CN117251020B - High-precision zero-temperature-drift reference voltage circuit - Google Patents

High-precision zero-temperature-drift reference voltage circuit Download PDF

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Publication number
CN117251020B
CN117251020B CN202311543438.XA CN202311543438A CN117251020B CN 117251020 B CN117251020 B CN 117251020B CN 202311543438 A CN202311543438 A CN 202311543438A CN 117251020 B CN117251020 B CN 117251020B
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switch
circuit
twenty
resistor
current
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CN117251020A (en
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Suzhou Baker Microelectronics Co Ltd
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Suzhou Baker Microelectronics Co Ltd
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
    • G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
    • G05F1/567—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for temperature compensation

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Amplifiers (AREA)

Abstract

The invention relates to the technical field of battery power supply, and discloses a high-precision zero-temperature-drift reference voltage circuit, which comprises: the power supply comprises a regulating circuit, an output circuit and a current source circuit, wherein the current source circuit is connected with the regulating circuit and an external power supply and is used for outputting a pull-down current when the external power supply is electrified; a regulating circuit connected to the output circuit; the regulating circuit changes the switch state based on the pull-down current, so that the output circuit outputs stable output current by continuously regulating the internal voltage difference of the regulating circuit after the output circuit changes the switch state and outputs the first initial current; when the output circuit outputs stable output current and the temperature changes, the output circuit outputs zero temperature drift reference voltage based on the temperature parameter and the internal pressure difference of the output circuit. The circuit can output high-precision zero temperature drift voltage which is not affected by temperature when the working temperature of the circuit changes, and improves the precision and reliability of a reference voltage circuit.

Description

High-precision zero-temperature-drift reference voltage circuit
Technical Field
The invention relates to the technical field of battery power supply, in particular to a high-precision zero-temperature-drift reference voltage circuit.
Background
At present, a reference voltage circuit is generally required to provide a reference voltage signal in a power control chip of a battery charging circuit, but the reference voltage circuit in the related art is generally greatly affected by temperature, so that the temperature drift of the reference voltage circuit in the related art is larger and the precision is lower, thereby reducing the control precision of the power control chip of the battery charging circuit and affecting the safety and reliability of the battery charging circuit. Meanwhile, after the working temperature of the circuit is increased, the leakage condition of the device is increased, so that the condition that the current capacity of the reference voltage circuit is reduced or the accuracy of the output voltage is reduced is caused.
Disclosure of Invention
Therefore, the invention aims to solve the problems of larger temperature drift and lower precision of the reference voltage circuit in the prior art, thereby providing the reference voltage circuit with high precision and zero temperature drift.
In order to achieve the above purpose, the present invention provides the following technical solutions:
in a first aspect, the present invention provides a reference voltage circuit comprising: the power supply comprises a regulating circuit, an output circuit and a current source circuit, wherein the current source circuit is connected with the regulating circuit, the output circuit and an external power supply and is used for outputting a pull-down current when the external power supply is electrified; a regulating circuit connected to the output circuit; the regulating circuit changes the switch state based on the pull-down current, so that the output circuit outputs stable output current by continuously regulating the internal voltage difference of the regulating circuit after the output circuit changes the switch state and outputs the first initial current; when the output circuit outputs stable output current and the temperature changes, the output circuit outputs zero temperature drift reference voltage based on the temperature parameter and the internal pressure difference of the output circuit.
The reference voltage circuit provided by the invention has the advantages that the output voltage is related to the temperature parameter and the internal pressure difference of the output circuit; when the temperature rises, the temperature parameter increases, and the internal pressure difference of the output circuit decreases, so that the output voltage is unchanged; when the temperature decreases, the temperature parameter decreases, and the internal voltage difference of the output circuit increases, so the magnitude of the output voltage is unchanged. Namely, when the temperature changes, the reference voltage circuit can output the reference voltage with high precision and zero temperature drift which does not change along with the temperature, and the stability of the circuit is improved.
In an alternative embodiment, the conditioning circuit includes: the third switching circuit is connected with the current source circuit, the fourth switching circuit, the output circuit and the external power supply; a fourth switching circuit connected to the current source circuit and the output circuit; the third switching circuit and the fourth switching circuit switch the self-switching state based on the pull-down current, so that the output circuit outputs stable output current by continuously adjusting the internal differential pressure of the third switching circuit and the fourth switching circuit after the output circuit switches the switching state and outputs the first initial current; when the output circuit outputs stable output current and the temperature changes, the output circuit outputs zero temperature drift voltage based on the temperature parameter and the internal pressure difference of the output circuit.
In an alternative embodiment, the third switching circuit comprises: a thirteenth switch, a fourteenth switch, a fifteenth switch, a sixteenth switch, a seventeenth switch, an eighteenth switch and a nineteenth switch, wherein the first end of the thirteenth switch is connected with the first end of the fourteenth switch, the first end of the fifteenth switch, the first end of the sixteenth switch, the first end of the seventeenth switch, the current source circuit, the output circuit and the external power supply, the control end and the second end of the thirteenth switch are connected with the control end of the fourteenth switch, and the second end of the thirteenth switch is also connected with the current source circuit; a fourteenth switch, the second end of which is connected with the second end of the seventeenth switch, the first end of the eighteenth switch, the first end of the nineteenth switch and the output circuit; a fifteenth switch, the control end of which is connected with the control end of the sixteenth switch and the second end of the sixteenth switch, and the second end of which is connected with the control end of the seventeenth switch circuit and the fourth switch circuit; a sixteenth switch, the second end of which is also connected with the fourth switch circuit; an eighteenth switch, the control end of which is connected with the second end and the control end of the nineteenth switch, and the second end of which is also connected with the fourth switch circuit; and a nineteenth switch, the second end of which is connected with the output circuit.
