CN103207636B - A kind of for providing the circuit of low-noise band-gap reference voltage source - Google Patents

Abstract

The invention provides a kind of for providing the circuit of bandgap voltage reference, bandgap voltage reference provides the electric current of multichannel slightly temperature coefficient, and the temperature coefficient of electric current offsets the temperature coefficient of the resistance adopted in reference voltage source just.The bandgap voltage reference of zero-temperature coefficient is produced by current flowing resistance, the low-pass filter that a cutoff frequency is very low is connect after bandgap voltage reference, the noise filtering of bandgap voltage reference, thus provide different electric current for modules different in RF chip in SIM cards of mobile phones.

Description

A circuit for providing a low noise bandgap voltage reference

technical field

The invention relates to the field of bandgap reference voltage sources, in particular to a low-noise bandgap reference voltage source.

Background technique

The radio frequency RF chip needs to provide a low-noise bandgap reference voltage source for the radio frequency RF module, and it is not allowed to interfere with the low-noise bandgap reference voltage source when each module is working. The traditional method is to plug a large capacitance. Filter the bandgap reference with a bulk capacitor.

However, there are the following problems in filtering the bandgap reference voltage source with a general external large capacitor:

(1) It is necessary to add a large capacitor outside the chip, which adds a capacitor cost to the whole solution, and needs to increase the area of a capacitor on the printed circuit board PCB (Printed circuit board). At the same time, the external capacitor requires one more chip pin on the chip, which increases the cost of a bonding wire to the chip.

(2) Since there are many RF modules that need to use a low-noise bandgap reference voltage source in the RF chip, but the bandgap reference voltage source can only be connected with an off-chip capacitor, all RF modules that need to use a low-noise bandgap reference voltage source The modules must share a low noise bandgap reference.

(3) The external capacitance of the bandgap reference voltage source will cause the problem that the start-up time of the bandgap reference voltage source is too long, which will bring the overhead of the entire system startup time.

Contents of the invention

The embodiment of the present invention provides a low-noise bandgap reference voltage source.

An embodiment of the present invention provides a circuit for providing a bandgap reference voltage source, including a current-type bandgap reference voltage source, a first resistor, and a low-pass filter;

The current-mode bandgap reference voltage source is used to output a current with a temperature coefficient;

One end of the first resistor is connected to the output end of the current-mode bandgap reference voltage source, and the other end is grounded, and the first resistor is used to convert the current with temperature coefficient into a bandgap reference voltage with zero temperature coefficient;

The low-pass filter is used to convert the zero-temperature-coefficient bandgap reference voltage into a low-noise bandgap reference voltage output.

The above-mentioned circuit also includes that the low-pass filter includes a first PMOS transistor, a second PMOS transistor, and a first capacitor;

The source of the first PMOS transistor is connected to the non-ground terminal of the first resistor, the drain is connected to the output terminal of the low-pass filter, and the substrate is grounded;

The source of the second PMOS transistor is connected to the non-ground terminal of the first resistor, and the drain is connected to the output end of the low-pass filter. When the current-mode bandgap reference voltage source is started, the second PMOS transistor turn on, and turn off after the current-mode bandgap reference voltage source is started;

One end of the first capacitor is connected to the output end of the low-pass filter, and the other end is grounded.

The above circuit further includes a quick start circuit, the quick start circuit is used to convert the external enable signal of the current-mode bandgap reference voltage source into a quick start signal and output it to the substrate of the second PMOS transistor.

The above circuit also includes that the quick start circuit includes a first NOT gate, a second NOT gate, a third NOT gate, a fourth NOT gate, a second resistor, a second capacitor, and a NOR gate;

The first NOT gate and the second NOT gate are connected in sequence;

One end of the second resistor is connected to the output end of the second NOT gate, and one end is connected to the input end of the third NOT gate;

One end of the second capacitor is connected to the input end of the third NOT gate, and one end is grounded;

The third NOT gate and the fourth NOT gate are connected in sequence;

The input terminals of the NOR gate are respectively connected to the output terminals of the first NOT gate and the fourth NOT gate, and the NOR gate outputs the quick start signal.

