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ADI:Dual Port Bipolar Power Supply Circuit And Function Description

Auth:亿配芯城 Date:2019/11/16 Source:www.yibeiic.com Visit:94 Related Key Words: Inverter Controller power supply
Introduction

Dual quadrant supply provides positive or negative voltage to the same output port,The power can be usedLT 8714Quadrant controller is easy to manufacture。The two-quadrant power supply shown here can be used in a variety of applications,Window film(Changing the polarity will change the arrangement of crystal molecules)To test and measurement equipment。


Lt8714The data sheet describes how the dual quadrant power supply is in the first quadrant(Positive input、Positive output)And third quadrant(Positive input、Negative output)jobs。Please note,In two quadrants,Power supply source current,Thereby generating electrical energy instead of receiving electrical energy。The second quadrant and the fourth phenomenon generate receiving power。

Circuit description and function

Figure1Two-quadrant power supplyLT8714Circuit diagram。Power system byNMOS QN1、NMOS QN2、PMOS QP1、PMOS QP2、InductorL1、InductorL2、Coupling capacitorCCAnd input and output filter components。inductanceL1withL2Are two discrete decoupling inductors,Can reduce the cost of the converter。

In order to properly select active and passive components,It is necessary to understand the voltage stress and current levels in each quadrant。to this end,Please see the picture2The topology of the positive output function shown。
Figure1。based onLT8714Two-quadrant power supply circuit diagram,VINfor12 V,VOfor5 V,Voltage is6 A

Figure2 .Dual quadrant operational topology with positive output。

When the volt-second balance is in a steady state,The duty cycle can be derived from the following formula:

In order to verify the design,We modified the demo circuitDC2240A,And figure1The schematic shown is consistent。In both cases,When the nominal input voltage is12 V,The maximum current is6 ATime,The output voltage is5 v

The measurement efficiency of this design is shown in the figure3Shown。Positive output exceeds negative output,Consistent with theoretical calculations。In a negative output configuration,Higher voltage stress and current on the component。This configuration increases losses and reduces efficiency。
Figure3 .Converter efficiency curve:VINfor12Volt,VOUTfor+5Volt–5Volt,The maximum input and output is6Ann

Figure4Output voltage and control voltage are shownVCTRLGood linear relationship between。For this configuration,Circuit load1ωresistance,Control voltage range is0.1 Vto1 V
Figure4 .The output voltageVOUTAnd control voltageVCTRLDiagram。whenVCTRLFrom0.1 VIncrease to1 VTime,VOUTFrom–5vGradually change to+5 V

Use twoLTspicemodel,We can analyzeLT8714Performance。The first model shows that the power supply is in good condition,The second model uses uncoupled inductors。

in conclusion

This article describes a simple useLTC8714Two-quadrant voltage supply circuit。The design has been tested and verified,proveLTC8714Controller has good linearity。

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