WO2023231828A1

WO2023231828A1 - Bandgap reference voltage circuit, integrated circuit, and electronic device

Info

Publication number: WO2023231828A1
Application number: PCT/CN2023/095725
Authority: WO
Inventors: 欧阳振华
Original assignee: 芯海科技（深圳）股份有限公司
Priority date: 2022-06-02
Filing date: 2023-05-23
Publication date: 2023-12-07
Also published as: CN115145340B; CN115145340A

Abstract

The present application discloses a bandgap reference voltage circuit, an integrated circuit, and an electronic device. The bandgap reference voltage circuit comprises: a voltage generation circuit, used for generating a first voltage, wherein the first voltage is a voltage having a temperature coefficient characteristic; a switched capacitor circuit, connected to the voltage generation circuit, the switched capacitor circuit comprising a capacitor unit and the switched capacitor circuit being used for generating a capacitance voltage by controlling the state of the capacitor unit; and a voltage output circuit, used for outputting a reference voltage according to the first voltage and the capacitance voltage. Therefore, the bandgap reference voltage circuit of the present application can reduce an offset voltage introduced into the outputted reference voltage, and reduce the influence of the offset voltage.

Description

Bandgap reference voltage circuits, integrated circuits and electronic equipment

Cross-references to related applications

This application claims priority from the Chinese application No. 202210626139.1 filed on June 2, 2022, the entire content of which is hereby incorporated by reference for all purposes.

Technical field

The present application relates to the field of electronic technology, and more specifically, to a bandgap reference voltage circuit, an integrated circuit and an electronic device.

Background technique

The bandgap reference voltage source can provide a stable reference voltage within a wide voltage range and a wide temperature range. It is an indispensable part of various analog and mixed-signal circuit systems and is widely used in communications, medical testing, image and audio and other fields. .

At present, the bandgap reference voltage source usually includes a current mirror and a resistor. Due to a certain mismatch in the current mirror layout and resistor, an offset voltage will be introduced into the output reference voltage and the temperature coefficient will be increased.

Contents of the invention

In view of the above problems, the present invention proposes a bandgap reference voltage circuit, an integrated circuit and an electronic device to improve the above problems.

In a first aspect, embodiments of the present application provide a bandgap reference voltage circuit, wherein the bandgap reference voltage circuit includes: a voltage generation circuit for generating a first voltage; wherein the first voltage has a temperature coefficient a characteristic voltage; a switched capacitor circuit connected to the voltage generating circuit, the switched capacitor circuit including a capacitor unit, the switched capacitor circuit being used to control the state of the capacitor unit state to generate a capacitor voltage; a voltage output circuit configured to output a reference voltage according to the first voltage and the capacitor voltage.

In a second aspect, embodiments of the present application further provide an integrated circuit, which includes the bandgap reference voltage circuit described in the first aspect.

In a third aspect, embodiments of the present application also provide an electronic device. The electronic device includes a device body and an integrated circuit as described in the second aspect provided in the device body.

In the technical solution provided by the present invention, the bandgap reference voltage circuit includes a voltage generation circuit for generating a first voltage; wherein the first voltage is a voltage with temperature coefficient characteristics; a switched capacitor circuit is connected to the voltage generation circuit , the switched capacitor circuit includes a capacitor unit, the switched capacitor circuit is used to generate a capacitor voltage by controlling the state of the capacitor unit; a voltage output circuit is used to output a reference voltage according to the first voltage and the capacitor voltage. Therefore, the bandgap reference voltage circuit can be less affected by the manufacturing process based on the capacitance, thereby reducing the offset voltage introduced in the output reference voltage.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. Not all examples. Based on the embodiments of the present application, all other embodiments and drawings obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Figure 1 shows a schematic structural diagram of a traditional structure band gap reference voltage circuit.

FIG. 2 shows a schematic structural diagram of a bandgap reference voltage circuit provided by an embodiment of the present application.

FIG. 3 shows a schematic structural diagram of yet another bandgap reference voltage circuit provided by an embodiment of the present application.

Figure 4 shows a schematic structural diagram of another bandgap reference voltage circuit provided by an embodiment of the present application.

