BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 1 - 8/28/2006 total 8 pages the ballast control ic BL8305A is an improved vers ion of the bl8301. the BL8305A provides more functionality and is easier to use th an previous ic bl8301. the BL8305A optimizes the compatibility of driving mosfet half- bridge (mhf mhfmhf mhf) or bipolar half-bridge (bhf bhfbhf bhf). especially for bipolar half-bridge, the bl830 5a can automatically adjust the base current intensity (bc i auto bci auto bci auto bci auto- -- -adj adjadj adj), and guarantee that the half-bridge is in the optimum co ndition and reduces the power loss of half-bridge. it also improves the load adaptive of bipolar half-bridge. the BL8305A changes the timing component connection structure according to bl8301, so it is easier to design simply dimming products. the BL8305A has fully prot ections and all pins have latch immunity and esd protection, availa ble in both pdip14 and sop14 packages. features features features features driving both mhf and bhf automatically adjusting the bci of bhf programmable preheat frequency, preheat time and ru n frequency comprehensive protection micro power startup less than 150ua latch immunity and esd protection b bb brief introduction rief introduction rief introduction rief introduction 1. the BL8305A automatically provides a dead time 3 us for bhf and 1.2us for mhf. 2. the BL8305A features include on power preheat an d ignition. preheat frequency, preheat time and run mode frequency are all programmable by external components. 3. comprehensive protections such as protection fro m over current of half-bridge, filament failures, ignition failure, e nd of life, detecting base current of half-bridge and so on. 4. the BL8305A have an internal power regulator at 6.35v and micro power startup less than 150ua. 5. the BL8305A is a low cost design for ballast wit h few external components.
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 2 - 8/28/2006 total 8 pages 6. the BL8305A is available in both pdip14 and sop1 4 packages. all pins have latch immunity and esd protection. application information application information application information application information attention: this shematic for t8 36w only, other typ es lamp should change some components vcc vdc BL8305A gnd pro poff cpre ct ld fd hv out2 out1 rt rpre 1m 4.7u in4148 1n 15v 17.2k 100k 470p 0.1u 400v 175k 430k 10 10 13005 22n 13005 22n fr107 fr107 2mh 100n 8.2n t8 36w in4148 100k 0.1u 620k rstart rp1 rp2 ct rt cp c1 ro co 47n 30 22 22 2 rhv 0.1u fig. 1 attention: this shematic for t8 36w only, other typ es lamp should change some components vcc vdc BL8305A gnd pro poff cpre ct ld fd hv out2 out1 rt rpre 1m 4.7u in4148 1n 15v 17.2k 100k 470p 0.1u 400v 175k irf830 irf830 2mh 100n 8.2n t8 36w rstart rp1 rp2 ct rt cp c1 co 1u 0.1u 620k 2 0.1u 100 100 fig. 2
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 3 - 8/28/2006 total 8 pages block diagram block diagram block diagram block diagram lead assignments & definition lead assignments & definition lead assignments & definition lead assignments & definition pin# symbol description 1 vcc power supply 2 vdc 6.3v regulator output 3 rpre preheat frequency timing voltage 4 rt oscillator timing resistor 5 ct oscillator timing capacitor 6 cpre preheat timing capacitor 7 poff end of preheat output 8 gnd ic power &signal ground 9 pro current sensing input 10 fd filament detection input 11 ld window discriminator input 12 hv half-bridge output sense 13 out2 output2 14 out1 output1
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 4 - 8/28/2006 total 8 pages function description function description function description function description start start start start- -- -up and power supply up and power supply up and power supply up and power supply when the vcc is below the turn-on threshold of the ic, the BL8305A is in the low power consumption mode, oscillator and half-bri dge are shut off. the start-up capacitor (c1) is charged by 400v dc-bus through resistor (rstart). the charge current (icharge) is the current through rstart minus the start-up current (iqstart) drawn by the ic. so the choice basis of starting resistance rstart is: in most abominable cases, the current guaranteeing to pass rstart is iqstart of twice at least. once the capacitor voltage on vcc reaches the start -up threshold, the ic turns on and the output turns on. the rectified current c harges the capacitor at about 15v. the recommended capacitor value is 22uf. preheat mode, ignition mode and run mode preheat mode, ignition mode and run mode preheat mode, ignition mode and run mode preheat mode, ignition mode and run mode the preheat frequency, preheat time and run mode fr equency of BL8305A are all programmable by external components. the typical fr equency vs. time curve is as the picture shows. the preheat time is set by the external capacitor c p. an internal current source icprecharge charges cp when the ic started. the frequency remains at eh preheat frequency until the voltage on cp over the threshold voltage. after preheat the BL8305A begins to igniting the lamp. the total preheat time is:
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 5 - 8/28/2006 total 8 pages 2 1 2 7 * 249 .0 10 203 .0 p p p p preheat r r r c t + - = sec?preheat frequency is set by the voltage(vrpre) at pin3, the preheat frequency is: run rpre pre f v f = 6 . 1 35.6 2 1 2 pr + = pre pre pre e r r r r v . the run mode oscillating frequency is determined by the timing resistor rt and timing capacitor ct, t t run c r f = 374 .0 ? drive bhf or mhf drive bhf or mhf drive bhf or mhf drive bhf or mhf when driving bhf, a transformer with two secondary magnifies the output current of BL8305A and the half-bridge is drive by the magn ified current. the output voltage of half-bridge is divided by the resistor rhv and a n internal resistor about 40kohm in the pin hv and the BL8305A senses this waveform, and automatically adjusts the bci. the bci auto-adj is enabled at about 1 sec aft er the ignition. as showing in the figure, if bci is appropriate, the output of bl 8305a will be remain as the black line; if bci is low, the output of BL8305A will be increase as the dashed line; if bci is over driving, the output of BL8305A will be decrease as the dashdotted line.
