CN217181449U - High-side constant current source current-sharing design circuit with low voltage drop, high precision and low ripple - Google Patents
High-side constant current source current-sharing design circuit with low voltage drop, high precision and low ripple Download PDFInfo
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- CN217181449U CN217181449U CN202220876474.2U CN202220876474U CN217181449U CN 217181449 U CN217181449 U CN 217181449U CN 202220876474 U CN202220876474 U CN 202220876474U CN 217181449 U CN217181449 U CN 217181449U
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Abstract
The utility model belongs to the technical field of the constant current source design, specifically disclose a high limit constant current source design circuit that flow equalizes of low pressure drop high accuracy low ripple, include: the current transformers comprise a plurality of constant current sources, operational amplifiers and digital-to-analog conversion circuit levels; the first input end of each constant current source after being connected in parallel is connected with an input voltage, the second input end of each constant current source is connected with the output end of the operational amplifier, the output end of each constant current source is connected with the negative input end of the operational amplifier after being connected with the current transformer in series, the input end of the digital-to-analog conversion circuit is connected with an input digital control signal, and the output end of the digital-to-analog conversion circuit is electrically connected with the positive input end of the operational amplifier. The digital control signal is converted into high-precision analog quantity through DA and then is subjected to PI proportional integration with a high-precision current transformer to obtain a loop error signal, and a constant current source at the lower end is driven. And the output end of the constant current source is connected to the negative input end of the high-precision operational amplifier through a current transformer for PI control. The circuit has a good current equalizing effect, meets the requirement of parallel connection of multiple modules, and is suitable for floating ground design.
Description
Technical Field
The utility model belongs to the technical field of the constant current source design, especially about a high limit constant current source design circuit that flow equalizes of low pressure drop high accuracy low ripple.
Background
At present, the design circuit scheme of the constant current source is mostly based on low-side current detection, namely, the scheme that one end of a current detection resistor is grounded is required, the low-side current detection scheme is influenced by the length, the connection reliability and the temperature characteristic of a combined bus in the application of large current and multiple Metal Oxide Semiconductors (MOS), and the current equalizing effect of the MOS tube is poor. In order to inhibit the influence of the internal resistance of the combined bus, the resistance value of the detection resistor is often selected to be large, and the requirement of high-current low-voltage-drop high-efficiency output cannot be met. Meanwhile, the low-side current detection scheme limits the floating requirement of the controller and the constant current source to a certain extent.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that the low side current detection scheme in the constant current source design has restricted the superficial ground demand of controller and constant current source to a certain extent.
The utility model provides a high limit constant current source design circuit that flow equalizes of low pressure drop high accuracy low ripple, the design circuit that flow equalizes includes: the current transformers comprise a plurality of constant current sources, operational amplifiers and digital-to-analog conversion circuit levels;
the first input end of each parallel constant current source is connected with an input voltage, the second input end of each parallel constant current source is connected with the output end of the operational amplifier, the output end of each parallel constant current source is connected with the negative input end of the operational amplifier after being connected with a current transformer in series, the input end of the digital-to-analog conversion circuit is connected with an input digital control signal, and the output end of the digital-to-analog conversion circuit is electrically connected with the positive input end of the operational amplifier.
Preferably, the current-sharing design circuit further comprises a voltage-stabilizing power supply, wherein the input end of the voltage-stabilizing power supply is connected with an input voltage, and the output end of the voltage-stabilizing power supply is connected with the input end of each of the parallel constant current sources.
Preferably, the constant current source comprises a driving operational amplifier U1A, an MOS (metal oxide semiconductor) tube and an amplifying current-sharing operational amplifier U1B, wherein a D stage of the MOS tube is connected with an input voltage, an S stage of the MOS tube is connected with a sampling resistor in series and then serves as an output end, and a G stage of the MOS tube is electrically connected with the output end of the driving operational amplifier U1A;
two ends of the sampling resistor are respectively connected with the positive input end and the negative input end of the amplification current-sharing operational amplifier U1B, the output end of the amplification current-sharing operational amplifier U1B is connected with the negative input end of the driving operational amplifier U1A, and the positive input end of the driving operational amplifier U1A is connected with an input digital control signal.