FIG. 5 shows a schematic structural diagram of yet another bandgap reference voltage circuit provided by an embodiment of the present application.

Figure 6 shows a schematic structural diagram of yet another bandgap reference voltage circuit provided by an embodiment of the present application.

Figure 7 shows a waveform diagram of a clock signal provided by an embodiment of the present application.

Figure 8 shows a schematic structural diagram of yet another bandgap reference voltage circuit provided by an embodiment of the present application. picture.

FIG. 9 shows a schematic structural diagram of yet another bandgap reference voltage circuit provided by an embodiment of the present application.

FIG. 10 shows an example structural diagram of a bandgap reference voltage circuit provided by an embodiment of the present application.

Figure 11 shows a circuit equivalent diagram provided by an embodiment of the present application.

Figure 12 shows another circuit equivalent diagram provided by the embodiment of the present application.

Figure 13 shows a schematic structural diagram of an integrated circuit provided by an embodiment of the present application.

Figure 14 shows a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Detailed ways

The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and cannot be understood as limiting the present application.

In order to enable those in the technical field to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of this application.

Reference in this specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Therefore, in this specification, the terms "including", "includes", "having" and their variations all mean "including but not limited to" unless otherwise specifically emphasized. It should be pointed out that

In the embodiment of this application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between two electrical components. For example, A and B may be connected directly, or A and B may be connected indirectly through one or more other electrical components.

The bandgap reference voltage source can provide a stable reference voltage within a wide voltage range and a wide temperature range. It is an indispensable part of various analog and mixed-signal circuit systems and is widely used in communications, medical Testing, image audio and other fields.

The traditional bandgap reference voltage source usually adopts the circuit structure shown in Figure 1. The negative feedback terminal of the operational amplifier OP1 makes the voltages of the positive and negative input terminals of the operational amplifier OP1 equal. Under different current densities, the base-emitter voltage difference of bipolar transistors PNP1 and PNP2 has a negative temperature coefficient, which acts on resistor R1. The generated current is mirrored to resistor R2 through current mirrors MP1 and MP3, and has a positive temperature coefficient. The base-emitter voltages of the coefficient bipolar transistor PNP3 compensate each other to form a reference voltage that changes little with temperature. However, in this circuit structure, due to the layout mismatch of current mirrors MP1 and MP3, there will be an offset voltage in the output voltage. Under the CMOS process, there will be a certain mismatch in the ratio of resistors R1 and R2, which will also introduce offset voltage into the output voltage, thus increasing the temperature coefficient.

In order to solve the above problems, the inventor has proposed the bandgap reference voltage circuit, integrated circuit and electronic device in the embodiment of the present application after long-term research. The bandgap reference voltage circuit includes a voltage generation circuit for generating a first voltage; wherein, The first voltage is a voltage with temperature coefficient characteristics; a switched capacitor circuit is connected to the voltage generating circuit, the switched capacitor circuit includes a capacitor unit, and the switched capacitor circuit is used to generate electricity by controlling the state of the capacitor unit. capacitor voltage; a voltage output circuit configured to output a reference voltage according to the first voltage and the capacitor voltage. This application uses a capacitor to output the reference voltage, which can reduce the offset voltage introduced in the output reference voltage compared to the traditional circuit structure that outputs the reference voltage through a resistor.

Referring to FIG. 2 , FIG. 2 shows a bandgap reference voltage circuit 100 provided by an embodiment of the present application. The bandgap reference voltage circuit 100 includes a voltage generating circuit 110 , a switched capacitor circuit 120 and a voltage output circuit 130 . The voltage generation circuit 110 is used to generate a first voltage. The first voltage is a voltage with temperature coefficient characteristics, that is, the first voltage can be a voltage with a positive temperature coefficient or a voltage with a negative temperature coefficient. The switched capacitor circuit 120 is connected to the voltage. The generating circuit 110 and the switched capacitor circuit 120 include a capacitor unit 121, and the switched capacitor circuit 120 is used to generate a capacitor voltage by controlling the state of the capacitor unit 121. The voltage output circuit 130 is used to output a reference voltage according to the first voltage and the capacitor voltage.