The above-mentioned circuit also includes that the current-type bandgap reference voltage source includes a first transistor (214), a second transistor (215), a third resistor (201), a fourth resistor (205), a fifth resistor Resistor (206), operational amplifier (207), third PMOS transistor (208), fourth PMOS transistor (209), fifth PMOS transistor (210), sixth PMOS transistor (211), seventh PMOS transistor (214) , the eighth PMOS transistor (215), the first NMOS transistor, the second NMOS transistor, and at least one output branch;

Both the gates of the third PMOS transistor and the fifth PMOS transistor are connected to the output terminal of the operational amplifier, and the sources are both input with an operating voltage;

The source of the fourth PMOS transistor is connected to the drain of the third PMOS transistor, the gate is connected to the gate of the sixth PMOS transistor, and the drain is connected to the negative input terminal of the operational amplifier;

The source of the sixth PMOS transistor is connected to the drain of the fifth PMOS transistor, and the drain is connected to the positive input terminal of the operational amplifier;

The emitter of the first triode is connected to the negative input terminal of the operational amplifier, and the base and collector are grounded;

The emitter of the second triode is connected to the positive input terminal of the operational amplifier through the third resistor, and the base and collector are grounded;

The ratio of the area of the first triode to the area of the second triode is 1:n, where n is a positive integer;

One end of the fourth resistor is connected to the negative input end of the operational amplifier, and the other end is grounded;

One end of the fifth resistor is connected to the positive input end of the operational amplifier, and the other end is grounded;

The gate of the seventh PMOS transistor is connected to the gate of the fifth PMOS transistor, the input terminal of the output branch, the source is input with an operating voltage, and the drain is connected to the drain of the first NMOS transistor;

The gate of the eighth PMOS transistor is connected to the gate of the sixth PMOS transistor, the input terminal of the output branch, the source is input with an operating voltage, and the drain is connected to the drain of the second NMOS transistor;

The gate of the first NMOS transistor is connected to the drain, and the source is grounded;

The gate of the second NMOS transistor is connected to the gate of the first NMOS transistor, and the source is grounded;

The output branch outputs the current with a temperature coefficient.

The above circuit further includes that the output branch includes a first branch PMOS transistor (212) and a second branch PMOS transistor (213);

The source of the first branch PMOS transistor inputs an operating voltage, the gate is connected to the gate of the seventh PMOS transistor, and the drain is connected to the source of the second branch PMOS transistor;

The gate of the second branch PMOS transistor is connected to the gate of the eighth PMOS transistor, and the drain outputs the current with a temperature coefficient.

The above-mentioned circuit also includes that the current-type bandgap reference voltage source includes two or more output branches, and the currents with temperature coefficients output by the output branches are isolated from each other, and all pass through the first resistor, the The low-pass filter described above translates to a low-noise bandgap reference voltage output.

The above-mentioned circuit also includes that the resistance value of the first resistor is adjustable, and the circuit outputs low-noise bandgap reference voltage sources with different voltage values.

The above-mentioned circuit also includes that the circuit is used to provide a low-noise bandgap reference voltage source for a voltage-controlled oscillator in a radio frequency chip, a digital temperature-compensated crystal oscillator or one or more modules in a phase-locked loop.

The beneficial effects of the circuit for providing a bandgap reference voltage source provided by the embodiment of the present invention are: no need to add a large capacitor outside the chip, saving costs; providing multiple low-noise bandgap reference voltage sources, and by adding a quick start circuit Make the whole circuit start up fast.

Description of drawings

Fig. 1 is a schematic block diagram of a low-noise bandgap reference voltage source provided by an embodiment of the present invention;

Fig. 2 is the functional block diagram of current-mode bandgap reference voltage source Bandgap in accompanying drawing 1 that the embodiment of the present invention provides;

Fig. 3 is another kind of functional block diagram of the current-mode bandgap reference voltage source Bandgap in the accompanying drawing 1 that the embodiment of the present invention provides;

Fig. 4 is a kind of quick start logic provided by the embodiment of the present invention;

FIG. 5 is a quick start logic input and output waveform provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and beneficial effect of the invention clearer, the specific implementation manner of the invention will be described in detail below in conjunction with the accompanying drawings.

The RF chip low-noise bandgap reference voltage source solution on the SIM card chip provided by the present invention is as follows:

(1) Design a current-mode bandgap reference voltage source. The bandgap reference voltage source provides multiple currents with a slight temperature coefficient. The temperature coefficient of the current just offsets the temperature coefficient of the resistance used in the reference voltage source. A zero-temperature bandgap voltage reference is generated by passing current through a resistor.

