Fremont Micro Devices FT831D Primary-Side-Control CC/CV Controller DESCRIPTION FEATURES Constant-Current (CC) and Constant-Voltage The FT831D controller device is optimized for (CV) Control with Primary Side Control high-performance, low power switching mode power ±5% Constant Voltage Regulation supply applications That needed adjustable cable ±10% Constant Current Regulation compensation. The FT831D facilitates CC/CV Eliminates Opto-Coupler and TL431 charger design by eliminating an opto-coupler and External Power NPN Transistor for Low Cost TL431. Its highly integrated functions such as Under Operation Frequency Modulation Improve Voltage Lockout (UVLO), Leading Edge Blanking System EMI (LEB), external adjustable base driver and cable Adjustable 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em Cable compensation for all Loading compensation offer the users a high efficiency and low cost solution for AC/DC power applications. Built-in Line Compensation Cycle-by-Cycle Current Limiting Furthermore, FT831D features fruitful protections Over Voltage Protection (OVP) like OTP (Over Temperature Protection), OVP (Over Over Temperature Protection (OTP) Voltage Protection), and Open Circuit Protection, Open Circuit Protection Short Circuit Protection to eliminate the external Short Circuit Protection protection circuits and provide reliable operation. Pb-Free Device FT831D is available in SOT23-6 packages. TYPICAL APPLICATION Adapter/Charger for Cell/Cordless Phones, PDAs, MP3 and Other Portable Apparatus Standby and Auxiliary Power Supplies Set Top Boxes (STB) © 2012 Fremont Micro Devices Inc. DS831D-A0-page1 Fremont Micro Devices FT831D TYPICAL APPLICATION CIRCUIT 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em Figure 1: Typical Application Circuit ABSOLUTE MAXIMUM RATINGS FB to GND………………………………...…………………………………….…….……….….............. -0.3V to +9V CS to GND…………………………………………...……………………………………….………….....-0.3V to +9V VCC to GND…………………………………..………….…………………………………………..……-0.3V to +18V OUT to GND…………………………………...…………………………….……….……………...…......-0.3V to +9V CABLE to GND……………………………………………………………….………….……………........-0.3V to +9V Operating Temperature Range……………………...……………………………………………...-40℃ to +125℃ Junction Temperature………………………………..…………………………………………..........-40℃ to +150℃ Storage Temperature Range ……………………………..…………………………………….…….-60℃ to +150℃ ESD Protection HBM……………….....…………………………………………………………………….….2000V MM…………………..……………………………………………………………………….500V Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. © 2012 Fremont Micro Devices Inc. DS831D-A0-page2 Fremont Micro Devices FT831D PIN CONFIGURATION Figure 2: Pin Assignments Pin Definition 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em Pat No. Package FT831D SOT23-6 1 2 CS FB 3 4 5 GND OUT VCC 6 CABLE Table 2: Pin Definition TERMINAL DEFINITION Pin Description GND Ground. FB Output voltage feedback pin CS Primary current sense VCC Supply voltage OUT NPN switch base driver CABLE Adjust cable compensation by an external resistor and capacitor to GND Table 3 ORDERING INFORMATION FT831D X –XX Circuit Type HSF and Packaging Blank: RoHS and T&R Package -GT: Green and T&R Blank: SOT23-6 Package SOT23-6 Temperature Range -40℃-125℃ HSF Packaging Ordering Code RoHS Tape and Reel FT831D Green Tape and Reel FT831D-GT Table4 © 2012 Fremont Micro Devices Inc. DS831D-A0-page3 Fremont Micro Devices FT831D MARKING RULE Figure 3: Marking Rule SOT23-6: 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em ①: Represents Version (D) ②: Represents package (a: SOT23-5; b: SOT23-6) ③④: for internal reference BLOCK DIAGRAM VCC VDD Band Gap LDO Ref POR 12.1/5.1V Vcc_on/Vcc_off Ibias 150uA Ifb_open Internal reference &bias UVLO OTP OTP FB_open 4.65V Vovp Delay 3uS Ovp COMP POR CCM Protection S R SET CLR Q Q CC Controller COMP 0.1V Vcp Ifb FB CV Controller EA S R 3 x (1+Kcab)V SET CLR Driver Q Q OUT VDD Loading detect 3V Vfb CS FT831D LEB 400ns COMP Vline 0.5V Vcs CABLE GND Figure 4: FT831D Block Diagram © 2012 Fremont Micro Devices Inc. DS831D-A0-page4 Fremont Micro Devices FT831D ELECTRICAL CHARACTERISTICS (For typical values Tj=25℃, Vcc=10V, unless otherwise noted) Characteristic Symbol Min Typ Max Unit Maximum Current Threshold Vcs_max 0.49 0.5 0.51 V Pre-drive Current Threshold Vcs_pre 0.44 0.45 0.46 V Current Sense Vcs_limit Temperature Stability (-40℃~125℃) Leading Edge Blanking Duration Tleb Propagation Delay (OUT=1.0nF to GND) Tpd 1 % 400 ns 200 ns Feedback Section 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em Feedback Voltage Threshold Vfb FB Pin minimum current Ifb_open OVP Protection Threshold Level Vovp CCM protection Threshold Level Vcp 3.17 3.2 3.23 50 4.55 4.65 V μA 4.75 0.1 V V Supply Section Start Up Threshold Voltage Vcc_on 13.5 15 17.2 V Under Voltage Lockout Voltage Vcc_off 4.8 5.4 6 V VCC Start Up Current Istart_up Operating Current 6 uA Iop 1.1 mA Feedback Loop Open Protection Ifb_open 150 uA Over Temperature Protection Tsd 140 ℃ Protection Section Base Driver Output Maximum Sink current Isink 50 mA Output Maximum Source current Isource 30 mA Vline 45 mV Compesation Line Compensation (Ifb=1mA) Percentage of Output Cable Resistance Kcab*2 Compensation Kcab % *1 (Kcab=6.5/560×R7 ×10e-3) Table 5 *1 *2 (R7): Resistor connected between Pin CABLE and GND (Kcab): Cable compensation percentage in output voltage © 2012 Fremont Micro Devices Inc. DS831D-A0-page5 Fremont Micro Devices FT831D FUNCTIONAL DESCRIPTION Operating Description FT831D are cost effective and high-performance AC-DC power supply controller for off-line low power AC-DC applications including battery chargers and adaptors. Without secondary feedback circuit, the constant voltage (CV) and constant current (CC) control can be achieved accurately. Start up Control Start-up current of FT831D is very low so that a start-up resistor with high resistance and low-wattage is allowed to supply the start-up power for the controller. The large value startup resistor can minimize the power loss in application and starts up quickly. A 1.5Mo, 0.25W start-up resistor and a 10uF/25V Vdd hold-up capacitor are sufficient for an AC-to DC power adapter. 