The bandgap reference voltage circuit 100 of the embodiment of the present invention outputs a reference voltage using the design of a resistor-free switched capacitor circuit, so that the output reference voltage is less affected by the device process, thereby reducing the introduction of offset voltage into the output reference voltage. .

In some embodiments, the voltage generation circuit 110 is also used to generate a second voltage, and the second voltage is a voltage with temperature coefficient characteristics, that is, the second voltage may be a voltage with a positive temperature coefficient or a voltage with a negative temperature coefficient. In this embodiment, the first voltage and the second voltage have the same temperature coefficient. The difference between the first voltage and the second voltage is a voltage having an opposite temperature coefficient to the first voltage or the second voltage. Voltage. The switched capacitor circuit may generate a capacitor voltage based on the first voltage and the second voltage.

In some embodiments, please refer to FIG. 3 , which shows yet another bandgap reference voltage circuit 100 provided by an embodiment of the present application. Among them, the switched capacitor circuit 120 includes a switch unit 122, and the switch unit 122 is used to control the state of the capacitor unit 121.

As shown in another bandgap reference voltage circuit 100 in FIG. 4 , the switch unit 122 may include a first switch branch 1221 and a second switch branch 1222 . When the first switch branch 1221 is turned on and the second switch branch 1222 is turned off, the capacitor unit 121 discharges so that the charge amount of the capacitor unit 121 reaches the preset range; when the first switch branch 1221 is turned off and the second switch branch is turned off, When the switch branch 1222 is turned on, the capacitor unit 121 is connected to the voltage generation circuit 110 and the voltage output circuit 130 respectively, and the capacitor unit 121 is charged to generate a capacitor voltage.

In this embodiment, the state of the capacitor unit 121 can be controlled by controlling the connection state of the first switch branch 1221 and the second switch branch 1222. When the first switch branch 1221 is turned on and the second switch branch 1222 is turned off, the capacitor unit 121 may be in a discharge state, and the amount of charge existing on the capacitor unit 121 will gradually decrease until it reaches a preset range. As a In this implementation, the preset range may be approximately equal to or equal to zero. In this state, the capacitor unit 121 will continue to discharge until its charge amount is approximately equal to or equal to zero. When the first switch branch 1221 is turned off and the second switch branch 1222 is turned on, the capacitor unit 121 can be connected to the voltage generation circuit 110 and the voltage output circuit 130 respectively, so that the capacitor unit 121 is in a charging state. The corresponding capacitor voltage can be generated by charging.

In some embodiments, such as another bandgap reference voltage circuit 100 shown in FIG. 5 , the capacitor unit 121 may include a first capacitor C1 and a second capacitor C2. Then, the capacitor voltage includes the first capacitor voltage and the second capacitor voltage. Among them, the switched capacitor circuit 120 controls the discharge of the first capacitor C1 and the second capacitor C2 so that the charges of the first capacitor C1 and the second capacitor C2 respectively reach the preset range. The switched capacitor circuit 120 controls the first capacitor C1 and the second capacitor C2. The capacitor C2 is charged to generate a first capacitor voltage corresponding to the first capacitor C1 and a second capacitor voltage corresponding to the second capacitor C2 according to the first voltage and the second voltage. The voltage output circuit 130 may be based on the charge of the first capacitor C1 and the charge amount of the second capacitor C2, and output a reference voltage according to the first capacitor voltage and the second capacitor voltage.

As an implementation manner, the bandgap reference voltage circuit 100 can control the states of the first capacitor C1 and the second capacitor C2 by controlling the connection state of the first switch branch 1221 and the second switch branch 1222 . When the first switch branch 1221 is turned on and the second switch branch 1222 is turned off, both the first capacitor C1 and the second capacitor C2 are in a discharge state. The amount of charge will gradually decrease until its amount of charge is approximately equal to or equal to zero. When the first switch branch 1221 is turned off and the second switch branch 1222 is turned on, both the first capacitor C1 and the second capacitor C2 are at least connected to the voltage output circuit 130, and both the first capacitor C1 and the second capacitor C2 are charging. state, so that the first capacitor C1 has a corresponding first capacitor voltage, and the second capacitor C2 has a corresponding second capacitor voltage. According to the principle of conservation of charge, the voltage output circuit 130 can be based on the first capacitor C1 and the second capacitor C2 before and after charging and discharging. The sum of the charges, and the reference voltage is output according to the first capacitor voltage and the second capacitor voltage.

