Qhia luv luv ntawm DC Numerically Controlled Adjustable Regulated Power Supply
DC stabilized fais fab mov yog ib qho khoom siv hluav taws xob uas nquag siv, uas tuaj yeem ua kom ruaj khov qhov hluav taws xob thaum cov kab hluav taws xob hloov pauv lossis hloov pauv. Ib qho hluav taws xob qis, high-precision voltage regulator muaj qhov tseem ceeb ntawm kev siv tus nqi hauv kev ntsuas, kev tswj hwm kev lag luam thiab kev ntsuas. Cov zis voltage ntau ntawm cov tswj fais fab mov muab rau hauv qhov tsim no yog 0-18 V, qhov ntsuas kev khiav hauj lwm tam sim no yog 0.5 A, thiab nws muaj ntxiv rau , - kauj ruam voltage hloov kho, qhov tsawg kawg yog kauj ruam yog 0.05 V, thiab cov ripple tsis ntau tshaj 10 mV, Tsis tas li ntawd, LCD kua siv lead ua zaub tuaj yeem siv los tso saib nws cov nqi hluav taws xob tso tawm.
Taw qhia
1 System hardware design
Lub kaw lus yog tsim los ntawm cov khoom siv hluav taws xob, kev tswj hluav taws xob, kev hloov pauv D / A, cov zaub thiab cov keyboard module, thiab daim duab 1 qhia txog daim duab thaiv ntawm cov qauv thiab cov hauv paus ntsiab lus ntawm DC NC fais fab mov.
1.1 System zog module
Lub dual 17.5V AC voltage tau txais tom qab 220V mains yog nqis los ntawm 220V / 17.5V transformer tuaj yeem kho tau los ntawm tus choj tag nrho kom tau txais ob qhov hluav taws xob ntawm ± 21V, ib qho ntxiv rau 21V voltage yog nkag mus rau lub regulator raj li ib fais fab mov rau cov zis tawm sab nraud, thiab lwm yam Txhua txoj kev los ntawm peb lub davhlau ya nyob twg voltage regulator 7815 kom tau ntxiv 15V, thiab tom qab ntawd dhau ntawm 7805 kom tau ntxiv 5V voltage. Lub -21V voltage tau txais -15V voltage los ntawm peb-terminal voltage regulator MC7915, uas yog siv los ua lub zog ua hauj lwm ntawm lub system nws tus kheej.
1.2 Voltage hloov module
The voltage adjustment module circuit in the regulated power supply is shown in Fig. 2 . Among them, the adjustment tube adopts the form of composite tube (composed of Q1 and Q3) to achieve high current output. Since this design requires Iomax=0.5A, Iomin=0A, pm=(Vimax-Vomin)Iomax=(18-0)×0.5 =9W, therefore, the adjustment tube in this circuit can choose TIp41 (its Icmax=6A>Iomax=0.5A; pcw=65W>9W, VCEOmax=100V>18V), tau kawg, 2N5832 kuj siv tau.
Kev sib piv ntawm kev sib piv ntawm lub voj voog yog tsim los nrog kev ua haujlwm amplifier NE5534, uas muaj cov yam ntxwv ntawm cov hom kev tsis lees paub qhov sib piv, cov lus teb ceev ceev thiab siab slew npaum li cas. Thaum tsim, ib qho kev faib hluav taws xob sib faib hluav taws xob tuaj yeem tsim los ntawm R10, R11A, thiab R12, thiab R10 / (R11A ntxiv rau R12)=1/4 yuav tsum tau, uas yog, thaum cov zis
Thaum muaj qhov hluav taws xob △UO{{0}}}05V, △Ua=0.04V, uas yog raws li kev hloov pauv ntawm cov zis ntawm DAC (10/{{5 }}.04V=1LSB). Qhov tseeb, tom qab DAC hloov dua siab tshiab los hloov cov tam sim no mus rau hauv qhov hluav taws xob thiab ua kom lub zog loj, qhov tau txais 10V voltage tuaj yeem xa mus rau qhov tsis yog inverting davhlau ya nyob twg ntawm tus sib piv NE54534 raws li qhov siv voltage rau kev sib piv. Txij li thaum DAC0832 yog ib qho 8-ntsis D/A converter, nws muaj 255 kauj ruam. Yog li, thaum CpU tswj cov DAC sib txawv los ntawm 1LSB, qhov hloov pauv hauv Va yog 0.04V, yog li qhov hloov kho tau ntawm Uout yog 0.05V (qib loj). Qhov kev tawm tswv yim tsis zoo Circuit Court tsim los ntawm NE5534, Q1, Q3 thiab sampling Circuit Court tuaj yeem paub lub hom phiaj ntawm kev kho cov zis voltage (voltage stabilization).