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em Operating current The operating current of FT831D series is as low as 1mA. Good efficiency is achieved with the low operating current together with valley turn on of the external power NPN transistor. Low operating current also reduces the Vcc hold-up capacitance requirement. Constant voltage (CV) and constant current (CC) Operation The FT831D can accurately achieve CV/CC characteristic output without secondary side voltage and current-feedback circuits. It operates in CV mode to regulate the output voltage by capturing the auxiliary winding feedback voltage at FB pin. The auxiliary winding feedback voltage is proportional to secondary winding, so it provides controller the feedback signal from secondary side and achieves constant-voltage output. In CC mode, the controller detects the secondary discharger peak current and the discharger time, which determines the off-time of the base driver to make the output average current constant. In the CV or CC mode, the primary side peak current is constant if the Rcs is settled. Leading edge blanking Each time the power NPN transistor is switched on, a turn-on spike occurs at the sense resistor. To avoid premature termination of the switching pulse, a 400ns leading edge blanking time is built in. Conventional RC filtering can therefore be omitted. During this blanking period, the current limit comparator is disabling and cannot switch off the base driver. Under voltage lockout (UVLO) FT831D turn-on [Vcc(on)] and turn-off [Vcc(off)] are 15V and 5.4V. During start-up, the hold-up capacitor must to be charged to 15V through the start-up resistor. The hold-up capacitor continues to supply Vcc until power can be delivered from the auxiliary winding of the transformer. Vcc must not drop below 5.4V during this start-up process. This UVLO hysteresis window ensures that hold-up capacitor is sufficient to supply Vcc during start-up. Protection control With rich protection features of FT831D, a good power supply system reliability is achieved. The protection features including cycle by cycle current limiting, Vcc over voltage protection and clamp, © 2012 Fremont Micro Devices Inc. DS831D-A0-page6 Fremont Micro Devices FT831D short circuit protection, feedback loop open protection, over temperature protection and under voltage lockout on Vcc. Base driver To minimize loss in the primary power NPN and prevent from second breakdown, the driving current is carefully controlled. The driving current have a default driving current 30mA. Output cable compensation The output cable compensation provides a constant output voltage at the end of the cable over the entire load rang in constant voltage mode. As the converter load increase from no-load to the peak power point, the voltage drop introduced across the output cable in compensated by increasing the feedback pin reference voltage. The correct degree of compensation can be adjustable externally in 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em product FT831D . With this feature, user can conveniently determine the correct degree of compensation base on the cable selected. © 2012 Fremont Micro Devices Inc. DS831D-A0-page7 Fremont Micro Devices FT831D SOT23-6 PACKAGE OUTLINE DIMENSIONS 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 1.050 1.250 0.041 0.049 A1 0.000 0.100 0.000 0.004 A2 1.050 1.150 0.041 0.045 b 0.300 0.500 0.012 0.020 c 0.100 0.200 0.004 0.008 D 2.820 3.020 0.111 0.119 E 1.500 1.700 0.059 0.067 E1 2.650 2.950 0.104 0.116 e 0.950 (BSC) 0.037（BSC） e1 1.800 2.000 0.079 L 0.300 0.600 0.024 θ 0° 8° © 2012 Fremont Micro Devices Inc. 0° 8° DS831D-A0-page8 Fremont Micro Devices FT831D 司 4 公 88 限 71 有 207 m 技 83 o c 科 1 . 8 锦 7 5 1 鹏 1 市 颖 030 2512 圳 3 pj 0 0 g@ 深 7 6 何 ： ron Q Q ail:p Em * Information furnished is believed to be accurate and reliable. However, Fremont Micro Devices, Incorporated (BVI) assumes no responsibility for the consequences of use of such information or for any infringement of patents of other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Fremont Micro Devices, Incorporated (BVI). Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. Fremont Micro Devices, Incorporated (BVI) products are not authorized for use as critical components in life support devices or systems without express written approval of Fremont Micro Devices, Incorporated (BVI). The FMD logo is a registered trademark of Fremont Micro Devices, Incorporated (BVI). All other names are the property of their respective owners. © 2012 Fremont Micro Devices Inc. DS831D-A0-page9