As a specific example, the first switch branch 1221 may include a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4. Among them, the first switch S1 is connected to the output end of the voltage output circuit 130, one end of the second switch S2 is connected to the second switch branch 1222 and the first capacitor C1 respectively, the other end of the second switch S2 is grounded, and the third switch S3 One end of the third switch S3 is connected to the first capacitor C1 and the second capacitor C2 respectively, the other end of the third switch S3 is connected to the ground, and one end of the fourth switch S4 is connected to the second switch branch 1222 and the second capacitor C2 respectively. The other end is connected to ground. The second switch branch 1222 may include a fifth switch S5, a sixth switch S6, and a seventh switch S7. Among them, one end of the fifth switch S5 is connected to the input end of the voltage output circuit 130, the other end of the fifth switch S5 is connected to one end of the third switch S3, one end of the sixth switch S6 is connected to the voltage generating circuit 110, and the sixth switch S5 is connected to the input end of the voltage output circuit 130. The other end of S6 is connected to the first capacitor C1 and one end of the second switch S2 respectively. One end of the seventh switch S7 is connected to the output end of the voltage output circuit 130 . The other end of the seventh switch S7 is connected to the second capacitor C2 and the second switch S2 respectively. Four terminals of switch S4 are connected.

When the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are closed, and the fifth switch S5, the sixth switch S6, and the seventh switch S7 are opened, that is, the first switch branch 1221 is connected, When the second switch branch 1222 is turned off, the first capacitor C1 and the second capacitor C2 are connected in parallel and are not connected to the voltage generation circuit 110 and the voltage output circuit 130 , that is, they are not connected to the bandgap reference voltage circuit 100 . At this time, both the first capacitor C1 and the second capacitor C2 are in a discharge state.

When the charge amounts on the first capacitor C1 and the second capacitor C2 reach the preset range, for example, when the charge amounts on the first capacitor C1 and the second capacitor C2 are both discharged to zero, the first switch S1, The second switch S2, the third switch S3, and the fourth switch S4 are turned off, and the fifth switch S5, the sixth switch S6, and the seventh switch S7 are turned on. That is, the first switch branch 1221 is turned off and the second switch branch 1222 is connected. At this time, the first capacitor C1 and the second capacitor C2 are reconnected to the bandgap reference voltage circuit 100, thereby entering the charging state, and generating the first capacitor voltage corresponding to the first capacitor C1 and the second capacitor C2 The corresponding second capacitor voltage, according to the principle of charge conservation, the sum of the charges of the first capacitor C1 and the second capacitor C2 before and after charging and discharging remains unchanged. After the first capacitor voltage and the second capacitor voltage stabilize, the voltage output circuit 130 It can be based on the charge amount of the first capacitor C1 and the charge amount of the second capacitor C2, and according to the first capacitance voltage and the second capacitor voltage output reference voltage.

In some embodiments, as shown in FIG. 6 , there is still another bandgap reference voltage circuit 100 , wherein the bandgap reference voltage circuit 100 may also include a clock generation circuit 140 , the clock generation circuit 140 is used to provide the switch unit 122 with The clock signal is used to enable the switch unit 122 to control the state of the capacitor unit 121 through the clock signal.