In an alternative embodiment, the fourth circuit includes: the circuit comprises a twenty-first switch, a twenty-second switch, a twenty-third switch, a twenty-fourteenth switch, a twenty-fifth switch, a second resistor and a third resistor, wherein the first end of the twenty-first switch is connected with the second end of the fifteenth switch, the control end of the twenty-first switch is connected with the first end of the second resistor and the first end of the third resistor, the control end of the twenty-first switch is also connected with the control end of the twenty-first switch, and the second end of the twenty-first switch is connected with the first end of the twenty-fourth switch and an output circuit; a twenty-first switch, the first end of which is connected with the second end of the sixteenth switch, and the second end of which is connected with the first end of the twenty-fifth switch and the output circuit; a twenty-second switch, the first end of which is connected with the control end of the twenty-second switch and the second end of the third resistor, and the control end of which is also connected with the control end of the twenty-third switch, the control end of the twenty-fourth switch and the control end of the twenty-fifth switch; the second end of the switch is connected with the current source circuit, and the second end of the switch is also connected with the first end of the twenty-third switch, the second end of the twenty-fourth switch, the second end of the twenty-fifth switch and the output circuit and then grounded; a twenty-third switch, the second end of which is connected with the second end of the eighteenth switch; and the second end of the second resistor is connected with the output circuit.
In an alternative embodiment, the output circuit includes: a twenty-first switch, a twenty-seventh switch, a twenty-eighth switch, a twenty-ninth switch, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a first capacitor, wherein the first end of the twenty-first switch is connected with the first end of the seventeenth switch, the control end of the twenty-first switch is connected with the first end of the nineteenth switch, and the second end of the twenty-first switch is connected with the first end of the fourth resistor; the second end of the fourth resistor outputs voltage, and the second end of the fourth resistor is connected with the first end of the fifth resistor and the second end of the second resistor; a fifth resistor, the second end of which is connected with the first end of the twenty-seventh switch; the control end of the twenty-seventh switch is connected with the control end of the twenty-ninth switch and the first end of the sixth resistor, and the second end of the twenty-seventh switch is connected with the control end of the twenty-eighth switch and the second end of the sixth resistor; a twenty-eighth switch, the first end of which is connected with the second end of the nineteenth switch and the first end of the twenty-ninth switch, and the second end of which is connected with the second end of the twenty-first switch; a twenty-ninth switch having a second terminal connected to the second terminal of the twentieth switch; a first end of the seventh resistor is connected with a first end of the sixth resistor, and a second end of the seventh resistor is connected with a second end of the twenty-fifth switch and then grounded; and the first end of the first capacitor is connected with the second end of the twentieth switch, and the second end of the first capacitor is connected with the second end of the seventeenth switch.
In an alternative embodiment, the ratio of the number of the twenty-eighth switch to the twenty-ninth switch is X:1.
in an alternative embodiment, the first capacitor is used to compensate the circuit.
The reference voltage circuit provided by the invention has the advantages that the first capacitor is a compensation capacitor and is used for compensating the control loop.
In an alternative embodiment, the current source circuit includes: the first switch circuit is connected with an external power supply, the regulating circuit, the output circuit and the second switch circuit; a second switching circuit connected to the adjusting circuit and the output circuit; when the external power supply is electrified, the first switch circuit switches the switch state, and after the second switch circuit is conducted and outputs the second initial current, the second switch circuit outputs the pull-down current which changes along with the temperature by continuously adjusting the internal pressure difference of the first switch circuit based on the temperature parameter.
According to the reference voltage circuit, the magnitude of the pull-down current of the current source circuit is positively correlated with the temperature parameter, and the temperature parameter is increased along with the increase of the circuit temperature, so that the pull-down current of the current source circuit is correspondingly increased when the circuit temperature is increased, the high-temperature current capacity of the reference voltage circuit can be improved, and the problems of current capacity reduction and output voltage precision reduction caused by self-leakage of devices in the reference voltage circuit can be solved when the working temperature of the reference voltage circuit is increased, so that the precision and reliability of the reference voltage circuit are further improved.
In an alternative embodiment, the first switching circuit includes: the switching device comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a first resistor, wherein the first end of the first switch is connected with the first end of the second switch, the first end of the fifth switch, the first end of the first resistor and an external power supply, the control end of the first switch is connected with the second end of the first switch and the control end of the second switch, and the second end of the first switch is also connected with the first end of the third switch; the second end of the second switch is connected with the control end of the fifth switch, the second end of the fifth switch and the control end of the sixth switch, and the second end of the second switch is also connected with the first end of the fourth switch; the control end of the third switch is connected with the control end of the fourth switch, and the second end of the third switch is connected with the second end of the fourth switch and the second switch circuit; the control end of the fourth switch is connected with the first end of the fourth switch; and the first end of the sixth switch is connected with the second end of the first resistor, and the second end of the sixth switch is connected with the second switch circuit.
In an alternative embodiment, the ratio of the number of the fifth switch to the number of the sixth switch is 1: n.
In an alternative embodiment, the second switching circuit comprises: a seventh switch, an eighth switch, a ninth switch, a tenth switch, an eleventh switch and a twelfth switch, wherein a first end of the seventh switch is connected with a control end and a first switch circuit, and a second end of the seventh switch is connected with a first end of the eighth switch; the control end of the eighth switch is connected with the second end of the seventh switch, and the second end of the eighth switch is connected with the first end of the ninth switch; a ninth switch, the control end of which is connected with the second end of the eighth switch, and the second end of which is connected with the first end of the tenth switch, the first end of the eleventh switch and the first end of the twelfth switch; a tenth switch, the control end of which is connected with the control end of the eleventh switch and the control end of the twelfth switch, and the second end of which is connected with the first switch circuit; an eleventh switch, the second end of which is connected with the control end and the first switch circuit; and a twelfth switch whose second terminal outputs the pull-down current.
In a second aspect, the present invention provides a power control chip, comprising: the reference voltage circuit of the first aspect is configured to output a zero temperature drift reference voltage.
When the temperature of the circuit changes, the power supply control chip provided by the invention has the advantages that the output voltage of the reference voltage circuit is related to the temperature parameter and the internal pressure difference of the output circuit; when the temperature rises, the temperature parameter increases, and meanwhile, the internal pressure difference of the output circuit decreases, so that the output voltage of the reference voltage circuit is unchanged; when the temperature is reduced, the temperature parameter is reduced, and the internal pressure difference of the output circuit is increased, so that the output voltage of the reference voltage circuit is unchanged. That is, when the temperature changes, the reference voltage circuit can output the reference voltage of high-precision zero temperature drift which does not change along with the temperature, thereby reducing the temperature drift of the power supply control chip and improving the precision of the power supply control chip.
In a third aspect, the present invention provides a battery charging circuit comprising: the power control chip of the second aspect is disposed in a power supply that can supply power to the battery without temperature variation.
