BD8622EFV-E2

System Power Supply for TV Series Built-in 1ch FET Light Load Type DC / DC converters BD8622EFV No.09034EAT04 ●Description BD8622EFV has realized the high performance and reliability required as a power supply for thin-screen TV. Due to the high-speed load response, it is most suitable for TV-purpose processors with increasingly high performance, and due to the wide phase margin it leaves a good margin for board pattern & constant setting and so facilitates its application design. As a high-reliability design, it has various built-in protection circuits (overcurrent protection, output voltage abnormal protection, thermal protection, and off-latch function at the time of abnormality etc.), therefore as an advantage it does not easily damage in every possible abnormal condition such as all-pin short circuit test etc. and hence most suitable for thin-screen TV which requires the high reliability. ●Features 1)High efficiency in all load area 2)3.0A output current 3)PWM mode/PFM mode switch(automatic operation) 4)Low current mode/Rorripplmord switch with terminal MODE 5)Low RDS(ON) internal switches:75mΩ(typ.) 6)±1% reference voltage accuracy 7)Programmable frequency : 250kHz-1MHz (Can the adjustment by an external synchronization and the terminal RT resistance.) 8)Terminal RT OPEN/SHORT detecting function 9)Over current protection function 10) Output over voltage/low voltage protection function (over : FB > VREF +60mV , low : FB < VREF -60mV) 11) Timer off latch function in abnormal circumstances 12) Thermal shutdown function 13) Under voltage protection 14) Soft start/start delay circuit 15) Soft start time out function 16) Protecting BUS function with terminal PDET 17) HTSSOP-B20 package www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 1/15 2009.05 - Rev.A BD8622EFV ●Electrical characteristics (Unless otherwise noted Ta=25℃, VIN=3.3V, GND=0V) Technical Note Specification value UNIT Condition MIN TYP MAX VIN supply current (operating) IQ_active 210 350 μA VFB = 0.83V, VFC = 1V VIN supply current (standby) IQ_stby 0 1 μA VEN = 0V Reference voltage (VREF) VREF 0.792 0.8 0.808 V Output rise detection voltage VOVP 30 60 90 mV Monitoring FB terminal Output decrease detection voltage VLVP -90 -60 -30 mV Monitoring FB terminal Terminal PDET output current IPDET 0.4 mA VPDET< 0.3V Oscillation frequency fOSC 500 550 600 kHz RRT= 220kΩ Pch FET ON resistance RPFET 75 110 mΩ ISW = 1A UVLO voltage VUVLO 2.35 2.50 2.65 V SW leak current ILSW 0 1 μA VEN= 0V, VIN = 5.5V EN terminal H threshold voltage VENH 1.1 V EN terminal L threshold voltage VENL 0.4 V FC sink current IFCSI 10 20 μA FC source current IFCSO -20 -10 μA SS/DELAY terminal source current ISSSO 2 4 6 μA Terminal PDET pull-up resistor RPDET 100 170 250 kΩ VFB :FB terminal voltage, VEN :EN terminal voltage, VFC :FC terminal voltage, VPDET: PDET terminal voltage Current capability should not exceed Pd. Parameter Symbol www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 2/15 2009.05 - Rev.A BD8622EFV ●Block diagram Technical Note SGND RT OSC 1 FB 2 PDET 0.8V 20 FC 19 SS/DELAY Err AMP 3 NC Detect Abnormal Voltage and Start error Shut Down PWM/PFM CONTROL 18 MODE 17 en enable 4 SW EN 16 NC 15 SVIN 5 SW 6 SW SVIN 14 VIN 13 VIN 12 VIN 11 7 SW Predrive 8 NC 9 PGND 10 VIN Fig1 Block diagram ●Pin Description No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Symbol Description SGND Signal GND terminal Feed back terminal FB PDET NC SW SW SW SW NC PGND VIN VIN VIN VIN NC EN MODE Abnormal state notification and external IC abnormality detection terminal Explanation Small signal system GND Output voltage detection Protecting BUS communication terminal Switching output terminal Power GND terminal GND for power MOSFET Power supply input terminal Power supply input. The decoupling is done to PGND Enable input MODE selection terminal 18 SS/DELAY Soft start adjustment capacity connection terminal Error amplifier output Error amplifier phase compensation point 19 FC Frequency adjustment resistance connection terminal The switching frequency is set by the connected resistance 20 RT ON/OFF control