connection path switching circuit 31. Second bipolar junction transistor Q₂Having an emitter area of the first bipolar junction transistor Q₁Multiple times the emitter area.

The current generation circuit comprises an operational amplifier OP₁A signal filter, a PMOS transistor M₁And a capacitor C. In this embodiment, the signal filter is implemented by a notch filter NF, but the invention is not limited thereto. Capacitor C is electrically connected with PMOS transistor M₁. Operational amplifier OP₁A positive input end of the resistor R is electrically connected with the resistor R₂One end of, e.g. node ND₂And the negative input terminal is electrically connected with the first bipolar junction transistor Q₁Emitter of, e.g. node ND₁. Operational amplifier OP₁Is electrically connected to an input terminal of notch filter NF, and an output terminal of notch filter NF is electrically connected to PMOS transistor M₁A gate electrode of (1). Capacitor C is electrically connected with PMOS transistor M₁A source and a gate. PMOS transistor M₁A source receiving a supply voltage VDD, and a PMOS transistor M₁The drain electrode of (1) outputs a first current I_B1。

The notch filter NF may be coupled to the operational amplifier OP according to the third control signal 503₁The output signal of (a) is filtered. The frequency of the first control signal 501 is even times the frequency of the third control signal 503. in a preferred embodiment, the ratio of the frequency of the first control signal 501 to the frequency of the third control signal 503 is 2: 1.

The shunt circuit 21 includes a resistor R₃、R_1AAnd R_1BResistance R₃One end of which is electrically connected with the PMOS transistor M₁And a resistor R₃The other end of the resistor R is electrically connected with a resistor R_1AAnd R_1BTo one end of (a).

The first connection path switching circuit 31 includes a switch S1, a switch S2, a switch S3, and a switch S4. One ends of the switches S1 and S2 are electrically connected to the resistor R of the shunt circuit 21_1AAnd the other ends of the switches S1 and S2 are electrically connected to the node ND₂And ND₁One ends of the switches S3 and S4 are electrically connected to the resistor R of the shunt circuit 21_1BAnd the other ends of the switches S3 and S4 are electrically connected to the node ND₂And ND₁。

Switches S1 and S4 operate in synchronization, switches S2 and S3 operate in synchronization, and switches S1 and S4 operate in reverse to switches S2 and S3. In other words, when the switches S1 and S4 are turned on, the switches S2 and S3 are turned off, as shown in fig. 4A; when the switches S1 and S4 are closed, the switches S2 and S3 are turned on, as shown in fig. 4B.

The first link path switching circuit 31 receives a first control signal 501, and the switches S1, S2, S3 and S4 operate according to the first control signal 501. In practical applications, the first connection path switching circuit 31 may use an inverter to generate the inverted signal 501a of the first control signal 501, the first control signal 501 is used to control the switches S1 and S4, and the inverted signal 501a is used to control the switches S2 and S3; alternatively, the first control signal 501 is a signal group, and includes two control signals that are opposite in phase.

As described above, when the first connection path switching circuit 31 periodically switches the connection path, the operational amplifier OP₁Is periodically and sequentially electrically connected to the resistors R1A and R1B, and the operational amplifier OP₁Is periodically and sequentially electrically connected to the resistors R1B and R1A, thereby effectively reducing the resistance difference between the resistors R1A and R1B of the shunt circuit 20 to the output voltage V of the bandgap reference voltage generating circuit_OUTInfluence of temperature dependence.

Please refer to fig. 5, fig. 6A to fig. 6D, and fig. 7, which are schematic circuit diagrams of a second embodiment of a bandgap reference voltage generating circuit of the present invention, schematic circuit diagrams of different operating states of the second embodiment of the bandgap reference voltage generating circuit of the present invention, and a control signal timing diagram of the second embodiment of the bandgap reference voltage generating circuit of the present invention, respectively.

Ideally, the voltage difference between the two inputs of the operational amplifier should be 0V, but in practical applications, a voltage difference other than 0V still exists between the two inputs of the operational amplifier. In order to eliminate the voltage difference between the two input terminals of the operational amplifier, the operational amplifier may periodically switch the polarity of the two input terminals, and the second embodiment of the bandgap reference voltage generating circuit uses such an operational amplifier.

The second embodiment is different from the first embodiment in that the second embodiment further includes a second connection path switching circuit 32, and the current generating circuit includes an operational amplifier OP₂The polarity of the two inputs of (a) may be interchanged.

The second connection path switching circuit 32 is electrically connected between the current generating circuit 10 and the first connection path switching circuit 31, and is used for switching the operational amplifier OP of the current generating circuit 10₂And two output terminals (i.e., nodes ND3 and ND4) of the first connection path switching circuit 31.

The second connection path switching circuit 32 may include switches S5, S6, S7 and S8, wherein one end of the switches S5 and S6 is electrically connected to the operational amplifier OP₂And the other ends of the switches S5 and S6 are electrically connected to two output terminals of the first connecting path switching circuit 31, i.e., nodes ND3 and ND4, respectively. One end of the switches S7 and S8 is electrically connected to the operational amplifier OP₂And the other ends of the switches S7 and S8 are electrically connected to two output terminals of the first connecting path switching circuit 31, i.e., nodes ND3 and ND4, respectively.