According to the battery charging circuit provided by the invention, when the circuit temperature changes, the reference voltage circuit in the power supply control chip can output the reference voltage with high precision and zero temperature drift which does not change along with the temperature according to the temperature parameter and the internal pressure difference, so that the output of the power supply control chip is unchanged, the precision of the battery charging circuit is improved, the safety and the reliability of the battery charging circuit are ensured, a stable power supply is provided for a battery, and the service life of the battery is prolonged.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a composition diagram of one specific example of a reference voltage circuit according to an embodiment of the present invention;
fig. 2 is a composition diagram of another specific example of a reference voltage circuit according to an embodiment of the present invention;
FIG. 3 is a block diagram of one particular circuit of a reference voltage circuit according to an embodiment of the invention;
fig. 4 is a composition diagram of another specific example of a current source circuit according to an embodiment of the present invention;
fig. 5 is a block diagram of one specific circuit of the current source circuit according to the embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The present embodiment provides a reference voltage circuit, as shown in fig. 1, including: the power supply comprises a current source circuit 1, a regulating circuit 2 and an output circuit 3, wherein the current source circuit 1 is connected with the regulating circuit 2, the output circuit 3 and an external power supply and is used for outputting a pull-down current when the external power supply is electrified; a regulator circuit 2 connected to the output circuit 3; the regulating circuit 2 switches the switch state based on the pull-down current, so that the output circuit 3 outputs stable output current by continuously adjusting the internal pressure difference of the regulating circuit 2 after the output circuit 3 switches the switch state and outputs the first initial current; when the output circuit 3 outputs a stable output current, the output circuit 3 is caused to output a zero temperature drift reference voltage based on the temperature parameter and the internal pressure difference of the output circuit 3 when the temperature changes.
Specifically, as shown in fig. 1, when the external power supply is powered on, the current source circuit 1 outputs a pull-down current, the regulating circuit 2 switches itself and the switching state of the output circuit 3 based on the pull-down current, so that the output circuit 3 outputs a first initial current, and then the regulating circuit 2 continuously adjusts the internal pressure difference to make the output circuit 3 output a stable output current; since the magnitude of the temperature parameter is positively correlated with the temperature and the pressure difference inside the output circuit 3 is negatively correlated with the temperature, when the circuit temperature changes, the temperature parameter and the pressure difference inside the output circuit 3 change in opposite directions, so that the magnitude of the output voltage is unchanged.
According to the reference voltage circuit provided by the embodiment, when the temperature changes, the reference voltage with high precision and zero temperature drift which does not change along with the temperature can be output, and the stability of the circuit is improved.
In some alternative embodiments, as shown in fig. 2, the conditioning circuit includes: a third switching circuit 21 and a fourth switching circuit 22, wherein the third switching circuit 21 is connected with the current source circuit 1, the fourth switching circuit 22, the output circuit 3 and the external power supply; a fourth circuit 22 connected to the current source circuit 1 and the output circuit 3; the third switch circuit 21 and the fourth switch circuit 22 switch their own switch states based on the pull-down current, so that the output circuit 3 switches the switch states and outputs the first initial current, and then the output circuit 3 outputs a stable output current by continuously adjusting the internal voltage difference of the third switch circuit 21 and the fourth switch circuit 22; after the output circuit 3 outputs a stable output current, when the temperature changes, the output circuit is made to output a zero temperature drift voltage based on the temperature parameter and the internal pressure difference of the output circuit. The third switching circuit and the fourth switching circuit each include: a plurality of current mirror circuits.
Specifically, as shown in fig. 2, when the external power supply is powered on, the current source circuit 1 outputs a pull-down current, the third switch circuit 21 and the fourth switch circuit 22 switch the switch states of the output circuit 3 and themselves based on the pull-down current, so that the output circuit 3 outputs a first initial current, and then the output circuit 3 outputs a stable output current by continuously adjusting the internal voltage difference of the third switch circuit 21 and the fourth switch circuit 22; since the magnitude of the temperature parameter is positively correlated with the temperature and the pressure difference inside the output circuit 3 is negatively correlated with the temperature, when the circuit temperature changes, the temperature parameter and the pressure difference inside the output circuit 3 change in opposite directions, so that the magnitude of the output voltage is unchanged.
In some alternative embodiments, as shown in fig. 3, the third switching circuit 21 includes: thirteenth, fourteenth, fifteenth, sixteenth, seventeenth, eighteenth and nineteenth switches Q13, Q14, Q15, Q16, Q17, Q18, Q19.
As shown in fig. 3, the thirteenth switch Q13 has a first end connected to the first end of the fourteenth switch Q14, the first end of the fifteenth switch Q15, the first end of the sixteenth switch Q16, the first end of the seventeenth switch Q17, the current source circuit 1, the output circuit 3, and the external power source VIN, and has a control end and a second end connected to the control end of the fourteenth switch Q14, and a second end connected to the current source circuit 1; a fourteenth switch Q14 having a second terminal connected to the second terminal of the seventeenth switch Q17, the first terminal of the eighteenth switch Q18, the first terminal of the nineteenth switch Q19, and the output circuit 3; a fifteenth switch Q15 having a control terminal connected to the control terminal of the sixteenth switch Q16 and a second terminal of the sixteenth switch Q16, and a second terminal connected to the control terminal of the seventeenth switch Q17 and the fourth switch circuit 22; a sixteenth switch Q16, the second terminal of which is further connected to the fourth switch circuit 22; an eighteenth switch Q18 having a control terminal connected to the second terminal thereof and the control terminal of the nineteenth switch Q19, and a second terminal thereof further connected to the fourth switch circuit 22; the nineteenth switch Q19 has a second terminal connected to the output circuit 3.
As shown in fig. 3, the fourth circuit 22 includes: the twenty-first switch Q20, the twenty-first switch Q21, the twenty-second switch Q22, the twenty-third switch Q23, the twenty-fourth switch Q24, the twenty-fifth switch Q25, the second resistor R2, and the third resistor R3.
