OB2305MP

OB2305 High Precision CC/CV Primary-Side Controller FEATURES OB2305 is a high performance offline PSR controller for low power AC/DC charger and adapter applications. It operates in primary-side sensing and regulation. Consequently, opto-coupler and TL431 could be eliminated. Proprietary Constant Voltage (CV) and Constant Current (CC) control is integrated as shown in the figure below. In CC control, the current and output power setting can be adjusted externally by the sense resistor Rs at CS pin. In CV control, multi-mode operations are utilized to achieve high performance and high efficiency. In addition, good load regulation is achieved by the built-in cable drop compensation. Device operates in PFM in CC mode at large load condition and it operates in PWM with frequency reduction at light/medium load. The chip consumes very low operation current. It achieves less than 30mW standby power to meet strict standby power standard. OB2305 offers comprehensive protection coverage with auto-recovery feature including Cycle-by-Cycle current limiting, VDD over voltage protection, feedback loop open protection, short circuit protection, built-in leading edge blanking, VDD under voltage lockout (UVLO), OTP etc. OB2305 is offered in SOT23-6 package (for up to 10W application) and SOP8 package (for up to 15W application).  Primary-side sensing and regulation without TL431 and opto-coupler  High precision constant voltage and current regulation at universal AC input  Multi-mode PWM/PFM operation for efficiency improving  Less than 30mW standby power consumption at 230V with typical application circuit  Programmable CV and CC regulation  Built-in dynamic signal detection from 2nd-side synchronous rectification  Built-in line voltage and primary winding inductance compensation  Programmable cable drop compensation  No need for control loop compensation  Precise internal over temperature protection  Audio noise free operation  Built-in leading edge blanking (LEB)  Ultra low start-up current and low operating current  Comprehensive protection coverage with auto-recovery  VDD over voltage protection  VDD under voltage lockout with hysteresis (UVLO)  Cycle-by-cycle current limiting  Feedback loop open protection  Output short circuit protection  Over temperature protection (OTP) on fid en tia lt o 福 佳 GENERAL DESCRIPTION APPLICATIONS br ig ht c Low Power AC/DC offline SMPS for  Cell Phone Charger  Digital Cameras Charger  Small Power Adapter  Auxiliary Power for PC, TV etc.  Linear Regulator/RCC Replacement Figure.1. Typical CC/CV Curve O n- TYPICAL APPLICATION ©On-Bright Electronics Confidential -1- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller GENERAL INFORMATION Ordering Information Part Number Description OB2305MP SOT23-6, Pb-free, T&R OB2305CP SOP8, Pb-free in Tube OB2305CPA SOP8, Pb-free in T&R Pin Configuration The pin map is shown as below: SOT23-6 佳 Package Dissipation Rating Package RθJA (℃/W) SOT23-6 200 SOP8 150 SOP8 1 8 NC 2 7 SD 3 6 CS 4 5 VDD GND ratings” may cause permanent damage to the device. These are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute maximum-rated conditions for extended periods may affect device reliability. GND FB O n- br ig ht c GATE on fid en tia lt o 福 Absolute Maximum Ratings Parameter Value VDD Voltage -0.3 to 30V FB Input Voltage -0.3 to 7V CS Input Voltage -0.3 to 7V SD Input Voltage -0.3 to 24V GATE Input Voltage -0.3 to 24V Min/Max Operating Junction -40 to 150 ℃ Temperature TJ Operating Ambient -40 to 150 ℃ Temperature TA Min/Max Storage -55 to 150 ℃ Temperature Tstg Lead Temperature 260 ℃ (Soldering, 10secs) Note: Stresses beyond those listed under “absolute maximum OB2305 High Precision CC/CV Primary-Side PWM Controller Recommended operating condition Symbol Parameter Range VDD VDD Supply Voltage 9 to24V X Package X Package Pb-free M:SOT23-6 C:SOP8 ©On-Bright Electronics Confidential -2- X P:Pb-free Packing Blank:Tube A: Tape/Reel Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller Marking Information YWWZZZ 305YWW . ZZZ s 佳 OB2305CP Y: Year Code Y:Year Code WW:Week Code(01-52) ZZZ: Lot code s: Internal code 福 s o WW: Week Code (01-52) on fid en tia lt ZZZ:Lot Code C: SOP8 P:Pb-free Package S: Internal Code(Optional) TERMINAL ASSIGNMENTS Pin Num Pin Name I/O Description 1 FB I 2 GND P 3 CS I 4 SD O Source driver of power MOSFET 5 GATE O Gate driver of power MOSFET. 