The overcurrent protection in the circuit is completed by R9 and 02. When Io>{{0}}.7A, VR9=R9Io Ntau dua lossis sib npaug rau 1 × 0.7=0.7V, lub sijhawm no, Q2 tau qhib, thiab shunts lub hauv paus ntawm Kev hloov kho raj Q3, kom qhov kev tiv thaiv ntawm TIp41 nce thiab cov zis hluav taws xob txo qis, yog li ua tiav lub hom phiaj ntawm kev tiv thaiv kwj. Yog tias tsim nyog, lub teeb liab-emitting diode kuj tseem tuaj yeem txuas nrog ua qhov ntsuas tshaj tam sim no. Kev tiv thaiv luv luv ntawm lub kaw lus yog ua tiav los ntawm fuse.
1.3D / A hloov dua siab tshiab module
Lub digital-rau-analog hloov dua siab tshiab Circuit Court nyob rau hauv no system yog qhia nyob rau hauv daim duab 3. Nws muaj DAC0832, ob-theem low-drift ua hauj lwm amplifier μA714 thiab VREF circuit. DAC0832 thiab ua haujlwm amplifier U3A hloov cov 8-ntsis binary cov ntaub ntawv xa los ntawm CpU rau hauv qhov hluav taws xob ntawm 0-5V, thiab tom qab ntawd thim rov qab amplify ob zaug los ntawm kev ua haujlwm amplifier U3B kom tau txais qhov voltage ntawm 0-10V. Yog li ntawd, qhov kev daws teeb meem ntawm DAC yog 10/({14}})=0.04V, uas yog, qhov hloov ntawm cov ntaub ntawv tso tawm los ntawm CpU rau DAC yog 1Bit, thiab qhov hloov ntawm DAC tso zis voltage yog 0.04V. Lub VREF Circuit Court muab qhov kev siv hluav taws xob rau DAC, thiab kho R5A khaws qhov siv hluav taws xob ntawm 5V.
1.4 Zaub thiab keyboard module
Cov khoom siv hluav taws xob thiab cov keyboard Circuit Court nyob rau hauv cov khoom siv hluav taws xob no tau pom hauv daim duab 4. Tom qab cov zis hluav taws xob raug txwv los ntawm R13 thiab ua piv txwv los ntawm R14, nws tuaj yeem xa mus rau TLC 2453-1 rau kev hloov pauv hloov pauv mus rau digital. Lub TLC2453-1 hauv daim duab 4 yog ib qho 11-channel, 12- ntsis serial A/D converter nrog {{10}} ntsis daws teeb meem, lub sij hawm hloov dua siab tshiab ntawm 1{ {29}} μs, 11 analog input channels, 3 built-in self-test modes, thiab tus nqi piv txwv ntawm 66 kbps, Linearity yuam kev ± 1LSBmax, nrog kev hloov pauv cov txiaj ntsig EOC tib lub sijhawm, thiab tuaj yeem ua unipolar lossis bipolar tso zis . Programmable tso zis cov ntaub ntawv ntev ntawm nws cov programmable MSB lossis LSB preamble. Lub moos zaus ntawm TLC2453-1 yog 4.1MHz, qhov piv txwv teeb liab ntawm lub hwj chim tso zis voltage Uo yog input los ntawm IN {{30}}, lub I/O moos davhlau ya nyob twg, cov ntaub ntawv input davhlau ya nyob twg, hloov dua siab tshiab cov ntaub ntawv tso zis davhlau ya nyob twg thiab cov chaw xaiv nti ntawm lub nti txuas nrog p2.3, P2.2, p2.1, thiab p2.0 txuas nrog, thiab tom qab ntawd tso tawm los ntawm p0 chaw nres nkoj tom qab ua tiav los ntawm ib-chip microcomputer, thiab tom qab ntawd xa mus rau lub cim ua kua siv lead ua zaub SMC1602A los tso saib cov zis hluav taws xob tom qab tau tsav los ntawm kev cais tawm 9A472J. Nyob rau hauv lub voj voog, cov siv lead ua oscillator zaus ntawm AT89S51 microcontroller yog 12MHz, thiab p1.0 ~ p1.3 txuas nrog lub zog tswj khawm. Thaum nce qhov voltage, hu rau lub pob S1 coarsely nrog ib kauj ruam ntawm 1V, hu rau S2 finely nrog ib kauj ruam ntawm 0.05V; Thaum txo qhov voltage, hu rau S3 coarsely nrog ib kauj ruam ntawm 1V, thiab hu rau S4 finely nrog ib kauj ruam ntawm 0.05V. Nyob rau hauv txoj kev no, cov zis hluav taws xob tuaj yeem hloov kho rau qhov xav tau voltage los ntawm lawv cov organic ua ke.