As shown in fig. 3, the twentieth switch Q20 has a first end connected to the second end of the fifteenth switch Q15, a control end connected to the first end of the second resistor R2 and the first end of the third resistor R3, a control end connected to the control end of the twenty-first switch Q21, and a second end connected to the first end of the twenty-fourth switch Q24 and the output circuit 3; a twenty-first switch Q21, a first end of which is connected to the second end of the sixteenth switch Q16, and a second end of which is connected to the first end of the twenty-fifth switch Q25 and the output circuit 3; a twenty-second switch Q22, the first end of which is connected to the control end thereof and the second end of the third resistor R3, and the control end of which is also connected to the control end of the twenty-third switch Q23, the control end of the twenty-fourth switch Q24 and the control end of the twenty-fifth switch Q25; the second end of the second switch is connected with the current source circuit 1, and the second end of the second switch is also connected with the first end of the twenty-third switch Q23, the second end of the twenty-fourth switch Q24, the second end of the twenty-fifth switch Q25 and the output circuit 3 and then grounded; a twenty-third switch Q23, a second terminal of which is connected to the second terminal of the eighteenth switch Q18; and a second end of the second resistor R2 is connected with the output circuit 3.
As shown in fig. 3, the output circuit 3 includes: twenty-sixth switch Q26, twenty-seventh switch Q27, twenty-eighth switch Q28, twenty-ninth switch Q29, fourth resistor R4, fifth resistor R5, sixth resistor R6, seventh resistor R7, and first capacitor C1.
As shown in fig. 3, a first end of the sixteenth switch Q26 is connected to the first end of the seventeenth switch Q17, a control end of the sixteenth switch Q26 is connected to the first end of the nineteenth switch Q19, and a second end of the sixteenth switch Q26 is connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 outputs the voltage VOUT, and the second end of the fourth resistor R4 is connected with the first end of the fifth resistor R5 and the second end of the second resistor R2; a fifth resistor R5 having a second terminal connected to the first terminal of the twenty-seventh switch Q27; the twenty-seventh switch Q27 has a control terminal connected to the control terminal of the twenty-ninth switch Q29 and the first terminal of the sixth resistor R6, and a second terminal connected to the control terminal of the twenty-eighth switch Q28 and the second terminal of the sixth resistor R6.
As shown in fig. 3, the twenty-eighth switch Q28 has a first terminal connected to the second terminal of the nineteenth switch Q19 and the first terminal of the twenty-ninth switch Q29, and a second terminal connected to the second terminal of the twenty-first switch Q21; a twenty-ninth switch Q29 having a second terminal connected to the second terminal of the twentieth switch Q20; a first end of the seventh resistor R7 is connected with the first end of the sixth resistor R6, and a second end of the seventh resistor R7 is connected with the second end of the twenty-fifth switch Q25 and then grounded; a first capacitor C1 has a first terminal connected to the second terminal of the twentieth switch Q20 and a second terminal connected to the second terminal of the seventeenth switch Q17.
As shown in fig. 3, the thirteenth switch Q13 to the twenty-fifth switch Q25 may each employ a corresponding MOS transistor or triode; the number ratio of the twenty-eighth switch Q28 to the twenty-ninth switch Q29 is X:1. after the external power source VIN is powered on, the current source circuit 1 generates a current i0, which is a pull-down current, the pull-down current i0 pulls down the voltages at the control terminals of the thirteenth switch Q13 and the fourteenth switch Q14, the thirteenth switch Q13 and the fourteenth switch Q14 are turned on, at this time, the voltage at the control terminal of the twenty-sixth switch Q26 is pulled up by the fourteenth switch Q14, the twenty-sixth switch Q26 is turned on, and therefore, the twenty-sixth switch Q26 pulls up the voltage at the first terminal of the twenty-seventh switch Q27 through the fourth resistor R4 and the fifth resistor R5, and the BE junction of the twenty-seventeenth switch Q27 is turned on.
As shown in fig. 3, when the twenty-seventh switch Q27 is turned on, an output current iout is generated in the branch circuit consisting of the twenty-sixth switch Q26, the fourth resistor R4, the fifth resistor R5, the twenty-seventh switch Q27, the sixth resistor R6 and the seventh resistor R7, and the output current iout pulls down the control terminal voltages of the twenty-eighth switch Q28 and the twenty-ninth switch Q29, and the twenty-eighth switch Q28 and the twenty-ninth switch Q29 are turned on; meanwhile, the twenty-sixth switch Q26 pulls up the control terminal voltages of the twenty-first switch Q20 and the twenty-first switch Q21 through the fourth resistor R4 and the second resistor R2, the twenty-first switch Q20 and the twenty-first switch Q21 are turned on, the twenty-sixth switch Q26 pulls up the control terminal voltages of the twenty-second switch Q22, the twenty-third switch Q23, the twenty-fourth switch Q24 and the twenty-fifth switch Q25 through the fourth resistor R4, the second resistor R2 and the third resistor R3, and the twenty-second switch Q22, the twenty-third switch Q23, the twenty-fourth switch Q24 and the twenty-fifth switch Q25 are turned on.
As shown in fig. 3, the twenty-third switch Q23 pulls down the control terminal voltages of the eighteenth switch Q18 and the nineteenth switch Q19, the eighteenth switch Q18 and the nineteenth switch Q19 are turned on, the twenty-fifth switch Q25 pulls down the control terminal voltage of the sixteenth switch Q16 through the twenty-first switch Q21, and the fifteenth switch Q15 and the sixteenth switch Q16 are turned on.
As shown in fig. 3, since the thirteenth switch Q13 and the fourteenth switch Q14 constitute a current mirror, the current flowing through the thirteenth switch Q13 and the fourteenth switch Q14 is a current i0, the current i0 flows into the current mirror constituted by the eighteenth switch Q18 and the nineteenth switch Q19, at this time, the current flowing through the eighteenth switch Q18 and the nineteenth switch Q19 is a first current i1, and since the eighteenth switch Q18 and the twenty third switch Q23 are connected in series, the current flowing through the twenty third switch Q23 is also the first current i1; meanwhile, since the twenty-second switch Q22, the twenty-third switch Q23, the twenty-fourth switch Q24, and the twenty-fifth switch Q25 constitute a current mirror structure, the currents flowing into the twenty-second switch Q22, into the twenty-third switch Q23, into the twenty-fourth switch Q24, and into the twenty-fifth switch Q25 are the first current i1.
As shown in fig. 3, since the fifteenth switch Q15 and the sixteenth switch Q16 constitute a current mirror structure, the current flowing out of the fifteenth switch Q15 and the current flowing out of the sixteenth switch Q16 are both the second current i2, and the first current i1 flowing out of the nineteenth switch Q19 flows into the twenty-eighth switch Q28 and the twenty-ninth switch Q29, respectively, forming the third current i3 flowing through the twenty-eighth switch Q28 and the fourth current i4 flowing through the twenty-ninth switch Q29.