As an implementation manner, the clock signal may include a first clock signal and a second clock signal. Among them, the first clock signal can be used to control the switch unit 122 to discharge the capacitor unit 121, that is, to control the first switch branch 1221 to turn on and the second switch branch 1222 to turn off, so as to discharge the capacitor unit 121; the second clock signal It can be used to control the switch unit to charge the capacitor unit 121, that is, to control the first switch branch 1221 to turn off and the second switch branch 1222 to turn on, so as to charge the capacitor unit 121; where the first clock signal and the second clock The signals have opposite phases. For example, the waveform diagrams of the first clock signal and the second clock signal are as shown in Figure 7. In the initial stage, the first clock signal CLK1 is high level, the second clock signal CLK2 is low level, and the capacitor unit 121 begins to discharge. When the charge amount of the capacitor unit 121 reaches the preset range, the first clock signal CLK1 becomes low level, the second clock signal CLK2 becomes high level, the capacitor unit 121 starts charging and generates a capacitor voltage, and the voltage output circuit is sufficient A stable reference voltage is output according to the first voltage generated by the voltage generating circuit and the capacitor voltage.

The clock generating circuit 140 can also be arranged inside the switched capacitor circuit, which is not limited here.

In some embodiments, as shown in FIG. 8 , the voltage output circuit 130 may include an operational amplifier OP1. A first input terminal D1 of the operational amplifier OP1 is connected to the voltage generating circuit 110. A second input terminal D2 and an output terminal of the operational amplifier OP1 Terminal D3 is connected to the switched capacitor circuit 120 . When the capacitor unit 121 is discharging, the output terminal D3 of the operational amplifier OP1 is connected to the second input terminal D2; when the capacitor unit 121 is charging, the output terminal D3 and the second input terminal D2 of the operational amplifier OP1 are connected to the capacitor unit 121 respectively. to the output reference voltage.

In some embodiments, as shown in FIG. 9 , the voltage generation circuit 110 may also include a current mirror circuit 111 and a temperature compensation circuit 112 . The current mirror circuit 111 is used to generate an input current, and the temperature compensation circuit 112 is used to generate a first voltage and a second voltage according to the input current provided by the current mirror circuit 111 .

As an implementation manner, the current mirror circuit 111 may include a first current branch, a second current branch and a third current branch. Wherein, the input terminals of the first current branch, the second current branch and the third current branch are connected to the power supply voltage, the first current branch generates an input current according to the power supply voltage, and the second current branch The output ends of the circuit and the third current branch are respectively connected to the temperature compensation circuit 112, and the second input current and the third input current are respectively input to the temperature compensation circuit 112, wherein the second current branch and the third current branch are respectively The second input current and the third input current to the temperature compensation circuit 112 are both mirrored from the input current

Exemplarily, the first current branch includes at least a first transistor, the second current branch includes at least a first transistor, and the first transistor includes at least a third transistor. The source electrode of the first transistor, the source electrode of the second transistor, and the source electrode of the third transistor are all connected to the power supply voltage, and the gate electrodes of the first transistor, the gate electrode of the second transistor, and the gate electrode of the third transistor are connected to each other, and Commonly connected to the drain of the first transistor, the drain of the first transistor is grounded, and the drain of the second transistor is connected to the temperature compensation circuit 112 and the voltage output circuit 130 respectively. The gate of the third transistor is connected to the gate of the second transistor, and the drain of the third transistor is connected to the temperature compensation circuit 112 and the switched capacitor circuit 120 respectively. The bandgap reference voltage circuit 100 generates an input current through the first transistor, mirrors the input current through the second transistor and the third transistor respectively, and inputs the mirrored second input current and the third input current into the temperature compensation circuit 112 respectively. . The structure of the above-mentioned current mirror circuit 111 is only an example. The current mirror circuit 111 may also include current mirrors with other structures, which are not limited here.

In some embodiments, the temperature compensation circuit 112 at least includes a first triode unit and a second triode unit, wherein the ratio of the number of triodes in the first triode unit and the second triode unit is 1: N, N is a positive integer. The emitter of the first triode unit is connected to the current mirror circuit 111 and the voltage output circuit 130 respectively, and the base and collector of the first triode unit are grounded. The emitter of the second transistor unit is connected to the current mirror circuit 111 and the switched capacitor circuit 120 respectively, and the base and collector of the second transistor unit are grounded. Among them, the voltage drop between the emitter and base of the PN junction of the triode has a negative temperature coefficient, and under unequal current densities, the voltage difference between the first triode unit and the second triode unit has a positive temperature coefficient. coefficient, then, by adding the voltages of the positive and negative temperature coefficients, the voltage that changes little with temperature can be obtained. This application utilizes the above characteristics of the triode tube and cooperates with the switched capacitor circuit to output a reference voltage that changes little with temperature.