(2) A low-pass filter with a very low cut-off frequency is connected behind the bandgap reference voltage source to filter out the noise of the bandgap reference voltage source.

(3) Design a quick start circuit for the bandgap reference voltage source, so that the bandgap reference voltage source can be quickly established.

(4) Different modules in the RF chip on the SIM card of the mobile phone provide different currents, and the low-noise bandgap reference voltage source is obtained through the same filtering method.

(5) Obtain bandgap reference voltage sources with different voltage values by adjusting the resistance.

A low-noise bandgap reference voltage source provided by the present invention will be described in detail below with specific embodiments.

Figure 1 is a block diagram of a low-noise bandgap reference voltage source.

Bandgap (104) is a current-type bandgap reference voltage source, and the output of Bandgap is a current with a slight temperature coefficient. The temperature coefficient of the current just offsets the temperature coefficient of the resistor R3 (103) used in the reference voltage source. A bandgap reference voltage source with zero temperature coefficient is generated by current flowing through resistor R3 (103). MP1 (101) is a PMOS tube (positiveMOS) with an on-resistance of about 10 MΩ, PMOS tube MP2 (105) is a switch tube, one end of the resistor R3 (103) is grounded, and the other end is connected to the output of the current-mode bandgap reference voltage source Bandgap ( 104) is connected to one end of the PMOS transistor MP1 (101). When the Bandgap (104) starts, the PMOS transistor MP2 (105) is turned on, and the current passes through the MP2 (105) to charge the capacitor C1 (102) to the voltage value of the reference voltage Vref. After starting, MP2 (105) is turned off, and the Vref voltage charges C11 (102) through the RC low-pass filter network composed of PMOS transistor MP1 (101) and capacitor C1 (102), assuming Rdson (MP1)=10Mohm ( Ohm), C1=20pF (method), the cut-off frequency of the RC low-pass filter network is w=1/(2πRC)=800Hz, so the filter network composed of this can reduce the noise greater than 800Hz frequency, if you need to lower the frequency To reduce the noise, it is necessary to design a filter network with a lower cut-off frequency, which can be realized by adjusting the values of the relevant resistor R and capacitor C by those skilled in the art. The noise generated by Vref is filtered out by an RC low-pass filter network to obtain a low-noise bandgap reference voltage source.

A circuit for providing a bandgap reference voltage source, which includes a current-mode bandgap reference voltage source, a first resistor, and a low-pass filter; the current-mode bandgap reference voltage source is used to output a current with a temperature coefficient; one end of the first resistor Connect the output end of the current-mode bandgap reference voltage source, the other end is grounded, and the first resistor is used to convert the current with temperature coefficient into a bandgap reference voltage with zero temperature coefficient;

A low-pass filter is used to convert the zero-temperature-coefficient bandgap reference to a low-noise bandgap output. The low-pass filter includes a first PMOS transistor, a second PMOS transistor, and a first capacitor; the source of the first PMOS transistor is connected to the non-ground terminal of the first resistor, the drain is connected to the output end of the low-pass filter, and the substrate is grounded; The source of the second PMOS tube is connected to the non-ground terminal of the first resistor, and the drain is connected to the output terminal of the low-pass filter. The second PMOS tube is turned on when the current-mode bandgap reference voltage source is started, and Close after completion; one end of the first capacitor is connected to the output end of the low-pass filter, and the other end is grounded.

The circuit also includes a quick start circuit, which is used to convert the external enable signal of the current-mode bandgap reference voltage source into a quick start signal and output it to the substrate of the second PMOS transistor.