As shown in fig. 3, when the external power supply VIN is just powered on, the output current iout is smaller, and the voltage across the sixth resistor R6 is smaller, so the voltages of the control terminals of the twenty-eighth switch Q28 and the twenty-ninth switch Q29 are almost equal, and since the first terminals of the twenty-eighth switch Q28 and the twenty-ninth switch Q29 are connected, the voltage differences between the first terminals and the control terminals of the twenty-eighth switch Q28 and the twenty-ninth switch Q29 are equal, and since the number ratio of the twenty-eighth switch Q28 and the twenty-ninth switch Q29 is X:1, therefore, the third current i3 flowing through the twenty-eighth switch Q28 is X times the fourth current i4 flowing through the twenty-ninth switch Q29.
As shown in fig. 3, when the external power supply VIN is just powered on, the current flowing from the fifteenth switch Q15 to the point B, the current flowing from the point B to the point D, and the current flowing from the sixteenth switch Q16 to the point C are both the second current i2, the current flowing from the point D to the twenty-fourth switch Q24 and the current flowing from the point C to the twenty-fifth switch Q25 are both the first current i1, the current flowing from the twenty-eighth switch Q28 to the point C is larger than the current flowing from the twenty-ninth switch Q29 to the point D, the voltage at the point C is larger than the voltage at the point D, the voltage at the second end of the twenty-first switch Q21 is larger than the voltage at the second end of the twenty-first switch Q20, and the voltage at the control end of the twenty-first switch Q21 is equal to the voltage at the control end of the twenty-first switch Q20, the current flowing from the point B to the twenty-fifth switch Q20 is larger than the current flowing from the twenty-eighth switch Q16 to the point C, the current flowing from the twenty-eighth switch Q21 is larger than the voltage at the point C, the sixteenth switch Q26 is also larger than the voltage at the sixteenth switch Q26, the twenty-fifth switch Q26 is turned on, and the current at the twenty-fifth switch Q26 is turned off is not increased, and the current at the twenty-fifth switch Q is turned on, and the current is turned off at the point Q15 is increased.
When the output current iout also increases, the voltage across the sixth resistor R6 increases, resulting in a voltage difference V between the first terminal and the control terminal of the twenty-eighth switch Q28 BE28 With respect to the voltage difference V between the first terminal and the control terminal of the twenty-ninth switch Q29 BE29 Smaller and smaller, V is the result of the exponential increase in current of the transistor with increasing voltage difference between the emitter and base BE28 And V is equal to BE29 The influence of the difference value between the two currents is gradually larger than the influence of the number ratio of the twenty-eighth switch Q28 and the twenty-ninth switch Q29 on the currents, namely, the fourth current i4 gradually increases relative to the third current i3, and the voltage at the point D gradually increases relative to the voltage at the point C, so that when the output current iout increases to a certain value, the fourth current i4 increases to be larger than the third current i3.
When the fourth current i4 increases to be greater than the third current i3, the voltage at the point D increases to be greater than the voltage at the point C, that is, at this time, the voltage difference between the control terminal and the second terminal of the twentieth switch Q20 is smaller than the voltage difference between the control terminal and the second terminal of the twenty-first switch Q21, so that the current flowing from the point B into the twentieth switch Q20 is smaller than the current flowing from the sixteenth switch Q16 into the twenty-first switch Q21, and the current flowing from the sixteenth switch Q16 into the twenty-first switch Q21 is equal to the current flowing from the fifteenth switch Q15 into the point B, and therefore, the voltage at the point B is pulled high, the seventeenth switch Q17 is turned off, the conduction margin of the twenty-sixth switch Q26 is reduced, the output current iout is reduced, and the fourth current i4 is reduced to be smaller than the third current i3.
From the above analysis, it follows that, when the circuit is in steady state, the third current i3 is equal to the fourth current i4, and is available from the circuit configuration shown in figure 3,
（4）
wherein V is BE29 For the voltage difference between the first terminal and the control terminal of the twenty-ninth switch Q29, V BE28 First of twenty-eighth switch Q28Voltage difference between terminal and control terminal, V R6 The voltage across the sixth resistor R6 IS the current at the second end of the twenty-ninth switch Q29, the current at the second end of the twenty-eighth switch Q28, the saturated current IS, the voltage equivalent of temperature VT, and the magnitude of VT increases with the temperature.
Since i3=ic28, i4=ic29 when the circuit reaches steady state, it is possible to
（5）
Therefore, the output reference voltage is
（6）
I.e.
（7）
Wherein V is BE27 The voltage difference between the first end and the control end of the twenty-seventh switch Q27 is reduced along with the temperature rise, VT is the voltage equivalent of the temperature, and the voltage equivalent of the temperature rises along with the temperature rise, so that after the parameters in the output reference voltage are matched and designed, when the temperature changes, VOUT is unchanged, and the output reference voltage with high precision and zero temperature drift is formed.
In some alternative embodiments, as shown in fig. 4, the current source circuit includes: a first switch circuit 11 and a second switch circuit 12, wherein the first switch circuit 11 is connected with an external power supply, the regulating circuit 2, the output circuit 3 and the second switch circuit 12; a second switching circuit 12 connected to the regulator circuit 2 and the output circuit 3; when the external power supply is powered on, the first switch circuit 11 switches the switch state, and the second switch circuit 12 switches the switch state and outputs a second initial current, and then based on the temperature parameter, the second switch circuit 12 outputs a pull-down current i0 changing with the temperature by continuously adjusting the internal pressure difference of the first switch circuit 11.
Specifically, as shown in fig. 4, when the external power supply is powered on, the first switch circuit 11 and the second switch circuit 12 switch states to output a second initial current; the magnitude of the pull-down current i0 is positively correlated with the temperature parameter, and the temperature parameter increases along with the temperature rise, so that when the circuit temperature rises, the pull-down current i0 also increases, thereby solving the problems of current capacity reduction and output voltage precision reduction caused by self-leakage of elements in the reference voltage circuit under the high temperature condition.
The current source circuit provided by the invention can improve the high-temperature current capability of the pull-down current i0, and when the current source circuit is used in a reference voltage circuit and the working temperature of the reference voltage circuit is increased, the current capability reduction caused by self-leakage of devices in the reference voltage circuit and the problem of reduction of the precision of output voltage can be solved, so that the precision and the reliability of the reference voltage circuit are further improved.
