SN71052 Constant voltage and constant current controller for battery chargers and adapters Semiconductor Description http:// www.auk.co.kr 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 SN71052 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 SOT-26 (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. ORDERING INFORMATION Application ◈ Battery chargers Product Marking Package SN71052 702 SOT-26 ◈ AC to DC adapters Block Diagram ▲ Marking Detail Information 702(①)□(②) ① Device Code ② Week Code KSD-I5P012-000 Dec, 2011 REV. 00 1 SN71052 ◈ Pin connection 1 : Vctrl 2 : GND 3 : OUT 4 : Ictrl 5 : Vsense 6: Vcc 6 5 4 1 2 3 ◈ Product Line-up 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 6 Vcc 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. Supply Voltage of the device. A small bypass capacitor (0.1 μF typ.) to GND, located as close to IC’s pins as possible, might be useful to get a clean supply voltage. KSD-I5P012-000 Dec, 2011 REV. 00 2 SN71052 ◈ Absolute Maximum Ratings ( Ta = 25℃ ) Parameter Symbol Limits Unit DC Supply Voltage VCC -0.3 to 23 V Power Dissipation Pd 500 mW Maximum Junction Temperature TJmax 150 ℃ Operating Junction Temperature Range Topr -10 ~ +85 ℃ Thermal Resistance Rthja 250 ℃/ W Storage Temperature Range Tstg -55 ~ +150 ℃ Parameter Symbol Limits Unit DC Supply Voltage VCC 2.5 to 20 V ◈ Operating Condition ( Ta = 25℃ ) KSD-I5P012-000 Dec, 2011 REV. 00 3 SN71052 ◈ Electrical characteristics ( VCC=+5V, TA=25℃ ; unless otherwise specified ) Characteristic Symbol Test Condition Min. Typ. Max. Ta = 25℃ - 0.8 2 0 < Ta < 85℃ - 1.5 - Ta = 25℃ 1 3.0 - 0 < Ta < 85℃ - 2.5 - Ta = 25℃ 1.198 1.210 1.222 0 < Ta < 85℃ 1.186 1.210 1.234 Ta = 25℃ - 40 - 0 < Ta < 85℃ - 100 - 1.5 7.0 - - - - Iout = 2.5 ㎃, Ta = 25℃ 97 100 103 0 < Ta < 85℃ 96 - 104 Ta = 25℃ - 25 - 0 < Ta < 85℃ - 30 - Unit [Total Current Consumption] Quiescent Current ICC ㎃ [ Voltage Control Loop OP-AMP ] Transconductance Gain Sink Current Only (1) Gmv Voltage Control Loop Reference (2) Vref Inverting Input Bias Current libv ㎃/㎷ V ㎁ [Current Control Loop] Transconductance Gain sink Current Only (3) Current Loop Reference (4) Current out of pin ICTRL at -100mV Gmi Vsense Iibi Ta = 25℃ 0 < Ta < 85℃ ㎃/㎷ ㎷ ㎂ [Output Stage] Low output Voltage at 10mA Sink current Vol - - 200 - ㎷ Output Short Circuit Current. Output to VCC. Sink Current Only Ios - - 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 (band-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 -100mV, 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. KSD-I5P012-000 Dec, 2011 REV. 00 4 SN71052 ◈ SOT-26 Outline Dimension (Unit : mm) ※ Recommend PCB solder land KSD-I5P012-000 Dec, 2011 REV. 00 [Unit: mm] 5 SN71052 The AUK Corp. products are intended for the use as components in general electronic equipment (Office and communication equipment, 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 safety device, etc.). AUK Corp. cannot accept liability to any damage which may occur in case these AUK Corp. products were used in the mentioned equipments without prior consultation with AUK Corp.. Specifications mentioned in this publication are subject to change without notice. KSD-I5P012-000 Dec, 2011 REV. 00 6