Switches S5 and S8 operate in synchronization, switches S6 and S7 operate in synchronization, and switches S5 and S8 operate in reverse to switches S6 and S7. In other words, when the switches S5 and S8 are turned on, the switches S6 and S7 are turned off, as shown in fig. 6A and 6B; when the switches S5 and S8 are turned off, the switches S6 and S7 are turned on, as shown in fig. 6C and 6D.

The second connection path switching circuit 32 receives a second control signal 502, and the switches S5, S6, S7 and S8 operate according to the second control signal 502, and the second control signal 502 may include two signals for controlling the switches S5 and S8 and the switches S6 and S7, respectively; alternatively, the second connection path switching circuit 32 may include an inverter for generating the inverted signal 502a of the second control signal 502, the second control signal 502 for controlling the switches S5 and S8, and the inverted signal 502a of the second control signal 502 for controlling the switches S6 and S7; the same mechanism is also applicable to the first control signal 501, the first control signal 501 is used to control the switches S1 and S4, and the inverted signal 501a of the first control signal 501 is used to control the switches S2 and S3, as shown in FIG. 7.

In addition, an operational amplifier OP₂The polarities of the two input terminals can be interchanged according to the second control signal 502, for example, in FIG. 6A and FIG. 6B, the operational amplifier OP₂The first input terminal of (a) is a positive input terminal and the second input terminal is a negative input terminal; in FIGS. 6C and 6D, the operational amplifier OP₂The first input terminal of (a) is a negative input terminal and the second input terminal is a positive input terminal. The frequency of the first control signal 501, the frequency of the second control signal 502, and the frequency of the third control signal 503 are even multiples of each other, for example, the ratio of the frequency of the first control signal 501 to the frequency of the second control signal 502 is 1:2 or 2: 1; in a preferred embodiment, the frequency of the first control signal 501, the frequency of the second control signal 502, and the frequency of the third control signal 503 are 4:2:1, as shown in FIG. 7. In other words, the operational amplifier OP is performed every time₂After the polarities of the two input terminals are interchanged, the operational amplifier OP₂Each of which is electrically connected to the resistor R of the shunt circuit 21 in turn_1AAnd R_1BBy periodically performing the above operation, the resistance R of the shunt circuit 20 can be effectively reduced_1AAnd R_1BResistance value difference therebetween to the reference voltage V_OUTInfluence of temperature dependence.

Fig. 8, 9A and 9B are schematic circuit diagrams of a third embodiment of a bandgap reference voltage generating circuit of the invention and different operating states of the third embodiment of the bandgap reference voltage generating circuit of the invention, respectively.

The third embodiment is different from the above embodiments in that the connection path switching circuit 33 of the third embodiment is electrically connected between the current generating circuit and the reference voltage generating circuit 41, and the current generating circuit includes an operational amplifier OP₂The polarity of the two inputs of (a) may be interchanged.

The connection path switching circuit 33 may switch a connection path between two input terminals of the current generating circuit and two current input terminals of the reference voltage generating circuit 41 according to the first control signal 501. Operational amplifier OP₂The polarity of the two input terminals can be interchanged according to a second control signal 502, and the frequency of the second control signal 502 is even times the frequency of the first control signal 501, and in a preferred embodiment, the frequency of the first control signal 501, the frequency of the second control signal 502, and the frequency of the third control signal 503 are 4:2: 1.

The connection path switching circuit 33 includes switches S9, S10, S11, and S12. One end of each of the switches S9 and S10 is electrically connected to the operational amplifier OP₂The first input terminal of, i.e. node ND₆The other ends of the switches S9 and S10 are electrically connected to the bipolar junction transistor Q₁Emitter and resistor R₂One end of each of the switches S11 and S12 is electrically connected to the operational amplifier OP₂A second input terminal of, i.e. node ND₅The other ends of the switches S11 and S12 are electrically connected to the bipolar junction transistor Q₁Emitter and resistor R₂。

Switches S9 and S12 operate in synchronization, switches S10 and S11 operate in synchronization, and switches S9 and S12 operate in reverse to switches S10 and S11. In other words, when the switches S9 and S12 are turned on, the switches S10 and S11 are turned off, as shown in fig. 9A and 9B; when the switches S9 and S12 are turned off, the switches S10 and S11 are turned on, as shown in fig. 9C and 9D. In practical applications, the connection path switching circuit 33 may use an inverter to generate the inverted signal of the second control signal 502, the second control signal 502 is used to control the switches S9 and S12, and the inverted signal of the second control signal 502 is used to control the switches S10 and S11.

In a preferred embodiment, the first control signal 50The ratio of the frequency of 1 to the frequency of the second control signal 502 is 2:1, in other words, each time the operational amplifier OP₂After the polarities of the two input terminals are interchanged, the operational amplifier OP₂Each of which is electrically connected to a bipolar junction transistor Q in sequence₁Emitter and resistor R₂Therefore, the influence of the difference between the resistance values of the resistors R1A and R1B can be periodically applied to the operational amplifier OP₂Two input terminals of (1). Thus, the resistance R of the shunt circuit 21 can be effectively reduced_1AAnd R_1BResistance value difference therebetween to the reference voltage V_OUTInfluence of temperature dependence.

Although the present invention has been described with reference to the foregoing embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.