Fig. 2 is a functional block diagram of the current-mode bandgap reference voltage source Bandgap in Fig. 1 . The input voltage of the voltage source is VDD (203), and the ground terminal is GND (204). The ratio of the area of the transistor Q1 ( 214 ) to the area of the transistor Q2 ( 215 ) is 1:n, where n is a positive integer. In the bandgap reference voltage source, n is generally 8 or 24. The Vx node forms a positive feedback loop through the operational amplifier OP (207), the PMOS tube PM2 (208), and the PMOS tube PM3 (209). Vy passes through the OP (207), the PMOS tube PM1 (210), and the PMOS tube PM4 (211 ) form a negative feedback loop, the negative feedback coefficient of the negative feedback loop is greater than the feedback coefficient of the positive feedback loop, so that the feedback of the entire bandgap reference voltage source circuit shows negative feedback, and Vx and Vy are clamped equal through negative feedback . The voltage at point Vx is Vbe, the voltage across R1 is ΔVbe, the current flowing through PM1 (210) and PM2 (208) is equal to I, because R2 (205)=R3 (206), so the current I=ΔVbe/ R1+Vbe/R2, ΔVbe/R1 is the current with positive temperature coefficient, Vbe/R2 is the current with negative temperature coefficient, adjust the resistance value of resistor R1 (201) and resistor R2 (205), you can get IB_VREF with a slight temperature coefficient (202) Current, such as IB1_VREF (202), IB2_VREF, IB3_VREF, IB4_VREF. As shown in Figure 1, the IB_VREF current with a slight temperature coefficient flows through the resistor R3 (206), generating Vref with zero temperature coefficient, Vref=(ΔVbe/R1+Vbe/R2)*R3, the value of R3 can be set arbitrarily to obtain the desired To get the desired Vref voltage, just ensure that the PMOS tube of the current mirror works in the saturation region. If multiple different low-noise reference voltage sources are required, multiple voltage sources can be mirrored by means of current mirroring to generate multiple bandgap reference currents with a slight temperature coefficient, and the current can be well isolated , reducing the mutual interference between the reference voltage sources, and then generating low-noise reference voltage sources that do not interfere with each other through the mirror circuit.

The current-mode bandgap reference voltage source includes a first triode (214), a second triode (215), a third resistor (201), a fourth resistor (205), a fifth resistor (206), an operational amplifier ( 207), the third PMOS tube (208), the fourth PMOS tube (209), the fifth PMOS tube (210), the sixth PMOS tube (211), the seventh PMOS tube (214), the eighth PMOS tube (215) , the first NMOS tube, the second NMOS tube, at least one output branch; the gates of the third PMOS tube and the fifth PMOS tube are connected to the output terminal of the operational amplifier, and the sources are all input with the operating voltage; the source of the fourth PMOS tube The pole is connected to the drain of the third PMOS transistor, the gate is connected to the gate of the sixth PMOS transistor, and the drain is connected to the negative input terminal of the operational amplifier; the source of the sixth PMOS transistor is connected to the drain of the fifth PMOS transistor, and the drain is connected to the drain of the fifth PMOS transistor. The positive input terminal of the operational amplifier is connected; the emitter of the first triode is connected with the negative input terminal of the operational amplifier, and the base and collector are grounded; the emitter of the second triode is connected with the positive input terminal of the operational amplifier through the third resistor , the base and the collector are grounded; the ratio of the area of the first triode to the area of the second triode is 1:n, where n is a positive integer; one end of the fourth resistor is connected to the negative input terminal of the operational amplifier, and the other end is grounded; One end of the fifth resistor is connected to the positive input terminal of the operational amplifier, and the other end is grounded; the gate of the seventh PMOS transistor is connected to the gate of the fifth PMOS transistor, the input terminal of the output branch, the source is input to the operating voltage, and the drain is connected to the drain of the first NMOS transistor. pole; the gate of the eighth PMOS transistor is connected to the gate of the sixth PMOS transistor, the input terminal of the output branch, the source inputs the operating voltage, and the drain is connected to the drain of the second NMOS transistor; the gate of the first NMOS transistor is connected to the drain, and the source The electrode is grounded; the gate of the second NMOS transistor is connected to the gate of the first NMOS transistor, and the source is grounded; the output branch outputs a current with a temperature coefficient.

The output branch includes a first branch PMOS transistor (212) and a second branch PMOS transistor (213); the source of the first branch PMOS transistor inputs the operating voltage, the gate is connected to the gate of the seventh PMOS transistor, and the drain is connected to The source of the second branch PMOS transistor; the gate of the second branch PMOS transistor is connected to the gate of the eighth PMOS transistor, and the drain outputs a current with a temperature coefficient.

The current-type bandgap reference voltage source includes two or more output branches, and the currents with temperature coefficients output by the output branches are isolated from each other, and are converted into low-noise bandgap references through the first resistor and the low-pass filter. voltage output. The resistance value of the first resistor is adjustable, and the circuit outputs low-noise bandgap reference voltage sources with different voltage values. The circuit is used to provide a low-noise bandgap reference voltage source for a voltage-controlled oscillator in a radio frequency chip, a digital temperature-compensated crystal oscillator or one or more modules in a phase-locked loop.