for device operation The operation mode is switched according to the input voltage at a light load. The soft start time is adjusted with the connected capacitor www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 3/15 2009.05 - Rev.A BD8622EFV ●Pin equivalence circuit diagram No. 1 Symbol SGND Explanation GND (connected 0V) Technical Note Terminal equivalent circuit diagram 2 FB Output voltage detection terminal 3 PDET Protecting BUS I/O terminal 5,6,7,8 SW Output terminal 10 PGND Power GND (Same voltage as SGND) 11,12,13 PVIN Power supply input terminal 14 SVIN Power supply input terminal www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 4/15 2009.05 - Rev.A BD8622EFV No. Symbol Explanation Technical Note Terminal equivalent circuit diagram 16 EN Enable terminal 17 MODE Operation mode switch terminal at light load www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 5/15 2009.05 - Rev.A BD8622EFV No. Symbol Explanation Technical Note Terminal equivalent circuit diagram 18 SS /DELAY Soft start time adjustment terminal 19 FC Error amplifier compensation terminal 20 RT Oscillator frequency adjustment terminal www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 6/15 2009.05 - Rev.A BD8622EFV Technical Note ●Operation description Enable control The device can be controlled ON/OFF by EN terminal (16 pin) voltage. An internal circuit starts when VEN reaches 1.1V. When standing up of VIN is too steep (1msec or less), a defective start might be caused according to the state of Pascon between GND substrate pattern and power supply-when the terminal EN is short-circuited to the terminal VIN and it is used. VEN EN terminal VENH VENL 0 VSSCLM SS terminal VSSTH VSS 0 VO Output setting voltage 0 tSS Fig.2 ON/OFF transition wave form in EN controlling www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 7/15 2009.05 - Rev.A BD8622EFV Technical Note Soft start time set function As for BD8622EFV, output can do soft start without overshoot by charging soft start capacity (CSS) connected between SS and SGND terminal. Also, soft start time (tss) can be set by setting soft start capacity (CSS) arbitrarily. OSC oscillation frequency setting function The output oscillation frequency can be set by connecting resistance between terminal RT (20 pins) and SGND (range = 250kHz - 1MHz) The relation between RT terminal resistance and the oscillation frequency follows Fig.4. 1000 Frequency [kHz] 10 10 100 1000 10000 Frequency [kHz] RT terminal resistance [kΩ] Fig.4 RT resistance-oscillation frequency www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 8/15 2009.05 - Rev.A BD8622EFV Technical Note Light load mode operation ・Low current mode When the terminal MODE (17 pins) is made "H", low current mode operation becomes effective. The characteristic of the efficiency valuing is obtained in low current mode operation at a light load. [20mV/DIV] VOUT SW [2V/DIV] IL [200mA/DIV] Fig.5 Low current mode operation ・Low ripple mode When the terminal MODE is made "L", the Low ripple mode operation becomes effective. It becomes operation of valuing a low ripple in the Low ripple mode operation at a light load. VOUT [20mV/DIV] SW [2V/DIV] IL [200mA/DIV] Fig.6 Low ripplemord operation 100 90 80 70 Low current mode Efficiency [%] 60 50 40 30 20 10 0 1 10 100 Low ripple mord VIN=3.3V VO=1.8V Io=0～100mA SW_f=550KHz(R11=220KΩ) Negative overcurrent [mA] Fig7 Light load mode efficiency comparison www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 9/15 2009.05 - Rev.A BD8622EFV ● Protection function Technical Note Protection circuit is effective for destruction prevention due to accident so that avoid using under continuous protection operation. Low voltage protection function (LVP) The voltage of the terminal FB (2 pins) is compared with internal reference voltage VREF. If FB terminal voltage falls below VLVP(= VREF -60mV) and the state continues for 500us, output changes to low voltage and the state is fixed. In that case , PDET (3pin) output changes to L. Table 1 output low voltage protection function EN terminal >VENH 1.4V(typ) VOVP Effective VENH 1.4V(typ)