6 VDD P Power Supply The voltage feedback from auxiliary winding. Connected to resistor divider from auxiliary winding reflecting output voltage. Ground O n- br ig ht c Power MOSFET source ©On-Bright Electronics Confidential -3- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller O n- br ig ht c on fid en tia lt o 福 佳 BLOCK DIAGRAM ©On-Bright Electronics Confidential -4- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller ELECTRICAL CHARACTERISTICS Min VDD=UVLO_OFF-1V Static current ht c 485 Unit 5 15 uA 0.65 1.0 mA 14.8 15.8 7.6 8.2 27 28 V V V 330 100 500 550 100 50 100 24 515 V ns ns mV mV mV us ns 2.475 2.50 2.525 V 2.0 200 1.55 us Hz V 22 24 26 uA 12 13.5 15 180 30 1.0 2 V ns ns Ω br ig nO Typ. Max 福 13.8 7.0 26 on fid en tia lt UVLO(OFF) VDD under voltage lockout exit UVLO(ON) VDD under voltage lockout enter VDD_OVP VDD over voltage protection Max. Operating Voltage Current Sense Input Section TLEB LEB time TD_OC OCP propagation delay Vth_ocp_min Minimum over current threshold Vth_ocp_max Maximum over current threshold Vcs_mini Minimum CS threshold Ton_max Maximum Ton Td_oc OCP propagation delay FB Input Section Reference voltage for feedback Vref_fb threshold Tpause_min Minimum Toff F_min Minimum frequency Vth_cc_shutdown CC mode shut down threshold Maximum cable compensation Icomp_cable current Gate Drive Section V_clamp Output clamp voltage level Tr Output rising time CL=0.22nF Tf Output falling time CL=0.22nF Rdson_l Internal switch on resistor Before startup, SD pin leakage Isw_leak Vsw=VDD-1V current Output Over Voltage Protection V_OVP Output Over voltage threshold On chip Over temperature Section o I static Test Conditions 佳 (TA = 25℃, VDD=15V, if not otherwise noted) Symbol Parameter Supply Voltage (VDD) Section I start-up Start up current 1 uA 2.9 3.0 3.1 V T_otp Over temperature trigger point 150 165 180 ℃ T_otp_rec Over temperature recovery point 115 130 145 ℃ ©On-Bright Electronics Confidential -5- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller CHARACTERIZATION PLOTS Ivdd_startup(uA) vs Temperature 1000 5 800 4.6 400 200 4.2 佳 600 3.8 3.4 0 0 4 8 12 16 20 3 24 28 -40 on fid en tia lt 140 Icable(uA) vs Tem perature Icable(uA)) Vref(V) 110 24 2.6 2.4 2.2 23 22 21 2 -40 -10 20 50 80 110 20 -40 140 -10 UVLO_ON(V) vs Temperature 50 80 110 140 UVLO_OFF(V) vs Temperature 15 br ig 8 20 Temperature( ℃) ht c Temperature( ℃) UVLO_OFF(V) 7.8 7.6 7.4 n- UVLO_ON(V) 80 25 2.8 7.2 O 50 Temperature(℃) Vref(V) vs Tem perature 3 20 o VDD(V) -10 福 Ivdd_startup (uA) Istatic(uA) VDD vs Istatic 7 14.8 14.6 14.4 14.2 14 -40 -10 20 50 80 110 140 -40 Temperature(℃) ©On-Bright Electronics -10 20 50 80 110 140 Temperature(℃) Confidential -6- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller OB2305 is a cost effective PSR controller optimized for off-line low power AC/DC applications including battery chargers. It operates in primary side sensing and regulation, thus opto-coupler and TL431 are not required. Proprietary built-in CV and CC control can achieve high precision CC/CV control meeting most charger application requirements. IS   Fast Start up Control Startup current of OB2305 is designed to be very low so that VDD could be charged up above UVLO threshold and starts up quickly. The startup resister is connected between the rectified high voltage DC rail and the gate of the power MOSFET. The power MOSFET current charges VDD capacitor through internal diode from SD pin to VDD pin. Thus, a large value startup resistor can therefore be used to minimize the power loss in application. 佳 flyback system (Refer to Typical Application Diagram in page1). In the DCM flyback converter, the output voltage can be sensed via the auxiliary winding. During MOSFET turn-on time, the load current is supplied from the output filter capacitor, Co, and the current in the primary winding ramps up. When MOSFET turns off, the energy stored in the primary winding is transferred to the secondary side and the current in the secondary winding is OPERATION DESCRIPTION NP  IP NS (1) N AUX  (VO  V ) NS (2) o V AUX  福 The auxiliary voltage reflects the output voltage as shown in Figure.2 and it is given by ht c on fid en tia lt Where V indicates the voltage drop of the output Diode. Figure.2. Auxiliary voltage waveform Via a resistor divider connected between the auxiliary winding and FB (pin 1), the auxiliary voltage is sampled at the middle of the de-magnetization and it is hold until the next sampling. The sampled voltage