The schematic block diagram of the single-channel low-noise reference voltage source is shown in Figure 3, the input voltage of the voltage source is VDD (303), the ground terminal is GND (304), the function of the resistor R1 is the same as that in Figure 2, and will not be repeated here. , the output reference power supply is IB_VREF (302).

Figure 4 shows the quick start logic.

BG_EN is the enable signal of the low-noise bandgap reference voltage source. When BG_EN is low, the low-noise bandgap reference voltage source circuit is turned off. When BG_EN is high, the low-noise bandgap voltage reference source is turned on. The low-noise bandgap reference voltage source is turned off to on is the process of BG_EN changing from low to high. When BG_EN changes from low to high, BG_EN will delay about 54us through the delay unit composed of resistor R1 and capacitor C1. Different delays can be obtained by adjusting the value of resistor R1 and capacitor C1, and then react with BG_EN Perform phase-NOR to the signal to get the Fast_Setup signal. Fast_Setup is a narrow pulse signal. When BG_EN maintains a constant voltage, the Fast_Setup position is high and turns off the PMOSMP2 tube in Figure 1. When BG_EN changes from low to high, Fast_Setup generates a low voltage pulse of about 4us, which briefly turns on the PMOS transistor MP24us and then turns off.

The quick start circuit is used to convert the external enabling signal of the current-mode bandgap reference voltage source into a quick start signal and output it to the substrate of the second PMOS transistor.

The quick-start circuit comprises a first NOT gate, a second NOT gate, a third NOT gate, a fourth NOT gate, a second resistor, a second capacitor, and a NOR gate; the first NOT gate and the second NOT gate are connected in sequence; the second NOT gate One end of the resistor is connected to the output terminal of the second NOT gate, and one end is connected to the input terminal of the third NOT gate; one end of the second capacitor is connected to the input terminal of the third NOT gate, and one end is grounded; the third NOT gate and the fourth NOT gate are connected in sequence; The input terminals are respectively connected to the output terminal of the first NOT gate and the output terminal of the fourth NOT gate, and the NOR gate outputs a quick start signal.

FIG. 5 is a quick start logic input and output waveform, which is used to further illustrate the present invention.

When BG_EN remains low for a long time, Fast_Setup is high. When BG_EN is high for a long time, Fast_Setup is also high. Only when BG_EN changes from low to high, Fast_Setup will generate a pulse of about 4us.

In RFIC, the noise index of the reference voltage source is very high, and the isolation of the reference voltage source is also required to be high. The present invention is suitable for voltage-controlled oscillator VCO, digital temperature-compensated crystal oscillator DCXO, and phase-locked in RFIC. Ring PLL (PhaseLockedLoop) and other modules provide low-noise reference voltage sources.

To sum up, the embodiment of the present invention provides a circuit implementation structure of a low-noise bandgap reference voltage source; a circuit implementation structure of a current-type bandgap reference voltage source; an implementation structure and control method of a quick start logic; An isolation method for multiple reference voltages;

The above is a detailed introduction to a low-noise bandgap reference voltage source provided by the embodiment of the present invention. In this paper, a specific example is used to illustrate the principle and implementation of the present invention. The description of the above embodiment is only used to help understanding The method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be construed as a limitation of the invention.

Claims (8)

1. for providing a circuit for bandgap voltage reference, it is characterized in that: comprise current-type band gap reference voltage source, the first resistance, low-pass filter;

Described current-type band gap reference voltage source is for exporting the electric current of band temperature coefficient;

Described first resistance one end connects the output terminal of described current-type band gap reference voltage source, other end ground connection, and it is the bandgap voltage reference of zero-temperature coefficient that described first resistance is used for the current conversion of described band temperature coefficient;

Described low-pass filter is used for the bandgap voltage reference of described zero-temperature coefficient being converted into low noise bandgap references voltage and exports;

Described low-pass filter comprises the first PMOS, the second PMOS, the first electric capacity;

Described first PMOS source electrode is connected with the ungrounded end of described first resistance, and drain electrode is connected with described low-pass filter output terminal, grounded-grid;

Described second PMOS source electrode is connected with the ungrounded end of described first resistance, drain electrode is connected with described low-pass filter output terminal, described second PMOS is opened when described current-type band gap reference voltage source starts, and closes after described current-type band gap reference voltage source starts;

Described first electric capacity one end is connected with described low-pass filter output terminal, other end ground connection.