In order to better understand the present application, as an example, please refer to Figure 10. The bandgap reference voltage circuit 100 may include a current mirror circuit 111, a temperature compensation circuit 112, a switched capacitor circuit 120, a voltage output circuit 130 and a clock generation circuit. 140. The current mirror circuit 111 includes a first transistor MP1, a second transistor MP2, and a third transistor MP3. The number of MP2 and MP3 is the same. Voltage output circuit 130 includes operational amplifier OP1. The temperature compensation circuit 112 includes a first transistor unit PNP1 and a second transistor unit PNP2. The number ratio of PNP1 and PNP2 is 1:N. The switched capacitor circuit 120 may include a first capacitor C1, a second capacitor C2, a first switch S1, a second switch Switch S2, third switch S3, fourth switch S4, fifth switch S5, sixth switch S6 and seventh switch S7. The clock generation circuit 140 may include a first clock signal CLK1 and a second clock signal CLK2. The waveform diagrams of the first clock signal CLK1 and the second clock signal CLK2 are as shown in the above-mentioned FIG. 7 and have the same period but opposite phases.

When the switches S1, S2, S3, and S4 are closed and the switches S5, S6, and S7 are open, the circuit equivalent diagram of the bandgap reference voltage 100 is shown in Figure 11. At this time, the first capacitor C1 and the second capacitor C2 are connected in parallel and are not connected to the bandgap reference voltage circuit 100. The first capacitor C1 and the second capacitor C2 begin to discharge until the first capacitor C1 and the second capacitor C2 are stored. The charge is cleared. At this time, the sum of the charge Q ₁ of the first capacitor C1 and the charge Q ₂ of the second capacitor C2 is zero, that is, Q ₁ + Q ₂ =0.

The second input terminal of the operational amplifier OP1 is connected to the input terminal to form a unit gain output mode, and the output voltage of the operational amplifier OP1 is V _be1 .

When switches S5, S6, and S7 are closed and switches S1, S2, S3, and S4 are opened, the circuit equivalent diagram of the bandgap reference voltage 100 is shown in Figure 12. At this time, both the first capacitor C1 and the second capacitor C2 are connected to the gap reference voltage 100. One end of the first capacitor C1 is connected to the output end of the operational amplifier OP1, and the other end is connected to the second input end and the second input end of the operational amplifier OP1 respectively. One end of the second capacitor C2 and the other end of the second capacitor are connected to the emitter of the second transistor unit PNP2, and the first capacitor C1 and the second capacitor C2 are in a charging state.

Among them, the first input current is I ₀ . Since the number ratio of PNP1 and PNP2 is 1:N, the emitter-base voltage of PNP1 (i.e. the first voltage) is:

The emitter-base voltage (i.e. the second voltage) of PNP2 is:

Among them, I ₀ is the current flowing through the collector of PNP1, _IS is the saturation current of the bipolar transistor, V _T =kT/q, k is Boltzmann's constant, q is the electron charge, and T is the temperature.

Therefore, the voltage difference ΔV _be between the emitter-base of PNP1 and PNP2 is:
ΔV _be =V _be1 -V _be2 =V _T ln N

Because the voltage at the first input terminal and the second input terminal of the operational amplifier OP1 is the same, both are V _be1 , Therefore, the voltage across the first capacitor C1 (i.e., the voltage of the first capacitor) is:
U1＝V _be2 -V _be1

The voltage across the second capacitor C2 (i.e., the voltage of the second capacitor) is:
U2＝V _out -V _be1

Among them, V _out is the reference voltage output by the band gap reference voltage 100.

