EST7502B pc power supply pwm with supervisor www.esthome.com 1 2007-10-15 v2 general description the EST7502B is a pulse?width modulation (pwm) contro l circuit with complete protection circuits for used in the smps (switched mode power supply). it contains various functions, which are over voltage protection, under voltage protection, powe r good output (pgo), remote on/off control and etc. it can minimize external components of swit ching power supply systems in personal computer. over voltage protection (ovp) monitors 3.3v, 5v , 12v and pt input voltage level. under voltage protection (uvp) monitors 3.3v, 5v and 12v input voltage level. power good output monitors the voltage level of power supply. features ? complete pwm control and protection circuitry ? over voltage protection for 3.3v / 5v / 12v / pt ? under voltage protection for 3.3v / 5v / 12v ? 280ms pg time delay ? power good output is open drain output ? pwm control output are open drain output ? 280 ms time delay for uvp ? remote on/off function de?bounce time ? soft-start function built-in ? 16?pin dual in?line package pin configuration ordering information order number package shipping top marking EST7502B dip 16 v33 v5 v12 pt gnd rt c1 c2 vadj opnegin opout vcc det pg ss rem 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8
EST7502B pc power supply pwm with supervisor www.esthome.com 2 2007-10-15 v2 pin description pin no. pin name type function 1 v33 i ovp/uvp input for 3.3v. 2 v5 i ovp/uvp input for 5v. 3 v12 i ovp/uvp input for 12v. 4 pt i extra ovp protection input. 5 gnd p ground. 6 rt o oscillation frequency set by external resistor. 7 c1 o pwm open drain output 1. 8 c2 o pwm open drain output 2. 9 rem i remote on/off input. rem=?low? that means the ma in smps is turned-on. rem=?high?, the main smps is turned-off. 10 ss o soft start function set by external capacitor. 11 pg o power good signal. pg= ?high? means ?power good?. pg= ?low? means ?power fail?. 12 det i extra protection input. 13 vcc p supply voltage. 14 opout o op compensation output. 15 opnegin i op compensation negative input. 16 vadj i op compensation positive input , feedback voltage sense input.
EST7502B pc power supply pwm with supervisor www.esthome.com 3 2007-10-15 v2 block diagram absolute maximum ratings, vcc=5.5v characteristics symbol value unit supply voltage vcc 5.5 v drain output voltage vcc1, vcc2 5.5 v drain output current icc1, icc2 200 ma power dissipation pd 200 mw operating temperature topr -20 ~ +85 storage temperature tstg -65 ~ +150 c dq qn r sq + - + - + - + - + - + - + - + - + - + - + - + - v33 v5 v12 pt qout pg rem remonf remon ss det c1 rt vadj opnegin c2 opout uvp 110us 0.62v 0.62v 510us 280ms delay 280ms delay vss clr in out [11] in out 5k soft_start controller [10] detcmp pwmcmp pwm control osc clr 2.45v error amp [16] [15] 4.5ms delay 36ms delay [14] [6] [12] [9] [4] [3] [2] [1] ovp ov ov ov ov uv uv uv [8] [7]
EST7502B pc power supply pwm with supervisor www.esthome.com 4 2007-10-15 v2 electricalcharacteristics, ta=25 , v cc =5v, characteristics symbol test condition min. typ. max. unit error amp section open loop voltage gain 0.5v ~ 3.5v 75 85 db cross over point 0db 1000 khz opneg bias voltage opneg open 2.40 2.45 2.50 v power supply rejection ratio p s rr 4 5 db output section output saturation voltage vdssat id=200ma 1.1 1.3 v drain off-state current idoff vcc=vd=vs=0v 2 10 ua rising time tr 100 200 ns falling time tf 50 200 ns protection section v33 3.8 4.1 4.3 v v5 5.8 6.2 6.6 v v12 4.4 4.6 4.9 v pt 1.23 1.28 1.33 v over voltage protection ovp tg.ov 510 us v33 1.7 1.9 2.2 v v5 2.7 3.0 3.3 v v12 2.1 2.4 2.7 v under voltage protection uvp tg.uv 120 us uvp disable voltage pt 0.55 0.62 0.68 v uvp delay time td.uvp 100 280 380 ms remote on/off section rem high input voltage vremh 1.8 v rem low input voltage vreml 0.7 v rem pull high voltage vremo 2.0 5.25 v rem delay time td on/off 40 ms power good section detect input voltage vdet 0.68 v pg output pull?up resistor rpup, pg 5 k pg output load resistor rpg 0.5 1 2 k pg delay time 180 280 380 ms sink current ipg.sink vpg=0.2v 10 ma soft start section sink current of ss iss.sink rt=100k ? 15 ua source current of ss iss.source 310 ua vcc under voltage lockout(uvlo) start-up voltage 4.2 v total device standby supply current icc rem=5v 10 20 ma oscillation section oscillation frequency fosc rt=100k 70 75 80 khz
EST7502B pc power supply pwm with supervisor www.esthome.com 5 2007-10-15 v2 application note 1. input impedance: pin no. pin name input impedance 1 v33 52k 2 v5 81k 3 v12 52k 4 pt 24 k +4.6 k 2. sawtooth osc. function: 3.remote on/off rem remonf remon ss trem trem toff toff
EST7502B pc power supply pwm with supervisor www.esthome.com 6 2007-10-15 v2 4. under voltage protection delay time 5. pulse width modulation block the output pulse width modulation is ge nerated by comparison of the saw?tooth waveform from the capacitor c t to the feedback of the voltage. therefore, an increase in fee dback control signal amplitude cause a linear decrease of the output pulse width. also, the ss(dtc and soft-start) limits the output pulse width. the timing diagram is shown as below: 6. the function of ?pt?: this signal is prepared for extra ovp/opp (v pt > 1.28v) or another disable under voltage protection function (v pt < 0.62v) rem remon u vp td,uvp ct ff-q ff-clk c2 c1 ff-qn dtc pwm out
EST7502B pc power supply pwm with supervisor www.esthome.com 7 2007-10-15 v2 7. reference application circuit: 8. in some application power system, adding an external resistor (r9) could reduce the peak value spike from the environments to pin 9 (rem) and avoid pin 9 (rem ) damaged by the external noise. external dimensions dim inches millimeters min max min max a 0.740 0.770 18.80 19.55 b 0.250 0.270 6.35 6.85 c 0.145 0.175 3.69 4.44 d 0.015 0.021 0.39 0.53 f 0.040 0.070 1.02 1.78 g 0.100bsc 2.54bsc h 0.050bsc 1.27bsc j 0.008 0.015 0.21 0.38 k 0.110 0.130 2.80 3.30 l 0.295 0.305 7.50 7.74 m 0 10 0 10 s 0.020 0.040 0.51 1.01 dip-16 outline dimensions
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