BD8624EFV-E2

TECHNICAL NOTE System Power Supply for TV Series Built-in 1ch FET Synchronous Rectification Type DC/DC converters BD8628EFV, BD8624EFV ●Description BD8628EFV / BD8624EFV have realized the high performance and reliability required as a power supply for thin-screen TV. With built-in FET 1ch current mode control, the DC/DC Converter series has the advantage of high-speed load response and wide phase margin. 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) 1ch synchronous rectification step-down system DC/DC converter 2) Soft start, soft off function 3) Built-in low voltage / overvoltage protection function 4) Built-in overcurrent protection function 5) Frequency setting by external resistance is available. (RT terminal) 6) Protection time setting by external resistance is available. (RSET terminal) 7) Built-in RT / RSET terminal open/short protection function 8) Protection control with built-in sequencer 9) Built-in adjustment function time of off latch 10) Built-in error state detection signal output function 11) Built-in tracking function 12) Corresponded to protecting bus 13) Load current Maximum 3A 14) HTSSOP－B24 Package Aug. 2008 ● Electric characteristic (Ta=25℃, VCC=6.5V, GND=0V,CTL=6.5V unless otherwise specified.) Parameter Circuit current 1 Circuit current 2 < Error amplifier part > Standard voltage （VREF） Terminal FB Input bias current Terminal FC Clamping voltage H Terminal FC Clamping voltage L Terminal FC Sink current Terminal FC Source current Open loop gain Symbol IQ1 IQ2 VREF IFBB VFCH VFCL Terminal SS Protection circuit start voltage Terminal SS Protection circuit start voltage Maximum hysteresis error specification value TYP MAX 0 10 3.4 - UNIT Condition μA mA CTL=0V CTL=VCC Terminal FB and FC terminal short 0.792 -1 1.8 0.5 - 0.8 0 100 0.808 1 0.2 -70 - V μA V V mA μA dB FOSC 400 500 600 kHz ISS VSSTH VSSCLM VSSSTB RSS VSSPON -3 0.98 2.2 0.1 49 1.0 -2.5 1.08 2.4 0.15 70 1.1 -2 1.18 91 1.2 μA V V V kΩ V VSS Voltage (L→H) CTL=0V VSS Voltage (L→H) VSSPON_HYS 10 100 200 mV VSS Voltage VLVP VOVP 0.51 0.86 0.56 0.96 0.61 1.06 V V VFB Voltage VFB Voltage Ilmt VCC-0.9 VCC-0.7 VCC-0.5 V VSW Voltage RONU RONL - 110 110 - mΩ mΩ VBOOT－VSW =5V VVREG5=5V VOL_PDET VIH_CTL VIL_CTL II_CTL 2.0 - 60 0.4 VCC 0.5 90 V V V μA IOL=100uA CTL terminal CTL terminal CTL terminal, CTL=VCC IFCSINK IFCSOURCE AVERR Oscillation frequency Charging current Terminal SS Threshold voltage Terminal SS Clamping voltage Terminal SS Standby voltage Terminal SS Discharge resistance MIN - VFB=0.9V VFB=0.7V VFB=0.9V VFB=0.9V, VFC=0.4V VFB=0.7V, VFC=1.6V When terminal RT 27kΩ is connected VSS=1.0V VSS Voltage < Low voltage, over voltage detection part＞ Terminal FB Low voltage detection voltage Terminal FB Overvoltage detection voltage < Over current detection part＞ Output current limitation threshold Upper side MOS ON resistance Lower side MOS ON resistance VIHCTL ON control VIHCTL >VLVP+VLVP_HYS OFF 1.1V(typ) >VIHCTL