According to the principle of conservation of charge, the sum of the charges of the first capacitor C1 and the second capacitor C2 before and after charging and discharging remains unchanged, and Q ₁ + Q ₂ = 0 after discharge. It is assumed that the first capacitor C1 and the second capacitor C2 are stable after charging. In the state, the capacitances are C1 and C2 respectively. After charging, the sum of the charges of the first capacitor C1 and the second capacitor C2 is:
Q1+Q2＝U1·C1+U2·C2＝0

Right now,
Q1+Q2＝(V _be2 -V _be1 )·C1+(V _out -V _be )·C2＝0

Therefore, the output voltage of the operational amplifier OP1, that is, the reference voltage V _out output by the band gap reference voltage 100 is:

Because the voltage difference between the emitter-base of the triode has a negative temperature coefficient, △V _be has a positive temperature coefficient under different current densities, so adding the voltages of the positive and negative temperature coefficients can give a random The temperature change of the reference voltage is small, and the reference voltage is different from the structure of the traditional band gap reference voltage circuit. The capacitor structure is used instead of the resistor structure. Since the capacitor ratio accuracy is higher than the resistor ratio accuracy in the CMOS process, it can be reduced. The voltage in the output reference introduces an offset voltage.

Referring to FIG. 13 , FIG. 13 shows an integrated circuit 200 provided by an embodiment of the present application. The integrated circuit 200 includes the above-mentioned bandgap reference voltage circuit 100 .

Referring to FIG. 14 , FIG. 14 shows an electronic device 300 provided by an embodiment of the present application. The electronic device 300 includes a device body and the above-mentioned integrated circuit 200 . Among them, the integrated circuit 200 is provided in the main body of the device.

In this embodiment, the electronic device 300 may be a mobile phone or a smart phone (eg, iPhone TM-based, Android TM-based phone), a portable game device (eg, Nintendo DS TM, PlayStation Portable TM, Gameboy Advance TM, iPhone TM), laptop, PDA (Personal Digital Assistant, personal handheld computer), portable Internet devices, music players and data storage devices, other handheld devices such as watches, headphones, pendants, etc., the electronic device 300 can also be other wearable devices (for example, such as Electronic glasses, electronic clothes, electronic bracelets, electronic necklaces, electronic tattoos or head-mounted devices (HMD) for smart watches).

The electronic device 300 may also be any one of a plurality of electronic devices 300 including, but not limited to, cellular phones, smart phones, other wireless communication devices, personal digital assistants, audio players, other media players, music Recorders, video recorders, cameras, other media recorders, radios, medical equipment, vehicle transportation equipment, calculators, programmable remote controls, pagers, laptop computers, desktop computers, printers, netbooks, personal digital assistants (PDAs) , portable multimedia players (PMP), Moving Picture Experts Group (MPEG-1 or MPEG-2) audio layer 3 (MP3) players, portable medical devices, and digital cameras and combinations thereof.

To sum up, this application provides a bandgap reference voltage circuit, an integrated circuit and an electronic device. The bandgap reference voltage circuit includes a voltage generation circuit for generating a first voltage; wherein the first voltage has a temperature a voltage with coefficient characteristics; a switched capacitor circuit connected to the voltage generating circuit, the switched capacitor circuit including a capacitor unit, the switched capacitor circuit is used to generate a capacitor voltage by controlling the state of the capacitor unit; a voltage output circuit with A reference voltage is output according to the first voltage and the capacitor voltage. Therefore, the bandgap reference voltage circuit of the present application can reduce the offset voltage introduced into the output reference voltage and output a relatively stable reference voltage.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that: it can still Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent substitutions are made to some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions in the embodiments of the present application.

Claims

A bandgap reference voltage circuit, characterized in that the bandgap reference voltage circuit includes:

A voltage generation circuit, configured to generate a first voltage; wherein the first voltage is a voltage with temperature coefficient characteristics;

a switched capacitor circuit, connected to the voltage generating circuit, the switched capacitor circuit including a capacitor unit, the switched capacitor circuit being used to generate a capacitor voltage by controlling the state of the capacitor unit;

A voltage output circuit, configured to output a reference voltage according to the first voltage and the capacitor voltage.
The bandgap reference voltage circuit according to claim 1, wherein the voltage generation circuit is also used to generate a second voltage; wherein the second voltage is a voltage with temperature coefficient characteristics;