In some alternative embodiments, as shown in fig. 5, the first switching circuit 11 includes: the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6 and the first resistor R1.
As shown in fig. 5, a first end of the first switch Q1 is connected to a first end of the second switch Q2, a first end of the fifth switch Q5, a first end of the first resistor R1, the adjusting circuit, and the external power source VIN, a control end of the first switch Q1 is connected to a second end of the first switch Q2 and a control end of the second switch Q2, and a second end of the first switch Q3 is also connected to a first end of the third switch Q3; the second end of the second switch Q2 is connected with the control end of the fifth switch Q5, the second end of the fifth switch Q5 and the control end of the sixth switch Q6, and the second end of the second switch Q2 is also connected with the first end of the fourth switch Q4; the control end of the third switch Q3 is connected with the control end of the fourth switch Q4, and the second end of the third switch Q3 is connected with the second end of the fourth switch Q4 and the second switch circuit 12; a control end of the fourth switch Q4 is connected with the first end of the fourth switch Q4; the sixth switch Q6 has a first terminal connected to the second terminal of the first resistor R1 and a second terminal connected to the second switching circuit 12.
As shown in fig. 5, the second switching circuit includes: a seventh switch Q7, an eighth switch Q8, a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, and a twelfth switch Q12, wherein a first end of the seventh switch Q7 is connected to the control end and the first switch circuit 11, and a second end thereof is connected to the first end of the eighth switch Q8; an eighth switch Q8, a control terminal of which is connected to the second terminal of the seventh switch Q7, and a second terminal of which is connected to the first terminal of the ninth switch Q9; a control end of the ninth switch Q9 is connected to the second end of the eighth switch Q8, and the second end of the ninth switch Q9 is connected to the first end of the tenth switch Q10, the first end of the eleventh switch Q11, and the first end of the twelfth switch Q12; a tenth switch Q10 having a control terminal connected to the control terminal of the eleventh switch Q11 and the control terminal of the twelfth switch Q12, and a second terminal connected to the first switch circuit 11; an eleventh switch Q11, a second end of which is connected to the control end thereof and the first switch circuit 11; the twelfth switch Q12 has a second terminal outputting a pull-down current i0.
As shown in fig. 5, the first to fourth switches Q1 to Q4 and the seventh to twelfth switches Q7 to Q12 may each employ a corresponding MOS transistor or triode; the number ratio of the fifth switch Q5 to the sixth switch Q6 is 1: n. After the external power source VIN is powered on, since the first terminal of the fifth switch Q5 inputs a high voltage, the high voltage turns on the diode between the first terminal of the fifth switch Q5 and the control terminal of the fifth switch Q5, the diode between the control terminal of the fourth switch Q4 and the second terminal of the fourth switch Q4, the diode between the control terminal of the seventh switch Q7 and the second terminal of the seventh switch Q7, the diode between the control terminal of the eighth switch Q8 and the second terminal of the eighth switch Q8, and the diode between the control terminal of the ninth switch Q9 and the second terminal of the ninth switch Q9, and thus, a current is generated in each diode, and the control terminal voltage of the fifth switch Q5 is pulled down, and the fifth switch Q5 is turned on.
As shown in fig. 5, after the fifth switch Q5 is turned on, the control terminal voltages of the third switch Q3 and the fourth switch Q4 are pulled up through the fifth switch Q5, the third switch Q3 and the fourth switch Q4 are turned on, the control terminal voltage of the seventh switch Q7 is pulled up through the fourth switch Q4 and the fifth switch Q5, the seventh switch Q7 is turned on, and so on, the eighth switch Q8 and the ninth switch Q9 are turned on; at this time, the control terminal voltages of the first switch Q1 and the second switch Q2 are pulled down through the third switch Q3, the seventh switch Q7, the eighth switch Q8 and the ninth switch Q9, and the first switch Q1 and the second switch Q2 are turned on; and, the control terminal voltage of the sixth switch Q6 is pulled down through the fourth switch Q4, the seventh switch Q7, the eighth switch Q8 and the ninth switch Q9, and the sixth switch Q6 is turned on.
As shown in fig. 5, after the sixth switch Q6 is turned on, the control terminal voltages of the tenth, eleventh and twelfth switches Q10, Q11 and Q12 are pulled high through the sixth switch Q6 and the first resistor R1, and the tenth, eleventh and twelfth switches Q10, Q11 and Q12 are turned on.
As shown in fig. 5, when the external power supply VIN is just powered on, the currents flowing through the fifth switch Q5 and the sixth switch Q6 are smaller, and the voltages across the first resistor R1 are smaller, so the voltages at the first ends of the fifth switch Q5 and the sixth switch Q6 are almost equal, and therefore, the voltage differences between the first ends and the control ends of the fifth switch Q5 and the sixth switch Q6 are equal, and further, since the number ratio of the fifth switch Q5 to the sixth switch Q6 is 1: n, therefore, the sixth current i6 flowing through the sixth switch Q6 is N times the fifth current i5 flowing through the fifth switch Q5, that is, the current flowing from the sixth switch Q6 into the eleventh switch Q11 is greater than the current flowing from the fifth switch Q5 into the point a just before the external power source VIN is powered on.
As shown in fig. 5, since the tenth switch Q10, the eleventh switch Q11 and the twelfth switch Q12 constitute a current mirror structure, the current flowing from the point a into the tenth switch Q10 is equal to the current flowing from the sixth switch Q6 into the eleventh switch Q11, and since the first switch Q1 and the second switch Q2 constitute a current mirror structure, the third switch Q3 and the fourth switch Q4 constitute a current mirror structure, the current flowing from the second switch Q2 into the point a is equal to the current flowing from the point a into the fourth switch Q4, and thus, the current flowing from the fifth switch Q5 into the point a is smaller than the current flowing from the point a into the tenth switch Q10, and therefore, the point a is at a low level, the sixth current i6 flowing through the sixth switch Q6 and the fifth current i5 flowing through the fifth switch Q5 are continuously increased, and the voltage across the first resistor R1 is also continuously increased, thereby causing the voltage difference VBE6 between the first end of the sixth switch Q6 and the emitter of the control terminal to be gradually decreased relative to the voltage difference VBE5 between the first end of the fifth switch Q5 and the control terminal.