Preferably, the sampling resistor comprises two resistors connected in parallel.
Compared with the prior art, according to the utility model discloses a high limit constant current source design circuit that flow equalizes of low pressure drop high accuracy low ripple, include: the current transformers comprise a plurality of constant current sources, operational amplifiers and digital-to-analog conversion circuit levels; the first input end of each parallel constant current source is connected with an input voltage, the second input end of each parallel constant current source is connected with the output end of the operational amplifier, the output end of each parallel constant current source is connected with the negative input end of the operational amplifier after being connected with a current transformer in series, the input end of the digital-to-analog conversion circuit is connected with an input digital control signal, and the output end of the digital-to-analog conversion circuit is electrically connected with the positive input end of the operational amplifier. The digital control signal is given in advance through a digital code, and is converted into high-precision analog quantity through a DA (digital-to-analog) converter, and the analog quantity is compared with a high-precision current transformer and subjected to PI (proportional integral) to obtain a loop error signal so as to drive the constant current sources of the n sub-modules at the lower end. The constant current sources are connected in parallel. The input end of the constant current source is connected with a voltage stabilizing input Vi, and the output end of the constant current source outputs current and is connected to the negative input end of the high-precision operational amplifier through a current transformer for PI control. And the output end of the high-precision operational amplifier is connected. The good current equalizing effect meets the requirement of parallel connection of a plurality of modules; the method is not influenced by the requirement of customers on output grounding, and is suitable for floating ground design.
Drawings
FIG. 1 is a circuit diagram of the high-side constant current source with low voltage drop, high precision and low ripple of the present invention;
fig. 2 is a schematic diagram of the design of the constant current source circuit of the present invention.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited by the following detailed description.
Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
As shown in fig. 1 and fig. 2, the embodiment of the utility model provides a high limit constant current source design circuit that flow equalizes of low pressure drop high accuracy low ripple, the design circuit that flow equalizes includes: the current transformers comprise a plurality of constant current sources, operational amplifiers and digital-to-analog conversion circuit levels; the first input end of each parallel constant current source is connected with an input voltage, the second input end of each parallel constant current source is connected with the output end of the operational amplifier, the output end of each parallel constant current source is connected with the negative input end of the operational amplifier after being connected with a current transformer in series, the input end of the digital-to-analog conversion circuit is connected with an input digital control signal, and the output end of the digital-to-analog conversion circuit is electrically connected with the positive input end of the operational amplifier.
The power input is a common voltage-stabilized power supply (power frequency voltage-stabilized direct-current power supply or switching power supply), and the output is a high-precision low-ripple constant-current power supply expected by a user.
In the preferable scheme, the digital control signal is given in advance through a digital code, and is converted into a high-precision analog quantity through a DA (digital-to-analog) converter, the analog quantity is compared with a high-precision current transformer and is subjected to PI (proportional integral) to obtain a loop error signal, the constant current sources of n sub-modules at the lower end are driven, and the input control signals of the sub-modules are identical. The constant current sources are connected in parallel. The input end of the constant current source is connected with a voltage stabilizing input Vi, and the output end of the constant current source outputs current and is connected to the negative input end of the high-precision operational amplifier through a current transformer for PI control. The output end of the high-precision operational amplifier adopts a differential circuit to sample the output current of the high side, namely, the sampling is carried out through a sampling resistor. In order to reduce the loss of the sampling resistor, the voltage division ratio of the differential circuit can be improved.
The circuit structure compares the output current signal with the loop driving signal, performs proportion adjustment, and improves adjustment precision.