is compared with reference voltage Vref (typical 2.5V) and the difference is amplified. The error amplifier output reflects the load condition and controls the switching off time to regulate the output voltage, thus constant output voltage can be achieved. When the sampled voltage is below Vref and the error amplifier output reaches its minimum, the switching frequency is controlled by the sampled voltage to regulate the output current, thus the constant output current can be achieved. br ig  Operating Current The Operating current of OB2305 is as low as 650uA (typical). Good efficiency and les than 30mW standby power is achieved with the low operating current. O n-  CC/CV Operation OB2305 is designed to produce good CC/CV control characteristic as shown in the Figure. 1. In charger applications, a discharged battery charging starts in the CC portion of the curve until it is nearly full charged and smoothly switches to operate in CV portion of the curve. The CC portion provides output current limiting. In CV operation, the output voltage is regulated through the primary side control. In CC operation mode, OB2305 will regulate the output current constant regardless of the output voltage drop.  Adjustable CC point and Output Power In OB2305, the CC point and maximum output power can be externally adjusted by external current sense resistor Rs at CS pin as illustrated in the typical application diagram. The larger Rs, the smaller CC point is, and the smaller output power  Principle of Operation To support OB2305 proprietary CC/CV control, system needs to be designed in DCM mode for ©On-Bright Electronics Confidential -7- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller becomes, and vice versa as shown in Figure.3. winding inductance results in the change of the maximum output power and the constant output current in CC mode. To compensate the change from variations of primary winding inductance, the switching frequency is locked by an internal loop and the switching frequency is FSW  1 (4) 2TDemag 佳 Since TDemag is inversely proportional to the inductance, as a result, the product Lp and fsw is constant, thus the maximum output power and constant current in CC mode will not change as primary winding inductance changes. Up to ±7% variation of the primary winding inductance can be compensated. 福 Figure.3. Adjustable output power by changing Rs o  On time OCP compensation The variation of max output current in CC mode can be rather large if no compensation is provided. The OCP threshold value is self adjusted higher at higher AC voltage. This OCP threshold slope adjustment helps to compensate the increased output current limit at higher AC voltage. In OB2305, a proprietary OCP compensation block is integrated and no external components are needed. The OCP threshold in OB2305 is a function of the switching ON time. For the ON time between 2.0us to 4.0us (typical), the OCP threshold changes linearly from 500mV to 550mV. For the ON time larger than 4.0us, the OCP threshold is clamped to 550mV, as shown in Figure 4. ht c on fid en tia lt  Programmable Cable Drop Compensation In OB2305, cable drop compensation is implemented to achieve good load regulation. An offset voltage is generated at FB pin by an internal current flowing into the resister divider. The current is proportional to the switching off time, as a result, it is inversely proportional to the output load current, and the drop due to the cable loss can be compensated. As the load current decreases from full-load to no-load, the offset voltage at FB will increase. It can also be programmed by adjusting the resistance of the divider to compensate the drop for various cable lines used. The percentage of maximum compensation is Icomp _ cable  R1//R2 10 6 V  100% 2.5 Vout V is load compensation voltage and Vout is output voltage; For example: R1//R2=6.2Kohm, the percentage of maximum compensation is n- br ig V 47  6200  10 6   100%  11.6% Vout 2.5 Figure.4. On time OCP compensation O  Operation Switching Frequency The switching frequency of OB2305 is adaptively controlled according to the load conditions and the operation modes. For flyback operating in DCM, the maximum output power is given by Po MAX  1 LP FSW I p2 2 Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in OB2305. The switch current is detected by a sense resistor into the CS pin. An internal leading edge blanking circuit chops off the sensed voltage  (3) Where Lp indicate the inductance of primary winding and Ip is the peak current of primary winding. Refer to the equation 3, the change of the primary ©On-Bright Electronics Confidential -8- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller spike at initial power MOSFET on state so that the external RC filtering on sense input is no longer needed.  