As shown in fig. 5, since the current of the triode increases exponentially with the voltage difference between the emitter and the control terminal, the influence of the difference between VBE5 and VBE6 on the current is gradually larger than the influence of the number ratio of the fifth switch Q5 and the sixth switch Q6 on the current, that is, the fifth current i5 gradually increases relative to the sixth current i6, when the voltage across the first resistor R1 increases to a certain value, the fifth current i5 increases to be larger than the sixth current i6, at this time, the voltage at the point a becomes high level, the fifth switch Q5 and the sixth switch Q6 gradually turn off, the fifth current i5 and the sixth current i6 gradually decrease, at this time, the voltage across the first resistor R1 also gradually decreases until the circuit state enters the next cycle after the fifth current i5 is smaller than the sixth current i6 until the circuit reaches a steady state.
Thus, as shown in fig. 5, after the circuit reaches steady state, the fifth current i5 is equal to the sixth current i6, at which point,
（1）
wherein V is BE5 V is the voltage difference between the first terminal and the control terminal of the fifth switch Q5 BE6 V is the voltage difference between the first end and the control end of the sixth switch Q6 R1 The voltage across the first resistor R1, the current at the second end of the fifth switch Q5, the current at the second end of the sixth switch Q6, the saturated current, the voltage equivalent, the temperature, and the voltage equivalent, the magnitude of which increases with the temperature rise, are given by IC5, IC 6. Since i5=ic5, i6=ic6 when the circuit reaches steady state, it is possible to
（2）
Finally, under the action of the current mirror structure formed by the tenth switch Q10, the eleventh switch Q11 and the twelfth switch Q12, the current flowing from the thirteenth switch Q13 into the twelfth switch Q12 is made to be
（3）
Therefore, when the working temperature of the circuit is increased, VT is increased along with the temperature increase, and the current i0 is also increased, so that the problems of current capacity reduction and output voltage precision reduction caused by the self-leakage of the element in the reference voltage circuit at high temperature are solved.
Note that, the seventh switch Q7, the eighth switch Q8, and the ninth switch Q9 are used to ensure that, after the circuit is started, the sum of the voltage between the first terminal and the control terminal of the fifth switch Q5, the voltage between the control terminal and the second terminal of the fourth switch Q4, the voltage between the control terminal and the second terminal of the seventh switch Q7, the voltage between the control terminal and the second terminal of the eighth switch Q8, and the voltage between the control terminal and the second terminal of the ninth switch Q9 is slightly larger than the start-up voltages of the regulating circuit 2 and the output circuit 3, and therefore, the number of specific series connection of the seventh switch Q7, the eighth switch Q8, and the ninth switch Q9 is set according to the start-up voltages required by the regulating circuit 2 and the output circuit 3, which is not limited.
The present embodiment provides a power control chip, including: the reference voltage circuit of any of the above embodiments and any optional implementation thereof, wherein the reference voltage circuit is configured to output a zero temperature drift voltage.
When the temperature of the circuit changes, the output voltage of the reference voltage circuit is unchanged, so that the temperature drift of the power supply control chip is reduced, and the accuracy of the power supply control chip is improved.
The present embodiment provides a battery charging circuit including: the power control chip of the above embodiment is disposed in a power supply that can provide a battery with power that does not change with temperature.
According to the battery charging circuit provided by the embodiment, when the circuit temperature changes, the output of the power supply control chip is unchanged, so that the accuracy of the battery charging circuit is improved, the safety and reliability of the battery charging circuit are ensured, a stable power supply is provided for a battery, and the service life of the battery is prolonged.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.

Claims (9)

1. A reference voltage circuit, comprising: a regulating circuit, an output circuit and a current source circuit, wherein,
the current source circuit is connected with the regulating circuit, the output circuit and the external power supply and is used for outputting pull-down current when the external power supply is electrified;
a regulating circuit connected to the output circuit;
the regulating circuit is used for switching the switch state based on the pull-down current, so that the output circuit outputs stable output current by continuously regulating the internal pressure difference of the regulating circuit after the output circuit is switched to the switch state and outputs first initial current;
when the output circuit outputs stable output current and the temperature changes, the output circuit outputs zero temperature drift reference voltage based on temperature parameters and internal pressure difference of the output circuit;
the regulating circuit includes: a third switching circuit and a fourth switching circuit, wherein,
the third switch circuit is connected with the current source circuit, the fourth switch circuit, the output circuit and the external power supply;
a fourth switching circuit connected to the current source circuit and the output circuit;
the third switch circuit and the fourth switch circuit switch the switch state of the output circuit based on the pull-down current, so that the output circuit outputs stable output current by continuously adjusting the internal voltage difference of the third switch circuit and the fourth switch circuit after the output circuit switches the switch state and outputs first initial current;
When the output circuit outputs stable output current and the temperature changes, the output circuit outputs zero temperature drift reference voltage based on temperature parameters and internal pressure difference of the output circuit;
the third switching circuit includes: thirteenth, fourteenth, fifteenth, sixteenth, seventeenth, eighteenth and nineteenth switches, wherein,
a thirteenth switch, a first end of which is connected with the first end of the fourteenth switch, the first end of the fifteenth switch, the first end of the sixteenth switch, the first end of the seventeenth switch, the current source circuit, the output circuit and an external power supply, a control end and a second end of which are connected with the control end of the fourteenth switch, and a second end of which is also connected with the current source circuit;
a fourteenth switch having a second terminal connected to the second terminal of the seventeenth switch, the first terminal of the eighteenth switch, the first terminal of the nineteenth switch, and the output circuit;
a fifteenth switch, a control end of which is connected with the control end of the sixteenth switch and a second end of the sixteenth switch, and a second end of which is connected with the control end of the seventeenth switch and the fourth switch circuit;
A sixteenth switch, the second end of which is also connected with the fourth switch circuit;
an eighteenth switch, the control end of which is connected with the second end of the eighteenth switch and the control end of the nineteenth switch, and the second end of which is also connected with the fourth switch circuit;
a nineteenth switch having a second end connected to the output circuit;
the fourth circuit includes: a twenty-first switch, a twenty-second switch, a twenty-third switch, a twenty-fourth switch, a twenty-fifth switch, a second resistor, and a third resistor, wherein,
a twenty-first switch, a control end of which is connected with the first end of the second resistor and the first end of the third resistor, a control end of which is also connected with the control end of the twenty-first switch, and a second end of which is connected with the first end of the twenty-fourth switch and the output circuit;
a twenty-first switch, a first end of which is connected with a second end of the sixteenth switch, and a second end of which is connected with a first end of the twenty-fifth switch and the output circuit;
a twenty-second switch, the first end of which is connected with the control end of the twenty-second switch and the second end of the third resistor, and the control end of which is also connected with the control end of the twenty-third switch, the control end of the twenty-fourth switch and the control end of the twenty-fifth switch; the second end of the second switch is connected with the current source circuit, and the second end of the second switch is also connected with the first end of the twenty-third switch, the second end of the twenty-fourth switch, the second end of the twenty-fifth switch and the output circuit and then grounded;
A twenty-third switch, a second end of which is connected with a second end of the eighteenth switch;
the second end of the second resistor is connected with the output circuit;
the output circuit includes: a twenty-first switch, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor, wherein,
a sixteenth switch, a first end of which is connected with the first end of the seventeenth switch, a control end of which is connected with the first end of the nineteenth switch, and a second end of which is connected with the first end of the fourth resistor;
the second end of the fourth resistor outputs voltage, and the second end of the fourth resistor is connected with the first end of the fifth resistor and the second end of the second resistor;
a fifth resistor, a second end of which is connected with the first end of the twenty-seventh switch;
a twenty-seventh switch, the control end of which is connected with the control end of the twenty-ninth switch and the first end of the sixth resistor, and the second end of which is connected with the control end of the twenty-eighth switch and the second end of the sixth resistor;
a twenty-eighth switch, a first end of which is connected with a second end of the nineteenth switch and a first end of the twenty-ninth switch, and a second end of which is connected with a second end of the twenty-first switch;
A twenty-ninth switch having a second terminal connected to the second terminal of the twenty-eighth switch;
and the first end of the seventh resistor is connected with the first end of the sixth resistor, and the second end of the seventh resistor is connected with the second end of the twenty-fifth switch and then grounded.