The switched capacitor circuit generates the capacitor voltage based on the first voltage and the second voltage.
The bandgap reference voltage circuit according to claim 2, wherein the capacitor unit includes a first capacitor and a second capacitor; the capacitor voltage includes a first capacitor voltage and a second capacitor voltage;

The switched capacitor circuit controls the discharge of the first capacitor and the second capacitor so that the charge amounts of the first capacitor and the second capacitor respectively reach the preset range;

The switched capacitor circuit controls the charging of the first capacitor and the second capacitor to generate a first capacitor voltage corresponding to the first capacitor and a first capacitor voltage corresponding to the first capacitor according to the first voltage and the second voltage. The voltage of the second capacitor corresponding to the two capacitors;

The voltage output circuit is based on the charge amount of the first capacitor and the charge amount of the second capacitor, and outputs the reference voltage according to the first capacitor voltage and the second capacitor voltage.
The bandgap reference voltage circuit according to claim 1, wherein the switched capacitor circuit further includes a switch unit, and the switch unit is used to control the state of the capacitor unit.
The bandgap reference voltage circuit according to claim 4, wherein the switch unit includes a first switch branch and a second switch branch;

When the first switch branch is turned on and the second switch branch is turned off, the capacitor unit discharges so that the charge amount of the capacitor unit reaches a preset range;

When the first switch branch is turned off and the second switch branch is turned on, the capacitor units are respectively connected to Connected to the voltage generating circuit and the voltage output circuit, the capacitor unit is charged to generate the capacitor voltage.
The bandgap reference voltage circuit according to claim 5, characterized in that the first switch branch includes a first switch, a second switch, a third switch and a fourth switch, and the first switch and the voltage The output end of the output circuit is connected, one end of the second switch is connected to the second switch branch and the first capacitor respectively, the other end of the second switch is connected to ground, and one end of the third switch is connected to The first capacitor and the second capacitor are connected, the other end of the third switch is connected to ground, and one end of the fourth switch is connected to the second switch branch and the second capacitor respectively. The other end of the four-switch is connected to ground;

The second switch branch includes a fifth switch, a sixth switch and a seventh switch. One end of the fifth switch is connected to the input end of the voltage output circuit, and the other end of the fifth switch is connected to the third switch. One end of the three switches is connected, one end of the sixth switch is connected to the voltage generating circuit, the other end of the sixth switch is connected to one end of the first capacitor and the second switch respectively, and the seventh switch One end of the switch is connected to the output end of the voltage output circuit, and the other end of the seventh switch is connected to one end of the second capacitor and the fourth switch respectively.
The bandgap reference voltage circuit according to any one of claims 4 to 6, characterized in that the bandgap reference voltage circuit further includes a clock generation circuit, the clock generation circuit is used to provide a clock signal to the switch unit , so that the switch unit controls the state of the capacitor unit through the clock signal.
The bandgap reference voltage circuit according to claim 7, wherein the clock signal includes a first clock signal and a second clock signal, and the first clock signal is used to control the conduction of the first switch branch. , the second switch branch is turned off to discharge the capacitor unit; the second clock signal is used to control the first switch branch to be turned off and the second switch branch to be turned on, so that the capacitor unit is discharged. The capacitive unit is charged, wherein the first clock signal and the second clock signal have opposite phases.
The bandgap reference voltage circuit according to claim 1, wherein the voltage output circuit includes an operational amplifier, and the first input end of the operational amplifier is connected to the voltage generating circuit, The second input terminal and output terminal of the operational amplifier are respectively connected to the switched capacitor circuit;

When the capacitor unit is charging, the output terminal and the second input terminal of the remote amplifier are respectively connected to the capacitor unit for outputting the reference voltage.
The bandgap reference voltage circuit according to claim 1, wherein the voltage generation circuit includes a current mirror circuit and a temperature compensation circuit;

The current mirror circuit is used to generate input current;

The temperature compensation circuit is used to generate a first voltage and a second voltage according to the input current.
An integrated circuit, characterized by comprising the bandgap reference voltage circuit according to any one of claims 1 to 10.
An electronic device, characterized in that it includes a device main body and an integrated circuit as claimed in claim 11 provided in the device main body.