ksd-i5p012-000 1 dec, 2011 rev. 00 SN71052 constant voltage and constant current controller for battery chargers and adapters marking detail information device code week code product marking package SN71052 702 sot-26 description the SN71052 is a highly integrated solution for smps applications requiring a dual control loop to perform cv (constant voltage) and cc (constant current) regulation. the sn71 052 integrates a voltage reference, two op-amps (with or-ed open-drain outputs), and a low-side current sensing circuit. the voltage reference, along with one op-amp, is the core of the voltage control loop; the current sensing circuit and the other op-amp make up the current control loop. the external components needed to complete the two control loops are: a resistor divider that senses the output of the power supply (adapter, battery charger) and fixes the voltage regulation set point at the specified value; a sense resistor that feeds the current sensing circuit with a voltage proportional to the dc output current; this resistor determines the current regulation set point and must be adequately rated in terms of power dissipation; frequency compensation components (r-c networks) for both loops. application ? battery chargers ? ac to dc adapters s s e e m m i i c c o o n n d d u u c c t t o o r r http:// www.auk.co.kr ordering information sot-26 702( ) ( ) block diagram
ksd-i5p012-000 2 dec, 2011 rev. 00 no. name function 1 vctrl inverting input of the voltage loop op-amp. the pin will be tied to the mid-point of a resistor divider that senses the output voltage. 2 gnd ground. return of the bias current of the device. 0 v reference for all voltages. the pin should be tied as close to the ground output terminal of the converter as possible to minimize load current effect on the voltage regulation set point. 3 out common open-drain output of the two internal op-amps. the pin, able to sink current only, will be connected to the branch of the optocoupler?s photodiode to transmit the error signal to the primary side. 4 ictrl non-inverting input of the current loop op -amp. it will be tied directly to the hot (negative) end of the current sense resistor 5 vsense inverting input of the current loop op-amp. the pin will be tied to the cold end of the current sense resistor through a decoupling resistor. 6 vcc supply voltage of the device. a small bypass capacitor (0.1 f typ.) to gnd, located as close to ic?s pins as possibl e, might be useful to get a clean supply voltage. ? pin connection ? product line-up SN71052 1 2 3 4 5 6 1 : vctrl 2 : gnd 3 : out 4 : ictrl 5 : vsense 6: vcc
ksd-i5p012-000 3 dec, 2011 rev. 00 parameter symbol limits unit dc supply voltage v cc -0.3 to 23 v power dissipation p d 500 mw maximum junction temperature t jmax 150 operating junction temperature range t opr -10 ~ +85 thermal resistance rthja 250 / w storage temperature range t stg -55 ~ +150 parameter symbol limits unit dc supply voltage v cc 2.5 to 20 v ? absolute maximum ratin g s ( ta = 25 ) SN71052 ? o p eratin g condition ( ta = 25 )
ksd-i5p012-000 4 dec, 2011 rev. 00 ( v cc =+5v, t a =25 ; unless otherwise specified ) characteristic symbol test condition min. typ. max. unit [total current consumption] quiescent current i cc ta = 25 - 0.8 2 ? 0 < ta < 85 - 1.5 - [ voltage control loop op-amp ] transconductance gain sink current only (1) g mv ta = 25 1 3.0 - ? / ? 0 < ta < 85 - 2.5 - voltage control loop reference (2) v ref ta = 25 1.198 1.210 1.222 v 0 < ta < 85 1.186 1.210 1.234 inverting input bias current l ibv ta = 25 - 40 - ? 0 < ta < 85 - 100 - [current control loop] transconductance gain sink current only (3) g mi ta = 25 1.5 7.0 - ? / ? 0 < ta < 85 - - - current loop reference (4) v sense iout = 2.5 ? , ta = 25 97 100 103 ? 0 < ta < 85 96 - 104 current out of pin ictrl at -100mv i ibi ta = 25 - 25 - ? 0 < ta < 85 - 30 - [output stage] low output voltage at 10ma sink current v ol - - 200 - ? output short circuit current. output to v cc . sink current only i os - - 35 70 ? 1) if the voltage on vctrl (the negative input of the amplifier) is higher than the positive amplifier input (vref = 1.210v), and it is increased by 1mv, the sinking current at the output out will be increased by 3.5ma. 2) the internal voltage reference is set at 1.210v (ban d-gap reference). the voltage control loop precision takes into account the cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the trans-conductance operational amplifier. the internal voltage reference is fixed by band-gap, and trimmed to 0.5% accuracy at room temperature. 3) when the positive input at ictrl is lower than -100 mv, and the voltage is decreased by 1mv, the sinking current at the output out will be increased by 7ma. 4) the internal current sense threshold is set to -100mv. the current control loop precision takes into account the cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the trans-conduction operational amplifier. ? electrical characteristics SN71052
ksd-i5p012-000 5 dec, 2011 rev. 00 SN71052 ? sot-26 outline dimension (unit : mm) recommend pcb solder land [unit: mm]
ksd-i5p012-000 6 dec, 2011 rev. 00 the auk corp. products are intended for the use as components in general electronic equipment (office and communication e quipment, measuring equipment, home appliance, etc.). please make sure that you consult with us before you use these auk corp. products in equipments which require high quality and / or reliability, and in equipments which could have major impact to the welfare of human life(atomic energy control, airplane, spaceship, transportation, combustion control, all types of safet y device, etc.). auk corp. cannot accept liability to any damage which may occur in case these auk corp. products were used in the mentioned equi pments without prior consultation with auk corp.. specifications mentioned in this publicati on are subject to change without notice. SN71052
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