2. The reference voltage circuit of claim 1, wherein the reference voltage circuit comprises a reference voltage circuit,
the number ratio of the twenty-eighth switch to the twenty-ninth switch is X:1.
3. the reference voltage circuit of claim 2, further comprising: and the first end of the first capacitor is connected with the second end of the twenty-first switch, and the second end of the first capacitor is connected with the second end of the seventeenth switch and is used for compensating the circuit.
4. A reference voltage circuit according to any one of claims 1 to 3, wherein the current source circuit comprises: a first switch circuit and a second switch circuit, wherein,
the first switch circuit is connected with an external power supply, the regulating circuit, the output circuit and the second switch circuit;
a second switching circuit connected to the adjusting circuit and the output circuit;
when an external power supply is electrified, the first switch circuit switches the switch state, and after the second switch circuit switches the switch state and outputs a second initial current, the second switch circuit outputs a pull-down current changing along with the temperature by continuously adjusting the internal pressure difference of the first switch circuit based on the temperature parameter.
5. The reference voltage circuit of claim 4, wherein the first switching circuit comprises: a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a first resistor, wherein,
the first end of the first switch is connected with the first end of the second switch, the first end of the fifth switch, the first end of the first resistor, the regulating circuit and the external power supply, the control end of the first switch is connected with the second end of the first switch and the control end of the second switch, and the second end of the first switch is also connected with the first end of the third switch;
the second end of the second switch is connected with the control end of the fifth switch, the second end of the fifth switch and the control end of the sixth switch, and the second end of the second switch is also connected with the first end of the fourth switch;
the control end of the third switch is connected with the control end of the fourth switch, and the second end of the third switch is connected with the second end of the fourth switch and the second switch circuit;
the control end of the fourth switch is connected with the first end of the fourth switch;
and the first end of the sixth switch is connected with the second end of the first resistor, and the second end of the sixth switch is connected with the second switch circuit.
6. The reference voltage circuit of claim 5, wherein the reference voltage circuit comprises a reference voltage circuit,
The number ratio of the fifth switch to the sixth switch is 1: n.
7. The reference voltage circuit of claim 6, wherein the second switching circuit comprises: a seventh switch, an eighth switch, a ninth switch, a tenth switch, an eleventh switch and a twelfth switch, wherein,
a seventh switch, the first end of which is connected with the control end and the first switch circuit, and the second end of which is connected with the first end of the eighth switch;
an eighth switch, the control end of which is connected with the second end of the seventh switch, and the second end of which is connected with the first end of the ninth switch;
a ninth switch, the control end of which is connected with the second end of the eighth switch, and the second end of which is connected with the first end of the tenth switch, the first end of the eleventh switch and the first end of the twelfth switch;
a tenth switch, the control end of which is connected with the control end of the eleventh switch and the control end of the twelfth switch, and the second end of which is connected with the first switch circuit;
an eleventh switch, the second end of which is connected with the control end and the first switch circuit;
and a twelfth switch whose second terminal outputs the pull-down current.
8. A power control chip, comprising: the reference voltage circuit of any one of claims 1 to 7 for outputting a zero temperature drift reference voltage.
9. A battery charging circuit, comprising: the power control chip of claim 8, wherein the power control chip is disposed in a power supply that provides a temperature-invariant power supply to the battery.
CN202311543438.XA 2023-11-20 2023-11-20 High-precision zero-temperature-drift reference voltage circuit Active CN117251020B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5675243A (en) * 1995-05-31 1997-10-07 Motorola, Inc. Voltage source device for low-voltage operation
JP2009187430A (en) * 2008-02-08 2009-08-20 Asahi Kasei Toko Power Device Corp Regulator circuit
JP2010277479A (en) * 2009-05-29 2010-12-09 Toshiba Corp Power circuit
CN110865677A (en) * 2019-12-09 2020-03-06 北京集创北方科技股份有限公司 Reference source circuit, chip, power supply and electronic equipment
CN114115433A (en) * 2021-12-29 2022-03-01 苏州锴威特半导体股份有限公司 Band gap reference circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5675243A (en) * 1995-05-31 1997-10-07 Motorola, Inc. Voltage source device for low-voltage operation
JP2009187430A (en) * 2008-02-08 2009-08-20 Asahi Kasei Toko Power Device Corp Regulator circuit
JP2010277479A (en) * 2009-05-29 2010-12-09 Toshiba Corp Power circuit
CN110865677A (en) * 2019-12-09 2020-03-06 北京集创北方科技股份有限公司 Reference source circuit, chip, power supply and electronic equipment
CN114115433A (en) * 2021-12-29 2022-03-01 苏州锴威特半导体股份有限公司 Band gap reference circuit

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