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 6 - 8/28/2006 total 8 pages driving mhf the output connection is shows as the f igure above. the driving voltage is coupled from out1 by a 1:2 transformer i n order to separate the ic form high voltage. in mhf driving configuration, hv is connect to gnd directly, hence whether the BL8305A in preheat, ignition or r un mode the output of BL8305A is fixed. fault protection fault protection fault protection fault protection the BL8305A provides 3 leads to sensing fault: pro (pin9), fd (pin10) and ld (pin11). the pro pin is enabled at the ic turns on. once the voltage at this pin exceeds vpro (0.55v), the ic enters fault mode and both out puts are latched in the low state. the fd pin is used for filament detection; the ic w ill be restart when fd received a pulse. ld is a window discriminator. the high threshold is 4.3v, and the low threshold is 2.0v. ld has a pu ll up resistor 200k to vdc, and a pull down resistor 2 00k to gnd, in order to get a bias voltage 3.2v for the ld pin. at the end of ignition mode, ld will become effective after 1s delay(1s delay is used for avoid ignitions burr). once the BL8305A enters the fault mode, the ic will lock the state until vcc recycles back below the sh ut down threshold or the filament detection pin, sd, r eceives a pulse.
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 7 - 8/28/2006 total 8 pages filament filament filament filament preheat voltage remove preheat voltage remove preheat voltage remove preheat voltage remove the BL8305A provides a control signal (pin poff) to switch off the filament preheat voltage. when it done with the ignition and turns into run mode, poff will output a high level after about 1s delay (drive abi lity 20ma). this high level can close the switch k and turn off the filament voltag e. absol absol absol absolute maximum rations ute maximum rations ute maximum rations ute maximum rations absolute maximum ratings indicate sustained limits beyond which damage to the device may occur. all voltages parameter are absolu te voltages referenced to gnd, all current are defined positive into any lead . parameter symbol definition min. max units vcc(1) supply voltage --- 30 v v rpre preheat frequency timing voltage 1 7 v i rt oscillator output current --- 1 ma v pro current sensing voltage -0.3 vdc v iout1 output current of out1 200 ma iout2 output current of out2 200 ma t s storage temperature -55 150 ? note 1: only for bhf mode. in mhf mode vcc should l ess than 15v. recommended operating conditions recommended operating conditions recommended operating conditions recommended operating conditions parameter symbol definition min. typ. max. units vcc supply voltage -- 15 -- v v rpre preheat frequency timing voltage 1 -- 4 v i rt oscillator output current 20 82 200 ua v pro current sensing voltage 0 -- vdc v electrical characteristics electrical characteristics electrical characteristics electrical characteristics ta=25? vcc=15vrpre1=150krpre2=100krt=17.7kct=470pfcp= 0.1ufvpro=0v ld1 = 3.2vv hv =0 parameters symbol definition min. typ. max. units test condition power supply characteristics power supply characteristics power supply characteristics power supply characteristics vccon power on voltage - 13.7 - v vcc rising from 0v vccoff shut down voltage - 10 - v vcc falling from 15v vdc internal power regulator output - 6.35 - v vcc=15v
BL8305A BL8305A BL8305A BL8305A ballast control ic ballast control ic ballast control ic ballast control ic http://www.belling.com.cn - 8 - 8/28/2006 total 8 pages voltage i vdc internal power regulator output current 10 ma vcc=15v i qstart low power startup current --- --- 150 ua vcc 0.55v or ld < 2.0v or ld > 4.3v i qvcc quiescent current --- 3 --- ma out1?out2 without load oscillator oscillator oscillator oscillator characteristics characteristics characteristics characteristics 1 --- 300 khz fosc oscillator frequency --- 45 --- khz v ct oscillator capacitor voltage 2 4 v fosc = 45 khz preheat characteristics preheat characteristics preheat characteristics preheat characteristics i cprecharge cpre charge current --- 0.45 --- ua i cpredis cpre discharge current --- 0.97 --- ua fpre preheat frequency 71 khz tpre preheat time 1.4 s tign ignition time 140 ms v cprefault cpre voltage under fault protection --- 0 --- v driver output characteristics driver output characteristics driver output characteristics driver output characteristics (hv=gnd) (hv=gnd) (hv=gnd) (hv=gnd) vout1p-p p-p output voltage of out1 13 --- 15 v iout > 100ma iout1 p-p output current of out1 - --- 200 ma vout1p-p > 13v vout2p-p p-p output voltage of out1 13 --- 15 v iout > 100ma iout2 p-p output current of out1 - --- 200 ma vout1p-p > 13v tdeadmos dead time for mhf mode 1.2 us tdeadbip dead time for mhf mode 3.0 us hv6.3v protection characteristics protection characteristics protection characteristics protection characteristics v pro over current sensing threshold - 0.55 - v v ldup high threshold of ld - 4.3 - v v lddn low threshold of ld - 2.0 - v
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