In a preferable scheme, the constant current source comprises a driving operational amplifier U1A, an MOS (metal oxide semiconductor) tube and an amplifying current-sharing operational amplifier U1B, wherein a D level of the MOS tube is connected with an input voltage, an S level of the MOS tube is connected with a sampling resistor in series to serve as an output end, and a G level of the MOS tube is electrically connected with the output end of the driving operational amplifier U1A; the two ends of the sampling resistor are respectively connected with the positive input end and the negative input end of the amplification current-sharing operational amplifier U1B, the output end of the amplification current-sharing operational amplifier U1B is connected with the negative input end of the driving operational amplifier U1A, and the positive input end of the driving operational amplifier U1A is connected with an input digital control signal. And the high-side current of the MOS tube is sampled, so that the integration and parallel connection of a plurality of MOS tubes are realized. The MOS parallel connection of the single module is used and the sub-modules of the multiple modules are connected in parallel.
Preferably, the resistance value is reduced by connecting a plurality of resistors in parallel to form a sampling resistor for sampling. The low sampling resistor realizes large current output and low power consumption.
Has the advantages that:
the good current equalizing effect meets the requirement of parallel connection of a plurality of modules; the method is not influenced by the requirement of customers on output grounding, and is suitable for floating ground design. The system design can meet the requirements of high precision of 0.01 percent of error and low ripple of less than 200 ppm. The MOS parallel connection of the single module is used and the sub-modules of the multiple modules are connected in parallel. The differential amplifying circuit is applied to the current sampling circuit. The low sampling resistor realizes large current output and low power consumption. Better loop design avoids system oscillation.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (4)
1. The utility model provides a high limit constant current source design circuit that flow equalizes of low pressure drop high accuracy low ripple which characterized in that, the design circuit that flow equalizes includes: the current transformers comprise a plurality of constant current sources, operational amplifiers and digital-to-analog conversion circuit levels;
the first input end of each parallel constant current source is connected with an input voltage, the second input end of each parallel constant current source is connected with the output end of the operational amplifier, the output end of each parallel constant current source is connected with the negative input end of the operational amplifier after being connected with a current transformer in series, the input end of the digital-to-analog conversion circuit is connected with an input digital control signal, and the output end of the digital-to-analog conversion circuit is electrically connected with the positive input end of the operational amplifier.
2. The low-voltage drop high-precision low-ripple high-side constant current source current-sharing design circuit of claim 1, further comprising a voltage-stabilizing power supply, wherein an input end of the voltage-stabilizing power supply is connected with an input voltage, and an output end of the voltage-stabilizing power supply is connected with an input end of each of the constant current sources which are connected in parallel.
3. The low-voltage-drop high-precision low-ripple high-side constant current source current-sharing design circuit of claim 1, wherein the constant current source comprises a drive operational amplifier U1A, a MOS (metal oxide semiconductor) transistor and an amplification current-sharing operational amplifier U1B, the stage D of the MOS transistor is connected with an input voltage, the stage S is connected with a sampling resistor in series and then serves as an output end, and the stage G is electrically connected with the output end of the drive operational amplifier U1A;
the two ends of the sampling resistor are respectively connected with the positive input end and the negative input end of the amplification current-sharing operational amplifier U1B, the output end of the amplification current-sharing operational amplifier U1B is connected with the negative input end of the driving operational amplifier U1A, and the positive input end of the driving operational amplifier U1A is connected with an input digital control signal.
4. The low-dropout high-precision low-ripple high-side constant current source current sharing design circuit according to claim 3, wherein the sampling resistor comprises two resistors connected in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220876474.2U CN217181449U (en) | 2022-04-16 | 2022-04-16 | High-side constant current source current-sharing design circuit with low voltage drop, high precision and low ripple |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220876474.2U CN217181449U (en) | 2022-04-16 | 2022-04-16 | High-side constant current source current-sharing design circuit with low voltage drop, high precision and low ripple |
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| Publication Number | Publication Date |
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| CN217181449U true CN217181449U (en) | 2022-08-12 |
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| CN202220876474.2U Active CN217181449U (en) | 2022-04-16 | 2022-04-16 | High-side constant current source current-sharing design circuit with low voltage drop, high precision and low ripple |
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| CN (1) | CN217181449U (en) |
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- 2022-04-16 CN CN202220876474.2U patent/CN217181449U/en active Active
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