2. according to claim 1 for providing the circuit of bandgap voltage reference, it is characterized in that, this circuit also comprises fast start circuit, and described fast start circuit is used for the outside enable signal of described current-type band gap reference voltage source to be converted into the grid that quick enabling signal exports described second PMOS to.

3. according to claim 2ly it is characterized in that for providing the circuit of bandgap voltage reference, described fast start circuit comprises the first not gate, the second not gate, the 3rd not gate, the 4th not gate, the second resistance, the second electric capacity, rejection gate;

Described first not gate, the second not gate connect successively;

Described second resistance one end connects described second non-gate output terminal, and one end connects described 3rd not gate input end;

Described second electric capacity one end connects described 3rd not gate input end, one end ground connection;

Described 3rd not gate, the 4th not gate connect successively;

The input end of described rejection gate connects the output terminal of described first not gate, the output terminal of described 4th not gate respectively, and described rejection gate exports described quick enabling signal.

4. according to claim 1 for providing the circuit of bandgap voltage reference, it is characterized in that, described current-type band gap reference voltage source comprises the first triode (214), second triode (215), 3rd resistance (201), 4th resistance (205), 5th resistance (206), operational amplifier (207), 3rd PMOS (208), 4th PMOS (209), 5th PMOS (210), 6th PMOS (211), 7th PMOS (214), 8th PMOS (215), first NMOS tube, second NMOS tube, at least one exports branch road,

Described 3rd PMOS, the 5th PMOS grid are all connected with described operational amplifier output terminal, the equal input service voltage of source electrode;

Described 4th PMOS source electrode drains with described 3rd PMOS and is connected, and grid is connected with described 6th PMOS grid, drains to be connected with described operational amplifier negative input;

Described 6th PMOS source electrode drains with described 5th PMOS and is connected, and drains to be connected with described operational amplifier positive input;

Described first transistor emitter is connected with described operational amplifier negative input, base stage, grounded collector;

Described second transistor emitter is connected with described operational amplifier positive input by described 3rd resistance, base stage, grounded collector;

The area of described first triode and the area ratio of described second triode are 1:n, n is positive integer;

Described 4th resistance one end connects described operational amplifier negative input, other end ground connection;

Described 5th resistance one end connects described operational amplifier positive input, other end ground connection;

Described 7th PMOS grid connects described 5th PMOS grid, described output branch input, source electrode input service voltage, and drain electrode connects described first NMOS tube drain electrode;

Described 8th PMOS grid connects described 6th PMOS grid, described output branch input, source electrode input service voltage, and drain electrode connects described second NMOS tube drain electrode;

Described first NMOS tube grid is connected with drain electrode, source ground;

Described second NMOS tube grid is connected with described first NMOS tube grid, source ground;

Described output branch road exports the electric current of described band temperature coefficient.

5. according to claim 4ly it is characterized in that for providing the circuit of bandgap voltage reference, described output branch road comprises the first branch road PMOS (212), the second branch road PMOS (213);

Described first branch road PMOS source electrode input service voltage, grid is connected with described 7th PMOS grid, and drain electrode connects the source electrode of described second branch road PMOS;

The grid of described second branch road PMOS connects described 8th PMOS grid, and drain electrode exports the electric current of described band temperature coefficient.

6. according to claim 4 for providing the circuit of bandgap voltage reference, it is characterized in that: described current-type band gap reference voltage source comprises two or more and exports branch road, the electric current of the band temperature coefficient that described output branch road exports is mutually isolated, is all converted into low noise bandgap references voltage exports through described first resistance, described low-pass filter.

7. the circuit for providing bandgap voltage reference according to any one of claim 1-6, is characterized in that: described first resistance is adjustable, and described circuit exports the low-noise band-gap reference voltage source of different magnitude of voltage.

8. the circuit for providing bandgap voltage reference according to any one of claim 1-6, it is characterized in that: described circuit is used for for the voltage controlled oscillator in radio frequency chip, the one or more modules in digital compensation crystal oscillator or phaselocked loop provide low-noise band-gap reference voltage source.