Protection Control Good power supply system reliability is achieved with its rich protection features including Cycle-by-Cycle current limiting (OCP), Output over voltage protection, VDD over voltage protection, short circuit protection, Under Voltage Lockout on VDD (UVLO) and over temperature protection (OTP). VDD is supplied by transformer auxiliary winding output. The output of OB2305 is shut down when VDD drops below UVLO (ON) and the power converter enters power on start-up sequence thereafter. To prevent the circuit being damaged under abnormal conditions, OB2305 provides over thermal protection function. When the die temperature rises above over temperature threshold T_otp, the OB2305 will shut down the gate output and then latch the power supply off. The controller will remains latched until the die temperature drops below the recovery threshold T_otp_rec and the OB2305 will reset at the same time. 佳  Gate Driver The GATE pin is connected to the gate of an external power switch. An internal 13.5V (typical) clamp is added for MOSFET gate protection at high VCC voltage. When VCC voltage drops below UVLO(ON), the GATE pin is internally pull low to maintain the off state. O n- br ig ht c on fid en tia lt o 福  CC mode shutdown function In OB2305, to prevent the controller operating under abnormal conditions, the minimum output voltage of CC mode is limited to predetermined voltage. The CC output voltage is sampled through FB pin from auxiliary winding at the middle of the de-magnetization. When the FB sampled voltage is below 1.55V and last 1024-2048 cycle, the controller will shut down. ©On-Bright Electronics Confidential -9- Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller Dimensions In Millimeters Dimensions In Inches Min Max Min Max br ig Symbol ht c on fid en tia lt o 福 佳 PACKAGE MECHANICAL DATA 1.000 1.450 0.039 0.057 A1 0.000 0.150 0.000 0.006 A2 0.900 1.300 0.035 0.051 b 0.300 0.500 0.012 0.020 c 0.080 0.220 0.003 0.009 D 2.800 3.020 0.110 0.119 E 1.500 1.726 0.059 0.068 E1 2.600 3.000 0.102 0.118 O n- A e 0.950 (BSC) 0.037 (BSC) e1 1.800 2.000 0.071 0.079 L 0.300 0.600 0.012 0.024 θ 0º 8º 0º 8º ©On-Bright Electronics Confidential - 10 - Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller Dimensions In Millimeters br ig Symbol ht c on fid en tia lt o 福 佳 PACKAGE MECHANICAL DATA Max Min Max 1.350 1.750 0.053 0.069 0.050 0.250 0.002 0.010 A2 1.250 1.650 0.049 0.065 b 0.310 0.510 0.012 0.020 c 0.100 0.250 0.004 0.010 D 4.700 5.150 0.185 0.203 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 A1 O n- A Min Dimensions In Inches e 1.270 (BSC) 0.050 (BSC) L 0.400 1.270 0.016 0.050 θ 0º 8º 0º 8º ©On-Bright Electronics Confidential - 11 - Preliminary datasheet OB_DOC_DS_230500 OB2305 High Precision CC/CV Primary-Side Controller IMPORTANT NOTICE RIGHT TO MAKE CHANGES On-Bright Electronics Corp. reserves the right to make corrections, modifications, enhancements, improvements and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. o 福 佳 WARRANTY INFORMATION On-Bright Electronics Corp. warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with its standard warranty. Testing and other quality control techniques are used to the extent it deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. On-Bright Electronics Corp. assumes no liability for application assistance or customer product design. Customers are responsible for their products and applications using On-Bright’s components, data sheet and application notes. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. on fid en tia lt LIFE SUPPORT On-Bright Electronics Corp.’s products are not designed to be used as components in devices intended to support or sustain human life. On-bright Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in medical applications. O n- br ig ht c MILITARY On-Bright Electronics Corp.’s products are not designed for use in military applications. On-Bright Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in military applications. ©On-Bright Electronics Confidential - 12 - Preliminary datasheet OB_DOC_DS_230500