unisonic technologies co., ltd upsrb01b preliminary linear integrated circuit www.unisonic.com.tw 1 of 7 copyright ? 2015 unisonic technologies co., ltd qw-r103-096.a high precision cc/cv primary side switching regulator ? description the utc upsrb01b is a primary control unit for switch mode charger and adapter applications . the controlled variable is transferred by an auxiliary winding from the secondary to the primary side. the device uses pulse frequency modulation (pfm) method to build discontinuous conduction mode (dcm) flyback power supplies. the utc upsrb01b operates in primary-side sensing and regulation. opto-coupler and t l431 could be eliminated. it also eliminates the need of loop compensation circuitry while maintaining stability. the utc upsrb01b achieves high precision cv/cc regulation and high power efficiency. it offers comprehensive protection coverage with auto-recovery features including cycle-by-cycle current limiting, output over voltage protection, v dd over voltage protection, feed back loop open protection, short circuit protection, leading edge blanking, otp, v dd under voltage lockout, etc. ? features sot-26 4 5 3 2 1 6 * 5% constant voltage regulation at universal ac input * primary side control without tl431 and opto-coupler * high precision constant current regulation at universal ac input * programmable cv and cc regulation * eliminates control loop compensation circuitry * flyback topology in dcm operation * random frequency modulation to reduce system emi * driver bjt switch * built-in leading edge blanking * built-in primary winding inductance compensation * open circuit protection * output over voltage protection * v dd over voltage protection * short circuit protection * over temperature protection ? ordering information ordering number package packing UPSRB01BG-AG6-R sot-26 tape reel UPSRB01BG-AG6-R (1)packing type (2)package type (3)green package (1) r: tape reel (2) ag6: sot-26 (3) g: halogen free and lead freee
upsrb01b preliminary linear integrated circuit unisonic technologies co., ltd 2 of 7 www.unisonic.com.tw qw-r103-096.a ? marking ? pin configuration ? pin description pin no. pin name description 1 gnd ground 2 cs current sense input. 3 base base drive for power bjt. 4 fb the voltage feedback from the auxiliary winding 5 vc low pass filter capacitor for cable compensation 6 v dd power supply ? block diagram
upsrb01b preliminary linear integrated circuit unisonic technologies co., ltd 3 of 7 www.unisonic.com.tw qw-r103-096.a ? absolute maximum rating parameter symbol ratings unit v dd voltage v dd -0.3~30 v vc voltage v c -0.3~7 v base voltage v base -0.3~7 v cs input voltage v cs -0.3~7 v fb input voltage v fb -0.3~7 v junction temperature t j -40~150 c operating temperature t opr +150 c storage temperature t stg -55~150 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? electrical characteristics (t a =25c, v dd =15v, if not otherwise noted) parameter symbol test conditions min typ max unit supply voltage (v dd ) section start up current i st v dd =11v 1 3 a static current i op v dd =15v 300 400 a turn-off threshold voltage v th(off) 6.0 6.8 7.6 v turn-on threshold voltage v th (on) 11.5 12.5 13.5 v v dd over voltage protection v dd_ovp 25 27 29 v operating voltage 25 v current sense input section leb time t leb 0.5 s over current threshold v cs 485 500 515 mv ocp propagation delay t d_oc from ocp comparator to base drive 100 ns fb input section reference voltage for feedback threshold v fb 1.98 2.00 2.02 v minimum pause t pause_min 2.0 s maximum pause t pause_max 8 10 12 ms otp section over temperature protection t_otp 150 c base drive section base sourcing maximum current i out(source) 20 30 40 ma base sourcing current after pre-off i out(pre) 0.5 1 1.5 ma base drive low side on resistor r dson_l 1 ?
upsrb01b preliminary linear integrated circuit unisonic technologies co., ltd 4 of 7 www.unisonic.com.tw qw-r103-096.a ? operation description the utc upsrb01b is a primary control unit for switch mode charger and adapter applications. it operates in primary-side sensing and regulation. opto-coupler and tl43 1 could be eliminated. proprietary built-in cv and cc control can achieve high precision cv/cc performance. it uses pulse frequency modulation (pfm) method to build discontinuous conduction mode (dcm) flyback power supplies. startup control the v dd pin of utc upsrb01b is connected to the line input through a resistor. a large value startup resistor can be used to minimize the power loss in app lication because the start current of utc upsrb01b is very low. when the v dd voltage reaches v th (on) , the internal startup circuit is disabled and the ic turns on. operating current the operating current of utc upsrb01b is as low as 400 a. good efficiency and very low standby power can be achieved. constant voltage operation the output voltage is defined by the transmission ratio between the secondary and auxiliary winding. the utc upsrb01b captures the auxiliary winding feedback voltage at fb pin and operates in constant-voltage (cv) mode to regulate the output voltage. the auxiliary voltage reflects the output voltage is given by: v ? + v n n = v o s a aux (1) where v indicates the drop voltag e of the output diode. figure2. auxiliary voltage waveform via a resistor divider connected between the auxiliary winding and fb, the v aux is sampled at the tsampling end and it is hold until the next sampling. the sampled voltage is compared with 2v reference voltage and the error is amplified. the error amplifier output re flects the load condition and controls the toff time to regulate the output voltage, thus constant output voltage can be achieved. constant current operation when the sampled voltage is below 2v reference voltage a nd the error amplifier output reaches its maximum, thus utc upsrb01b operates in constant-current (cc) mode. the cc point and maximum output power can be externally adjusted by external current sense resistor r cs. the larger rcs, the sma ller cc point is, and the smaller output power becomes.
upsrb01b preliminary linear integrated circuit unisonic technologies co., ltd 5 of 7 www.unisonic.com.tw qw-r103-096.a ? operation description (cont.) figure3. adjustable output power by changing r cs figure4. secondary current waveform in cc operation, the cc loop control function of utc upsrb01b will keep a fixed proportion between secondary inductance de-magnetization time (tdemag) and switch ing cycle time (tsw). the fixed proportion is 2 1 = t t sw demag (2) thus the output current is given by: pk s p sw demag pk s p out i n n 4 1 = t t i n n 2 1 = i (3) current sensing and leading edge blanking cycle-by-cycle current limiting is offered in utc upsrb01b . the switch current is detected by a sense resistor into the cs pin. when the power switch is turned on, a turn-on spike will occur on this resistor. a 500ns leading-edge blanking is built in to avoid false-termination of the switching pulse so that the external rc filtering is no longer needed.
upsrb01b preliminary linear integrated circuit unisonic technologies co., ltd 6 of 7 www.unisonic.com.tw qw-r103-096.a ? operation description (cont.) drive bjt the driver is a push pull stage with the supply voltage v dd . it provides the driving current for the external power bipolar transistor. the output signal is current-limited to i out(source) . protection control good power supply system reliability is achieved with its comprehensive protection features including output over-voltage protection, v dd over voltage protection, otp, feedback loop open protection, cycle-by-cycle current limiting, short circuit protection, leading edge blanking and uvlo, etc. v dd is supplied by transformer auxiliary winding output. the output of utc upsrb01b is shutdown when v dd drops below v th(off) and the power converter enters power on start-up sequence thereafter.
upsrb01b preliminary linear integrated circuit unisonic technologies co., ltd 7 of 7 www.unisonic.com.tw qw-r103-096.a ? typical application circuit (5v/1a) bom reference component reference component bd1 bd 1a/600v r3 r 2.4k ? 1206 5% l1 choke r1,r2 r 4.7m ? 1206 5% c1 ec 4.7u f 400v 105c r4 r 330k ? 1206 5% c2 ec 4.7u f 400v 105c r6 r 20k ? 0805 1% c3 cc 1n f 1000v 1206 r7 r 3.3k ? 0805 1% c4 ec 2.2u f 50v 105c r9 r 1.1 ? 1206 5% c6 ec 680u f 10v 105c t1 ee-16 c8 cc 22n f 50v 0805 f1 fuse 1a 250vac d5, d7 utc 1n4007 q1 utc mje13003 d6 utc sb340 utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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